SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES • NUMBER 2

Field and Laboratory Investigations

of Meteorites from Victoria Land

and the Thiel Mountains Region, Antarctica,

1982-1983 and 1983-1984

Ursula B. Marvin

and Glenn J. MacPherson

EDITORS

SMITHSONIAN INSTITUTION PRESS

Washington, D.C.

1989

MAR 0 a 1989
ABSTRAC T

Marvin, Ursula B., and Glenn J. MacPherson, editors. Field and Laboratory Investigations

of Meteorites from Victoria Land and the Thiel Mountains Region, Antarctica, 1982-1983 and

1983-1984. Smithsonian Contributions to the Earth Sciences, number 28, 146 pages,

frontispiece, 86 figures, 14 tables, 1989.—This monograph describes the meteorite collecting

activities of the United States Antarctic Search for Meteorites (ANSMET) expeditions of the

1982-1983 and 1983-1984 field seasons. Descriptions and classifications are given of most

specimens collected during the 1982-1983 season and some of those collected in the 1983-1984

season. Articles are included reviewing topics such as Antarctic achondrites, carbonaceous

chondrites, meteorite weathering under polar conditions, trace element contents of Antarctic

meteorites in comparison with those found elsewhere, and the meteorite pairing problem. One

chapter describes the crystalline fabric of the ice surrounding a meteorite discovered emerging

at the surface. The Appendix lists all ANSMET specimens classified as of June 1984, in

numerical order for each locality and by meteorite class. The Appendix also includes a tentative

list of paired specimens.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is

recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Aerial

view of Ulawun Volcano, New Britain.

Library of Congress Cataloging in Publication Data

Field and laboratory investigations of meteorites from Victoria Land and the Thiel Mountains Region, Antarctica,

1982-1983 and 1983-1984.

(Smithsonian contributions to the earth sciences ; no. 28)

"This monograph describes the meteorite collecting activities of the United States Antarctic Search for Meteorites

(ANSMET) expeditions of the 1982-1983 and 1983-1984 field seasons"—P.

Bibliography: p.

1. Meteorites—Antarctic regions—Victoria Land. 2. Meteorites—Antarctic regions—Thiel Mountains Region. I. Marvin, Ursula B. II. MacPherson, Glenn J. III. Series.

QE1.S227 no. 28 550s 88-600361

[QB755.5.A6] [523.5'1]
Contents

Page

1. EDITOR'S INTRODUCTION, by Ursula B. Marvin and Glenn J. MacPherson .. . 1

2. THE 1982-1983 ANTARCTIC SEARCH FOR METEORITES (ANSMET) FIELD

PROGRAM, by William A. Cassidy 5

3. THE EXPEDITION TO THE THIEL MOUNTAINS AND PECORA ESCARPMENT,

1982-1983, by John W. Schutt 9

4. EXTENSION OF THE ALLAN HILLS TRIANGULATION NETWORK SYSTEM,

by John O. Annexstad and Kristine M. Annexstad 17

5. THE FIELD SEASON IN VICTORIA LAND, 1983-1984, by Robert F. Fudali and

John W. Schutt 23

6. DESCRIPTIONS OF STONY METEORITES, by Brian Mason, Glenn J. MacPherson,

Roberta Score, Carol Schwarz, and Jeremy S. Delaney 29

7. DESCRIPTIONS OF SOME ANTARCTIC IRON METEORITES, by Roy S. Clarke, Jr.. 61

8. OVERVIEW OF SOME ACHONDRTTE GROUPS, by Jeremy S. Delaney and

Martin Prinz 65

9. ANTARCTIC CARBONACEOUS CHONDRITES: NEW OPPORTUNITIES FOR

RESEARCH, by Harry Y. McSween, Jr 81

10. THE EMERGING METEORITE: CRYSTALLINE STRUCTURE OF THE ENCLOSING

ICE, by Anthony J. Gow and William A. Cassidy 87

11. SIGNIFICANCE OF TERRESTRIAL WEATHERING EFFECTS IN ANTARCTIC

METEORITES, by James L. Gooding 93

12. TRACE ELEMENT VARIATIONS BETWEEN ANTARCTIC (VICTORIA LAND) AND

NON-ANTARCTIC METEORITES, by Michael E. Lipschutz 99

13. PAIRING OF METEORITES FROM VICTORIA LAND AND THE THIEL MOUNTAINS,

ANTARCTICA, by Edward R.D. Scott 103

14. METEORITE DISTRIBUTIONS AT THE ALLAN HILLS MAIN ICEFIELD AND THE

PAIRING PROBLEM, by Ursula B. Marvin 113

APPENDIX: Tables of ANSMET Meteorites 121

HI
2 cm

FRONTISPIECE.—The emerging meteorite, ALH82102. Left: The meteorite sitting in its enclosing ice after the

block had been sawn in half. Right: A thin section of the enclosing ice shown in cross-polarized light. Flattened,

horizontal ice crystals curve upwards toward the mold of the meteorite at top left of the photo. (Both photographs

are at the same scale.)
Field and Laboratory Investigations

of Meteorites from Victoria Land

and the Thiel Mountains Region, Antarctica,

1982-1983 and 1983-1984

1. Editors' Introduction

Ursula B. Marvin and Glenn J. MacPherson

This is the fourth publication in the Smithsonian Contributions to the Earth Sciences series to present the results of

the yearly United States Antarctic Search for Meteorites

(ANSMET) expeditions to Antarctica. This issue describes the

1982-1983 and 1983-1984 field seasons in Victoria Land (at

about 76°77/S, 159°E) and in the Thiel Mountains region,

which lies nearer the South Pole at about 85°86'S, 90°W

(Figure 1-1). It includes chapters describing and classifying the

meteorites collected in these two seasons, and giving overviews

of topics such as the range and character of Antarctic

achondrites and carbonaceous chondrites, studies of meteorite

weathering under polar conditions, and discussions of the

difficult problem of pairing—identifying which specimens are

fragments from the same meteorite fall. The first meteorite

caught in the act of emerging at the surface of the ice is

described, as is the crystalline fabric of the ice surrounding it.

Appendix Table A lists all meteorites classified through June

1984 in numerical order for each locality; Appendix Table B

lists specimens in consecutive order by meteorite class; and

Appendix Table C lists those groups of paired specimens that

are generally agreed upon at the present time. Paired groups

should always be regarded as tentative because new analyses

may identify specimens that do not belong to a group or

additional specimens that do.

The numbers and main categories of meteorite specimens

collected in the 1982-1983 and 1983-1984 seasons are listed

Ursula B. Marvin, Smithsonian Astrophysical Observatory, Mail Stop

52, 60 Garden Street, Cambridge, Massachusetts 02138. Glenn J.

MacPherson, Department of Mineral Sciences, National Museum of

Natural History, Smithsonian Institution, Washington, D.C. 20560.

in Table 1-1. Total numbers and aggregate weights of

specimens of each meteorite class are given in Appendix Table

B. The aggregate weights are of interest because of the inherent

intractability of the pairing problem. We are unlikely ever to

obtain secure counts of the number of falls of each meteorite

class represented on the Antarctic stranding surfaces, and so

we cannot compare numbers of Antarctic falls with those in

the rest of the world. We can, however, obtain aggregate

weights and, allowing for the vagaries of discovery, gain a

general idea of how relative proportions of meteorite classes

in the Antarctic collections compare with those found

elsewhere.

The system for naming Antarctic meteorites was changed

in 1982 by the dropping of a letter (A, for example) to designate

the collecting expedition. When the system was originally

adopted, some members of the Nomenclature Committee

looked forward optimistically to a time when two or more

expeditions, from different countries or organizations, might

visit an area such as the Allan Hills during the same season.

They foresaw the need for a letter (A, B, C) to identify each

one. Hence, letters and numbers in a name such as ALHA76001

were chosen to indicate place, expedition, year, and specimen

number: ALH (Allan Hills), A (Expedition A), 76 (1976), 001

(Specimen 1). In practice, however, meteoriticists viewed the

expedition letter as incomprehensible and unnecessary. It has

been dropped for all meteorites collected after the 1981 season;

thus, the first Allan Hills specimen of 1982 was ALH82001.

The ANSMET program is governed by an interagency

agreement between the National Science Foundation, the

Smithsonian Institution, and the National Aeronautics and

1
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 1-1.—Numbers of classified meteorite specimens collected in the

1982-1983 and 1983-1984 (in parentheses) seasons.

Locality

Ordinary Carbonaceous

chondrites chondrites Achondrites Irons

Allan Hills

Elephant Moraine

Pecora Escarpment

Thiel Mountains*

Taylor Glacier

Inland Forts

39 (77)

16(183)

25

14

1

4(3)

(3)

1

2(3)

1(15)

3

2

(3)

*Thiel Mountains includes specimens collected at the Davies and Moulton

Escarpments.

Space Administration. At the request of the scientific

community, procedures (based on those used for lunar samples)

were adopted for collecting specimens by sterile techniques

and keeping them frozen until they are processed in

nitrogen-filled cabinets at the Johnson Space Center at

Houston. Details of the field and laboratory procedures are

outlined in the first publication in this series (Marvin and

Mason, 1980). In order to distribute research samples quickly

and widely, all newly classified specimens are described in the

Antarctic Meteorite Newsletters; these are mailed, on request,

to investigators throughout the world. Any scientist wishing

to obtain samples may submit a request, describing the

proposed research and the numbers, weights, and types of

samples required, to the Meteorite Working Group, a

committee with a rotating membership responsible for

monitoring the program and allocating samples. Requests for

the Antarctic Meteorite Newsletter or for research materials

should be addressed to the Secretary, Meteorite Working

Group, Lunar and Planetary Institute, 3303 NASA Road 1,

Houston, Texas 77058.

The Antarctic Meteorite Working Group meets twice each

year, usually in April and September. Each issue of the

newsletter publishes dates of meetings and deadlines for

requests. Sample requests are welcome from all qualified

scientists and are considered on the basis of their merit

regardless of whether a scientist is funded for meteorite

research. The allocation of Antarctic meteorite samples does

not in any way commit a funding agency to support the

proposed research.

For references on Antarctic meteorites, see the earlier

publications in this series (Marvin and Mason, 1980, 1982,

1984) and the computerized lists of publications from the

Antarctic Meteorite Bibliography, which may be obtained on

request from the Lunar and Planetary Institute, 3303 NASA

Road 1, Houston, Texas 77058. The Antarctic Meteorite

Bibliography references articles in Meteoritics, in the annual

proceedings of the Lunar and Planetary Science conferences

at Houston, the symposia on Antarctic Meteorites held by the

National Institute of Polar Research in Tokyo, and numerous

other sources.

Libraries of polished thin sections are maintained in

Washington, D.C., Houston, and Tokyo for the use of visitors

who wish to make microscopic examinations. To obtain

meteorite samples collected by parties sponsored by the

Japanese Antarctic Research Expeditions, or to use the thin

section library in Tokyo, contact Dr. Keizo Yanai, Curator, at

the National Institute of Polar Research, 9-10 Kaga 1-chome,

Itabashi-ku, Tokyo 173, Japan. To use the thin section library

at the Johnson Space Center at Houston, contact the Secretary

of the Meteorite Working Group at the address given above.

To use the thin section library at the National Museum of

Natural History, Smithsonian Institution, Washington, D.C.

20560, contact Roy S. Clarke, Jr., Curator.

Literature Cited

Marvin, Ursula B., and Brian Mason, editors

1980. Catalog of Antarctic Meteorites, 1977-1978. Smithsonian Contributions to the Earth Sciences, 23: 50 pages.

1982. Catalog of Meteorites from Victoria Land, Antarctica, 1978-1980.

Smithsonian Contributions to the Earth Sciences, 24: 97 pages.

1984. Field and Laboratory Investigations of Meteorites from Victoria

Land, Antarctica. Smithsonian Contributions to the Earth Sciences,

26: 138 pages.
NUMBER 28

Yamato M_ts

Belgica

2

Ellsworth Mts

Purgatory Peak (Dry Valleys)

t. Baldr

Man Hills

eckling Peak

lephant Moraine

McMurdo Station

Granite Harbor

Antarctica

KEY

Continental Boundary

Ice Shelf Border

Major Glaciers

Meteorite Find

180

500 km

FIGURE 1-1.—Outline map of Antarctica showing sites of meteorite finds. Chance discoveries of four meteorites

were made before deliberate searches began in 1973: Adelie Land, 1912, by Douglas Mawson; Lazarev, 1961,

by a Soviet Union field party; Thiel Mountains, 1962, and Neptune Mountains, 1964, by U.S. field teams. The

first concentration of different types of meteorites was found in 1969 on a blue icefield near the Yamato

Mountains by Japanese scientists, who have since found thousands of specimens in the regions of the Yamato

and Belgica mountains. ANSMET teams, working out of McMurdo Station, have found about 2000 specimens

at the Allan Hills and other sites from Darwin Camp to Elephant Moraine and in the Thiel Mountains region.

Individual meteorites have been found near Purgatory Peak, at Inland Forts in the Wright Dry Valley, and on

the Taylor Glacier. These last two sites lie a short distance south of Purgatory Peak, too close to be distinguished

on this map.
2. The 1982-1983 Antarctic Search for Meteorites

(ANSMET) Field Program

William A. C as sidy

Introduction

During December 1982 and January 1983, the ANSMET

program fielded three teams. One made reconnaissance

searches in the Thiel Mountains (85°15'S, 91°00/W)-Pecora

Escarpment (85°38'S, 68°42AW) area to locate previously

unknown stranding surfaces (see Chapter 3). The second team

carried out systematic searches and made meteorite recoveries

at known concentration sites such as the Allan Hills (76°43'S,

159°40'E) and Elephant Moraine (76°11'S, lSJ^O'E). The

third team remeasured and extended a previously set triangulation grid at the Allan Hills (see Chapter 4). The bilateral

collecting effort was designed to insure recoveries this season

and in future years. The Allan Hills party collected meteorites,

as had been expected, and the reconnaissance party located new

stranding surfaces, as had been hoped.

The Allan Hills-Elephant Moraine Excursion

Members of this group were Vagn F. Buchwald of the

Instituttet for Metallaere Danmarks Tekniske Hojskole at

Lyngby, Denmark, Tony Meunier of the United States

Geological Survey at Reston, Virginia, Carl Thompson, an

alpinist from Methuen, New Zealand, and the writer. Three of

us set out by helicopter for the Middle Western Icefield

(76°50'S, 158°26'E) where the lunar meteorite, ALHA81005,

had been found the year before. Because of a lack of surface

landmarks, however, we were unable to identify that icefield

with certainty and landed, instead, at the Allan Hills Far

Western Icefield (16°54'S, lSV^l'E). This site is beyond the

permitted limit for helicopter flights, but, at the time, we were

unsure of our location. When we landed, the helicopter

crewman hopped out and picked up a small meteorite, thereby

establishing it as a site where meteorites could be found. (We

believe he actually first saw the meteorite from the air and

directed the pilot down to a landing alongside the specimen.)

We had about half of our camp supplies with us and would

William A. Cassidy, Department of Geology and Planetary Science,

University of Pittsburgh, Pittsburgh, Pennsylvania 15260.

have been able to stay, but we could not establish radio

communications with McMurdo Station, and so we had to

return, leaving our equipment and supplies at the site. Two

days later we had another opportunity, and this time we

succeeded in making radio contact with McMurdo and were

allowed to stay.

Vagn Buchwald remained in McMurdo temporarily and

traveled as a passenger on a helicopter run to the head of the

Taylor Glacier. Walking around the landing site, he was both

startled and highly pleased to pick up a meteorite he found

lying on the glacier ice. Thus, the field season for this group

began with two accidental discoveries. Meanwhile, at the Far

Western Icefield we were finding that our accidental discovery

there had placed us on a very large area of exposed ice with

many meteorite specimens scattered on its surface.

The Far Western Icefield is a large, roughly W-shaped patch

of ice about 75 km west of Allan Hills (Figure 2-1). Satellite

photos show no areas of exposed ice farther west than this

one. This site has a significant advantage in common with the

Near and Middle Western Icefields, in that there is no source

of terrestrial rocks upstream of it. Therefore, any rock found

on its surface must be a meteorite. It appears to lie generally

upstream of the Allan Hills Main Icefield. If so, any meteorites

falling onto this surface, or being exposed here by ice ablation,

should be transported to the Main Icefield over a period of

time that would be measured by the horizontal flow rate of the

ice. One would expect specimens recovered here to have

younger terrestrial ages than those located closer to the Allan

Hills barrier; one would expect also a more sparse distribution

of specimens this far from the Allan Hills (cf. Whillans and

Cassidy, 1983).

In the several weeks available we could not cover the entire

surface of this large patch of bare ice, so we concentrated on

its southeastern end and the central exposure near our campsite.

We recovered 45 specimens in all, establishing the Far Western

Icefield as a productive meteorite stranding surface. Among

the specimens recovered was a walnut-sized meteorite "caught

in the act" of weathering out of the underlying ice: a minor

part of the meteorite was already exposed, but most of it was
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2-1.—Landsat photomap showing our field traverses, all meteorite stranding surfaces mentioned in this

article, and the locations of six reference points determined by satellite Doppler positioning. (Illustration taken

from 1972 NASA ERTS image E-l 128-28293-7, near infra-red band.)

embedded in the ice. The significance of this occurrence and

our treatment of the sample are described by Gow and Cassidy

(Chapter 10).

The Far Western Icefield is so far from the Transantarctic

Mountains that the only visible peak is Mt. Brooke in the

Convoy Range, and this can be seen only from certain vantage

points. Mapping of ice exposures and meteorite specimens is

a problem here because reference points cannot be established

by triangulation, and fixed points cannot be established because

the ice is moving. Fortunately we had arranged the loan of two

Magnavox model MX 1502 geoceivers from the U.S. Bureau

of Land Management; one was with the Thiel Mountains party

and we had the other. With these instruments we were able to

locate five points to use as references for mapping our

meteorite finds. All of the five will be valuable as reference

points for future finds, and three of them are precise enough

to be useful in measuring ice flow vectors in this part of the

East Antarctic Ice Sheet (see Table 2-1).

After using all the time we originally planned to devote to

systematic searching on the Middle Western Icefield, we

traversed eastward to John Annexstad's camp at the Main

Icefield. Carl Thompson's snowmobile was running on only

one cylinder at that time, so Tony Meunier and I each had to

draw three loaded Nansen sledges behind our snowmobiles.

We noticed very little difference between pulling two and

pulling three sledges, and it is now a routine procedure to draw

three sledges behind one snowmobile whenever that arrangement seems most convenient.
NUMBER 28

TABLE 2-1.—Best determinations of six geoceiver stations used in mapping meteorite finds. Locations and

elevations of six stations were determined using satellite Doppler positioning procedures. Raw data determined

in the field were refined later, using standardized computer programs for this purpose to arrive at the

post-processed data given here. Stations 0100-0104 are located at the Far Western Allan Hills Icefield, and

Station 0105 was located at our campsite at Elephant Moraine (Figure 2-1).

Station Number

0100

0101

0102

0103*

0104*

0105f

Latitude S

76°54'09.520"

76°57'46.861"

76°59'27.417"

77°02'50.954"

77°02'24.614"

76°17'34.910"

Longitude E

157°01'26.511"

156°54'40.164"

156°53'46.806"

157° 11'00.270"

157°15'33.896"

157°20'04.944"

Elevation (m)

2117.54

2145.01

2190.95

2163.50

2142.87

2022.33

Estimated error (in m)

1.5

2

2

5-10

5-10

10

*Reference oscillator frequency offset was abnormally high but stable; data are good but a larger error is

assigned.

f Broadcast solution (e.g., field data) not post-processed. Latitude and Longitude are referenced to the Naval

Weapons Laboratory 10D system (Jenkins and Leroy, 1979).

Carl had a replacement machine waiting for him at John's

camp, and we were joined there by Vagn Buchwald. We left

for Elephant Moraine two days later, as a party of four. The

traverse to a campsite at the far end of Elephant Moraine took

exactly 11 hours, including about an hour of searching for the

feature once we had arrived within a few miles of where we

knew it to be.

During a week at Elephant Moraine, we collected 18

specimens and left the site, confident that more fragments will

be recovered there in the future. High winds had prevented any

but rather random reconnaissance searches, and, in areas where

random searches give good recovery rates, systematic searching has always yielded many more specimens. During our one

day of relatively good weather at Elephant Moraine we

accomplished a round trip of 120 km, on which we visited

some of the extensive ice exposures due west of Elephant

Moraine (see photomap, Figure 2-1), and an isolated exposure

to the northwest. Random-path searching at the latter site

yielded two meteorites. As our four snowmobiles had covered

a cumulative distance of 64 km, this seemed to be a low rate

of discovery.

Because the weather had been consistently poor, and it was

getting late in the season, we decided to return to the Allan

Hills at the first opportunity. This came on 19 January. At 3:00

P.M. that day the wind dropped to 15 knots, so we broke camp

and left by 7:00 P.M. The return to Annexstad's camp took only

seven-and-one-half hours, despite steadily rising winds. These,

combined with cold temperatures due to the lower sun angle

during the night, stressed us more than I would have preferred,

but the trip was made without incident. We were interested to

find that we could easily follow our outward tracks made a

week earlier, not because they were pressed into the snow but

because they were now standing up several centimeters in

relief, having offered some resistance to the erosive effects of

the wind during the intervening week.

Results and Discussion

During the 1982-1983 field season unforeseen circumstances played a larger part in our results than in earlier years.

Initially we landed at the wrong ice exposure west of the Allan

Hills and discovered a previously unsuspected meteorite

stranding surface. We had visited this site briefly by helicopter

during the 1977-1978 season but had not found meteorites.

We probably never would have returned to it had it not been

for this lucky accident. Unforeseen also, however, was the

spate of days with high winds, which greatly reduced our

operating efficiency and turned our planned days of systematic

searching at Elephant Moraine into days of reconnaissance

trips, mostly near our field camp. In retrospect, these two

circumstances may have offset one another.

Finally, by sheer coincidence we were able to borrow

geoceivers for the very field season during which a put-in by

mistake at an unplanned location left us at a site where we

could benefit most from having a geoceiver orientation

capability. If the effects of the first two factors offset each

other, then this one gave us a distinct advantage.

The Whillans and Cassidy (1983) model for forming

meteorite concentrations at a barrier such as the Allan Hills

describes three mechanisms that may operate simultaneously:

the direct fall of meteorites onto an exposed ice ablation

surface, weathering out of meteorites that fell upstream and

were transported at various depths to the ice ablation surface,

and, once they emerged on that surface, ice-flow crowding of

both sets of specimens toward the barrier. Given a constant

infall rate of meteorites through time, and equal age for all

parts of an ablation surface (and, for the moment, disregarding

the crowding effect), all parts of the ablation surface should

have a constant density of meteorites that fell directly onto

that surface. Similarly, if ancient ice is being exposed by

ablation close to the barrier at the same rate that less ancient

ice is being exposed farther from the barrier, then the

contribution of transported meteorites also should be constant.
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Thus, any gradient in frequency of occurrence of meteorites

on different parts of an ablation surface could be attributable

only to the crowding effect, and this effect should act to

increase the frequency of meteorite occurrences toward the

barrier. Is such an increase observed? Because pairing

estimates are so uncertain, it is difficult to judge in quantitative

terms whether or not a regular increase in numbers of

meteorites does occur as one traverses eastward from the Far

Western Ice Field, over the Middle Western and Near Western

Icefields, to the Main Icefield at the foot of the Allan Hills.

Qualitatively, however, I can see no such variation, except

within the Main Icefield itself. There, the frequency of

meteorite occurrences is much higher on the ultimate

downstream section of the ablation surface, below the step

feature and closer to the barrier, than it is above the step feature.

This suggests the possibility that the three icefields to the west

actually are not located on a direct flowline toward the

stranding surface at the Main Icefield. Future remeasurements

of our geoceiver stations at the Far Western Icefield should

help to resolve this question, since the ice will have moved in

the interval.

Literature Cited

Jenkins, R.E., and C.F. Leroy

1979. "Broadcast" versus "Precise" Ephemeris-Apples and Oranges.

Proceedings of the Second International Geodetic Symposium on

Satellite Doppler Positioning (Austin, Texas, Jan 1979). Austin:

University of Texas Press.

Whillans, I.M., and W.A. Cassidy

1983. Catch a Falling Star: Meteorites and Old Ice. Science, 222:55-57.
3. The Expedition to the Thiel Mountains

and Pecora Escarpment, 1982-1983

John W. Schutt

Reconnaissance by C-130 Hercules

Two weeks of waiting in McMurdo at the end of the

1981-1982 season for aircraft availability and flying weather

were over. William Cassidy and I were aboard a ski-equipped

C-130 Hercules approaching the Thiel Mountains for a

bird's-eye view of icefields selected as having a good

probability of significant meteorite concentrations. Cassidy had

looked at hundreds of aerial photographs of the Transantarctic

Mountains, searching for expanses of ice with characteristics

similar to those with known meteorite concentrations in

southern Victoria Land. In West Antarctica, several areas in

the Thiel Mountains region and at the Pecora Escarpment, 160

km to the east, appeared favorable (Figure 3-1). Two fragments

of a pallasite had been found on blue ice in the Thiel Mountains

in 1961 (Ford and Tabor, 1971). Could they signify a large

meteorite concentration?

As the plane flew low over the Davies Escarpment we could

see ice gleaming below. We passed over the precipitous Bermel

Escarpment for a look at the icefields along the eastern side

of the Thiel Mountains and then on to the Moulton Escarpment.

Our excitement grew as we viewed these icefields. They did

indeed have features in common with the concentration sites

at the Allan Hills, Elephant Moraine, and Reckling Moraine.

The aircraft turned from the Thiel Mountains, heading eastward

for the Pecora Escarpment. Our excitement peaked as we

circled low over these icefields and they, too, looked

promising. Before leaving Antarctica we made plans to return

to the Thiel Mountains and Pecora Escarpment for a

reconnaissance traverse the following field season.

The Thiel Mountains-Pecora Escarpment Field Season

The field party of 1982-1983 consisted of Richard Crane,

of the United States Navy, Urs Krahenbuhl, of the University

of Bern, Switzerland, Louis Rancitelli, of Battelle Memorial

Institute at Columbus, Ohio, and the writer. Our party spent

John W. Schutt, Department of Geology and Planetary Sciences,

University of Pittsburgh, Pittsburgh, Pennsylvania, 15260.

thirty-five days in the field traveling roughly 1250 km on

snowmobiles.

On 13 December 1982 we flew over the Thiel Mountains

area to locate a landing site and to off-load equipment and

drums of snowmobile fuel. We landed at 85°07'S, 88°02'W,

approximately 23 km east of the Ford Massif. Two days later

we flew a second mission to drop fuel at two points along our

intended route and to put our party into the field.

Our first objective was a search of the icefields east of Mt.

Walcott and Mt. Wrather in the southern Thiel Mountains,

where the pallasite had been found (Figure 3-2). We discovered

no meteorites there. We then proceeded to the Pecora

Escarpment, a traverse of nearly 200 km requiring three days.

The Pecora Escarpment is a rocky mountainside, approximately 23 km long. It trends SW-NE and forms an absolute

barrier to ice flow. Roughly 125 square km of ice is exposed

upstream (Figure 3-3). Several less extensive icefields associated with ice escarpments are present within a radius of about

50 km. Upon arriving at the Pecora Escarpment we found snow

from recent storms covering a considerable area of the icefield.

Nevertheless, we began finding meteorites there soon after

beginning our search. Two days of high katabatic winds

interrupted our reconnaissance, but the winds removed much

of the snow and allowed us to search more effectively. We

found meteorites in greater numbers as we worked our way

toward the southwest end of the Pecora Escarpment. Many of

the specimens lay upstream of the rock barrier, as would be

expected. However, many others were found on ice that appears

to be downstream of the absolute barrier to ice flow; this has

not yet been explained. From the icefields in the immediate

vicinity of the Pecora Escarpment, we recovered 32 meteorite

specimens and took one sample of ice to be used for age

determination and ice chemistry studies. Because time did not

allow for both thorough searching and collection, we left at

least 50 meteorites in the field to be picked up in future seasons.

We did not explore ice patches outside the immediate vicinity

of the Pecora Escarpment, where we hope that additional

meteorites will be found.

Once we had determined that a significant meteorite
10 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

LOCATION DIAGRAM

30° WEST 0° EAST 30°

60° 60°

90°

120

120°

150° WEST 180° EAST 150°

FIGURE 3-1.—Location of the Thiel Mountains-Pecora Escarpment Region,

West Antarctica.

concentration existed at the Pecora Escarpment and that

systematic searching would be required there, we resumed our

reconnaissance traverse. Our next objective was the Davies

Escarpment, 160 km to the west. We followed our outward

trail back for a distance, then broke off and headed for Lewis

Nunatak, near the southern end of the Davies Escarpment.

Extending southward from the Thiel Mountains nearly 55 km,

the Davies Escarpment presents no absolute barrier to ice flow.

Ice cliffs and heavily crevassed areas are common along its

length with only a couple of small, isolated rock exposures.

Blue ice areas are of limited extent there and are present only

at the base of the escarpment (Figure 3-4).

Upon reaching the Davies Escarpment we found considerable snow on the icefields; however, there was sufficient

exposure to determine the extent of any meteorite concentrations. Our search of icefields along the Davies Escarpment

yielded seven meteorite specimens. We found no meteorites

on the small ice patches near Lewis Nunatak, but we picked

up one specimen on the ice approximately 8 km SSW of Lewis

Nunatak and six specimens during a thorough search of the

largest and northernmost icefield. We concluded that large

meteorite concentrations are not present in the vicinity of the

Davies Escarpment.

Proceeding from the Davies Escarpment, we traversed to the

Moulton Escarpment, an isolated nunatak 15 km west of the

Ford Massif. This east-west trending escarpment is approximately 20 km in length. A bedrock ridge standing above the

ice cap forms an apparent absolute barrier to ice flow along 7

km of the escarpment. At least seven distinct bouldery,

ice-cored moraines, with no exposed bedrock, are situated

below the escarpment (Figure 3-5).

Conventional thought on meteorite concentrations dictates

that the icefields upstream of a bedrock barrier should have the

greatest potential as stranding surfaces. Our first search

upstream at the Moulton Escarpment resulted in no meteorite

finds. A search of the second most likely area, 6 km east of

Chastain Peak, produced only one specimen. After our

successes at the Pecora and Davies escarpments, we had felt

confident of success at the Moulton Escarpment as well, and

were disappointed by the absence of any concentrations. We

expected the ice downstream of the bedrock to lack meteorites,

and we probably would not have visited that area except that

we had to cross it to reach our air drop of fuel. On the last trip

to the drop site, we spotted a small meteorite, distinguished

by its anomalous shape, lying amongst the abundant dark-gray

and black terrestrial rocks. We returned the next day in better

weather and lighting conditions. We found no additional

specimens at the easternmost ice-cored moraine, but, as we

moved southward past the moraine, we found nine meteorites

concentrated in a small area between the moraine and the

escarpment (Figure 3-6). We recovered a total of 11 meteorite

specimens from the Moulton Escarpment icefields.

Our party found three new meteorite concentration sites and

recovered a total of 50 specimens as a result of reconnaissance

searches of the Pecora, Davies, and Moulton escarpments.

Forty-two of the specimens are classified as ordinary

chondrites, seven as achondrites, and one as a carbonaceous

chondrite (see Table 3-1).

The meteorite concentration at the Moulton Escarpment is

unusual in that all meteorites, except one, were located on ice

that is apparently downstream of an absolute barrier to ice flow.

We also found meteorites on what may be downstream ice at

the Pecora Escarpment. The discovery of these "unusual"

concentrations, which contradict previous experience and

TABLE 3-1.—Classification of meteorite specimens recovered from the Thiel

Mountains/Pecora Escarpment region, 1982-1983. (See Antarctic Meteorite

Newsletter, 6(2), 7(1), 7(2).)

Location

Pecora

Escarpment

Davies

Escarpment

Moulton

Escarpment

Total

Ordinary

chondrite

26

6

10

42

Classification

Carbonaceous

chondrite

1

0

0

1

Achondrite

5

1

1

7

Total

32

7

11

50
NUMBER 28

11

FIGURE 3-2.—Route of the 1982-1983 reconnaissance traverse in the Thiel Mountains-Pecora Escarpment region.

FIGURE 3-3.—Camp near the base of Mount Wrather, Thiel Mountains.
12 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 3-4.—Aerial view looking southward over Pecora Escarpment. The large icefield, covering about 125

square km upstream (south) of the barrier yielded an abundance of meteorite specimens (dots), but specimens

were also found on smaller icefields downstream of the Escarpment in the vicinity of Ludlow Rock and west

of Damschroder Rock.

conventional thought on the concentration mechanism, have

increased the prospects for finding concentrations in areas that

previously would not have been searched.

NOTE: A Magnavox MX-1502 Satellite Surveyor, on loan

from the U.S. Bureau of Land Management, was used to

determine the geodetic positions of several meteorites (Figure

3-7) at the Pecora Escarpment. Doppler base stations were

established on Lulow Rock at the Pecora Escarpment and at

Chastain Peak (Figure 3-8) at the Moulton Escarpment. These

data have been used by the U.S.G.S. to improve the WGS-72

survey net in Antarctica.

Literature Cited

Antarctic Meteorite Newsletter, 6(2), August 1983.

Antarctic Meteorite Newsletter, 7(1), February 1984.

Antarctic Meteorite Newsletter, 7(2), July 1984.

Ford, A.B., and R.W. Tabor

1971. The Thiel Mountains Pallasite. United States Geological Survey

Professional Paper, 750-D. Washington, D.C.: United States

Government Printing Office.
NUMBER 28 13

FIGURE 3-5.—Aerial view looking southward along the Da vies Escarpment (right center). Dots indicate locations

of the seven meteorite specimens found in this area: six on the northernmost icefields at the foot of the

Escarpment, and one about 8 km SSW of Lewis Nunatak.
14

SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 3-6.—Aerial view looking southward over the Moulton Escarpment with Chastain Peak near the eastern end.
NUMBER 28 15

;,.-•*#*** •

FIGURE 3-7.—Satellite surveying of meteorite locations at the Pecora Escarpment.

FIGURE 3-8.—Satellite surveying at Chastain Peak survey point in the Moulton Escarpment.
4. Extension of the Allan Hills Triangulation

Network System

John O. Annexstad and Kristine M. Annexstad

The Allan Hills Icefield was spanned by a triangulation

network of 20 stations in 1978 (Nishio and Annexstad, 1979).

Station locations in relation to the Allan Hills and its associated

icefields are shown in Figure 4-1. The network crosses the

region of highest meteorite concentration represented by the

dotted area. The stations were resurveyed in 1979 and 1981

and the results showed that ice movement was generally from

west to east, it decreased in velocity as the Allan Hills were

approached, and the ice surface ablated at an average rate of

about 5 cm per year (Nishio and Annexstad, 1980; Annexstad,

1983; Schultz and Annexstad, 1984).

During the 1982/1983 austral summer field season the

authors extended the original triangulation network from the

Allan Hills Main Icefield to the Near Western Icefield (Figure

4-2) and attempted to locate station positions with an

astronomical theodolite. Inclement weather forced an early end

to the field season and frustrated attempts to accurately survey

the newly established stations.

The network as it now appears is shown in Figure 4-3

extending in a westerly direction from the baseline (Stations 1

and 2). Stations 25 to 38 were added to the original line. Station

numbers are not sequential because the strain flower (Stations

21-24) was established after the initial survey of the original

network (Stations 1-20).

Ablation was measured at each station of the original

network prior to installing the line extension. This measurement consists of obtaining the distance to 0.1 cm from the top

of the pole to the surface of the ice. An east side and west side

reading is taken at each station and the measurements averaged,

because the ice surface can be quite uneven near the base of

the poles.

Table 4-1 lists the annual rates of ablation from 1978 to

1982 with the four year average and standard deviation (from

Annexstad, 1983). From this table it can be seen that the rate

of ablation varies from year to year and from station to station.

John O. Annexstad, NASA Johnson Space Center, Houston, Texas

77058. Kristine M. Annexstad, Frank Welch and Associates, Dallas,

Texas 75205.

Although sublimation plays an important part in the process

of ablation, Annexstad (1983) has shown that the abrasive

action of blowing ice crystals is also a contributing factor.

The network was extended from Station 20 to the visible

part of the Near Western Icefield as determined by binocular

observations. The eastern portion of the Near Western Icefield,

as viewed from Station 20, is a small ice patch about 1 km

wide situated below the crest of a rather prominent firn field.

Therefore, the extension line was constructed as two legs, one

leg from Station 20 and one leg about a kilometer south of

Station 20, each of which intercepted one edge of the visible

portion of the eastern section of the Near Western Icefield.

Stations 20-36 (even numbered) were positioned about 1.5

km apart unless a closer spacing was needed for visual contact.

Each station was placed so that a lower numbered and a higher

numbered station were visible with binoculars.

Stations 25 to 37 were positioned along a line 1 km to the

south of the even-numbered leg. Each individual station was

placed as close as possible to a point on the perpendicular

bisecting the line between two even-numbered stations and

visible from a lower and higher numbered station on the same

leg. This method of positioning ensures that the surveyor at

each station has clear visibility of at least three other stations.

Each station consists of a 3 m bamboo pole placed into a 7.5

cm diameter hole drilled 70-100 cm deep in the ice or firn.

The base of the pole is wrapped in a layer of fiberglass

insulation to decrease ablation effects from conduction and to

ease pole removal for the survey. The poles were numbered

appropriately and a red trail flag attached 2-3 centimeters

below the top. Measurements were taken of the depth of the

hole and the height of the pole from the surface.

Figure 4-4 shows one of us (KMA) using a fiberglass-bodied

drill to establish one of the stations. The drill is operated by

hand and the operator is protected from the prevailing winds

by a snowmobile-mounted, triangularly shaped windbreak. The

fiberglass-bodied drill is considerably easier to use than the

steel SIPRE drill, formerly used on this project, but its lack of

weight requires some downward pressure by the operator.

Numerous attempts were made to establish station positions

17
18 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

-TfX'S

EASTERN ANTARCTIC

ICE SHEET

\ BLUE id, ' '***''

ANTARCTIC METEORITE DISCOVERY AREA

FIGURE 4-1.—The original triangulation network across the Allan Hills Main Icefield.

and distances from known points by triangulation survey

methods. A Wild T-2 theodolite and the triangular windbreak

pictured in Figure 4-4 were used in these attempts. Unfortunately, the Antarctic weather did not cooperate and only two

stations (20 and 19) were successfully occupied. It should be

noted that conditions varied between whiteouts and severe

blowing snow, which made theodolite observations all but

impossible in this area. The network extension is constructed

primarily in firn so that even moderate winds will obscure the

survey targets with blowing snow.

The distances between Stations 20-38, shown in Figure 4-1,

are snowmobile odometer readings, because the triangulation
NUMBER 28 19

ALLAN HILLS ICEFIELD

\

North

Battlements

Nunatak

Main

Near

Western

Middle

Western

o

o

, 10 km

FIGURE 4-2.—The four icefields lying west of the Allan Hills.

survey was not completed. These distances are subject to the

errors due to surface undulations of the firn and the notorious

inaccuracies of snowmobile odometers.

Although a precise determination of position and movement

of the stations must await future surveys, some visual

observations of surface conditions were noted at the Near

Western Icefield. A wave-like step feature at the eastern edge

of the Near Western Icefield is the most prominent topographic

feature. This step feature resembles the one in the immediate

vicinity of the Allan Hills that Yanai et al. (1978) described

as a monocline. On the eastern slope of the step the blue ice

has reached the surface and the high winds in that area keep it

free of snow. The ice surface is interlaced with small crevasses

and tensional cracks, which are common features in blue ice

areas. The general alignment of the crevasses is with the long

axis perpendicular to a northeast ice flow direction. The

crevasse patterns indicate that the surface ice in this vicinity

will bypass the Allan Hills Main Icefield, which lies to the east.
20 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 4-3.—The triangulation network with recent extensions: the strain flower (Stations 21 to 24) and the

southwest extension (Stations 25-38).

In a description of the four icefields that are upstream of the

Allan Hills, Schutt et al. (1983) suggested that they are all

interconnected and part of the main Allan Hills Icefield. The

locations of these ice fields are shown in Figure 4-2 relative

to the Allan Hills and Battlements Nunatak (Annexstad, 1983).

The assumption that the four icefields are interconnected may

be a premature guess if the direction of motion indicated by

crevasse alignment at the Near Western Icefield is correct. If

the icefields are interconnected, it should follow that surface

crevasse patterns should indicate an easterly flow direction,

toward the Allan Hills. A positive determination of the

direction of flow and its velocity must await further survey

data. Until those data are available it does appear that the

meteorite concentration areas in the main Allan Hills Icefield

represent the convergence of a diverse set of flow patterns

emanating from a number of widely spaced sources.

Literature Cited

Annexstad, J. O.

1983. Meteorite Concentrations and Glaciological Parameters in the Allan

Hills Icefield, Victoria Land, Antarctica. Doctoral dissertation,

Doktor der Naturwissenschaft, Johannes Gutenberg Universitat,

Mainz, Federal Republic of Germany.

Nishio, F., and J. O. Annexstad

1979. Glaciological Survey in the Bare Ice Area near the Allan Hills in

Victoria Land, Antarctica. Memoirs of the National Institute of Polar

Research (Japan), special issue, 15:13-23.

1980. Studies on the Ice Flow in the Bare Ice Area near the Allan Hills

in Victoria Land, Antarctica. Memoirs of the National Institute of

Polar Research (Japan), special issue, 17:1—13.

Schultz, L., and J. O. Annexstad

1984. Ablation and Ice Movement at the Allan Hills Main Icefield between

1978 and 1981. In U.B. Marvin and B. Mason, editors, Field and

Laboratory Investigations of Meteorites from Victoria Land,

Antarctica. Smithsonian Contributions to the Earth Sciences,

26:17-22.

Schutt, J.W., W.A. Cassidy, G. Crozaz, R.F. Fudali, and U.B. Marvin

1983. Results of Meteorite Search and Recovery Activities in the Vicinity

of the Allan Hills, Antarctica, Dec. 1981-Jan. 1982. In R.L. Oliver,

P.R. James, and J.B. Jago, editors, Antarctic Earth Science.

Canberra: Australian Academy of Science.

Yanai, K., W.A. Cassidy, M. Funaki, and B.P. Glass

1978. Meteorite Recoveries in Antarctica During Field Season 1977-78.

Proceedings of the 9th Lunar and Planetary Science Conference,

pages 977-987.
NUMBER 28 21

TABLE 4-1.—Rates of ablation (-) and accumulation (+) measured in centimeters per year at survey stations

on the Allan Hills Icefield.

Station

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

1978-1979

-2. 2

-2. 3

-1.1

-1.7

-2. 6

-3.8

-4. 3

-6. 6

-5. 7

-4. 5

-5.7

-7. 2

-5.8

-4.3

-5.4

-4.7

-3. 2

-1.8

-6.5

-5.8

-6. 1

-0. 5

1979-1980

+ 1.8

-0.9

-2.1

-2. 5

-2. 8

-1. 7

-2. 0

-3. 7

-2.7

-2.9

-6. 5

-2. 6

-2.1

-0.1

-3. 5

-4. 2

-1.1

-1. 3

-2. 6

-1.4

-3. 0

-3.7

1980-1981

-2.0

+ 18.1

+ 1.4

-2.8

+ 2.6

-1.9

-3.3

-5.7

-5.8

-5.1

-6.2

-4.3

-4.9

-1.6

-2.9

-3.5

-2.0

-1.7

-4.9

-2.8

-5.6

-4.8

1981-1982

+ 2.8

-2. 9

-0. 1

-3. 2

-0. 4

-1. 3

-4. 7

-0. 2

-7.1

-2. 4

-5.8

-4.8

-4. 2

-1.8

-7. 2

-5. 7

-2. 5

+ 0.4

+ 5.1

-8.4

-3.3

-5. 6

1978-1982

Average ± Std. Dev.

+ 0.1+2.6

+ 3.0±10.1

-0. 5 ±1.5

-2. 6 + 0.6

-0.8 ±2.5

-2.211. 1

-3. 6 ±1.2

-4.0 ±2.8

-5.3 ±1.9

-3.7 ±1.3

- 6.0 ± 0.4

-4.7 ±1.9

-4. 2 ±1.6

-2. 0 ±1.7

-4.8 ±2.0

-4. 5 ±0.9

-2.2 ±0.9

-1.1 ±1.0

-2.2 ±5.1

-4.6 ±3.1

-4.5 ±1.6

- 4.8 ± 0.8
22 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 4-4.—Kristine Annexstad drilling a station hole with the fiberglass-bodied drill. The triangular

windshield is attached to the snowmobile.
5. The Field Season in Victoria Land, 1983-1984

Robert F. Fudali and John W. Schutt

The 1983-1984 season marked the eighth consecutive year

of Antarctic Search for Meteorites fieldwork on the South Polar

Plateau. This ANSMET team was the largest single field party

to date, consisting of eight people equipped with eight

steel-cleated snowmobiles and 12 Nansen sleds. The team was

led by William A. Cassidy of the University of Pittsburgh.

Other participants were A.C. Hitch, of Ferndale, Washington,

K. Nishiizumi, of the University of California at San Diego,

Paul Pellas, of the Museum of Natural History in Paris, Ludolf

Schultz, Max Planck Institute for Chemistry in Mainz, West

Germany, Paul Sipiera, Harper College, Illinois, and the

authors.

Despite some annoying equipment malfunctions involving

the snowmobiles, Nansen sleds, and field radios, and two

potentially serious mishaps caused by a parachute that failed

to open during a fuel drop at Elephant Moraine, plus a bad

tent fire late in the season, our overall accomplishments rank

with the best of those of previous seasons. Our provisional field

count of meteorites, meteorite fragments, and possible

meteorites was 367, and 40 to 50 more small fragments were

not bagged individually. One iron meteorite was found in the

Wright Valley by a member of George Demon's University

of Maine field party and turned over to us at the end of the

season.

For the first time, many of the meteorite find locations were

determined using a theodolite and an electronic distance

measuring device. These locations were also determined

absolutely, with accuracy on the order of a few meters, by tying

them to geoceiver stations positioned at Elephant Moraine and

the Far Western Icefield the previous season by satellite

doppler tracking. This surveying equipment was also used to

emplace a series of survey stations between the Far Western

Icefield and the Main Icefield in the Allan Hills region. These

stations were tied to the previously established triangulation

network on the Main Icefield and to the geoceiver stations on

the Far Western Icefield. Gravity measurements were made at

Robert F. Fudali, Department of Mineral Sciences, National Museum

of Natural History, Smithsonian Institution, Washington, D.C. 20560.

John W. Schutt, Department of Geology and Planetary Sciences,

University of Pittsburgh, Pittsburgh, Pennsylvania 15260.

all these stations and tied to the previous gravity measurements

over the triangulation network (Fudali, 1982). The gravity data

are now sufficient to give us a general idea of the depth and

configuration of the ice/bedrock interface out to a distance of

70 km WSW of the Allan Hills. Finally, we collected large

blocks of ice from five icefields, using a power chain saw, for

a number of isotopic studies that we hope will lead to a better

understanding of the ice ages and ice dynamics in the collecting

areas.

Our original plan called for a Hercules C-130 put-in of our

party at the Far Western Icefield, 70 km WSW of the Allan

Hills, which we would search systematically and then move

to the Mid and Near Western Icefields for similar work. The

four separate blue icefields WSW of the Allan Hills have been

described in some detail by Fudali and Schutt (1984) and are

shown in Figure 4-2 (Chapter 4). However, C-130 reconnaissance flights were unable to find a suitable landing site

anywhere in the vicinity of the Far Western Field. The only

suitable landing site we found was in the vicinity of Griffin

and Outpost Nunataks, which held no promise of meteorites.

Under those circumstances, we decided to revise our plans and

devote a major effort to systematically searching Elephant

Moraine and its adjacent blue ice fields, and then to traverse

overland to the ice fields west of Allan Hill (Figure 5-1).

To find a suitable landing site for a ski-equipped C-130 on

the South Polar Plateau is an interesting task. The preferred

test is to drive the C-130 onto the snowfield under flying power

and observe the effects of this maneuver, both on the aircraft

and on the snow surface. Those of us who participated in such

reconnaissance flights can attest to the adrenalin-pumping

nature of such maneuvers. We commend C-130 Commander

Brian Rich and his crew for their competence and their "cool."

On 9 and 10 December, two C-130 flights put in our party,

equipment, and supplies, 60 km north of Elephant Moraine

(Figure 5-2). Strong katabatic winds made overland travel

difficult and, indeed, kept us tentbound at the landing site for

two days. We reached the moraine (Figure 5-3) on the morning

of 15 December.

We spent 13 days at Elephant Moraine, systematically

searching the blue ice fields, east, west, and south of the

moraine with snowmobile sweeps. We also spent considerable

23
24 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

* >

FIGURE 5-1.—Camps and route of the season's snowmobile traverse that logged 1250 km in 45 days.

time searching, on foot, within the moraine. Meteorites do

occur in the moraine and can be distinguished from the

terrestrial rock litter (Figure 5-4), but the bulk of the meteorites

were recovered from the blue ice surfaces, and it is questionable

whether persistent moraine searches on foot is a time-effective

way to recover Antarctic meteorites. We continued to find

meteorites on blue ice until the day we left and there are surely

additional meteorites on the icefields there. A total of 207 field

numbers were issued at Elephant Moraine, with provisional

field identifications as shown in Table 5-1.

On 26 December, a C-130 air drop at the moraine provided

us with a spectacular cratering experiment. One of the three

pallets failed to deploy its parachute and four 55-gallon drums

of fuel impacted the snow with undiminished velocity. All
NUMBER 28 25

FIGURE 5-2.—Unloading a ski-equipped C-130 Hercules near Griffin and

Outpost Nunataks.

FIGURE 5-3.—The southern part of Elephant Moraine, looking south.

four drums were breached by the impact but we managed to

salvage three of the four with minimal fuel loss. The fourth

drum provided us with 55 gallons of fuel-soaked snow in which

to burn our trash before breaking camp.

Elephant Moraine is an interesting feature that deserves

further study. It is unrelated to any bedrock outcrop and

consists of a complexly configured ice ridge littered with a thin

surface veneer of rocks of diverse sizes and types. Similar

moraines elsewhere in Antarctica have been assumed to signal

the presence of bedrock at shallow depth beneath them. The

meteorite concentration provides indirect evidence of a

subsurface, partial barrier to ice movement, but we have no

direct information on this postulated barrier.

The weather during the 15-28 December period was almost

entirely dominated by temperatures well below freezing and

strong katabatic winds. Nevertheless, on several occasions

liquid water was observed on the lee and sunny side of rock

surfaces in the moraine (Figure 5-5). Almost all Antarctic

meteorites show some weathering effects and many are badly

oxidized. Meteorite weathering has generally been regarded

as an extremely slow process on the Polar Plateau, characterized by only infrequent contact with liquid water on warm,

sunny, windless days. Our observations at Elephant Moraine

suggest that liquid water may be a more pervasive weathering

agent than previously supposed.

We departed Elephant Moraine on 29 December (Figure

5-6) and proceeded to the camp site of the 1982-1983 season

on the Far Western Icefield. Aside from the partial disintegration of one Nansen sled, carrying two 55-gallon drums of fuel,

this leg was made in two days without significant incident.

We did not intend to collect meteorites systematically at the

Far Western Icefield, as the field season was drawing to a close

and we had much else still to do. We were primarily interested

in collecting ice samples for isotopic studies, especially from

the site of a meteorite found embedded in the ice last year (see

Chapter 10), and in tying together the geoceiver stations

emplaced the previous season with a view toward extending

ground-surveyed stations from the Far Western Field all the

way to the Allan Hills network. At the expense of leaving a

number of observed but uncollected meteorites on the ice, we

achieved these goals. We could not, however, resist collecting

a few meteorites, including 76 individual fragments of a

carbonaceous chondrite (Figures 5-7 and 5-8) that Paul Pellas

caught sight of as we were proceeding toward the iceembedded meteorite site. These fragments appeared to be

entirely fresh and were scattered on both ice and snow surfaces,

leading us to believe we might be collecting a very recent fall.

26A1 measurements have subsequently shown this supposition

to be incorrect (W.A. Cassidy, personal communication).

On 6 January we broke camp and proceeded to the Middle

Western Icefield, putting in survey and gravity stations along

the way. We intended to systematically and thoroughly sweep

that entire icefield for meteorites but were hampered by high

winds during virtually our entire nine-day stay. In fact high

winds kept us tentbound for seven straight days. Nevertheless,

we did manage to collect a few meteorites and extend the

survey and gravity stations half way to the Near Western

Icefield before leaving for the Main Icefield.

On 14 January a bad tent fire resulted in burns to Paul

Sipiera's hands and face. He was evacuated by helicopter

within two hours and, upon landing at McMurdo, was put

directly on a C-130 flight to New Zealand. The same helicopter

returned Paul Pellas and Ludolf Schutz to McMurdo, leaving

five of us in the field.

On 16 January we moved camp for the last time, extending

survey and gravity stations to the Near Western Icefield and

then traversing directly to the Main Icefield for our final few

days. On the 17th a three-man crew from the British

Broadcasting Corporation joined us for several days of filming

and thereby severely curtailed our collecting activities. In just

a few hours of searching, however, we found 29 meteorites

on ice surfaces that have been searched and researched in past
26 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 5-4.—Small iron meteorite (dark and shiny) found among the rocks

of Elephant Moraine.

: « •

FIGURE 5-5.—Liquid water and icicle on the sun-facing side of a boulder in

Elephant Moraine.

FIGURE 5-7.—Paul Pellas and the first three carbonaceous chondrite fragments

found at the northernmost extension of a small strewnfield containing a total

of 56 fragments (see also Figure 5-8).

seasons. This probably reflects the fact that snow cover was

remarkable for its virtual absence on the Main Icefield, in

contrast to previous seasons. A few meteorites were also

incidentally picked up by a two-person party working to extend

the survey stations from the Near Western Field to the

triangulation network on the Main Field.

On 21 January, meteorites, ice blocks, and three team

members were flown to McMurdo. Three days later the last

two people were returned safely, bringing to a close what was

arguably the most ambitious ANSMET field season to date.

Our snowmobile odometers logged over 1250 km during 45

days on the Polar Plateau. In addition to the large number of

meteorites returned from five separate locations, an ice

sampling program was carried out, and survey and gravity

stations now extend from exposed bedrock at Allan Hills to the

Far Western Icefield.

Literature Cited

Fudali, Robert F.

1982. Gravity Measurements across the Allan Hills Main Meteorite

Collecting Area. Antarctic Journal of the United States, XVIII,

5:58-60.

Fudali, Robert F., and John W. Schutt

1984. The Field Season in Victoria Land, 1981-1982. In U.B. Marvin and

B. Mason, editors, Field and Laboratory Investigations of Meteorites

from Victoria Land, Antarctica. Smithsonian Contributions to the

Earth Sciences, 26:9-16.

FIGURE 5-6.—ANSMET on the move.
NUMBER 28 27

Table 5-1.—Tentative classification of meteorite specimens found at Elephant Moraine and the

Allan Hills icefields during the 1983-1984 season.

Specimens

Ordinary

chondrites

Carbonaceous

chondrites

Acondrites

Stony-Irons

Irons

Possible

meteorites

Total

Elephant

Moraine

179

4

12

1

3

8

207

Allan

Hills

Far West

7

76

83

Icefield

Allan

Hills

Mid West

31

2

2

35

Allan

Hills

Near West

13

13

Allan

Hills

Main

29

29

Total

259

82

14

1

3

8

367

2128

2126-5 through 56

2120

2126-4

I® 2126-1, 2,3

pinnacle s

FIGURE 5-8.—Sketch map of carbonaceous chondrite strewnfield of 56

fragments (field numbers 2126-1 to 2126-56) on the Allan Hills Far Western

Icefield. Numbers 2120 and 2128 are other types of meteorites in the same area.
6. Descriptions of Stony Meteorites

Brian Mason, Glenn J. MacPherson, Roberta Score,

Carol Schwarz, and Jeremy S. Delaney

This chapter provides descriptions of some of the individual

meteorite specimens collected during the 1982-1983 and

1983-1984 field seasons. The descriptions are based largely

on those published in the Antarctic Meteorite Newsletter, with

additional information as available. Also included here are

previously unpublished data on small specimens of special

interest from the 1978-1979 and 1981-1982 field seasons.

The Appendix contains a complete list of Antarctic meteorites

recovered to date, along with their type, weathering grade,

mass, etc. Specimens weighing less than 100 grams that do

not show distinctive features are listed in the Appendix, but

are not described in the text.

Descriptions are arranged according to meteorite classification. Within the chondrites the specimens are grouped

according to the Van Schmus and Wood (1967) classification,

and the descriptions follow the order of increasing petrographic

type.

The letter-number designations concur with guidelines

recommended by the Committee on Nomenclature of the

Meteoritical Society; each carries the following information:

location, e.g., ALH (Allan Hills); expedition and year, e.g.,

A81 (Expedition A, 1981); sample number, xxx (e.g., 213).

After 1981 the "A" preceding the year was dropped. The

original weight of the specimen is given to the nearest gram

(nearest 0.1 gram for specimens weighing less than 100 grams).

Chondrites

CLASS C2

FIGURES 6-1,6-2

ALHA81312 (0.7 g).—This small specimen (1.0 x 0.8 x 0.5

cm) was tentatively identified as a carbonaceous chondrite

from its exterior features, and this has been confirmed by

Brian Mason and Glenn J. MacPherson, Department of Mineral

Sciences, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. Roberta Score and Carol Schwarz,

North•op-Houston, Johnson Space Center, Houston, Texas, 77058.

Jeremy S. Delaney, Department of Mineral Sciences, American

Museum of Natural History, New York, N.Y. 10024.

examination of the thin section. The section shows several

small chondrules (maximum diameter 0.5 mm) and numerous

colorless mineral grains in a translucent brown to opaque black

matrix. McSween (personal communication) reports the

following modal analysis of this section (vol. %): matrix, 60.3;

monomineralic grains, 14.1; chondrules and plplymineralic

fragments, 22.8; inclusions, 2.8. Microprobe analyses show the

following wide ranges in composition for olivine and

pyroxene: olivine, Fa135, with a mean of Fa6; pyroxene

generally close to clinoenstatite in composition, but individual

grains range up to Fs31. Small refractory (spinel-rich)

inclusions are present, some of which contain pleochroic (deep

blue to colorless) hibonite.

ALH82100 (24.3 g).—Patches of fusion crust are preserved

mainly on one side of this small stone (3.5 x 3.5 x 2.5 cm).

Small submillimeter inclusions are visible on the exposed

interior surfaces. The stone is unfractured and one face has a

rough texture from weathering. The thin section shows

numerous small colorless grains (up to 0.3 mm) and irregular

aggregates (up to 0.6 mm, and mainly of olivine), and sparse

chondrules, in a black matrix that is translucent brown in

thinned areas. A few small spinel- and perovskite-bearing

refractory inclusions and spherules are present. Trace amounts

of nickel-iron and troilite occur as widely dispersed minute

grains. Microprobe analyses show olivine compositions in the

range Fa147, but most grains are iron-poor and the mean

composition is Fa5; pyroxene is rare, and only two grains of

clinoenstatite (Fs^) were analyzed. McSween (personal

communication) reports the following modal analysis of this

section (vol.%): matrix, 77.1; monomineralic grains, 7.5;

chondrules and polymineralic fragments, 13.9; inclusions, 1.5.

ALH82131 (1.0 g).—One small patch of blistery fusion crust

remains on this tiny specimen (1 x 1 x 0.5 cm). The exposed

underlying surface is black with a greenish tinge. The interior

is black and contains many submillimeter-size white inclusions. A green weathering rind extends approximately 1 mm

into the stone. The very small thin section shows a single

chondrule in a black (brown on thin edges) opaque matrix.

Microprobe analyses show that the matrix has the composition

29
30 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

ALH 83016 ,0

*°*% "

FIGURE 6-1.—C2 chondrites; note the blistery fusion crust on ALH83016.

characteristic of C2 chondrites. Clasts and inclusions are

largely replaced by green to brown phyllosilicate material.

Olivine in the chondrule is almost pure forsterite (FeO 0.3%;

CaO 0.3%-0.4%).

ALH83016 (4.1 g).—A brown to black fusion crust covers

part of this small stone (3 x 2 x 0.8 cm). The interior is black

with abundant irregular white inclusions and some chondrules.

The thin section shows a few poorly defined chondrules up to

1.8 mm across, consisting of granular or barred olivine with

minor polysynthetically twinned clinopyroxene. A few small

spinel-rich inclusions are present. The bulk of the meteorite

consists of translucent brown to opaque black matrix. Scattered

through the matrix are colorless, birefringent grains, mostly

olivine, up to 0.3 mm but usually less than 0.1 mm across.

Trace amounts of nickel-iron and sulfides are dispersed

throughout the section as minute grains. Well-preserved fusion

crust rims part of the section. Microprobe analyses show that

olivine varies widely in composition, ranging from Fa ^ to

Fa30 (with a mean of Fa n ); it also has a notable chromium

content, 0.1-0.5 weight percent Cr2O3. Pyroxene is generally

close to clinoenstatite in composition. McSween (personal

communication) reports the following modal analysis of this

section (vol.%): matrix, 65.6; monomineralic grains, 7.1;

chondrules and polymineralic fragments, 22.6; inclusions, 3.7.

ALH83100 (2293 g).—Since the initial description of this

stone, many other specimens have been paired with it (e.g., see

Antarctic Meteorite Newsletter, 8(2), and the cumulative

weight for 55 pieces is 2293 g. ALH83100 itself is an angular

fragment, and is so highly fractured that several pieces fell off

during handling. The surface is dull black with a few barely

discernible clasts or chondrules. White "evaporite" deposits are

present locally; these are apparently weathering products

formed in the Antarctic, but they only became visible in the

receiving laboratory as water in the interior of the meteorite

worked its way to the surface carrying soluble salts along with

it. The thin section shows a large number of clasts (up to 1
NUMBER 28 31

FIGURE 6-2.—Photomicrographs of thin sections of C2 chondrites (each field of view is 3 x 2 mm): a,

ALHA81312; b, ALH83100; c, EET83226; d, EET83250. Irregular aggregates, grains, and rare chondrules,

mainly of olivine (white to gray) in translucent to opaque matrix (black).

mm across) and mineral grains, and a few chondrules, in a dark

matrix. A little (about 1%) sulfide is present as minute grains,

some of which are concentrated at the margins of chondrules.

Nickel-iron occurs in trace amounts, some as small spherules.

The clasts, inclusions, and most of the mineral grains consist

of phyllosilicate and, in many places, calcite, that are probably

alteration products of the original phases. Microprobe analyses

shows that a few preserved primary grains are forsteritic

olivine.

ALH83102 (1786 g).—This meteorite consists of 20 or

more pieces; only two of the larger pieces have been examined

to date. Both pieces are extensively fractured and extremely

friable. Small patches of fusion crust are present. White

evaporite deposits (see above) are present on both interior and

exterior surfaces. Small white inclusions are visible in a

greenish black to black matrix that locally shows signs of heavy

oxidation. The thin sections show that the two fragments are

identical. Both are intensely altered, with the matrix, inclusions, and chondrules being almost completely replaced by

iron-rich phyllosilicates, calcite, and iron oxides. The matrix

is opaque and black except where the sections are unusually

thin. Olivine grains are sporadically preserved, with compositions that are mostly Fa^ , although some range up to Fa42.

One small spinel-rich refractory spherule was found, in which

the spinel is nearly pure MgAl2O4. No other primary phases

were found in this spherule.

This meteorite can confidently be paired with ALH83100,

because of the identical and unusual petrographic features of

both specimens and because of their geographic proximity on

the ice field where they were found (see Chapter 5).

EET83224 (8.6 g).—A dull and fractured fusion crust covers

about one-quarter of this small specimen (2.5 x 2.5 x 1.5 cm).
32 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Some of the uncrusted surface is jet black, but in places it has

weathered to a brown color. Chondrules and small irregular

white inclusions are visible in the jet black interior. The thin

section shows a few chondrules (up to 0.8 mm in diameter),

small (0.1 mm or less), colorless, and birefringent grains

(mostly olivine), and what appear to be chondrule or clast

fragments, all in a transparent brown to opaque black matrix.

Chondrules consist mostly of granular olivine, but a few have

minor polysynthetically twinned clinopyroxene as well. A few

small spinel-bearing refractory inclusions are present. Accessory nickel-iron and trace amounts of sulfide are dispersed

throughout the section as minute grains. Microprobe analyses

gave the following compositions: olivine ranges from Fa0 2 to

Fa41, with a mean of Fag; pyroxene is generally near enstatite

in composition (FeO 0.4%-1.0%). McSween (personal communication) reports the following modal analysis of this section

(vol.%): matrix, 63.8; monomineralic grains, 12.4; chondrules

and polymineralic fragments, 21.3; inclusions, 2.5.

EET83226 (33.1 g).—No fusion crust remains on this

angular fragment (4 x 2.5 x 3 cm). The exposed surface is jet

black with a granular texture and shows abundant chondrules

and inclusions. The thin section shows abundant small

chondrules, averaging about 0.3 mm in diameter, and numerous

mineral aggregates and mineral grains, set in a moderate

amount of dark brown to black opaque matrix. Chondrule types

include granular and barred olivine, some of which contain

pale brown and partly devitrified glass. Accessory amounts of

finely dispersed nickel-iron and sulfide are present. Microprobe

analyses show that much of the olivine is near forsterite in

composition, but occasional iron-rich grains are present (the

overall range is Fao5.69, with a mean of Fa12). Pyroxene grains

are rare; their composition range is Fs0 ^Q . McSween (personal

communication) reports the following modal analysis of this

section (vol.%): matrix, 39.6; monomineralic grains, 14.5;

chondrules and polymineralic fragments, 36.1; inclusions, 9.8.

EET83250 (11.5 g).—This specimen broke into many

fragments during transport from Antarctica. Both fusion crust

and white evaporite deposits cover much of the exterior

surface. Interior surfaces are black and speckled with white

inclusions. In thin section only a few chondrules and chondrule

fragments are seen; the bulk of the meteorite consists of brown

to black semi-opaque matrix, enclosing numerous small (0.1

mm and less), colorless, birefringent grains, mostly olivine. A

few small spinel-rich inclusions are present. The matrix also

contains trace amounts of finely dispersed nickel-iron and

sulfides. Well-preserved fusion crust rims part of the section.

Microprobe analyses show most of the olivine is close to

forsterite in composition, with a few iron-rich grains (the range

is FaQ 3_22, with a mean of Fa4). Pyroxene grains are rare; their

composition range is Fs2.14. McSween (personal communication) reports the following modal analysis of this section

(vol.%): matrix, 71.2; monomineralic grains, 14.5; chondrules

and polymineralic fragments, 12.1; inclusions, 2.2.

CLASS C3

FIGURES 6-3,6-4

ALHA81258 (1.1 g).—This small stone (1 x 1 x 0.5 cm) is

mostly covered by vesicular black fusion crust; chondrules are

visible on interior surfaces. The thin section shows numerous

chondrules up to 2 mm across and irregular crystalline

aggregates up to 3 mm in maximum dimension, set in a minor

amount of dark brown to black semi-opaque matrix. The

chondrules and aggregates consist mainly of granular olivine

with minor amounts of polysynthetically twinned pyroxene.

Trace amounts of nickel-iron are present as minute grains.

Sulfide is present in small amounts, finely dispersed throughout the matrix and sometimes concentrated in chondrule rims.

Microprobe analyses of chondrule olivines show a wide

composition range: Fa^g, mean Fa n ; the matrix appears to

consist largely of fine-grained iron-rich olivine, Fa40.60.

Pyroxene in the chondrules is clinoenstatite, mostly near Fs15

but with occasional Fe-rich grains. The meteorite is a C3V

chondrite, very similar to ALHA81003; the possibility of

pairing should be considered.

ALH82101 (29.1 g).—The exterior surfaces of this stone (3

x 2.7 x 2.7 cm) are mostly covered with a shiny, blistery fusion

crust. Broken surfaces reveal a gray-beige interior with an

outer, 1 mm thick, discontinuous weathering rind. The matrix

is fine-grained, with metal and a few white to gray inclusions

being visible. The thin section shows an aggregate of small

chondrules (average diameter -0.5 mm), chondrule fragments,

and mineral grains set in an extremely fine-grained, translucent

tan to yellow-brown matrix. The chondrules show a wide

variety of textures; in barred olivine chondrules the material

interstitial to the bars is pale brown isotropic glass. Minor

amounts of nickel-iron and sulfide are present, as small grains

FIGURE 6-3.—C3 chondrite ALH82101.
NUMBER 28 33

FIGURE 6-4.—Photomicrographs of thin sections of C3 chondrites (each field of view is 3 x 2 mm), a,

ALHA81258; b, ALH82101. Note the textural differences between ALHA81258 (C3V) and ALH82101 (C3O).

within some chondrules and also concentrated around their

margins. Numerous small refractory inclusions are present;

identified phases include melilite, deep pink spinel, and

colorless hibonite. Microprobe analyses of olivine show a wide

composition range: Fa^Q, with a mean of Fa22; only a few

grains of pyroxene were found, having a composition range

of FsM 0 . The meteorite is classified as a C3 chondrite of the

Ornans subtype; it is possibly paired with ALHA77003.

Wieler et al. (1985) have reported abundances and isotopic

compositions of He, Ne, and Ar in ALH82101.

CLASS H3

FIGURE 6-5

ALH82110 (39.3 g).—Fusion crust totally covers this small

stone (4.5 x 2.5 x 2.0 cm). Chipping has exposed a weathered

interior with some obvious inclusions. The thin section shows

a close-packed aggregate of chondrules and chondrule

fragments in a minor amount of opaque matrix. Nickel-iron

grains are abundant in the matrix, sometimes concentrated in

chondrule rims; troilite is present in lesser amount. A wide

variety of chondrules is present, ranging up to 2 mm in

diameter; the most common types are porphyritic and granular

olivine and olivine-pyroxene. Microprobe analyses show the

following wide composition ranges in olivine and pyroxene:

olivine, Fa^.^, with a mean of Fa14 (% mean deviation of FeO

is 52; see Dodd et al., 1967, for definition of % mean

deviation); pyroxene, Fs3_2g, with a mean of Fs13 (% mean

deviation of FeO is 48).

PCA82520 (22.7 g).—Dull black fusion crust covers 80%

of the surface of this pyramidal stone (3 x 2 x 1.5 cm), the

remainder being covered with a shiny reddish brown crust.

Extensive weathering has given the matrix a yellowish to

reddish brown color, but some metal is nonetheless preserved.

The thin section shows a close-packed aggregate of chondrules

(up to 1.5 mm in diameter), chondrule fragments, and a few

clasts, with interstitial nickel-iron and troilite and a relatively

small amount of dark matrix. A considerable variety of

chondrules is present, the majority being granular or porphyritic olivine types with transparent to turbid interstitial glass;

other types include fine-grained pyroxene, medium-grained

olivine plus polysynthetically twinned clinopyroxene, and

barred olivine. Brown limonitic staining pervades the section.

FIGURE 6-5.—Photomicrograph of thin section of H3 chondrite ALH82110

(field of view is 3 x 2 mm). A closely packed aggregate of chondrules, irregular

fragments, and mineral grains is set in a minor amount of dark matrix.
34 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Microprobe analyses show olivine mainly in the range Fa15.22,

but one clast has olivine Fa6; the mean composition is Fa17

(% mean deviation of FeO is 27). Pyroxene ranges in

composition from Fs2 to Fs19 with a mean of Fs 14 (% mean

deviation of FeO is 24).

CLASS L3

FIGURES 6-6,6-7

ALHA78013 (4.1 g), 78186 (3.1 g), 78236 (14.4 g), 78238

(9.8 g), 78243 (1.9 g), 81145 (21.1 g), 81156 (19.7 g), 81162

(59.4 g), 81190 (48.3 g), 81191 (30.4 g), 81214 (4.4 g), 81229

(40.0 g), 81243 (15.0 g), 81259 (9.9 g), 81272 (22.9 g), 81280

(54.9 g), 81292 (12.9 g), 81299 (0.5 g).—Examination of thin

sections and microprobe analyses of the minerals in these

meteorites show that they are essentially identical to ALHA77011,

and can confidently be paired with it E.R.D. Scott (personal

communication) has also examined the sections and supports

this interpretation.

ALHA78046 (70.0 g).—Thin section examination shows

that this stone consists almost entirely of a close-packed

aggregate of chondrules and chondrule fragments; most of the

interstitial material consists of nickel-iron and troilite grains,

in places forming rims on the chondrules. Weathering is

extensive, with limonitic staining and small areas of brown

limonite throughout the section. Chondrules range from 0.3 to

3.6 mm in diameter; a variety of types is present, the most

common being granular and porphyritic olivine and olivinepyroxene. Microprobe analyses show considerable variability

in mineral compositions. Olivine compositions range from Fa8

to Fa^, with a mean of Fa19 (% mean deviation of FeO is 20).

Pyroxene compositions range from Fs8 to Fs20, with a mean

of Fs16. The % mean deviation of FeO in olivine is much lower

than that for olivine in the ALHA77011 group, suggesting that

this meteorite is more equilibrated and hence different from

the 77011 group.

ALHA78133 (59.9 g).—Thin section examination shows

that this stone is largely made up of chondrules and chondrule

fragments set in a minor amount of dark matrix. Nickel-iron

and troilite are present in subequal amounts, dispersed through

the matrix as small grains and sometimes forming rims on the

chondrules. A moderate amount of weathering is indicated by

brown limonitic staining throughout the matrix. Chondrules

range in diameter from 0.3 to 1.5 mm; types seen include

porphyritic olivine and olivine-pyroxene, granular olivine and

olivine-pyroxene, devitrified glass, and radiating pyroxene.

Microprobe analyses show olivine ranging in composition from

Fat to FaM with a mean of Fa16 (% mean deviation of FeO is

52); pyroxene ranges in composition from FSj to Fs16 with a

mean of Fs8 (% mean deviation of FeO is 69). In mineral

composition this meteorite is similar to those in the ALHA

77011 group, but E.R.D. Scott (personal communication) states

FlGURE 6-6.—L3 chondrites.

that it appears to lack the graphite-magnetite intergrowths

characteristic of that group.

ALH83010 (395 g).—A black iridescent fusion crust is

present on one side of this meteorite fragment (10.5 x 8 x 2

cm). The other surfaces are dark greenish gray with iridescent

reddish brown areas. Numerous chondrules (1-4 mm in

diameter) and large clasts (the largest is 1.0 x 0.5 cm) are

visible on the exposed interior surfaces. The stone is extremely

coherent. The interior consists of dark matrix with numerous

millimeter-sized, gray to yellowish colored chondrules. Nickeliron is clearly visible. The thin section shows sharply defined

chondrules up to 2.5 mm in diameter, many of which contain

clear brown isotropic glass. Pyroxene is mostly monoclinic and

has a composition range of Fs2_2g. Olivine compositions are in

the range Fa4.31. Metal (two phases present) is subequal with

troilite in abundance. There are well-defined sulfide rims

around many chondrules. Chromite is accessory and is
NUMBER 28 35

FIGURE 6-7.—Photomicrographs of thin section of L3 chondrites (each field of view is 3 x 2 mm): a,

ALHA78046; b, ALHA78133; c, EET82601; d, EET83213. A closely packed aggregate of chondrules, irregular

fragments, and mineral grains set in dark matrix.

generally very fine-grained.

EET82601 (149 g).—This angular to subrounded specimen

is covered with patchy remnants of fusion crust. Chondrules

1-4 mm in diameter are visible on the surfaces where fusion

crust is missing. The interior is very dark with weathered,

millimeter-sized chondrules visible. The thin section shows a

close-packed aggregate of chondrules, ranging up to 1.5 mm

in maximum dimension. A variety of types is present, the

most common being granular olivine and olivine-pyroxene,

porphyritic olivine and olivine-pyroxene, and cryptocrystalline

pyroxene. The small amount of matrix is fine-grained and

opaque, and contains a few grains of nickel-iron and troilite.

The meteorite is considerably weathered, with brown limonitic

staining throughout the section. Olivine and pyroxene show

the following wide ranges of compositions: olivine, Fa2 to

Fa39, with a mean of Fa^ (% mean deviation of FeO is 36);

pyroxene, Fst to Fs35, with a mean of Fs13 (% mean deviation

of FeO is 45).

EET83213 (2727 g).—A dull, fractured fusion crust covers

most of this stone (16 x 15 x 7 cm); evaporite deposits are

present on several surfaces. The interior is greenish gray with

numerous white, cream, and darker gray inclusions or

chondrules. Some metal is present. The thin section shows

sharply defined chondrules up to 3 mm in diameter set in a

brown matrix. Isotropic clear brown glass is preserved in some

chondrules. Moderate limonitic staining is locally present,

indicating mild to moderate weathering. Monoclinic pyroxene

is very common, with a composition range of Fs3.26. Olivine
36 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

ranges in composition from Fa13 to FajQ. Minor metal and

troilite are present in subequal amounts; two metal phases are

present, locally in plessitic intergrowths.

This meteorite is very similar in texture and mineral

compositions to EET82601, and the possibility of pairing

should be considered.

CLASS LL3

FIGURE 6-8

TIL82408 (80.1 g).—A polygonally fractured, black fusion

crust coats much of this stone (4.5 x 4 x 2.5 cm). Areas without

fusion crust are somewhat friable. The meteorite is clast-rich,

with a very dark gray to black matrix. Oxidation is evenly

distributed throughout the interior. The thin section shows a

close-packed aggregate of chondrules and chondrule fragments, up to 4 mm across. The matrix is black and opaque,

much of it forming rims to the chondrules; the matrix contains

much sulfide and a little nickel-iron (largely weathered to

limonite). A wide variety of chondrule types is present,

including porphyritic olivine and olivine-pyroxene, granular

olivine and olivine-pyroxene, barred olivine, and fine-grained

pyroxene. Some of the chondrules preserve clear, isotropic,

interstitial glass. Microprobe analyses show the following wide

ranges of compositions for olivine and pyroxene: olivine,

Faj_29, with a mean of Fa15 (% mean deviation of FeO is 41);

pyroxene, Fs2_21, with a mean of Fs9. The highly variable

compositions of olivine and pyroxene and the presence of

isotropic glass indicate type 3, and the small amount of

nickel-iron suggests the LL group; the meteorite is thus

tentatively classified as an LL3 chondrite.

Wieler et al. (1985) have reported abundances and isotopic

compositions of He, Ne, and Ar in TIL82408.

CLASS C4

FIGURES 6-9, 6-10

ALH82135 (12.1 g).—Black fusion crust covers most of

this triangular-shaped stone (3 x 2.5 x 1 cm). Freshly broken

surfaces expose a dark bluish gray matrix with signs of some

oxidation. In thin section the meteorite consists largely of

finely granular olivine (grains ranging up to 0.1 mm), minor

pyroxene, plagioclase, and opaques. A few relatively coarsegrained olivine chondrules are present. Microprobe analyses

give the following compositions: olivine, Fa27 (a few grains

are more iron-rich); pyroxene, Fs25; plagioclase, An20_75. This

meteorite is similiar to Karoonda and PC A82500 in texture and

mineral compositions.

Wieler et al. (1985) have reported abundances and isotopic

compositions of He, Ne, and Ar in ALH82135. Scott (1985)

has discussed its petrology.

PCA82500 (90.9 g).—This specimen (7 x 5 x 2.8 cm) has

a very unusual external appearance. It is extremely fragmented

and has numerous rounded cavities, some of which extend

through the thickness of the specimen to give it a "swiss

cheese" appearance. The cavities were filled with ice and snow

when the meteorite was found. Several patches of fusion crust

are present. The exterior surfaces vary in color from dark gray

to lighter gray and yellowish gray, the lighter colors being

characteristic of the less weathered areas. Inclusions (chondrules?) are exposed on those portions of the exterior surface

that lack fusion crust. White evaporite deposits and yellowcolored weathering residues are abundant on interior surfaces;

the white material is an unusual nickel-rich magnesium sulfate

(J. Gooding, personal communication, 1986). In spite of the

weathering and evaporite deposits, the interior surfaces reveal

a fine-grained matrix with minute metal flecks and a few

FIGURE 6-8.—Photomicrograph of thin section of LL3 chondrite TIL82408

(field of view is 3 x 2 mm). Chondrules, chondrule fragments, irregular

fragments, and mineral grains are set in a dark matrix. FIGURE 6-9.—C4 chondrite PCA82500.
NUMBER 28 37

FIGURE 6-10.—Photomicrographs of thin section of C4 chondrites (each field of view is 3 x 2 mm): a,

ALH82135; b, PCA82500. In ALH82135, sparse chondrules are set in a matrix consisting largely of fine-grained

olivine. In PCA82500, the lower left area shows a segment of a large (3.6 mm diameter) chondrule.

yellowish dots of oxidation. The thin section contains a single

porphyritic olivine chondrule, diameter 3.6 mm, in an

aggregate of turbid anhedral olivine grains averaging 0.1 mm.

Small amounts of troilite and nickel-iron are present, the metal

being largely weathered to brown limonite. Microprobe

analyses show a uniform olivine composition of Fa31, and

variable plagioclase in the range An^ to An^. No pyroxene

was found. This meteorite was classified in the Antarctic

Meteorite Newsletter, 6(2), as an LL6 chondrite, but has since

been recognized as a C4 chondrite that is very similar to

Karoonda (Scott, 1985).

Wieler efal. (1985) have reported abundances and isotopic

compositions of He, Ne, and Ar in PCA 82500. Scott (1985)

concludes that Karoonda, PCA 82500, Yamato 6903, and

Mulga (West) are very similar and may have come from the

same body.

CLASS E4

FIGURE 6-11

ALHA81189 (2.6 g).—No fusion crust remains on this

fractured reddish brown stone (2 x 1.5 x 0.5 cm). The thin

section shows an aggregate of chondrules, chondrule fragments, and mineral grains set in an opaque matrix. The

chondrules range up to 0.9 mm in diameter; most of them

consist of granular pyroxene (sometimes with a little olivine),

but a few are made up of nickel-iron and troilite. The matrix

consists largely of nickel-iron and troilite, with a considerable

amount of secondary limonite. Microprobe analyses show that

the pyroxene is close to MgSiO3 in composition (FeO

0.5%-4.5%, with a mean of 1.9%; A12O3 0.02%-2.4%, mean

0.7%; CaO 0.1%-0.7%, mean 0.3%; TiO2 0%-0.13%, mean

0.08%; MnO 0.07%-0.22%, mean 0.15%). Most of the olivine

grains are close to Mg2Si04 in composition (FeO 0.7%-6.4%).

One grain of a silica polymorph was analyzed. The metal

contains approximately 2.5% Si. Because some of the pyroxene

is polysynthetically twinned clinoenstatite, the meteorite is

tentatively classified as an E4 chondrite.

ALH82132 (5.9 g).—No fusion crust remains on this

iridescent, reddish brown, highly oxidized stone (2x2x 1

cm). A thin coating of evaporite deposits are present on some

of the extensively weathered interior surfaces. Thin section

examination shows that chondrules are relatively abundant but

small, ranging up to 0.6 mm in diameter. Most of them consist

of pyroxene, but some are made up almost entirely of

nickel-iron and troilite. The matrix consists largely of granular

pyroxene, with lesser amounts of nickel-iron and sulfides, a

little plagioclase and a silica polymorph. The meteorite is

considerably weathered, with brown limonitic staining throughout the section. Microprobe analyses show that the pyroxene

is almost pure MgSiO3 (FeO 0.06%-0.7%, mean 0.3%; A12O3

0-0.3%, mean 0.04%; CaO 0.02%-0.6%, mean 0.16%; TiO2

and MnO each less than 0.05%). Plagioclase is almost pure

albite (CaO 0.2%, K2O 0.11%). The meteorite is an enstatite

chondrite and, since some of the pyroxene is polysynthetically

twinned clinoenstatite, it is classified as an E4 chondrite.

E.R.D. Scott (personal communication) has examined the

thin sections of the E4 chondrites from the Allan Hills, and

comments that 81189 and 82132 are definitely not paired,

82132 appearing more equilibrated than 81189; 81189 does

resemble 77156 and 77295, and may tentatively be paired with

them.

PCA82518 (21.9 g).—The fusion crust coating this stone

(3 x 2.5 x 2 cm) is shiny, iridescent, and ranges in color from

orange-red to brown to black. The exterior is dotted with

numerous vugs that are lined with fusion crust. Exposed

interior surfaces reveal a dark brown matrix with abundant

chondrules (as large as 3 mm in diameter) and metal. Thin
38 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-11.—Photomicrographs of thin sections of E4 chondrites (each field

of view is 3 x 2 mm): a, ALHA81189; b, ALH82132; c, PCA82518. All three

sections show chondrules, chondrule fragments, and mineral grains (mainly

clinoenstatite) in an opaque matrix consisting largely of nichel-iron and troilite.

section examination shows that the chondrules are abundant

but generally small, ranging from 0.3 to 0.9 mm in diameter;

they consist of granular or fine-grained pyroxene. The matrix

consists largely of granular pyroxene, with lesser amounts of

nickel-iron and sulfides, and a little plagioclase. The meteorite

is considerably weathered, with brown limonitic staining

throughout the section. Microprobe analyses show that the

pyroxene is almost pure MgSiO3 (FeO 0.2%-0.8%, mean

0.5%; A12O3 0.07%-0.7%, mean 0.5%; CaO 0.04%-0.7%,

mean 0.2%; TiO2 and MnO each less than 0.1%). Plagioclase

is almost pure albite (K2O 0.6%, CaO less than 0.1%). One

grain of forsteritic olivine was analyzed. The meteorite is an

enstatite chondrite and, since part of the pyroxene is

polysynthetically twinned clinoenstatite, it is classified as E4.

CLASS H4

FIGURES 6-12,6-13

ALHA78051 (119 g).—In thin section this stone is seen to

consist of numerous chondrules, up to 1.5 mm in diameter, set

in finely granular matrix of olivine, pyroxene, nickel-iron, and

troilite. Moderate weathering is indicated by brown limonitic

staining concentrated around metal grains. Well-preserved

fusion crust borders one edge of the section. Microprobe

analyses show olivine to be uniformly Fa18 in composition; the

pyroxene composition is somewhat variable, Fs15.lg.

ALH82126 (139 g).—This stone (7 x 4 x 2.5 cm) was

completely covered with dull brown fusion crust. Chipping

revealed some inclusions in the heavily weathered interior. The

thin section shows numerous chondrules, up to 2 mm in

diameter, in a granular groundmass of olivine and pyroxene,

with minor nickel-iron and lesser amounts of troilite. Brown

limonitic staining pervades the section. Remnants of fusion

crust are present on one edge. Microprobe analyses give the

following compositions: olivine, Fa18; pyroxene is somewhat

variable, Fs14.18.

EET82602 (1824 g).— An extremely thin, black fusion crust

completely covers the regmaglypted surface of this meteorite
NUMBER 28 39

(10 x 14 x 8 cm). The stone broke along a pre-existing fracture,

exposing both weathered and unweathered material. The

material exposed is orange-brown with abundant visible metal

(this may not be representative of the entire specimen).

Chondritic structure is well developed in thin section, with

chondrules ranging up to 1.5 mm in diameter. A variety of

chondrule types is present, including porphyritic and barred

olivine (with turbid, devitrified glass between the olivine

crystals), granular olivine, olivine-pyroxene, and fine-grained

pyroxene. Some of the pyroxene is polysynthetically twinned

clinobronzite. The chondrules are set in a fine-grained granular

groundmass of olivine and pyroxene, with minor amounts of

nickel-iron and troilite. Brown limonitic staining pervades the

section, and veinlets of red-brown limonite are present.

Microprobe analyses give the following compositions: olivine,

Fa19; pyroxene, Fs16.

EET82609 (325 g).—This stone (7.5 x 5 x 3.5 cm) is angular

with rounded corners. Brownish black fusion crust or remnant

fusion crust covers the entire specimen. The interior has a dark

matrix with reddish brown oxidation disseminated throughout.

The thin section shows a close-packed aggregate of small

chondrules, ranging up to 0.6 mm in diameter, set in a granular

groundmass consisting largely of olivine and pyroxene, with

minor amounts of nickel-iron and troilite. Some of the

pyroxene is polysynthetically twinned clinobronzite. Brown

limonitic staining pervades the section. Microprobe analyses

give the following compositions: olivine, Fa18; pyroxene Fs17

(the pyroxene is somewhat variable in composition).

EET83207 (1238 g).—A black to reddish brown fusion crust

covers this oblong meteorite (15 x 7.5 x 6 cm ). Several deep

fractures penetrate the interior, one splitting the stone almost

in half. The interior is mostly dark reddish brown, although

small areas of less-weathered yellowish matrix are still present.

The thin section shows well-defined chondrules up to 2 mm

in diameter. Microcrystalline structure is preserved in some

chondrules , but glass is devitrified. Olivine is uniformly Fa18

in composition. Monoclinic pyroxene (Fs16_18) is common.

Two metal phases are present, and tetrataenite (Ni 55%) is also

present locally. Troilite is subordinate to metal in abundance.

Chromite is accessory. This meteorite was originally classified

as H4-5 in the Antarctic Meteorite Newsletter, 8(1).

EET83211 (542 g).—A weathered, polygonally fractured

fusion crust covers 75% of this meteorite fragment (10 x 7 3.5

cm). The surface is iridescent in places, and a minor amount

of evaporite deposit is present. The interior of the stone is also

very fractured; broken surfaces are reddish brown and quite

smooth. The interior is extremely weathered, but some metal

is nonetheless visible. The thin section shows sharply defined

chondrules up to approximately 0.6 mm in diameter in a

microcrystalline groundmass. Metal is abundant and exceeds

troilite in amount. Intense limonitic staining, together with

hematite veins, indicate heavy weathering. The olivine

composition is relatively uniform, Fa18.20. Pyroxene is

commonly monoclinic, with a narrow composition range of

FIGURE 6-12.—H4 chondrites.

Fs1620. Some very fine-grained plagioclase (An12Or5) was

found.

PCA82511 (149 g).—Flow marks are apparent in the

iridescent brown to black fusion crust on the top surface (as

oriented on the ice) of this stone (5.5 x 6 x 3.5 cm). The bottom

surface shows several fractures and the fusion crust is

extensively weathered, having an orange tinge. The interior

that was exposed by chipping may not be representative of the

entire stone; it is heavily weathered with only small areas of

unweathered light gray material. In thin section, chondrules are

abundant and well-developed. A variety of types is present, the

commonest being porphyritic olivine, porphyritic olivinepyroxene, and radiating pyroxene. Much of the pyroxene is

polysynthetically-twinned clinobronzite. The matrix consists

of fine-grained olivine and pyroxene, with minor amounts of

nickel-iron and troilite; it is heavily stained with limonite.

Well-preserved fusion crust is present along one edge of the

section. Microprobe analyses give the following compositions:
40 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-13.—Photomicrographs of thin sections of H4 chondrites (each field of view is 3 x 2 mm): a,

PCA82524; b, PCA82511. Although both contain numerous well-defined chondrules, some chondrule margins

tend to merge with the granular matrix.

olivine, Fa17; pyroxene, Fs15.

PCA82524 (113 g).—A black fusion crust covers most of

this cuboidal stone (5 x 4 x 3.5 mm). Chipping exposed a

continuous weathering rind, light gray matrix and numerous

small light and dark inclusions. In thin section chondrules are

abundant and well-developed, ranging up to 1.2 mm in

diameter; a variety of types is present, including barred olivine,

granular and porphyritic olivine-pyroxene, and fine-grained

pyroxene. Some of the pyroxene is polysynthetically twinned

clinobronzite. The groundmass consists largely of fine-grained

olivine and pyroxene, with minor amounts of nickel-iron and

troilite. A minor degree of weathering is indicated by brown

limonitic staining around metal grains. Microprobe analyses

give the following compositions: olivine, Falg; pyroxene, Fs16.

CLASS L4

FIGURES 6-14,6-15

ALH83001 (1568 g).—Shallow regmaglypts are present on

this fusion-crusted stone (17.5 x 9 x 6.5 cm). Most of the

interior that has been exposed by chipping is weathered, but it

may not be representative of the entire stone. The less

weathered material is medium gray and contains chondrules.

The thin section shows sharply defined chondrules up to 2.5

mm in diameter, in which original brown glass is now turbid

and birefringent. Metal (mostly one-phase) and troilite are

subequal in amount. Light to moderate limonitic staining

indicates mild weathering. Olivine composition is somewhat

variable, Fa23.28. Monoclinic pyroxene is abundant, and has a

composition range of Fs20_32.

PCA82514 (129 g).—A dull black fusion crust is present

on one surface of this stone (6 x 3 x 3 cm), the other surfaces

having weathered to reddish brown. The interior is medium

gray and shows dark and light inclusions. A partial weathering

rind was exposed when the stone was chipped. In thin section

chondrules are abundant and well-developed, ranging up to 2

mm in diameter; a variety of types is present, including

porphyritic olivine, porphyritic olivine-pyroxene, barred olivine, and fine-grained olivine and pyroxene. Much of the

pyroxene is polysynthetically-twinned clinobronzite. The

matrix consists of fine-grained olivine and pyroxene, with

coarser grains of nickel-iron and troilite. Brown limonitic

staining surrounds the metal grains. Microprobe analyses give

the following compositions: olivine, Fa23; pyroxene somewhat

variable, Fs^^ , mean Fs18.

The following four specimens are L4 chondrites from the

Thiel Mountains that are possibly paired. All are very similar

in their textures, mineral compositions, and degree of

weathering. The thin sections all show a close-packed

aggregate of chondrules, up to 3 mm in diameter, in a minor

amount of granular groundmass that consists of olivine,

pyroxene and minor amounts of nickel-iron and troilite. Brown

limonitic staining pervades the sections. Microprobe analyses

give the following compositions: olivine Fa^.^; pyroxene is

somewhat variable, with a mean of Fs20_21.

TIL82404 (321 g).—This stone (7 x 7.5 x 3 cm) is partly

covered with brownish black fusion crust; many inclusions are

visible in areas devoid of crust. Chipping has exposed a dark

gray matrix that is inclusion- and metal-rich, with evenly

distributed oxidation.

TIL82406 (152 g).—This stone (5.5 x 5.0 x 3.5 cm) is

angular with subrounded edges, and most of it is covered with

dull black fusion crust. The dark gray interior shows numerous

inclusions, and oxidation is evenly scattered throughout.
NUMBER 28 41

TIL82407 (220 g).—This is an angular oblong stone (9.5 x

4.5 x 3 cm) with three flat sides, completely covered with

brownish black fusion crust. Abundant oxidation haloes are

obvious on the surface. Most of the interior has weathered to

a deep reddish brown, but fresh material is dark gray.

TIL82411 (179 g).—This meteorite (6.5 x 4.5 x 3 cm) is

covered with slightly weathered fusion crust. No fractures are

present. The interior is dark and slightly weathered, and

contains abundant chondrules 1-2 mm in diameter.

FIGURE 6-14.—L4 chondrites.

TYR82700 (892 g).—Black to brown fusion crust covers

60% of this stone (10 x 8.5 x 7 cm). Other surfaces are brown

with light inclusions. A white evaporite deposit dots the

surface. The interior is extensively oxidized. The thin section

shows a close-packed aggregate of chondrules and chondrule

fragments, set in a minor amount of granular matrix. A variety

of chondrule types is present, including granular olivine,

porphyritic olivine, porphyritic olivine-pyroxene, barred olivine, and radiating fibrous pyroxene. Much of the pyroxene is

polysynthetically twinned clinobronzite. Minor amounts of

nickel-iron and troilite are present, interstitial to the chondrules.

Minor weathering is indicated by brown limonitic staining

around metal grains. Microprobe analyses give the following

compositions: olivine, Fa^; pyroxene somewhat variable,

Fs15_23, mean Fs18.

CLASS H5

FIGURES 6-16,6-17

ALHA81161 (122 g).—This stone (6.5 x 4 x 2.8 cm) has

thin fusion crust on one side. It is extremely fractured and

brown to iridescent brown. Chipping exposed a totally

weathered interior.

ALHA81183 (104 g).—Dull fusion crust covers most of this

stone (6 x 3.5 x 3 cm); areas without fusion crust have an

iridescent red-brown color. Several fractures penetrate the

interior, which has a deep reddish brown color.

ALHA81295 (105 g).—Some very thin fusion crust is

preserved on one surface of this meteorite (7 x 4.5 x 2 cm).

The surface color is iridescent reddish brown. Many fractures

penetrate the interior, which is extensively weathered.

ALH82102 (48 g).—This stone was found weathering out

of the ice in the Far Western Icefield. It was collected in situ

inside of a large block of encasing ice (see Frontispiece). The

ice block was sent to an ice coring lab in New Hampshire and

determined to be original (not refrozen) ice; see Chapter 10.

The dull black, polygonally fractured fusion crust of the

meteorite contains many centimeter-size oxidation haloes that

are orange-red. One fracture surface is reddish brown. The

interior of the meteorite is uniformly very weathered.

ALH82103 (2529 g).—A slightly weathered fusion crust

covers nearly all of this meteorite (14 x 11 x 9 cm).

Regmaglypts occur on several faces. Surfaces without fusion
42 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-15.—Photomicrographs of thin sections of L4 chondrites (each field of view is 3 x 2 mm): a, TIL82406;

b, PCA82514. Chondritic structure is prominent, but some chondrules show partial integration with the granular

matrix.

crust show a 1-2 mm thick weathering rind, but a few small

clasts are visible. The interior consists of gray matrix dotted

with oxidation.

ALH82122 (142 g).—A thin fusion crust covers this

rectangular meteorite (4.5 x 4 x 2.5 cm). The interior is light

to dark gray with oxidation haloes around metal grains.

EET82603 (8210 g).—This large stone (18 x 19 x 14 cm)

is almost completely covered with a black, polygonally

fractured fusion crust. White evaporite deposits occur on four

of the six sides of the meteorite and are quite thick in some

places. As in the cases of other Antarctic meteorites having

evaporite deposits (see description for ALH83100), the

deposits on EET82603 formed while the sample was drying

in the gaseous nitrogen atmosphere of the storage cabinets in

Houston. Chipping of the meteorite revealed that a weathering

rind is also present. The interior matrix is gray with large areas

having a dark gray to deep reddish brown color. Extensive

weathering has occurred along internal cracks.

EET82604 (1570 g).—A thin black fusion crust coats most

of this blocky meteorite (11 x 11x8.5 c m). The stone broke

along a pre-existing fracture, exposing mostly weathered

material, though metal is still obvious, as is a small amount

of less-weathered material.

EET83200 (778 g).—This angular chondrite (10 x 8 x 5

cm) is covered with weathered black fusion crust that is pitted

with oxidation. Row lines are present on part of one surface.

The stone is broken, and the exposed surface is weathered to

a shiny dark brown. The interior is a dark reddish brown with

a small band of relatively unweathered material. This meteorite

was originally classified H4-5 in the Antarctic Meteorite

Newsletter, 8(1).

EET83203 (545 g).—No fusion crust remains on this smooth

reddish brown chondrite (6.5 x 7.5 x 6 cm). Several deep

parallel fractures penetrate the interior, which is reddish brown

with some areas less weathered than others. Metal flecks are

visible.

EET83208 (263 g).—This meteorite (11 x 5.5 x 3 cm) is

totally covered by a smooth black fusion crust. Several

penetrating fractures and a number of regmaglypts are present.

The stone broke in half along a fracture, and the interior is

extensively weathered. Further chipping has revealed a

less-weathered dark interior.

TIL82409 (230 g).—A black to slightly weathered fusion

crust covers nearly all the meteorite (6.5 x 4.5 x 4.5 cm). The

interior has a yellowish tinge and large dark haloes from

weathering.

In thin section, all of the H5 chondrites show a generally

well-developed chondritic structure with a variety of chondrule

types, including granular olivine, porphyritic olivine, porphyritic olivine-pyroxene, barred olivine, and fine-grained pyroxene.

Chondrule margins may be somewhat diffuse, tending to merge

with the granular groundmass. The latter consists largely of

olivine and pyroxene, with minor amounts of 2-phase

nickel-iron, troilite, and chromite; minute grains of sodic

plagioclase can sometimes be detected. The compositions of

the olivine (Fa1649) and pyroxene (Fs14.17) are uniform within

the individual specimens.

CLASS L5

FIGURES 6-18,6-19

ALH82104 (398 g).—This stone (6 x 6 x 6 cm) is mostly

covered with a thin black fusion crust. The exposed underlying
FIGURE 6-16.—H5 chondrites. Note the flow lines on the fusion crust of EET83200.

FIGURE 6-17.—Photomicrographs of thin sections of H5 chondrites (each field of view is 3 x 2 mm): a, EET82603; b,

TTL82409. Chondritic structure is well-developed, but chondrule margins tend to merge with the granular groundmass.
44 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

surfaces are brown and rough in texture. The interior is made

up of light gray matrix with rounded and irregular inclusions.

A few oxidation haloes and a continuous weathering rind are

present.

PCA82504 (3093 g).—Fusion crust covers 80% of the

surface of this meteorite (18x 12x9cm), and is dotted with

oxidation. Areas not covered with fusion crust are somewhat

weathered but still reveal a grayish matrix. The interior is gray,

contains small inclusions, and is dotted with oxidation haloes.

PCA82505 (3085 g).—Patches of fusion crust remain on

this meteorite (16 x 11 x 11 cm). Exposed underlying surfaces

are generally reddish brown, with lighter colored inclusions

evident. A major fracture divides the stone in half. The interior

is dark with reddish oxidation.

PCA82510 (254 g).—Some of the blackish brown fusion

crust has been plucked off, exposing the clast-rich interior of

this stone (6.5 x 4.5 x 4 cm). The matrix is medium gray and

loaded with inclusions, both rounded and irregular. The stone

is amazingly fresh; minor pockets of oxidation are present, but

they are the exception.

PCA82513 (239 g).—One face of this stone (6 x 5 x 4 cm)

is rounded and smooth, with a shiny black to weathered fusion

crust. The other faces have a dull fractured fusion crust that is

slightly blistery in places. Flow lines are present. The interior

is light gray with occasional dark gray inclusions or

chondrules. Metal flecks are visible, and are commonly

surrounded by oxidation haloes. A discontinuous weathering

rind is present.

PCA82519 (125 g).—A dull brownish black fusion crust

covers 80% of this meteorite fragment (4x6x 3 cm).

Oxidation is evenly disseminated throughout the interior.

Unweathered matrix is dark gray and inclusion-rich.

TIL82400 (220 g).—This meteorite (8 x 5 x 5 cm) has only

a few remnant patches of fusion crust. The exposed underlying

meteorite is friable, has a rough texture and reddish brown

color, and shows numerous gray-green chondrules (1-3 mm

1 cm

FIGURE 6-18.—L5 chondrites.
NUMBER 28 45

FIGURE 6-19.—Photomicrographs of thin section of L5 chondrites (each field of view is 3 x 2 mm): a,

PCA82505; b, TIL82400. Chondrules are prominent, but show some integration with the granular groundmass.

diameter). The interior is light gray with some oxidation.

In thin section the L5 chondrites show a generally

well-developed chondritic structure, with a variety of chondrule types, including porphyritic olivine, granular olivine,

granular olivine-pyroxene, and radiating pyroxene. Chondrule

margins are commonly diffuse, tending to merge with the

granular groundmass. The latter consists largely of olivine and

pyroxene with minor subequal amounts of nickel-iron and

troilite. The compositions of the olivine (Fa23,25) and

largely-orthorhombic pyroxene (Fs1921) are essentially uniform within individual specimens.

CLASS E6

FIGURE 6-20

ALHA81260 (124.1 g).—A weathered fusion crust covers

about 80% of this stone (4.5 x 5 x 3 cm). The one fracture

surface has weathered to a deep reddish brown. A minute

amount of evaporite deposit is present and is most abundant

immediately underneath the fusion crust. The stone is

extremely hard to break. The interior matrix is bluish black,

with black and white crystal faces being obvious under a

binocular microscope. Only vague traces of chondritic structure

are visible in the thin section, which shows the meteorite to

consist largely of granular enstatite, a considerable amount of

nickel-iron (-20%) and minor amounts of sulfides and

plagioclase. Remnants of fusion crust are present in the section.

Weathering is minor, with a little limonitic staining around

some metal grains. Microprobe analyses show the enstatite is

almost pure MgSiO3 (CaO 0.8%; FeO 0.2%; A12O3, TiO2, and

MnO each <0.1%); plagioclase is somewhat variable in

composition, An13 19. The meteorite is an E6 chondrite; the

only other E6 chondrite from the Allan Hills, ALHA 81021,

FIGURE 6-20.—Micrograph of thin section of the E6 chondrite ALHA81260

(Field of view is 3 x 2 mm). Chondritic structure is barely perceptible, the

section showing a granular aggregate consisting largely of enstatite (white to

gray) and nickel-iron and troilite (black).

is similar but appears to be more weathered. The possibility

of pairing should be considered.

CLASS H6

FIGURES 6-21,6-22

EET83201 (1059 g).—No fusion crust remains on this

polished and rounded stone (10 x 8 x 7 cm). It was chipped

along a crack, exposing a reddish brown interior with metal

flecks. Thin section examination shows well-preserved chondrules up to 2 mm in diameter, enclosed in a matrix that is

intensely recrystallized to a coarse polygonal-granular texture.
46 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

1 cm

FIGURE 6-21.—H6 chondrites. Note the oxidation haloes on the surface of

TIL82405.

Plagioclase (An1314Ab80.glOr6) is well-developed and abundant. Orthorhombic pyroxene (Fs 18) and olivine (Fa18.20) are

uniform in composition. Metal and troilite are subequal in

abundance. Chromite is an accessory phase.

EET83215 (510 g).—This meteorite (9 x 7 x 6 cm) consists

of three pieces (one large and two small) that fit together

perfectly. The exterior is shiny, smooth, and reddish brown

with some remnants of fusion crust. Fracturing is extensive.

The interior surfaces are heavily weathered; some metal was

noted. In thin section, chondrules up to 2 mm in diameter are

fairly well-preserved; some retain microcrystalline structure.

Plagioclase is abundant and coarse but is highly maskelynetized. Olivine and mostly-orthorhombic pyroxene are very

uniform in composition, Fa18 and Fs19 respectively. Metal is

more abundant than troilite; at least two metal phases are

present, including some tetrataenite (approximately 52% Ni).

This meteorite was originally classified as H5-6 in the

Antarctic Meteorite Newsletter, 8(1).

TIL82405 (1001 g).—Three perfectly fitting pieces make

up this specimen (15 x 10 x 14 cm). The fusion crust is

polygonally fractured and shows oxidation haloes. The interior

is gray with small specks of oxidation. A 1-4 mm thick

weathering rind is present. In thin section chondrules are sparse

and poorly defined, tending to merge with the granular

groundmass. The latter consists largely of olivine and

pyroxene, with minor amounts of nickel-iron, plagioclase, and

troilite. Brown limonitic staining surrounds the metal grains.

Microprobe analyses give the following compositions: olivine,

Fa19; pyroxene, Fs17; plagioclase, An13.

FIGURE 6-22 (Below).—Photomicrographs of thin sections of H6 chondrites

(each field of view is 3 x 2 mm), a, TIL82405; b, EET83201. Chondrules are

present, but tend to merge with the granular groundmass.
NUMBER 28 47

CLASS L6

FIGURES 6-23,6-24

ALH81247 (104 g).—This stone (5.5 x 4 x 3 cm) is covered

with a dull, blistery fusion crust. Numerous fractures

criss-cross the surface but do not extend far into the interior.

A minute amount of evaporite deposit is present. The interior

is light gray with numerous inclusions, some more than 1 mm

in largest dimension. A weathering rind 1-9 mm thick is

present.

ALH82105 (363 g).—This stone (8 x 7.5 x 3 cm) is flat

with well-rounded edges and is totally covered with a brown

to black, polygonally fractured fusion crust showing many

oxidation haloes. A continuous weathering rind, 1-5 mm thick,

was exposed on chipping. The interior is whitish gray with a

few areas of oxidation. Abundant metal is obvious.

ALH82118 (110 g).—Remnants of black fusion crust are

present on this meteorite (5 x 4.5 x 3 cm). Elsewhere the

surface is rough and friable, with a light gray matrix dotted

with oxidation haloes around metal grains. One deep fracture

penetrates the stone.

ALH82123 (110 g).—Fusion crust covers most of this stone

(6 x 4 x 3 cm). Chondrules up to 5 mm in diameter are visible

on a fracture surface. A 5 mm thick weathering rind was

exposed when the meteorite was chipped.

ALH82125 (178 g).—A dull to lustrous fusion crust covers

this dumbbell-shaped meteorite (8 x 3.5 x 2.5 cm). The interior

is highly weathered.

ALH83101 (639 g).—This smooth rounded stone (9 x 8 x

5.5 cm) is covered with a black, polygonally fractured fusion

crust. One surface is flat and iridescent. Areas where fusion

crust has weathered away reveal a rough reddish surface with

areas of gray matrix. The interior is light gray and sparsely

dotted with oxidation. Metal flecks are numerous.

1 cm

FIGURE 6-23.—L6 chondrites.
48 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-24.—Micrographs of thin sections of L6 chondrites (each field of view is 3 x 2 mm): a, EET83214;

b, EET83206. Chondritic structure is barely discernible in these samples, the chondrules merging with granular

groundmass. Note the dark glassy shock veining in EET83206.

EET82605 (624 g).—This angular stone (9 x 7.5 x 5.5 cm)

is mostly covered with a black fusion crust. Chipping has

revealed a discontinuous weathering rind 1.7-2 mm thick. The

fresher interior is light in color with oxidation scattered

throughout. Several inclusions were noted.

EET82606 (981 g).—This angular meteorite (11.5 x 9 x 7

cm) is smooth and dark reddish brown with remnants of fusion

crust. Several fractures penetrate the stone. Light grayish

yellow matrix with numerous inclusions and oxidation haloes

make up the interior.

EET82607 (165 g).—This stone (5.5 x 4 x 4 cm) appears

to be one-half of what was formerly a thin oblong-shaped

specimen. Fusion crust is present on all but one face; this face

has a rough texture and a reddish brown color, with

lighter-colored inclusions or chondrules and some tiny metal

grains being visible.

EET83202 (1213 g).—This meteorite (12 x 7 x 7.5 cm) is

roughly rectangular, with about 50% of its surface covered

with fusion crust. Where the fusion crust has weathered away,

the surface is smooth and reddish brown. Fractures are

numerous. The interior is light and dark gray with abundant

millimeter-sized light inclusions. This meteorite was originally

classified as L5-6 in the Antarctic Meteorite Newsletter, 8(1).

EET83205 (470 g).—This chondrite (8x7x 4 cm) has

patches of shiny fusion crust scattered over its otherwise

reddish brown surface. Several fractures penetrate the interior,

which is white to yellow-gray. A gray to reddish brown

weathering rind is present.

EET83206 (461 g).—This rectangular stone (10 x 5 x 4.5

cm) is covered with a black to reddish brown fusion crust. The

interior is grayish with a discontinuous weathering rind and

some large oxidation haloes. Glassy veins crisscross the

interior.

EET83209 (520 g).—This stone (8 x 7 x 6 cm) is rounded

and smooth with scattered remnants of fusion crust; surfaces

that lack fusion crust are reddish brown and slightly polished.

The interior is reddish to yellowish, heavily weathered but with

some visible metal flecks. Plagioclase is locally maskelynitized.

EET83210 (425 g).—Patches of fusion crust remain on

approximately 30% of this meteorite fragment (9.5 x 6 x 6

cm); the other surfaces are smooth and reddish brown. The

interior is gray with some oxidation staining; metal flecks are

present. A discontinuous weathering rind is present.

EET83214 (1397 g).—This stone is 75% covered with

fractured and weathered black fusion crust; the rest of the

surface is reddish brown, has a rough texture, and shows some

yellowish matrix. A 5 mm thick reddish brown weathering rind

was exposed by chipping. The interior is gray with some

oxidation; metal is abundant.

EET83237 (882 g).—A few small patches of fusion crust

remain on this rounded reddish brown stone (10 x 7 x 5.5

cm). A small area was chipped off, exposing a fracture

(possibly annealed) that is preferentially weathered and a

yellowish matrix. Metal flecks and a few inclusions are visible.

PCA82503 (8308 g ).—This large stone (27 x 17 x 12 cm)

consists of two pieces that fit together perfectly, each covered

with a thin black fusion crust except for the fracture surface.

The bottom (as oriented on the ice) is smooth and has some

deep regmaglypts. The fracture surface has weathered to a

yellowish brown color and has a rough texture. The interior is

light gray with some oxidation haloes. A discontinuous

weathering rind, 1-2 mm thick, is present.

PCA82508 (389 g).—This is a well-rounded oblong

meteorite (9 x 5 x 4 cm) with a black fusion crust coating all

but one corner. This exposed area is somewhat weathered to a
NUMBER 28 49

reddish brown color. The interior is light gray with light and

dark inclusions (chondrules?), and shows some oxidation

haloes.

PCA82509 (285 g).—A brownish black fusion crust

completely covers this cuboidal meteorite (5x5x 4 cm).

Chipping has exposed an area that is mostly oxidized but

probably not representative of the entire specimen. Fresh

material is light gray with abundant fresh metal visible.

TIL82401 (281 g).—A thin, dull black fusion crust coats

parts of three surfaces of this fragment (6.5 x 6 x 5.5 cm). The

other surfaces are smooth and reddish brown. Chondrules (1-6

mm diameter) are visible. A wide discontinuous weathering

rind was exposed on chipping, as was fresh gray matrix with

a minor amount of oxidation.

The L6 chondrites are all very similiar in their petrographic

characteristics. The thin sections show sparse, poorly defined

chondrules that tend to merge with the granular groundmass.

Principal minerals are olivine and pyroxene in subequal

amounts, together with minor quantities of plagioclase (or

maskelynite), nickel-iron, troilite, diopside, and accessory

chromite and merrillite. Microprobe analyses (see Appendix,

Table A) show essentially uniform compositions for the

principal minerals: olivine, Fa^.^; orthopyroxene, Fs19.21;

plagioclase, An1(M2. The following meteorites contain maskelynite: EET82605, EET82606, PCA82503, PCA82509,

EET83209.

CLASS LL6

FIGURES 6-25,6-26

EET83204 (376 g).—A polygonally fractured fusion crust

has spalled off large areas of this stone (8x6x 5 cm). Areas

devoid of fusion crust have a rough texture. The interior is

gray without visible weathering, except for a discontinuous

darker gray rind and several reddish haloes. Metal flecks are

present. A thin section shows poorly defined chondrules up to

2 mm in diameter. The matrix is intensely recrystallized to a

well-developed polygonal granular texture. Metal (two-phase,

mostly as coarse patchy intergrowths) and troilite are both very

low in abundance. Minor local limonitic staining suggests mild

weathering. Olivine and orthopyroxene are essentially uniform

in composition, Fa29_31 and Fs27, respectively. Plagioclase

(Anu0r5.13) is coarse and abundant; the reason for the variation

in the orthoclase content is not known.

PCA82507 (479 g).—A black fusion crust covers most of

this stone (6 x 6 x 6.5 cm). Areas not covered by fusion crust

have a brownish color. Many chondrules are visible, the largest

being 5 mm in diameter. The interior consists of a bluish gray

matrix with white and dark gray inclusions up to 1 mm in size.

There is little obvious metal. Chondritic structure is not

prominent in the thin section examined for this description:

only a few fragments of individual chondrules are present.

This section thus may not be representative of the meteorite

FIGURE 6-25.—LL6 chondrites.

as a whole. The section shows mostly a granular aggregate of

olivine and pyroxene, with minor amounts of plagioclase,

troilite, and a little (-1%) nickel-iron. The thin section reveals

no evidence of weathering. Fusion crust (0.4 mm thick) rims

part of the section. Microprobe analyses give the following

compositions: olivine, Fa30; pyroxene, Fs^; plagioclase, Ann .

TIL82402 (476 g).—Black fusion crust covers all but the

edges of this cuboidal meteorite (7x6x 6 cm). The interior

consists of light gray matrix with dark and light inclusions. In

thin section the chondrules are sparse and poorly developed,

tending to merge with the granular groundmass, which consists

largely of olivine and pyroxene, with minor amounts of

plagioclase, troilite, and a little (-2%) nickel-iron. The section

shows a brecciated structure, with medium- to fine-grained

clasts. Weathering is minor, being limited to a little brown

limonitic staining around metal grains. Microprobe analyses

give the following compositions: olivine, Fa^; pyroxene,

plagioclase, An10.
50 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-26.—Photomicrographs of thin sections of LL6 chondrites (each field of view is 3 x 2 mm): a,

PCA82607; b, TIL82402. The chondritic structure is almost completely erased by extensive brecciation and

integration with the granular matrix.

CLASS "H?" ACAPULCO-LIKE

FIGURE 6-27

ALHA81261 (11.8 g).—A brown and black fusion crust

encloses about 50% of this small stone (2 x 1.5 x 1.5 cm). The

interior is light to medium gray, with abundant metal grains

being visible. A weathering rind is present. The thin section

shows that this meteorite is an equigranular (grains 0.1-0.4

mm across) aggregate of approximately equal amounts of

FIGURE 6-27.—Photomicrograph of thin section of the "H?" Acapulco-like

chondrite ALHA81261 (field of view is 3 x 2 mm). This meteorite is an

equigranular aggregate consisting mainly of olivine, orthopyroxene, and

plagioclase (white to gray), with minor amounts of nickel-iron, troilite, and

chromite.

olivine and orthopyroxene, with minor amounts of nickel-iron,

plagioclase, troilite, diopside, and accessory chromite. A little

limonitic staining is present around metal grains. Microprobe

analyses show that the mineral are uniform in composition:

olivine, Fa n ; orthopyroxene, Wo2En87Fsn; plagioclase,

An14Or4. This specimen is identical in all respects with ALHA

77081, classed as an H? meteorite, and the two are almost

certainly paired. The mineral analyses are indistinguishable

from those of Acapulco (Palme et al., 1981).

ALHA81315 (2.5 g) is identical with ALHA 81261 in all

respects.

In the future we will refer to these meteorites, and

ALHA77081, as Class "H?" Acapulco-like.

Achondrites

EUCRTTES

FIGURES 6-28, 6-29

ALHA81313 (0.5 g).—The classification of this very small

(0.8 x 0.7 x 0.4 cm) and completely crusted stone as a eucrite

is tentative as of this writing. It is either an unusual eucrite or,

alternatively, it could be related to the shergottites. Unfortunately, most of the specimen was consumed in producing a

thin section. The section shows a granular aggregate (grains

1-3 mm in maximum dimension) of colorless plagioclase

(maskelynite) and pale gray, weakly pleochroic pyroxene with

trace amounts of nickel-iron, troilite, and chromite. A vague

impression of pyroxene-rich and plagioclase-rich layers is

present, possibly suggesting a cumulate. The pyroxene appears

to be an inverted pigeonite: orthopyroxene with small blebs

of exsolved augite. Point counting gives the following volume
NUMBER 28 51

1 cm

FIGURE 6-28.—Eucrites.

percentages: pyroxene, 54; plagioclase, 46. Microprobe analyses show the maskelynite to be essentially stoichiometric and

fairly uniform in composition, averaging An93 (Na ^ 0.6%-

1.4%, K20 <0.4%). The orthopyroxene composition is also

fairly uniform, averaging Wo3En59Fs38; A12O3 0.4%, MnO

0.9%, TiO2 0.2%, Cr2O3 0.3%. The composition of a single

augite bleb is Wo38En42Fs20. In texture and mineral chemistry

this meteorite closely resembles the Moama monomict eucrite

(Lovering, 1975). For this reason, and because its mineral

chemistry is different from that of the shergotites, Delaney and

Prinz (Chapter 8) conclude that 81313 is a eucrite and not a

shergotite as originally suggested.

TIL82403 (49.8 g).—A shiny black fusion crust encloses

70% of this achondrite (4.7 x 4 x 2 cm). The exposed

underlying surface is gray with some white and black-andwhite clasts being visible. The top surface (as oriented on the

ice) contains numerous vugs, some as large as 5 mm in

diameter. The interior matrix is light gray with small white and

darker gray clasts. One large, coarse-grained, black-and-white

clast was exposed when the meteorite was chipped. The thin

section shows a microbreccia of angular fragments (grains up

to 1.2 mm across) of pyroxene (orthopyroxene and pigeonite)

and plagioclase, in a matrix of comminuted pyroxene and

plagioclase. Plagioclase and pigeonite locally form coarse to

fine-grained ophitic intergrowths. Trace amounts of troilite and

nickel-iron are present as minute grains. Microprobe analyses

show a considerable range of pyroxene compositions, overlapping both the orthopyroxene and pigeonite fields:

W03.22En3Q40FS43.5g. Plagioclase shows a considerable range

of composition, An7793.

PCA82501 (54.4 g).— This achondrite (4.5 x 3 x 3 cm) has

areas of shiny fusion crust remaining on all surfaces. Some

sides are smooth, while others are rough and contain numerous

vugs. Areas lacking fusion crust reveal the specimen to be

coarse grained, white to dark gray in color, and with some

yellowish oxidation. No individual clasts are visible. A very
52 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-29.—Micrographs of thin sections of eucrites (each field of view is 3 x 2 mm): a, PCA81313 (white

is maskelynite, the gray is pyroxene); b, PCA82502. Note the fine-grained unbrecciated texture; c, TIL82403.

This is a microbreccia of angular fragments of pyroxene and plagioclase, in a matrix of comminuted matrix of

the same phases; note the ophitic clast; d, EET 83234. This is a microbreccia of angular fragments of pyroxene

(pale gray) and plagioclase (white); note the dark glassy clasts.

small amount of oxidation is present in the interior. The thin

section shows an ophitic intergrowth of plagioclase and

pigeonite; the plagioclase laths average about 1 mm long. Trace

amounts of troilite and nickel-iron are present as minute grains,

the metal grains commonly being surrounded by rusty limonitic

haloes. Microprobe analyses show pyroxene compositions

ranging fairly continuously from Wo4Fs57 (orthopyroxene) to

Wo21Fs41 (pigeonite), the range in En content being quite

limited. Plagioclase compositions are in the range An80_92. The

meteorite is unbrecciated in the thin section.

PCA82502 (890 g).—This meteorite consists of 3 pieces (6

x 4.5 x 2.8 cm; 4.5 x 4.3 x 3 cm; 11 x 8.5 x 8 cm) that have

areas of extremely shiny fusion crust. These 3 pieces do not fit

together, but their field relationships and their megascopic

appearances suggest they may be paired. The interiors of the

fragments have a light gray matrix with darker gray inclusions

up to several mm across. No weathering is evident, except that

the exterior surfaces are darker gray than the interior surfaces.

The thin section shows a fine-grained ophitic intergrowth of

pigeonite and plagioclase (average length of plagioclase laths

is about 0.1 mm). Small areas of somewhat coarser material

may be partly resorbed clasts of similar composition. Trace

amounts of nickel-iron and troilite are present, as minute

grains. Microprobe analyses show pyroxene compositions

ranging fairly continuously from Wo5Fs61 to Wo34Fs36, the

range in En content being quite limited. The plagioclase

composition is An7792. The meteorite is a eucrite and is

unbrecciated in thin section; it is possibly a fine-grained variant
NUMBER 28 53

ofPCA80501.

EET83229 (312 g).—This meteorite (8 x 6 x 4 cm) is

macroscopically similar to other 1983 Elephant Moraine

eucrites, with the exception of one large (4 x 3 x 0.2 cm) brown

crystalline clast. The thin section shows a typical polymict

eucrite breccia with many pyroxene, plagioclase, and opaque

mineral clasts, and a few small lithic clasts. One lithic clast

has a feldspar phenocryst, an unusual feature for a eucritic

clast. Pyroxene clasts show various degrees of exsolution,

clouding, and compositional dispersion. Feldspar clasts show

variable amounts of shock modification. Many cracks filled

with dark weathering material crosscut the section. Microprobe analyses give the following compositions: pyroxene

WO4.39En2g.goFS3j.55; plagioclase An74.93.

EET83231 (66.4 g).—This stone (5.5 x 4 x 4.5 cm) is very

angular and contains numerous vesicles; no fusion crust is

present. The thin section shows a polymict achondritic breccia

containing several fine- and very fine-grained mafic clasts.

Numerous orthopyroxene crystal fragments similar to diogenitic pyroxene are present; however, microprobe analyses

showed no pyroxenes of diogenitic composition. Mafic clasts

vary from coarse-grained subophitic basalts, with and without

optically-zoned pyroxene and feldspar, to uncommon glassy

clasts with fine crystallites. Microprobe analyses give the

following compositions: pyroxene Wo1_20En40.49Fs37.51; plagioclase An80_92.

EET83232 (211 g).—This meteorite (7 x 8 x 4.5 cm) is

macroscopically similar to the other 1983 Elephant Moraine

eucrites. In thin section it is a typical polymict eucrite breccia

with a variety of lithic clasts. Pyroxene clasts include

pigeonites with jim scale exsolution lamellae, and both clouded

and unclouded grains are present. Some pyroxene clasts have

clear zoning that mimics the irregular clast outlines, suggesting

that they were metamorphosed after brecciation. Feldspar clasts

have shock features, and some may be recrystallized. A few

feldspar clasts have abundant inclusions of clinopyroxene up

to 20 fim in size. Mafic clasts vary from coarse to very

fine-grained, and contain cloudy exsolved pyroxene. Silica

minerals in these clasts appear both as interstitial space fillings

and as coarse lath-shaped crystals that appear to crosscut the

earlier texture. No orthopyroxene was recognized. Microprobe analyses give the following compositions: pyroxene

WOj.25En424gFS43.52; plagioclase An86.93. This meteorite is a

polymict eucrite similar to EETA79004 and 79011.

EET83234 (180 g).—This specimen (7.5 x 7.5 x 3 cm) is a

fragment similar to other 1983 Elephant Moraine eucrites. It

contains a corner of a brown crystalline clast similar to that in

EET 83229, and may be a piece of that stone. The thin section

shows a typical polymict eucrite with a variety of small mafic

clasts, including extremely fine-grained and glassy ones. Most

pyroxene clasts are pigeonitic. Microprobe analyses give the

following compositions: pyroxene Wo1.33En3g.^Fs^.^; plagioclase An78_96. An unusual feature of this stone is the

presence of pyroxene clasts with blebby rather than lamellar

exsolution. These clasts (Wo6En58_62) may be similar to

pyroxene in Binda and are rare in Elephant Moraine eucrites.

EET83236 (6.4 g).—A shiny black fusion crust with flow

marks covers 60% of this stone (2x2x 1 cm). The interior is

bluish gray with numerous white and dark clasts. Several

oxidation haloes were noted. The thin section shows a lightly

brecciated medium-grained eucrite containing pyroxene in an

ophitic to subradiate texture with generally lath-like feldspar.

The pyroxene is generally inverted pigeonite, with herringbone

textures preserved locally. Both pyroxene and plagioclase

crystals are generally clouded, although a few pyroxene grains

are quite clear. The feldspar is commonly clouded in patches

and has a mottled extinction. In places it is nearly isotropic; it

therefore has been substantially shocked. Interstitial silica

minerals, troilite, chromite, and ilmenite are accessory phases.

Microprobe analyses give the following compositions: pyroxene, Woj.42En3j.39Fs25.59; plagioclase, An89.93.

EET83283 (57.3 g).—This stone (6 x 2.5 x 3 cm) is typical

of the other 1983 Elephant Moraine eucrites. The thin section

shows a typical polymict achondrite with lithic and mineral

clasts similar to the other Elephant Moraine polymict eucrites.

Lithic clasts are generally fine-grained basalts and breccia

fragments. The matrix is very dark and full of holes and cracks,

suggesting that it has been severely weathered. Microprobe analyses give the following compositions: pyroxene

Wo2_16En41.6jFs33.4g; plagioclase An8295. Some pyroxene

clasts are shocked orthopyroxene (En5565), but most are

pigeonitic with fine exsolution lamellae; none are as magnesian

as diogenetic pyroxene. This meteorite is generally similar to

EETA79004 and 79011.

HOWARDITES

FIGURES 6-30,6-31

EET82600 (247 g).—Some black pitted fusion crust is

present on one surface of this stone (7x5x 5 cm). The other

surfaces are smooth and gray with small white and dark gray

inclusions. Chipping has revealed a gray interior with an

indistinct whitish weathering rind. Inclusions are small and

not very obvious. The thin section shows a microbreccia of

angular fragments (grains up to 2 mm across) of pyroxene

(orthopyroxene and pigeonite) and plagioclase, and rare

plagioclase-pigeonite clasts up to 1.5 mm across, in a

matrix of comminuted pyroxene and plagioclase. Trace

amounts of troilite and nickel-iron are present. Microprobe

analyses show a wide range in pyroxene compositions:

WOi_24En33.77Fs22.53; the grains with En >70 indicate the

presence of a diogenitic component. Plagioclase shows a

considerable range of compositions, An7993. The meteorite is

possibly paired with EETA79006.

EET83212 (402 g).—The exterior color of this achondrite

(7 x 6 x 7 cm) ranges from medium gray to brown-gray, except

for a thin, dull-black fusion crust on two surfaces. The interior
54 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 6-30.—Howardites.

is gray and rich in clasts; the latter include black fine-grained

varieties and possibly some eucritic ones. A 1 cm thick

weathering rind was exposed when the stone was chipped. The

thin section is dominated by a single, very fine-grained mafic

clast of the type common in both Allan Hills and Elephant

Moraine polymict eucrites. Numerous smaller mineral clasts

are enclosed within this large clast. Several outer parts of this

fine-grained clast that border the coarser-grained matrix are

darker than the clast interior, either because the border region

is finer-grained or because of the presence of iron oxide

weathering products. Some mineral clasts have dark finegrained "chill zones" around them. Pyroxene grains within this

dark clast have a variety of fine- and coarse-scale exsolution

lamellae. Feldspar grains are partly maskelynitized. One

feldspar clast has a glassy core with a feldspar rim that mimics

the shape of the clast. Heating by the mafic melt that quenched

to form the dark clast apparently caused devitrification of the

previously-shocked feldspar grains. The "normal" breccia of

83212 contains breccia clasts, basaltic clasts with clouded

pyroxenes and intergranular textures, granular mafic clasts

with recrystallized pyroxene, and some glassy material. One

clast of diogenetic orthopyroxene was observed. Microprobe analyses give the following compositions: pyroxene

Wo1.35En33.80Fs18.53; plagioclase An84_96.

EET83227 (1973 g).—This meteorite (13 x 10 x 9 cm) has

a rounded shape, and the outer surfaces contain numerous deep

vugs. A few millimeter-sized patches of fusion crust remain

on the gray exterior. Several different kinds of clasts are visible,

the largest being 2 cm in length; they include eucritic clasts,

black fine-grained clasts, pinkish brown fine-grained clasts,

and black and white clasts. Both interior and exterior surfaces

show numerous oxidation haloes up to 1 cm in diameter.

Interior surfaces are lighter gray than the exterior ones. The

thin section reveals a typical polymict achondrite, with one

large medium-grained mafic clast containing ophitic to radial

pyroxene/plagioclase intergrowths. The pyroxene and plagioclase in this clast are zoned and show little clouding. Other

clasts include breccia, shocked pyroxene, and twinned feldspar.

No maskelynite was observed. Coarse-grained lithic fragments,

fine-grained granular mafic clasts and rare glassy fragments

are also present. Microprobe analyses give the following

compositions: pyroxene, Woj.39En3Q.73FS23.54*, plagioclase,

An7898. The occurrence of pyroxene grains with En >70

indicates the presence of a diogenitic component in this

meteorite.

EET83228 (1206 g).—One small patch of black fusion crust

remains on this moderately fractured meteorite (12.5 x 11.5 x

8.5 cm). Exterior surfaces are darker gray than interior ones;

many areas are heavily oxidized. Numerous deep vugs are

present on all of the exterior surfaces. Abundant clasts of

various types are readily apparent. The thin section shows a

polymict eucrite with a variety of generally small lithic clasts.

These latter include types seen in both howardites and polymict

eucrites, ranging from medium- and coarse-granular clasts to

interstitial basalts. Microprobe analyses give the following

compositions: pyroxene, Wo1_25En32_80Fs18_54; plagioclase,

An8294. A few large orthopyroxene clasts have concentric

zoning (cores are En70_75), suggesting exchange reactions with

the surrounding breccia. These modified clasts are similar to

clasts in EETA 79004, with which this meteorite may be paired.

EET83235 (254 g).—This meteorite (7 x 6 x 4 cm) looks

similar to the other 1983 Elephant Moraine eucrites except

that it appears to be more heavily weathered, as indicated by

the presence of a thick dark gray weathering rind. The thin

section shows a very dark gray matrix that appears to have

been modified by this weathering, as sulfate is present. One

pyroxenite clast contains two large (-1 mm) pyroxene crystals

showing no exsolution; this may be a fragment of an

orthopyroxenite, but shock modification has produced inclined

extinction in the pyroxene. Feldspar clasts also show abundant

evidence of shock. Pigeonite clasts are abundant, in which the
NUMBER 28 55

FIGURE 6-31.—Photomicrographs of thin sections of howardites (each field of view is 3 x 2 mm): a, EET82600.

This is a microbreccia of orthopyroxene, pigeonite, and plagioclase in a comminuted matrix of pyroxene and

plagioclase. Note the small gabbroic clast. b, EET83228. This is similar to 82600; note the dark glassy clasts.

pyroxene shows [im-scale exsolution. One mafic clast has a

gabbroic texture and contains lath-shaped tridymite (?) crystals

over 1 mm in length. Other clasts are extremely fine-grained

or glassy. Microprobe analyses give the following compositions: pyroxene, Wo1_3gEn22_72Fs26_54; plagioclase, An8696. One

large diogenitic clast was analyzed in which the pyroxene is

Wo2, En72, Fs26.

EET83251 (261 g).—This stone (7 x 5.5 x 4 cm) is another

typical example of the 1983 Elephant Moraine polymict

achondrites. The thin section shows a wide variety of clast

types, including medium- to coarse-grained gabbroic clasts

with zoned pyroxene and plagioclase crystals, fine-grained

basaltic clasts, glassy (or devitrified) clasts, breccia and

recrystallized breccia clasts, pyroxene-rich mafic and breccia

clasts, and orthopyroxene clasts (some containing orthopyroxene as magnesium-rich as Eng5). One coarse-grained mafic

clast contains anhedral feldspar crystals (>200 Jim in size)

with 1-10 jim-sized inclusions of clinopyroxene, a feature

generally seen only in monomineralic feldspar clasts in

Victoria Land achondrites. Microprobe analyses give the

following compositions: pyroxene, Wo1.28En37.85Fs14,58; plagioclase, An80.95.

UREILITES

FIGURES 6-32,6-33

ALH82106 (35.1 g), 82130 (44.6 g).—Patches of black

fusion crust cover much of the surfaces of these two specimens.

Exposed interior surfaces are black with moderate to heavy

oxidation. Well-developed crystal faces are obvious. The thin

sections show an aggregate of anhedral to subhedral grains

(0.3-1.8 mm across) of olivine (about 60%) and pyroxene

(about 30%), with about 10% of opaque material that is in part

disseminated throughout and in part concentrated along grain

boundaries. Both olivine and pyroxene show undulose

extinction, suggesting that the specimens have been shocked.

Olivine grains are gray from submicroscopic opaque inclusions, whereas pyroxene grains are clear but are extremely

fractured. The opaque material along grain boundaries consists

of graphite and secondary iron oxides. Microprobe analyses

give the following compositions: olivine is somewhat variable,

with a range of Fa^g and a mean of Fa3; pyroxene is essentially

uniform, Wo5En91Fs4, although one grain of sub-calcic augite

was analyzed that has the composition Wo36En62Fs2. The

mineralogy and textures of these two stones are typical of

ureilites, but the minerals have higher Mg/Fe ratios than those

in any ureilite so far described.

ALH82130 is essentially identical to ALH82106 in all

respects and can confidently be paired with it.

Goodrich and Berkley (1985) have reported precise determinations for Ti, Al, Cr, Mn, Ca, P, and Ni in the cores of olivine

crystals from this meteorite.

ALH83014 (1.3 g).—Weathered fusion crust covers part of

this small ureilite (1 x 0.5 x 0.5 cm). Well-developed crystal

faces are apparent on other surfaces. The overall color is

reddish brown. The thin section shows an aggregate of rounded

to subhedral grains (0.6-3 mm across) of olivine with minor

pyroxene. Small platy crystals of graphite are present in

carbonaceous rims around the silicate grains. Trace amounts

of troilite and nickel-iron are present, the latter being largely

altered to translucent brown limonite. Microprobe analyses

show olivine of uniform composition (Fa18) with notably high

CaO (0.4%) and Cr2O3 (0.7%) contents; the pyroxene is a

pigeonite of composition WOgEn^Fs^. This meteorite appears
56 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

EET 83225 ,0

FIGURE 6-32.—Ureilites.

to be relatively unshocked compared to most ureilites.

PCA82506 (5316 g).—Patches of fusion crust cover 75%

of the surface of this large achondrite (22 x 16 x 9 cm); in

places this fusion crust has a blistery texture. Areas with little

fusion crust are greenish to brown; the interior is grayish green

to brown. The matrix has a blocky texture and many crystal

faces are evident. The thin section shows an aggregate of

anhedral to subhedral grains (0.6-3 mm across) of olivine and

pyroxene. Individual grains are rimmed by carbonaceous

material, included within which are thin stringers of troilite.

Trace amounts of nickel-iron have been largely weathered to

limonite. Microprobe analyses show olivine of uniform

composition (Fa21) with notably high CaO content (0.3%); the

pyroxene is pigeonite with composition Wo6En76Fs18. Some

grains show undulose extinction but this meteorite is otherwise

relatively unshocked compared to most ureilities.

Goodrich and Berkley (1985) have reported precise determinations of Ti, Al, Cr, Mn, Ca, P, and Ni in the cores of olivine

crystals from this meteorite. Berkley and Goodrich (1985)

described cohenite-bearing metallic spherules. Miyamoto et al.

(1985) have estimated a cooling rate of 10°/hour from an initial

temperature of 1200° ± 50° C down to a final temperature of

800° C.

EET83225 (44.0 g).—The surface of this meteorite (5 x 2.5

x 2.5 cm) is covered with a very thin and smooth fusion crust,

which is brownish black with a dull sheen. Well-developed

crystals make up the interior, which is heavily oxidized to a

reddish brown color. The thin section reveals a medium- to

coarse-grained ureilite composed of generally clear crystals of

olivine (Fan) and pyroxene (Wo10En77Fs13), with the pyroxene

predominant in abundance. Grain boundaries are coated with

dark material containing vein-like metal, graphite, and a

yellow/red cathodoluminescent phase that is probably diamond. Tiny metallic inclusions occur in some olivine and

pyroxene grains. The section shows a distinct, dimensionallydependent, preferred orientation of both pyroxene and olivine,

suggesting cumulus structure.

AUBRITES

FIGURE 6-34

ALH83009 (1.7 g), 83015 (3.1 g).—These two small white

specimens appear visually to be identical, and this is confirmed

by petrographic examination. Both consist almost entirely of

orthopyroxene clasts up to 5 mm in size set in a comminuted

groundmass of the same mineral. One grain was found that has

inclined extinction and appears to be clinoenstatite. Accessory

minerals include olivine, plagioclase, nickel-iron, troilite,

daubreelite, and alabandite. Rusty haloes surround the metal

grains. Microprobe analyses show that the olivine and

pyroxene are essentially pure magnesium silicates: olivine FeO

~0%-0.06%; pyroxene FeO ~0%-0.17%; CaO ~0.05%-0.46%

with a mean of 0.26%. Plagioclase is An90Or3. Silicon was not

detected in the metal. ALH83009 differs from ALHA78113

in not having the dark clasts observed in the latter meteorite.

DlOGENITES

FIGURES 6-35,6-36

ALHA81208 (1.6 g).—An evaporite deposit coats the

oxidized fusion crust that totally covered this small stone (2.1

x 1 x 0.5 cm). The stone crumbled when it was chipped,

revealing the interior to be completely weathered. The thin

section consists almost entirely of orthopyroxene clasts,

ranging up to 3 mm in maximum dimension, with accessory

chromite. The individual clasts are rimmed by dark brown to

black material, which consists in part of limonite. Remnants

of fusion crust are present in the thin section, and have an outer

crust of brown limonite. Microprobe analyses show that the
NUMBER 28 57

FIGURE 6-33.—Photomicrographs of thin sections of ureilites (each field of view is 3 x 2 mm): a, ALH82106;

b, PCA82506; c, ALH83014; d, EET83225. Note the distinctly different textures in these four ureilites.

pyroxene is essentially uniform in composition, except for

some variation in calcium content (CaO 1.2%-2.5%); the mean

composition is Wo3En72Fs25, with 0.7% A12O3, 0.14% TiO2,

and 0.6% MnO. The meteorite is classified as a diogenite,

although the amount of limonite suggests that it may be a

silicate fragment from a mesosiderite. It is therefore listed in

the Appendices to this volume as a diogenite/mesosiderite.

TIL82410 (18.8 g).—A dull, blistery fusion crust covers one

surface and is present in patches on other surfaces of this stone

(3x2.5xl.5cm). Areas without fusion crust have a pinkish

tinge. Mineral clasts up to 5 mm in longest dimension are

abundant, as are gray veins (1-5 mm wide), which stand out

FIGURE 6-34 {Left).—Photomicrograph of thin section of the aubrite

ALH83015 (field of view is 3 x 2 mm). This is a microbreccia consisting

almost entirely of enstatite crystals.
58 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

in relief relative to the surrounding material. A single green

crystal and several reddish brown grains are present. The thin

section shows angular clasts of pyroxene, up to 3 mm in

greatest dimension, in a groundmass of comminuted pyroxene.

The only other minerals noted were rare grains of plagioclase

and trace amounts (less than 1%) of nickel-iron. Remnants of

fusion crust are present along one edge. The section is stained

brown with limonite. Microprobe analyses show the pyroxene

to be uniform in composition: Wo2En74Fs24, with 0.47%

A12O3, 0.64% MnO, and 0.07% TiO2.

EET83246 (48.3 g).—Shiny patches of fusion crust cover

one surface and dull pitted fusion crust covers the opposite

surface of this meteorite (4 x 3.5 x 2 cm). A highly polished

FIGURE 6-35 (Right).—Diogenite. Areas of black fusion crust have flaked off,

revealing coarsely crystalline orthopyroxene.

EET 83246

FIGURE 6-36.—Photomicrographs of thin sections of diogenites (each field of view is 3 x 2 mm): a, ALHA81208;

b, TIL82410; c, EET83246; d, EET83247. Note the distinctly different textures in these four diogenites.
NUMBER 28 59

fracture surface exposes the greenish gray crystalline interior.

Many clasts are visible, the largest of which is 1 cm long. The

thin section shows clasts of orthopyroxene up to 9 mm long,

in a groundmass of comminuted pyroxene and accessory

chromite, troilite, and nickel-iron. The pyroxene is very

uniform in composition, Wo2 6En73 ^s^ , with 0.7% A12O3 and

0.5% MnO.

EET83247 (22.5 g).—Shiny black fusion crust covers about

one quarter of the surface of this specimen (4 x 2.5 x 1.5 cm).

About half of the exterior surface has weathered to a reddish

brown, and the remainder is medium gray with large

cream-colored clasts. One fine-grained black clast was also

noted. Most of the exposed interior has been heavily oxidized.

The thin section shows a cataclastic texture, and there is a

continuous range in clast size from less than 0.1 mm to 2 mm.

The meteorite consists almost entirely of orthopyroxene, with

accessory amounts of chromite, troilite, and nickel-iron. Brown

limonitic staining pervades the section. The pyroxene is

uniform in composition, Wo2En75Fs23, with 0.6% A12O3 and

0.5% MnO.

These two EET diogenites are not paired, and appear to be

different from the other Elephant Moraine diogenite, EETA79002.

ACHONDRTTE, UNCLASSIFIED

FIGURE 6-37

ALHA81187 (40.0 g).—Several cracks penetrate the mostly

weathered interior of this stone (4.5 x 2.5 x 2 cm). Fusion crust

covers two surfaces, one of which shows remnants of flow

features. The thin section shows an aggregate of anhedral to

subhedral grains, 0.05-0.6 mm across, of pyroxene to olivine,

with about 20% of disseminated nickel-iron and minor amounts

of plagioclase, troilite, and schreibersite. The proportion of

pyroxene to olivine is estimated at 4:1. Weathering is

extensive, with veinlets and small areas of brown limonite

throughout the section. Microprobe analyses give the following

compositions: olivine, Fa4; pyroxene, Wo3En90 5Fs6 5; plagioclase, Anlg. The meteorite is tentatively considered to be an

achondrite (unclassified), but it may belong to the small group

of forsterite chondrites (Graham et al., 1977).

Literature Cited

Antarctic Meteorite Newsletter, 6(2).

Antarctic Meteorite Newsletter, 8(1).

Antarctic Meteorite Newsletter, 8(2).

Berkley, J.L., and C.A. Goodrich

1985. Cohenite-bearing Metallic Spherules in Ureilites: Petrology and

Implications. In Lunar and Planetary Science XVI, pages 49-50.

Houston: The Lunar and Planetary Institute.

FIGURE 6-37.—Photomicrograph of thin section of the unclassified achondrite

ALHA81187 (field of view is 3 x 2 mm). It consists mainly of olivine and

orthopyroxene, with minor plagioclase (white to gray), some nickel-iron and

troilite.

Dodd, R.T, Jr., W.R. Van Schumus, and D.M. Koffman

1985. A Survey of the Unequilibrated Ordinary Chondrites. Geochimica

et Cosmochimica Acta, 31:921-951.

Goodrich, C.A., and J.L. Berkley

1985. Minor Elements in Ureilites: Evidence for Reverse Fractionation

and Interstatial Silicate Liquids. In Lunar and Planetary Science

XVI, pages 280-281. Houston: The Lunar Planetary Institute.

Graham, A.L., A.J. Easton, and R. Hutchison

1977. Forsterite Chondrites; the Meteorites Kakangari, Mount Morris

(Wisconsin), Pontlyfini, and Winona. Mineralogical Magazine,

41:201-210.

Lovering, J.F.

1975. The Moama Eucrite—A Pyroxene-Plagioclase Adcumulate. Meteoritics, 10:101-114.

Miyamoto, M., H. Toyoda, and H. Takeda

1985. Thermal History of Ureilite as Inferred from Mineralogy of Pecora

Escarpment 82506. In Lunar and Planetary Science XVI, pages

567-568. Houston: The Lunar and Planetary Institute.

Palme, H., L. Schultz, B. Spettel, H.W. Weber, H. Wanke, M. Christophe

Michael-Levy, and J.C. Lorin

1981. The Acapulco Meteorite: Chemistry, Mineralogy and Irradiation

Effects. Geochimica et Cosmoshimica Acta, 45:727-752.

Scott, E.R.D.

1985. Further Petrologic Studies of Metamorphosed Carbonaceous Chondrites. In Lunar and Planetary Science XVI, page 748. Houston: The

Lunar and Planetary Institute.

Van Schumus, W.R., and J.A. Wood

1967. A Chemical-Petrographic Classification System for the Chondritic

Meteorites. Geochimica et Cosmochimica Acta, 31:747—765.

Wieler, R., H. Baur, Th. Graf, and P. Signer

1985. He, Ne, and Ar in Antarctic Meteorites: Solar Noble Gasses in an

Enstatite Chondrite. In Lunar and Planetary Science XVI, pages

902-903. Houston: The Lunar Planetary Institute.
7. Descriptions of Some Antarctic Iron Meteorites

Roy S. Clarke, Jr.

This chapter provides brief descriptions of three octahedrites

and two ataxites that were collected during the 1983 field

season. The descriptions are preliminary and are based on

material prepared for publication in the Antarctic Meteorite

Newsletter. Previously unpublished chemical values by Eugene

Jarosewich are included for three of the specimens.

Octahedrites

EET83245 (59 g).—This specimen (5.5 x 2.5 x 1.3 cm) from

Elephant Moraine has a smoothly curved top surface that meets

a flat bottom surface at one side, and an irregular narrow

surface that is perpendicular to the bottom surface on the

opposite side. The shield-shaped specimen is completely

covered with a reddish brown coating of terrestrial iron oxides.

No remnant fusion crust was visible. The curved surface

appears to have been an exposed surface during weathering:

wind ablated, polished, and slightly pitted. The other two

surfaces are more deeply corroded.

A slice from near one end of the specimen yielded a 1.4 cm2

metallographic section of mainly kamacite. The wind-ablated

surface was also an ablation surface during atmospheric

passage, as it has a heat-altered zone extending at least 1 mm

into the interior. Fusion crust, however, has been removed by

weathering. The bottom surface appears to consist of either

weathered fusion crust or, more likely, weathered melt material

that filled a crack during atmospheric heating. Some interior

material along this bottom surface is also heat altered.

Microrhabdites occur in abundance throughout, with occasional rhabdites and very thin lamellar schreibersites along

subgrain boundaries. One grain boundary contains schreibersite and heat-altered taenite. The presence of taenite in what

appears to be a relatively large mass of kamacite suggests that

this specimen is a fragment of a coarsest octahedrite. A bulk

value of 6.1 weight percent Ni is consistent with a I IB chemical

classification.

EET83333 (188 g).—This specimen (5 x 4 x 2.5 cm) from

Elephant Moraine is irregularly shaped, weathered and pitted,

Roy S. Clarke, Jr., Department of Mineral Sciences, National Museum

of Natural History, Smithsonian Institution, Washington, DC. 20560.

and mostly covered with a reddish brown coating of secondary

oxides. Tiny areas of remnant fusion crust have been preserved

in several depressions. Silicates are exposed at the bottoms of

other depressions, the largest silicate area measuring 10 x 5

mm. Ablative melting of inclusions appears to have caused

other surface depressions.

A median section through the specimen provided an area of

approximately 8 cm2 for examination (Figure 7-1). The surface

is silicate-rich, containing a number of millimeter-sized silicate

regions as well as numerous smaller individual crystals

unevenly distributed in the metal. Silicate associations

comprise 5%-10% of the surface area, two clusters having

maximum dimensions of 5 mm. The metal is polycrystalline

kamacite with individual crystals in the millimeter-size range.

Longest dimensions are normally less than 5 mm, and the

shortest normally more than 1 mm. Taenite and pearlitic

plessite areas are distributed along grain boundaries and at

junctions of three or more kamacite grains. A striking feature

of this meteorite, readily visible on the etched surface shown

in Figure 7-1, is a continuous and unusually thick circumferential heat-altered zone. The thickness of the a 2 structure

averages about 5 mm and ranges from 2 to 7 mm. About half

of the area of the slice is heat altered. Although small areas of

fusion crust were tentatively identified in surface depressions,

none was recognized in polished section. Weathering is most

obvious near the surface and has penetrated into the interior

along grain boundaries.

Interior kamacite areas contain numerous straight Neumann

bands and numerous curved subboundaries. Subboundaries are

populated with occasional schreibersites, some of which have

distinct rhabdite morphologies. Kamacite areas tend to be

mottled, suggesting the presence of unresolvable microrhabdites. Large schreibersites occur along crystal boundaries, and

several areas of massive schreibersite occur in association with

silicate-graphite-troilite areas. Schreibersite also occurs at

taenite borders. The plessite has a well-developed pearlitic

structure and is present in abundance, consistent with a medium

or coarse octahedrite. A distinct Widmanstatten pattern is not

sufficiently well developed to obtain reliable band widths.

Silicate areas contain coarse (0.1 to 0.5 mm), colorless, and

transparent crystals associated with abundant troilite and traces

61
62 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 7-1.—Polished and etched surface of EET83333. The mottled gray rim

zone is atmospherically heat-altered to a depth of 7 mm at one point. The dark

gray inclusions are silicate-graphite-troilite areas. Kamacite grain boundaries

and areas of Widmantatten pattern may also be seen. The maximum width of

the slice is 4 cm.

of included kamacite and taenite. Graphite occurs in some of

the silicate areas, generally at silicate/metal interfaces, and it

is coarse-grained where present. All the troilite in this section

occurs with silicates. Survey electron microprobe examination

of the silicates identified plagioclase (An9), olivine (Fa5), and

pyroxene (Fs7).

This individual is a silicate-rich octahedrite, probably a

Group I iron. The unusually thick heat-altered zone suggests

an atypical passage through the atmosphere.

EET83390 (15.1 g).—This specimen (2 x 1.8 x 1 cm) from

Elephant Moraine is irregular in shape and deeply weathered.

The surface is covered with reddish brown secondary oxides,

and contains several small depressions that may have resulted

from atmospheric melting.

A median section provided an area of 1 cm2 for examination.

The structure revealed is that of a heat-affected octahedrite,

either a medium or coarse octahedrite. The few structures

available for band width measurements indicate a 1 to 1.5

mm range. Throughout the section kamacite has been

transformed to a 2 by atmospheric heating. Most of the rim of

the section is coated with layered secondary oxides from 0.1

to 1 mm thick.

Taenite and comb plessite areas also appear to have been

somewhat heat-affected. Microrhabdites are present, and

several remant Neumann bands are suggested by linear arrays

of microrhabdites. Major grain boundaries are populated over

much of their lengths by either grain boundary schreibersite

or secondary iron oxides that have invaded the interior. Some

schreibersite is associated with taenite-plessite areas.

This specimen appears to be a small individual that was

severely heated upon passage through the atmosphere. It is an

octahedrite and may prove on further study to be a Group III

iron.

Ataxites

EET83230 (530 g).—This specimen (5.5 x 5 x 5 cm) from

Elephant Moraine is a rounded, and roughly equidimensional

individual, reminiscent of a small cobble. It is completely

covered with a secondary reddish brown coating of iron oxides,

and no traces of fusion crust remain. The surface that has been

recently exposed to wind ablation in our atmosphere is slightly

smoother than the other surfaces, having rounded edges and a

slightly distorted rectangular outline.

A slice through one side of the specimen produced a 15 cm2

surface for examination. The matrix is martensitic, containing

a few widely dispersed kamacite spindles. An occasional

spindle will contain a very small schreibersite. The section's

most interesting feature is a concentration, in one half of the

slice, of about a dozen mm-sized iron phosphate crystals

(Figure 7-2), some with euhedral outline and/or enclosed

troilite. These inclusions are partially bordered by thin

kamacites.

This individual is an unusual phosphate-rich ataxite with a

bulk value of 16.1 weight percent Ni.

ILD835OO (2523 g).—This specimen (13.5 x 12 x 4 cm)

was found near Inland Forts by Bob Ackert of the University

of Maine at Orono. It was found "imbedded in loose sandy till

with abundant pebbles and cobbles of the Beacon Sandstone

and dolorite. The glacial deposit overlies the Beacon Sandstone. The top of the white evaporite deposit marks the depth

at which the iron was buried" (Figure 7-3). The specimen is

flat with an outline similar to that of a policeman's badge. It

has three distinct surface types. The exposed surface as found

is slightly irregular and covered with a scaley reddish brown

to dark reddish brown iron oxide coating. This surface is

bordered on the sides by a <1 cm thick band of cream-colored

soil and clay. The sides and bottom of the specimen below this

band have a much different appearance. These surfaces are

rough, range in color from black to reddish brown, and have

numerous adhering soil particles and sand grains.

A metallographic surface of 9 cm2 was prepared for

examination. The most prominant features in the martensitic

matrix are centimeter-long lamellar inclusions that appear to

be oriented according to parent taenite crystallography. They

have thin kamacite borders that occasionally enclose schreibersite. Most appear to have contained very thin cores that have

been replaced by oxides due to weathering. The best preserved

of these lamellae contain cores of chromite a few microns thick.

The matrix contains a high concentration of -50 jim-sized

schreibersite grains surrounded by kamacite. The orientation

of the kamacite seems to have been controlled by schreibersite

precipitation. Several troilites are present in association with

lamellar and/or equidimensional chromite. A very small crystal

tentatively identified as tridymite was found within troilite, at

its border with kamacite.

This specimen is an unusual ataxite with a bulk value of

18.9 weight percent Ni.
NUMBER 28 63

FIGURE 7-2.—A large crystal of FejtPO^ in EET83230 photographed in

reflected light. A martensitic matrix surrounds the phosphate, as does a thin rim

of kamacite. Troilite intrudes into the center of the crystal. The maximum

length between crystal edges is 0.7 mm.

FIGURE 7-3.—ILD835OO was found partially within soil near Inland Forts. The

dark surface area is typical of weathered meteoritic iron that has been exposed

to the atmosphere, developing a thin coating of pitted, reddish brown iron

oxides. The light-colored areas along the left side and bottom of the photograph

were in soil. Weathering was more severe and soil particles still adhere.

Maximum length is 15 cm.
8. Overview of Some Achondrite Groups

Jeremy S. Delaney and Martin Prinz

Introduction

Many meteorites have been collected in Antarctica during

every field season between 1976 and 1984 (Table 8-1). Prior

to 1969, only four meteorites from Antarctica were known

(Hey, 1966; Hutchison et al., 1977), but since then nearly 6700

samples have been collected from several sites all over the

Antarctic continent. Most of the samples collected are ordinary

chondrites, but numerous achondritic samples have also been

collected (Table 8-2).

Achondritic meteorites have been collected at localities near

the Transantarctic Mountains from latitudes 76°S in Victoria

Land to 80°30/S in the Thiel Mountains-Pecora Escarpment

region. For brevity, all the meteorites collected by American

expeditions to Antarctica are described as "Victoria Land"

achondrites since most of the meteorite deposits (away from

the Yamato Mountains area) are in Victoria Land. Studies of

meteorite suites are reviewed and some emphasis is given to

new samples from the 1983 season that have not yet been

widely studied. The Victoria Land achondrites sample all the

known achondritic meteorite suites and include several unique

meteorite types. (Note that the terms "sample" and "meteorite"

are not used interchangeably in this study. A sample is taken

to mean one individual fragment that has been or can be

assigned a sample number such as those in Table 8-3. A

meteorite, however, is taken to consist of one sample or several

samples that are parts of the same original fall. The number

of samples available is, therefore, larger than the number of

meteorites that are represented by these samples.)

The most common achondrite samples are the basaltic

achondrites (44 samples). Of these, the polymict achondrites

are the most abundant (31 samples). There are only seven

eucrites and five diogenites. Ureilites are the next most

abundant type (11 samples) and other achondrite groups are

represented by smaller numbers of samples. Specimens of the

shergottite-nakhlite-chassingite group have been collected in

Victoria Land but are omitted from this review. Table 8-3

includes the mesosiderite sample numbers, since these stony

Jeremy S. Delaney and Martin Prinz, Department of Mineral Sciences,

American Museum of Natural History, New York, New York 10024.

irons have a basaltic achondrite silicate fraction. The 70

achondrite samples in Table 8-3 do not represent 70 meteorites.

Many samples may be grouped as a single meteorite. In

particular, the polymict basaltic achondrites appear to be

samples of four to six meteorite showers, each represented by

one to many samples (Delaney, O'Neil, et al., 1984).

The problem of determining the number of meteorite falls

has been addressed using several different techniques: field

relations (Marvin, 1984), petrography (Delaney, Takeda, Prinz,

et al., 1983; Delaney, O'Neil, et al., 1984a; Delaney, Prinz, et

al., 1984), chemical composition (Reid and Le Roex, 1984;

Fukuoka, 1984), terrestrial ages (Webster et al., 1982; Schultz

and Freundel, 1984). The total number of samples associated

with each fall is presently unknown, but the achondrite

specimens from the Victoria Land sites (Table 8-3) are

probably samples of fewer than 30 meteorites, distributed

among eight achondrite types. More than half of the specimens

are polymict eucrites.

Basaltic Achondrites

The number of basaltic achondrite samples (eucrites,

polymict eucrites, howardites, diogenites) from Victoria Land

continues to grow rapidly. The number of well-distinguished

meteorites is, however, fairly small as most samples may

almost certainly be grouped as members of showers or as

fragments of broken meteorites.

The Victoria Land basaltic achondrites are generally similar

to the non-Antarctic meteorites. The most abundant nonAntarctic suites are eucrites and polymict achondrites and these

are also the most important Victoria Land suites. Diogenites,

members of a closely related achondrite group, are also

represented in both suites. Statistical analyses comparing the

number of non-Antarctic falls with Victoria Land finds for

each achondrite group suggest that the Antarctic samples are

derived from a similar population to the present day meteorite

influx. In general, similarities between the Antarctic meteorite

collections and the non-Antarctic collection seem to be

increasing as the number of Antarctic meteorites increases.

65
66 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 8-1.—Number of meteorite specimens collected at Antarctic localities.

Year

1969

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

Total

VanYear

1969

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

Total

Allan

Hills

-

-

-

9

307

262

54

32

315

145

102

17 +

1243

Outpost

Nun.

_

-

-

-

-

-

-

-

1

-

-

-

-

1

Bates

Nun.

-

-

-

-

-

4

-

-

-

-

-

-

4

Pecora

Esc.

_

-

-

-

-

-

-

-

-

-

29

-

-

29

Belgica

Mtn

-

-

-

-

-

-

5

-

-

-

-

-

5

Purgatory

Peak

_

_

-

-

-

1

-

-

-

-

-

-

-

1

Derrick

Peak

-

-

-

-

-

9

-

-

-

-

_

-

9

Reckling

Peak

-

-

-

-

-

4

15

68

-

-

-

-

87

Inland

Forts

-

-

-

-

-

-

-

-

-

-

1

-

1

Taylor

Glac.

-

-

-

-

-

-

-

-

-

1

-

-

1

Elephant

Moraine

-

-

-

-

-

-

10

-

-

17

84

-

I ll

Thiel

Mtn

-

-

-

-

-

-

-

-

-

16

-

-

16

Meteorite

Hills

_

-

-

-

-

-

28

-

-

-

-

_

-

28

Yamato

Mtn

9

12

663

307

_

-

-

3676

13

133

211

42

58

5124

Mount

Baldr

-

-

-

2

-

-

-

-

-

-

_

-

2

NOTES.—Achondrite classes not represented in Antarctica: 1, nakhlites; 2, angrites; 3,

chassignites. Nun. = Nunatak; Glac. = Glacier, Esc. = Escarpment; Mtn = Mountains.

Meteorites found before 1969: Adelie Land; Lazarev; Thiel Mtn; Neptune Mtn.

TABLE 8-2.—Number of achondritic meteorites from Victoria Land.

Type

Lunar

Shergottites

Aubrites

Ureilites

Winonaites

Eucrites

Diogenites

Polymict

eucrites

Allan

Hills

1

1

3

-

1

1

1

2-3

Elephant

Moraine

_

1

-

1

-

1

3

2-3

Reckling

Peak

_

-

-

1

-

2

-

-

Pecora

Escarp.

_

-

-

1

-

2

-

-

Thiel

Mtn

_

-

-

-

-

1

1

-
NUMBER 28 67

Type

TABLE 8-3.—Victoria Land achondrites sample numbers.

Numbers

Lunar A81005

Winonaites A81187

Aubrites A78113, A83OO9, A83015

Shergottites A77005, E79001

Diogenites A77256, E79002, T82410, E83246, E83247

Eucrites R80204, R80224, A81011(?), A81313(?), T82403, P82501,

P82506, E83236

Ureilites A77257, A78019, A78262, R80239, A81101, P82506,

A82106, A82130, A83014, E83225

Mesoside- A77219, R79015, R80229, R80246, R80258, R80263,

rites R81059,R81098(?), A81028

Polymict A76005, A77302, A78006(?), A78040, A78132, A78158,

eucrites A78165, A79017, A80102, A81001(?), A81006, A81007,

A81008, A81OO9(?), A81010, A81012, E79004, E79005,

E79006, E79011, E82600(?), E83212, E83227, E83228,

E83229, E83231, E83232, E83234, E83235, E83251,

E83283

NOTES.—Numbers followed by (?) have been given different classifications

in Antarctic Meteorite Newsletters. A, E, P, R, T, are Allan Hills, Elephant

Moraine, Pecora Escarpment, Reckling Peak, Thiel Mountains, respectively.

COMPARISON OF ANTARCTIC AND NON-ANTARCTIC BASALTIC

ACHONDRITES

Although there are overall similarities, there are some

differences in detail, between the Antarctic and non-Antarctic

samples. The most important of these are between the suites

of polymict achondrites. These meteorites sample a continuum

of breccias that represent the crust and regolith of at least one

basaltic achondrite parent body, and are dominated by two

lithological components that are present in varying proportions:

orthopyroxenites and mafic rocks. Minor amounts of other

rock types are also present. The presence and amount of these

two main components is used as a basis for classifying the

polymict basaltic achondrites and, therefore, a brief description

of each is given.

ORTHOPYROXENITES.—This component is represented by

mineral clasts of orthopyroxene with compositions similar to

diogenetic pyroxene (En70_75) and very rare lithic clasts of

orthopyroxenite containing variable but minor amounts of

olivine, chromite, troilite, and metal. The range of pyroxene

compositions (En70.86) sampled by the polymict achondrites is,

however, greater than that of the diogenites. The orthopyroxenite component of these meteorites, therefore, cannot be simply

equated with the diogenites as they are represented by the

present meteorite collections. Study of pyroxene-rich achondrites from the Yamato collections of Antarctic achondrites

has extended the range of compositions in pyroxenitic

meteorites toward more iron rich pigeonitic compositions

(En6070) (Takeda and Mori, 1984). Some of these Yamato

samples are comparable with the Binda pyroxene-rich cumulate

and appear to represent a transitional facies between the

orthopyroxenite and mafic components of polymict achondrites (Takeda and Mori, 1984). There are no unbrecciated or

monomict achondrites as magnesian as the most magnesian

orthopyroxenes (En80+) found in polymict achondrites.

MAFIC CLASTS.—The most common type of mafic clast in

polymict achondrites is eucritic and has approximately equal

volumes of pigeonite and plagioclase with compositions

similar to the eucrites (En30.40Wo4.15 and An80_92, respectively).

There is, however, a great variety of mafic clast types present

in these meteorites. This variability is not as well documented

as the typical eucritic meteorites. Numerous studies have

recognized, however, that these clasts represent an additional

important suite of mafic rocks from the basaltic achondrite

parent body (Bunch, 1976; Delaney et al., 1981; Dymek et al.,

1976; Simon and Papike, 1983; Treiman and Drake, 1984).

These clasts extend the compositional ranges for the major

minerals beyond the limited range of clasts in the eucrites, and

provide greater insight into the nature of the solid-liquid

fractionation on the basaltic achondrite parent body than is

available by studying the eucrites alone.

Prior to the discovery of polymict achondrite breccias in

Antarctica, the non-Antarctic polymict breccias were generally

referred to as howardites, and all the non-Antarctic examples

contain clasts of both orthopyroxenitic and mafic material.

Some of the first polymict achondrites found at both Yamato

Mountains and Allan Hills in Antarctica differ from those

previously known, however, as they contain a variety of mafic,

or eucritic, clast types but no orthopyroxenite component

(Miyamoto et al., 1978; Takeda et al., 1978; Olsen et al.,

1978). For this reason, they were called polymict eucritic

breccias or, more commonly, polymict eucrites. Further study

revealed rare orthopyroxene grains in some of the Yamato

samples, and when the first Elephant Moraine samples were

studied a small orthopyroxenite component was recognized in

EET79005 and 79006 (Simon and Papike, 1983; Delaney et

al., 1982). As more Antarctic samples become available, it is

clear that these polymict basaltic achondrites have continuously variable amounts of the two main components. The

most orthopyroxene-rich meteorite appears to be Yamato 7308

(with 76% vol. opx.) and the most mafic clast-rich meteorite

is the Allan Hills I meteorite represented by ALHA 76005,

77302, 78040, and numerous other specimens. This Allan Hills

meteorite contains no orthopyroxenite component. Delaney,

Takeda, and Prinz (1983a) suggest that those meteorites

containing more than 90% (vol.) of eucritic, or mafic, material

be called polymict eucrites and those with less than 90% be

called howardites. Mason (1983b) suggests, alternatively, that

meteorites containing any orthopyroxenite component should

be called howardites.

As a group, the non-Antarctic polymict achondrites all

contain an orthopyroxenite component and most have more

than 10% (vol). The Victoria Land polymict achondrites, in

contrast, contain either no orthopyroxene or less than 10%

(vol.). Polymict achondrites with abundant orthopyroxene are,

however, found in Antarctica at Yamato Mountains, especially
68 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

in the 1979 collections (Takeda et al., 1984; Delaney, Prinz,

et al., 1984). Indeed, the Victoria Land and Yamato collections

together sample a greater variety of polymict basaltic

achondrites than do the non-Antarctic collection.

A number of clast types in the Antarctic samples has been

described by Delaney, O'Neil, et al. (1984). All of these clast

types have been recognized in both non-Antarctic howardites

and polymict eucrites. At present, no clast type is known that

occurs only in meteorites from one part of the world. The

Victoria Land, Yamato, and non-Antarctic polymict basaltic

achondrites are, therefore, believed to be a part of a continuum

of breccias that sample a significant part of the regolith of their

parent body or bodies.

NEW SAMPLES.—Samples of all the basaltic achondrite types

are represented in the Victoria Land collections but the

polymict eucrites are by far the most abundant. In the 1983

season, 13 basaltic achondrites were collected at the Elephant

Moraine meteorite deposit. Two diogenites (EET83246;

83247), one eucrite (83236), and 10 polymict basaltic

achondrites were collected (Table 8-1). Preliminary descriptions of these samples are given in Antarctic Meteorite

Newsletter, 8(1), 1985.

Diogenites

The two new Elephant Moraine diogenites increased the

number of Victoria Land samples to five (Table 8-3). This is

a small number of samples compared with the 35, or more,

diogenite samples recovered at Yamato Mountains (Takeda et

al., 1981). Because the total number of meteorites represented

both at Yamato Mountains and Victoria Land is either four or

five, there is a similar number of meteorites available from

each site. Unlike the Yamato diogenites, however, the Victoria

Land samples are similar to most non-Antarctic diogenites as

they are brecciated orthopyroxenites dominated by En70.75

pyroxene.

Eucrites

The eucrite EET 83236 is the eighth recovered from Victoria

Land and Thiel Mountains localities. It is a typical eucrite

containing lithic fragments with ophitic to radiate textures. It

is mineralogically similar to the other Antarctic and the

non-Antarctic eucrites (Tables 8-3 and 8-4, Figure 8-1, cf.

Delaney, Takeda, and Prinz, 1984).

The Victoria Land eucrites appear to represent eight different

meteorite falls as all have distinctive textures or mineral

compositions, or are separated by long distances from similar

meteorites. The eucrites, therefore, differ significantly from the

polymict achondrites as they are not found as groups of

samples at a single locality. Each of the Antarctic eucrites has

uniform Fe/(Fe+Mg) in its pyroxene and thus has been

thermally processed in the same way as most non-Antarctic

eucrites. Allan Hills 81011 is unique as it appears to be a

genomict breccia (Mason, 1983a). Treiman (1984) describes

81011 as a polymict eucrite having equilibrated basaltic clasts

in a vesicular glass matrix, and as representing a major impact

on the parent body. Allan Hills 81313, which contains

maskelynite and was described as a shergottite, is also

significantly different. Other eucrites (e.g. Padvarninkai;

Reckling Peak 80204) contain variable amounts of maskelynite

and, because mineral compositions in ALH81313 are identical

to those in typical eucrites and quite different from any

shergottite, it is suggested that this sample be classified as an

eucrite.

Allan Hills 81001 was classified as an anomalous eucrite

as it differs from most eucrites in several ways (Mason, 1983a).

This sample closely resembles the fine-grained eucritic clasts

typically found in Allan Hills polymict eucrites. It may be a

large clast that separated from the Allan Hills I polymict eucrite

shower during atmospheric descent and landed on the Antarctic

ice as a separate object (Delaney, 1984). Whether this sample

should be treated as a separate meteorite fall or grouped with

the Allan Hills I polymict eucrite is not clear. Both approaches

to classifying this sample have disadvantages. Perhaps further

study can demonstrate that Allan Hills 81001 should be treated

as a unique meteorite, but we assume here that it is a member

of the Allan Hills polymict eucrites.

There are eight Victoria Land eucrites, represented by eight

samples. In contrast, there are four to six Victoria Land

polymict eucrites represented by at least 32 samples. Similar

sample/meteorite ratios are calculated for the Yamato achondrites. Delaney (1984) has suggested that the eucrites were

strong meteorites that are represented by individual falls

whereas the polymict eucrites were friable and fell as showers.

Statistics for known eucrite falls support this suggestion as

showers are uncommon among the known eucritic falls.

Polymict Achondrites

Polymict basaltic achondrites are the most abundant Victoria

Land achondrites. Of the 40 or more samples known, 16 are

from Allan Hills and 16 from Elephant Moraine (Table 8-3).

The Allan Hills and Elephant Moraine suites together appear

to represent four or five meteorites that have been called Allan

Hills I, Allan Hills II, Elephant Moraine I, and Elephant

Moraine II by Delaney, O'Neil, et al. (1984). The samples

collected at Elephant Moraine during the 1983 field season

represent both Elephant Moraine I and II meteorites on the

basis of their textures and mineral composition. Feldspar Na/)

contents and pyroxene compositions, generated by electron

microprobe modal analysis, for the Elephant Moraine 1983

series are given in Figures 8-2 and 8-3. These data were

generated under the same conditions as the data presented by

Delaney, O'Neil, et al. (1984) for all the polymict eucrite suites

previously identified and may be compared directly with those

results (Figures 8-4 and 8-5).

Most polymict eucrites have pyroxene and feldspar of
NUMBER 28 69

TABLE 8-4.—Modes of Victoria Land 83-series achondrites (A = aubrite, alab = alabandite, D = diogenite, db =

daubreelite, E = eucrite, gyps = gypsum or anhydrite, nd = not detected, PA = polymict basaltic achondrite, tr = trace,

unrep = unrepresentative sample).

Number

83009 A

83015 A

83212 PA

83227 PA

83228 PA

83229 PA

83231 PA

83232 PA

83235 PA

83236 E

83237 PA

83246 D

83247 D

83251 PA

83283 PA

Number

83009 A

83015 A

83212 PA

83227 PA

83228 PA

83229 PA

83231 PA

83232 PA

83235 PA

83236 E

83237 PA

83246 D

83247 D

83251 PA

83283 PA

Oliv

0.4

2.96

0.3

nd

0.10

nd

nd

0.25

nd

nd

nd

0.43

nd

Kam

0.2

0.3

nd

nd

nd

nd

nd

nd

nd

Opx

99.0

95.1

15.2

19.2

19.7

13.1

26.8

24.6

24.6

98.2

98.7

22.6

22.7

Taen

nd

nd

nd

nd

nd

nd

Pig

0.2

0.4

43.8

28.5

33.3

33.7

16.1

14.2

12.0

0.63

nd

29.6

30.4

Others

db, alab

db, alab

unrep

gyps

Aug

nd

nd

4.7

6.2

7.3

8.3

11.8

12.8

14.0

0.21

nd

8.2

7.9

Feld

0.2

1.04

33.5

41.7

36.0

38.1

40.0

39.3

40.9

nd

0.1

34.3

35.5

Area (mm2)

92

103

48

107

91

117

118

136

150

86.7

SiO2

nd

nd

2.0

3.7

3.0

4.9

4.0

6.6

7.4

0.8

1.0

3.2

2.9

Em

nd

nd

0.17

0.31

0.57

1.3

1.1

1.05

0.69

nd

nd

0.37

0.24

Chr

nd

nd

0.26

0.50

0.05

0.30

0.05

tr

0.05

0.21

0.2

0.11

0.06

Phos

nd

nd

nd

0.05

0.05

nd

0.11

nd

0.05

nd

nd

0.05

nd

Trail

tr

tr

tr

0.3

tr

0.4

0.27

nd

nd

nd

EET 83236

= 276

FIGURE 8-1.—Modal distribution of pyroxene composition in the eucrite

EET83236, shown in a standard pyroxene quadrilateral. Dotted contour

includes 95% of modal analyses; solid line includes 50% of analyses.
70 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

83236

n = 312

83231

n = 220 83251

n= 165

83232

n = 189

J] 83283

n = 185

0.4 1.0 1.6 2.2 2.8

%Na2O

0.4 1.0 1.6 2.2 2.8 3.4

%Na2O

FIGURE 8-2.—Modal distribution of Na2O in basaltic achondrite feldspar. Data

are generated by a rapid electron microprobe modal technique and are of low

precision. Area of each histogram totals 100%.

variable composition (Delaney, O'Neil, et al., 1984). The

feldspar usually varies between An80 and An95 with most

having compositions near An90 (Na p -1.0-1.2% wt.). The

pattern of feldspar composition distribution can be used to

distinguish between the more sodic Yamato and the more calcic

Victoria Land polymict eucrites (Delaney, O'Neil, et al., 1984),

but among the Victoria Land suites only Allan Hills I and Allan

Hills II may be distinguished on the basis of feldspar

composition alone (Figure 8-5). The two Elephant Moraine

groups recognized by Delaney, O'Neil, et al. (1984) have

indistinguishable feldspar distributions (Figures 8-2 and 8-5).

The pyroxene distributions in these meteorites are distinct,

however, and are used to assign the samples to the appropriate

suites.

Delaney, O'Neil, et al. (1984) described pyroxene from the

Allan Hills I suite as dominated by homogeneous, eucritic

pyroxene (i.e., lying on tie lines, between orthopyroxene and

pigeonites (Ery^Wo^ ) and augites (~Wo4(M5) (Figure 8-4),

with compositions appropriate for equilibration at 800°-900°

C (Lindsley and Andersen, 1983). In addition, Allan Hills I

contains minor zoned pigeonite of the "Pasamonte-type"

(Takeda, 1979). Allan Hills II (78006) differs in having almost

no zoned pigeonite. Instead, it contains about 2%-4% of

homogeneous magnesian orthopyroxene (plus olivine), similar

to diogenitic pyroxene, and small amounts of pyroxene with

compositions between the eucritic and diogenitic ranges

(Figure 8-4).

The two Elephant Moraine suites have different pyroxene

distribution patterns (Figure 8-4). Elephant Moraine I is

dominated by compositionally homogeneous pyroxene

(En40_45) with minor amounts of the other pyroxene components described by Takeda (1979) and Delaney, O'Neil, et al.

(1984). This suite has a variety of pyroxene textural types in

its mineral and Iithic clasts. All but a few clasts appear to

contain homogenized (with respect to Fe and Mg) pyroxene

that reflects the influence of a late metamorphic overprint

(Delaney et al., 1982). The Elephant Moraine II suite has much

more variable pyroxene compositions. This suite has the

textural and compositional variability of the most abundant

non-Antarctic polymict achondrites, the howardites. All the

textural types described by Takeda (1979) and Delaney,

O'Neil, et al. (1984) occur in Elephant Moraine II, and the

entire pyroxene compositional range from En^WOj to

En20Wo40 is present. This suite differs from the howardites,

however, as it contains in excess of 90% of eucritic components

and only 2%-7% of diogenitic pyroxene. It, therefore, falls

within the modal composition range of polymict eucrites as

defined by Delaney, Takeda, and Prinz, 1983b, and Delaney,

Takeda, Prinz, et al., 1983.

The 10 new polymict achondrites from the 1983 Elephant

Moraine collections appear to fit into the two previously

described suites from this locality. Three samples have

distribution patterns for their pyroxene compositions that are

similar to Elephant Moraine I. The modal pyroxene data for

these samples are given in Figure 8-3. (EET83212 is omitted,

as the original thin section studied is dominated by a single

mafic clast and is, therefore, unrepresentative). The Elephant

Moraine I suite is dominated by pyroxene compositions

scattered about tie lines based at En4(M5 Wo ^ with a sparsely

populated tail toward more magnesian compositions (Figure

8-4) (Delaney, Takeda, and Prinz, 1984). This distribution is

seen in EET83235, 83237, and 83283 (Figure 8-3).

The modal compositions of many polymict eucrite samples

are given by Delaney, Takeda, and Prinz (1984) and modes of

the Elephant Moraine-83 series are given for comparison
NUMBER 28 71

EET 83228

N=32I

\ \ \ \ \ \\ EET 83237 \ \

N = 300

EET 83231

N=3I 3

) \

EET 83283 .'

N=379

FIGURE 8-3.—Modal distribution of pyroxene compositions in the 1983 Elephant Moraine polymict eucrites.

(Low precision data from automated modal program.) Contours as in Figure 8-1.

(Table 8-4). No major differences exist between the 83-series

samples and the previously described samples (Delaney,

Takeda, and Prinz, 1984). It is difficult to distinguish Elephant

Moraine I and II on the basis of the modal abundance of the

minerals alone (Table 8-4) although the distribution of

pyroxene compositions is distinct in the two suites (Figures

8-3 and 8-4). The new samples extend the modal ranges of the

two Elephant Moraine suites and confirm the indications that

modal heterogeneity exists within each suite as seen previously

within the Allan Hills I suite of polymict eucrites (Delaney,

Takeda, and Prinz, 1984).

On the scale of a thin section there are detectable modal

differences between different samples in all the Victoria Land

suites, but when the distribution of mineral compositions

within individual thin sections are compared, each suite has a

coherent signature from sample to sample. The data presented

for the Elephant Moraine 1983 samples, however, seem to

lessen the differences between Elephant Moraine I and II. All

of these samples may, therefore, be fragments of a single

heterogeneous meteorite, with variable degrees of metamorphism detectable in different samples rather than two distinct

meteorites, as previously suggested (Delaney et al., 1984c).
72 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 8-4.—Modal distribution of pyroxene compositions in suites of Antarctic polymict eucrites. Figure

includes three non-Antarctic polymict achondrites for comparison. Contours as in Figure 8-1.

In general, all the Victoria Land samples are heterogenous

when compared on the scale of a thin section (2.5 cm diameter),

but comparison of chemical analyses of larger samples (e.g.,

Reid and Le Roex, 1984) may indicate that they are chemically

uniform at the "hand sample" scale.

Because the polymict basaltic achondrites sample a continuum of breccias made up of several lithic components, the

assignment of a rigidly constrained rock name is difficult. Two

names are presently in common use: polymict eucrite and

howardite. No consensus presently exists with regard to the

usage of these terms, but polymict eucrites are dominated by

clasts of various eucritic components while howardites contain

additional pyroxenitic (or diogenitic) components. Using the

nomenclature scheme of Delaney, Takeda, Prinz, et al. (1983)

all the Elephant Moraine 83-series samples are "polymict

eucrites." Using the Mason (1983b) scheme, the samples of

Elephant Moraine II are "howarditic." Similar ambiguities

(caused by the different nomenclature schemes) occur when

the various nomenclatures are applied to other Victoria Land,

Yamato, and non-Antarctic polymict basaltic achondrites.

Comparison of the Victoria Land polymict achondrites with

the Yamato Mountains collection and the non-Antarctic

specimens reveals several differences from suite to suite. All

three collections of meteorites contain polymict achondrites

containing a variety of clast rock types. In both of the major

Antarctic collections (Yamato Mountains and Victoria Land)

the vast majority of lithic clasts may be descibed as eucritic.

Pyroxenitic material is rare or uncommon. The non-Antarctic

collection, on the other hand, contains many meteorites with a

large proportion of pyroxenitic clasts (10%-50% of the
NUMBER 28 73

original meteorite) while those dominated by eucritic material

are less common. Only about 25% of all non-Antarctic

polymict basaltic achondrites are dominated by eucritic clasts

(i.e., contain more than 90% of eucritic material). The most

characteristic lithic clast type in the Antarctic meteorites is

unequilibrated eucritic, described by Takeda et al. (1978) as

"Pasamonte-type." These clasts, which are usually less than 1

cm in diameter, are found in all the Antarctic suites but are not

as common in the non-Antarctic collections. The non-Antarctic

polymict breccias generally have not been characterized as

well as the Antarctic samples. Small lithic clasts of unequilibrated eucritic material have been recognized in many

non-Antarctic polymict achondrites but they do not appear to

be as abundant or as large as in the Antarctic collections.

Ureilites

Two new ureilites (ALH83014 and EET83225) were

collected in the 1983 field season. There are now 10 ureilites

from Victoria Land (with a total mass of 7.6 kg). Modes of

nine Victoria Land samples are given in Table 8-5 along with

the mean mode and standard deviation of the non-Antarctic

ureilites described by Berkley et al. (1980). The range of modal

composition in the Victoria Land ureilites is essentially

identical to that of non-Antarctic ureilites. EET83225 is one

of the most pyroxene-rich, having similar olivine/pyroxene

ratios to Dingo Pup Donga and the paired ureilite samples

ALHA82106 and 82130. ALH83014 is a ureilite having a

generally unshocked texture with euhedral to subhedral

graphite crystals present in veins between the silicates (Figure

8-6). Texturally and modally (Table 8-5) ALH83014 is similar

to ALHA78019. It has less metal + sulfide + graphite, however,

and the cores of silicate mineral grains are more magnesian

than in 78019. ALH83014 may be the second relatively

unshocked ureilite found with euhedral graphite blades but

pairing with ALH78019 may be demonstrated by further work.

Detailed chemical and petrographic study of these two samples

should provide useful constraints on the origin of the intensely

shocked ureilites. Olivine cores in 83014 are generally Fo81_83

with forsterite rims (Fo90_98) while pigeonite cores are

En76-78W°8-9-

EET83225 has a well-developed preferred orientation of its

olivine and pigeonite grains with carbonaceous material,

including diamond, limited to the grain boundaries. Unlike

other pyroxene-rich ureilites (e.g., ALHA82106 and 82130)

EET83225 does not contain any augitic pyroxene. None of the

Victoria Land ureilites resembles the augitic ureilite Yamato

74130 described by Takeda et al. (1979). Some of the Victoria

Land ureilites contain only pigeonitic pyroxene whereas others

have more variable pyroxene compositions indicating that

some exsolution'and possibly some inversion to orthopyroxene

occurred. (Note that the assignment of pyroxene "polymorphs"

in Table 8-4 is based only on composition and does not imply

that three polymorphs have been identified crystallographically. Indeed some of the "pigeonite" identified by this

program may represent analyses of overlapping orthopyroxene

and augite. See Delaney, O'Neil, et al. (1984) for more detail

of methods applied.)

Compositional variation of the olivine in the Victoria Land

ureilites is summarized in Figure 8-7. These data are of low

precision as they are generated by electron microprobe modal

analysis but they are consistent with published analyses and

provide an unbiased estimate of the modal olivine compositional range. Only two of the analyzed ureilites have the same

olivine distribution pattern (ALHA82106, 82130) suggesting

that these are the only paired samples in this group (Mason,

1984). Study of the distribution of pyroxene compositions is

in progress. Ureilites generally have olivine in the Fo80 to Fo90

range with a few more magnesian compositions present. These

patterns reflect the variable reduction of iron-bearing olivine

to forsterite plus metal that is typical of these meteorites.

Reckling Peak 80239 has a distinctive bimodal distribution

with about 25% of its olivine analyses more magnesian than

Fo95. This distribution suggests that evidence of reduction

reactions is particularly well preserved in this sample. The

paired samples, Allan Hills 82106 and 82130, have more

magnesian olivine but it is not clear if these compositions were

formed by the late redox processes that are typical of ureilites

rather than early magmatic reduction processes. The high

augite content of these samples (Table 8-4) is, however,

consistent with their position on the reverse fractionation trend

described by Goodrich and Berkley (1985). They defined

Fe-depletion in later formed silicates as a result of reduction

by magmatic graphite.

Subhedral-euhedral graphite grains have been described in

only two ureilites (ALHA78019 and ALH83014) although all

ureilites have interstitial graphite, often containing diamond

or lonsdaleite (Berkley and Jones, 1982). The presence of

euhedral graphite grains in ALHA78019 has been interpreted

as representing crystallization of magmatic carbon. Similarly

the presence of round inclusions in olivine, containing

kamacite, troilite, and cohenite (Fe3C), in at least four Victoria

Land ureilites (ALHA78019, 77257, 78262, and RKPA 82506)

is also believed to support crystallization from a carbon

saturated silicate melt (Berkley and Goodrich, 1985). Study

of these and other minor phases in ureilites (e.g. Berkley and

Goodrich, 1985; Goodrich and Berkley, 1985) should provide

useful insight into these meteorites.

Aubrites

The one aubrite found between 1976 and 1982, Allan Hills

78113, is a polymict breccia showing similarities to Cumberland Falls and containing chondritic inclusions that have been

described as F-chondritic (Verkouteren and Lipschutz, 1983),

as unequilibrated enstatite chondrites (Prinz et al., 1984), and

as reduced LL chondrites (Kallemeyn and Wasson, 1985). The
74 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

a)

b)

c)

d)

0.4 1.2

Allan Hills I

76005

N = I38

78040,61

N=259

81006,19

N = 2I5

81007,6

N = IO3

81009,17

N=I73

f) —'

Allan Hills

81010,8

N = 2I8

I

g)

h)

i)

2.0

Na2 0%

2.8 3.6

81012,5

N = 263

Allan Hills l

78006,10

N=253

Bialystok

AMNH 4007

NMNH 382

N=426

Macibini

4560-1

= 357

FIGURE 8-5.—Modal distribution of feldspar composition in suites of Antarctic polymict eucrites. Area of

histogram is 100%. (Scale bars are the same for all figures, with the left margin at 0.4 in all cases.)

aubritic host was described by Score et al. (1982) and Watters

and Prinz (1979). Volatile trace elements were analyzed by

Biswas et al. (1981) and Verkouteren and Lipschutz (1983).

The mineralogy of the ALHA 78113 host is typical of aubrites.

Two new aubritic samples from Allan Hills were identified

in the 1983 collection. These samples (ALHA83009 and

83015) are quite similar to each other but appear to be distinct

fromALHA78113.
NUMBER 28 75

k)

Elephant Moraine

79004,32

N=II9

Yamato

74I59.7IA

N=IO6

79005,37

N=I46

r)

m) 82600,10

790020,81 FC

= 85

N=I65

n)

Jodzie

FMNH 1371

t)

N = 23I

791186,81-3

N=2I4

0) Petersburg

2251-1

U)

N=I23

791960,91-

N=295

FIGURE 8-5.—Continued.

0.4 1.2

Na2O

2.0

Vo

2.8

Summary

The Victoria Land achondrites have provided impetus to

research on achondritic meteorites in general, by providing

sufficient samples of uncommon meteorite types that detailed

study is now easier. Initially, many Antarctic achondrites

appeared to be different from the non-Antarctic collections

but, as more research is published and more Antarctic

meteorites are found, it is clear that the Antarctic and

non-Antarctic collections are sampling similar populations of

meteorites.

The basaltic achondrite samples increase the known

diversity of these meteorites. These meteorites contain clasts

of many rock types ranging from magnesian orthopyroxenites

(En^gsWO}) with minor olivine (as magnesian as Fo90) to very

iron rich mafic clasts dominated by En30Wo15_30 pigeonites and
76 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 8-5.—Modes of Victoria Land ureilites (nd = not detected, tr = trace. Non-Antarctic data from Berkley

et al., 1980.)

Number

83225

83014

82506

82130

82106

81101

80239

78019

77257

Oliv

52.1

85.2

67.1

46.1

47.9

58.9

59.0

76.0

81.5

Non-Antarctic ureilites:

Mean

S.D.

65.9

10.4

Opx

2.9

1.5

3.6

29.2

31.8

17.1

7.1

4.6

7.6

Pig

40.8

11.3

24.3

11.9

8.9

13.8

29.0

8.8

5.8

31.9

10.6

Aug

nd

nd

nd

7.6

6.4

0.24

nd

0.3

0.1

Feld

nd

nd

nd

nd

0.1?

nd

tr?

nd

0.1?

-

-

SiO2

0.1

0.1

0.5

nd

nd

0.5

nd

nd

nd

0.1

-

Sulf Metal Other

Combined

4.1

1.9

4.5

5.1

5.0

8.9

4.9

10.6

4.9

0.9 1.2

0.6 1.1

Area

mm2

60

64

180

154

109

162

74

54

36

-

-

Number

points

725

879

641

860

990

847

888

828

717

-

-

P.t.s

LIB

,25

,10

, 6

,11

,6

,15

,42

-

-

'Catalogue number of polished thin section examined in this study; LIB = Library section.

FIGURE 8-6.—Euhedral to subhedral graphite crystals in ALH83014: a,

transmitted light; b, reflected light. Long dimension of photographs is ~2 mm.

augites. The chsts described in numerous studies document

continuous trends of Fe/Mg increase with increasing modal

abundance of pigeonite, augite, feldspar, and silica. These

trends appear to reflect general trends of solid-liquid fractionation on the basaltic achondrite parent body that are independent

of the present state of brecciation and mixing of the known

samples. Metamorphism is known to have modified the

compositions of lithic clasts in many polymict samples from

Victoria Land and in most eucrites, but no systematic studies

have yet tried to distinguish between unmodified igneous clasts

and metamorphosed clasts. Detailed study of the original trends

of igneous fractionation from clast to clast requires that

metamorphosed clasts be eliminated from this type of study.

Similarly, impact-melt clasts in these meteorites have received

little attention and definitive tests to distinguish between

impact-generated clasts and original igneous clasts are not

available. The small samples of the polymict basaltic

achondrites in the non-Antarctic collections were generally

insufficient for these types of studies to be completed, but the

large number of Victoria Land samples presently available

makes more complete and detailed study possible. In particular,

the identification of large unbrecciated lithic clasts in these

breccias is of great importance for the study of rock types that

differ from the typical eucrites and diogenites.

The Antarctic ureilite collections have more than doubled

the number of samples available and have provided examples

of previously unknown types that constrain models of ureilite

origin more closely. In general, the popular model of a cumulus

origin (Berkley et al., 1980) is supported by evidence from the

Victoria Land samples, but controversy about the relationships

between the silicate and carbonaceous fractions continues.

The Antarctic aubrites do not differ greatly from the

non-Antarctic collection but study of the dark inclusions in

these meteorites is revealing chondritic material unlike the

previously known chondrite groups. Further study should

distinguish between the competing hypotheses that these
NUMBER 28 77

30

20

10

0

70 r

50

30

10

0

L

20

10

0

50r

4 0

30

20

10

0L

EET

83225

N

S

434

N=338

ALHA

81101

N=426

70

ALHA

78019,15

70 80 90 100

ALHA

82130

80 90 100

80 90 100

70 80 90 100

PCA

82506,25

80 90 100

ALHA

82106,6

N=436

80 90 100

RKPA

80239,6

VJl

20

10

ALHA

77257,42

N=262

70 80 90 100

FIGURE 8-7.—Modal distribution of olivine compositions (mole % forsterite) in Victoria Land ureilites. Data

are of low precision but provide a consistent criterion of comparison for these meteorites. Area of histogram is

100%.
78 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

inclusions represent a new type of chondrite, or that they are

actually inclusions of ordinary chondritic material that was

subjected to metamorphism and metasomatism after incorporation in an aubritic host.

The discovery of unusual material in the Antarctic

achondrites is prompting increasing study of non-Antarctic

collections with the result that previously unrecognized

material is being identified. With the assured supply of

carefully sampled achondrites from Antarctica, the next

decades of research on achondritic meteorites should prove

very rewarding and fruitful.

Literature Cited

Berkley, J.L., and C.A. Goodrich

1985. Cohenite-bearing Metallic Spherules in Ureilites: Petrology and

Implications. In Lunar and Planetary Sciences XVI, pages 49—50.

Houston: Lunar and Planetary Institute.

Berkley, J.L., and J.H. Jones

1982. Primary Igneous Carbon in Ureilites: Petrological Implications.

Journal of Geophysical Research, 87(supplement):A353-A364.

Berkley, J.L., GJ. Taylor, K. Keil, G.E. Harlow, and M. Prinz

1980. The Nature and Origin of Ureilites. Geochimica et Cosmochimica

Ada, 44:1579-1597.

Biswas, S., T.M. Walsh, H.T. Ngo, and M.E. Lipschutz

1981. Trace Elements of Selected Antartic Meteorites—II: Comparison

with Non-Antarctic Specimens. Memoirs of the National Institute

of Polar Research (Japan), special issue, 20:221-228.

Bunch, T.E.

1976. Petrography and Petrology of Basaltic Achondrite Polymict Breccias

(Howardites). In Proceedings of the Sixth Lunar and Planetary

Science Conference, pages 469-492.

Delaney, J.S.

1984. Why Did So Many Polymict Eucrites Land and Survive Only in

Antarctica? In Lunar and Planetary Science XV, pages 206-207.

Houston: Lunar and Planetary Institute.

Delaney, J.S., C. O'Neil, C.E. Nehru, M. Prinz, C. Stokes, H. Kojima, and K.

Yanai

1984. The Classification and Reconnaissance Petrography of Basaltic

Achondrites from the Yamato 1979 Collection Including Pigeonite

Cumulate Eucrites, a New Group. Memoirs of the National Institute

of Polar Research (Japan), special issue, 35:53-80.

Delaney, J.S., M. Prinz, C.E. Nehru, and G.E. Harlow

1981. A New Basalt Group from Howardites: Mineral Chemistry and

Relationships with Basaltic Achondrites. In Lunar and Planetary

Science XII, pages 211-213. Houston: Lunar and Planetary Institute.

Delaney, J.S., M. Prinz, C.E. Nehru, and C. O'Neil

1982. The Polymict Eucrites Elephant Moraine A79004 and A79011 and

the Regolith History of a Basaltic Achondrite Parent Body. In

Journal of Geophysical Research, supplement, 87:A339—A352.

Delaney, J.S., M. Prinz, C.E. Nehru, and C.P. Stokes

1984. Allan Hills A81001, Cumulate Eucrites and Black Clasts from

Polymict Eucrites. In Lunar and Planetary Science XV, pages

212-213. Houston: Lunar and Planetary Institute.

Delaney, J.S., H. Takeda, and M. Prinz

1983a. Modal Comparison of Yamato and Allan Hills Polymict Eucrites.

Memoirs of the National Institute of Polar Research (Japan), special

issue, 30:226-233.

1983b. Reply to B. Mason: "Definition of a Howardite." Meteoritics,

18:247-248.

1984. The Polymict Eucrites. Journal of Geophysical Research, supplement, 89:C251-C288.

Delaney, J.S., H. Takeda, M. Prinz, C.E. Nehru, and G.E. Harlow

1983. The Nomenclature of Polymict Basaltic Achondrites. Meteoritics,

18:103-111.

Dymek, R.F., A.L. Albee, A.A. Chodos, and GJ. Wasserburg

1976. Petrography of Isotopically-dated Clasts in the Kapoeta Howardite

and Petrologic Constraints on the Evolution of Its Parent Body.

Geochimica et Cosmochimica Acta, 40:1115-1130.

Fukuoka, T.

1984. Comparison of Chemical Compositions of Yamato Polymict

Eucrites. Meteoritics, 19:227.

Goodrich, C.A., and J.L. Berkley

1985. Minor Elements in Ureilites: Evidence for Reverse Fractionation

and Interstitial Silicate Liquid. In Lunar and Planetary Science

XVI, pages 280-281. Houston: Lunar and Planetary Institute.

Hey, M.H.

1966. Catalogue of Meteorites, lxviii + 637 pages. London: British

Museum (Natural History).

Hutchison, R., A.W.R. Bevan, and J.M. Hall

1977. Appendix to the Catalogue of Meteorites, xxvii + 297 pages.

London: British Museum (Natural History).

Kallemeyn, G.W., and J.T. Wasson

1985. The Compositional Classification of Chondrites: IV Ungrouped

Chondritic Meteorites and Clasts. Geochimica et Cosmochimica

Acta, 49:261-270.

Lindsley, D.H., and D.J. Andersen

1983. A Two-Pyroxene Thermometer. Journal of Geophysical Research,

supplement, 88:A887-A907.

Marvin, U.B.

1984. Meteorite Distributions on the Main Icefield of the Allan Hills

Region, Antarctica. Meteoritics, 19:265-266.

Mason, B.

1983a. [Description.] Antarctica Meteorite Newsletter, 6:7.

1983b. Definition of a Howardite. Meteoritics, 18:245.

1984. [Description.] Antarctic Meteoritic Newsletter, 7:10.

Miyamoto, M., H. Takeda, and K. Yanai

1978. Yamato Achondrite Polymict Breccias. Memoirs of the National

Institute of Research (Japan), special issue, 8:185-197.

Olsen, E.J., A. Noonan, K. Fredriksson, E. Jarosewich, and G. Moreland

1978. Eleven New Meteorites from Antarctica, 1976-1977. Meteoritics,

13:209-225.

Prinz, M., C.E. Nehru, M.K. Weisberg, and J.S. Delaney

1984. Type 3 Enstatite Chondrites: A Newly Recognized Group of

Unequilibrated Enstatite Chondrites (UEC's). In Lunar and

Planetary Science XV, pages 653-654. Houston: Lunar and

Planetary Institute.

Reid, A.M., and A.P. Le Roex

1984. Compositions of 7 Allan Hills Polymict Eucrites and One Diogenite.

Meteoritics, 19:299.

Schultz, L., and M. Freundel

1984. Terrestrial Ages of Antarctic Meteorites. Meteoritics, 19:310.

Score, R., T.V.V. King, CM. Schwarz, A.M. Reid, and B. Mason

1982. Descriptions of Stony Meteorites. In U.B. Marvin and B. Mason,

editors, Catalogue of Meteorites from Victoria Land, Antarctica,

1978-1980. Smithsonian Contributions to the Earth Sciences,

24:19-48.

Scott, E.R.D.

1984. Pairing of Meteorites Found in Victoria Land, Antarctica. Memoirs

of the National Institute of Polar Research (Japan), special issue,

35:102-125.

Simon, S.B., and JJ. Papike

1983. Petrology of Igneous Lithic Clasts from Polymict Eucrites ALHA

76005 and ALHA 77302. Meteoritics, 18:35-50.

Takeda, H.

1979. A Layered Crust Model of a Howardite Parent Body. Icarus,
NUMBER 28 79

40:445-470.

Takeda, H., M.B. Duke, T. Ishii, H. Haramura, and K. Yanai

1979. Some Unique Meteorites Found in Antarctica and Their Relation

to Asteroids. Memoirs of the National Institute of Polar Research

(Japan), special issue, 15:54—76.

Takeda, H., M. Miyamoto, K. Yanai, and H. Haramura

1978. A Preliminary Examination of the Yamato-74 Achondrites. Memoirs

of the National Institute of Polar Research (Japan), special issue,

8:170-184.

Takeda, H. and H. Mori

1984. The Diogenite-Eucrite Links and the Crystallization History of a

Crust of Their Parent Body. Journal of Geophysical Research,

supplement, 90:C636-C648.

Takeda, H., H. Mori, and K. Yanai

1981. Mineralogy of the Yamato Diogenites As Possible Pieces of a Single

Fall. Memoirs of the National Institute of Polar Research (Japan),

special issue, 20:81-99.

Treiman, A.H.

1984. Polymict Eucrite ALHA 81011: Equilibrated Clasts in a Glassy

Matrix. Meteoritics, 19:323-324.

Treiman, A.H., and M.J. Drake

1984. Basaltic Volcanism on the Eucrite Parent Body: Petrology and Phase

Equilibria of ALHA 80102 and the Discovery of Ferroan Troctolite.

In Lunar and Planetary Science XV, pages 862-863. Houston: Lunar

and Planetary Institute.

Verkouteren, R.M., and M.E. Lipschutz

1983. Cumberland Falls Achondritic Inclusions—II: Trace Elements of

Forsterite Chondrites and Meteorites of Similar Redox State.

Geochimica et Cosmochimica Acta, 47:1625-1633.

Watters, T.R., and M. Prinz

1979. Aubrites: Their Origins and Relationship to Enstatite Chondrites.

In Proceedings of the Tenth Lunar and Planetary Science

Conference, pages 1073-1093.

Weber, H.W. O. Braun, L. Schultz, and F. Begemann

1982. The Noble Gases in Antarctic and Other Meteorites. Zeitschritt fur

Naturforsch, 38A:267-272.
9. Antarctic Carbonaceous Chondrites: New Opportunities

for Research

Harry Y. McSween, Jr.

Introduction

Milestones in the understanding of carbonaceous chondrites

reached previously can be traced in a series of reviews on the

subject (Mason, 1963; Hayes, 1967; Mason, 1971; Nagy, 1975;

McSween, 1979a). One might logically expect that this paper

on Antarctic carbonaceous chondrites, most of which have

been found since the last review article was published, should

provide an updated account of new discoveries and insights.

This, unfortunately, is not true, because this subset of

carbonaceous chondrites has not yet been thoroughly studied.

The Antarctic meteorite bonanza is just too vast to be

assimilated quickly, and other classes of meteorites (especially

the achondrites) - have received more attention. Those major

contributions that have been made during the last few years are

derived mainly from studies of non-Antarctic carbonaceous

chondrites.

The intent of this paper is to describe what kinds of

carbonaceous meteorites are available in the Antarctic collections of the United States and Japan, and to summarize briefly

what research has been done. Some new data that bear on the

question of pairings among Antarctic carbonaceous chondrites

will also be presented. The importance of this paper really lies

in what it does not say—the still available research opportunities that these meteorites offer.

Classification of Carbonaceous Chondrites

The classification used for carbonaceous chondrites is

somewhat unwieldy and has evolved in a number of steps. Van

Schmus and Wood (1967) distinguished Cl, C2, and C3

chondrites based on petrographic and chemical characteristics.

This sequence supposedly reflected a sort of decreasing

"primitiveness," distinct from the grade of thermal metamorphism described by petrologic types 4 to 6. Van Schmus and

Hayes (1974) recognized two groups of C3 chondrites, which

they called the Ornans (now abbreviated CO3) and Vigarano

Harry Y. McSween, Jr., Department of Geological Sciences,

University of Tennessee, Knoxville, Tennessee 37996.

(CV3) subtypes. Wasson (1974) stressed that Cl, C2, and C3

chondrites were not an isochemical group and devised the

names Cl (Ivuna type, formerly Cl) and CM (Mighei type,

formerly C2) to parallel the classification of C3 chondrites into

CV and CO groups. McSween (1979a) accepted Wasson's

chemical distinctions and added another: CR (Renazzo group).

He also suggested a reinterpretation of petrologic types 3 to 1

to reflect increasing degrees of aqueous alteration. A few

carbonaceous chondrites have been thermally recrystallized

and are assigned to petrologic type 4.

In Table 9-1 are listed carbonaceous chondrites recognized

in the Antarctic collections of the Unites States (Victoria Land)

and Japan (Queen Maud Land) through 1984. Included are

classification, original weights, and the best descriptive

references for each. In many cases no descriptive references

are available, except in the original newsletter announcements,

which are not referenced here. Classifications are the generally

accepted assignments published in the newsletters of the

Antarctic Meteorite Working Group and the National Institute

of Polar Research. Recrystallized chondrites classified as C4

are difficult to assign to a specific group, even if adequate

chemical data are available.

Petrologic, Chemical, and Isotopic Studies of Antarctic

Carbonaceous Chondrites

CM2 CHONDRITES

Most of the work on CM chondrites has been done on

Yamato samples; the Allan Hills samples are almost untouched. Brief petrographic descriptions are available for

Y-74641, Y-74642, Y-74662 (Mason and Yanai, 1983),

Y-75293, Y-790123 (Dceda, 1983a), and Y-793321, Y-790003,

Y-791198, Y-791824, B-7904 (Kojimaetal., 1984). McSween

(1979b) also provided some petrographic data on ALHA77306,

and Steele et al. (1985) studied cathodoluminescence zoning

of olivines in B-7904. Although some petrographic differences

are apparent, these meteorites do not expand the limits of

primary petrographic variation already known from non81
82 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 9-1.—Antarctic carbonaceous chondrites. TABLE 9-1.—Continued.

Sample Classification

Meteorites from Victoria Land

ALHA77306

ALHA78261

ALHA81002

ALHA81004

ALHA81312

ALH82100

ALH82131

ALH83016

ALH831OO

ALH83102

EET83224

EET83226

EET83250

ALH84029

ALH84030

ALH84031

ALH84032

ALH84033

ALH84034

ALH84042

ALH84044

ALHA77003

ALHA77029

ALHA77307

ALH82101

RKPA 80241

ALHA81OO3

ALHA81258

ALHA84028

ALH82135

PCA82500

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

C03

C03

C03

C03

CV3

CV3

CV3

CV3

C4

C4

Weight (g)

19.9

5.1

14.0

4.7

0.7

24.3

1.0

4.1

434.6

1240.8

8.6

33.1

11.5

119.8

6.2

12.5

7.9

60.4

44.1

51.2

147.4

779.6

1.4

181.3

29.1

0.1

10.1

1.1

735.9

12.1

90.9

Best descriptive references

McSween (1979b)

Ikeda(1982)

McKinley and Keil (1984)

Nagahara and Kushiro

(1982)

Scott (1984)

Scott (1985)

Scott and Taylor (1985)

Sample Classifi cation

Meteorites from Queen Maud Lana

Y-74641

Y-74642

Y-74662

Y-75260

Y-75293

B-7904

Y-790003

Y-790032

Y-790112

Y-790123

Y-791198

Y-791824

Y-793331

Y-793332

Y-74135

Y-790992

Y-791717

Y-75260

Y-6903

Y-790112

Y-793495

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

CM2

C03

C03*

C03

CV3

CV4

CR2

CR2

* Y-790992 is listed only as a C3;

Weight (g)

I

4.5

10.6

151

4.0

8.1

1234

4.3

6.1

24.0

6.8

179.8

23.3

379.3

7.7

25,3332

4.0

150

24.0

45.0

Best descriptive references

Mason and Yanai (1983)

Mason and Yanai (1983)

Ikeda(1983a)

Ikeda (1983a)

Kojima et al. (1984)

Ikeda (1983)

Kojima et al. (1984)

Kojima et al. (1984)

Kojima et al. (1984)

Kojima et al. (1984)

Okada and Shima (1979);

Scott (1985)

, but I have assigned it to C03 based on

inspection of a thin section in the collection of the National Institute of Polar

Research. Ikeda

ALHA77003.

(1983a) also noted that this meteorite was similar to

Antarctic CM chondrites.

High-resolution electron microscope studies of the matrices

of ALHA77306 (McKee and Moore, 1980) Y-74662 (Akai,

1982), Y-793321, B-7904 (Akai, 1984) and Y-791198 (Akai

and Kanno, 1985) have been reported. These studies have

identified a bewildering variety of phyllosilicates with platy,

tubular, and poorly crystalline structures, much like those

found in non-Antarctic CM chondrites. Ikeda (1983a) reported

the chemical compositions of matrix phyllosilicates in

Y-790123, Y-75293, and Y-74662 to be similar to other

published analyses. Fujimura et al. (1982) documented

preferred orientations of phyllosilicates in Y-74642 and

Y-74662 by x-ray pole figure goniometry, indicating anisotropic deformation of these meteorites.

Bulk chemical data are available for Y-74642, Y-74662,

Y-790032, and Y-791198 (Haramura et al., 1983). Trace

element data for Y-74662 were determined by Knab and

Hintenberger (1978). Carbon and sulfur determinations have

been reported for Y-76442 and ALHA77306 (Gibson and

Yanai, 1979) and B-7904, Y-791824, Y-793321 (Gibson et

al., 1984). Carbon and nitrogen abundances in Y-791198 were

published by Shimoyana et al. (1985). Major element

concentrations, including sulfur, are near normal CM levels,

but depletions of carbon in some meteorites may reflect

exposure to liquid water in the Antarctic environment.

The apparent leaching of carbon in some CM chondrites is

a disturbing finding, especially for what it portends for studies

of organic compounds. ALHA77306 has significantly lower

amino acid concentrations than non-Antarctic CM chondrites

(Cronin et al., 1979), and Y-7891824, Y-793321, and B-7904

contain practically none of these compounds (Gibson et al.,

1984; Shimoyama and Harada, 1984). However, amino acids

in Y-74662 and Y-79118 are at higher concentrations

(Shimoyama et al., 1979, 1985). Aspartic acid, serine, glycine,

alanine, theonine, glutamic acid, valine, norvaline, and leucine

have been identified, as well as aromatic compounds from

pyrolysis experiments (Holzer and Oro, 1979; Murae et al.,

1983, 1984).
NUMBER 28 83

Stable light isotope (N, C, H) compositions reported for

Y-790003 and Y-790032 (Grady et al., 1983) indicate that

Y-790003 is highly unusual. It is characterized by enrichment

of heavy carbon and nitrogen, but not deuterium, and falls

outside the known ranges for CM chondrites. Isotopic

abundances of noble gases (He, Ne, Ar, Kr, Xe) in B-7904,

Y-74662, and Y-791198 are similar to other non-Antarctic

CM chondrites (Nagao et al., 1984; 1985); however, a new

component of Kr and Xe has been reported in B-7904. No data

are available on cosmogenic nuclides.

Magnetic studies of Y-74662 (Nagata, 1980; Brecher, 1980)

confirmed its CM2 classification. The magnetic properties of

ALHA77306 have been used to estimate its magnetite content

at less than 0.8 weight percent (Hyman and Rowe, 1979).

CR2 CHONDRITES

From inspection of thin sections in the collection at the

National Institute of Polar Research in 1982, the author

tentatively classified Y-790112 and Y-793495 as CR chondrites, as subsequently reported in the National Institute of

Polar Research special issue of 1982. Oxygen isotopic analysis

of Y-790112 (Clayton et al., 1984) has confirmed this

classification. A bulk chemical analysis of this meteorite was

given by Haramura et al. (1983). Light element stable isotope

analysis is also consistent with the CR assignment (Grady et

al., 1983), though data from Y-790112 indicate the CR group

is highly variable in its isotopic character. Nothing is known

about Y-793495. This is a particularly important pair of

meteorites, because so little is known about the CR group with

only two non-Antarctic members.

CO3 CHONDRITES

The two large CO chondrites in the Allan Hills collections

(ALHA77003 and 77307) have understandably received most

of the attention accorded to this group, although massive

Y-791717 offers an exciting opportunity. Petrographic descriptions of ALHA77003 (Ikeda, 1982), ALHA77307 (Nagahara

and Kushiro, 1982), and ALHA77029 (McKinley and Keil,

1984) have been published. The latter was found in a collection

of pebble-sized meteorites. Scott et al. (1981) and Scott (1984)

provided some additional petrographic data on all three

meteorites. ALHA77307 appears to be the least metamorphosed of the three chondrites. Brief petrographic descriptions

and studies of the alteration of Y-791717 and Y-74135 were

presented by Kojima et al. (1984).

Bulk chemical analyses have been performed for ALHA77003

(Rhodes and Fulton, 1980; Jarosewich, 1980; Kallemeyn and

Wasson, 1982a), ALHA77029 (Kallemeyn and Wasson,

1982a), ALHA77307 (Biswas et al., 1981; Kallemeyn and

Wasson, 1982a), and Y-791717 (Haramura et al., 1983). The

chemical composition of ALHA77307 has resulted in some

uncertainty about its classification. Biswas et al. (1981)

assigned this meteorite to the CV group, based on its high Cd

concentration, but Kallemeyn and Wasson (1982b) concluded

that its composition was similar in most respects to CO and

CM chondrites. They also suggested that weathering may have

been a factor in altering its composition. Its thermoluminescence properties are consistent with the CO classification,

although it is not a normal member of that group (Sears and

Ross, 1983). Petrographic data (Scott et al., 1981) also suggest

ALHA77307 is an unusual member of this class, although

Kainsaz, which it most resembles, is also unusual.

Organic constituents have been analyzed only in ALHA77307

(Moore et al., 1981; Murae et al., 1983). It contains only traces

of amino acids, and pyrolysis experiments indicate highly

volatile products.

Wieler et al. (1985) reported isotopic measurements of noble

gases in ALHA77307 and ALHA82101. The only cosmogenic

nuclide data available for these meteorites is for ALHA77003.

Nishiizumi (1984) summarized

 53Mn, 26A1, 36C1, and 14C

activities and calculated a cosmic ray exposure age of 20

million years.

CV3 CHONDRITES

Virtually nothing is known about any of these chondrites,

but most are very small, and representative samples may be

difficult to obtain. Scott (1984) briefly mentions RKPA80241.

C4 CHONDRITES

Petrographic descriptions of Y-6903 (Okada and Shima,

1979; Scott, 1985), PCA82500 (Scott et al., 1984), and

ALH82135 (Scott, 1985) indicate that these meteorites are

recrystallized and resemble Karoonda, though each is distinctive in some ways. The oxygen isotopic composition of Y-6903

is identical to that of Karoonda, and

 18O fractionation between

plagioclase and magnetite corresponds to an equilibration

temperature of 600° C (Clayton et al., 1979).

Bulk chemical analyses of Y-6903 and PCA82500 were

reported by Kallemeyn (1985). Y-6903 may be a metamorphosed CVF chondrite, but compositional data for PCA82500

suggest affinities with both the CO and CV groups, as already

noted for Karoonda (Kallemeyn and Wasson, 1982b). An

analysis for carbon and sulfur in Y-6903 was reported by

Gibson and Yanai (1979). Noble gas isotopic abundances for

ALH82135 and PCA82500 were determined by Wieler et al.

(1985).

Pairing of Antarctic Carbonaceous Chondrites

Very little information exists on which to make pairing

assignments for these meteorites. Of both Antarctic collections,

the only carbonaceous chondrite for which a terrestrial age has

been determined is ALHA77003. Its reported

 14C age is

35,600±500 years (Fireman, 1983), and its

 36C1 age is
84 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

110,000170,000 years (Nishiizumi, 1984). Four CM2 chondrites from the Allan Hills (77306, 78261, 81002, and 81004),

and two Allan Hills CO3 chondrites (77003, and 82101) have

been previously paired, based on petrographic similarities

(Antarctic Meteorite Working Group, 1984). However, marked

differences in olivine compositions (Scott et al., 1981) and

noble gas abundances (Wieler et al., 1985) between ALHA77003

and ALH82101 suggest that these specimens are not paired.

To assist in this thorny problem of pairing assignments,

provided below are partial modal analyses of the Victoria Land

CM and CO chondrites (except ALH84033), obtained using

optical point-counting methods outlined by McSween (1979b).

It must be noted that no accurate determination of modal

variability within any one meteorite has ever been made;

however, point counts by the author on two thin sections for

each of two different CO chondrites agreed within about 10

percent. An additional problem hampering accurate modal

analyses is brecciation. Both of these meteorite classes are now

known to contain clasts with different petrographic properties

(McSween, 1979b; Rubin et al., 1984), and these could

introduce substantial variations on a thin-section scale within

one meteorite. In order to minimize these effects, I have relied

only on matrix/chondrule ratios (rather than differences in the

relative proportions of inclusions, chondrules, monomineralic

fragments, etc.), where chondrules refer to everything that is

not fine-grained, opaque matrix. This gross parameter, when

combined with subjective assessment of degrees of hydrous

alteration in CMs, and oxidation or textural blurring due to

thermal metamorphism in COs, provides the basis for the

pairings suggested in Table 9-2.

Three possible groupings of CM chondrites are proposed.

The relatively unaltered chondrites are subdivided into two

groups from the Allan Hills and two unpaired samples from

Elephant Moraine based on matrix/chondrule ratios. However,

petrographic variability within a large CM chondrite might

permit these groupings to overlap. Microprobe defocused beam

analyses of matrix would certainly help define these two

groups. None of the altered CM chondrites from the Allan Hills

are paired because of large differences in matrix/chondrule

ratios. None of the Elephant Moraine specimens are paired for

the same reason. No modal data are presented for the large

group of highly altered CM chondrites from the Allan Hills,

but they are paired because of their exceptional petrography.

Chondrules and inclusions are so heavily altered that it is

difficult to distinguish these from matrix in many cases. This

alteration is so distinctive that these meteorites can probably

be paired with confidence.

No obvious pairings exist among CO3 chondrites. Based

on matrix/chondrule ratios, ALHA77129 and ALHA77307

could be paired, but differences in textural blurring, equilibration seen in olivine histograms (Scott et al., 1981), and bulk

compositions (Kallemeyn and Wasson, 1982a) preclude

pairing of any of these CO3 chondrites.

TABLE 9-2.—Pairing information.

Meteorite

CM2

j—ALHA81002

I ALHA810O4

1— ALH82100

1—ALHA78261

II ALH82131

1—ALH83016

ALHA77306

ALHA81312

EET83224

EET83226

EET83250

•—ALH831OO

III

ALH83102

ALH84029

ALH84030

ALH84031

ALH84032

ALH84034

ALH84042

— ALH84044

C03

ALHA77003

ALHA77029

ALHA77307

Matrix/Chondrule

volume ratio

3.70

2.78

3.33

2.27

low*

1.96

4.17

1.52

1.75

0.65

2.50

t

t

t

t

t

t

t

t

t

0.43

0.79

0.76

Subjective

observations

relatively unaltered

relatively unaltered

relatively unaltered

relatively unaltered

relatively unaltered

relatively unaltered

altered

altered

relatively unaltered

relatively unaltered

altered with clasts

highly altered

highly altered

highly altered

highly altered

highly altered

highly altered

highly altered

highly altered

highly altered

metamorphosed, reduced

metamorphosed, reduced

unmetamorphosed, oxidized

I, II, III Tentatively paired groups

•Sample too small for modal analysis

f Sample too highly altered for modal analysis

Conclusions

The Antarctic meteorite collections from Victoria Land and

Queen Maud Land contain all of the known classes of

carbonaceous chondrites except CI (Cl). These specimens

greatly enlarge the limited quantities of carbonaceous chondrites in museum collections. Moreover, available pairing

information, though limited, suggests that they represent many

different falls. Unfortunately, many of these meteorites are

small, and work has understandably focused on the larger

specimens. Studies of even large Antarctic carbonaceous

chondrites are very limited, however, and should be pursued

more vigorously.

ACKNOWLEDGMENTS.—This work was partly supported by

NASA grant NAG 9-58.

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86 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

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10. The Emerging Meteorite: Crystalline Structure

of the Enclosing Ice

Anthony J. Gow and William A. C as sidy

Introduction

While searching for meteorites in the Far Western Icefield

of the Allan Hills region during the austral summer of

1982-1983, Carl Thompson discovered a small, walnut-sized

meteorite with just its tip protruding above the ice surface

(Cassidy et al., 1983). Closer inspection showed that this

meteorite was not surrounded by a zone of clear ice as would

have been expected if melting and refreezing had occurred

around the stone. The meteorite appeared to be still embedded

in the original ice and becoming exposed for the first time at

the ablation surface. If this interpretation were proved correct,

this would be the first example observed in Antarctica of an

emerging stone, a discovery of special importance because the

terrestrial age of the meteorite would be the same as that of the

enclosing ice. Since the terrestrial age of the stone can be

determined by measurement of several different nuclides (e.g.,

26A1, 10Be, ^Cl, 81Kr, 58Mn, and 14C), such dating would

furnish, for the first time, a good measure of the time that has

elapsed since the meteorite embedded itself in the Antarctic ice

sheet. This, in turn, would provide an independent check on

age determination methods currently being developed for

dating ancient ice. Because of the potentially unique nature of

this meteorite it was left untouched and collected within a block

of ice measuring approximately 36 cm long by 30 cm wide and

10 to 20 cm deep. This sample was shipped frozen to the U.S.

Army Cold Regions Research and Engineering Laboratory in

Hanover, New Hampshire, where the meteorite was removed

by sterile procedures and the crystalline structure of the ice in

contact with the meteorite was examined in a series of

orthogonal thin sections. This study was undertaken to

determine if the crystalline properties of the ice were consistent

with the notion that the ice enclosing the meteorite is coeval

with the terrestrial age of the meteorite.

Anthony J. Gow, US. Army Cold Regions Research and Engineering

Laboratory, 72 Lyme Road, Hanover, New Hampshire 03755-1290.

William A. Cassidy, Department of Geology and Planetary Science,

University of Pittsburgh, Pittsburgh, Pennsylvania 15260.

Sample Processing

Prior to processing, the ice block was remeasured and

photographed from several different directions. Figure 10-1

shows the disposition of the meteorite in the ice prior to cutting

the block with a band saw. A narrow sublimation cavity around

the meteorite (Figure 10-2) was rimmed by sublimation

crystals and contained sparse grains of a fine, reddish dust

which could have been derived from the meteorite, but might

be windblown terrestrial contamination. The ice block

displayed three mutually perpendicular sets of parallel cracks,

which were features observed at the find site.

Saw cuts were made on either side of the meteorite and the

block was then split apart by wedging, as illustrated in Figure

10-3. A close-up view of the meteorite still embedded in one

wall of the cleaved ice is shown in the Frontispiece. Inspection

of the ice in contact with the meteorite showed no trace of

melting anywhere along the contact margin. The meteorite was

removed with a pair of pre-cleaned tongs (Figure 10-4) and

transferred to a polyethylene bag. This bag was then enclosed

in a second bag (as is done in the field) and placed in a

thick-walled styrofoam container, which was then filled with

dry ice and air-shipped to the curatorial facility of the NASA

Johnson Space Center, Houston, Texas. The 9.9 kilogram piece

of ice (Figure 10-5), from which the meteorite was extracted,

was shipped to Dr. K. Nishiizumi at the University of

California at San Diego for further processing and dating. As

a member of the meteorite-collecting expedition of 1983-1984,

Dr. Nishiizumi returned to the site, marked by a flag, where

the block had been removed and collected additional ice for

his analyses. Crystal structure studies were performed on thin

sections cut from slabs VI, V2, and HI in the region of the

mold of the meteorite in the other half of the sawn block

(Figure 10-5). Ice from piece V2 was also used to prepare

samples for conventional chemical analysis by J. Cragin at

CRREL and for stable isotope measurements by S. Epstein at

the California Institute of Technology. Results of these

investigations together with those of terrestrial age dating of

the meteorite are not yet available. The meteorite, ALH82102,

87
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 10-1.—Block of ice with enclosed meteorite, collected from the Allan Hills Far Western Icefield and

shipped frozen (T = -12° C) to the Cold Regions Research and Engineering Laboratory in New Hampshire.

Traces of a dominant fracture plane cross the ice from left to right. (Scale in cm).

a 48 g H5 chondrite with an almost complete fusion crust, is

described in the chapter on stony meteorites by Mason et al.,

Chapter 6.

Ice Structure Analysis

Three thin sections were cut in mutually perpendicular

directions. This was done in order to evaluate the threedimensional picture of the crystal/bubble structure of the ice.

Figure 10-6a shows a picture of Section VI, a thick (3 mm)

slice that was photographed in reflected light to show the

extremely bubbly nature of the ice. On average, bubble

abundances occur in excess of 100 per cubic centimeter of ice.

Bubble sizes seldom exceed 1 mm in diameter though

elongated bubbles in some sections of the ice may measure 2

mm or more in length. The generally irregular (non-spherical)

shapes of bubbles would suggest that they have been formed

by "exsolution," that is, were re-formed from air previously

dissolved under pressure in buried ice. Such a process was first

documented in deep ice cores from Byrd Station, Antarctica,

where bubbles in concentrations exceeding 200 per cm3 of ice

in the top 800 m had completely disappeared by 1100 m depth

(Gow et al., 1968; Gow and Williamson, 1975). Such a process

is believed to be pressure-induced since "exsolution" or

reappearance of non-spherical and generally irregularly shaped

bubbles began to occur some days after cores were pulled to

the surface. In contrast to exsolved bubbles, original bubbles

derived from air trapped between grains of snow in the upper

layers of the Antarctic Ice Sheet tend to retain rounded,

substantially spherical outlines up to the time they become

absorbed in deeper ice.

Considering probable ice temperatures upstream of the find

site (the depth at which bubbles are absorbed by the ice depends

on temperature as well as pressure), we surmise that the ice
NUMBER 28

89

FIGURE 10-2.—Closeup of the meteorite in situ, rimmed by a narrow sublimation cavity in which feathery ice

crystals protrude from the ice walls. The cavity and its crystals, observed in the field survived transport to

CRREL.

containing the meteorite must have been buried to a depth of

at least 700 m in order for complete dissolution of original air

bubbles to have occurred (Miller, 1969, and Gow and

Williamson, 1975). Based on our estimate of its burial depth

and the time needed for it to have reached the surface by

upward flow and ablation, assuming an ablation rate of 5 cm

of ice per year (see Nishio et al., 1982), the meteorite is

believed to have impacted the surface at least 30,000 years

ago. This is somewhat older than the 20,000 years that Nishio

et al. (1982) estimate for the age of ice samples located close

to Allan Hills. However, our estimate is not in disagreement

with minimum ages given by Whillans and Cassidy (1983) for

ice reaching the surface in the region of the Far Western

Icefield where the meteorite was discovered.

A photograph of the vertical section, taken in cross-polarized

light to reveal the outlines of individual crystals, is shown in

the Frontispiece of this volume. It shows a general flattening

of grains in the horizontal plane with respect to the top surface

of the ice block. The only exception is in the immediate vicinity

of the meteorite mold where crystals curve upwards. We would

attribute this curving upwards of the crystals to reaction

between the meteorite and the enclosing ice, most likely as a

result of differential deformation of ice due to the presence of

the non-deformable meteorite. In the horizontal section (Figure

10-66, Section HI) taken from near the bottom of the ice block

the crystals have become more equidimensional. Also, the

c-axes of crystals tend to be clustered together in a very broad

maximum about the vertical axis, which would be compatible

with effects due to horizontal shearing of the ice. Coarsergrained ice in immediate contact with the meteorite exhibited

no structural characteristics consistent with melting and

refreezing or annealing.

On the basis of the above observations, we conclude that the

meteorite was just beginning to emerge at the ablation surface

when discovered on 2 January 1983, and that the ice enclosing

the meteorite is coeval with the impact age of the meteorite.

The terrestrial age measurement of the meteorite therefore will

determine the age of the enclosing ice.
36 cm

SAW CUTS

10 em

FIGURE 10-3.—Splitting the ice block without touching the meteorite: a, Bill Cassidy making the first saw cut

from one edge toward the stone. A second cut was made from the opposite edge, a wedge inserted in the cut,

and the block split open. Spectators are Ursula Marvin and Tony Gow. b, diagram of the sawing and splitting

process.
NUMBER 28 91

Literature Cited

Cassidy, W.A., T. Meunier, V. Buchwald, and C. Thompson

1983. Search for Meteorites in the Allan Hills/Elephant Moraine Area,

1982-1983. Antarctic Journal of the United Sttates, 18(5):81-82.

Gow, A.J., H.T. Ueda, and D.E. Garfield

1968. The Antarctic Ice Sheet: Preliminary Results of Drilling to Bedrock.

Science, 161:1011-1013.

Gow, A.J., and T. Williamson

1975. Gas Inclusions in the Antarctic Ice Sheet and Their Glaciological

Significance. Journal of Geophysical Research, 80(36):5101-5108.

Miller, S.L.

1969. Clathrate Hydrates of Air in Antarctic Ice. Science, 165:489-490.

Nishio, F., N. Azuma, A. Higashi, and J.O. Annexstad

1982. Structural Studies of Bare Ice near the Allan Hills, Victoria Land,

Antarctica: A Mechanism of Meteorite Concentration. Annals of

Glaciology, 3:222-226.

Whillans, LA., and W.A. Cassidy

1983. Catch a Falling Star: Meteorites and Old Ice. Science, 222:55-57.

NISHIIZUMI

EPSTEIN

> (1b) 2.260 kg \ \ (1a) 1.660 kg

FIGURE 10-4.—Extraction of the meteorite at CRREL, using precleaned

stainless steel tongs and a polyethylene bag.

FIGURE 10-5.—Subsamples of the ice block. Portions of samples la, lb, VI,

and part of V2 remain at CRREL and are available for further study.

FIGURE 10-6.—Orthogonal sections through the ice: a, a vertical thick section (VI), taken in reflected light

(scale in cm), showing the very bubbly nature of the ice. The cavity that held the stone is at upper left. A

photograph of this same section after thinning, taken in cross-polarized light, is shown in the Frontispiece, b,

horizontal thin section (HI) in cross-polarized light. The grains are more equidimensional in this section. The

small gray inclusions are air bubbles (scale in cm).
11. Significance of Terrestrial Weathering Effects

in Antarctic Meteorites

James L. Gooding

Introduction

Terrestrial weathering of Antarctic meteorites represents a

mixed blessing for planetary geoscience but may be a potential

bonanza for Earth science. With respect to cosmochemistry,

weathering can produce undesirable physical, chemical, and

isotopic changes that might confuse or obscure the records of

pre-terrestrial origin and evolution that are sought in meteorites. At the same time, as an analog in comparative planetology,

the ultra-low-temperature weathering of meteorites in an icy

"regolith" represents a window into the processes of mineral

and rock alteration that have probably operated on icy planetary

bodies such as Mars, comets, asteroids, and satellites of Jupiter

and Saturn. For Earth science, terrestrial weathering effects in

Antarctic meteorites represent distinctive "marker horizons"

which, if they can be quantitatively calibrated and correlated

with other measurable properties, might yield important

information about histories of Antarctic ice sheets.

Major issues surrounding the terrestrial weathering of

Antarctic meteorites include the following questions:

1. How can weathering effects be recognized and quantified?

2. Are degrees of weathering correlated with terrestrial ages?

3. How are cosmochemical studies affected by weathering?

To date, answers to these questions have been incomplete

and unsatisfying and it is time to apply greater research

emphasis to the problem.

Recognition and Quantification of Weathering Effects

In the broadest sense, "weathering" is the collection of

processes which, through surface/atmosphere interactions,

leads to the decomposition or alteration of rocks, minerals, or

mineraloids, and the possible formation of new phases. Even

casual observations of Antarctic meteorites reveal that most

specimens are rusty and cracked and that outer surfaces are

partially eroded and discolored relative to interior surfaces that

are exposed upon chipping. Therefore, it is clear that both

James L. Gooding, Code SN2, Planetary Materials Branch, NASA/

Johnson Space Center, Houston, Texas 77058.

physical and chemical weathering have affected Antarctic

meteorites. Products of chemical weathering include carbonates, sulfates, and hydrous iron oxides (Marvin, 1980;

Gooding, 1981) as well as clay mineraloids (Gooding, 1984a,b;

1986b). Aluminosilicate weathering products, in particular, are

easily overlooked because of their small grain sizes and their

resemblance to primary felsic minerals (Figures 11-1, 11-2).

Because rust is so common and conspicuous, however, degree

of rustiness has been adopted as the conventional means for

expressing the "degree of weathering" of a given specimen.

Under the current curatorial practices that apply to the

American collection, preliminary examination and classification of each Antarctic meteorite specimen includes assignment

to an A, B, or C weathering type according to the following,

generalized definitions:

A: Minor rustiness; rust haloes on metal particles and

rust stains along fractures are minor.

B: Moderate rustiness; large rust haloes occur on metal

particles and rust stains on internal fractures are

extensive.

C: Severe rustiness; metal particles have been mostly, if

not totally, converted to rust and the specimen is

stained by rust throughout.

Unfortunately, the A-B-C system is only qualitative and its

application is largely subjective. In addition, its dependence

on meteoritic metal as an index phase makes it difficult, if not

impossible, to apply uniformly to all types of meteorites. Not

only is it difficult to compare achondrites with chondrites by

the A-B-C system, but comparisons within either group can

be just as problematical, as exemplified by the case of aubrites

vs. eucrites or the case of H-chondrites vs. C-chondrites,

respectively. In practice,the A-B-C assignment for a meteorite

that contains little or no metal is based mostly on overall

rustiness that has developed by weathering of iron sulfides or

mafic silicates.

Reflectance spectrophotometry might offer a means of more

objectively and quantitatively ranking meteorite specimens

according to their degrees of rustiness. As shown in Figure

11-3, there appears to be an inverse correlation between

93
94 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 11-1.—Scanning electron image of Antarctic weathering products that fill cavities in the fusion crust

of the "emerging stone," ALH82102 (H5 chondrite). The etched appearance of portions of the fusion crust

suggests aqueous leaching whereas the vug fillings clearly suggest aqueous precipitation. Points A and B

correspond to elemental analyses that are depicted in Figure 11-2. Scale bar is 10 |lm.

measurable "redness" and measurable degree of iron oxidation

for ordinary chondrites. The trend is most clear for samples of

the Holbrook, Arizona chondrite that were recovered at

different times after its fall to Earth in 1912. As previously

noted (Gibson and Bogard, 1978), the 1931 Holbrook specimen

appears to be more weathered than the 1968 specimen even

though the same climate prevailed during weathering of both

specimens. Therefore, variations among microenvironments

(depth of burial in soil, quality of drainage, etc.) that apparently

affected weathering of Holbrook specimens must be considered

in deducing the weathering histories of Antarctic meteorites.

Not only are differences in Antarctic weathering to be expected

between meteorites found in moraines and those found on open

ice sheets, but differences in degrees of weathering among

finds on ice sheets might exist as a function of the time that

each specimen spent encased in ice relative to the time that it

spent exposed at the ice/atmosphere surface (Gooding, 1986a).

Results for the Antarctic L6 chondrites in Figure 11-3

underscore one of the deficiencies of the A-B-C system. Even

though all three L6-chondrite specimens were categorized as

transitional A/B in terms of degree of weathering, they yield

substantially different values for the spectrophotometric index

and possibly also for the rust index (note that a relatively small

change in the ratio total-Fe/(FeO + FeS) corresponds to a

significant change in oxidation state). Therefore, at least in its

present form, the A-B-C system of categorizing degree of

weathering should not be considered quantitative and should

not be overinterpreted. Indeed, a reliable and quantitative index
flLH82182,S flLUMINOSILICflTE/S flLH82182,Sfl-88HD/lSKV

1888

COUNTS

ENERGY (KEY)

18.8

HLH82182.5 GLflSSY FUSION CRUST flLH82182,Sfl-88HB/15KV

1888

COUNTS

ENERGY IKEVJ 18.8

FIGURE 11-2.—Energy-dispersive x-ray emission spectra for areas on the fusion crust of ALH82102 as depicted

in Figure 11-1. (A) complex weathering-product assemblage, possibly consisting of silica and/or an

aluminosilicate mixed with a sulfate, that fills a cavity. (B) fusion crust, representing approximately the

pre-terrestrial bulk major-element composition of the meteorite. Note the elemental fractionations that have

occurred during weathering of the fusion crust (i.e., A vs. B).
96 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

0.9 -

0.8 -

0.7 -

0.6 -

0.5 -

0.4

1 1 1

WEATHERED CHONDRITES:

SPECTROPHOTOMETRY VS. RUST INDEX

O ALHA77296

1912 • (A/B)

ALHA77270 TM

(A/B)

 H 6

ALHA77155

(A/B) A

O

196 8

•

ALHA76008

(B/C)

I I

o

•

L6

HOLBROOK,

ARIZONA

(L6)

ALLAN HILLS,

ANTARCTICA

-

O1931

I

2 3

WEIGHT RATIO TOTAL Fe/(Fe° + FeS)

FIGURE 11-3.—Ratio of diffuse spectral reflectance at 0.5 Jim wavelength to

that at 0.6 \im, as a function of an independently determined "rust index" that

is based on the oxidation of meteoritic metal and troilite. Decrease in the value

of the spectrophotometric ratio corresponds to an increase in the visually

perceptible degree of reddish coloration. Increase in the rust index corresponds

to increase in degree of terrestrial oxidation. Each reflectance target was

prepared by pulverizing and homogenizing a visually representative sample

from the outer 1 cm of the specimen. Spectrophotometric data are from

Gooding (1981) whereas chemical data are from Gibson and Bogard (1978)

and Jarosewich (1984).

for degree of weathering remains a major need in research on

Antarctic meteorites. Attention must be paid to the fact that

oxidation of iron is only one of several processes that occur

during Antarctic weathering and that, because of the wide

variation of metal and total iron contents among meteorites, a

simple rust index might not be the best measure of degree of

weathering.

Correlations between Weathering and Terrestrial Age

The situation can be stated succinctly: no correlation

between degree of weathering and terrestrial residence age has

yet been demonstrated for Antarctic meteorites. It is intuitively

reasonable to suspect that, at least for a given meteorite type

(e.g., L6 chondrite), degrees of weathering among Antarctic

specimens might be correlatable with the lengths of time that

the specimens have spent on Earth. Either the presence or

absence of such a correlation would be of great significance

in efforts to identify the mechanisms that are responsible for

transportation and concentration of meteorite specimens by

Antarctic ice.

Previous conclusions regarding the absence of a correlation

between degree of weathering and terrestrial residence age

have relied on the fact that no systematic increase in terrestrial

age occurs with alphabetic letter among specimens that have

been categorized by A-B-C designations (e.g., Nishiizumi,

1986). As discussed above, though, weathering types defined

by the A-B-C system cannot be treated as quantitative

classifications. Consequently, the apparent lack of correlation

between terrestrial age and degree of weathering might only

reflect the irreconcilable mixture of quantitative measurements

with qualitative estimates. Further progress on this problem

cannot be expected until a quantitative index for degree of

weathering is developed.

As shown in Figure 11-4, there may exist sensible inverse

correlations between the spectrophotometric rust index and

terrestrial age. Chondrites from Allan Hills, Antarctica, appear

to have rusted much more slowly than did the Holbrook

samples, based on the observation that the slopes of their

respective trendlines differ by a factor of 10. Not surprisingly,

the metal-rich H-chondrites seem to be systematically more

rusty than the L6 chondrites among the Antarctic specimens.

For the few data that are available, the trends in Figure 11-4

are not impressive but suggest that further work along these

lines might produce a much better test of weathering/age

correlations than has been made to date.

Possible Consequences for Cosmochemistry

Ultrasensitive analytical techniques and interpretive models

that comprise current wisdom in cosmochemistry were

developed mostly from experience with lunar samples and

freshly fallen meteorites (Allende, Murchison, etc.). However,

none of the meteorites recovered from Antarctica can be

considered "pristine." Elemental fractionations occur during

weathering (Jarosewich, 1984) although the degree to which a

particular chemical study is likely to be affected might be

determined largely by the samples and methods that are

employed. Although untreated aliquots that are isochemically

weathered at the scale of sampling may appear undisturbed in

bulk analyses, disturbances may become apparent in analyses

that sample a meteorite at less than the scale of weathering

(e.g., aliquots of a few milligrams) or that depend upon

mineralogical or ion-exchange separations or gas extractions.

Phase locations and solubilities of analyte species are subject

to change by chemical weathering.

Textural relationships between weathering products and

their hosts clearly show that aqueous transportation has played

a key role during weathering of Antarctic meteorites (Gooding,

1981, 1986b; Figure 11-1). In at least some cases, aqueous

leaching and precipitation have produced significant elemental

fractionations between the progenitors and products of

chemical weathering (Figure 11-2). The same aqueous

geochemical processes might be responsible for the uptake or

loss, as well as the internal redistribution, of other elements.

Pre-terrestrial gases can be lost by solution weathering of their

host phases, whereas terrestrial gases can be incorporated

during growth of secondary minerals and mineraloids.
NUMBER 28 97

WEATHERED CHONDRITES:

SPECTROPHOTOMETRY VS. TERRESTRIAL AGE

0.9

0.8

0.7

0.6

0.5

0.4

o L6 H6

E

(O

d

-^

?

a.

d

cr

1912

ALHA77296 (A/B)

\ 1968

\

o

Y

ALLAN HILLS,

ANTARCTICA

(SLOPE =-0.016)

'HOLBROOK,

ARIZONA

(SLOPE = -0.16)

1931

ALHA77270

•——__• _ (A/B)

m ALHA77272

W

 (B/C)

9 ALHA77155

" (A/B)

ALHA76008

(B/C)

o

ALHA76006

(C)

3 4 5

LOG t (TERR) (Y)

FIGURE 11-4.—Spectrophotometric index (defined in Figure 11-3) as a function of terrestrial residence age.

Terrestrial ages of Antarctic specimens are from the compilation by Nishiizumi (1984). Trendlines represent

linear least-squares fits through the respective data points. The "Allan Hills" trendline is defined by ALHA77270,

ALHA77272, and ALHA77296, assuming Holbrook-1912 as the control point for an unweathered L6 chondrite.

No terrestrial age has been published for ALHA77155.

Lipschutz (1982) briefly reviewed published trace-element

data for Antarctic meteorites in the context of the weathering

problem and concluded that loss of elements by natural

leaching is the most serious problem but that, by restriction of

work to samples from >1 cm depth in type A specimens, bulk

trace-element analyses can be obtained for Antarctic meteorites

without interference from weathering effects. Unfortunately,

many of the most interesting Antarctic specimens are small

(e.g., lunar meteorite ALHA81005: 3 cm maximum dimension)

and the 1 cm depth criterion has not been applied during

sampling. Furthermore, at least some type A specimens contain

non-rusty weathering products (salt minerals, clay mineraloids)

that might constitute important sources of interference in other

types of analyses, especially isotopic and gas analyses. For

example, the shergottites EETA79001 and ALHA77005 were

both categorized as type A even though they contain

aluminosilicate weathering products of the types that can be

expected to be strong and fractionating sorbents of gases

(Gooding, 1984b).

Clayton et al. (1984) reported effects of Antarctic weathering

in some of their oxygen isotopic analyses and Kaneoka (1984)

and Spangler and Warasila (1985) presented clear evidence for

disturbance by weathering of K-Ar systematics in both

chondrites and achondrites from Antarctica. Disturbance of

noble gas abundances occurred during weathering of the

Holbrook chondrite (Gibson and Bogard, 1978) but, unfortunately, comparison of results for Holbrook with results for

Antarctic specimens might be less straightforward than

expected. Although rust in Antarctic L-chondrites is very

similar to that in Holbrook (Gooding, 1981), Antarctic

specimens also contain non-rusty aluminosilicates and salt

minerals (Figures 11-1, 11-2) that are rare to absent in

Holbrook. Therefore, effects of Antarctic weathering on

cosmochemical properties of meteorites might be significantly

different from effects of temperate-latitude weathering.

Ideally, every Antarctic meteorite sample that is destined for

a critical cosmochemical analysis should first be mineralogically examined for overall evidence of weathering (not just

rustiness) so that problems (and possible data corrections) can

be assessed in advance of sample consumption. Such

precautions are especially important for studies that attempt

to define new meteorite groups or sub-divide previously

recognized meteorite groups using elemental or isotopic

parameters that might be sensitive to disturbance by weathering.

Summary

The current inadequate understanding of weathering histories of Antarctic meteorites, and their possible effects on
98 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

measurable properties of the specimens, stems from a general

lack of attention to the problem. A first major element of

progress would be to augment or replace the currently used

A-B-C system of categorizing degree of weathering with a

system that is more objective and quantitative. Reflectance

spectrophotometry might be a useful method for quantifying

degree of rustiness although other methods may be required

to quantify abundances of non-rusty weathering products.

Literature Cited

Clayton, R.N., T.K. Mayeda, and K. Yanai

1984. Oxygen Isotopic Compositions of Some Yamato Meteorites. In

Proceedings of the Ninth Symposium on Antarctic Meteorites.

Memoirs of National Institute of Polar Research (Japan), special

issue, 35:267-271.

Gibson, E.K., Jr., and D.D. Bogard

1978. Chemical Alterations of the Holbrook Chondrite Resulting from

Terrestrial Weathering. Meteoritics, 13:277-289.

Gooding, J.L.

1981. Mineralogical Aspects of Terrestrial Weathering Effects in Chondrites from Allan Hills, Antarctica. In Proceedings of the Twelth

Lunar and Planetary Science Conference, pages 1105-1122. New

York: Pergamon Press.

1984a. Low-Temperature Aqueous Alteration in the Early Solar System:

Possible Clues from Meteorites Weathered in Antarctica. In Lunar

and Planetary Science XV, pages 308-309. Houston: Lunar and

Planetary Institute.

1984b. Search for "Martian(?) Weathering" Effects in Achondrites

EETA79001 and ALHA77005: Complications from Antarctic

Weathering. In Lunar and Planetary Science XV, pages 310-311.

Houston: Lunar and Planetary Institute.

1986a. Weathering of Stony Meteorites in Antarctica. In J.O. Annexstad,

L. Schultz, and H. Wanke, editors. Workshop on Antarctic

Meteorites. LPI Technical Report, 86-01:48-54. Houston: Lunar and

Planetary Institute.

1986b. Clay-mineraloid Weathering Products in Antarctic Meteorites.

Geochimica et Cosmochimica Acta, 50:2215—2223.

Jarosewich, E.

1984. Bulk Chemical Analyses of Antarctic Meteorites, with Notes on

Weathering Effects on FeO, Fe-metal, FeS, H2O, and C. In U.B.

Marvin and B. Mason, editors, Field and Laboratory Investigations

of Meteorites from Victoria Land, Antarctica. Smithsonian Contributions to the Earth Sciences, 26:111-114.

Kaneoka, I.

1984. Characterization of Ar-Degassing from Antarctic Meteorites. In

Proceedings of the Ninth Symposium on Antarctic Meteorites.

Memoirs of National Institute of Polar Research (Japan), special

issue, 35:272-284.

Lipschutz, M.E.

1982. Weathering Effects in Antarctic Meteorites. In U.B. Marvin and B.

Mason, editors, Catalog of Meteorites from Victoria Land,

Antarctica, 1978-1980. Smithsonian Contributions to the Earth

Sciences, 24:67-69.

Marvin, U.B.

1980. Magnesium Carbonate and Magnesium Sulfate Deposits on

Antarctic Meteorites. Antarctic Journal of the United States,

XV(5):54-55.

Nishiizumi, K.

1984. Cosmic-Ray-Produced Nuclides in Victoria Land Meteorites. In

U.B. Marvin and B. Mason, editors, Field and Laboratory

Investigations of Meteorites from Victoria Land, Antarctica.

Smithsonian Contributions to the Earth Sciences, 26:105-109.

1986. Terrestrial and Exposure Histories of Antarctic Meteorites. In J.O.

Annexstad, L. Schultz, and H. Wanke, editors. Workshop on

Antarctic Meteorites. LPI Technical Report, 86-01:48-54. Houston:

Lunar and Planetary Institute.

Spangler, R.R. and R.L. Warasila

1985. 39Ar-40Ar Ages of ALHA77302, 77256, and 77219. In Lunar and

Planetary Science XVI, pages 805-806. Houston: Lunar and

Planetary Institute.
12. Trace Element Variations between Antarctic (Victoria Land)

and Non-Antarctic Meteorites

Michael E. Lipschutz

Studies, mainly of contemporary meteorite falls, reveal that

the Earth is today sampling 70-80 parent bodies (Dodd, 1981)

and/or source regions. These are far fewer than the 3330

numbered asteroids (Marsden, 1985), let alone the 15,000

discovered by the Infrared Astronomy Satellite (Tedesco,

1984). Even if non-Antarctic finds are considered to be heavily

biased toward irons because of their recognition factor and

greater resistance to weathering, the number of extraterrestrial

sources is not increased markedly. Has the Earth always

sampled the same few sources, or has the meteoroid complex

varied in time or space?

Until the Antarctic meteorite discoveries, this question could

not be addressed, since most witnessed falls have occurred

during the most recent 200 years before present (B.P.).

Non-Antarctic finds extend this to 1000-10,000 years B.P. but

their utility is limited because many meteorites are degraded

and contaminated during weathering in warmer latitudes. This

is too short an interval in which to expect a detectable temporal

source variation. Antarctic meteorites allow a farther look

backward since their terrestrial ages generally are 0.1-0.7 Myr

B.P. (Bull and Lipschutz, 1982) and, with some caveats,

weathering has not reduced their scientific value (Lipschutz,

1982; Dennison and Lipschutz, in prep. a). While terrestrial

age distributions for meteorites from Victoria Land and Queen

Maud Land overlap, these two major Antarctic sample

populations have different mean ages—0.3 and 0.1 Myr B.P.,

respectively—and mass distributions that differ from each

other and from those of non-Antarctic falls (Bull and Lipschutz,

1982). In view of these differences, these three sample

populations are treated here as different ones—referring to

each by name: the adjective "Antarctic" will be applied when

specific sample population designation is unnecessary.

Because relatively few Antarctic meteorite fragments

recovered to date (over 1900 by the United States-led Antarctic

Search for Meteorites and over 5100 by the Japanese Antarctic

Research Expedition teams) can be paired with confidence, the

Michael E. Lipschutz, Department of Chemistry, Purdue University,

W. Lafayette, Indiana 47907.

number of distinct meteorite events represented by the

Antarctic finds is somewhat uncertain. Many Antarctic

specimens are unpaired but a very few have numerous

well-established siblings, numbering up to 148 (Mason and

Yanai, 1983). Taking an overall average of 5 fragments per

fall (estimated as 2-6 per fall by Scott, 1984), the Antarctic

population represents about 1400 distinct events. This number

is comparable (within a factor of 2) to the 2611 known, distinct

non-Antarctic meteorites currently cataloged (Graham et al.,

1985).

From the first, it was recognized that the Antarctic

population includes a substantial number of meteorites of rare

or unique type compared with the non-Antarctic ones

(Kusunoki, 1975). Subsequently, recovery and study of such

exciting specimens has proven to be very nearly an annual

event as, for example, in the cases of lunar and putative Martian

meteorites (Marvin, 1983; Yanai and Kojima, 1984). Representatives of some rare types resemble their non-Antarctic

congeners but, curiously, often show subtle differerences from

them in composition. This seems to reflect preterrestrial

processes rather than terrestrial weathering (Biswas et al., 1980,

1981; Lipschutz, 1982). Antarctic and non-Antarctic meteorites

differ in other ways. For example, general differences occur

in the distribution of iron meteorite chemical groups (Clarke,

1986) and in the textures and mineral compositions of Antarctic

and non-Antarctic diogenites and eucrites (Mason and Yanai,

1983). Of course, these comparisons are based on poor

statistics since we are dealing with representatives of rare

meteorite types.

Subject to inevitable uncertainty because of pairing problems, Antarctic and non-Antarctic populations differ in their

constituent meteorite proportions. Considering just the most

general classification (Table 12-1), the Victoria Land population (corrected for known pairing) contains fewer irons, LL

chondrites, and perhaps stony-irons than do non-Antarctic falls.

Furthermore, the high iron to low iron (H/L) chondrite ratio is

over 3 in the Victoria Land population and 1 in non-Antarctic

falls (and finds). In the only comprehensive study of a single

year's (1974) collection in Queen Maud Land, Mason and

99
100 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Yanai's (1983) data yield an HA- chondrite ratio (corrected for

paired samples) of 155/54, or nearly 3. These differences

cannot reasonably be ascribed to Antarctic weathering; they

hint at some major difference in the nature of meteorites

landing in Antarctica and those landing elsewhere. Possibly

the parent bodies of Antarctic meteorites followed more highly

inclined orbits, or, more likely, a temporal change has taken

place in the meteorite flux (Dennison et al., 1986).

Indications for differences between meteorite types in

Antarctic and non-Antarctic sample populations do not

necessarily mean that any given meteorite type will differ in

the two sample populations. To identify the significant

differences, one must compare parameters known to vary

widely and be indicative of meteoritic genetic processes.

Volatile and/or mobile trace element contents (Ag, Au, Bi, Cd,

Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, and Zn) provide such a

parameter for comparison between non-Antarctic ordinary

chondrite falls and Victoria Land chondrites.

Data for a given volatile/mobile trace element in a sample

population distribute either normally or lognormally and may

be treated as Gaussian in either case (Dennison et al., 1986).

Generally, distributions for a given element in two sample

populations overlap and one must use standard statistical tests

to examine the likelihood that the sample populations derive

from the same parent population. If, statistically, this is

unlikely for a number of different elements, it may be

concluded that the sample populations derive from different

parent populations.

As part of a series of systematic studies of equilibrated

ordinary chondrites, Dennison et al. (1986) compared volatile/

mobile trace element data for 23 Antarctic finds and 20

non-Antarctic H5 chondrite falls. Taking >95% confidence

level as significant and 90%-94% as possibly so, Dennison

et al. (1986) found differences for 8 of 13 elements tested

(Table 12-2). This greatly exceeds the proportion expected to

arise by chance (1-2 of 13 elements at the >90% confidence

level). Dennison et al. (1986) and Dennison and Lipschutz (in

prep. a,b) extended the comparison to H4-6 chondrites. They

considered a variety of more or less plausible explanations for

the differences, especially weathering, and concluded that the

difference was a real one reflecting preterrestrial genetic

differences. More recently, Kaczaral and Lipschutz (in prep.)

found that L4-6 chondrites from Victoria Land also differ

compositionally from non-Antarctic falls: we take this as

additional support for the unimportance of a weathering effect

on trace element contents of Antarctic meteorites.

For L6 chondrites, the trace element data suggest, on

average, more severe thermal processing (perhaps by shock)

for the Victoria Land samples than for non-Antarctic falls

(Kaczaral and Lipschutz, in prep.). This suggestion is currently

being tested by petrographic and thermoluminescence studies.

For H5 chondrites, genetic processes responsible for the

compositional differences are less obvious (Dennison and

Lipschutz, in prep. b).

TABLE 12-1.—Comparative numbers of selected meteorite types found in

Victoria Land and falling in non-Antarctic regions (numbers cited for H, L,

and LL chondrites count as part of the total for chondrites).

Meteorite type

Chondrites

H

L

LL

Achondrites

[rons

Stony Irons

Total

Victoria Land*

No.

756

542

167

24

45

14

3

818

%

92.4

66.3

20.4

2.9

5.5

1.7

0.4

100.0

Non-Antarcticf

No.

784

276

319

66

69

42

10

905

%

86.6

30.5

35.2

7.3

7.6

4.6

1.1

100.0

*J. Gooding (personal communication, 1985). Data do not include 281

samples paired with ones already classified.

tGraham et al. (1985).

Major and trace element distributions for ordinary chondrites

from Victoria Land are more coherent than those for

non-Antarctic falls (Fulton and Rhodes, 1984; Dennison et al.,

1986; Dennison and Lipschutz, in prep. a,b; Kaczaral and

Lipschutz, in prep.), hinting again at preterrestrial compositional differences between Antarctic and non-Antarctic meteorites. Dennison et al. (1986) illustrate one in which meteorite

sample populations falling on Earth at specific times in the

past could differ in the proportions of constituent types. Such

distributions preserved, for example, in the Antarctic ice sheet

would constitute "snap-shots in time" of the meteoroid

distribution. As yet, we do not know whether the Antarctic

sample population is a single one or if the Victoria Land and

Queen Maud Land (and others) constitute differing sample

populations separated in time, having average ages of 0.3 Myr

B.P. (Victoria Land) and 0.1 Myr B.R (Queen Maud Land) (Bull

and Lipschutz, 1982). Another possibility is that Antarctic

meteorites preferentially derive from parent bodies in highly

inclined orbits.

It seems too optimistic to expect that the Victoria Land

population is a "pure" sample of a single parent region (or

body) "unsullied" by earlier and later events, and it would be

premature to attempt resolution of the near-Earth meteorite

flux with only 2 distributions, Victoria Land and non-Antarctic

falls. Indeed, it is astonishing that any differences are detectable

in chondrite sample populations separated by only 0.2 Myr,

when typical cosmic ray exposure ages had been taken to imply

an averaging of the chondritic flux over the past 1-10 Myr

(Wetherill, 1974).

Nevertheless, the trace element evidence seems compelling

that meteorites from Victoria Land sample a population

different from that falling today in non-Antarctic regions.

Hence, Antarctic meteorites are a more valuable scientific

resource than hitherto suspected. Antarctic meteorites may

include collision debris from disrupted parent asteroids that

was long since swept up and no longer exists among
NUMBER 28 101

TABLE 12-2.—Comparison of statistically significant differences in H5 and L6 chondrites from

Victoria Land, Antarctica, with contemporary non-Antarctic falls. (Ant. = Chondrites from Victoria

Land; Non = non-Antarctic chondrite falls; Sig. = significance level at which it may be concluded

that the respective sample populations do not derive from the same parent population. Numbers in

parentheses are number of samples analyzed in that population.)

Element

Co (ppm)*

Au (ppb)*

Sb (ppb)

Se (ppm)*

Rb (ppm)

Cs (ppb)

Te (ppb)

Bi (ppb)

Ag (ppb)

In (ppb)

Tl (ppb)

Zn (ppm)*

Cd (ppb)

Ant. (23)

83

9.0

2.0

2.8

0.21

0.81

43

0.72

H5

Non (20)

69

8.2

2.5

1.1

0.49

0.24

53

3.7

Sig.

97

99

97

98

96

96

96

99

Ant. (13)

480

140

2.6

4.02

340

0.58

45

1.6

L6

Non (25)

600

160

2.2

12.4

380

2.7

71

14.2

Sig.

97

90

95

99

90

99

97

99

*Arithmetric means, all others are geometric means: the specific choice is determined by the data

distribution in the populations tested. Further information (e.g., standard deviation, etc.) is in

Dennison et al. (1986) and Kaczaral and Lipschutz (in prep.).

contemporary falls elsewhere on Earth. From the standpoint

of studies of extraterrestrial materials and processes, Antarctic

meteorites offer the potential of an enhanced understanding of

planetary surfaces, the genesis, evolution, and composition of

meteorite planet bodies, and temporal variations in meteorite

and cosmic ray fluxes.

Furthermore, since the fall of Antarctic meteorites can be

dated, they provide a potential source of information on the ice

sheet region with which they are associated. Ancillary

measurements, in concert with meteoritic terrestrial ages, could

provide information on the ancient trapped atmosphere, ice

sheet dynamics, and oxygen isotopic variations, leading to a

predictive model for discovering new meteorite concentrations.

ACKNOWLEDGMENTS.—This research would not have been

possible except for the aid of the staff of the University of

Missouri Research Reactor, irradiation support through DOE

grant DEFG 0280 ERR 10725 and research support by NASA

grant NAG 9-48 and NSF grants DPP-8111513 and 8415061.

Literature Cited

Biswas, S., H.T. Ngo, and M.E. Lipschutz

1980. Trace Element Contents of Selected Antarctic Meteorites, I:

Weathering Effects and ALH A77005, A77257 and A77299.

Zeitschrift fur Naturforschung, 35a: 190-196.

Biswas, S., T.M. Walsh, H.T. Ngo, and M.E. Lipschutz

1981. Trace Element Contents of Selected Antarctic Meteorites, II:

Comparison with Non-Antarctic Specimens. Memoirs of the

National Institute of Polar Research (Japan), special issue

20:221-228.

Bull, C.B.B., and M.E. Lipschutz

1982. Workshop on Antarctic Glaciology and Meteorites. Lunar and

Planetary Institute Technical Report, 82-03:22.

Clarke, R.S., Jr.

1986. Antarctic Iron Meteorites: An Unexpectedly High Proportion of

Falls of Unusual Interest. In J.O. Annexstad, L. Schultz, and H.

Wanke, editors, Workshop on Antarctic Meteorites. Lunar and

Planetary Institute Technical Report, 86-01:28-29.

Dennison, J.E., and M.E. Lipschutz

In prep. a. Chemical Studies of H Chondrites—II: Weathering of

Antarctic Samples.

In prep. b. Chemical Studies of H Chondrites—III: Antarctic H4-6

Samples.

Dennison, J.E., D.W. Lingner, and M.E. Lipschutz

1986. Antarctic and Non-Antarctic Meteorites for Different Populations.

Nature, 319:390-393.

Dodd, R.T.

1981. Meteorites, A P etrologic-Chemical Synthesis. 368 pages. Cambridge, England: Cambridge University Press.

Fulton, C.R., and J.M. Rhodes

1984. The Chemistry and Origin of the Ordinary Chondrites: Implications

from Refractory-Lithophile and Siderophile Elements. In Proceedings of the Fourteenth Lunar and Planetary Science Conference.

Journal of Geophysical Research, 89(supplement): B543-B558.

Graham, A.L., A.W.R. Bevan, and R. Hutchison

1985. The Catalogue of Meteorites. 4th edition, 460 pages. London: British

Museum.

Kaczaral, P.W., and M.E. Lipschutz

In prep. Chemical Studies of L Chondrites, IV: Antarctic L4-6 Chondrites

and Their Origin.

Kusunoki, K.

1975. A Note on the Yamato Meteorites Collected in December 1969.

Memoirs of the National Institute of Polar Research (Japan), special

issue, 5:1-8.
102 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Lipschutz, M.E.

1982. Weathering Effects in Antarctic Meteorites. In U.B. Marvin and B.

Mason, editors, Catalog of Meteorites from Victoria Land,

Antarctica, 1978-1980. Smithsonian Contributions to the Earth

Sciences, 24:67-69.

Marsden, B.G.

1985. Minor Planet Circular, 10063.

Marvin, U.B.

1983. The Discovery and Initial Characterization of Allan Hills 81005:

The First Lunar Meteorite. Geophysical Research Letters, 10:775-

778.

Mason, B., and K. Yanai

1983. A Review of the Yamato-74 Meteorite Collection. Memoirs of the

National Institute of Polar Research (Japan), special issue, 30:7-28.

Scott, E.R.D.

1984. Pairing of Meteorites Found in Victoria Land, Antarctica. Memoirs

of the National Institute of Polar Research (Japan), special issue,

35:102-125.

Tedesco, E.F.

1984. IRAS Asteroid Workshop No. 3. Jet Propulsion Laboratory

(Pasadena) Report, D-1617.

Wetherill, G.W.

1974. Solar System Sources of Meteorites and Large Meteoroids. Annual

Review of Earth and Planetary Science, 2:303-331.

Yanai, K., and H. Kojima

1984. Lunar Meteorites in Japanese Collection of the Yamato Meteorites.

Meteoritics, 19:342-343.
13. Pairing of Meteorites from Victoria Land

and the Thiel Mountains, Antarctica

Edward R.D. Scott

Introduction

The identification of meteorite specimens that belong to the

same fall is useful for a variety of reasons: it minimizes

unnecessary duplication of research, waste of specimens, and

conserves curatorial resources. It can also improve our

understanding of the mechanisms that preserve and transport

meteorites in Antarctica. This article reviews what is known

about possible pairings among Victoria Land and Thiel

Mountains specimens and is based largely on lists of paired

specimens in the Antarctic Meteorite Newsletters and a

previous review (Scott, 1984b). The Newsletter lists were

compiled largely by R.A. Score, B. Mason, and C. M. Schwarz

from their own petrologic studies of thin sections and specimen

exteriors. Estimates of the reliability of these pairings are

included here, as well as an assessment of the number of

unidentified pairings.

Coordinates of the discovery locations of -76 to -78

specimens have been published by Yanai (1982, 1984).

Discovery locations have not been published for other

specimens, except for 18 Reckling Peak samples found during

the 1979-1980 season (Cassidy and Rancitelli, 1982). However, geographic propinquity is only one guide to pairing as

Antarctic specimens found less than a meter apart may belong

to different falls, whereas specimens recovered 20 km apart

may be paired. In addition, it is likely that strong winds can

transport even 200-gram specimens over distances of many

kilometers (Scott, 1984b).

Table 13-1 lists all proposed pairings among Victoria Land

and Thiel Mountains specimens (excluding typographical

errors in the Antarctic Meteorite Newsletters). Estimates of the

reliability of these pairings were made by evaluating the criteria

used for pairing, and by comparing studies of paired specimens

using different techniques (Scott, 1984b). For type 3 ordinary

chondrites, irons, most achondrites, and carbonaceous chondrites, which are all relatively uncommon, there is general

Edward R.D. Scott, Department of Geology and Institute of

Meteoritics, University of New Mexico, Albuquerque, New Mexico

87131.

agreement between different investigators. However, for many

type 4 to type 6 ordinary chondrites, and some polymict

eucrites, mesosiderites, and CM2 chondrites, there are disagreements among petrologists and noble gas and cosmogenic

nuclide analysts. In most cases, proposed pairings have not

been tested by other investigators, so that there are considerable

uncertainties in many of the confidence levels listed in Table

13-1.

With the exception of cosmogenic nuclide studies, there

have been few investigations of chemical and mineralogical

variations in large (multikilogram) meteorites. This enhances

the difficulties in pairing Antarctic specimens, especially for

brecciated meteorites such as the polymict eucrites. We do not

know whether, for example, a 15% difference in the plagioclase

content of then sections of two polymict eucrites or a 40%

difference in the Cr concentrations of 2-gram samples of two

ordinary chondrites provides good evidence against pairing.

Table 13-1 also includes one to four references for each

group of paired specimens; additional references are given in

Scott (1984b). Where possible, references are placed opposite

the specimens to which they refer, but in some cases a paper

may also refer to specimens on different lines of the same

pairing group. A numerical list of the specimens in Table 13-1

is given in Table 13-2 together with the pair number and

confidence level given in Table 13-1. These tables show that

the proportion of specimens with suggested pairings from a

given field season has decreased from 1977 to 1981: 75% of

the 102 ALHA77- samples classified by Score et al. (1982b)

are listed in the pairing tables, but only 22% of the 313

characterized ALHA81- specimens. This is partly because field

investigators since Cassidy (1980) have not published suggested pairings, but also because the preliminary examination

teams have begun to concentrate their efforts on identifying

pairs of the rarer meteorites. This change is reasonable as few

researchers study type 4-6 ordinary chondrites, and pairings

among rarer meteorites are easier to identify. The proportion

of types 4-6 ordinary chondrites among lists of paired

specimens is 75% for pairing lists published in 1982 and 1983

{Antarctic Meteorite Newsletter, 5(1) and 6(2)), close to the

103
104 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 13-1.—Meteorite specimens that have been paired and the confidence levels of these pairings (confidence

level: a = high (>95%); b = medium (80% - 90%; c = low (50% -75%); x = unpaired or highly uncertain pairing).

Pair

number Specimens

Confidence

level References

UNGROUPED METEORITES

1.1 ALHA77081, 81261, 81315

EUCRITES AND HOWARDITES

2.1 ALHA76005, 77302,78040,78132, 78158,

78165,79017,81009

80102, 81006-81008, 81010, 81012

81001

2.2a EETA79004, 79011, 83228, 83229, 83231,

83232, 83234, 83251, 83283

2.2b EETA79005, 79006, 82600, 83227, 83235

Alternative view

2.2a EET83231,83232

79004

2.2b EETA79011,83229, 83234, 83283

2.2c EETA79005, 79006, 82600, 83212, 83227,

83228, 83235, 83251

AUB RITES

3.1

3.2

3.3

UREILITES

3.4

3.5

ALH83009, 83015

ALH84007, 84008, 84011

EET83246, 83247

ALHA78019, 78262

ALH82106, 82130

MESOSIDERTTES

IRONS, GROUP IIB

5.2 DRPA78001-78016

CM2 CHONDRITES

6.1 ALHA81002, 81004, 82100

78261,82131,83016

77306

6.2 ALH83100, 83102, 84029 - 84032, 84034,

84042, 84044

CO3 CHONDRITES

6.3 ALHA77003,82101

CV3 CHONDRITES

9.10 ALHA81OO3,81258

EH3/4 CHONDRITES

7.1 ALHA77156,77295

81189

E6 CHONDRITES

7.2 ALHA81021,81260

4.1

4.2

IRONS,

5.1

ALHA77219, 81059, 81098

RKPA79015, 80229, 80246, 80258, 80263

GROUPIA

ALHA76002, 77250, 77263, 77289, 77290,

77283

b

b

a

X

Mason, 1985

Score, King, et al., 1982; Schultz, 1985

Delaney et al., 1984

Delaney and Prinz, Chapter 8

Delaney et al., 1984; Delaney and Prinz, Chapter 8

Delaney et al., 1984;

Delaney and Prinz, Chapter 8

Mason et al., Chapter 6

Mason et al., Chapter 6

Mason et al., Chapter 6

Mason et al., Chapter 6

Delaney, 1985; Mason et al., Chapter 6

MacPherson, 1985b; Mason et al., Chapter 6

B. Mason, pers. communication

Score et al., 1981; Score, King, et al., 1982; Berkley

and Jones, 1982

Mason, 1984b

Mason, 1983a,b; Hewins, 1984

Clarke and Mason, 1982

Clarke et al., 1980

Malvinetal., 1984

Clarke, 1982

McSween, Chapter 9

Mason, 1983a; McSween, Chapter 9

Score, King, et al., 1982

MacPherson, 1985a,b

Scott, 1984b; Wieler et al., 1985

Mason, 1985

McKinley and Keil, 1984;

Wieler et al., 1985; this work

Mason, 1985
NUMBER 28 105

TABLE 13-1.—Continued.

Pair

number Specimens

Confidence

level References

H4 CHONDRITES

8.1 ALHA77004, 77190-77192, 77208, 77223- b

77226,77232, 77233

77221 c

8.2 ALHA77009, 81022 c

78084 x

8.3

8.4

8.5

8.6

ALHA78193, 78196, 78223

ALHA80106, 80121, 80128, 80131

ALHA81041, 81043-81052

RKPA80237, 80267

80232

H5 CHONDRITES

9.1

9.2

9.3

9.4

9.5

9.6

9.7

9.8

9.9

9.10

9.11

ALHA77014, 77264

ALHA77021, 77025, 77061, 77062, 77064,

77071, 77074, 77086, 77088, 77102

ALHA77118, 77119, 77124

ALHA78209, 78221, 78225, 78227, 78233

ALHA79031,79032

ALHA80111, 80124, 80127, 80129, 80132

RKPA80217, 80218

RKPA 80220, 80223

RKPA 80250, 80251

TIL82412, 82413

TIL82414, 82415

H6 CHONDRITES

10.1

10.2

10.3

10.4

10.5

10.6

10.7

10.8

10.9

11.1

11.2

11.3

ALHA77144, 77148

ALHA77271,77288

ALHA78211, 78213, 78215, 78229, 78231

ALHA80122, 80126, 80130

ALHA81035, 81038, 81103, 81112

MBRA76001,76002

RKPA80203, 80206, 80208, 80211, 80213,

80214, 80221, 80254, 80255, 80265,

80266

80231, 80262

EET82610,82615

PCA 82526, 82527

ALHA77011, 77015, 77031, 77033, 77034,

77036, 77043, 77047, 77049, 77050,

77052, 77115, 77140, 77160, 77163-

77167, 77170, 77175, 77178, 77185

77211, 77214, 77241, 77244, 77249,

77260, 77303, 78013, 78015, 78017,

78037, 78038, 78041, 78162, 78170,

78176, 78180, 78186, 78188, 78235,

78236, 78238, 78239, 78243, 79001,

79045, 80133, 81025, 81030-81032,

81053, 81060, 81061, 81065, 81066,

81069, 81085,81087, 81121, 81145,

81156, 81162, 81190, 81191, 81214,

81229, 81243, 81259, 81272, 81280,

81292, 81299

ALHA77215-77217, 77252

RKPA79OO8, 80207

b

c

c

b

X

c

c

X

c

b

b

c

c

c

c

c

c

c

a

b

c

c

a

b

c

c

c

a

a

X

Cassidy, 1980

Scott, 1984b

Score et al., 1984; Mason, 1983a

Scott, 1984b; Sarafin et al., 1985

Anonymous, 1981

Mason and Clarke, 1982

Score, 1983; Mason, 1983b

Mason and Clarke, 1982

Scott, 1984b

Cassidy, 1980

Cassidy, 1980;

Score etal., 1981

Cassidy, 1980

Anonymous, 1981

Score etal., 1981

Mason and Clarke, 1982; Vogt et al., 1985

Score, Schwarz, et al., 1982

Score, Schwarz, et al., 1982

Score, Schwarz, et al., 1982

Mason, 1984b

Mason, 1984b

Cassidy, 1980

Cassidy, 1980; Scott, 1984b

Anonymous, 1981

Mason and Clarke, 1982

Mason, 1983a,b; Anonymous, 1984

Weber and Schultz, 1980

Mason and Clarke, 1982

Scott, 1984b

Mason, 1984b

Mason, 1984b

McKinley et al., 1981; Scott, 1984b, this work;

Nishiizumi et al., 1983; Wieler et al., 1985

L4 CHONDRITES

12.1 RKPA80216, 80242

Score, 1980; Nautiyal et al, 1982

Wieler et al., 1985; this work

Score, Schwarz, et al., 1982
106 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 13-1.—Continued.

Pair

number Specimens

L5 CHONDRITES

13.1

13.2

13.3

ALHA81018, 81023

81017

PCA82504, 82505

RKPA80209, 80228, 80268

L6 CHONDRITES

14.1

14.2

14.3

14.4

14.5

14.6

14.7

14.8

14.9

14.10

14.11

14.12

ALHA76003, 76007

ALHA77001, 77292, 77293, 77296, 77297

77150,77180,77305

ALHA77272, 77273

77280, 77282

77231, 77269, 77270, 77277, 77281, 77284

ALHA78043, 78045

ALHA78103, 78105

78104, 78251

ALHA78112, 78114

ALHA78126, 78130, 78131

ALHA80101, 80103, 80105, 80107, 80108,

80110, 80112-80117, 80119, 80120,

80125,81017,81107,81262

ALHA81027-81029

BTNA78001, 78002

EET82605, 82606

RKPA78001, 78003

79001, 79002, 80202, 80219, 80225,

80252, 80261, 80264

LL3 CHONDRITES

15.1 ALHA76004, 81251

LL6 CHONDRITES

16.1 RKPA 80238, 80248

80222

Confidence

level

c

X

c

c

X

b

X

a

b

X

b

b

X

X

X

a

b

b

a

c

b

c

b

a

b

References

Mason, 1983a

Marvin, Chapter 14

Mason, 1984a

Mason and Clarke, 1982

Weber and Schultz, 1980

Cassidy, 1980

Anonymous, 1984; Scott 1984b

Cassidy, 1980

Goswami and Nishiizumi, 1983

Anonymous, 1984; Scott, 1984b

Score et al., 1981

Anonymous, 1984

Scott, 1984a

Score et al., 1981; Nishiizumi et al., 1983

Score et al., 1981; Scott, 1984b

Score, Schwarz, et al., 1982; Mason and Clarke, 1982

Marvin, Chapter 14

Mason, 1983a,b

Score et al., 1981; R. Score, pers. communication

Mason, 1984a

Score etal., 1981

Mason and Clarke, 1982; Scott, 1984b

Scott, 1984b; Wieler et al., 1985

Mason and Clarke, 1982

Sarafin and Herpers, 1983; Signer et al., 1983

proportion among falls, 68% (Wasson, 1974). However, in two

recent lists (Antarctic Meteorite Newsletter, 7(2) and 8(1)), the

proportion is only 25%.

Another measure of the concentration of effort on the rarer

meteorites is the number of proposed pairings of specimens

collected in different years. For the types 4-6 ordinary

chondrites in Table 13-1, only three of 43 pairing groups

contain specimens found in different years. However, for the

remaining meteorites, the corresponding figure is 13 out of 23

pairing groups. It is likely that most of the paired specimens

among type 3 chondrites (Scott, 1984a), polymict eucrites

(Delaney and Prinz, 1984), and other rarer meteorite types

have been identified. By contrast, it is certain that for types

4-6 ordinary chondrites, most of the paired specimens have

not been recognized.

Justifiably, no attempts have been made to identify paired

specimens among the 120 ALHA77- and 21 ALHA78- small

specimens of types 4-6 ordinary chondrites that were classified

by McKinley and Keil (1984) and by SJ.B. Reed and S.O.

Agrell (Antarctic Meteorite Newsletter 7(1), 1984).

To illustrate the importance of identifying paired specimens,

it is noted that petrologic descriptions of what are very

probably a set of paired L3 chondrites have been published

under various meteorite names: ALH-77015 (Nagahara, 1981;

Fujimake et al., 1981), ALH-77294 (Kimura, 1983), and

ALHA77011 (McKinley et al., 1981). The Nomenclature

Committee of the Meteoriu'cal Society recommends that the

lowest specimen number be adopted as the meteorite name

(Graham, 1980). However, in some cases the number of the

largest or best-distributed specimen may be a more appropriate

meteorite name. To distinguish specimen and meteorite names,

it may be useful to italicize the latter. Since no two Antarctic

specimens can be paired with complete certainty unless they

fit together like pieces of a jigsaw puzzle, it is important that

specimen numbers of analyzed paired samples should be

published, in addition to the meteorite name.
NUMBER 28 107

TABLE 13-2.—Numerical list of meteorite specimens that have been paired and the confidence level of these

pairings (confidence level: a = high; b = medium, c = low; x = unpaired or highly uncertain pairing).

Specimen

number

ALHA

76002

76003

76004

76005

76007

77001

77003

77004

77009

77011

77014

77015

77021

77025

77031

77033

77034

77036

77043

77047

77049

77050

77052

77061

77062

77064

77071

77074

77081

77086

77088

77102

77115

77118

77119

77124

77140

77144

77148

77150

77156

77160

77163-77167

77170

77175

77178

77180

77185

77190-77192

77208

77211

77214

77215-77217

77219

77221

77223-77226

77231

Pair

number

5.1

14.1

15.1

2.1

14.1

14.2

6.3

8.1

8.2

11.1

9.1

11.1

9.2

9.2

11.1

11.1

11.1

11.1

11.1

11.1

11.1

11.1

11.1

9.2

9.2

9.2

9.2

9.2

1.1

9.2

9.2

9.2

11.1

9.3

9.3

9.3

11.1

10.1

10.1

14.2

7.1

11.1

11.1

11.1

11.1

11.1

14.2

11.1

8.1

8.1

11.1

11.1

11.2

4.1

8.1

8.1

14.3

Confidence

level

a

X

b

a

X

b

X

b

c

a

c

a

c

c

a

a

a

a

a

a

a

a

a

c

c

c

c

c

a

c

c

X

a

c

c

c

a

c

c

X

a

a

a

a

a

a

X

a

b

b

a

a

a

b

c

b

X

Specimen

number

ALHA (continued)

77232

77233

77241

77244

77249

77250

77252

77260

77263

77264

77269

77270

1121 \

11212

77273

77277

77280

77281

77282

77283

77284

77288

77289

77290

77292

77293

77295

77296

77297

77302

77303

77305

77306

78013

78015

78017

78019

78037

78038

78040

78041

78043

78045

78084

78103

78104

78105

78112

78114

78126

78130

78131

78132

78158

78162

78165

78170

Pair

number

8.1

8.1

11.1

11.1

11.1

5.1

11.2

11.1

5.1

9.1

14.3

14.3

10.2

14.3

14.3

14.3

14.3

14.3

14.3

5.1

14.3

10.2

5.1

5.1

14.2

14.2

7.1

14.2

14.2

2.1

11.1

14.2

6.1

11.1

11.1

11.1

3.4

11.1

11.1

2.1

11.1

14.4

14.4

8.2

14.5

14.5

14.5

14.6

14.6

14.7

14.7

14.7

2.1

2.1

11.1

2.1

11.1

Confidence

level

b

b

a

a

a

a

a

a

a

c

X

X

a

a

a

X

b

X

b

X

X

a

a

a

b

b

a

b

b

a

a

X

X

a

a

a

c

a

a

a

a

b

b

X

b

X

b

X

X

X

X

X

a

a

a

a

a
108 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 13-2.—Continued.

Specimen

number

ALHA (continued)

78176

78180

78186

78188

78193

78196

78209

78211

78213

78215

78221

78223

78225

78227

78229

78231

78233

78235

78236

78238

78239

78243

78251

78261

78262

79001

79017

79031

79032

79045

80101

80102

80103

80105

80106

80107

80108

80110

80111

80112-80117

80119

80120

80121

80122

80124

80125

80126

80127

80128

80129

80130

80131

80132

80133

81001

81002

81003

Pair

number

11.1

11.1

11.1

11.1

8.3

8.3

9.4

10.3

10.3

10.3

9.4

8.3

9.4

9.4

10.3

10.3

9.4

11.1

11.1

11.1

11.1

11.1

14.5

6.1

3.4

11.1

2.1

9.5

9.5

11.1

14.8

2.1

14.8

14.8

8.4

14.8

14.8

14.8

9.6

14.8

14.8

14.8

8.4

10.4

9.6

14.8

10.4

9.6

8.4

9.6

10.4

8.4

9.6

11.1

2.1

6.1

6.4

Confidence

level

a

a

a

a

b

b

b

b

b

b

b

b

b

b

b

b

b

a

a

a

a

a

X

c

c

a

a

b

b

a

b

b

b

b

c

b

b

b

c

b

b

b

c

c

c

b

c

c

c

c

c

c

c

a

b

b

c

Specimen

number

ALHA (continued)

81004

81006-81008

81009

81010

81012

81017

81018

81021

81022

81023

81025

81027-81029

81030-81032

81035

81038

81041

81043-81052

81053

81059

81060

81061

81065

81066

81069

81085

81087

81098

81103

81107

81112

81121

81145

81156

81162

81189

81190

81191

81214

81229

81243

81251

81258

81259

81260

81261

81262

81272

81280

81292

81299

81315

82100

82101

82106

82130

82131

83009

Pair

number

6.1

2.1

2.1

2.1

2.1

13.1

14.8

13.1

7.2

8.2

13.1

11.1

14.9

11.1

10.5

10.5

8.5

8.5

11.1

4.1

11.1

11.1

11.1

11.1

11.1

11.1

11.1

4.1

10.5

14.8

10.5

11.1

11.1

11.1

11.1

7.1

11.1

11.1

11.1

11.1

11.1

15.1

6.4

11.1

7.2

1.1

14.8

11.1

11.1

11.1

11.1

1.1

6.1

6.3

3.5

3.5

6.1

3.1

Confidence

level

b

b

a

b

b

X

b

c

c

c

c

a

b

a

c

c

c

c

a

b

a

a

a

a

a

a

a

b

c

b

c

a

a

a

a

X

a

a

a

a

a

b

c

a

c

a

b

a

a

a

a

a

b

X

a

a

c

a
NUMBER 28 109

TABLE 13-2.—Continued.

Specimen

number

ALHA (continued)

83015

83016

83100

83102

84007

84008

84011

84029-84032

84034

84042

84044

BTNA

78001

78002

DRPA

A78001-78016

EETA

79004-79006

79011

82600

82605

82606

82610

82615

83227-83229

83231

83232

83234

83235

83246

83247

83251

83283

MBRA

76001

76002

PCA

82504

82505

82526

82527

RKPA

78001

78003

Pair

number

3.1

6.1

6.2

6.2

3.2

3.2

3.2

6.2

6.2

6.2

6.2

14.10

14.10

5.2

2.2

2.2

2.2

14.11

14.11

10.8

10.8

2.2

2.2

2.2

2.2

2.2

3.3

3.3

2.2

2.2

10.6

10.6

13.2

13.2

10.9

10.9

14.12

14.12

Confidence

level

a

c

b

b

b

b

b

b

b

b

b

a

a

a

b

b

b

c

c

c

c

b

b

b

b

b

X

X

b

b

a

a

c

c

c

c

b

b

Specimen

number

RKPA (continued)

79001

79002

79008

79015

80202

80203

80206

80207

80208

80209

80211

80213

80214

80216

80217

80218

80219

80220

80221

80222

80223

80225

80228

80229

80231

80232

80237

80238

80242

80246

80248

80250

80251

80252

80254

80255

80258

80261

80262

80263

80264

80265

80266

80267

80268

TIL

82412

82413

82414

82415

Pair

number

14.12

14.12

11.3

4.2

14.12

10.7

10.7

11.3

10.7

13.3

10.7

10.7

10.7

12.1

9.7

9.7

14.12

9.8

10.7

16.1

9.8

14.12

13.3

4.2

10.7

8.6

8.6

16.1

12.1

4.2

16.1

9.9

9.9

14.12

10.7

10.7

4.2

14.12

10.7

4.2

14.12

10.7

10.7

8.6

13.3

9.10

9.10

9.11

9.11

Confidence

level

c

c

X

b

c

b

b

X

b

c

b

b

b

b

c

c

c

c

b

b

c

c

c

b

c

X

b

a

b

b

a

c

c

c

b

b

b

c

c

b

c

b

b

b

c

c

c

c

c
110 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

Pairing Notes

Pair Number 2.2

There is some disagreement on the classification and pairing

of the 16 eucrites, polymict eucrites and howardites that have

been recovered from Elephant Moraine. On the basis of

pyroxene analyses, Mason et al. (this volume) believe that 15

specimens come from three different falls; EET83236 may be

unpaired. Delaney and Prinz (this volume) argue instead, from

their petrographic studies, that 14 of these 15 specimens belong

to two falls; they exclude EET83212 because the section

studied appeared atypical. Both pairing schemes are listed in

Table 13-1. EETA79005, 79006 and 82600, which are paired

by both groups, have similar terrestrial and cosmic-ray

exposure ages of 0.17-0.19 and 26-28 million years,

confirming their pairing (Schultz, 1985). Schultz believes, as

do Delaney and Prinz, and Mason et al. that EETA79004 is

not paired with these three; its terrestrial and exposure ages are

0.25 and 22 million years.

Pair Number 7.1

Concentrations of spallogenic noble gases in two EH3/4

chondrites, ALHA77156 and ALHA77295, are very similar

(Weiler et al., 1985), confirming their pairing on petrographic

grounds by McKinley and Keil (1984). Since they were found

18 km apart, this additional evidence for pairing is valuable.

Petrologic studies by Prinz et al. (1985) show that ALHA81189

is a highly unequilibrated enstatite chondrite like 77156.

However, their modal analyses suggest that 81189 has a much

higher abundance of olivine (8% cf. 2% in 77156) and is not

paired.

Pair Number 11.1

Confirmation that ALHA77047, 78015, 81030-81032, and

81121 are paired with many other L3 specimens that contain

abundant graphite-magnetite aggregates is provided by their

concentrations of spallogenic and trapped noble gases (Weiler

et al., 1985). These authors also confirm that ALHA81024 is

not part of this meteorite shower, even though it also contains

abundant graphite-magnetite aggregates (Scott, 1984b). There

are seven other unpaired L3 specimens from Allan Hills in

United States collections: 77013, 77176, 77197, 78046, 78119,

78133, and 83010. Wieler et al. (1985) have analyzed all but

78046, 78119, and 83010, and their data support this

conclusion.

Pair Number 11.3

RKPA79008 and 80207, which were originally classified

as L3 chondrites (Score et al., 1982b, 1984), contain similar

concentrations of spallogenic

 21Ne, and concentrations of solar

wind noble gases that are within a factor of two. Since only

two other Antarctic and six non-Antarctic L chondrites are

known to contain solar wind gases, the suggestion of Wieler

et al. (1985) that these two Reckling Peak specimens are paired

would appear very likely. However, RKPA80207 is probably

an H3 chondrite, as the great majority of its olivine grains

have compositions appropriate to equilibrated H chondrites

(Scott, 1984a). In RKPA79008, by contrast, most olivines

have compositions like those of equilbrated L chondrites. Since

chondrites having materials with the compositions of both

equilibrated H and L chondrites are not known, it is more likely

that these two specimens are not paired.

Pair Number 15.1

The presence of rather similar concentrations of spallogenic

and trapped noble gases in the LL3 chondrites, ALHA76004

and 81251, supports their pairing (Wieler et al., 1985).

Although petrographically similar, they have very different

degrees of weathering, unlike other paired specimens (Scott,

1984b).

ACKNOWLEDGMENTS.—I thank B. Mason, H.Y. McSween,

Jr., R.A. Score, P. Signer, R. Wieler, and other members of the

Meteorite Working Group for their helpful assistance. This

work was partly supported by NASA grant NAG-9-30 to K.

Keil.

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Score, R., CM. Schwarz, T.V.V. King, B. Mason, D.D. Bogard, and E.M.

Gabel

1981. Antarctic Meteorite Descriptions 1976-1977-1978-1979. Curatorial Branch Publication 54, JSC 17076. 144 pages. Houston:

Johnson Space Center.

Score, R., CM. Schwarz, and B. Mason

1984. Descriptions of Stony Meteorites. In U.B. Marvin and B. Mason,

editors, Field and Laboratory Investigations of Meteorites from

Victoria Land, Antarctica. Smithsonian Contributions to the Earth

Sciences, 26:23^17.

Score, R., CM. Schwarz, B. Mason, and D.D. Bogard

1982. Antarctic Meteorite Descriptions 1980. Curatorial Branch Publication 60, JSC 18170. 55 pages. Houston: Johnson Space Center.

Scott, E.R.D.

1984a. Classification, Metamorphism, and Brecciation of Type 3 Chondrites from Antarctica. In U.B. Marvin and B. Mason, editors. Field

and Laboratory Investigations of Meteorites from Victoria Land,

Antarctica. Smithsonian Contributions to the Earth Sciences,

26:73-94.

1984b. Pairing of Meteorites Found in Victoria Land, Antarctica. Memoirs

of the National Institute of Polar Research (Japan), special issue,

35:102-125.

Signer, P., H. Baur, Ph. Etique, and R. Wieler

1983. Light Noble Gases in 15 Meteorites. Meteoritics, 18:399.

Vogt, St., U. Herpers, R. Sarafin, P. Signer, R. Wieler, M. Suter, and W. Wolfli

1985. Cosmic Ray Records in Antarctic Meteorites. In Abstracts for

Workshop on Antarctic Meteorites, pages 55-57. Houston: Lunar

and Planetary Institute.

Wasson, J.T.

1974. Meteorites—Classification and Properties. 316 pages. Heidelberg:

Springer-Verlag.

Weber, H.W, and L. Schultz

1980. Noble Gases in Ten Stone Meteorites from Antarctica. Zeitschrift

fur Naturforschung, 35a:44—49.

Wieler, R., H. Baur, Th. Graf, and P. Signer

1985. He, Ne, and Ar in Antarctic Meteorites: Solar Noble Gases in an

Enstatite Chondrite. In Lunar and Planetary Science XVI, pages

902-903. Houston: Lunar and Planetary Institute.

Yanai, K.

1982. Antarctic Meteorite Distribution Map of Allan Hills Victoria Land,

Antarctica—Allan Hills-76, -77 and -78 Meteorites. Tokyo:

National Institute of Polar Research.

1984. Locality Map Series of Antarctic Meteorites, Sheet 1, Allan Hills:

Explanatory Text of Local Map of Allan Hills-76, Allan Hills-77

and Allan Hills-78 Meteorites. Tokyo: National Institute of Polar

Research.
14. Meteorite Distributions at the Allan Hills Main Icefield

and the Pairing Problem

Ursula B. Marvin

Paired meteorite specimens are fragments of a single body

that exploded during flight through the atmosphere and fell to

Earth as two or more pieces. All fragments, which may number

in the thousands, of the same body are cataloged as a single

meteorite. Observations in many parts of the world have shown

that fragments from a given meteorite shower fall over an

elliptical area in which the largest and heaviest specimens

travel farthest along the line of flight to the outer limit of a

so-called strewnfield. Outside Antarctica, specimens belonging

to the same class of meteorite found in a well-defined

strewnfield can be paired with confidence. On the Antarctic

stranding surfaces, however, strewnfields emerged from depth

will be compressed and deformed to some degree and their

specimens mixed with those from other falls. The extent to

which distribution patterns can aid in pairing specimens of a

given meteorite class on the Antarctic icefields has not

previously been investigated.

My approach to this problem was to plot the locations of

meteorite fragments on a composite map representing six

seasons of collecting on the Allan Hills Main Icefield. I also

examined thin sections of tentatively paired specimens and

combed the literature on pairing. I found that only on rare

occasions is pairing easy in Antarctica. When two or more

fragments fit together like pieces of a jigsaw puzzle, as was the

case with the pieces in Figure 14-1, they are paired in the field

and assigned the same specimen number. Specimens are

sometimes paired in the field if they look similar and lie within

a few meters of one another without actually fitting together.

In general, however, the pairing of Antarctic specimens is

fraught with uncertainty. Distribution patterns facilitate pairing

mainly by indicating which groups of specimens should be

scrutinized for similarities in petrography, trace element

compositions, solar flare tracks, or other diagnostic features.

Frequently, such scrutiny indicates that specimens found lying

side by side are not members of the same shower. In at least

one case, however, the opposite proved true: the location of a

Ursula B. Marvin, Smithsonian Astrophysical Observatory, 60 Garden

Street, Cambridge, Massachusetts 02138.

specimen led to its reclassification as a member of a paired

group.

Field Maps

Perhaps the main difficulty in mapping specimen distribution patterns on the Allan Hills Main Icefield, is the lack of a

single, accurate base map. For the present study, I compiled

distributions from two maps. The first map was published by

Yanai (1982) with an explanatory text by Yanai (1984). Yanai

plotted approximate specimen locations, from field notes made

during the 1976-1977, 1977-1978, and 1978-1979 seasons,

on a base prepared from an enlarged satellite photograph of the

Allan Hills region. The second base map was an unpublished

chart, 1.6 meters long with a scale of about 1:8000, prepared

by John O. Annexstad and John W. Schutt to show specimen

locations of the 1979-1980, 1980-1981, and 1981-1982

seasons. They measured angular directions from each specimen

to flags in the geodetic network described by Annexstad and

Annexstad (Chapter 4), and measured distances on snowmobile

odometers. Together, the maps of Yanai and of Annexstad and

Schutt show the locations of about 900 meteorites on the Main

Icefield, a number fully adequate for testing the usefulness of

distribution patterns.

Unfortunately, the two maps have no common reference

point that can be used to superimpose them precisely. Yanai

marked latitudes and longitudes on his map but Annexstad and

Schutt did not. The latter authors based their map on a

coordinate system measured in meters from geodetic network

Stations 1 and 2, which were anchored in bedrock and tied by

triangulation to peaks in the Allan Hills. They used a satellite

photograph, different from Yanai's, to draw in the outlines of

the Allan Hills. Both maps show distortion due to the

obliqueness of the satellite photographs. After photocopying

the two maps to the same scale, I tested several methods of

superimposing them and selected the one that produced the

least distortion in the southern and central part of the Main

Icefield. These regions are shown in Figures 14-2 to 14-6. In

those figures on which all specimens are plotted from either

113
114 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 14-1.—Meteorite fragments paired in the field. The two pieces of Allan Hills 81029, a 153 gram L6

chondrite, fitted tightly together along a fractured surface.

Yanai's map or the one by Annexstad and Schutt, the location

of each specimen is probably accurate to within a radius of

about 100 meters. On those with specimen locations taken from

both maps the uncertainty may well involve a radius of up to

2 kilometers. Even with errors of that magnitude, however, it

is possible in most cases to see which meteorite fragments

occur in clusters and which lie far apart. Figures 14-2 to 14-6

illustrate the distribution patterns of eucrites, ureilites, irons,

L3, and L6 chondrites on the Main Icefield, and Figure 14-7

shows that of three mesosiderites found on the Near Western

Icefield. Various proposed pairing schemes are indicated and

referenced.

Meteorite Distributions

EUCRITES

Beginning in the 1976-1977 season with the discovery of

ALHA76005, a 1.4 kg polymict eucrite, a total of 16 eucrite

specimens were collected within an area of only about 3.5 x

4.5 kilometers on the Main Icefield (Figure 14-2). Their

distribution suggests that all of these fragments belong to the

same fall. Some petrologic studies tend to support this

interpretation. Delaney, Takeda, and Prinz (1983) tentatively

paired 12 of the 16 specimens as polymict eucrites (containing

90% or more of eucritic components) belonging to a group

they designated as Allan Hills I. Their second group, Allan

Hills II, consisted solely of 78006, a howardite in which no

single component makes up 90% j)f the breccia. Further

petrographic analyses led Delaney, Prinz, and Stokes (1984)

to designate a third group, Allan Hills III, made up of 81006,

81007, and 81008, specimens they found to contain less

feldspar and more pyroxene than they observed in the other

members of Group I, and lithic clasts of an apparent pigeonite

cumulate not observed in any other eucrites.

Score, Schwarz, and Mason (1984) listed 12 of the 16

specimens as polymict eucrites and paired them on the basis

of external appearance and thin section petrography. They

tentatively designated 81009 and 81012 as a separate pair

because they differ from the other 12 specimens in the range
NUMBER 28 115

EUCRITES \

78006

 u

\

A

\

'S »

78158

 plj s 9 6 othe r

178165** Meteorites

\ at this site

\

\

\

.--#- \ 76°42

81010 \

i»\

8IOO7.-iV __b 81008 j»V

..8OIO2'«eioO6

o

78132

79017

•O

N \

's \

eiooi ^ \

0.5 I kn

J_J |

KEY;

O Meteorites collected 1976-1978 (from YANAI MAP)

• Meteorites collected 1979-1981 (from ANNEXSTAD-SCHUTT MAP)

ICE- FIRN BOUNDARY (from YANAI MAP)

ICE-FIRN BOUNDARY (from ANNEXSTAD-SCHUTT MAP)

XJ- " EAST-FACING SLOPE OF MONOCLINE (ANNEXSTAD-SCHUTT MAP)

:

".'...'.'.'• PROPOSED PAIRINGS

® ® METEORITES SINGLED OUT AS UNPAIRED

FIGURE 14-2.—The distribution of 16 eucrite specimens and one howardite

(78006) on the Main Icefield. Areas outlined by dots include tentatively paired

specimens; the shapes of the areas are of no other significance. Pair "a" was

proposed by Score, Schwarz, and Mason (1984); pair "b" was proposed by

Delaney, Prinz, and Stokes (1984), but later incorporated by Delaney, Prinz,

and Takeda (1984) into Allan Hills Group I, which includes all specimens on

this map except 81001, the felty glass, and 78006, the howardite. Many

specimens belonging to other meteorite classes were also found in this area.

For example, the arrow at upper right indicates a site where two eucrites and

96 other stones were collected.

and distribution of their pyroxene compositions. The same

authors listed 81001 as anomalous, and 81011 (the location of

which was not mapped) as a eucritic breccia. They described

the anomalous stone, 81001, as consisting of smoky gray glass

crowded with felty pyroxene prisms (Score, Schwarz, and

Mason, 1984:44, and their figure 49a). The bulk composition

resembles that of an average eucrite, but no other eucrite has

such a texture. However, small clasts of similar material are

found within some polymict eucrites. The other unusual stone,

81011, has eucritic clasts up to 1 cm long embedded in a matrix

of dark glass and finely crushed plagioclase and pyroxene. The

stone looks polymict, but uniform compositions of the

plagioclase and pyroxene suggest that it is monomict.

After reviewing the evidence, Delaney, Prinz, and Takeda

(1984) concluded that all but two of the eucrites at the Allan

Hills probably belong to Group I, a heterogeneous suite in

which they included 81009 and 81012 and to which they

reassigned 81006, 81007, and 81008. They excluded only the

78019

ICE

\°'

'.

/

i

\

\

•

•

•

*

*

77257Q

i > 11 i i i

1 km

LJ

CO

0

m

FIRN

\ ^

\

\

\

\

*

UREILITES

\

\ 76°42

\

\

\

\

\

)

78262\O * \

\

\

\

\

\

\

\

\

81101^ \

s

\

FIGURE 14-3.—Locations of four Allan Hills ureilites. The two closest stones,

77257 and 78262, have not been paired, but 78019 and 78262 were paired by

Score et al. (1981). This pairing is disputed by Berkley and Jones (1982). If it

is invalid, all four specimens represent separate falls.

glassy stone, 81001, and the breccia, 81011. Possibly even

81001 should be paired with the main group; its glassy texture

may simply represent the chilled margin of a flow or layered

body from which the other eucrites originally crystallized.

UREILITES

Four ureilite specimens were found on the Main Icefield

by the end of the 1981-1982 season. Without knowledge of

their field occurrence, Score et al. (1981) designated 77257 and

78262 as separate falls and paired 78262 with 78019 on the

basis of similar external appearance, textures, and olivine and
116 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

RONS O77250

ICE / FIRN

/

:O

77289

77263

:O 77283

77290

o

\

"*•• °>6002

\ 76°45/S

\

\

\

\

O78252 0.5 I I

i.i. l I

N

FIGURE 14-4.—Locations of seven iron meteorite specimens. All except 78252

were paired in the field by Cassidy (1980) and later proved to be coarse

octahedrites of group IA. Clarke et al. (1980) paired the five irons within the

dotted area but separated out 77283 because, although it belongs to the same

chemical group, it contains clumps of shock-produced diamond and lonsdaleite.

ALHA78252 is a group IVA iron.

pyroxene compositions. Figure 14-3 shows that the first two

were found only 1.5 kilometers apart, although in different

seasons, and the paired stones were found nearly 5.8 kilometers

apart in the same season. Pair 78262 and 78019 is listed in

Appendix C, but Berkley and Jones (1982) disputed its validity,

arguing that the olivines and pyroxenes in the two stones differ

slightly but consistently, and that diamond occurs in 78262

but not in 78019. Petrographic differences between the other

stones indicate that, if these two are not paired, then all four

ureilites represent individual falls—a surprising situation for

such unusual meteorites on a small area of the Icefield, when

only about 20 other ureilites have been found throughout the

world. Field distribution was of no aid in this case where, if

any stones are paired, they are not the two found closest

together.

/

£ o7 7'

7^ X

(g)77l76

X °77I78

X

\

r\ ^

Vi>8IO24 \

\

X

ICE / | FIRN

(i

77197® \ f

§

77031 \j

78015 /.

, - 7 71-17/1, A

L3 CHONDRITES

78015 ,,

77I7O>"'^77034 | \ f-*

77043O o I \ / /

77033 \ V.S

I \78I88

I O+

X °V \

\

\

77036 N

• 96 other

Meteorites

at this site

O 77115 A

/

2 #

81145*

Q'77140 \

' .81069 \

80133 \v._8IO87

77047OO 77049 XI8I085

a

77050

8I065/66*

• •

81053

76°42'S

^ 8

• 81156

?

77052

77214

O 77241

^78038i'\ \

77I66O

79022^ *79045 \

7400.« 8 f 2 | \ «

77165?

„,„ 77160V

772I \ 7727

4

7

9

8O5

"° ^

77260«\... 77QII ~ (9J\ / 0 O

77303- O 77211

77244*

77215 •/-...9=77252 /

77216 /

£77015

/

FIGURE 14-5.—The distribution of L3 chondrites on the central and southern

portion of the Main Icefield. Other L3 specimens lay farther north, off this

map. Unpaired specimens are indicated by extra rings; all others are paired

(and designated as the 77011 shower) except for the four specimens lying

within the dotted area at lower right, which differ from the others

petrographically (Score, 1980; Score et al., 1981) and in containing solar flare

tracks (Nautiyal et al., 1982).

octahedrites belonging to chemical group IA, but Clarke et al.

(1980), paired only the five specimens outlined in Figure 14-5,

on the basis of identical textures and compositions. The

adjacent unpaired specimen, 77283, contains masses of minute

shock-produced diamonds admixed with lonsdaleite. The only

other iron meteorite known to contain diamonds is Canyon

Diablo, a huge body that impacted northern Arizona with

sufficient energy to excavate a crater 1.4 kilometers in

diameter. The Allan Hills iron, in contrast, is a 10-gram

specimen with a thin surficial, heat-altered zone, which shows

that it entered the atmosphere as a small body that would have

made a soft landing. The diamonds must have formed during

a preterrestrial collision in space.

The seventh specimen, 78252, is a group IVA iron. The

distribution of these iron meteorites suggested a pairing scheme

close to, but not identical with, the one indicated by

compositions and textures.

IRONS

Seven specimens of irons were found within the 1.5 x 4.5

km area shown in Figure 14-4. Cassidy (1980) tentatively

paired six of them (all except 78252, which lay farthest south)

on the basis of their field locations. All of the six are coarse

L3 CHONDRITES

Seventy-five L3 chondrite specimens (56 mapped finds and

19 unmapped pebbles) were collected within a 6 x 3 km ellipse

on the Main Icefield. The larger fragments were clustered near

the southern end of the ellipse and smaller pieces lay at the
NUMBER 28

L6 CHONDRITES

O76003

O76007

O78I30

^ O76009

/

/

/

/

/

1

V

\

\

\

\

\

\

\

\

78105 v.

•••9.-' ^

78103

0.5 1 km

1 i i i i 1 1

78050

/

78043-. / 7 7

d »-;°-:/

780459-;" ° x °

ICE / FIRN

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1

284

Q

O77270

781271

X

77269 i

78042Q

78104-

77277 o

• o ••

76001 '•

- —

UJ

~b

CMI59

C

78II4O

77155

0

•••..°7728!

c—•'•.

78106 o''". ' '

(

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18 SPECIMENS

•«— INS'ET A

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\

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'•- . O-. ':

b ^41.'.:Q: :'

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77273

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\

\

\ /

V /

L6

INSET A

1

80107* *8OIO8

.80125

• 80119

# 80ll 4

• 80113

80110

^80120

8I262 # *8OII6 •81107

— ^ 81017* •SO" 7

• 80115

80112 « • 80103

8OIOI # # 8OIO5

100 M

117

FIGURE 14-6.—The distribution of 44 L6 chondrite specimens that were collected on the central and southern

portion of the Main Icefield. Several (but not all) of the proposed pairing schemes are shown. Pair "a" consists

of four specimens, 77231, 77273, 77272, and 77280, tentatively paired in the field by Cassidy. All were rather

large specimens lying near one another. Pair "b" was separated out on the basis of similar petrography and

concentrations of cosmogenic nuclides by Nishiizumi (1984). Specimens 77231 and 77280 differ in nuclide

concentrations and cannot be paired with 77272 and 77273; however, Goswami and Nishiizumi (1983) proposed

pair "c," 77280 and 77282. Pair "d" was proposed by Score et al. (1981) on petrographic similarities. Pair "e,"

78103 and 78105, were found close together in a remote location and they have similar concentrations of ^Al

(Evans, Reeves, and Rancitelli, 1982). Inset A shows the location of 18 specimens collected in 1980 and 1981

beyond the southern edge of the Main Icefield. All were classified on petrographic evidence as L6 chondrites,

except 81017 (arrow), which was first classed as an L5 and later reclassified as an L6.

ice-firn border at the northern end. This size distribution

suggested a strewnfield created by a southbound fireball;

however, as noted by Scott (1984) it is more likely that the

small fragments were blown to the northern edge of the Icefield

by the powerful katabatic winds that course down the surface

of the ice sheet from the southern reaches of the polar plateau.

The great majority of these L3 chondrites, large and small,

contain distinctive graphite-magnetite aggregates and so were

paired by McKinley et al. (1981). However, within a group of

nine relatively large specimens lying within an area only 500

meters across, four were shown to belong to a separate fall on

the basis of petrography (Score, 1980), and the presence of

solar flare tracks (Nautiyal, et al., 1982). Specimen distributions would never suggest the existence of this separate fall

(Figure 14-5). Several distinctive, unpaired L3 specimens lie

scattered amid the large group.

L6 CHONDRITES

Eighty-five L6 chondrites were collected during the first six

seasons on the Main Icefield. Numerous pairing schemes have

been proposed and almost all of them are disputed. The map
118 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

/ / /

/ ''• .^.81059

I i i i i I

500 M

81098 \

\

\

UJ

"in

S

MESOSIDERITES

Near Western Icefield

\

^ 76°44'S

\

\

\

\

\

\

\

77219 (^"\

FIGURE 14-7.—The only mesosiderites found in the Allan Hills region lay

within 2.25 kilometers of each other on the Near Western Icefield. 81098

consisted of two adjacent pieces that were paired in the field; 81059 was added

to the pair after laboratory examination. Although mesosiderites tend to be

markedly inhomogeneous, 77219 is regarded as a separate fall.

in Figure l4-6a, which includes only the area toward the

southern end of the field, shows find locations of 44 specimens

and five of the proposed pairings. The four specimens (77272,

77273, 77231, and 77280) at the southeastern part of the field

were tentatively paired in the field by Cassidy (1980). Six

others (77282, 77269, 77270, 77277, 77281, and 77284) were

paired with these four in the Antarctic Meteorite Newsletter,

7(1) (1984). Two specimens (77272 and 77273) of Cassidy's

original four are still accepted as a pair, but differences in

 53Mn

concentrations and cosmic-ray track densities, measured by

Goswami and Nishiizumi (1983), indicate that 77273 and

77280 cannot be paired with each other even though they were

found only 200 meters apart. Without being aware of the field

distribution, the same authors using the same criteria paired

77280 with 77282, which were separated by a distance of

nearly three kilometers. This leaves one of Cassidy's original

four, 77231, unpaired. Two other specimens, 78043 and 78045,

were paired on petrographic evidence by Score et al. (1981),

and 78103 and 78105, which were were found only about 100

meters apart in a remote part of the field, were paired in the

Antarctic Meteorite Newsletter (1984). For evaluations of other

proposed pairings, see Scott (1984, and Chapter 13).

At the southern extremity of the map, separated from the

Main Icefield by a wide band of snow, a group of specimens

occupied an area about 500 meters long and 200 meters wide

(see Inset A, Figure 14-6). Fifteen specimens were collected

there in 1980 and identified as L6 chondrites by Score et al.

(1982), who, with no knowledge of their field occurrence,

paired them on the basis of identical textures, mineralogy, and

degrees of weathering. Three more specimens were picked up

in 1981. When thin sections of these were studied, again

without knowledge of their field locations, 81107 and 81262

were classed as L6, but 81017 was classed as an L5 chondrite.

The anomalous presence of an L5 in this tight cluster of L6

specimens, prompted me to request a reexamination of the thin

section of 81017. Mason (personal communication) complied,

and shortly afterward reported that he had originally classed

the specimen as an L5 because he had noted no plagioclase in

the section. On the second examination he found traces of

plagioclase and, as the difference between classes 5 and 6 is

often very uncertain, he reclassified 81017 as an L6 chondrite

belonging with the rest of the group. L6 chondrites are actually

so much alike that a case might be made for pairing these 18

specimens with the main group lying farther north. However,

the tightly clustered field distribution provides strong evidence

of a separate fall of L6 fragments.

MESOSIDERITES

Three mesosiderite specimens have been found in the Allan

Hills region, all of them on the Near Western Icefield (Figure

14-7), which lies about 15 kilometers from the Main Icefield.

Specimen 77219 was found during a brief helicopter reconaissance in the 1977 season; the other two, 81059 and 81098,

were collected on snowmobile traverses in the 1981 season.

Specimen 81098 actually consisted of two fragments that were

paired in the field. Clarke (1984) suggested pairing 81059 and

81098 on the basis of their mineralogy, texture, and degree of

weathering, but he regarded 77219 as a separate fall. Inasmuch

as mesosiderites are among the rarest of meteorites (stony-irons

of all types make up only 1.5% of falls), the occurrence of these

three specimens within 2.5 kilometers of each other at one end

of the small Near Western Icefield would suggest a common

source. Their distribution alone would not be sufficient for

pairing them, but analyses of their isotopic or trace element

content or particle track densities might yield conclusive

evidence for or against pairing.

Conclusions

This study shows that distribution patterns of specimens on

the Antarctic ice sheet can be a helpful guide to meteorite

pairings, but one that always must be used in conjunction with

other types of evidence. Laboratory examinations confirmed

the main outlines of field pairings for some of the seven

meteorite classes discussed herein, but produced numerous

surprises when adjacent specimens proved not to belong to the

same fall and widely separated ones showed strong evidence

that they did belong together. Meteorites that fall close together

are, in general, expected to remain close together while being

transported within a large ice sheet. Confusion begins when

they emerge from the ice and and are mixed with other

meteorites on stranding surfaces that are compressed against

mountain barriers by the persistent push of the oncoming sheet.

Furthermore, the powerful storm winds of Antarctica can send

specimens up to cobble size—and probably boulder size—

skittering across the ice to new locations, and drifts of snow
NUMBER 28 119

cover and uncover different groups of specimens from season

to season. Despite all the factors that disturb the orderly

patterns of strewnfields, specimen distributions are of sufficient

aid in pairing to make mapping worth the effort.

Since the 1982-1983 season, mapping techniques have been

speeded up and made more accurate by use of an infrared

distance measuring device to determine geodetic positions of

meteorite specimens relative to known points. There will be

no further need for painstaking attempts like this one to

superimpose maps in order to locate find sites. However, the

first six seasons at the Allan Hills Main Icefield yielded a

unique body of data that demanded analysis.

ACKNOWLEDGEMENTS.—I wish to thank John Annexstad

and John Schutt for kindly furnishing me with their map of

meteorite distributions on the Allan Hills Main Ice Field, and

Robbie Score and Ed Scott for critical readings of this

manuscript. This work was supported in part by NASA Grant

NAG 9-29 and in part by SAO allocation 86400040-P12P11-

4P50.

Literature Cited

Antarctic Meteorite Newsletter, 7(1), 1984.

Berkley, J.L., and J.H. Jones

1982. Primary Igneous Carbon in Ureilites: Petrological Implications.

Journal of Geophysical Research, 87 (supplement):A353-A364.

Cassidy, William A.

1980. list of Possible Pairings of ALHA77 Meteorites. In U.B. Marvin

and B. Mason, editors, Catalog of Antarctic Meteorites, 1977-1978.

Smithsonian Contributions to the Earth Sciences, 23:44-46.

Clarke, Roy S., Jr.,

1984. Descriptions of Iron Meteorites and Mesosiderites. In U.B. Marvin

and B. Mason, editors, Field and Laboratory Investigations of

Meteorites from Victoria Land, Antarctica. Smithsonian Contributions to the Earth Sciences, 26:49-53.

Clarke, R.S., Jr., E. Jarosewich, J.I. Goldstein, and P.A. Baedecker

1980. Antarctic Iron Meteorites from Allan Hills and Purgatory Peak.

Meteor itics, 15:273-274.

Delaney, J.S., M. Prinz, and C.P. Stokes

1984. The Allan Hills 81-series of Polymict Eucrites. In Lunar and

Planetary Science XV, pages 214-215. Houston: Lunar and

Planetary Institute.

Delaney, J.S., M. Prinz, and H. Takeda

1984. The Polymict Eucrites. Journal of Geophysical Research, 89

(supplement):C251-C288.

Delaney, J.S., H. Takeda, and M. Prinz

1983. Modal Comparison of Yamato and Allan Hills Polymict Eucrites.

Memoirs of the National Institute of Polar Research (Japan), special

issue, 30:206-223.

Evans, J.C., J.H. Reeves, and L.A. Rancitelli

1982. Aluminum-26 Survey of Victoria Land Meteorites. In U.B. Marvin

and B. Mason, editors, Smithsonian Contributions to the Earth

Sciences, 24:70-74.

Goswami, N.N., and K. Nishiizumi

1983. Cosmogenic Records in Antarctic Meteorites. Earth and Planetary

Science Letters, 64:1-8.

McKinley, S.G., E.R.D. Scott, GJ. Taylor, and K. Keil

1981. A Unique Type 3 Ordinary Chondrite Containing GraphiteMagnetite Aggregates—Allan Hills A77011. In Proceedings of the

Twelfth Lunar and Planetary Science Conference, pages 1039-1048.

New York: Pergamon Press.

Nautiyal, CM., J.T. Padia, M.N. Rao, T.R. Venkatesan, and J.N. Goswami

1982. Irradiation History of Antarctic Gas-Rich Meteorites. In Lunar and

Planetary Science XIII, pages 578-579. Houston: Lunar and

Planetary Institute.

Nishiizumi, K.

1984. Cosmic-ray Produced Nuclides in Victoria Land Meteorites. In

U.B. Marvin and B. Mason, editors, Smithsonian Contributions to

the Earth Sciences, 26:105-109.

Score, R.

1980. Allan Hills 77216: A Petrologic and Mineralogic Description.

[Abstract.] Meteoritics, 15:363.

Score, R., CM. Schwarz, T.V.V. King, B. Mason, D.D. Bogard, and E. M.

Gabel

1981. Antarctic Meteorite Descriptions 1976-1977-1978-1979. Curatorial Branch Publication, 54, JSC 17076. 144 pages. Houston:

Johnson Space Center.

Score, R., T.V.V. King, CM. Schwarz, A.M. Reid, and B. Mason

1982. Descriptions of Stony Meteorites. In U.B. Marvin and B. Mason,

editors, Catalog of Meteorites from Victoria Land, Antarctica,

1978-1980. Smithsonian Contributions to the Earth Sciences,

24:19^8.

Score, R., CM. Schwarz, and B. Mason

1984. Descriptions of Stony Meteorites. In U.B. Marvin and B. Mason,

editors, Field and Laboratory Investigations of Meteorites from

Victoria Land, Antarctica. Smithsonian Contributions to the Earth

Sciences, 26:23-47.

Scott, E.R.D.

1984. Pairing of Meteorites Found in Victoria Land, Antarctica. Proceedings of the Ninth Symposium on Antarctic Meteorites. Memoirs of

National Institute of Polar Research, special issue, 35:102-125.

Yanai, K.

1982. Antarctic Meteorite Distribution Map of Allan Hills, Victoria Land,

Antarctica—Allan Hills-76, -77, -78 Meteorites. Tokyo: National

Institute of Polar Research.

1984. Locality Map Series of Antarctic Meteorites, Sheet 1 Allan Hills:

Explanatory Text of Locality Map of Allan Hills-76, Allan Hills-77,

and Allan Hills-78 Meteorites. Tokyo: National Institute of Polar

Research.
Appendix

Tables of ANSMET Meteorites

Terminology

Class and type: A = achondrite, unique; Au = aubrite; C = carbonaceous chondrite;

Di = diogenite; E = enstatite chondrite; EH = enstatite high-iron chondrite; Eu = eucrite;

Ho = howardite; H = high-iron chondrite; I = iron (IA, IIA, I IB, IVA = iron groups);

L = low-iron chondrite; LL = low-iron low-metal chondrite; M = mesosiderite; Sh =

shergottite; Ur = ureilite. Chondrite petrologic type is indicated by digit following the

abbreviation.

Olivine composition in mole percent Fe2Si04 (Fa).

Pyroxene (orthopyroxene or low-Ca clinopyroxene) composition in mole percent

FeSiO3 (Fs).

Degree of weathering: A = minor; metal flecks have inconspicuous rust haloes, oxide

stain along cracks is minor. B = moderate; metal flecks show large rust haloes, internal

cracks show extensive oxide stain. C = severe; specimen is uniformly stained brown, no

metal survives.

Degree of fracturing: A = slight; specimen has few or no cracks and none penetrate the

entire specimen. B = moderate; several cracks extend across the specimen, which can be

readily broken along the fractures. C = severe; specimen has many extensive cracks and

readily crumbles.

Locations: ALH = Allan Hills; BTN = Bates Nunatak; DRP = Derrick Peak; EET =

Elephant Moraine; ILD = Inland Forts; MBR = Mount Baldr; MET = Meteorite Hills;

OTT = Outpost Nunatak; PCA = Pecora Escarpment; PGP = Purgatory Peak; RKP =

Reckling Peak; TIL = Thiel Mountains; TYR = Taylor Glacier.

Classification by S.J.B. Reed and S.O. Agrell (*); by S.G. McKinley and K. Kiel (f);

by C.B. Moore (+).

Abbreviations: n.d. = no data.

NOTE: The following meteorites were characterized after the manuscript had been

submitted:

H5 META78009,010,011,012,018

H6 META78006,007, 013,014,016, 017,019, 020,022, 023, 024,025,026, 027

L6 META78002, 003, 004, 005, 021, 028

The possibility of pairings within each group should be considered. Classifications by

Brian Mason.

121
122 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Meteorites listed by source area in numerical sequence (fractions of grams in weight dropped unless

total weight is less than 1 gram).

Specimen

number

ALH

76001

76003

76004

76002

76005

76006

76007

76008

76009

77001

77002

77003

77004

77005

77007f

77008t

77009

77010

77011

77012

77013f

77014

77015

77016f

77017f

77018f

77019t

77021

77022f

77023t

77025

77026f

77027f

77029f

7703If

77033

77034f

77036f

77038f

770391

7704If

77042f

77043f

77045f

770461

77047f

77049f

77050f

7705If

77052t

77054t

77056t

77058t

77060t

Weight

(g)

20151

10495

53

307

317

271

79

281

3950

252

235

780

2230

483

99

93

236

296

292

180

23

309

411

78

78

52

60

17

16

21

19

20

4

1

0.5

9

2

8

19

8

17

20

11

18

8

20

7

84

15

112

10

12

4

64

Class

and

type

L6

L6

LL3

I

Eu

H6

L6

H6

L6

L6

L5

C3O

H4

Sh

H5

L6

H4

H4

L3

H5

L3

H5

L3

H5

H5

H5

L6

H5

H5

H5

H5

L6

L6

C3O

L3

L3

L3

L3

H5

H5

LL6

H5

L3

H5

H6

L3

L3

L3

H5

L3

H5

H4

H5

LL5

%Fain

olivine

25

25

0-34

37-57

18

24

19

24

25

25

4-48

17-20

28

19.1

24.6

18

18

4-36

18

9-28

18

1-21

18.6

18.8

19.0

24.9

18

19.1

19.1

18

24.3

25.0

23.0

n.d.

8-38

n.d.

n.d.

19.0

18.5

30.7

19.0

1-37

18.7

19.0

n.d.

n.d.

n.d.

18.8

n.d.

18.5

18.8

18.8

28.1

% Fs in

pyroxene

21

21

0-53

16

21

17

21

21

22

2-25

15-27

23

16.7

20.6

16

15-18

1-33

16

1-35

17

4-24

17.1

16.3

17.0

21.4

17

17.0

16.8

17

20.7

21.5

2.6

n.d.

8-9

n.d.

n.d.

17.1

16.3

25.1

16.6

1-28

17.0

16.7

n.d.

n.d.

n.d.

16.5

n.d.

16.9

16.3

16.1

23.2

Degree

of

weathering

A

A

A

A

C

B

B/C

B

B

B

A

C

A

B

A

C

C

C

C

B

C

C

B

B

B/C

B/C

C

A

B

C

B/C

B/C

A/B

B/C

C

B/C

B

A/B

A/B

A

A/B

B/C

A

A/B

C

B/C

B/C

A

B/C

B

A/B

B

A

Specimen

number

77061

77062

77063t

77064

77066t

77069t

77070t

77071

77073t

77074

77076t

77078t

77079t

77081

77082t

77084t

77085t

77086

77087t

77088

77089t

7709It

77092t

77094t

77096f

77098t

77100t

771011

77102

77104t

77106t

77108t

771111

77112t

77113t

77114t

77115t

77117f

77118

77119

77120t

77122t

77124

77125t

77126t

77127t

77129t

77130t

77131t

77132t

77133t

77134t

77136t

77138t

77140

Weight

(g)

13

17

3

6

5

0.8

18

11

10

12

2

24

8

9

12

44

46

19

31

51

8

4

45

7

2

8

18

4

12

6

8

0.7

52

22

2

45

154

21

8

6

4

5

4

19

25

4

2

25

26

115

19

19

4

2

79

Class

and

type

H5

H5

H5

H5

H5

L6

H5

H5

H5

H5

H5

H5

H5

"H(?)"<

%Fain

olivine

18

18

18.0

18

19.0

25.4

18.4

18

18.8

18

19.5

19.5

18.2

• 11

* (Acapulco-like)

H5

H5

H5

H5

H5

H5

L6

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H6

H5

H5

H5

L3

L5

H5

H5

H5

H5

H5

H5

H5

L5

H5

H5

H6

H5

H6

H6

H5

H5

L3

19.3

18.8

18.8

19

19.0

19

25.5

18.9

18.5

18.5

18.7

18.7

19.2

18.6

19

18.9

18.8

18.5

19.0

18.7

18.7

19.6

n.d.

24.4

19

18

18.5

19.1

19

17.2

18.3

25.0

18.9

18.9

19.2

19.0

19.0

18.9

19.1

19.2

8 ^ 4

%Fsin

pyroxene

17

17

16.8

17

17.4

21.4

16.8

17

17.7

17

16.1

16.7

15.8

11

16.5

16.8

17.6

17

16.7

17

21.4

16.1

16.5

16.2

17.1

16.7

16.4

17.0

15

16.9

16.5

15.9

16.6

16.7

17.2

17.2

n.d.

21.0

17

17

16.0

16.8

17

15.5

16.2

21.1

16.6

16.5

16.8

16.9

17.0

16.7

16.4

17.0

2-17

Degree

of

weathering

B

B

B

B

A

B/C

B

B

A/B

B

B

B

A

B

A/B

A/B

B

C

B

C

B

B/C

A

B

A

B

A/B

B

B

A

A/B

A/B

A/B

A

B

B

B/C

A/B

C

C

A/B

B

C

A/B

A/B

B

B

A

A/B

A/B

A

A

A/B

A

B
NUMBER 28 123

TABLE A.—Continued.

Specimen

number

77142f

77143f

77144

77146f

77147f

77148"

77149f

77150

77151f

77152t

77153f

77155

77156f

77157f

77158f

77159f

77160

77161f

77162f

77163f

77164

77165

77166f

77167

77168f

77170f

77171f

77173f

77174f

77175f

77176f

77177

77178f

77180

77181f

77182

77183

77184f

77185f

77186f

77187f

77188f

77190

77191

77192

77193f

77195f

77197f

77198f

77200f

77201f

77202f

77205f

77207f

77208

Weight

(g)

3

39

8

18

19

13

26

58

17

18

12

305

18

88

20

17

70

6

29

24

38

31

139

611

25

12

24

26

32

23

55

368

6

191

33

1135

288

128

28

122

52

109

387

642

845

7

5

20

7

0.9

15

3

3

5

1733

Class

and

type

H5

H5

H6

H6

H6

H6

H6

L6

H5

H5

H5

L6

EH4

H6

H5

L6

L3

H5

L6

L3

L3

L3

L3

L3

H5

L3

H5

H5

H5

L3

L3

H5

L3

L6

H5

H5

H6

H5

L3

H5

H5

H5

H4

H4

H4

H5

H5

L3

L6

H6

H5

H5

H5

H5

H4

%Fain

olivine

18.9

18.7

19

18.9

19.0

18

19.1

25

18.9

18.7

19.2

24

0.8

18.6

18.9

24.4

3^16

19.3

25.3

n.d.

6-39

8-33

n.d.

2-41

19.0

n.d.

18.9

19.1

18.3

n.d.

0.3-34

18

1-36

24

20.0

19

19

17.8

n.d.

18.8

18.1

18.1

17-19

16-18

16-18

19.0

18.9

10-27

24.4

19.7

18.8

18.6

18.8

17.8

17

%Fsin

pyroxene

17.1

16.2

17

16.9

16.6

16

16.9

22

16.4

16.9

16.7

20

1.5

15.7

16.9

20.8

6-40

17.1

20.9

n.d.

3—41

6-35

n.d.

3-17

16.5

n.d.

17.0

17.0

16.0

n.d.

1-37

16

2 ^ 0

20

17.3

17

16

15.9

n.d.

16.0

16.3

16.1

15-22

14-16

15-21

15.7

16.4

4-21

20.6

17.6

15.3

16.6

16.7

16.7

14

Degree

of

weathering

A/B

A/B

B

A/B

A/B

C

A/B

C

A

A

A

A/B

B

A/B

B

A/B

C

B

A

B/C

C

c

c

c

B

B/C

A/B

B

A

B/C

B

C

B/C

C

B

C

C

B

A/B

A/B

A/B

A/B

C

C

c

A

A

A/B

B

C

A

B

B

A/B

C

Specimen

number

77209f

7721If

77212t

77213t

77214

77215

77216

77217

77218t

77219

77220t

77221

77222t

77223

77224

77225

77226

77227t

77228t

77230

77231

77232

77233

77235t

77237t

77239t

77240t

77241t

77242t

77244t

77245t

77246t

77247t

77248t

77249

77250

77251t

77252

77253t

77254

77255

77256

77257

77258

77259

77260

77261

77262

77263

77264

77265t

77266t

77267t

77268

77269

Weight

(g)

32

27

17

8

2111

820

1470

413

45

637

69

229

125

208

787

5878

15323

16

19

2473

9270

6494

4087

5

4

19

25

144

56

40

33

42

44

96

504

10555

69

343

24

246

765

676

1996

597

294

744

412

862

1669

11

18

108

104

272

1045

Class

and

type

H6

L3

H6

H5

L3

L3

L3

L3

L5

M

H5

H4

H4

H4

H4

H4

H4

H5

H5

L4

L6

H4

H4

H5

H5

H6

H5

L3

H5

L3

H5

H6

H5

H6

L3

I

L6

L3

H5

L5

I

Di

Ur

H6

H5

L3

L6

H4

I

H5

H5

H5

L5

H5

L6

%Fain

olivine

18.8

n.d.

18.9

18.6

1-49

22-26

15-35

17-25

23.4

26

17.7

15

18.0

17

19

17

18

18.9

18.5

22-25

24

17

14-21

18.9

18.5

18.7

18.8

n.d.

18.8

n.d.

19.2

19.2

18.8

18.7

7-35

25.0

22-28

19.2

23

13

18

18

7-23

24

15-19

19

17.6

19.6

24.7

18

24

%Fsin

pyroxene

16.4

n.d.

17.0

16.5

4-23

9-21

14-23

9-26

19.1

24-28

16.0

13-15

15.3

15-23

17

16

16

16.6

16.3

18-29

21

15

15-17

16.7

15.8

15.9

16.0

n.d.

16.2

n.d.

17.2

16.5

16.4

16.7

2-25

21.3

2-22

16.9

20

23

12

16

15

1-28

21

13-16

16

15.9

17.7

20.9

16

22

Degree

of

weathering

B

B/C

A/B

A

C

B

A/B

B

A

B

B

C

A/B

C

C

c

c

A

B

C

A/B

C

C

A/B

A

B

A

C

B

B/C

A/B

B

A/B

B/C

C

B

B

A/B

A/B

A/B

A

B/C

C

C

B

B/C

A/B

B

B

A

C

B
124 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

77270

11211

77272

77273

77274

77275f

77277

1121%

77279f

77280

77281

77282

77283

77284

77285

77286

77287

77288

77289

77290

7729It

77292

77293f

77294

77295f

77296

77297

77299

77300

7730If

77302

77303t

77304

77305

77306

77307

78001+

78002+

78003

78004*

78005+

78006

78008

78010+

78012

78013

78015*

78017+

78018+

78019

78021

78023

78025+

78027*

Weight

(g)

589

610

674

492

288

25

143

313

175

3226

1231

4127

10510

376

271

246

230

1880

2186

3784

6

200

110

1351

141

963

952

261

235

55

236

79

650

6444

20

181

85

11

125

36

28

8

7

1

38

4

35

3

18

30

17

10

8

29

Class

and

type

L6

H6

L6

L6

H5

H5

L6

LL3

H5

L6

L6

L6

I

L6

H6

H4

H5

H6

I

I

H5

L6

L6

H5

EH4

L6

L6

H3

H5

L6

Eu

L3

L4

L6

C2

C3

H5

H6

L6

H5

H5

Ho

H5

H5

H5

L3

LL(?L)3

L3

H5

Ur

H5

H5

H5

H5

% Fa in

olivine

24

18

24

24

18

18.3

24

11-29

18.8

24

24

24

25

18

17

18

19

18.9

24

24.7

17

0.8

24

24

11-21

18

24.9

n.d.

18-27

24

1-45

1-30

18.6

19.0

24

19.2

19.3

18

19.4

18

11-45

8-35

3-43

19.2

22

18

18

18.9

19.3

% Fs in

pyroxene

21

16

20

20

16

15.6

20

9-21

17.1

21

20

20

21

16

12-16

16

17

15.9

20

20.9

15

1.7

21

20

15-20

16

20.9

37-64

n.d.

13-19

21

1

1-12

20

25-61

16

16

1-31

18

16

16

Degree

of

weathering

A/B

C

B/C

B

C

A

A/B

A

A

B

B

B

A/B

C

C

c

c

A

B

B

A

B

A/B

A

A

C

A

A

B/C

B

B/C

A

A

B

A

C

B

A

B

B

F

B/C

A

Specimen

number

78028

78029+

78031

78033+

78035

78037+

78038

78039

78040

78041+

78042

78043

78044

78045

78046

78047*

78048

78049+

78050

78051

78052*

78053

78055+

78057

78059+

78062

78063+

78065+

78067

78069+

78070

78074

78075

78076

78077

78078

78079

78080

78081*

78082+

78084

78085

78086*

78088*

78090*

78092*

78094*

78096*

78098*

78100

78101

78102

78103

78104

78105

Weight

(g)

4

4

5

5

2

0.5

363

299

212

118

214

680

164

397

70

130

191

96

1045

120

97

179

14

9

9

11

77

7

8

4

10

200

281

276

331

290

5

25

18

24

14280

219

9

5

8

16

4

7

2

85

121

337

590

672

942

Class

and

type

H5

H4

H5

H4

H6

L3

L3

L6

Eu

L3

L6

L6

L4

L6

L3

H5

L6

H5

L6

H4

H5

H4

L6

H4

L6

LL6

LL6

H6

H6

H6

L4

L6

H5

H6

H4

L6

H5

H5

H5

LL6

H4

H5

H6

H5

H5

H5

H5

H5

H5

I

L6

H5

L6

L6

L6

% Fa in

olivine

18

19.2

18

19.2

18

7-38

4-42

24

0-41

24

25

23-25

25

8-25

18.8

24

19.4

23

18

17.9

17

25.5

18

21.5

29

29.1

18.0

18

19.1

23

24

18

18

19

24

18

18

19.1

27.7

18

18

19.0

18.8

18.7

19.0

19.1

18.9

18.9

24

18

24

24

23

% Fs in

pyroxene

16

16

16

2-19

21

33-52

20

21

19-24

21

8-20

21

20

15-18

16

16

24

16

13-25

21

16

16

15-18

20

16

16

8-24

16

21

17

20

20

20

Degree

of

weathering

B

B

B

C

B

A

B

B

B

B/C

B/C

B

A/B

B

B

C

C

B

B

A

B

B

B

B/C

B

C

A/B

A

B/C

B

B/C

B

B

B
NUMBER 28 125

TABLE A.—Continued.

Specimen

number

78106

78107

78108

78109

78110

78111

78112

78113

78114

78115

78116*

78117+

78119+

78120

78121*

78122

78123+

78124

78125*

78126

78127

78128

78129+

78130

78131

78132

78133

78134

78135*

78136+

78137

78138+

78139*

78140+

78141

78142*

78145+

78146

78147*

78149+

78150

78152

78153

78154+

78156

78157+

78158

78159

78160*

78162+

78163+

78164

78165

78168+

78169+

Weight

(8)

465

198

173

233

161

127

2485

299

808

848

128

4

103

44

30

5

18

28

19

607

195

155

128

2733

269

656

60

458

131

52

70

11

17

17

24

32

34

17

31

23

16

5

152

12

9

63

15

23

16

33

10

25

21

34

22

Class

and

type

L6

H5

H5

LL5

H5

H5

L6

Au

L6

H6

H5

H5

L3

H4

H5

H6

H5

H6

L6

L6

L6

H5

H5

L6

L6

Eu

L3

H4

H6

H5

H6

LL3

H5

H4

H5

L5

H6

H5

H5.6

L3

H5

H6

LL6

H5

L6

H4

Eu

H5

H5

L3

H5

H5

Eu

H4

H6

% Fa in

olivine

24

18

18

28

18

18

25

25

18

18.7

18.5

0-28

18

19.2

19

19.3

17

25.0

25

24

19

19.4

25

25

1-34

18

19.0

19.1

17

0-35

19.3

18.4

18

24.2

19.6

18

19.4

18-31

18

18

29

19.3

24

19.0

18

19.3

2-30

18.7

18

19.2

19.2

% Fs in,

pyroxene

20

17

16

23

16

16

20

20

16

16

17

15

21

20

17

21

21

40-458

1-16

15-20

15

16

16

16

16

24

21

40-68

16

16

37-61

Degree

of

weathering

A/B

C

B

A/B

B/C

B/C

B

A/B

B/C

B

B

A

A

B

B

B

B/C

C

B

B/C

B/C

A

B/C

B

A

B

B

A

B

B/C

B

B

A

B

B

A

B

B

Specimen

number

78170+

78171+

78172+

78173+

78174+

78176+

78178+

78180+

78182

78184

78186

78188

78189

78190

78191

78193

78194

78196

78197

78199

78201

78203

78205

78207

78209

78211

78213

78215

78217+

78219+

78221

78223

78225

78227

78229

78231

78233

78235+

78236

78238

78239+

78241

78243

78245

78247

78249

78251

78252

78253+

78255+

78257+

78259+

78261

78262

Weight

(g)

21

23

29

20

13

8

7

8

10

8

3

0.9

23

20

20

13

25

11

20

13

10

11

9

8

12

11

10

6

8

8

5

6

5

2

2

2

1

19

14

10

16

7

2

4

3

4

1312

2789

7

3

2

6

5

26

Class

and

type

H3

L6

H4

H5

H5

L3

H5

L3

H5

H6

L3

L3

H6

H5

H6

H4

H5

H4

H5

H5

H5

H5

H5

H6

H5

H6

H6

H6

H5

H5

H5

H4

H5

H5

H6

H6

H5

L3

L3

L3

L3

H5

L3

H5

H5

H6

L6

I

H5

H5

H5

H5

C2

Ur

%Fain

olivine

3-36

25.4

19.7

19.7

18.2

8-26

19.0

2-33

18

18

3-36

1-34

18

18

18

18

18

18

18

18

18

18

18

19

18

18

18

18

18.8

19.4

18

18

18

18

18

18

18

8-28

2-37

2-34

1-34

18

1-36

18

18

18

23

18.9

19.4

19.2

19.7

0-50

22

% Fs in

pyroxene

16

16

3-24

5-29

16

16

16

16

16

16

16

16

16

16

16

17

15

16

15

16

16

16

16

16

15

16

16

3-26

3-21

16

3-30

16

16

16

20

1-8

19

Degree

of

weathering

B

B

B

B

B

B

B

B

C

B/C

B/C

B/C

B

B

B/C

B

B

B

B

B

B/C

B

B/C

B/C

B

B

B

B

A

B

A

A

B/C
126 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

79001

79002

79003

79004

79005

79006

79007

79008

79009

79010

79011

79012

79013

79014

79015

79016

79017

79018

79019

79020

79021

79022

79023

79024

79025

79026

79027

79028

79029

79031

79032

79033

79034

79035

79036

79037

79038

79039

79040

79041

79042

79043

79045

79046

79047

79048

79049

79050

79051

79052

79053

79054

79055

80101

Weight

(g)

32

223

5

35

60

41

142

12

76

25

14

192

28

11

64

1146

310

121

12

4

29

31

68

22

1208

572

133

16

506

3

3

281

13

38

20

15

50

108

13

20

11

62

115

90

19

37

54

27

24

23

86

36

15

8725

Class

and

type

L3

H6

LL3

H5

H6

H5

L6

H5

H5

H5

H5

H5

H5

H5

H5

H6

Eu

L6

H6

H6

H5

L3.4

H4

H6

H5

H5

L6

H6

H5

H5

H5

L6

H6

H4

H5

H6

H5

H4

H5

H5

H5

L6

L3

H5

H5

H5

H6

H5

H5

L6

H5

H5

H6

L6

% Fa in

olivine

6-39

16

10-38

16

18

18

23

17

18

17

18

17

18

18

17

17

28-53

23

17

17

18

1-28

17

17

17

18

24

18

18

16

16

24

18

17

18

18

17

16

18

18

18

23

2-38

18

18

18

18

18

18

23

17

18

18

24

%Fsin

pyroxene

2-31

18

5-26

14

16

15

19

15

15

15

16

15

16

16

15

15

20

15

15

17

9-22

14-17

15

15

16

20

16

16

14

14

20

16

14-18

16

16

15

15

15

16

16

20

2-29

15

15

16

16

15

15

20

15

16

16

20

Degree

of

weathering

C

C

B

B/C

B

B/C

A/B

B

C

B/C

B/C

C

c

B

B

B/C

A

B/C

B

B/C

B

A/B

B/C

C

C

B

B

B

C

C

C

B

B

B

B

B

C

B

B

B

B

C

C

B

B

B

C

C

C

B/C

B/C

B

B/C

B

Specimen

number

80102

80103

80104

80105

80106

80107

80108

80110

80111

80112

80113

80114

80115

80116

80117

80118

80119

80120

80121

80122

80123

80124

80125

80126

80127

80128

80129

80130

80131

80132

80133

81001

81002

81003

81004

81005

81006

81007

81008

81009

81010

81011

81012

81013

81014

81015

81016

81017

81018

81019

81020

81021

81022

81023

Weight

(g)

471

536

882

445

432

178

125

168

42

331

313

233

306

191

89

2

34

60

39

50

28

12

139

35

47

138

93

5

20

153

4

53

14

10

5

31

255

164

44

229

219

406

37

Mill

188

5489

3850

1434

2237

1051

1353

695

913

418

Class

and

type

Eu

L6

I

L6

H4

L6

L6

L6

H5

L6

L6

L6

L6

L6

L6

H6

L6

L6

H4

H6

H5

H5

L6

H6

H5

H4

H5

H6

H4

H5

L3

Eu

C2

C3V

C2

A

Eu

Eu

Eu

Eu

Eu

Eu

Eu

I

I

H5

L6

L5

L5

H5

H5

E6

H4

L5

%Fain

olivine

24

24

19

24

24

24

18

24

24

24

24

24

24

17

24

24

19

18

18

18

24

19

18

18

18

18

19

18

1-35

0-52

0-60

0-52

11-40

19

25

25

24

19

19

19

25

% Fs in

pyroxene

34-52

20

20

16-19

20

20

20

16

20

20

20

20

20

20

15

20

20

17

16

16

16

20

17

16

15-20

15

16

16-22

16

5-30

59

0-2

1

0-2

7-47

35-60

38-55

32-59

30-63

31-57

33-60

33-62

16

21

21

21

16

16

0-1

17

21

Degree

of

weathering

A

B

B

C

B

B

B

B

B

B

B

B

B/C

B

B

B

B

B/C

B/C

C

B

B/C

A/B

B

B

B

B/C

B

B

B

A

A

A/B

A/B

A/B

A

A/B

A/B

A

A

A/B

A/B

B

B

B

B

B/C

B

A

B/C

B
NUMBER 28 127

TABLE A.—Continued.

Specimen

number

81024

81025

81026

81027

81028

81029

81030

81031

81032

81033

81034

81035

81036

81037

81038

81039

81040

81041

81042

81043

81044

81045

81046

81047

81048

81049

81050

81051

81052

81053

81054

81055

81056

81057

81058

81059

81060

81061

81062

81063

81064

81065

81066

81067

81068

81069

81070

81071

81072

81073

81074

81075

81076

81077

81078

Weight

(g)

798

379

516

3835

80

153

1852

1595

111

252

255

256

252

320

229

206

195

729

534

106

387

90

17

82

191

9

26

43

29

3

2

5

1

8

66

540

28

24

0.5

5

191

13

9

228

24

7

4

2

3

3

8

16

10

4

6

Class

and

type

L3

L3

L6

L6

L6

L6

L3

L3

L3

H5

H5

H6

H5

H6

H6

H5

L4

H4

H5

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

L3

H6

H6

H4

H4

H4

M

L3

L3

H5

H5

H5

L3

L3

H5

H4

L3

H5

H5

H5

H4

H4

H5

H6

H5

H6

% Fa in

olivine

3-28

1-41

25

25

25

25

1-49

1-43

0-42

18

19

19

19

20

19

19

25

18

19

18

18

18

18

18

18

18

18

18

18

1-29

19

19

19

19

18

28

2-28

3-33

18

18

18

10-41

1-44

19

19

4-38

19

19

19

19

19

19

19

19

19

%Fsin

pyroxene

2-24

3-40

21

21

21

21

5-33

3-35

2-14

16

17

17

17

17

17

17

21

15-23

17

15

16

16

16

16

16

16

16

16

16

I^t2

17

16

17

13-21

15

25-32

5-27

5-27

16

16

15

5-24

1-25

17

16

1-31

17

17

17

8-18

16

17

16

17

16

Degree

of

weathering

C

C

B

C

B

C

B/C

C

c

c

B

C

C

B

C

A/B

B/C

C

C

B/C

C

c

c

B/C

B/C

B/C

C

B/C

C

C

B

B

B

B

C

C

C

B/C

C

B/C

C

B/C

C

C

B

B/C

B/C

B

B/C

B/C

B

B

B

B

B/C

Specimen

number

81079

81080

81081

81082

81083

81084

81085

81086

81087

81088

81089

81090

81091

81092

81093

81094

81095

81096

81097

81098

81099

81100

81101

81102

81103

81104

81105

81106

81107

81108

81109

81110

81111

81112

81113

81114

81115

81116

81117

81118

81119

81120

81121

81122

81123

81124

81125

81126

81127

81128

81129

81130

81131

81132

81133

Weight

(g)

7

17

5

6

7

16

16

6

8

4

11

10

12

16

271

152

59

83

80

71

152

155

119

196

136

184

93

48

140

69

1

3

210

150

111

79

155

2

33

85

107

14

88

21

2

9

10

22

15

16

32

30

13

5

21

Class

and

type

H6

H5

H5

H5

H5

H5

L3

H6

L3

H5

H5

H5

H5

H4

H6

H6

H4

H6

H4

M

L6

H5

Ur

H6

H6

H4

H4

L6

L6

H5

H4

H5

H6

H6

H5

H4

H5

H5

H4

H5

L4

H5

L3

L6

LL6

H5

H5

H5

H6

H5

H5

H5

L6

H5

H5

%Fain

olivine

19

19

19

19

19

19

1-39

19

2-29

19

19

19

19

19

20

19

18

19

18

25

19

10-22

19

19

19

18

24

24

18

19

19

19

19

18

18

19

19

18

19

24

18

8-40

25

30

19

19

19

19

19

18

18

25

18

18

% Fs in

pyroxene

16

17

17

17

16

16

2-25

16

3-31

17

17

16

16

17

17

16

16

17

16

28

21

17

17

17

17

16

20

21

16

17

17

17

17

16

16

17

17

14-21

16

21

16

1-24

21

25

17

17

16

17

17

16

16

22

16

16

Degree

of

weathering

C

A/B

B

B

B

B

C

B

B/C

B

B

B

B

B

A/B

C

B/C

B

B

C

A/B

B

A/B

B/C

B/C

C

c

B

B

B

B

B/C

B/C

B/C

B/C

B/C

C

B

B

B/C

B

B/C

B

B

B

B

B

B

B/C

B/C

A/B

B

A/B

B

B
128 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

81134

81135

81136

81137

81138

81139

81140

81141

81142

81143

81144

81145

81146

81147

81148

81149

81150

81151

81152

81153

81154

81155

81156

81157

81158

81159

81160

81161

81162

81163

81164

81165

81166

81167

81168

81169

81170

81171

81172

81173

81174

81175

81176

81177

81178

81179

81180

81181

81182

81183

81184

81185

81186

81187

81188

Weight

(g)

15

10

1

9

4

7

14

1

1

13

3

21

24

2

13

9

2

5

10

4

1

5

20

12

2

10

12

122

59

82

20

6

26

59

8

6

59

24

33

26

33

13

95

17

30

14

17

15

5

104

17

65

23

40

9

Class

and

type

H6

H5

H5

H6

H5

H5

H4

H5

H4

H5

H5

L3

H6

H4

H5

H4

L6

LL5

H5

L5

H6

H5

L3

H4

H5

L6

H6

H5

L3

H5

H5

H5

H5

L6

H5

H5

H5

H5

L6

H5

H5

H5

H5

H4

H5

H5

H6

L6

H5

H5

L4

LL6

H5

A

H5

% Fa in

olivine

18

19

20

19

19

19

19

19

18

18

19

5-40

18

19

19

19

25

28

18

24

19

19

4-42

19

19

25

19

19

1-40

19

18

19

19

25

19

18

19

19

24

19

19

19

19

19

19

19

18

25

18

17

24

30

18

4

19

%Fsin

pyroxene

16

16

17

17

17

17

17

17

16

16

16

3-23

16

16

17

16

22

23

16

21

17

17

1-30

17

17

21

17

16

4-20

17

16

16

16

22

17

16

17

17

21

16

17

17

17

16

17

17

16

22

16

15

20

25

16

6.5

17

Degree

of

weathering

B/C

B

B

B/C

B

B/C

B/C

B/C

B/C

B/C

B

B

C

B

B

B

C

B/C

B

B

B

A/B

B/C

B/C

B/C

B/C

C

C

C

C

B

B

B

B/C

C

B

B

B/C

C

A/B

B

A/B

B

B/C

B/C

B

C

B

B

C

A/B

A/B

B

B/C

A/B

Specimen

number

81189

81190

81191

81192

81193

81194

81195

81196

81197

81198

81199

81200

81201

81202

81203

81204

81205

81206

81207

81208

81209

81210

81211

81212

81213

81214

81215

81216

81217

81218

81219

81220

81221

81223

81224

81225

81226

81227

81228

81229

81230

81231

81232

81233

81234

81235

81236

81237

81238

81239

81240

81241

81242

81243

81244

Weight

(g)

3

48

30

9

13

17

5

9

68

0.9

16

9

7

5

4

7

3

4

14

2

14

0.6

7

11

3

4

11

2

5

6

24

3

9

10

14

14

3

11

8

40

13

9

5

25

5

7

41

27

24

32

41

34

20

15

5

Class

and

type

E4

L3

L3

H5

H6

H5

H5

H6

H5

L5

H4

H4

H5

H5

L6

H6

L6

H4

H5

Di/M

H5

H6

H5

H4

H5

L3

H5

H5

L6

H5

H5

H5

L6

H6

H6

H6

H5

H5

H5

L3

H5

H4

H5

H5

H4

L6

H5

H5

H5

H5

H5

H5

H5

L3

H5

% Fa in

olivine

2

0.3-32

2-29

19

18

19

18

18

17

24

19

19

18

19

25

18

25

18

18

18

19

18

18

19

0.2-38

18

18

24

19

19

18

25

18

19

19

19

19

18

7-32

18

19

18

19

18

25

18

18

19

19

19

17

18

5-44

19

% F s in

pyroxene

3

4-28

1-30

16

16

16

16

16

15

21

16

17

16

17

21

16

23

15-21

16

25

16

17

16

16

17

0.1-45

16

17

20

16

17

16

21

16

17

17

17

17

16

2-30

16

16

16

17

16

21

16

16

16

17

18

14

17

6-31

17

Degree

of

weathering

C

C

c

A/B

B

B

B

B

B/C

B/C

C

B/C

B/C

C

C

B

B

B/C

C

C

B/C

B

B

B/C

B/C

B/C

A

C

C

C

B

B/C

C

A/B

B/C

B

C

B

B/C

C

B

B/C

B

C

C

C

A/B

B

C

B

C

B

B/C

C

B
NUMBER 28 129

TABLE A.—Continued.

Specimen

number

81245

81246

81247

81248

81249

81250

81251

81252

81253

81254

81255

81256

81257

81258

81259

81260

81261

81262

81263

81265

81266

81267

81268

81269

81270

81271

81272

81273

81274

81275

81276

81277

81278

81279

81280

81281

81282

81283

81284

81285

81286

81287

81288

81289

81290

81291

81292

81293

81294

81295

81296

81297

81298

81299

Weight

(g)

4

3

104

5

10

17

158

2

10

9

12

28

29

1

10

124

12

55

6

8

12

27

18

5

4

28

23

43

19

11

42

7

1

27

55

46

31

0.6

10

20

28

78

20

4

2

4

13

2

9

105

13

20

16

0.5

Class

and

type

H5

H5

L6

H6

H5

H6

LL3

H5

H6

H6

H5

H5

L6

C3V

L3

E6

-H(?r

%Fain

olivine

19

19

25

18

18

18

1-29

18

18

18

18

18

24

0-28

0-22

* 11

* (Acapulco-like)

L6

H5

H5

L6

H4

H6

H5

H5

H6

L3

H6

H5

H5

H5

H5

L6

H4

L3

H5

L6

H5

H5

LL6

H5

H5

H6

L6

H4

H6

L3

H5

H5

H5

H5

H5

H6

L3

25

18

19

24

18

18

18

18

18

2-36

19

18

18

18

18

24

17

1-32

18

24

18

19

27

19

17

18

24

18

18

11-34

18

18

19

17

18

19

1-37

%Fsin

pyroxene

17

17

21

16

17

16

2-28

16

16

16

16

15

21

0-1

0-29

0.3

11

21

16

17

21

15-22

16

16

16

16

3-22

17

16

16

16

16

21

16

2-24

16

21

16

17

23

17

15

16

21

17

16

2-31

16

16

16

15

16

17

2-16

Degree

of

weathering

B/C

C

A/B

C

B/C

B

B/C

B

A/B

C

B

C

B

B

C

A/B

A/B

A/B

B

B/C

A/B

C

C

B/C

C

B

C

C

A/B

B

C

B

B

C

C

B

A/B

B/C

B/C

C

B

C

B

A

B

B

C

B

B

C

B/C

B

B

C

Specimen

number

81300

81301

81302

81303

81304

81305

81306

81307

81308

81309

81310

81311

81312

81313

81314

81315

82100

82101

82102

82103

82104

82105

82106

82107

82108

82109

82110

82111

82112

82113

82114

82115

82116

82117

82118

82119

82120

82121

82122

82123

82124

82125

82126

82127

82128

82129

82130

82131

82132

82133

82134

82135

82136

Weight

(g)

10

12

4

4

42

1

7

57

19

0.6

0.7

0.9

0.7

0.5

3

2

24

29

48

2529

399

363

35

9

14

47

39

63

28

61

41

48

18

4

111

24

7

2

142

111

26

178

140

5

15

14

45

1

6

20

28

12

4

Class

and

type

H5

H5

H5

H6

L6

H5

H5

L6

H5

H4

H6

L6

C2

Eu(?)

H5

"H(?r

%Fain

olivine

19

19

18

18

24

18

19

24

18

18

19

24

1-35

18

* 11

* (Acapulco-like)

C2

C30

H5

H5

L5

L6

Ur

L5

H5

H5

H3

US

H5

H6

H5

H5

H6

L5

US

H5

H5

L6

H5

L6

H6

L6

H4

H6

H4

H5

Ur

C2

E4

H4

H5

C4

H4

1-47

1-50

18

17

25

24

3

22

18

18

1-24

24

17

18

17

18

18

25

24

18

19

24

18

25

18

24

18

18

18

18

3

0.3

18

16

27

18

% Fs in

pyroxene

16

16

16

16

21

16

17

21

16

16

17

21

1-31

38

16

11

1-2

1-10

16

16

21

21

4

19

16

16

4-27

21

16

16

15

16

16

22

20

16

17

20

16

20

16

20

15

16

16

17

4

0.4

16

15

24

5-20

Degree

of

weathering

A/B

B/C

B/C

B/C

A/B

B/C

B

B

B/C

C

B

B

A

B

A/B

A

A

B/C

B

A

A/B

B

B/C

B/C

B/C

B/C

A/B

C

A/B

A/B

A/B

B

B

A/B

B/C

B

A

B

B

C

C

B/C

A/B

B/C

B/C

B

A

C

B/C

B/C

A

B
130 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

82137

82138

82139

82140

82141

82142

82143

82144

83001

83009

83010

83014

83015

83016

83100

83101

83102

84001

84004

84006

84007

84008

84011

84025

84027

84028

84029

84030

84031

84032

84033

84034

84042

84044

BTNA

78001

78002

78004

DRPA

78001

78002

78003

78004

78005

78006

78007

78008

78009

EETA

79001

79002

Weight

(g)

11

5

0.2

0.3

0.6

20

3

7

1569

2

395

1

3

4

863

639

1241

1931

9000

16000

706

302

138

5

8

736

120

6

12

8

60

44

51

147

161

4301

1079

15200

7188

144

134

18600

389

11800

59400

138100

7942

2843

Class

and

type

L5

H6

L6

L6

H5

L6

H6

H5

L4

Au

L3

Ur

Au

C2

C2

L6

C2

Di

H4

H4.5

Au

Au

Au

A

LL7(?)

C3V

C2

C2

C2

C2

C2

C2

C2

C2

L6

L6

LL6

I

I

I

I

I

I

I

I

I

Sh

Di

% Fa in

olivine

23

19

24

25

19

25

18

19

23-28

4-31

18

0.3-30

25

0-2

17-18

18

32-33

27

0-50

0-2

0-2

0-2

0-2

0-1

0-2

0-2

0-2

24

24

30

23-27

24-25

% Fs in

pyroxene

20

17

20

20

17

21

16

17

20-32

2-28

15

0-1

23

27

16-19

17-18

11

23

2

2

2

21

20

24

16-67

22

Degree

of

weathering

B

B

B

C

C

C

C

B

B

A/B

B

B

A/B

A/B

B

A

B/C

A/B

B

B/C

A

A/B

A

A/B

B

A

A

A

A

A

A

A

A

A

B

B

B

A

B

Specimen

number

79003

79004

79005

79006

79007

79009

79010

79011

EET

82600

82601

82602

82603

82604

82605

82606

82607

82608

82609

82610

82611

82612

82613

82614

82615

82616

83200

83201

83202

83203

83204

83205

83206

83207

83208

83209

83210

83211

83212

83213

83214

83215

83224

83225

83226

83227

83228

83229

83230

83231

83232

83234

83235

83236

Weight

(g)

436

390

451

716

200

140

287

86

247

150

1824

8210

1571

625

982

165

95

326

42

13

32

4

8

29

2

779

1060

1213

546

377

471

462

1238

263

520

426

543

402

2727

1398

510

9

44

33

1973

1206

313

530

66

211

181

255

6

Class

and

type

L6

Eu

Eu

Ho

H5

L5

L6

Eu

Ho

L3

H4

H5

H5

L6

L6

L6

LL6

H4

H6

L4

L6

L4

H5

H6

H4

H5

H6

L6

H5

LL6

L6

L6

H4

H5

L6

L6

H4

Eu

L3

L6

H6

C2

Ur

C2

Eu

Eu

Eu

I

Eu

Eu

Eu

Eu

Eu

%Fain

olivine

24

18

24

24

2-39

19

19

19

25

25

23

28

18

19

24

25

24

18

19

18

17-18

18-20

24-25

20

29-31

25

24

18

17-19

25

24-25

18-20

13-30

24-25

18

0.2-41

0.5-69

% Fs in

pyroxene

20

30-61

30-61

19-57

16

20

20

30-61

22-53

1-35

16

17

16

21

21

20

23

17

17

21

21

20

16

17

16

17-19

18

22-23

18-21

27

22

22

16-18

16-17

22-23

22

16-20

3-26

22-24

19

0-1

0.6-10

Degree

of

weathering

B

B

A

B

B

B

B

B

A

B/C

B

B

B/C

B

B

B/C

A/B

B/C

B

B

A

B

A/B

B

B/C

B/C

B/C

A/B

B/C

A

A/B

B

B

B/C

B/C

A/B

B/C

B

B

B

B/C

A/B

B/C

A/B

B

B

B

B

B

B

B

B
NUMBER 28 131

TABLE A.—Continued.

Specimen

number

83237

83245

83246

83247

83250

83251

83283

ILD

83500

MBRA

76001

76002

META

78001

78002

78003

78005

78006

78007

78010

78028

OTTA

80301

PCA

82500

82501

82502

82503

82504

82505

82506

82507

82508

82509

82510

82511

82512

82513

82514

82515

82516

82517

82518

82519

82520

82521

82522

82523

82524

82525

Weight

(g)

883

59

48

22

11

261

57

2523

1096

13773

624

542

1726

172

410

175

234

20657

36

91

54

890

8308

3094

3086

5316

480

389

286

254

149

55

239

130

7

16

41

22

125

23

1

46

11

114

40

Class

and

type

L6

I

Di

Di

C2

Eu

Eu

I

H6

H6

H4

L6

L6

L6

H6

H6

H5

L6

H3

C4

Eu

Eu

L6

L5

L5

Ur

LL6

L6

L6

L5

H4

H6

L5

L4

H4

H6

H5

E4

L5

H3

H5

H5

H6

H4

L6

%Fain

olivine

25-26

0.3-22

18

18

17

23

24

24

18

19

19

25

17-19

31

24

23

23

21

30

23

25

24

17

18

24

23

17

18

19

0.8

24

15-22

18

18

19

18

24

% Fs in

pyroxene

23-25

2-14

16

16

14-21

20

21

20

15

17

17

21

4-19

41-57

36-61

20

20

20

18

25

20

21

20

14

16

20

11-22

14

16

17

21

2-19

16

16

16

16

20

Degree

of

weathering

B

A/B

B/C

B

B

B

B

B

B/C

B

B

B

C

B/C

B

B

B/C

B

A

A

A

A/B

B

A/B

A

A/B

B

A

B

B

A/B

B

B

B/C

B/C

B

B

B/C

C

B/C

A

A/B

B

Specimen

number

82526

82527

82528

PGPA

77006

RKPA

78001

78002

78003

78004

79001

79002

79003

79004

79008

79009

79012

79013

79014

79015

80201

80202

80203

80204

80205

80206

80207

80208

80209

80210

80211

80213

80214

80215

80216

80217

80218

80219

80220

80221

80222

80223

80224

80225

80226

80227

80228

80229

80230

80231

80232

Weight

(g)

25

3

51

19068

235

8483

1276

167

3006

204

182

371

73

55

13

11

78

10022

813

545

4

15

54

47

18

10

10

11

2

19

5

9

44

8

7

21

124

52

7

25

8

8

160

8

11

14

58

238

80

Class

and

type

H6

H6

L6

I

L6

H4

L6

H4

L6

L6

H6

H5

L3

H6

H6

L5

H5

M

H6

US

H6

Eu

H3

H6

L3

H6

L5

H5

H6

H6

H6

L6

L4

H5

H5

L6

H5

H6

LL6

H5

Eu

L6

I

H5

L5

M

H5

H6

H4

%Fain

olivine

18

18

25

23

18

23

17

23

24

18

18

1-29

18

18

23

18

19

24

19

17-20

19

15-29

19

25

19

19

19

19

24

23

18

18

25

18

19

28

18

54

25

19

23

18

18

18

% Fs in

pyroxene

16

16

21

20

15

20

14-21

20

20

16

16

2-28

16

16

20

16

24

16

20

17

52-57

5-13

17

6-28

17

21

16

17

17

17

20

20

15

15

21

16

17

23

16

21

16

19

24

16

16

16

Degree

of

weathering

B

A

B/C

C

B

C

A

B

B

B

B/C

B

C

B

B/C

B/C

A/B

B

B

C

A

B

C

C

B

C

B/C

C

B/C

C

C

B

C

C

B

B/C

C

B

C

A/B

C

B/C

C

C

B

C

B
132 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

80233

80234

80235

80236

80237

80238

80239

80240

80241

80242

80243

80244

80245

80246

80247

80248

80249

80250

80251

80252

80253

80254

80255

80256

80257

80258

80259

80260

80261

Weight

(g)

414

136

261

16

22

18

6

61

0.6

7

3

14

37

6

1

11

10

4

29

11

5

68

7

153

9

4

20

8

62

Class

and

type

H5

LL5

LL6

H5

H4

LL6

Ur

H5

C3V

L4

H5

H5

H5

M

H5

LL6

H5

H5

H5

L6

LL5

H6

H6

L3

H5

M

E5

H5

L6

% Fa in

olivine

18

26

30

18

18

28

16

18

1-6

22

18

18

18

18

27

17

17

17

24

27

19

19

20-25

17

18

24

% Fs in

pyroxene

16

22

24

16

16

23

15

16

1-8

19

16

16

16

24

16

23

15

15

15

20

22

17

17

10-26

15

17-21

0-1

16

20

Degree

of

weathering

B/C

B

A/B

B/C

C

A/B

B

C

B

B/C

C

C

B/C

C

c

A/B

B/C

B/C

B

A/B

A/B

C

C

B

B/C

B/C

B/C

C

B

Specimen

number

80262

80263

80264

80265

80266

80267

80268

TIL

82400

82401

82402

82403

82404

82405

82406

82407

82408

82409

82410

82411

82412

82413

82414

82415

TYR

82700

Weight

(g)

32

17

24

8

10

24

3

221

282

476

50

322

1116

152

221

80

231

19

180

35

18

15

70

892

Class

and

type

H6

M

L6

H6

H6

H4

L5

L5

L6

LL6

Eu

L4

H6

L4

L4

LL3

H5

Di

L4

H5

H5

H5

H5

L4

%Fain

olivine

19

24

19

19

19

24

25

25

29

23

19

23

23

1-29

18

24

17

17

17

17

24

% Fs in

pyroxene

17

24

20

17

17

16

20

21

21

24

43-58

20

17

19

20

2-21

16

24

21

16

16

15

15

15-23

Degree

of

weathering

C

C

B

C

B/C

C

B/C

A/B

A/B

A/B

A

B

B

B

B/C

B

B

A

A/B

C

C

B

A/B

B
NUMBER 28 133

TABLE B.—Meteorites listed by class and source area in numerical sequence (fractions of grams in weight

dropped unless total weight is less than 1 gram).

Specimen

number

ALHA77306

ALHA78261

ALHA81002

ALHA81004

ALHA81312

ALH 82100

ALH 82131

ALH 83016

ALH 83100

ALH 83102

ALH 84029

ALH 84030

ALH 84031

ALH 84032

ALH 84033

ALH 84034

ALH 84042

ALH 84044

EET 83224

EET 83226

EET 83250

ALHA77307

ALHA77003

ALHA77029f

ALH 82101

ALHA81OO3

ALHA81258

ALH 84028

RKPA 80241

ALH 82135

PCA 82500

ALHA81189

ALH 82132

PCA 82518

ALHA77156f

ALHA77295f

RKPA80259

ALH A81021

ALHA81260

ALHA77299

ALHA78170+

ALH 82110

OTTA80301

PCA 82520

RKPA80205

ALHA77004

ALHA77009

ALHA77010

Weight

(g)

20

5

14

5

0.7

24

1

4

863

1241

120

6

12

8

60

44

51

147

9

33

11

181

780

1

29

10

1

736

0.6

12

91

3

6

22

18

141

20

695

124

261

21

39

36

23

54

2230

236

296

Class

and

type

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C2

C3

C3O

C3O

C3O

C3V

C3V

C3V

C3V

C4

C4

E4

E4

E4

EH4

EH4

E5

E6

E6

H3

H3

H3

H3

H3

H3

H4

H4

H4

Degree of

weathering

A

A

A

A/B

A

A

A

A/B

B

B/C

A

A

A

A

A

A

A

A

A/B

A/B

B

A

A

A/B

A

A/B

B

A

B

A

B

C

C

B

B/C

A

A/B

A

B

B/C

B/C

B/C

B

C

C

C

fracturing

CHOIN

A

A

B

A

A

A

B

B/C

B/C

C

B

B/C

B

A

B

A

B

B

B

B

C

A

A

A/B

A/B

A/B

A

B

A

C

B

B/C

A

B

B

B

B

A/B

A

B

B

A/B

B

C

A

A

Specimen

number

rDRITES

ALHA77056f

ALHA77190

ALHA77191

ALHA77192

ALHA77208

ALHA77221

ALHA77222f

ALHA77223

ALHA77224

ALHA77225

ALHA77226

ALHA77232

ALHA77233

ALHA77262

ALHA77286

ALHA78029+

ALHA78033+

ALHA78051

ALHA78053

ALHA78057

ALHA78077

ALHA78084

ALHA78120

ALHA78134

ALHA78140+

ALHA78157+

ALHA78168+

ALHA78172+

ALHA78193

ALHA78196

ALHA78223

ALHA79023

ALHA79035

ALHA79039

ALHA80106

ALHA80121

ALHA80128

ALHA80131

ALHA81022

ALHA81041

ALHA81043

ALHA81044

ALH A81045

ALHA81046

ALHA81047

ALHA81048

ALHA81049

ALHA81050

ALHA81051

ALHA81052

ALHA81056

ALHA81057

ALHA81058

ALHA81068

ALHA81073

ALHA81074

ALHA81092

ALHA81095

Weight

(g)

12

387

642

845

1733

229

125

208

787

5878

15323

6494

4087

862

246

4

5

120

179

9

331

14280

44

458

17

63

34

29

13

11

6

68

38

108

432

39

138

20

913

729

106

387

90

17

82

191

9

26

43

29

1

8

66

24

3

8

16

59

Class

and

type

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

Degree of

weathering

A/B

C

C

c

c

c

A/B

c

c

c

c

c

c

B/C

C

B

B

C

C

B/C

B/C

B

B

B

B

B/C

B/C

B

B/C

B

B

C

B/C

B

B

B/C

C

B/C

C

C

C

B/C

B/C

B/C

C

B/C

C

B

B

C

B

B/C

B

B

B/C

fracturing

C

B/C

C

c

A

C

C

C

C

C

B

B

B

B

B

B

B/C

A

B

B

C

B

B

B

C

B/C

B

A

C

C

C

B/C

B/C

B/C

B/C

B

C

B

B

A

A

C

A

A

B

A

C
134 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued.

Specimen

number

ALHA81097

ALHA81104

ALHA81105

ALHA81109

ALHA81114

ALHA81117

ALHA81140

ALHA81142

ALHA81147

ALHA81149

ALHA81157

ALHA81177

ALHA81199

ALHA81200

ALHA81206

ALHA81212

ALHA81231

ALHA81234

ALHA81267

ALHA81279

ALHA81290

ALHA813O9

ALH 82126

ALH 82128

ALH 82133

ALH 82136

ALH 84004

EET 82602

EET 82609

EET 82616

EET 83207

EET 83211

META78001

PCA 82511

PCA 82515

PCA 82524

RKPA78002

RKPA78004

RKPA80232

RKPA80237

RKPA 80267

ALH 84006

ALHA77007f

ALHA77012

ALHA77014

ALHA77016f

ALHA77017f

ALHA77018f

ALHA77021

ALHA77022f

ALHA77023f

ALHA77025

ALHA77038f

ALHA77039t

ALHA77042f

ALHA77045f

ALHA77051t

Weight

(g)

80

184

93

1

79

33

14

1

2

9

12

17

16

9

4

11

9

5

27

27

2

0.6

140

15

20

4

9000

1824

326

2

1238

543

624

149

7

114

8483

167

80

22

24

16000

99

180

309

78

78

52

17

16

21

19

19

8

20

18

15

Class

and

type

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4

H4.5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

weathering

B

C

C

B

B/C

B

B/C

B/C

B

B

B/C

B/C

C

B/C

B/C

B/C

B/C

C

C

C

B

C

B/C

B/C

B/C

B

B

B/C

B/C

B

B/C

B/C

B

B

A/B

B

A

B

C

C

B/C

B

C

C

B

B

B/C

C

A

B

C

A/B

A/B

A/B

A

A

»ree of

fracturing

A

C

B/C

A

B/C

B/C

A

B/C

A

B

B

B

B

A

A

B

B

A

B/C

B/C

A

A

A

A

A/B

B

B

B

A/B

A

B

B/C

B

B

A/B

B

A/B

A

A

B

A

B

A

B/C

A

B

Specimen

number

ALHA77054f

ALHA77058f

ALHA77061

ALHA77062

ALHA77063f

ALHA77064

ALHA77066f

ALHA77070f

ALHA77071

ALHA77073f

ALHA77074

ALHA77076f

ALHA77078f

ALHA77079t

ALHA77082f

ALHA77084f

ALHA77085f

ALHA77086

ALHA77087f

ALHA77088

ALHA77091f

ALHA77092t

ALHA77094f

ALHA77096f

ALHA77098f

ALH A77100t

ALHA77101f

ALHA77102

ALHA77104f

ALHA77106f

ALHA77108f

ALHA77112f

ALHA77113f

ALHA77114f

ALHA77118

ALHA77119

ALHA77120f

ALHA77122f

ALHA77124

ALHA77125f

ALHA77126f

ALHA77129f

ALHA77130f

ALHA77132f

ALHA77136f

ALHA77138f

ALHA77139f

ALHA77142f

ALHA77143f

ALHA77151f

ALHA77152t

ALHA77153f

ALHA77158f

ALHA77161f

ALHA77168f

ALHA77171f

ALHA77173f

ALHA77174f

ALHA77177

Weight

(8)

10

4

13

17

3

6

5

18

11

10

12

2

24

8

12

44

46

19

31

51

4

45

7

2

8

18

4

12

6

8

0.7

22

2

45

8

6

4

5

4

19

25

2

25

115

4

2

66

3

39

17

18

12

20

6

25

24

26

32

368

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

Degree of

weathering

B

B

B

B

B

B

A

B

B

A/B

B

B

B

A

A/B

A/B

B

C

B

C

B/C

A

B

A

B

A/B

B

B

A

A/B

A/B

A

B

B

C

C

A/B

B

C

A/B

A/B

B

A

A/B

A/B

A

A/B

A/B

A/B

A

A

A

B

B

B

A/B

B

A

C

fracturing

A

B

B

B

B

B

B

B

B

B

A

A
NUMBER 28 135

TABLE B.—Continued.

Specimen

number

ALHA77181f

ALHA77182

ALHA77184f

ALHA77186f

ALHA77187f

ALHA77188f

ALHA77193f

ALHA77195t

ALHA77201f

ALHA77202f

ALHA77205f

ALHA77207f

ALHA77213f

ALHA77220f

ALHA77227f

ALHA77228f

ALHA77235f

ALHA77237f

ALHA77240f

ALHA77242I

ALHA77245f

ALHA77247f

ALHA77253f

ALHA77259

ALHA77264

ALHA77265f

ALHA77266f

ALHA77268

ALHA77274

ALHA77275f

ALHA77279f

ALHA77287

ALHA77291f

ALHA77294

ALHA77300

ALHA78001+

ALHA78004*

ALHA78005+

ALHA78008

ALHA78010+

ALHA78012

ALHA78018+

ALHA78021

ALHA78023

ALHA78025+

ALHA78027*

ALHA78028

ALHA78031

ALHA78047*

ALHA78049+

ALHA78052*

ALHA78075

ALHA78079

ALHA78080

ALHA78081*

ALHA78085

ALHA78088*

ALHA78090*

ALHA78092*

Weight

(g)

33

1135

128

122

52

109

7

5

15

3

3

5

8

69

16

19

5

4

25

56

33

44

24

294

11

18

108

272

288

25

175

230

6

1351

235

85

36

28

7

1

38

18

17

10

8

29

4

5

130

96

97

281

5

25

18

219

5

8

16

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

Degree of

weathering

B

C

B

A/B

A/B

A/B

A

A

A

B

B

A/B

A

B

A

B

A/B

A

A

B

A/B

A/B

A/B

C

A/B

B

B

C

C

A

A

C

A

A

C

B

B

B

B

A

B

B

C

B/C

B

fracturing

B

B

A

C

A

A

A

B

B

B

B

B

Specimen

number

ALHA78094*

ALHA78096*

ALHA78098*

ALHA78102

ALHA78107

ALHA78108

ALHA78110

ALHA78111

ALHA78116*

ALHA78117+

ALHA78121*

ALHA78123+

ALHA78128

ALHA78129+

ALHA78136+

ALHA78139*

ALHA78141

ALHA78146

ALHA78150

ALHA78154+

ALHA78159

ALHA78160*

ALHA78163+

ALHA78164

ALHA78173+

ALHA78174+

ALHA78178+

ALHA78182

ALHA78190

ALHA78194

ALHA78197

ALHA78199

ALHA78201

ALHA78203

ALHA78205

ALHA78209

ALHA78217+

ALHA78219+

ALHA78221

ALHA78225

ALHA78227

ALHA78233

ALHA78241

ALHA78245

ALHA78247

ALHA78253+

ALHA78255+

ALHA78257+

ALHA78259+

ALHA79004

ALHA79006

ALHA79OO8

ALHA79009

ALHA79010

ALHA79011

ALHA79012

ALHA79013

ALHA79014

ALHA79015

Weight

(g)

4

7

2

337

198

173

161

127

128

4

30

18

155

128

52

17

24

17

16

12

23

16

10

25

20

13

7

10

20

25

20

13

10

11

9

12

8

8

5

5

2

1

7

4

3

7

3

2

6

35

41

12

76

25

14

192

28

11

64

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

Degree of

weathering

B/C

C

B

B/C

B/C

B

A

B

C

B

A

B

B

B

B

B

B/C

B

B

B

B

B/C

B/C

B

A

B

A

B/C

B/C

B

C

B/C

B/C

C

c

B

B

fracturing

B

A

B

B

A

B

B/C

B

A

A

B

B

B

B

B

A

B

A

B

B

A

B
136 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued.

Specimen

number

ALHA79021

ALHA79025

ALHA79026

ALHA79029

ALHA79031

ALHA79032

ALHA79036

ALHA79O38

ALHA79040

ALHA79041

ALHA79042

ALHA79046

ALHA79047

ALHA79048

ALHA79050

ALHA79051

ALHA79053

ALHA79054

ALHA80111

ALHA80123

ALHA80124

ALHA80127

ALHA80129

ALHA80132

ALHA81015

ALHA81019

ALHA81020

ALHA81033

ALHA81034

ALHA81036

ALHA81039

ALHA81042

ALHA81062

ALHA81063

ALHA81064

ALHA81067

ALHA81070

ALHA81071

ALHA81072

ALHA81075

ALHA81077

ALHA81080

ALHA81O81

ALHA81082

ALHA81083

ALHA81084

ALHA81088

ALHA81089

ALHA81090

ALHA81091

ALHA81100

ALHA81108

ALHA81110

ALHA81113

ALHA81115

ALHA81116

ALHA81118

ALHA81120

ALHA81124

Weight

(g)

29

1208

572

506

3

3

20

50

13

20

11

90

19

37

27

24

86

36

42

28

12

47

93

153

5489

1051

1353

252

255

252

206

534

0.5

5

191

228

4

2

3

16

4

17

5

6

7

16

4

11

10

12

155

69

3

111

155

2

85

14

9

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

De$

weathering

B

C

B

C

C

C

B

C

B

B

B

B

B

B

C

C

B/C

B

B

C

B

B

B

B

B

B/C

B

C

B

C

A/B

C

C

B/C

C

c

B/C

B

B/C

B

B

A/B

B

B

B

B

B

B

B

B

B

B

B/C

B/C

C

B

B/C

B/C

B

»ree of

fracturing

A

A

B

B/C

B

B

B

B

A

B

A

B

B

B

B

A

B

A

A

A

B

A

A

B

B

B

A

C

B

A

B

C

A

B

A/B

B

A

A

A

A

A

A

A

A

A

A

A

A

A

B

A

B

A

C

A/B

A

A

B

A

Specimen

number

ALHA81125

ALHA81126

ALHA81128

ALHA81129

ALHA8113O

ALHA81132

ALHA81133

ALHA81135

ALHA81136

ALHA81138

ALHA81139

ALHA81141

ALHA81143

ALHA81144

ALHA81148

ALHA81152

ALHA81155

ALHA81158

ALHA81161

ALHA81163

ALHA81164

ALHA81165

ALHA81166

ALHA81168

ALHA81169

ALHA81170

ALHA81171

ALHA81173

ALHA81175

ALHA81176

ALHA81178

ALHA81179

ALHA81182

ALHA81183

ALHA81186

ALHA81188

ALHA81192

ALHA81194

ALHA81195

ALHA81197

ALHA81201

ALHA81202

ALHA81207

ALHA81209

ALHA81211

ALHA81213

ALHA81215

ALHA81216

ALHA81218

ALHA81219

ALHA81220

ALHA81226

ALHA81227

ALHA81228

ALHA81230

ALHA81232

ALHA81233

ALHA81236

ALHA81237

Weight

(g)

10

22

16

32

30

5

21

10

1

4

7

1

13

3

13

10

5

2

122

82

20

6

26

8

6

59

24

26

13

95

30

14

5

104

23

9

9

17

5

68

7

5

14

14

7

3

11

2

6

24

3

3

11

8

13

5

25

41

27

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

Degree of

weathering

B

B

B/C

A/B

B

B

B

B

B

B

B/C

B/C

B/C

B

B

B

A/B

B/C

C

C

B

B

B

C

B

B

B/C

A/B

A/B

B

B/C

B

B

C

B

A/B

A/B

B

B

B/C

B/C

C

C

B/C

B

B/C

A

C

C

B

B/C

C

B

B/C

B

B

C

A/B

B

fracturing

A

A

A

A

B

A

A

A

A/B

A

B

B

A

A

A

A

A

A

C

B/C

A

A

A

B

B

A/B

B

A

B

A

B/C

A

A/B

B/C

A/B

A

A

B

A/B

B/C

A

A

B

A

A

A

A

A

B

A

A/B

A

B

A

B

A/B

B/C

A/B

B
NUMBER 28 137

TABLE B.—Continued.

Specimen

number

ALHA81238

ALHA81239

ALHA81240

ALHA81241

ALHA81242

ALHA81244

ALHA81245

ALHA81246

ALHA81249

ALHA81252

ALHA81255

ALHA81256

ALHA81263

ALHA81265

ALHA81269

ALHA81270

ALHA81274

ALHA81275

ALHA81276

ALHA81277

ALHA81281

ALHA81283

ALHA81284

ALHA81286

ALHA81287

ALHA81293

ALHA81294

ALHA81295

ALHA81296

ALH A81297

ALHA813OO

ALHA813O1

ALHA81302

ALHA81305

ALHA81306

ALHA81308

ALHA81314

ALH 82102

ALH 82103

ALH 82108

ALH 82109

ALH 82112

ALH 82114

ALH 82115

ALH 82119

ALH 82120

ALH 82122

ALH 82129

ALH 82134

ALH 82141

ALH 82144

EETA79OO7

EET 82603

EET 82604

EET 82614

EET 83200

EET 83203

EET 83208

META78010

Weight

(g)

24

32

41

34

20

5

4

3

10

2

12

28

6

8

5

4

19

11

42

7

46

0.6

10

28

78

2

9

105

13

20

10

12

4

1

7

19

3

48

2529

14

47

28

41

48

24

7

142

14

28

0.6

7

200

8210

1571

8

779

546

263

234

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

Degree of

weathering

C

B

C

B

B/C

B

B/C

C

B/C

B

B

C

B

B/C

B/C

C

A/B

B

C

B

B

B/C

B/C

B

C

B

B

C

B/C

B

A/B

B/C

B/C

B/C

B

B/C

B

B/C

B

B/C

B/C

C

A/B

A/B

B/C

B

B

B/C

B/C

C

B

B

B

B/C

A/B

B/C

B/C

B/C

B

fracturing

B

B

C

A/B

A

A

A/B

A

A

A

B

A

B

A

A

A/B

A

A

B

A

B

A

A

B

B/C

A/B

A

B/C

B

A

A

A

A

A

A

B

A

A

B

A

A/B

A

A

A

B

A

A

A

A

A

A

B

A

B

A

B

B/C

B

A

Specimen

number

PCA 82517

PC A 82521

PCA 82522

RKPA79004

RKPA79014

RKPA80210

RKPA80217

RKPA80218

RKPA80220

RKPA 80223

RKPA 80227

RKPA 80230

RKPA 80233

RKPA80236

RKPA 80240

RKPA 80243

RKPA 80244

RKPA80245

RKPA 80247

RKPA80249

RKPA 80250

RKPA 80251

RKPA 80257

RKPA80260

TIL 82409

TIL 82412

TIL 82413

TIL 82414

TIL 82415

ALHA78147*

ALHA76006

ALHA76008

ALHA77046f

ALHA77111t

ALHA77131t

ALHA77133f

ALHA77134f

ALHA77144

ALHA77146f

ALHA77147f

ALHA77148

ALHA77149f

ALHA77157f

ALHA77183

ALHA77200f

ALHA77209t

ALHA77212f

ALHA77239t

ALHA77246f

ALHA77248f

ALHA77258

ALHA77271

ALHA77285

ALHA77288

ALHA78002+

ALHA78035

ALHA78065+

Weight

(g)

41

1

46

371

78

11

8

7

124

25

8

58

414

16

61

3

14

37

1

10

4

29

9

8

231

35

18

15

70

31

271

281

8

52

26

19

19

8

18

19

13

26

88

288

0.9

32

17

19

42

96

597

610

271

1880

11

2

7

Class

and

type

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5

H5.6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

Degree of

weathering

B/C

C

B/C

B/C

B/C

B/C

C

c

B/C

c

B/C

B

B/C

B/C

C

c

c

B/C

C

B/C

B/C

B

B/C

C

B

C

C

B

A/B

C

B/C

A/B

A/B

A/B

A

A

B

A/B

A/B

C

A/B

A/B

C

C

B

A/B

B

B

B/C

B/C

C

c

c

A

B

fracturing

B

A

B

B

B

B

A

A

B/C

B

A

B

B

B

A

A

B

B

B

A

A

B

B

B

A

B

B

A

A

B

B

A

B

A

A/B

A

B

B
138 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued.

Specimen

number

ALHA78067

ALHA78069+

ALHA78076

ALHA78086*

ALHA78115

ALHA78122

ALHA78124

ALHA78135*

ALHA78137

ALHA78145+

ALHA78152

ALHA78169+

ALHA78184

ALHA78189

ALHA78191

ALHA78207

ALHA78211

ALHA78213

ALHA78215

ALHA78229

ALHA78231

ALHA78249

ALHA79002

ALHA79005

ALHA79016

ALHA79019

ALHA79020

ALHA79024

ALHA79028

ALHA79034

ALHA79037

ALHA79049

ALHA79055

ALHA8O118

ALHA80122

ALHA80126

ALHA8O13O

ALHA81035

ALHA81037

ALHA81O38

ALHA81054

ALHA81055

ALHA81076

ALHA81078

ALHA81079

ALHA81086

ALHA81093

ALHA81094

ALHA81096

ALHA81102

ALHA81103

ALHA81111

ALHA81112

ALHA81127

ALHA81134

ALHA81137

ALHA81146

ALHA81154

Weight

(g)

8

4

276

9

848

5

28

131

70

34

5

22

8

23

20

8

11

10

6

2

2

4

223

60

1146

12

4

22

16

13

15

54

15

2

50

35

5

256

320

229

2

5

10

6

7

6

271

152

83

196

136

210

150

15

15

9

24

1

Class

and

type

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

Degree of

weathering

B

B

B

B

A

B

B

B

B/C

B

B/C

C

B

B/C

B

B/C

C

B

B

B

C

B/C

B

B/C

A/B

B/C

C

B

C

B

B

B

B/C

C

B

A/B

C

B

B/C

B/C

B/C

B/C

B/C

B/C

B/C

C

B

fracturing

B

A

B

B

B

B

B

B

B

B

B

A

B

B

B

A

B

B

B

A

B

A

A

A/B

A

B

B

A

A

B

A

B

A/B

B

B

A/B

B/C

B

A

B

B

A/B

B

B

Specimen

number

ALHA81160

ALHA81180

ALHA81193

ALHA81196

ALHA81204

ALHA81210

ALHA81223

ALHA81224

ALHA81225

ALHA81248

ALHA81250

ALHA81253

ALHA81254

ALHA81268

ALHA81271

ALHA81273

ALHA81288

ALHA81291

ALHA81298

ALHA81303

ALHA81310

ALH 82113

ALH 82116

ALH 82124

ALH 82127

ALH 82138

ALH 82143

EET 82610

EET 82615

EET 83201

EET 83215

MBRA76001

MBRA76002

META78006

META78007

PCA 82512

PCA 82516

PCA 82523

PCA 82526

PCA 82527

RKPA79003

RKPA79009

RKPA79012

RKPA 80201

RKPA80203

RKPA80206

RKPA80208

RKPA 80211

RKPA 80213

RKPA 80214

RKPA80221

RKPA 80231

RKPA 80254

RKPA80255

RKPA80262

RKPA80265

RKPA80266

TIL 82405

Weight

(g)

12

17

13

9

7

0.6

10

14

14

5

17

10

9

18

28

43

20

4

16

4

0.7

61

18

26

5

5

3

42

29

1060

510

1096

13773

410

.175

55

16

11

25

3

182

55

13

813

4

47

10

2

19

5

52

238

68

7

32

8

10

1116

Class

and

type

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

Degree of

weathering

C

C

B

B

B

B

A/B

B/C

B

C

B

A/B

C

C

B

C

B

B

B

B/C

B

A/B

B

C

A/B

B

C

B

B

B/C

B/C

B

B

C

B/C

B

B/C

A

B

A

B

C

B

B

C

C

B

C

B/C

C

c

c

c

c

c

c

B/C

B

fracturing

B

B

A

A

A

A

A

A

A

A/B

B

B

A

B/C

B

B/C

A

A

B

A

A

A

B

A/B

A

A/B

A/B

A

A

A

C

B

B

B

B

A

B

B

A

A

A

B

B

A

A

B

A

B

B

B

B/C

B/C

B/C

B

B

B

B

A
NUMBER 28 139

TABLE B.—Continued.

Specimen

number

ALHA81174

ALHA77081

ALHA81261

ALHA81315

ALHA77011

ALHA77013f

ALHA77015

ALHA77031f

ALHA77033

ALHA77034f

ALHA77036f

ALHA77043f

ALHA77047f

ALHA77049f

ALHA77050f

ALHA77052f

ALHA77115f

ALHA77140

ALHA77160

ALHA77163I

ALHA77164

ALHA77165

ALHA77166f

ALHA77167

ALHA77170f

ALHA77175f

ALHA77176f

ALHA77178f

ALHA77185f

ALHA77197J

ALHA77211t

ALHA77214

ALHA77215

ALHA77216

ALHA77217

ALHA77241t

ALHA77244f

ALHA77249

ALHA77252

ALHA77260

ALHA77303f

ALHA78013

ALHA78017+

ALHA78037+

ALHA78038

ALHA78041+

ALHA78046

ALHA78119+

ALHA78133

ALHA78149+

ALHA78162+

ALHA78176+

ALHA7818O+

ALHA78186

ALHA78188

ALHA78235+

ALHA78236

ALHA78238

Weight

(g)

33

U

292

23

411

0.5

9

2

8

11

20

7

84

112

154

79

70

24

38

31

139

611

12

23

55

6

28

20

27

2111

820

1470

413

144

40

504

343

744

79

4

3

0.5

363

118

70

103

60

23

33

8

8

3

0.9

19

14

10

Class

and

type

H

"H(?)"

(Acapulcolike)

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

Degree of

weathering

B

B

A/B

A/B

C

B

C

B/C

C

B/C

B

B/C

C

B/C

B/C

B/C

B/C

C

C

B/C

C

C

C

c

B/C

B/C

B

B/C

A/B

A/B

B/C

C

B

A/B

B

C

B/C

C

B

C

B/C

B

B

C

B

A

B

B

B

B

C

B

fracturing

B/C

A

A

A

A

B

B

B

B

C

C

B/C

C

B/C

B/C

B/C

C

C

c

c

B

Specimen

number

ALHA78239+

ALHA78243

ALHA79001

ALHA79045

ALHA80133

ALHA81024

ALHA81025

ALHA81O3O

ALHA81031

ALHA81032

ALHA81053

ALHA81060

ALHA81061

ALHA81065

ALHA81066

ALHA81069

ALHA81085

ALHA81087

ALHA81121

ALHA81145

ALHA81156

ALHA81162

ALHA81190

ALHA81191

ALHA81214

ALHA81229

ALHA81243

ALHA81259

ALHA81272

ALHA81280

ALHA81292

ALHA81299

ALH83010

EET 82601

EET 83213

RKPA79008

RKPA80207

RKPA80256

ALHA79022

ALHA77230

ALHA77304

ALHA78044

ALHA78070

ALHA81040

ALHA81119

ALHA81184

ALH 83001

EET 82611

EET 82613

PCA 82514

RKPA80216

RKPA80242

TIL 82404

TIL 82406

TIL 82407

TIL 82411

TYR 82700

Weight

(8)

16

2

32

115

4

798

379

1852

1595

111

3

28

24

13

9

7

16

8

88

21

20

59

48

30

4

40

15

10

23

55

13

0.5

395

150

2727

73

18

153

31

2473

650

164

10

195

107

17

1569

13

4

130

44

7

322

152

221

180

892

Class

and

type

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3.4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

L4

Degree of

weathering

B

C

C

B

C

C

B/C

C

C

C

C

B/C

B/C

C

B/C

C

B/C

B

B

B/C

C

c

c

B/C

c

c

c

c

c

c

c

B

B/C

B

B

C

B

A/B

C

B

B/C

B/C

B

A/B

B

B

B

B

B

B/C

B

B

B/C

A/B

B

fracturing

A

B

B

B

B

B/C

B/C

A

B

B

A

B

B

A

B

B

B

B

B/C

C

A/B

B/C

A

B/C

B

B

B

B

A/B

A/B

A

A

A

B

B

A

B

B

B

B

A

B

A

A

B

A

A

B

B

B

A

A

A

A
140 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued.

Specimen

number

ALHA77002

ALHA77117f

ALHA77127f

ALHA77218f

ALHA77254

ALHA77267f

ALHA78142*

ALHA81017

ALHA81018

ALHA81023

ALHA81153

ALHA81198

ALH 82104

ALH 82107

ALH 82117

ALH 82137

EETA79009

PCA 82504

PCA 82505

PCA 82510

PCA 82513

PCA 82519

RKPA79013

RKPA 80209

RKPA 80228

RKPA80268

TIL 82400

ALHA76001

ALHA76003

ALHA76007

ALHA76009

ALHA77001

ALHA77008f

ALHA77019t

ALHA77026f

ALHA77027f

ALHA77089t

ALHA77150

ALHA77155

ALHA77l59f

ALHA77162f

ALHA77180

ALHA77198f

ALHA77231

ALHA77251f

ALHA77261

ALHA77269

ALHA77270

ALHA77272

ALHA77273

ALHA77277

ALHA77280

ALHA77281

ALHA77282

ALHA77284

ALHA77292

ALHA77293t

Weight

(g)

235

21

4

45

246

104

32

1434

2237

418

4

0.9

399

9

4

11

140

3094

3086

254

239

125

11

10

11

3

221

20151

10495

79

3950

252

93

60

20

4

8

58

305

17

29

191

7

9270

69

412

1045

589

674

492

143

3226

1231

4127

376

200

110

Class

and

type

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L5

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

Degree of

weathering

B

A/B

B

A

A/B

A

B

B

B

B

B/C

A

B/C

B

B

B

A/B

B

A

A/B

B

B/C

C

c

B/C

A/B

A

A

B

B

B

A

B/C

B/C

B/C

B

C

A/B

A/B

A

C

B

A/B

B

B

B

A/B

B/C

B

A/B

B

B

B

A/B

B

B

fracturing

A/B

A

A

B

A/B

A

A

A/B

A

B

A

B

B

B

A

A

A

B

B

B

B

B

A

A

A

B

B

B

A

A

A/B

B

A

B

B

B

A

B/C

B

B

B

A

Specimen

number

ALHA77296

ALHA77297

ALHA77301f

ALHA77305

ALHA78003

ALHA78039

ALHA78042

ALHA78043

ALHA78045

ALHA78048

ALHA78050

ALHA78055+

ALHA78059+

ALHA78074

ALHA78078

ALHA78101

ALHA781O3

ALHA78104

ALHA78105

ALHA78106

ALHA78112

ALHA78114

ALHA78125*

ALHA78126

ALHA78127

ALHA78130

ALHA78131

ALHA78156

ALHA78171+

ALHA78251

ALHA79007

ALHA79018

ALHA79027

ALHA79033

ALHA79043

ALHA79052

ALHA80101

ALHA8O1O3

ALHA80105

ALHA80107

ALHA8O1O8

ALHA80110

ALHA80112

ALHA8O113

ALHA80114

ALHA80115

ALHA80116

ALHA80117

ALHA80119

ALHA80120

ALHA80125

ALHA81016

ALHA81026

ALHA81027

ALHA81028

ALHA81029

ALHA81099

ALHA81106

ALHA81107

Weight

(g)

963

952

55

6444

125

299

214

680

39

191

1045

14

9

200

290

121

590

672

942

465

2485

808

19

607

195

2733

269

9

23

1312

142

121

133

281

62

23

8725

536

445

178

125

168

331

313

233

306

191

89

34

60

139

3850

516

3835

80

153

152

48

140

Class

and

type

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

Degree of

weathering

A/B

A

A

B/C

C

B

B

B

B/C

A/B

B

B

B

B

A/B

B

B

B

A/B

B

B/C

B

B

B/C

B/C

B/C

B

B

A/B

B/C

B

B

C

B/C

B

B

B

B

B

B

B

B

B

B

B/C

B

B

B

B/C

B

B

C

B

C

A/B

B

B

fracturing

A

B

B

B

B

A

B

B

B

B

B

A

B

A

A

A

B

B

B

B

B

B

A

A

B

A/B

A

A

B

B

B

A

B

B

B

B

B

B/C

B

A

B

A

B

B

B

A

A

A/B

B

A

A

B

A
NUMBER 28 141

TABLE B.—Continued.

Specimen

number

ALHA81122

ALHA81131

ALHA81150

ALHA81159

ALHA81167

ALHA81172

ALHA81181

ALHA81203

ALHA81205

ALHA81217

ALHA81221

ALHA81235

ALHA81247

ALHA81257

ALHA81262

ALHA81266

ALHA81278

ALHA81282

ALHA81289

ALHA81304

ALHA81307

ALHA81311

ALH 82105

ALH 82111

ALH 82118

ALH 82121

ALH 82123

ALH 82125

ALH 82139

ALH 82140

ALH 82142

ALH 83101

BTNA78001

BTNA78002

EETA79003

EETA79010

EET 82605

EET 82606

EET 82607

EET 82612

EET 83202

EET 83205

EET 83206

EET 83209

EET 83210

EET 83214

EET 83237

META78002

META78003

META78005

META78028

PCA 82503

Weight

(g)

21

13

2

10

59

33

15

4

3

5

9

7

104

29

55

12

1

31

4

42

57

0.9

363

63

111

2

111

178

0.2

0.3

20

639

161

4301

436

287

625

982

165

32

1213

471

462

520

426

1398

883

542

1726

172

20657

8308

Class

and

type

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

US

L6

L6

L6

L6

L6

L6

L6

L6

L6

L6

US

US

US

US

US

US

US

US

us

us

us

us

us

us

us

us

us

Degree of

weathering

B

A/B

C

B/C

B/C

C

B

C

B

C

C

C

A/B

B

A/B

A/B

B

A/B

A

A/B

B

B

A/B

A/B

A/B

A

B

C

B

C

C

A

B

B

B

B

B

B

B/C

A

A/B

A/B

B

B/C

A/B

B

B

B

B

B

B

A

fracturing

B

B

A

A

B

B

A

A

A

B/C

A/B

B

B

A

B

B

A

A

A

B

B/C

A

A

A

B

B

A

B

A

A

B/C

A

B

A

B

C

A

B

A

A

B

B

A

A

B

A

A/B

A

B

B

B

B

Specimen

number

PCA 82508

PCA 82509

PCA 82525

PCA 82528

RKPA78001

RKPA78003

RKPA79001

RKPA79002

RKPA80202

RKPA80215

RKPA80219

RKPA 80225

RKPA80252

RKPA80261

RKPA 80264

TIL 82401

ALHA78015*

ALHA76004

ALHA77278

ALHA78138+

ALHA79003

ALHA81251

TIL 82408

ALHA77060f

ALHA78109

ALHA81151

RKPA80234

RKPA 80253

ALHA77041f

ALHA78062

ALHA78063+

ALHA78082+

ALHA78153

ALHA81123

ALHA81185

ALHA81285

BTNA78004

EET 82608

EET 83204

PCA 82507

RKPA80222

RKPA80235

RKPA8O238

RKPA80248

TIL 82402

ALH 84027

Weight

(g)

389

286

40

51

235

1276

3006

204

545

9

21

8

11

62

24

282

35

53

313

11

5

158

80

64

233

5

136

5

17

11

77

24

152

2

65

20

1079

95

377

480

7

261

18

11

476

8

Class

and

type

L6

L6

L6

L6

US

US

US

US

US

US

US

L6

US

US

US

L6

LL(?L)3

LL3

LL3

LL3

LL3

LL3

LL3

LL5

LL5

LL5

LL5

LL5

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL7(?)

Degree of

weathering

A/B

B

B

B/C

C

C

B

B

B

C

B

C

A/B

B

B

A/B

A

A

B

B

B/C

B

A

A/B

B/C

B

A/B

A

A

A

B/C

B

A/B

C

B

A/B

A

A

B

A/B

A/B

A/B

A/B

B

fracturing

B

A

B

B

B

B

C

B

A

B

A

A

A

A

B

A

A

A

B

B

A/B

A

A

B

A

B

A

A/B

A

A

A

A

A/B

B

B

A

A

A

B
142 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued.

CHONDRITE subtotals: Class and type

C2

C3

C30

C3V

C4

E4

EH4

E5

E6

H3

H4

H4,5

H5

H5.6

H6

H

L3

L3.4

L4

L5

L6

LL(?L)3

LL3

LL5

LL6

LL7(?)

Total:

Class weight (g)

2680

181

810

748

103

31

159

20

819

433

83289

16000

42892

31

30305

33

23

19377

31

7149

12397

154434

35

619

443

3170

8

376220

Specimen •

number

ALHA81187

ALH 84025

ALHA81005

ALHA78113

ALH 83009

ALH 83015

ALH 84007

ALH 84008

ALH 84011

EET 83235

ALHA77256

ALH 84001

EETA79002

EET 83246

EET 83247

TIL 82410

ALH A81208

ALHA76005

ALHA77302

ALHA78040

ALHA78132

Weight

(g)

40

5

31

299

2

3

706

302

138

255

676

1931

2843

48

22

19

2

317

236

212

656

Class

and

type

A (unique)

A (unique)

Anorthositic

breccia

Au

Au

Au

Au

Au

Au

Basaltic

achon.

Di

Di

Di

Di

Di

Di

Di/M

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Degree of

weathering

B/C

A/B

A/B

A/B

A/B

A/B

A

A/B

A

B

A/B

A/B

B

A/B

B/C

A

C

A

A

A

A

fracturing

ACHC

B

A

A

A

A

A

A/B

A

A/B

B

A

B

B

A/B

B

B

A

A

A

A

)N

Specimen

number

T3RITES

ALHA78158

ALHA78165

ALHA79017

ALHA80102

ALHA81001

ALHA81006

ALHA81007

ALHA81008

ALHA81OO9

ALHA81010

ALHA81011

ALHA81012

ALHA81313

EETA79004

EETA79005

EETA79011

EET 83212

EET 83227

EET 83228

EET 83229

EET 83231

EET 83232

EET 83234

EET 83236

EET 83251

EET 83283

PC A 82501

PCA 82502

RKPA80204

RKPA 80224

Weight

(g)

15

21

310

471

53

255

164

44

229

219

406

37

0.5

390

451

86

402

1973

1206

313

66

211

181

6

261

57

54

890

15

8

Class

and

type

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (anomalous)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu

Eu (polymict)

Eucritic breccia

Eu

Eu(?)

Eu

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu

Eu (polymict)

Eu (polymict)

Eu (unbrecciated)

Eu (unbrecciated)

Eu

Eu (unbrecciated)

Degree of

weathering

A

A

A

A

A

A

A/B

A/B

A

A

A/B

A/B

B

A

B

B

B

B

B

B

B

B

B

B

B

A

A

A

A/B

fracturing

A

A

A

B

B

A/B

A

A/B

A

A

A

A

B

B

B

B

B

B

B

A/C

A/B

B

A

A/B

B

A

A

A

A
NUMBER 28 143

TABLE B.—Continued.

Specimen

number

RKPA 80224

TIL 82403

ALHA78006

EETA79006

EET 82600

ALHA77005

EETA79001

Weight

(8)

8

50

8

716

247

483

7942

Class

and

type

Eu (unbrecciated)

Eu (brecciated)

Ho

Ho

Ho

Sh

Sh

Degree of

weathering

A/B

A

A

B

A

A

A

fracturing

A

A

A

B

B

A

A

Specimen

number

ALHA77257

ALHA78019

ALHA78262

ALHA81101

ALH 82106

ALH 82130

ALH 83014

EET 83225

PCA 82506

RKPA 80239

Weight

(8)

1996

30

26

119

35

45

1

44

5316

6

Class

and

type

Ur

Ur

Ur

Ur

Ur

Ur

Ur

Ur

Ur

Ur

Degree of

weathering

A

B/C

B/C

A/B

B

B

B

B/C

A/B

B

fracturing

B

C

A

B

A

A

A

B

A

B

ACHONDRITE subtotals: Class and type

A (unique)

Anorthositic breccia

Aubrite

Basaltic breccia

Diogenite

Diogenite/Mesos.

Eucrite

Howardite

Shergottite

Ureilite

Total:

Class weight (g)

45

31

1449

255

5540

2

10266

971

8425

7618

34602

Total weight (g): 324743

Specimen

number

ALHA77255

ALHA80104

EET 83230

ILD 83500

ALHA81013

ALHA81014

EET 83245

RKPA80226

ALHA76002

ALHA77250

ALHA77263

ALHA77283

ALHA77289

Weight

(8)

765

882

530

2523

17727

188

59

160

307

10555

1669

10510

2186

Class

and

type

Ataxite (anom)

Ataxite

Ataxite

Ataxite

Hexahedrite

Octahedrite

Octahedrite

Octahedrite

IA

IA

IA

IA

IA

Degree of

weathering fracturing

I

Specimen

number

)NS

ALHA77290

PGPA77006

ALHA78100

DRPA78001

DRPA78002

DRPA78003

DRPA78OO4

DRPA78005

DRPA78006

DRPA78007

DRPA78008

DRPA78009

ALHA78252

Weight

(8)

3784

19068

85

15200

7188

144

134

18600

389

11800

59400

138100

2789

Class

and

type

IA

IA

IIA

IIB

IIB

IIB

IIB

IIB

IIB

IIB

IIB

IIB

IVA

Degree of

weathering fracturing

Specimen

number

ALHA77219

ALHA81O59

ALHA81098

RKPA79015

Weight

(8)

637

540

71

10022

Class

and

type

M

M

M

M

Degree of

weathering

B

C

C

A/B

fracturing

STOI

B

B/C

B/C

A

Specimen

number

r

-lRON

RKPA 80229

RKPA80246

RKPA80258

RKPA80263

Total weight (g): 11311

Weight

(8)

14

6

4

17

Class

and

type

M

M

M

M

Degree of

weathering

C

C

B/C

C

fracturing

B/C

C

B

B
144 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE C.—Meteorites tentatively identified as paired specimens from common falls. Pairing criteria are field

relations (t), megascopic physical similarities (v), petrographic and mineral chemical similarities (w),

metallography (x), bulk chemistry (y), and trace element chemistry (z). This list is restricted to paired groups

listed in the Antarctic Meteorite Newsletters and which are assigned pairing confidence levels of over 50% by

Scott (Chapter 13). For a more comprehensive discussion of the pairing problem, and a more inclusive list of

pairings, see Scott (Chapter 13) and Scat (1984)*.

Pair no. Paired specimens Criteria

9

10

11

12

13

14

15

16

17

18

ALH83009, 83015

AUB RITES

EUCRITES

ALHA81009, 81012

ALHA76005, 77302, 78040, 78132, 78158, 78165, 79017, 80102

ALHA81006, 81007, 81008, 81010

EETA79004, 83228

v,w

v,w

v,w

v,w

w

EETA79006, 82600

ALHA78019, 78262

ALH82106, 82130

ALHA81002, 81004

ALH83100, 83102

ALHA77003, 82101

HOWARDITES

UREILITES

C2 CHONDRITES

C30 CHONDRITES

V,W

w

C3V CHONDRITES

ALHA81OO3, 81258 w

EH4 CHONDRITES

ALHA77156,77295 w

E6 CHONDRITES

ALHA81021, 81260 w

"H?" CHONDRITES (Acapulco-like)

ALHA77081,81261,81315 w

H4 CHONDRITES

ALHA77004, 77190, 77191, 77192, 77208, 77223, 77224, 77225, 77226, 77232, t.w

77233

ALHA78193, 78196, 78223 t,x

ALHA81041, 81043, 81044, 81045, 81046, 81047, 81048, 81049, 81050, 81051, w

81052

•Scott, E.R.D. 1984. Pairing of Meteorites Found in Victoria Land, Antarctica. Memoirs of the National

Institute of Polar Research (Japan), special issue, 35:102-125. Tokyo.
NUMBER 28 145

TABLE C.—Continued.

Pair no. Paired specimens Criteria

H5 CHONDRITES

ALHA77014, 77264

ALHA77021,77025,77061,77062,77064,77071, 77074,77086,77088

ALHA77118, 77119,77124

ALHA78209, 78221, 78225, 78227, 78233

ALHA79031,79032

ALHA80127, 80129, 80132

RKPA80217, 80218

RKPA80220, 80223

RKPA 80250, 80251

TIL82412, 82413

TIL82414, 82415

H6 CHONDRITES

MBRA76001,76002

ALHA77144, 77148

ALHA77271, 77288

ALHA78211, 78213, 78215, 78229, 78231

ALHA80122, 80126, 80130

ALHA81O35, 81038, 81103, 81112

RKPA80203, 80206, 80208, 80211, 80213, 80214, 80221, 80231, 80254, 80255,

80265, 80266

EET82610, 82615

PCA82526, 82527

L3 CHONDRITES

ALHA77011, 77015, 77031, 77033, 77034, 77036, 77043, 77047, 77049, 77050,

77052,77115,77140,77160,77163,77164,77165, 77166,77167,77170, 77175,

77178,77185, 77211,77214,77241, 77244,77249, 77260,77303,78013, 78038,

78186, 78188, 78236, 78238,78243, 79001, 79045, 80133, 81025, 81030, 81031,

81032, 81053, 81060, 81061, 81065, 81066, 81069, 81085, 81087, 81121, 81145,

81156, 81162, 81190, 81191, 81214

ALHA77215, 77216, 77217, 77252

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

RKPA80216, 80242

ALHA81017, 81018, 81023

PCA82504, 82505

L4 CHONDRITES

L5 CHONDRITES

L6 CHONDRITES

ALHA77001, 77292, 77293, 77296, 77297

ALHA78043,78045

ALHA78103, 78105

ALHA80101, 80103, 80105, 80107, 80108, 80110, 80112, 80113, 80114, 80115,

80116, 80117, 80119, 80120, 80125

ALHA81027, 81028, 81029

BTNA78001, 78002

RKPA78001, 78003

RKPA79001, 79002, 80202, 80219, 80225, 80252, 80261, 80264

EET82605, 82606

t

t,w

t

t,x

w

w

w

w

w

w

w

w

t

t

t,x

w

t.v.w

t,v,w

w

t,w

v,w

w

v,w
146 SMITHSONIAN CONTRIBUTIONS TO TH E EARTH SCIENCES

TABLE C.—Continued.

Pair no. Paired specimens Criteria

LL3 CHONDRITES

53 ALHA76004,81251 w

LL6 CHONDRITES

54 RKPA80222,80238,80248 w

MESOSIDERITES

55 RKPA79015,80229, 80246,80263 w

56 ALHA81059,81098 w

IRONS

57 ALHA76002,77250,77263,77289,77290 t,x,y,z

58 DRPA78001,78002, 78003, 78004, 78005, 78006, 78007, 78008,78009t t,v,x,y

tSeven additional specimens (DRPA78010-78016), collected at the same time from the same small area,

are believed by all workers to be included in this pairing even though they have not been studied in detail. See

Scott (Chapter 13) and Clarke, R.S., Jr. 1982. The Derrick Peak, Antarctica, Iron Meteorites. Meteoritics,

17:129-134.

. GOVERNMENT PRINTING OFFICE: 1989-181-717/60033