SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES • NUMBER 26

Field and Laboratory

Investigations of Meteorites

from Victoria Land, Antarctica

Ursula B. Marvin

and Brian Mason

f

 EDITORS

f

i

i -.

ISSUED

JUN8 1984

SMITHSONIAN PUBLICATIONS

SMITHSONIAN INSTITUTION PRESS

City of Washington

1984
ABSTRACT

Marvin, Ursula B., and Brian Mason, editors. Field and Laboratory Investigations of Meteorites from Victoria Land, Antarctica. Smithsonian Contributions to the Earth Sciences, number 26, 134 pages, frontispiece, 79 figures,

11 tables, 1984.—This monograph describes the meteorite collecting activities in Victoria Land during the 1980-1981 and 1981-1982 field seasons,

and the geodetic measurements of ice motion and ablation at the Allan Hills

site. Descriptions and classifications are given for all specimens collected

during the 1980-1981 season and for most of those collected during the

1981-1982 season. Review articles are included on the petrology and classification of 145 small meteorites collected in the 1977-1978 season, on

Antarctic Type 3 chondrites, and on cosmic-ray-produced nuclides in the

Victoria Land meteorites. The first lunar meteorite is described. Chemical

analyses of 25 Victoria Land meteorites are published, with a discussion of

Antarctic weathering effects. The Appendix lists all of the Victoria Land

meteorites classified as of June 1983, by numerical order for each locality

and by meteorite class.

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

Main entry under title:

Field and laboratory investigations of meteorites from Victoria Land, Antarctica.

(Smithsonian contributions to the earth sciences ; no. 26)

Bibliography: p.

1. Meteorites—Antarctic regions. I. Marvin, Ursula B. II. Mason, Brian Harold, 1917-

III. Series.

QE1.S227 no. 26 [QB755.5A] 550s [523.5'1] 83-20087
Contents

Page

EDITOR'S INTRODUCTION, by Ursula B. Marvin and Brian Mason ... . 1

T HE 1980-1981 FIELD SEASON, by William A. Cassidy 5

T HE FIELD SEASON IN VICTORIA LAND, 1981-1982, by R.F. Fudali and

J.W. Schutt 9

ABLATION AND ICE MOVEMENT AT THE ALLAN HILLS MAIN ICEFIELD

BETWEEN 1978 AND 1981, by Ludolf Schultz and John O.

Annexstad 17

DESCRIPTIONS OF STONY METEORITES, by Roberta Score, Carol M.

Schwarz, and Brian Mason 23

DESCRIPTIONS OF IRON METEORITES AND MESOSIDERITES, by Roy S.

Clarke, Jr 49

PETROLOGY AND CLASSIFICATION OF 145 SMALL METEORITES FROM THE

1977 ALLAN HILLS COLLECTION, by Susan G. McKinley and

Klaus Keil 55

CLASSIFICATION, METAMORPHISM, AND BRECCIATION OF TYPE 3 CHONDRITES FROM ANTARCTICA, by Edward R.D. Scott 73

A METEORITE FROM THE MOON, by Ursula B. Marvin 95

COSMIC-RAY-PRODUCED NUCLIDES IN VICTORIA LAND METEORITES, by

Kunihiko Nishiizumi 105

BULK CHEMICAL ANALYSES OF ANTARCTIC METEORITES, WITH NOTES

ON WEATHERING EFFECTS ON FEO, FE-METAL, FES, H2O, AND C, by

Eugene Jarosewich Il l

APPENDIX: Tables of Victoria Land Meteorites 115

in
Allan Hills 81005, the first lunar rock to be discovered on the surface of Earth. Photograph

taken before processing at the Curatorial Facility in the NASA Johnson Space Center at

Houston.
Field and Laboratory

Investigations of Meteorites

from Victoria Land, Antarctica

Editors' Introduction

Ursula B. Marvin and Brian Mason

This is the third publication in the Smithsonian Contributions to the Earth Sciences series

to review the results of the yearly United States

expeditions to collect meteorites in Victoria

Land, Antarctica. The first two publications

were Catalog of Antarctic Meteorites, 1977-1978

(Marvin and Mason, 1980) and Catalog of Meteorites from Victoria Land, Antarctica, 1978-

1980 (Marvin and Mason, 1982). Both publications were much more than catalogs. They

included descriptions of field and laboratory

investigations and overview articles on the

more interesting types of Antarctic meteorites.

This third publication in the series continues

this practice and so we have dropped the word

"Catalog" from the title.

This issue describes the 1980-1981 and

1981-1982 field seasons in Victoria Land. It

contains chapters outlining the results of the

first geophysical measurements of ice thickness

and the continuing geodetic measurements of

ablation and ice motion in the Allan Hills reUrsula B. Marvin, Smithsonian Astrophysical Observatory, 60

Garden Street, Cambridge, Massachusetts 02138. Brian Mason, Department of Mineral Sciences, National Museum of

Natural History, Smithsoniati Institution, Washington, B.C.

20560.

gion. All specimens weighing more than 100

grams, collected in those two seasons, are described and classified. In addition, the classifications of several groups of smaller, pebblesized specimens, collected in the 1977-1978

season, have been added to the updated lists

in the Appendices. Appendix Table A lists all

of the Victoria Land meteorites, classified by

May 1983, for each locality by consecutive

numbers; Appendix Table B lists specimens

consecutively by meteorite class; and Appendix

Table C lists the specimens currently believed

to be paired. One chapter reviews new observations on the rare and relatively primitive

Type 3 chondrites from Antarctica; another

presents the latest measurements of cosmogenic nuclides and terrestrial ages of Antarctic

meteorites. A computerized Antarctic Meteorite Bibliography is maintained at the Lunar

and Planetary Institute (3303 NASA Road 1,

Houston, Texas 77058) and lists of publications from it are available on request.

The highlight of the Antarctic collecting

program is the discovery, on the final day of

the 1981-1982 field season, of the first lunar

sample ever to be found on the surface of the

Earth. A brief account is presented of the field

1
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

occurrence and initial characterization of this

specimen.

The total numbers and classifications of meteorite specimens collected in the 1980-1981

and 1981-1982 seasons are listed in Table 1.

After six successive seasons of searches, the

Main Icefield at the Allan Hills region still

yields new specimens yearly, and exploration

has barely begun of the vast reaches of blue

ice in the Middle Western and Far Western

icefields. (For the configuration of these fields

see Marvin, herein, p. 96.) During preparation

of this publication, we received news that reconnaissance work in the 1982-1983 season

revealed the presence of rich new lodes of

specimens in the area of the Thiel Mountains

(Figure 1). The fruitfulness of the Antarctic

Meteorite Program is thus assured for the foreseeable future.

The field explorations and laboratory research are both increasingly international in

TABLE 1.—Numbers of meteoritic specimens collected

in the 1980-1981 and 1981-1982 (in parentheses) seasons.

Class

Chondrites

Carbonaceous

chondrites

Achondrites

Mesosiderites

Irons

Totals

Allan

Hills

30 (355)

0 (4)

1 (10)

0 (2)

1 (2)

32 (373)

Reckling

Peak

60

0

2

4

1

67

Outpost

Nunatak

1

0

0

0

0

1

Totals

91

0

3

4

2

100

Antarctica

KEY;

— Continental Boundary

" — Ice Shelf Border

; = * Major Glaciers

• Meteorite Find

500 km

FIGURE 1.—Map of Antarctic meteorite finds. Four meteorites were discovered before the

beginning of the current program: Adelie Land, 1912; Lazarev, 1961; Thiel Mountains, 1962;

and Neptune Mountains, 1964. Meteorite concentrations were discovered by a United States

party in the Thiel Mountains during the 1982-1983 season.
NUMBER 26

scope. The Japanese program has just completed its eighth season, working out of Syowa

Base in the regions of the Yamato and Belgica

Mountains. Japanese scientists also spent three

seasons with the United States field parties in

Victoria Land. The United States program,

led by William A. Cassidy of the University of

Pittsburgh, began work in Antarctica in 1976

and has spent seven seasons conducting

searches along the interior flank of the

Transantarctic Range at sites within helicopter

range of McMurdo Station. The United States

field parties have included members from Japan, West Germany, Denmark, and Switzerland, and future teams are expected to include

members from Australia and other countries.

Specimens from the United States collections

have been distributed to at least ninety research laboratories in thirteen countries.

Approximately 7000 specimens, most of

them weighing only a few grams, have been

collected in the past ten years by the Japanese

and United States scientists. These specimens

are important not for their numbers but because they include new varieties of meteorites,

which have not been found on other continents, and additional specimens of certain very

rare species. Furthermore, isotopic measurements of terrestrial residence times show that

the Antarctic specimens landed on the Antarctic ice sheet between 10,000 and 700,000 years

ago, with some fall dates clustering between

100,000 and 400,000 years. Most meteorites

collected on other continents fell within the

past 200 years, although a few stones fell as

early as 20,000 years ago. Thus, the Antarctic

ice sheet is furnishing us with a somewhat older

sample of the stony materials that have followed Earth-crossing orbits. These results have

aroused the interest of glacial geologists, who

are examining the relationship between meteorite concentrations on bare icefields and the

age and flow patterns of the ice in the catchment areas. The Antarctic occurrences have

prompted Canadian and Danish scientists to

explore for similar meteorite concentrations in

the Canadian Arctic and Greenland.

The United States Antarctic Search for Meteorites (ANSMET) is governed by an interagency agreement between the National Science Foundation, the Smithsonian Institution,

and the National Aeronautics and Space Administration. Procedures have been developed, based loosely on those followed by the

Apollo astronauts, for collecting the specimens

by sterile techniques and keeping them frozen

until they are processed in nitrogen-filled glove

cabinets at the Johnson Space Center in Houston. Details of the field and laboratory procedures are outlined in the first publication in

this series (Marvin and Mason, 1980). With the

intent of distributing research samples quickly

and widely, all newly classified specimens are

described in the Antarctic Meteorite Newsletter

and 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 samples 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 sample 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.

Libraries of polished thin sections have been

established in Washington, Houston, and Tokyo for the use of visitors who wish to make

microscopic examinations. The library thin

sections are not available for loan. To obtain
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

meteorite samples from the Japanese collections or to use the thin section library in Tokyo, contact T. Nagata, Director, or K. 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 in Houston, contact the Secretary of the Meteorite

Working Group at the address given above.

To make arrangements for using the library at

the National Museum of Natural History,

Smithsonian Institution, Washington, D.C.

20560, contact Brian Mason, 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.

Marvin, Ursula B., and Brian Mason, editors

1982. Catalog of Meteorites from Victoria Land,

Antarctica, 1978-1980. Smithsonian Contributions to the Earth Sciences, 24: 97 pages.
The 1980-1981 Field Season

William A. Cassidy

The 1980-1981 field season was the fifth

enterprise supported by the National Science

Foundation in as many years. Beforehand, we

knew that in addition to the Main Icefield

(76°42'S, 159°20'E) at Allan Hills, where the

existence of a large meteorite concentration

had been proved, lesser concentrations of meteorites could be found at the Near Western

Icefield (76°40'S, 158°49'E), Reckling Moraine (76°08'S, 158°47'E), and Elephant Moraine (76°14'S, 157°11/E). We were eager to

investigate new sites in the hope of locating

additional concentrations that could be exploited during future field seasons. We therefore devoted as much time as possible to reconnaissance and as little time collecting meteorites at known sites as was necessary to assure a

successful season.

After collecting 32 specimens at Allan Hills

we traversed to Reckling Moraine, where we

recovered 67 specimens. Reckling Moraine

(Figure 2) is an extensive ice-cored detrital

rock deposit with no outcropping source in the

upstream direction. The source of the moraine

rocks therefore may be an elevated segment of

an underlying east-west ridge whose surface

expression on the ice is a step feature associated with the Reckling Moraine Icefield. This

icefield averages 3-5 km in width and extends

about 100 km in the east-west direction. Elephant Moraine is located about 50 km to the

William A. Cassidy, Department Geology and Planetary Science, University of Pittsburgh, Pittsburgh, Pennsylvania

15260.

west, along the same icefield. It may be that

the sites of highest meteorite concentration

along this icefield are at or near these moraines. These, in turn, could result from a

more sluggish flow of ice over the subsurface

barriers that produce these moraines. As we

have seen at Allan Hills and Yamato Mountains, meteorite concentrations tend to occur

at sites where ice flow is sluggish or stagnant.

Approaching the icefield at Reckling Moraine from the south, we had to lower our

supply-laden Nansen sledges down the 15°-

20° face of the step feature by using snowmobiles in tandem: one at the rear, braking to

stabilize the sledge, and one in front, pulling

gently to keep its heading true. As in our

previous visit, we followed the same route

across the step feature as the one first used by

the Philip Kyle party in December 1978. At

the bottom of the step feature we were on the

main part of the Reckling Icefield.

Prevailing wind direction is generally southwesterly across the narrow dimension of the

icefield. Most of the 67 specimens we recovered were small (20-100 g) individuals or

fragments found near the firn-ice boundary

along the northern edge of the icefield. Presumably these are small enough to have been

blown across the ice surface by strong winds,

then trapped against snow and firn at the

northern edge of the ice.

While at Reckling Moraine we received an

air-drop of eight drums of snowmobile fuel to

enable us to extend our traverse to points

farther to the north: these included ice expo-
SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 2.—Oblique photo looking westward at Reckling Moraine from a point above Reckling

Peak. Smooth gray areas are patches of exposed ice. Lighter gray areas are snow. In some

places the snow surface appears rough due to the presence of snow dunes (sastrugi). Near the

center of the photo is a sinuous feature having the gray of exposed ice but with a rougher

surface. This is Reckling Moraine. That part of the exposed ice that looks like a line of low

hills and which tends to mimic the irregular boundary of the moraine is the step feature

referred to in the text.

sures associated with Griffin Nunatak (Figure

3), Brimstone Peak, Tent Rock, and Sheppard

Rocks. We hoped to augment the minimum

collection we had made so far with additional

recoveries from new concentration areas, but

in this we were to be disappointed. A single

small specimen was found at Outpost Nunatak,

an outlier of Griffin Nunatak, but none were

found at the other sites; thus it was well illustrated that not all fields of exposed ice can be

expected to produce meteorite concentrations.

At these barren localities we were relatively

close to an area of fast-moving ice at the head

of the David Glacier. In addition, the icefields

are located downstream of the outcrops; therefore, the ice probably is migrating toward the

head of the David Glacier unimpeded by intervening barriers. In these areas, too, wind direction was such that snow was piled against

the upstream sides of the barriers, so that ice

ablation was not occurring in the stagnant flow

regimes where meteorite stranding would be

favored. The net result of our reconnaissance

efforts during the 1980-1981 field season was

a greater understanding of the conditions under which meteorite surface accumulations occur, and do not occur.

In other activities during the 1980-1981

season, we obtained new measurements of

ablation rates at our Allan Hills triangulation

network (Cassidy and Annexstad, 1981), and

one member of our party devoted considerable

time to foot searches for meteorites in Taylor

Valley, with negative results. This is of interest

because certain surfaces in the Dry Valleys,

(77°-78°S, 160°-163°E) are expected to be

rather ancient and one would not be surprised

to find accumulations of meteorites that had
NUMBER 26

tmWk

FIGURE 3.—Camp at Griffin Nunatak, 30 km north of Reckling Peak. Part of the nunatak

forms the rock cliff in the background.

fallen on them and been preserved in the dry

environment. Mechancial erosion, however,

may be more efficient in the Dry Valleys than

on the icefields farther inland. Alternatively,

TABLE 2.—The 1980-1981 collection.

Chondrites

Carbonaceous

chondrites

Achondrites

Mesosiderites

Irons

Totals

Allan

Hills

30

0

1

0

1

32

Reckling

Peak

60

0

2

4

1

67

Outpost

Nunatak

1

0

0

0

0

1

the Dry Valley surfaces may be less ancient

than has been believed.

The classification of meteorites recovered

during the 1980-1981 season is given in Table

2.

Expedition members were W.A. Cassidy,

J.O. Annexstad, J. Schutt, L.A. Rancitelli, L.

Schultz, H. McSween, and J. Danielson. This

work was supported by NSF/DPP 78-21104

and is Departmental Contribution 572.

Literature Cited

Annexstad, J.O. and W.A. Cassidy

1981. Antarctic Search for Meteorites, 1980-1981.

Antarctic Journal of the United States, 16(5):61-

62.
The Field Season in Victoria Land, 1981-1982

R.F. Fudali andJ.W. Schutt

The 1981-1982 field season in Victoria

Land was, by any measure, highly successful.

Major accomplishments included a second resurvey of the established triangulation network, the recovery of 378 meteorite specimens, and a gravity survey to model the icebedrock interface, all at the Allan Hills, South

Victoria Land (76°45'S, 159°40'E). Further,

advantage was taken of logistic support provided by a season-long field camp in North

Victoria Land (72° 12'S, 163°50'E) to conduct

reconnaissance meteorite searches in this new

area and to examine a possible small meteorite

crater at Littel Rocks (7l°23/S, 162°0/E).

The team was led again by William Cassidy,

University of Pittsburgh. Other participants

were John Annexstad, NASA Johnson Space

Center; Ghislaine Crozaz, Washington University at St. Louis; Ursula Marvin, Smithsonian

Astrophysical Observatory; Ludolf Schultz,

Max Planck Institute for Chemistry; and the

authors.

Annexstad and Schultz spent the period 15

November to 13 December determining horizontal and vertical displacements of their triangulation stations for the second time since their

emplacement. They also continued their yearly

measurements of ice ablation rates (see Schultz

and Annexstad, herein, or Cassidy and Annexstad, 1981). These tasks were accomplished

R.F. Fudali, Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington,

D.C. 20560. I. W. Schutt, Department of Geology and Planetary Sciences, University of Pittsburgh, Pittsburgh, PA 15260.

despite long stretches of extremely bad

weather, which, however, did prevent them

from extending the network further west.

The authors spent 24 November to 15 December at the North Victoria Land (NVL)

camp, 600 km north of McMurdo Station near

the head of the Canham Glacier. Here the

camp scientists were supported by a number

of snowmobiles and three HU-1N helicopters.

Air photos of the region, on file at USGS

Headquarters in Reston, Virginia, were used

to delineate a number of promising bare ice

areas within helicopter range of the NVL

camp. The crater at Littel Rocks was also

found during this archival search.

The reconnaissance in NVL was largely by

helicopter, but it was necessary to make rather

frequent ground checks because of the unanticipated litter of terrestrial rubble on many of

the bare ice surfaces. Bare ice patches at the

Lonely One Nunataks, Reniere Rocks, Emlen

Peaks, Outback Nunataks, Johannsen Nunatak, Frontier Mountan, Onlooker Nunatak,

and Monument Nunatak were examined. Icefields in the southern and western regions of

the Daniels range were also overflown and a

snowmobile traverse to the ice patches near

the Gallipoli Heights was undertaken. No meteorites were found during any of these

searches; because of the terrestrial rocks littering many of these surfaces we cannot categorically say there are no meteorites present.

However, it is clear that there can be no large

meteorite concentrations such as those at the

Allan Hills and the Yamato Mountains. Most

9
10 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

of the meteorites found to date in Antarctica

have been on ablation surfaces upstream of

rock barriers to ice flow. In the areas accessible

by helicopter from the NVL camp there appear to be no such upstream icefields. Rather

there are a number of fast-moving glacial systems without extensive areas of stagnant ice.

The terrestrial rocks littering many of these

bare ice surfaces in the vicinity of outcropping

bedrock presumably indicates these surfaces

are moving away from, rather than toward,

the potential rock barriers. In general then,

such rock litter may prove to be a strong

contraindication of meteorite concentrations,

and future reconnaissance in new areas should

be conducted with this in mind. Unfortunately,

the size range of the rock litter is far too small

to be detected on air photos. Whether or not

there are other subtle diagnostic features on

the air photos that would permit us to distinguish stagnant from moving icefields is a question we have not yet answered. The utility of

being able to make such distinctions is obvious;

an important step in addressing the question is

searching apparently promising icefields and

finding no meteorite concentrations. So our

negative findings at NVL may well prove more

useful, in the long run, than if we had found

meteorites there.

One day was spent examining the circular

"crater" at Littel Rocks. The depression is

about 125 m in diameter and has a terrace

partially incised inside its bowl, about 5 m

above the floor. The depression would be a

closed basin of deposition for water, but it has

clearly been overidden one or more times in

the past by ice. We surmise that the terrace

represents the former water level of a shallow

lake and was sculpted by moving ice when the

lake was frozen. There are other such shallow

lakes in the area although none are so circular

as this example. In any case we found no

evidence of a meteoritic origin—in fact quite

the contrary. Littel Rocks is composed of a

dolerite intrusion characterized by a very

strong, narrowly spaced, vertical joint system.

This vertical jointing can be observed, undisturbed, in the floor of the depression; i.e.,

there is no rubble zone beneath the present

floor and the depression is much too shallow

(10-15 m) to contemplate the removal of such

a rubble zone by eroding ice. We therefore

conclude that the depression is not an impact

crater and is most likely the result of glacial

activity.

The amenities of a season-long Antarctic

field camp, such as the NVL establishment,

have been described in some detail by Marvin

(1982) and will not be repeated herein. Suffice

it to say that one of us (RFF) was quite prepared to not find meteorites throughout the

balance of the field season at NVL until advised that this was not a permissible option.

In contrast to the areas searched in NVL,

meteorites were still readily found on the bare

ice patches west of the Allan Hills. A party

consisting of Cassidy, Crozaz, Marvin, and the

authors spent 33 days in this area (22 December 1981 through 23 January 1982).

The Allan Hills icefields comprise five separate bare ice areas (Figure 4). The Main Icefield extends NNW from Peak 2330 for nearly

22 km and contains roughly 75 km2 of blue

ice. The Near Western Icefield, 18 km west of

Peak 2330, contains about 14 km2 of blue ice.

The Middle Western Icefield, 31 km WSW of

Peak 2330, contains about 30 km2 of blue ice.

The Far Western Icefield (not shown on Figure 4) is a vast area of blue ice, over 40 km

long and 2-8 km wide, with an area in excess

of 100 km2. Its southeastern end is some 70

km WSW of Peak 2330. Because of poor

weather and insufficient time, a planned reconnaissance of the Far Western Field during the

1981-1982 season was not attempted. The

Battlements Icefield, slightly smaller than Middle Western Field, had not been examined

previously, primarily because of the very difficult terrain immediately south of Battlements

Nunatak. This season our party reached the

nunatak and found a passage through it to the

icefield. A cursory examination of the ice surface revealed it to be littered with terrestrial

rocks. No attempt was made to search for
NUMBER 26 11

0 5 10

i i i km

N

Mai n

Nea r Wester n Icefiel d

••-..:•.•.•; ..'.l'%

Middl e Wester n Icefiel d

Battlement s Nunata k

7

Icefield ^

Pea k 233 0

Carapac e N unata k

FIGURE 4.—Meteorite collecting areas west of the Allan Hills. Dots outline bare icefields.

Stippled areas were searched by a reconnaissance mode. Striped areas were searched systematically during the 1981-1982 field season.

meteorites. Based on our observations at NVL

we predict that there is no concentration of

meteorites on this icefield. However, it should

certainly be searched at a future date to test

the predictive power of our NVL experience.

The Main Icefield, searched the longest and

most thoroughly, yielded 286 meteorites and

meteorite fragments during the 1981-1982

season, bringing the recovered total from this

field to 1020. There are at least two reasons

why the yield from this field remained high

this season despite five previous search efforts.

First these so-called "blue or bare ice" patches

are not really bare. At any given time there

will be a 30-50% snow cover largely in the

form of low, N-S trending linear drifts termed

sastrugi (Figure 6). As this snow cover shifts

from year to year, new, hitherto unobservable

ice surfaces, and the meteorites contained

thereon, become exposed. Second, and perhaps more importantly, for the first time systematic, steel-cleated snowmobile sweeps were
12 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

J

FIGURE 5.—Helicopter delivering snowmobiles to the Allan

Hills camp.

FIGURE 6.—Typical surface of the Main Icefield illustrating

partial snow cover.

FIGURE 7.—Snowmobile team preparing to spread out

abreast to a 30-50 meter spacing.

conducted over the areas of highest potential

(meteorites have been found over nearly the

entire Main Icefield but some areas show much

higher concentrations than others, nearly barren areas). Typically, once a promising area

was found, 4-5 snowmobiles (Figure 7) were

aligned abreast, 30-50 m apart, and a disciplined sweep was made in a chosen direction.

At the end of a sweep the line pivoted about

the "outside" searcher and reversed its direction. The "outside" searcher then became the

"inside" searcher following his/her track back

to its beginning while the others traversed new

ground. This sequence was repeated until the

area of interest was completely swept, with a

high probability of recovering almost all the

exposed meteorites. Meteorites as small as a

few millimeters in maximum dimension were

recovered by this technique.

Two and a half days were spent systematically searching the Near Western Icefield. Seventy-eight specimens representing a maximum

of 24 individuals were recovered. At least 52

weathered fragments appear to be from a single individual and are similar to 30 fragments

recovered in previous years from the same

area. This icefield yielded the largest meteorite

recovered in the 1981-1982 season: the 18 kg

hexahedrite described by Roy Clarke (p. 50).

A two-man, one-day reconnaissance at the

Middle Western Icefield returned 14 fragments representing 11 individuals. Several

other meteorites were found but not collected

because of poor weather and insufficient time.

These were flagged for collection next season.

From the short times spent at the Near and

Middle Western icefields it is clear that a large

number of meteorites remain on these surfaces

for future collecting. Under the reasonable

assumption that we are merely observing the

exposed portions of a single concentration system, there must be a very much larger number

of meteorites beneath the thin snow cover

separating the three icefields (Main, Near, and

Middle). Whether or not the meteorite concentration extends to the Far Western Icefields
NUMBER 26 13

should be known after the 1982-1983 season.

In summary, a total of 314 field sample

numbers were issued for the 378 meteorite

individuals and fragments recovered from the

Allan Hills icefields during the 1981-1982

season; the discrepancy between the two numbers reflects the obvious pairing of fragments

from the same meteorites.

Prior to the 1981-1982 season little effort

was made to accurately map the sites of meteorites found on the Allan Hills icefields. This

past season we surveyed the positions of the

recovered meteorites so that detailed location

maps could be produced. The 24 station triangulation network was used as a base for determining meteorite positions on the Main Icefield. The surveying instruments and techniques were rather crude but, we believe, more

than adequate for the possible uses of such

locality data. Where the triangulation network

was not a practical reference, an initial point

was established by a three-point resection from

prominent landmarks, plotted on the U.S.G.S.

Convoy Range 1:250,000 scale quadrangle map.

A detailed meteorite location map for the

Main Icefield has been produced and has already proven useful for examining the possibility of paired falls of similar meteorites (Marvin, personal communication).

Together with their terrestrial ages, a knowledge of the distribution of the larger meteorites on the icefields may help determine meteorite accumulation rates, ice dynamics, and

perhaps other factors bearing on meteorite

concentration mechanisms. The locations of

meteorites smaller than about 4 cm (maximum

dimension) in size are only useful for accurately locating the downwind edge of an icefield. The ever-present katabatic winds are

capable of skittering these small meteorites

across the ice until they lodge in the snow

bordering the bare ice areas.

As part of the on-going effort to delineate

the meteorite concentration mechanisms at the

Allan Hills, a large number of ice samples were

collected at regular intervals along two eastwest traverses across the Main Icefield, and the

sample positions flagged for future reference.

These ice samples were sent directly to Ohio

State University for petrographic examination

by Ian Whillans, a glaciologist with substantial

experience in Antarctica. Dr. Whillans spent

the final ten days with our party at the Allan

Hills and was most impressed with what he

tentatively concluded was an exposed vertical

ice section, now running horizontally eastwest, that could cover a 600,000 year period.

Two large blocks of ice were also collected for

radioactive dating and gas content determinations. One of these blocks was excavated from

directly beneath the find site of one of the

largest chondrites (18 cm, maximum dimension, field number 1556) that we had collected.

Finally, gravity measurements were made at

all 24 stations of the previously established

triangulation network across the Main Icefield

(Figures 8 and 9). Eight additional stations

were occupied on bedrock, from the northernmost tip of the Allan Hills south to Carapace

Nunatak, to help define any north-south regional gravity trend that might be present.

Calibration of the gravity data was provided

by a single, direct ice-thickness measurement

at station 3 of the network, obtained previously

by radio-echo sounding (Kovacs, 1980). With

this calibration the gravity values could be used

to compute ice thicknesses at all the other

stations and so model the shape of the ice/

bedrock interface beneath the station network.

A detailed description of this survey may be

found in the 1982 review issue of the Antarctic

Journal (vol. 16, no. 5). Only the conclusions

are summarized herein.

The calculated east-west profiles are shown

in Figure 10. The principal possible error

source in constructing these profiles is our

ignorance of the east-west regional gravity

trend, if any. However, the corrections for any

such trend would only rotate the entire profiles

up or down about the easternmost points without changing their relative shapes. Thus any

conclusions based on a comparison of relative

bedrock slopes will be valid irrespective of any

east-west correction.
14 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

SNOW COVERED

159° E

17 ^ \ 15 12

19

-76C45'S

KILOMETERS

ANTARCTIC METEORITE DISCOVERY AREA

FIGURE 8.—The triangulation network across the Main Icefield at Allan Hills.
NUMBER 26 15

FIGURE 9.—Gravity team at work.

A firm conclusion that can therefore be

reached is that, if the (exposed) Allan Hills act

as a barrier to ice movement, then surely the

barrier should begin much further west where

comparable bedrock slopes are present. This

conclusion is consistent with our 1982 reconnaisance of the Middle Western Icefield, which

revealed meteorite concentrations 35 km west

of the Allan Hills. It is, however, not consistent

with the latest reported triangulation network

remeasurements (Schultz and Annexstad, this

issue), which indicate a zero horizontal flow

rate, 5 km west of the Allan Hills, but an

eastward flow of ~ 1 meter/year for the ice 13

km west of the exposed barrier. Although we

have no certain explanation for the discrepancy between the two data sets, we do note

that the more precise instruments used in the

1981 resurvey lowered the maximum reported

horizontal flow rate from 2.5 to 1 meter/year.

At the same time, the earlier imprecision

causes the retention of high probable errors,

which remain on the order of the reported

5KM

- 1000

FIGURE 10.—Gravity-deduced bedrock configurations beneath the triangulation network.
16 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

rates themselves. The network was surveyed

again during the 1982-1983 season and it will

be interesting to see whether this data substantiates the latest reported (1981) rates.

Literature Cited

Cassidy, W.A., and J.O. Annexstad

1981. Antarctic Search for Meteorites, 1980-1981.

Antarctic Journal of the United States, 16(5):61-

62.

Kovacs, A.

1980. Radio-Echo Sounding in the Allan Hills, Antarctica, in Support of the Meteorite Field Program. Special Report 80-23, U.S. Army Corps of

Engineers, Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire.

Marvin, U.B.

1982. The Field Season in Victoria Land, 1978-

1979. In U.B. Marvin and B. Mason, editors.

Catalog of Meteorites from Victoria Land, Antarctica, 1978-1980. Smithsonian Contributions to

the Earth Sciences, 24:3-8
Ablation and Ice Movement at

the Allan Hills Main Icefield

between 1978 and 1981

Ludolf Schultz and John O. Annexstad

Introduction

The total number of meteorites found in

Antarctica through the southern summer of

1981-1982 exceeds 6000. More than 1000

meteorites have been collected on the icefields

near the Allan Hills in South Victoria Land.

The United States Antarctic Search for Meteorites (ANSMET), led by W.A. Cassidy, has

concentrated in this area not only to search for

meteorites but also to study the general phenomenon of meteorite concentrations on blue

icefields in the Antarctic. For a general introduction one is referred to Cassidy et al. (1977),

Marvin (1981), Schultz (1982), and Cassidy

and Rancitelli (1982).

Two factors contribute to the high meteorite

concentrations on the surface of some icefields.

(1) Small meteorites with weights of a few

grams can be detected on bare icefields while

in other areas of the Earth similar stones are

hidden among terrestrial rocks or vegetation.

(2) Weathering is less severe under Antarctic

conditions. Without liquid water meteorites

are preserved for longer periods of time than

in temperate climates. Furthermore, paired

meteorite falls contribute to the larger number

of meteorite finds. Detailed studies of all meLudolf Schultz, Max-Planck-Institut fur Chemie, D-65 Mainz,

West Germany. John O. Annexstad, NASA Johnson Space

Center, Houston, Texas, 77058.

teorite fragments are necessary to recombine

multiple falls. Seventy-five meteorites have

been tentatively identified as belonging to 13

individual falls in the Allan Hills region (Marvin and Mason, 1982). Even after taking into

account all of these effects, a mechanism that

concentrates meteorites fallen on large areas is

still necessary to explain the high concentrations on some icefields in Antarctica.

Several hypotheses have been proposed to

explain these meteorite concentrations (Cassidy et al., 1977; Nagata, 1978; Whillans,

1982). Generally, the process of meteorite concentration is based on the assumption that

meteorites entrapped in the ice in the interior

of the continent will emerge on the surface of

stagnant icefields close to coastal mountain

chains where the outward flow of ice is

blocked. All hypotheses need three basic parameters to obtain quantitative results: (1) terrestrial ages of meteorites; (2) ablation rates of

the ice in regions with high meteorite concentrations; and (3) direction and velocity of the

ice movement into these regions.

Terrestrial ages have been determined using

radioactive cosmogenic nuclides like

 14C, 26A1,

36C1, and 81Kr. The results show that a large

number of Antarctic meteorites have rather

high terrestrial ages with values up to 700,000

years (Fireman et al., 1979; Evans et al., 1982;

Nishiizumi et al., 1983; Freundel and Schultz,

in prep.).

17
18 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

To obtain information on ablation and ice

movement, a triangular network of 20 stations

was established at the Allan Hills icefield in

1978 (Nishio and Annexstad, 1979). Figure 11

shows a map of the Allan Hills area with the

triangulation chain, which is based in bedrock

and extends more than 13 km westward, crossing the icefield with high meteorite concentrations. Figure 12 shows the Allan Hills with

station 1 at the lower left corner and Figure

13 is a view from a helicopter in a southwesterly direction with the 1981 campsite. After

the first measurement in 1978, the chain was

resurveyed in 1979 (Nishio and Annexstad,

1980; Annexstad, 1982). We report here a

summary of another redetermination of the

properties of the network in November and

December 1981.

The method of the survey was essentially the

same as in previous years. However, the instruments used were more modern: a Wild theodolite with 400g

 (360°) reading was used for

the measurement of horizontal and vertical

angles, and the slope distances between adjacent stations were directly observed with a

Wild Distomat DI4L (Figure 14). Due to adverse weather conditions in November 1981,

in most cases only one side of each of the 18

(£) Station with NQ.

A Camp 1981

f l Blue Ice Field

•5.0 Ablation rate [cm/yr]

FIGURE 11.—Map of the Allan Hills Main Icefield with the triangulation network. Numbers

associated with the stations are measured ablation rates in cm/year. The insert shows calculated

elevations along the southern border of the network. The highest meteorite concentrations

have been found at the base of the slope that runs through the network between stations 8 and

13.
NUMBER 26 19

FIGURE 12.—View along the Allan Hills in a northerly

direction. The tripod (left lower corner) has been installed

over station 1 (Figure 11).

FIGURE 13.—Helicopter view in a southwesterly direction

of the Allan Hills icefield. Visible is the camp site (arrow)

and the "monocline" with a moraine, which supplies the

icefield with terrestrial rocks to confuse a meteorite hunter.

FIGURE 14.—After removal of the station pole, the survey

was carried out from instruments mounted over the hole in

the ice. A shelter protects the Wild T2 theodolite and the

Wild TI4L Distomat from vibrations due to the wind.

triangles (Figure 11) could be measured. The

observations from 1981, as well as those from

previous measurements, were used to calculate

the coordinates of each station relative to stations 1 and 2, which are positioned in the

bedrock of the Allan Hills. A standard program of triangulation networks, ARSM, at the

Fachhochschule Mainz was used for the data

reduction. The attempt to calculate vertical ice

movements was done with a computer program developed at the Max-Planck-Institiit in

Mainz. Ablation rates of the ice between two

measurements are given by the differences of

the height of each station pole from the surface

of the ice to the top.

Results and Discussion

ABLATION

The mean ablation rate observed for each

station over three years is given in Figure 11

(Annexstad and Schultz, 1983). The uncertainty

of these numbers is about 1 cm because the

ablation rate around the poles is not uniform.

Also from year to year the ablation rate may vary

due to different wind and temperature conditions. However, a mean ablation rate of about 5

cm/year is well established for the stations on ice

close to the areas with high meteorite concentrations. This observation is basic to all models for
20 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

the transport and concentration of meteorites.

Once buried in the ice, meteorites can emerge

to the surface and, assuming a horizontally stagnant icefield over a long period of time, build up

dense meteorite concentrations.

HORIZONTAL MOVEMENTS

Nishio and Annexstad (1980) reported horizontal ice velocities based on observations in

1978 and 1979. Their calculated values have

rather large uncertainties because only one year

of movement was measured. With the 1981 survey, changes over a three-year period could be

observed and, in addition, the use of the Distomat allowed a better determination of the network. For four selected stations the calculated

coordinates (in arbitrary units) of the measurements in 1978, 1979, and 1981 are shown in

Figure 15. This figure demonstrates that the

Allan Hills

HORIZONAL ICE

MOVEMENT

1978-1981

Stations! O Q

• '78

• '79

*"81

. 1m ,

t

FIGURE 15.—Calculated coordinates (in relative units) of

stations 4, 11, 16, and 20 for the measurements in 1978,

1979, and 1981. Due to the application of distance measurements in addition to the angle measurements the uncertainties could be reduced in the 1981 measurement.

[m]

C

0)

(Do

O

3

JS

a

0) 2

O

ALLAN HILLS

Ice Movement

between

1978 and 1981

3 5 7 9 11 13 15 17 19

Stations

FIGURE 16.—The calculated displacement in an easterly direction of all stations during the period 1978 to 1981.

observational uncertainties could be reduced for

the 1979 and 1981 measurements. The errors

of the horizontal velocities are based mainly on

the uncertainties of the initial measurement.

Figure 16 shows the horizontal displacement

of the stations relative to the 1978 measurement.

The error bars reflect the sum of the uncertainties of the 1978 and 1981 data. Three different

groups can be recognized according to their displacement in an eastward direction between

1978 and 1981. Stations 3 to 7 show, within the

limits of error, no movement in three years. This

area is the firn-covered icefield closest to the

Allan Hills. From stations 8 to 16 the horizontal

velocity of the ice increases from about 10±10

cm/year to about 100±70 cm/year. This is the

area with many meteorite finds. Stations 17 to

20 have the same rate of movement of about 1

m/year.

These measurements corroborate the suggestion that the ice moves into the Allan Hills region
NUMBER 26 21

from the west and becomes stagnant where many

meteorites are found. An additional resurvey of

the network in future years would enhance the

quality of the data, because the 1981 coordinates

with rather small errors could then serve as a

reference. However, to calculate the ice balance

in this region, measurements of the ice thickness

are needed.

VERTICAL MOVEMENTS

The determination of vertical angles in Antarctica is sometimes more difficult than the measurement of horizontal angles, because atmospheric effects can obscure the top of the poles

that are used as targets. Instrumental factors also

have more influence on vertical angle measurements. The vertical angles, therefore, have uncertainties that exceed the expected movement

of the ice. For example, for stations 9 to 13 the

mean error of the calculated elevations from the

vertical angle measurements are about 90, 40,

and 15 cm for the measurements of 1978, 1979,

and 1981, respectively. A resurvey of these parameters in a future field season could result in

better data.

Conclusions

The ablation rate of the ice at the Allan Hills

meteorite icefield averages about 5 cm/year.

The ice from the Eastern Antarctic ice sheet

approaching the Allan Hills slows down and becomes stagnant. The ice velocity 13 km west of

the Allan Hills is about 1 m/year; at a distance

of about 5 km from the Allan Hills it is almost

zero. The experimental uncertainties are too

high to determine vertical ice velocities; however, due to rather small errors of the 1981

measurement, a resurvey of the network could

result in useful values for this parameter.

Literature Cited

Annexstad, J.O.

1982. The Allan Hills Icefield and its Relationship to

Meteorite Concentration. In U.B. Marvin and

B. Mason, editors, Catalog of Meteorites from

Victoria Land, Antarctica, 1978-1980. Smithsonian Contributions to the Earth Sciences, 24:12-

18.

Annexstad, J.O., and L. Schultz

1983. Measurements of the Triangulation Network

at the Allan Hills Meteorite Icefield. In Proceedings of the Fourth International Symposium on Antarctic Earth Sciences, pages 617-619.

Cassidy, W.A., E. Olsen, and K. Yanai

1977. Antarctica: A Deep-Freeze Storehouse for Meteorites. Science, 198:727-731.

Cassidy, W.A., and L.A. Rancitelli

1982. Antarctic Meteorites.

70:156-164.

American Scientist,

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,

Catalog of Meteorites from Victoria Land, Antarctica, 1978-1980. Smithsonian Contributions to

the Earth Sciences, 24:70-74.

Fireman, E.L., L.A. Rancitelli, and T. Kirsten

1979. Terrestrial Ages of Four Allan Hills Meteorites: Consequences for Antarctic Ice. Science,

203:453-455.

Freundel, M., and L. Schultz

In prep. Terrestrial

 81Kr Ages of Antarctic Meteorites.

Marvin, U.B.

1981. The Search for Antarctic Meteorites. Sky and

Telescope, 1981:423-427.

Marvin, U.B., and B. Mason, editors

1982. Catalog of Meteorites from Victoria Land,

Antarctica, 1978-1980. Smithsonian Contributions to the Earth Sciences, 24: 97 pages.

Nagata, T.

1978. A Possible Mechanism of Concentration of

Meteorites within the Meteorite Ice Field in

Antarctica. Memoirs of the National Institute of

Polar Research (Japan), special issue, 8:70-92.

Nishiizumi, K., J.R. Arnold, D. Elmore, X. Ma, D.

Newman, and H.E. Gove

1983.

 36C1 and 53Mn in Antarctic Meteorites and

10Be-36Cl Dating of Antarctic Ice. Earth and

Planetary Science Letters, 62:407-417.

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.
22 NUMBER 26

1980. Studies on the Ice Flow in the Bare Ice Area Whillans, I.M.

near the Allan Hills in Victoria Land, Antarc- 1982. Meteorite Concentration Mechanism near the

tica. Memoirs of the National Institute of Polar Allan Hills and the Age of the Ice. In C. Bull

Research (Japan), special issue, 17:1-13. and M.E. Lipschutz, editors, Workshop on AntSchultz, L. arctic Glaciology and Meteorites. Lunar and

1982. Antarctische Meteorite. Die Naturwissenschaf- Planetary Institute Technical Report, 82-03:35.

ten, 69:220-225. Houston: Lunar and Planetary Institute.
Descriptions of Stony Meteorites

Roberta Score, Carol M. Schwarz, and Brian Mason

This section provides descriptions of the individual specimens, arranged by class. Within the

chondrites, the specimens are grouped according

to the Van Schmus-Wood (1967) classification,

and the descriptions follow the order of increasing petrographic type. The descriptions are

based largely on those published in the Antarctic

Meteorite Newsletter, with additional information

as available. The letter-number designation concurs with guidelines recommended by the Committee on Nomenclature of the Meteoritical Society; it carries the following information: ALH

(Allan Hills); A80 (Expedition A, 1980); xxx

(digits indicating the number of the specimen).

The original weight of the specimen is given to

the nearest gram (nearest 0.1 gram for specimens

weighing less than 100 grams).

This section comprises material on all characterized meteorites collected during the 1980-

1981 and 1981-1982 field seasons. Specimens

weighing less than 100 grams are listed without

descriptions, unless they show distinctive features. A summary account of the petrography of

the 1980-1981 collections has been published

by Mason and Clarke (1982).

Roberta Score and Carol M. Schicarz, Northrop-Houston, Johnson

Space Center, Houston, Texas, 77058. Brian Mason, Department

of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560.

Chondrites

CLASS C2

FIGURES 17, 18

ALHA81002 (14.0 g).—This is a friable jet

black stone (2.5 X 2.5 X 2.5 cm) of pyramidal

form, without fusion crust. Chondrules and inclusions can be distinguished on the surface; a

minute amount of salt deposit was present on

one surface.

ALHA81004 (4.7 g).—Dull black fusion crust,

blistery along one edge, covers most of this stone

(3 X 1.5 X 1 cm). Small white irregular and

rounded inclusions are apparent in the black

matrix; several small oxidation halos were noted.

Thin sections of these specimens are very similar to each other and to those of ALHA77306

and 78261, the previously described C2 chondrites from the Allan Hills; these four meteorites

may be paired. The sections show numerous

small colorless grains (up to 0.1 mm) and irregular aggregates (up to 0.6 mm) mainly of olivine,

and a few small chondrules (up to 0.6 mm) in an

opaque to translucent brown isotropic matrix.

Trace amounts of nickel-iron and troilite are

present as widely dispersed minute grains. Microprobe analyses of the olivine show a composition

range of Fao to Fa52, mean Fan, with a strong

peak at Fa0 to Fai characteristic for chondrule
24 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 18.—ALHA81004, C2 chondrite. Photomicrograph of thin section (area of field is 3 X 2 mm), irregular

grains and rare chondrules, mainly of olivine (white to gray)

in translucent to opaque matrix (black).

FIGURE 17.—C2 chondrites. Note blistery fusion crust

around edge of ALHA81004.

olivine (isolated olivine grains show a wide composition range). A few grains of clinoenstatite

and one grain of diopside were analyzed.

FIGURE 19.—ALHA81003, C3 chondrite. Note pitted surface, and white inclusions in black matrix.

CLASS C3

FIGURES 19, 20

ALHA81003(10.1 g).—This stone (2.5X2.0

X 1.5 cm) from the Allan Hills has only one small

area of fusion crust. The exposed surfaces are

black and are dotted with abundant irregular

white inclusions, some of which are rusty. Sparse

metal grains are scattered through the matrix.

The section shows numerous chondrules up to
NUMBER 26 25

FIGURE 20.—ALHA81003, C3 chondrite. Photomicrograph of thin section (area of field is 3 X 2 mm); note large

olivine-rich chondrules in brown to black semi-opaque matrix.

3 mm across and irregular crystalline aggregates

up to 2 mm in maximum dimension, set in a

minor amount of dark brown to black semiopaque matrix. The chondrules and aggregates

consist mainly of olivine with some polysynthetically twinned pyroxene. Trace amounts of nickeliron are present as minute grains. Sulfide is present in minor amount, finely dispersed throughout the section. Microprobe analyses of chondrule olivine show a wide compositional range:

Fa0 to Fa40, mean Fa8; the matrix consists largely

of fine-grained iron-rich olivine, Fa40 to Fa60.

Pyroxene in the chondrules is clinoenstatite,

mostly near Fsi, but with occasional Fe-rich

grains. The meteorite is a C3V chondrite; previously described C3 chondrites from the Allan

Hills are C3O (Scott et al., 1981).

RKPA80241 (0.6 g).—This small specimen

(1.5 X 0.5 X 0.5 cm) from Reckling Peak has a

little fusion crust. The thin section shows a closepacked aggregate of chondrules (up to 2.5 mm

across) and irregular granular aggregates, set in

a small amount of black (probably carbonaceous)

matrix. A minor amount of nickel-iron is present,

in several forms: as small grains dispersed

through some chondrules, concentrated around

the margins of some chondrules, and as rare

globules up to 0.8 mm across in the matrix. The

silicate material consists largely of olivine and

polysynthetically twinned clinopyroxene. Wellpreserved fusion crust, up to 1.2 mm thick, rims

part of the section. Weathering is extensive, with

brown limonitic staining pervasive throughout

the section. Microprobe analyses show olivine

and pyroxene with variable composition; for 30

olivine analyses the Fa range is 0.7-5.5 (except

for one of Fa36), and the mean is Fa3; for 15

pyroxene analyses the range is Wo 0.3-1.5, En

90-98, Fs 1-8, with mean of Wo0.7En95Fs4. The

meteorite is tentatively classified as a C3V chondrite.

CLASS H3

FIGURES 21, 22

OTTA80301 (35.5 g).—This rounded stone

(3.5x3x 2 cm) from Outpost Nunatak is almost

competely covered with brown to black fusion

crust, pitted in places. A broken corner reveals

abundant chondrules and irregular inclusions.

The thin section shows a close-packed aggregate

of chondrules and some irregular granular enclaves; the matrix consists of fine-grained silicates

with a moderate amount of nickel-iron and a

lesser amount of troilite. Chondrules range up

FIGURE 21.—OTTA80301, H3 chondrite, a rounded stone

almost completely covered with brown to black fusion crust.
26 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 22.—Photomicrographs of thin sections of H3 chondrites (area of each field is 3 X 2

mm): a, RKPA80205; b, OTTA80301. (Closely packed aggregates of chondrules, irregular

enclaves, and mineral grains set in a minor amount of dark matrix.)

to 1.1 mm across, and show a close-packed aggregate of chondrules and some irregular granular enclaves; the matrix consists of fine-grained

silicates with a moderate amount of nickel-iron

and a lesser amount of troilite. Chondrules range

up to 1.1 mm across, and show a variety of types,

the commonest being granular olivine and olivine-pyroxene (polysynthetically twinned clinobronzite), porphyritic olivine, and fine-grained

pyroxene. Some intergranular glass in the chondrules is clear and transparent, but much of it is

turbid and partly devitrified. Minor brown limonitic staining is present around nickel-iron

grains. Microprobe analyses show olivine and

pyroxene with variable composition: olivine, Fan

to Fa 19, average Fai8; pyroxene, Fs4 to Fsn, average Fsio.

RKPA80205 (53.8 g).—This stone (4 X 3 X

2.5 cm) is partly covered by dull brownish black

fusion crust; a weathering rind, 1 mm thick, is

present, but the interior is only moderately

weathered. The thin section shows a closely

packed mass of chondrules (0.2-2.4 mm diameter), chondrule fragments, and irregular crystalline aggregates, with interstitial nickel-iron and

troilite and a small amount of dark fine-grained

matrix. A considerable variety of chondrules is

present; many are granular to porphyritic olivine

with transparent to turbid intergranular glass;

others consist of granular polysynthetically

twinned clinopyroxene with or without olivine,

fine-grained pyroxene, or barred olivine. Minor

brown limonitic staining is present throughout

the section. Microprobe analyses show olivine

ranging in composition from Fa 17 to Fa2o, with a

mean of Fai8; the pyroxene is low-calcium (CaO

0.1-0.2%) clinobronzite, ranging in composition

from Fs5 to FS13, with a mean of Fsi8.

RKPA80207 (17.7 g).—Dull black fusion

crust covers one surface of this specimen (3 X

2.5 X 1.5 cm); other surfaces are deeply weathered. In thin section, chondrules are abundant,

ranging from 0.3 to 1.5 mm in diameter; a wide

variety is present, the commonest being granular

olivine and olivine-pyroxene, and fine-grained

pyroxene. The granular chondrules have intergranular glass, sometimes pale brown and transparent but commonly turbid and partly devitrified. Irregular granular clasts and chondrule

fragments are also present. Most of the pyroxene

is polysynthetically twinned. The matrix consists

of fine-grained olivine and pyroxene, with minor

subequal amounts of nickel-iron and troilite.

Veinlets of limonite and brown limonitic staining
NUMBER 26 27

pervade the section. Microprobe analyses show

olivine ranging in composition from Fa 15 to Fa29,

with a mean of Fa2o (% mean deviation of FeO is

32). Pyroxene composition range from Fs0 to

Fs28, with a mean of Fsi3. [This meteorite is

reclassified H3 from L3 by Scott (p. 76)].

CLASS L3

FIGURES 23, 24, 25, 26, 27

ALHA80133 (3.6 g).—This small stone (2.5

X 1.5 X 1 cm) has no fusion crust but has a

reddish brown weathered surface showing

rounded inclusions. The thin section shows a

close-packed mass of chondrules and chondrule

fragments with a small amount of dark finegrained matrix. Chondrules range from 0.3 to

1.5 mm in diameter and show a diversity of type,

the commonest being granular olivine and olivine-pyroxene, barred olivine, and fine-grained

pyroxene. Transparent pale brown glass is present in some of the granular chondrules. Much of

the pyroxene is polysynthetically twinned clinobronzite. Weathering is extensive, with brown

limonitic staining throughout the section. Microprobe analyses show that olivine and pyroxene

have highly variable composition: olivine, Fao.5

FIGURE 23.—ALHA81024, L3 chondrite, a rounded angular stone with several deep fractures, with a reddish brown

weathered surface.

FIGURE 24.—RKPA80256, L3 chondrite, a fractured stone

partly covered with brownish black fusion crust; the fracture

surface shows a closely packed aggregate of chondrules and

enclaves in dark fine-grained matrix.

to Fa35, mean Fai4; pyroxene, Fs5 to Fs3o, mean

Fsi4. This specimen was originally classified as a

C3 chondrite, but Dr. E.R.D. Scott (personal

communication) has identified it as an L3 chondrite, paired with ALHA77011 and many other

L3 chondrites from the Allan Hills.

ALHA81024 (797 g).—This angular specimen (10 X 8 X 6.5 cm) is covered with reddish

brown to black fusion crust on all sides except

where eroded away, mainly along fractures. The

interior is reddish brown and appears to be extremely weathered. The thin section shows a

close-packed aggregate of chondrules, up to 1.5

mm across; a variety of types is present, including

porphyritic olivine, barred olivine, granular olivine and olivine-pyroxene, and fine-grained pyroxene. Much of the pyroxene is polysynthetically twinned clinobronzite. Some intergranular

glass within the chondrules is pale brown and

transparent, but commonly is turbid and partly

devitrified. Minor amounts of nickel-iron (largely

altered to brown limonite) and troilite are present in the matrix. Olivine and pyroxene have

variable composition. Olivine composition

ranges from Fa3 to Fa28, with a mean of Fai9 (%

mean deviation FeO is 34). Pyroxene composition ranges from Fs2 to FS24, with a mean of Fsi0

(% mean deviation FeO is 79). Transparent chondrule glass has the following mean composition

(weight percent): SiO2 63.3, A12O3 22.5, FeO

0.9, MgO 0.2, CaO 0.2, K2O 3.3, Na2O, 8.8,
28 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 25.—Photomicrographs of thin sections of L3 chondrites (area of each field is 3 X 2 mm): a, ALHA80133; b,

ALHA81024; c, RKPA80256. (Closely packed aggregates

of chondrules, irregular enclaves, and mineral grains set in

a minor amount of dark matrix).

FIGURE 26.—ALHA81031, L3 chondrite, a fractured and

weathered stone showing some light-colored angular clasts

on the surface.

TiO2 0.8, MnO 0.03; this composition is close to

anorthoclase.

ALHA81025 (379 g).—This stone (9.5 X 8 X

4.5 cm) is extremely weathered; rounded and'

irregular inclusions (one 7x 5 mm) are visible

on the weathered surfaces.

ALHA81030 (1851 g).—Patchy black fusion

crust is present on all surfaces of this angular

stone (18 X 9 X 7.5 cm). Several large fractures

penetrate the interior. Inclusions can be seen on

the exterior and on chipped surfaces.

ALHA81031 (1594 g).—This is an angular

specimen (73 X 9 X 9 cm) with small areas of

thin lustrous black fusion crust. The surface is

weathered dark reddish brown and is penetrated

by numerous fractures.
NUMBER 26 29

FIGURE 27.—ALHA81031, L3 chondrite, an angular weathered stone partly covered with lustrous black fusion crust;

photographed as found.

ALHA81032 (726 g).—Lustrous black fusion

crust is present on small areas of this angular

stone (9x9x 6 cm). Light colored clasts or

chondrules up to 0.5 cm across are visible on

weathered surfaces.

The thin section of ALHA81025 shows a

close-packed aggregate of chondrules and chondrule fragments up to 3.5 mm across, in a finegrained matrix of olivine, pyroxene, troilite, and

a little nickel-iron. Chondrule types include porphyritic olivine, granular olivine and olivine-pyroxene, barred olivine, and radiating pyroxene.

Much of the pyroxene is polysynthetically

twinned clinobronzite. Intergranular glass is

present in the chondrules, usually turbid but

sometimes transparent and purple-brown.

Weathering is extensive, with small areas of

brown limonite throughout the section. Microprobe analyses show that olivine and pyroxene

have variable composition. Olivine composition

ranges from Fai to Fa4i, with a mean of Fai8

(percent mean deviation FeO is 76). Pyroxene

composition ranges from Fs3 to Fs40, with a mean

of Fsi5 (percent mean deviation FeO is 75). Purple glass in a chondrule has the following mean

composition (weight percent): SiO2 56.8, A12O3

24.1, FeO 3.7, MgO 2.4, CaO 0.4, K2O 4.1,

Na2O 8.8, TiO2 1.2, MnO 0.09.

Thin sections of ALHA81025,81030,81031,

and 81032 are so similar in texture, range of

mineral composition, and degree of weathering

that these meterorites can be paired, together

with ALHA77011 (Scott, personal communication).

RKPA80256 (153 g).—This meteorite (7 X

5.5x 3 cm) is almost totally covered with brownish black fusion crust. Chondrules and white and

gray clasts up to 5 mm across are visible on

exposed surfaces. The thin section shows a

closely packed mass of chondrules (0.3-1.8 mm

diameter) and irregular crystalline aggregates.

Some of the chondrules have prominent dark

rims. The sparse matrix is dark and fine-grained,

with a small amount of coarser nickel-iron and

troilite scattered throughout. A notable variety

of chondrules is present; many are granular or

porphyritic olivine and olivine-pyroxene with

transparent to turbid interstitial glass. The pyroxene is polysynthetically twinned clinobronzite. There is a little limonitic staining in association with metal grains. Microprobe analyses

show olivine ranging in composition from Fa2o

to Fa25, with a mean of Fa22 (% mean deviation

of FeO is 8.3). The pyroxene is low-calcium (CaO

= 0.1-0.8%), with a composition range of Fsio

to Fs26 and a mean of Fsi8.

CLASS LL3

FIGURE 28

ALHA81251 (158 g).—This meteorite (6.5 X

6 X 2.5 cm) is partly covered with thin lustrous

black fusion crust. Broken surfaces show abundant chondrules up to 5 mm in diameter. The

interior is weathered a deep reddish brown color.

The thin section of ALHA81251 shows a

close-packed aggregate of chondrules and chon-
30 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 28.—Photomicrograph of a thin section of

ALHA81251, an LL3 chondrite (area of the field is 3 X 2

mm). Numerous chondrules, with some angular enclaves

and mineral grains, set in a minor amount of dark matrix.

drule fragments, up to 3 mm in maximum dimension. Most of the matrix is black and opaque,

with small grains of olivine and pyroxene; the

black matrix appears to be carbonaceous, with

small amounts of troilite and nickel-iron (largely

weathered to limonite). A wide variety of chondrule types is present, including barred olivine,

granular olivine and olivine-pyroxene, and finegrained pyroxene. Clear glass is present in barred

olivine chondrules. Microprobe analyses show

olivine and pyroxene with variable compositions:

olivine, Fai to Fa29, mean Fa14 (percent mean

deviation FeO is 64); pyroxene, Fs2 to Fs28, mean

Fsi3 (percent mean deviation FeO is 72). Clear

glass in a barred olivine chondrule has the following composition (weight percent): SiO2 61.4,

A12O3 23.5, FeO 1.7, MgO 2.0, CaO 0.4, Na2O

4.8, K2O 1.6, TiO2 1.1, MnO 0.01.

ALHA81251 is tentatively paired with

ALHA76004 (Scott, personal communication).

CLASS H4

FIGURES 29, 30

Four H4 chondrites (ALHA80106, 432 g;

80121, 39.1 g; 80128, 138 g; 80131, 19.8 g)

were collected at the Allan Hills in 1980-1981,

and three (ALHA81022, 912 g; 81044, 386 g;

81048, 190 g) have been identified in the 1981-

1982 collection. Three small specimens were

collected near Reckling Peak in 1980-1981:

RKPA80232, 80.1 g; 80237, 22.2 g; 80267,

24.2 g.

ALHA80106 consists of five fragments, four

of which can be fitted together. Areas of shiny

black fusion crust are present, but areas devoid

of fusion crust are weathered reddish brown, and

weathering appears pervasive throughout the

fragments. ALHA80128 has dull black fusion

crust on all but one surface; several large fractures penetrate the specimen, and the interior is

medium gray speckled with white and dark gray

inclusions. ALHA81022 has thin black fusion

crust over much of the surface; where the interior is exposed many chondrules are visible.

ALHA81044 and 81048 are severly weathered

and fractured specimens with little or no fusion

crust.

In thin sections these specimens show the typical features of Class H4 chondrites: well-developed chondrules, the commonest being granular

and porphyritic olivine and olivine-pyroxene,

barred olivine, and fine-grained radiating pyroxene (much of the pyroxene is polysynthetically

twinned clinobronzite); the groundmass consists

FIGURE 29.—ALHA81022, H4 chondrite, a fractured stone

with thin black fusion crust on the original surface; numerous mm-sized chondrules are visible on the fracture surface.
NUMBER 26 31

FIGURE 30.—Photomicrographs of thin sections of H4 chondrites (area of each field is 3 X 2

mm): a, RKPA80237; b, ALHA81044. (Numerous well-defined chondrules are present, but

some chondrule margins tend to merge with the granular matrix).

of fine-grained olivine and pyroxene, with minor

amounts of nickel-iron and troilite. The Allan

Hills specimens have olivine of essentially uniform composition (Fai8 to Fai9) and somewhat

variable pyroxene (Fsi5 to FS22). The

ALHA80xxx specimens are possibly paired;

ALHA81044 and 81048 are probably pieces of

a single meteorite; and ALHA81022 is tentatively paired with ALHA78084 and 77009. The

Reckling Peak specimens have olivine (Fai8 to

Fa 19) and pyroxene (Fsi6) of essentially uniform

composition and are possibly paired.

CLASS L4

FIGURES 31, 32

Two L4 chondrites (RKPA80216, 44.3 g;

80242, 7.3 g) were collected near Reckling Peak

in the 1980-1981 season, and one

(ALHA81040, 194 g) has been identified in the

1981-1982 collection from the Allan Hills.

ALHA81040 is a round stone (5.5 X 5 X 5 cm)

with about 75% of its surface covered with dull

black fusion crust; where fusion crust is lacking

the surface is weathered to a deep reddish brown.

The Reckling Peak specimens are small weathered stones completely or almost completely covered with fusion crust.

FIGURE 31.—ALHA81040, L4 chondrite, a rounded stone

with much of the surface covered with dull black fusion

crust.

Thin sections of these meteorites show the

typical features of L4 chondrites. Chondritic

structure is well developed, with a variety of

chondrule types; irregular granular aggregates,

possibly chondrule fragments, are also present.

The chondrules are set in a fine-grained matrix

consisting largely of olivine and pyroxene, with

minor subequal amounts of nickel-iron and troilite. Some of the pyroxene, especially in the chondrules, is polysynthetically twinned clinobron-
32 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

.>

FIGURE 32.—Photomicrographs of thin sections of L4 chondrites (area of each field is 3 X 2

mm): a, RKPA80216; b, ALHA81040. (Chondritic structure is prominent, but some chondrules

show partial integration with the granular matrix; note barred chondrule within barred

chondrule in RKPA80216).

zite. Olivine and pyroxene are essentially uniform in composition: olivine, Fa23 to Fa25; pyroxene, Fsi9 to Fs2i. The Reckling Peak specimens

resemble each other closely in mineralogical

compositions, texture, and degree of weathering,

and are possibly paired.

CLASS H5

FIGURES 33, 34

Six H5 chondrites were collected at the Allan

Hills in the 1980-1981 season, but only one

(ALHA80132, 152 g) weighs more than 100 g.

ALHA80132 (8 X 4.5 X 3 cm) is a flat stone

largely covered with dull brownish black fusion

crust with prominent flow bands on one surface:

it is considerably fractured and has a thick weathering rind. Nine have been identified in the

1981-1982 collection, all weighing more than

100 g. Nineteen were collected near Reckling

Peak in 1980-1981, but most were small specimens; the only ones larger than 100 g are

RKPA80220 (124 g) and 80233 (413 g).

RKPA80220 is a complete stone (5.4 X 4 X 3

cm) entirely covered with thin patchy fusion

crust; several fractures penetrate the interior,

which is considerably weathered. RKPA80233

FIGURE 33.—ALHA81015,an H5 chondrite, photographed

as found.

(8.5 X 6.5 X 5 cm) has one planar fracture

surface, and the rest of the surface is covered

with patches of fusion crust; the fracture surface

contains numerous chondrules, which can

easily be plucked out. Most of the 1981-1982

H5 chondrites from Allan Hills (ALHA81015,

81019, 81020, 81033, 81034, 81036, 81039,
NUMBER 26 33

FIGURE 34.—ALHA81033, H5 chondrite, photomicrograph of thin section (area of field is 3 X 2 mm); chondritic

structure is well developed, but margins of chondrules tend

to merge with the granular groundmass.

81042, 81067) are individual stones partly covered with fusion crust. ALHA81033 consists of

six weathered fragments. ALHA81039 (10 X 4.5

X 4 cm) consists of two pieces, which fit together,

and a small additional piece; black fusion crust is

present on most of the original surface, and a

weathering rind is present on fracture surfaces,

but the interior is light gray and only slightly

weathered. ALHA81067 (7 X 5.5 X 4 cm) was

collected as two pieces, which fit together perfectly but do not form a complete stone; some

patchy fusion crust is present on original surfaces, and fracture surfaces are deeply weathered

to an iridescent red-brown color.

In thin sections all the H5 chondrites show a

generally well-developed chondritic structure

with a variety of chondrule types, including granular and porphyritic olivine and olivine-pyroxene, barred olivine, and fine-grained pyroxene.

Chondrule margins may be somewhat diffuse,

tending to merge with the granular groundmass,

which consists largely of olivine and pyroxene,

with minor amounts of nickel-iron and troilite;

minute grains of sodic plagioclase can sometimes

be detected. The compositions of the olivine

(Fai6 to Fa i9) and orthopyroxene (Fsi4 to Fsi7)

are uniform within the individual specimens.

The Reckling Peak H5 chondrites resemble

each other in texture, mineral compositions, and

degree of weathering; RKPA80220 and 80223

have been tentatively paired, as have RKPA

80250 and 80251, and further research will

probably extend these pairings. The Allan Hills

1980-1981 H5 chondrites, except ALHA

80123, are also very similar in texture, mineral

compositions, and degree of weathering, and are

tentatively paired; ALHA80123 is more severely

weathered and may be a different fall. Possible

pairings among the Allan Hills 1981-1982 H5

chondrites remain to be studied.

CLASS L5

FIGURES 35, 36, 37

Three small L5 chondrites were collected near

Reckling Peak in the 1980-1981 season: RKPA

80209 (9.7 g), 80228 (11.1 g), 80268 (3.4 g);

they are individual stones partly or completely

covered with fusion crust. Three L5 chondrites

have been identified in the 1981-1982 Allan

Hills collection: ALHA81017 (1434 g), 81018

(2236 g), 81023 (418 g). ALHA81017 consists

of two pieces (13.5 X 8 X 7 cm and 10 X 9 X 5.5

cm), which do not fit together but are clearly

parts of a single stone. Each piece has small areas

of dark fusion crust and are somewhat weathFIGURE35.—ALHA81018, L5 chondrite, an angular

weathered stone partly covered with dull black fusion crust.
34 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 36.—ALHA81023, L5 chondrite, found as fragments with remnants of black fusion crust.

FIGURE 37.—Photomicrographs of thin sections of L5 chondrites (area of fields is 3 X 2 mm):

a, RKPA80209; b, ALHA81023. (Chondrules are prominent, but show some integration with

the granular groundmass; note well-preserved fusion crust on RKPA80209).

ered, with oxidation halos around metal grains.

ALHA81018 is an angular stone (13.5 X 11 X

10 cm) partly covered with dull black fusion

crust; several fractures penetrate the stone, and

a weathering rind approximately 10 mm thick is

present. ALHA81023 was found as two large

pieces, two small pieces, and many tiny chips;

none of the pieces fit together, but they are
NUMBER 26 35

clearly related. Remnants of fusion crust are

present. The interior is light gray and shows

many dark colored chondrules and irregular inclusions.

In thin sections the L5 chondrites show a generally well-developed chondritic structure, with

a variety of chondrule types, including porphyritic olivine, granular olivine and olivine-pyroxene, and radiating fine-grained pyroxene. Chondrule margins are often diffuse, tending to merge

with the granular groundmass, which consists

largely of olivine and pyroxene with minor subequal amounts of nickel-iron and troilite. The

compositions of the olivine (Fa23 to Fa25) and

orthopyroxene (Fs]9 to Fs2i) are essentially uniform within the individual specimens.

ALHA81017, 81018, and 81023 are very similar in all respects, and the possibility of their

being paired should be considered.

CLASS LL5

FIGURE 38

Two LL5 chondrites were collected near Reckling Peak during the 1980-1981 field season

RKPA80234 (136 g) and RKPA80253 (4.6 g).

Although they show some similarities, there are

sufficient differences to indicate that they are

probably not paired: 80253 is practically unweathered, whereas 80234 is considerably weathered, with extensive brown limonitic staining.

RKPA80234 is a flat stone, 6 X 5 X 2 cm, with

fusion crust on one surface; the other surfaces

have weathered to a reddish brown color. In thin

sections chondritic structure is barely discernible,

the sparse chondrules being largely obscured by

extensive brecciation. The section shows an aggregate of olivine and pyroxene, with a little

troilite and nickel-iron. Microprobe analyses

gave the following compositions: olivine, Fa26;

orthopyroxene, Fs22.

RKPA80253 is a small flat stone, 2X2X 1

cm, almost totally covered with black fusion

crust, blistery in places; the interior has a whitish

gray color and contains many dark angular inclusions. In thin section chondrules are fairly abundant, and are relatively large, ranging up to 3

mm in diameter. Brecciation is prominent, and

many of the chondrules are fractured and deformed. Only a little nickel-iron is present. Microprobe analyses gave the following compositions: olivine, Fa27; orthopyroxene, Fs22 with a

few more Mg-rich grains; plagioclase, Ani0. This

FIGURE 38.—Photomicrographs of thin sections of LL5 chondrites (area of fields is 3 X 2 mm):

a, RKPA80234; b, RKPA80253. (Chondritic structure is somewhat obscured by the extensive

brecciation these meteorites have experienced).
36 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

meteorite is classified as an LL5 chondrite, but

different areas of the brecciated structure show

features of higher and lower type.

CLASS E5

FIGURE 39

RKPA80259 (20.2 g).—Thin iridescent fusion

crust covers most of this small stone (2.5 X 1.5

X 1.5 cm). The interior is dark colored and

weathered, and shows a small amount of a white

evaporite deposit. In thin section chondrules are

rare and barely discernible, the meteorite consisting largely of fine-grained enstatite (mean

grain size approximately 0.05 mm), with some

nickel-iron and troilite. Weathering is very extensive, with much red-brown limonite throughout the section. The silicate material is blackened

by the presence of finely dispersed troilite, probably the result of an episode of severe shock.

Microprobe analyses showed that the enstatite is

almost pure MgSiOg, with minor amounts of

A12O3 (0.1-0.3%), FeO (0.1-0.5%), and CaO

(0.5-0.8%.).

CLASS H6

FIGURES 40, 41

Four H6 chondrites were collected at the Allan

Hills in the 1980-1981 season: ALHA80118,

80122, 80126, 80130. Each weighs less than 100

g; 81022, 80126, 80130 are very similar and are

probably pieces of a single meteorite, but 80118

is less weathered and is probably a different fall.

Six H6 chondrites have been identified in the

1981-1982 collection: ALHA81035 (256 g),

81037 (320 g), 81038 (229 g), 81093 (271 g),

81102 (196 g), 81111 (210 g). ALHA81035 is a

complete stone, 7.5 X 5.5 X 3 cm, entirely covered with patchy fusion crust; it is extensively

weathered. ALHA81037 is an angular specimen,

7.5 X 6 X 4 cm, with fusion crust on all but two

sides; it is polygonally fractured, and the interior

shows moderate weathering with rusty halos

around metal grains. ALHA81038 is a rounded

oblong stone, 7x4x 4 cm, with remnants of

fusion crust; several fractures penetrate the interior, which is extensively weathered. ALHA

81093 is an equidimensional stone, 6 X 5.5 X 4

cm, completely covered with dull black fusion

crust. ALHA81102 is a weathered stone, 7.5 X

FIGURE 39.—RKPA80259, E5 chondrite, photomicrograph

of thin section (area of field is 3 X 2 mm); an enstatite

chondrule (center) in a matrix consisting largely of enstatite

grains (white) with nickel-iron and sulfide (black).

FIGURE 40.—ALHA81035, H6 chondrite, photomicrograph of thin section (area of field is 3 X 2 mm); chondritic

structure is barely discernible, the chondrules merging with

the granular groundmass.
NUMBER 26 37

FIGURE 41.—H6 chondrites.

5 x 3 cm, with thin remnant fusion crust; most

of the surface is oxidized to a dark red-brown

color. ALHA81111 is a rounded stone, 8 X 6 X

4 cm; the upper half is covered with frothy black

fusion crust, the lower half is weathered to an

iridescent brown color.

Nineteen H6 chondrites were collected near

Reckling Peak in the 1980-1981 season; they all

weigh less than 100 g except RKPA80201 (813

g) and 80231 (238 g). RKPA80201 is a rectangular stone, 12 X 6 X 5.5 cm, almost completely

covered with black fusion crust showing polygonal fractures; minute amounts of white evaporite

deposits are present in some of the fractures.

RKPA80231 is a weathered and fractured stone,

7x5x 3 cm, with remnants of dull black fusion

crust. All the Reckling Peak specimens except

RKPA80201 are paired because of their similar

and characteristic texture. Specifically they appear to have been considerably fractured and the

minerals partly granulated; this feature has been

made more prominent by extensive weathering,

which has developed numerous thin limonite

veinlets throughout the specimens.

All the H6 chondrites show very similar petrographic features. Chondrules are sparse and

poorly defined, tending to merge with the granular groundmass, which consists mainly of olivine

and pyroxene, with minor amounts of nickeliron, troilite, and sodic plagioclase. Compositions
38 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

of the olivine (Fan to Fa2o) orthopyroxene (Fsi5

to Fsi7), and plagioclase (Ani2 to Ani3) are uniform within the individual specimens.

CLASS L6

FIGURES 42, 43

Fifteen L6 chondrites were collected at the

Allan Hills in the 1980-1981 season, 12 weighing more than 100 g each. Macroscopic examination indicated that they might be paired as

pieces of a single meteorite, and this has been

supported by evidence from thin sections, which

shows that they are identical in texture, mineral

compositions, and degree of weathering. Three

L6 chondrites have been identified in the 1981 —

1982 Allan Hills collection: ALHA81016 (3850

g), 81026 (515 g), 81027 (3835 g). ALHA81016

is a rounded stone, 15X12X1 1 cm, with

remnants of fusion crust; most of the surface is

smooth and weathered to a dark reddish brown

color; the interior is a lighter brown-green color.

Mineral grains with cleavage faces and distinct

chondrules up to 4 mm across are visible on both

FIGURE 42.—ALHA81016, an L6 chondrite, photographed

as found.

FIGURE 43.—Photomicrographs of thin sections of L6 chondrites (area of each field is 3 X 2

mm): a, RKPA80202, b, RKPA80252. (Chondritic structure is barely discernible, the chondrules merging with the granular groundmass; the dark glassy veinlet in RKPA80202 contains

clear isotropic material tentatively identified as ringwoodite and majorite).
NUMBER 26 39

exterior and interior surfaces. ALHA81026 is a

knobby stone, 11 X 6 X 5.5 cm, partly covered

with dull black fusion crust; the interior is pale

gray, with brown limonitic halos around metal

grains. ALHA80127 consists of two pieces that

fit together as an incomplete rounded stone, 17

X 11.5 X 10 cm; patchy fusion crust covers much

of the surface, and the interior is extensively

weathered. This meteorite has been shocked and

plagioclase converted to maskelynite, with CaO

content equivalent to Ani0 but with Na2O low

and variable, 4.0-5.2%.

Seven L6 chondrites were collected in the

Reckling Peak area during the 1980-1981 field

season; only one, RKPA80202 (544 g) weighs

more than 100 g. All the Reckling Peak specimens except RKPA80215 are identical in texture, mineral compositions, and degree of weathering, and most of them have dark glassy veinlets

containing clear isotropic grains tentatively identified as ringwoodite and majorite; these specimens are probably all pieces of a single meteorite

and can be paired with RKPA78001, 78003,

79001, and 79002. RKPA80215 is much more

weathered than the other Reckling Peak L6

chondrites, and appears to be more heavily

shocked, the mineral grains being comminuted

and traversed by shock veinlets of troilite.

CLASS LL6

FIGURE 44

Four LL6 chondrites were collected from the

Reckling Peak area in the 1980-1981 field season: RKPA80222 (6.9 g), 80235 (261 g), 80238

(18.4 g), 80248 (11.3 g). RKPA80222, 80238,

and 80248 were paired on the basis of macroscopic examination, and this has been confirmed

by the evidence from the thin sections. They

show the brecciated structure characteristic of

many LL chondrites. Chondritic structure is

barely discernible, the specimens consisting of a

granular aggregate of olivine and pyroxene, with

minor amounts of plagioclase and troilite, and a

little nickel-iron; some of the nickel-iron is present as unusually large grains, up to 3 mm. A

small amount of limonitic staining is present

around the metal grains. RKPA80235 differs in

being unbrecciated, having less troilite and

nickel-iron (without limonitic staining), and having somewhat higher Fa and Fs contents in olivine and pyroxene (Fa30 vs. Fa28, FS24 vs. FS23).

FIGURE 44.—Photomicrographs of thin sections of LL6 chondrites (area of each field is 3 X 2

mm): a, RKPA80222; b, RKPA80238. (Chondritic structure is barely discernible, being

obscured by extenisve brecciation and integration with the granular matrix).
40 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 45.—ALHA81021, E6 chondrite, photographed as found; a rounded stone covered

with thin black fusion crust showing flow lines.

CLASS E6

FIGURES 45, 46

ALHA81021 (695 g).—This stone (12 X 9 X

3 cm) is smooth and flat, with thin black fusion

crust with flow lines on the upper surface; the

lower surface is considerably weathered and

some of the fusion crust removed, leaving a

smooth red-brown surface. Only traces of chondritic structure are visible in a thin section, which

consists largely of granular enstatite, with considerable nickel-iron (~20%), minor troilite and

plagioclase, and accessory sinoite (Si2N2O, identified by its high birefringence). Weathering is

extensive, with brown limonitic staining throughout the section. Remnants of fusion crust are

present. Microprobe analyses show the enstatite

is almost pure MgSiO3 (CaO 0.8%, FeO 0.2%,

FIGURE 46.—ALHA81021, E6 chondrite, photomicrograph

of thin section (area of field is 3 X 2 mm); a radiating

enstatite chondrule is enclosed in a field of granular enstatite

(white to gray), nickel-iron and sulfides (black).
NUMBER 26 41

A12O3 0.2%); plagioclase is Ani5Or4; the metal

contains about 2% Si.

Achondrites

EUCRITES

FIGURES 47, 48, 49

At the Allan Hills in 1980-1981 one eucrite

(ALHA80102, 471 g) was collected, and in

1981-1982 several more (ALHA81001, 52.9 g;

81006, 254 g; 81007, 163 g; 81008, 43.8 g;

81009, 229 g; 81010, 219 g; 81011, 405 g;

81012, 36.6 g).

ALHA80102 (12.5 X 8 X 5. cm) has areas of

shiny black fusion crust, except on a fracture

surface; many vugs, ranging in size from less than

1 mm to greater than 1 cm, are present, typical

of Allan Hills polymict eucrites. The interior is

medium gray with mm-sized and larger white,

yellow, and black clasts throughout. ALHA

81001 is a small stone (4.5 X 4.5 X 4.0 cm) with

lustrous black fusion crust on two surfaces; the

interior is highly fractured and is quite unlike

other eucrites in being glassy and smoky gray in

FIGURE 47.—ALHA81006, a polymict eucrite, photographed as found.

color. ALHA81006 (11 X 4.5 X 3.5 cm) is an

elongated stone covered with shiny black fusion

crust except on a fracture surface; this surface

has mm-size patches of fusion crust, indicating a

late breakup in the atmosphere. It is a typical

polymict eucrite and has two notably large clasts

(7 X 11 mm and 15 X 13 mm). ALHA81007

(8.5 X 6 X 2.5 cm) and 81008 (5 X 3.5 X 3 cm)

are similar. ALHA81009 (7 X 5.5 X 3.5 cm) is a

hemispherical stone almost completely covered

with lustrous black fusion crust. ALHA81010(8

X 55.5 cm) is similar. ALHA81011 (8 X 65 cm)

is a rounded stone with scattered remnants of

black fusion crust; it is unusual in containing

numerous large clasts up to 2 cm across. Several

different types are present—typical eucritic

clasts, recrystallized pinkish white clasts, massive

gray clasts—and they range in shape from

rounded to rectangular to lens-shaped.

ALHA81012 (5 X 2 X 3 cm) is a lens-shaped

stone typical of the Allan Hills polymict eucrites.

ALHA80102, 81006, 81007, 81008, and

81010 are very similar in all respects and are

probably paired with previously described Allan

Hills polymict eucrites. The following description of the thin section of ALH A81010 is typical

of all of them. The meteorite is a microbreccia,

consisting largely of angular monomineralic pyroxene and plagioclase clasts up to 4 mm in

maximum dimension, and a few lithic clasts, in a

matrix of comminuted pyroxene and plagioclase.

Transparent brown fusion crust rims part of the

section. The pyroxene is light to dark brown

pigeonite; a few grains show exsolution lamellae.

The lithic clasts have a maximum dimension of

3 mm, and consist of pigeonite and plagioclase

with ophitic and gabbroic textures; one clast

consists of angular pigeonite and plagioclase

grains in a semi-opaque glassy matrix. Microprobe analyses show pigeonite and augite with a

wide range of compositions: Wo5 to Wo36, En2e

to En6i, Fs3i to FS57; plagioclase composition

range is An78 to An93, mean An8g.

ALHA81009 and 81012 resemble each other

closely and are tentatively paired. Thin sections

consist largely of brown grains of pigeonite up

to 1 mm and colorless grains of plagioclase up to
42 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 48.—Eucrites.
NUMBER 26 43

A\;.'

'3 ..' *»-7T ? ^^ ^

FIGURE 49.—Photomicrographs of thin sections of eucrites (area of each field is 3 X 2 mm):

a, ALHA81001; b, ALHA81006; c, ALHA81011; d, ALHA81012; e, RKPA80204;

/, RKPA80224.
44 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

2 mm in a comminuted groundmass of these

minerals. Some lithic clasts, up to 3 mm across,

are present; most show fine-grained ophitic textures, but a few have coarse gabbroic textures.

Microprobe analyses show pyroxene compositions ranging fairly continuously from

Wo3En35Fs62 to Wo4oEn26Fs3o, with the En content showing a limited range (26-40). Plagioclase

composition range is An75 to An93, mean An86.

These eucrites differ from previously described

polymict eucrites from the Allan Hills in the

range and distribution of pyroxene compositions.

ALHA81011 is a breccia of eucritic clasts up

to 10 mm in maximum dimension, the clasts

sitting in a minor amount of dark glass filled with

comminuted grains of pyroxene and plagioclase.

The clasts consist of pyroxene and plagioclase

and show a variety of textures: finely granular,

subophitic, and gabbroic. Microprobe analyses

show pyroxene compositions corresponding to

pigeonite and augite and clustering around

two mean compositions, Wo4En36Fs6o and

Wo35En32Fs33, with a few intermediate values.

Plagioclase has fairly uniform composition, An87

to An9i, mean An88. The meteorite is a eucritic

breccia; although it appears to be polymict, the

uniformity of mineral compositions suggests a

considerable degree of equilibration, and it may

be a genomict breccia.

ALHA81001 appears to be a new type of

eucrite. The thin section is translucent in pale

brown-gray, with some darker areas, giving a

patchy appearance. With crossed polars the material is seen to consist of pyroxene prisms up to

0.5 mm long, mostly with straight extinction, in

a glassy groundmass. No opaque minerals are

present. Microprobe analyses show the pyroxene

has rather uniform composition, averaging

Wo16En4oFs59, with 0.4% A12O3, 0.2% TiO2,

0.9% MnO, and 0.6% Cr2O3. Broad-beam analyses give an approximate bulk composition

(weight percent) as follows: SiO2 (49), A12O3 (14),

FeO (18), MgO (6.7), CaO (10), Na2O (0.2), K2O

(0.1), TiO2 (0.9), Cr2O3 (0.6), MnO (0.7). This

composition agrees with that of an average eucrite except that Na2O is lower (in most eucrites

Na2O is about 0.5%); however, the texture is

quite different from any described eucrite. The

overall impression from the texture is that the

material represents a rapidly quenched melt.

Two eucrites were collected in 1980-1981

near Reckling Peak: RKPA80204 (15.4 g) and

80224 (8.0 g).

RKPA80204 (3X2X 2 cm) is partly covered

with black fusion crust. Two texturally distinct

lithologies were noted on the surface: one is

massive and fine-grained with rounded yellow

clasts, the other appears to be coarser-grained,

with abundant light and dark grains. Thin (1

mm) black veins extend into both textures.

Abundant vugs give the exterior a rough surface.

The thin section shows clasts (up to 6 mm in

maximum dimension) of subophitic intergrowths

of pigeonite and plagioclase, separated by veins

of coarser grained pigeonite and plagioclase. The

plagioclase laths in the clasts range up to 0.5 mm

in length. The pigeonite and plagioclase grains

in the veins average about 0.3 mm in maximum

dimensions. Microprobe analyses show pigeonite

with a limited range of composition (Wo4Fs57En39

to Woi3Fs52En35). Plagioclase ranges in composition from An85 to An94, with a mean of An92.

Accessory ilmenite and titanian chromite (TiO2

10-13%) are present. The relative uniformity of

composition of pyroxene and plagioclase indicates that this specimen may be classified as a

monomict eucrite.

RKPA80224 is a small specimen (3.5 X 1.5 X

1.0 cm) partly coated with shiny black fusion

crust. The thin section shows an ophitic intergrowth of pigeonite and plagioclase, with accessory amounts of tridymite and opaque minerals;

the average grain size of pyroxene and plagioclase is about 1 mm. The pyroxene and plagioclase crystals are somewhat granulated and show

undulose extinction. A little limonitic staining is

present in one area. Microprobe analyses show

pigeonite with an average composition of

WoioFs54En36; some grains show exsolution lamellae of augite with composition Wo44Fs25En30.

Plagioclase ranges in composition from An85 to

An9i, with a mean of An89. The opaque minerals

are troilite, ilmenite and titanian chromite (TiO2

13-15%). The meteorite is a monomict eucrite.
NUMBER 26 45

UREILITES

FIGURES 50, 51

The only ureilite in the 1980-1981 collection

(and the first from the Reckling Peak area) is

RKPA80239, a 5.6 g specimen. Thin patchy

fusion crust is present on all surfaces; areas devoid of fusion crust are crystalline, reddish brown

A 4

FIGURE 50.—RKPA80239, ureilite, photomicrograph of

thin section (area of field is 3 X 2 mm); olivine (white,

without cleavage cracks) and pyroxene (light gray, with

cleavage cracks), bordered by black material consisting

largely of carbon.

FIGURE 51.—ALHA81101, ureilite, photomicrograph of

thin section (area of field is 3 X 2 mm); olivine (white to

gray, showing mosaic structure), bordered by black material

consisting largely of carbon.

in color, and rough in texture. The thin section

shows an aggregate of subhedral to anhedral

grains (0.3-1.5 mm across) of olivine with minor

amounts of pyroxene. The grains are rimmed

with black carbonaceous material. Trace

amounts of troilite and nickel-iron are present,

the latter largely altered to translucent brown

limonite concentrated along grain boundaries.

Microprobe analyses show olivine of uniform

composition (Fai6) with notably high CaO content (0.3-0.4%); the pyroxene is a pigeonite of

composition \V05Fs15En80. This meteorite appears to be relatively lightly shocked compared

to most ureilites.

ALHA81101 is a 119 g specimen, 7.2 X 4.5 X

3 cm, with thick black fusion crust on two sides.

The section shows an aggregate of subhedral to

anhedral crystals of olivine, 1-3 mm across; they

are rimmed with dark carbonaceous material.

Pyroxene, if present, is in small amount. Accessory nickel-iron is present, as minute grains along

crystal boundaries and fractures; it is partly altered to brown limonite. Under crossed polars

the olivine crystals are seen as a mosaic of tiny

grains averaging 0.05 mm across, evidently a

shock effect. Microprobe analyses show olivine

of variable composition, Faio to Fa22, mean Fai9.

This urelite differs from previously described

ureilites from the Allan Hills in the mosaic texture of the olivine.

ACHONDRITE, UNIQUE

FIGURES 52, 53, 54

ALHA81005 (31.4 g).—At the time of collection this specimen was noted as unusual, because

of the greenish glassy fusion crust and the presence of prominent clasts. The stone is rounded,

equidimensional (3 X 3 X 2.5 cm) and the crust

shows flow markings; the interior consists of

abundant angular white clasts up to 8 mm across,

set in a dark glassy matrix. In thin sections the

matrix is a translucent to semi-opaque dark

brown glass and shows flow structure in places;

clast: matrix ratio is approximately 40:60. The

larger clasts are polymineralic, the smaller (less

than 0.3 mm) may be individual mineral grains.
46 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 52.—ALHA81005, anorthositic breccia, showing

fusion crust and brecciated nature of interior.

The clasts consist largely of plagioclase, together

with some pyroxene and occasional olivine; most

of the mineral grains are plagioclase. The clasts

show a variety of textures, including gabbroic,

diabasic, and basaltic; many have been shocked

and partly granulated. Some of the clasts resemble eucrites, but many appear to be more feldspathic than most eucrites. The section is notable

for the complete absence of opaque minerals,

except for a 1 mm metal grain. Microprobe

FIGURE 53.—ALHA81005, anorthositic breccia, after laboratory splitting, showing white anorthositic clasts in dark

glossy matrix.

analyses show that the plagioclase is very Ca-rich,

averaging An97 (range An95 to An98); pyroxene

is variable in composition, Wo 1-41, En 44-79,

Fs 7-47 (richer is En than most eucrite pyroxenes); several grains of olivine, Fa 11-40, were

analyzed. The MnO/FeO ratio in pyroxene

grains differs from that in eucrite pyroxenes and

agrees with that in lunar pyroxenes. The meteorite closely resembles many of the Apollo 16

lunar breccias.

FIGURE 54.—ALHA81005, anorthositic breccia, photomicrograph of thin section (area of field

is 3 X 2 mm): a, section showing remnants of fusion crust and clasts in dark glassy matrix; b,

section showing clasts and small clear glass bead.
NUMBER 26 47

This specimen has been the object of intensive

investigation, the preliminary results of which

were presented at the Fourteenth Lunar and

Planetary Science Conference in Houston in

March 1983. Twenty-two papers were given (the

abstracts have been published as LPI Contribution 501 and are available from the Lunar and

Planetary Institute, 3303 NASA Road One,

Houston, Texas 77058). The results confirmed

and extended the preliminary results recorded

above, and confirmed a lunar origin for this

meteorite. For additional information see Marvin

(p. 95).

Literature Cited

Mason, B., and R.S. Clarke, Jr.

1982. Characterization of the 1980-81 Victoria Land

Meteorite Collections. Memoirs of the National Institute of Polar Research (Japan), special issue,

25:17-33.

Scott, E.R.D., GJ. Taylor, P. Maggiore, K. Keil, S.G.

McKinley, and H.Y. McSween

1981. Three CO3 Chondrites from Antarctica—Comparison of Carbonaceous and Ordinary Type 3

Chondrites. Meteoritics, 16:385.

Van Schmus, W.R., and J.A. Wood

1967. A Chemical-Petrographic Classification for the

Chondritic Meteorites. Geochimica et Cosmochimica

Ada, 31:747-765.
Descriptions of Iron Meteorites

and Mesosiderites

RoyS. Clarke, Jr

This section provides brief descriptions of two

octahedrites, a hexahedrite, an ataxite, and a

mesosiderite collected during the 1980 and the

1981 field seasons. The descriptions are preliminary and based largely on material prepared for

publication in the Antarctic Meteorite Newsletter.

Also included is a well-studied mesosiderite, RKP

A79015, from the 1979 season that was not

included in the previous publication in this series.

Octahedrites

RKPA80226 (160 g).—This dark reddish

brown specimen (4.3 X 3.2 X 2.8 cm) from the

Reckling Peak area is slightly smaller than a hen's

egg and is more irregularly shaped. The top

surface is covered with pits 2 to 3 mm in length,

and it is gently and uniformly convex. Distribution of pits seems to have been controlled in part

by the internal Widmanstatten structure. This

surface, and the bottom surface, have been

strongly affected by terrestrial weathering. The

bottom surface is less uniform in shape and more

convex. Part of it has a pattern of pits similar to

that on the top. However, much of the bottom

surface is dominated by a pattern of parallel

ridges approximately 1 mm apart standing out

in relief, an expression of the Widmanstatten

structure of the material.

A median slice of approximately 6 cm2 was

Roy S. Clarke, Jr., Department of Mineral Sciences, National

Museum of Natural History, Smithsonian Institution, Washington,

D.C. 20560.

polished and microetched. This revealed a heataltered zone surrounding the edge of the slice as

deep as 3.5 mm in one area. A well-developed

Widmanstatten pattern is present with a kamacite

band width in the 1.2 mm range. The length/

width ratio for these lamellae is about 7. Some

Neumann bands are present in the kamacite, as

are rhabdites, grain-boundary schreibersites and

subgrain boundaries. No epsilon structure or

troilite was observed. Taenite bands occupy

much of the kamacite grain boundaries, and taenite-kamacite and plessite fields are present. The

plessite areas are mainly pearlitic, suggesting the

possibility that the entire specimen is heat-altered. It is a medium octahedrite containing 8.5

wt.% Ni.

ALHA81014 (188 g).—This specimen (6.5 X

3 X 2 cm) from the Allan Hills is an irregularly

shaped individual somewhat resembling a fish. It

is covered with a uniformly pitted, dark reddish

brown, iridescent, secondary iron oxide coating.

A surface area of approximately 4.5 cm3 was

microetched. The section was taken perpendicular to the long axis of the specimen near the

more massive end. The edge of the section contains a thin, intermittent border of oxide. Below

this is a heat-altered zone up to 1 mm thick that

is present, with the exception of a few small gaps,

around the complete section. Remnant fusion

crust was not observed. Kamacite has a rather

uniform matte surface at low magnification that

can be resolved with higher magnification to a

fine epsilon-decomposition structure. A system

of wider than average kamacite lamellae, con49
50 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

taining frequent centered schreibersites in the

100 X 200 ixm size range, is a prominent feature.

Kamacite lamellae, free of centered schreibersites, have widths in the 0.3 mm range. Plessite

fields occupy approximately two-thirds of the

surface. Interiors of larger fields contain cellular

plessite framed in martensite with taenite borders. Narrow plessite fields have only martensitic

areas with taenite borders. Schreibersite is also

occasionally present at taenite borders, and as

grain boundary schreibersite bridging adjoining

plessite areas. Occasional 5 to 10 nm schreibersites are present within plessite fields. Other inclusions were not observed. The specimen is a

fine octahedrite distinct from ALHA78252, the

previously identified fine octahedrite from the

Allan Hills.

Hexahedrite

ALH A81013(17.75 kg).—The highly distinctive external appearance of this specimen (16 X

16X11 cm) from the Allan Hills suggests that it

is a fragment that separated during atmospheric

breakup from a larger mass with cubic cleavage

(Figure 55). Its shape is that of a cube that has

been shortened along one axis by severe and

irregular ablation-sculpturing of one face. This

face is the only one that is deeply sculptured with

thumb-size regmaglypts, giving the impression

that it was part of the exterior surface prior to

fragmentation (Figure 55a). Its opposite face is

approximately square, with slightly rounded

edges, and appears to have been the leading

surface during late stage ablation (Figure 55b).

All surfaces are covered with a thin reddish

brown coating of secondary oxides, which are

somewhat thicker within the deeper depressions

of regmaglypts. Thin cracks several centimeters

long are present on all surfaces and tend to

parallel the cubic planes of the specimen.

A median slice was removed perpendicular to

the square section of the specimen and parallel

to opposite sides. One side of the slice was polished and macroetched, resulting in an area of

approximately 140 cm2 available for examination

at low magnification. The matrix appears to be

single-crystal kamacite that etches to a dull finish,

atypical for hexahedrites. Several small troilitedaubreelite inclusions are present, as are a few

small schreibersites. Slight variations in kamacite

reflectivity appear to be due to tiny schreibersites

that are unresolvable at low magnification. The

most prominent surface feature is the system of

orthogonal cracks mentioned above. They penetrate into the interior of the specimen. Neumann bands are absent. This cursory examination suggests that the meteorite is a hexahedrite

of somewhat unusual metallography. It probably

represents a separate fall, distinct from the typical hexahedrite ALHA78100.

Ataxite

ALHA80104 (882 g).—This specimen (11 X

7 x 4 cm) from the Allan Hills is an irregularly

shaped individual. One prominently rounded

surface appears to have been ablation-shaped,

and a second fairly large and comparatively

smooth surface appears to have been the underside while the specimen was exposed at the surface of the ice. The meteorite is covered with a

fairly uniform dark reddish brown iron oxide,

and no fusion crust seems to remain. There are

several deep linear incisions into the body of the

meteorite that are possibly due to either preferential ablation or weathering of schreibersite inclusions exposed at the surface.

A microetched surface area of approximately

7 cm2 shows a heat-altered zone over part of the

external surface of the specimen. The metallographic matrix is a martensitic plessite. Kamacite

spindles less than 0.1 mm wide, and generally

less than ten times their width in length, are

FIGURE 55.—ALHA81013 is a hexahedrite that appears to

have broken out of a larger mass during passage through

the atmosphere, (a) This view looks straight down on the

top surface of the specimen (as it lay on the ice sheet). This

single deeply sculptured face was probably ablated prior to

separation from a larger mass. The square outline of the

specimen is 16 cm on an edge, (b) A tilted view of the bottom

surface; a somewhat modified cube face is still evident, as is

ablation rounding of edges. Cracks following cube directions

may be seen in both photographs.
NUMBER 26 51
52 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

moderately uniformly distributed in a vague

Widmanstatten pattern orientation. The kamacite spindles frequently enclose small schreibersites. Three large schreibersite areas are enclosed

in swathing kamacite as wide as 0.2 mm. The

largest such area is 8 mm long. Weathering has

penetrated 0.5 cm into the mass in one area. The

specimen is an ataxite containing 15.9 wt. % Ni,

and it is distinct from ALHA77255, the previously known ataxite from the Allan Hills.

Mesosiderites

RKPA79015 (10.0 kg).—This specimen (26 X

18X13 cm) from the Reckling Peak area is a

dense mass that has undergone severe external

weathering, resulting in an appearance similar to

that of many weathered iron meteorites. It is

covered with reddish brown iron oxide that is

layered in places and thick enough to flake off in

centimeter-size pieces. No fusion crust remains,

and the original shape of the specimen has undoubtedly been somewhat modified. Occasional

cleavage faces of large pyroxene crystals are exposed. It has been described as a mesosiderite by

Prinz et al. (1982) and Clarke and Mason (1982).

The specimen has been divided into two pieces

under clean conditions in a controlled atmosphere at the Antarctic Meteorite Curatorial LabFIGURE 56.—RKPA79015, a median slice 15.5 cm wide revealing heterogeneous distribution

of minerals and a brecciated structure. The etched surface reveals large areas of metal and

sulfide, large areas of orthopyroxene that contain material that grades from very coarse to

finely crystalline, and areas rich in troilite that also contain some metal and pyroxene.
NUMBER 26 53

oratory, Lyndon B.Johnson Space Center, Houston. One piece remains in the protective environment in Houston. The other piece weighing 5.52

kg was sent to the Smithsonian Institution for

preliminary characterization and distribution to

interested scientists.

The brecciated and heterogeneous character

of RKPA79015 is shown in Figure 56, a photograph of the polished and etched surface of the

slice. The meteorite is composed of major

amounts of metal, orthopyroxene, and troilite,

each with associated minor or trace minerals.

The three major minerals tend to be in close

association with each other, even though in given

areas one mineral may predominate over the

other two.

The silicate minerals present are orthopyroxene of uniform composition (Wo2En74Fs24) and

calcium-rich plagioclase of somewhat variable

composition (An86 to An94). Pigeonite and olivine

have been looked for and not found. Chromite

containing A12O3 7.0%, MgO 1.8%, MnO 1.6%,

and TiO2 0.5% is present, as is merrillite

(Ca9MgNa(PO4)7). The bulk metal composition

is 9.87% Ni, 0.52% Co, 0.15% P, and 2.14%

FeS. Metallic areas consist of polycrystalline kamacite with grain boundaries containing cloudy

taenite and schreibersite. Cloudy taenite areas

have thick borders of tetrataenite. These metallographic associations indicate a low temperature

cooling history identical to that of other wellknown mesosiderites. RKPA79015 is apparently

paired with four other silicate-rich fragments

from the same area: RKPA80229, 80246,

80258, and 80263.

ALHA81059 (539 g).—The exterior of this

specimen (9.5 X 5 X 5.5 cm) from the Allan Hills

is severely weathered. Close examination revealed cleavage surfaces of large silicate crystals

within the secondary oxidation products, suggesting that the specimen is a mesosiderite.

A polished thin section consists largely of orthopyroxene clasts ranging up to 10 mm in maximum dimensions, together with about 30% of

nickel-iron in grains up to 0.6 mm; a little troilite

is present. The meteorite is extremely weathered

and seamed with brown limonite. Microprobe

analyses shows that the orthopyroxene is somewhat variable in composition, ranging from Fs25

to Fs32, with mean of Fs28; mean weight percent

CaO is 1.2, MnO 0.7, A12O3 0.6, TiO2 0.2. Small

amounts of olivine (Fa28), plagioclase (An93), merrillite, and an SiO2 phase (probably tridymite)

were detected with the microprobe. The metal

consists largely of kamacite. Tetrataenite-cloudy

taenite associations are concentrated mainly at

kamacite-silicate boundries. Schreibersite is

either enclosed in the tetrataenite-cloudy taenite

areas or in contact with them. The meteorite is

a mesosiderite, the second from the Allan Hills;

it appears to be different from the previous one,

ALHA77219 (Agosto et al., 1980; Prinz et al.

1980).

ALHA81098 (60.9 g).—This sample consists

of two fragments (4 X 4 X 1.5; 4 X 3.4 X 1 cm)

that are similar to ALHA81059 in mineralogy,

texture, and weathering, and probably should be

paired with it.

Literature Cited

Agosto, W.N., R.H. Hewins, and R.S. Clarke, Jr.

1980. Allan Hills A77219, the First Antarctic Mesosiderite. In Proceedings of the Eleventh Lunar and

Planetary Science Conference, pages 1027-1045.

New York: Pergamon Press.

Clarke, R.S., Jr., and B. Mason

1982. A New Metal-Rich Mesosiderite from Antarctica,

RKPA79015. Memoirs of the National Institute of

Polar Research (Japan), special issue, 25:78-85.

Prinz, M., C.E. Nehru, and J.S. Delaney

1982. Reckling Peak A79015: An Unusual Mesosiderite.

In Lunar and Planetary Science XIII, page 631.

Houston: Lunar and Planetary Institute.

Prinz, M., C.E. Nehru, J.S. Delaney, G.E. Harlow, R.L.

Bedell

1980. Modal Studies of Mesosiderites and Related

Achondrites, Including the New Mesosiderite

ALHA 77219. In Proceedings of the Eleventh Lunar

and Planetary Science Conference, pages 1055-1071.

New York: Pergamon Press.
Petrology and Classification of

145 Small Meteorites from

the 1977 Allan Hills Collection

Susan G. McKinley and Klaus Keil

Introduction

We have studied 145 previously undescribed,

small meteorites weighing <150 g from the 1977

Allan Hills Antarctica collection. These meteorites are part of the 350 samples collected by

scientists from the United States and Japan during the 1977-1978 field season (Cassidy, 1980).

Because of their small sizes, these and other

specimens in the 1977 collection weighing <150

g were initially set aside and only later allocated

to us as a suite of 145 samples. The allocation

strategy was as follows: Except for a few meteorites that appeared unusual to the field party

and were allocated for preliminary description

and classification to B. Mason, each specimen

weighing <150>15g (although the largest specimen weighed 174.5 g) was equally split between

the U.S. Antarctic Meteorite collection curated

at the Lyndon B. Johnson Space Center, Houston, Texas, and the Japanese Antarctic Meteorite

Collection at the National Institute of Polar Research, Tokyo, Japan. Of each of these specimens, we were allocated a few grams for our

studies. Meteorites weighing <15 grams were not

split but were divided in equal numbers between

the U.S. and Japanese collections. Each of those

meteorites remaining in the U.S. collection was

allocated to us in total for study and further

distribution to interested investigators.

Susan G. McKinley and Klaus Keil, Department of Geology and

Institute of Meteoritics, University of New Mexico, Albuquerque,

New Mexico 87131.

We carried out mineralogic and petrographic

studies of all 145 meteorites. In addition, we

initiated studies by others on selected specimens

from this suite. P. Signer and co-workers are

carrying out noble-gas measurements on four

type 3 ordinary chondrites, ALHA77011,

77013, 77176, and 77197, and the enstatite

chondrite ALHA77156. Thermoluminescence

sensitivity measurements were made by Sears and

Weeks (1983) on the same five meteorites. The

carbonaceous chondrite (C3O), ALHA77029,

was analyzed by INAA (Kallemeyn and Wasson,

1982) and a specimen of ALHA77011 (namely

ALHA77050) will be analyzed by J.T. Wasson

and co-workers. Several specimens of ALHA

77011 and a pyroxene-rich chondrule from the

same meteorite are being analyzed by R.N. Clayton for oxygen isotopic compositions, and 23

equilibrated ordinary chondrites are being studied by J.R. Arnold and co-workers for tracks,

radionuclides (53Mn,

 36C1, 10Be, 26A1), and rare

gases in a search for objects that may have

been in space as small meteoroids. Neon and

xenon isotopic compositions of graphite-magnetite inclusions in ALHA77011 (specimen ALHA

77050) were measured by Caffee et al. (1982).

We have also loaned polished thin sections of

various specimens to several investigators for optical microscopy and electron microprobe studies.

Our mineralogic and petrographic studies

show that all 145 meteorites in our suite are

chondrites (Table 3). Of those, 120 are equili55
56 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

brated (i.e., petrologic types 4 to 6) ordinary

chondrites, with two belonging to the LL group,

16 to the L group, and 102 to the H group. The

remaining 25 specimens include 19 that are

paired with ALHA77011, an unusual L3 chondrite containing a graphite-magnetite matrix in

addition to the common silicate ("Huss") matrix

(Huss et al., 1981). Three specimens are unpaired L3 chondrites (Table 4), two are paired

enstatite chondrites (EH4), and another is a carbonaceous chondrite (C3O).

Here we summarize the classification of all

meteorites in our suite and report in more detail

on the less common types, namely the carbonaceous chondrite, the four type 3 ordinary chondrites, and the enstatite chondrite. We conclude

that study of large suites of small Antarctic meteorites is exceedingly worthwhile and rewarding. Most specimens are relatively fresh and unweathered, and their large numbers increase the

likelihood of discovering new, unusual, and rare

meteorite types, such as the unique graphitemagnetite bearing L3 ordinary chondrite and

the enstatite chondrite (the first from the Allan

Hills and only the fourth from Antarctica). Furthermore, these small meteorites may be attractive for special studies, such as the search for

objects that travelled in space as small meteoroids. We therefore urge continued collection

and study of large suites of small Antarctic meteorites.

ACKNOWLEDGMENTS.—We thank the Antarctic Meteorite Working Group for allocating to

us the 145 meteorites studied here; Robbie Score

(JSC) for valuable aid in preparing the specimens

for us; G. Gomez and Jackie Allen for preparing

polished thin sections; and E.R.D. Scott and GJ.

Taylor for valuable collaboration, assistance, and

discussions throughout the course of this project.

This work was supported in part by the National

Aeronautics and Space Administration, Grants

NGL32-004-064 and NAG-9-30 to K.K.

Method of Study

Each specimen weighing <15 g, which was

allocated to us in its entirety, was macroscopically

described before cutting. This description includes a sketch of the external shape of the

specimen and notes the external appearance of

the meteorite, including preservation of the fusion crust, color, degree of weathering, veining,

etc. After cutting for preparation of polished thin

sections, detailed sketches of the cuts were made

and their weights were recorded. A similar brief

macroscopic description was also made of the

small aliquots we received of meteorites weighing

>15 g. Detailed information on their main

masses is not available from us but is available

from the Curatorial Office at the Johnson Space

Center. At least one polished thin section was

prepared of each specimen, using special procedures (i.e., no water) in the preparation of sections of meteorites containing water-soluble

phases (e.g., the enstatite chondrite). Polished

thin sections were studied in the optical microscope in transmitted and reflected light, and

olivine and pyroxene compositions of equilibrated ordinary chondrites were determined

with an automated ARL EMX-SM electron microprobe. Electron microprobe analyses of these

and other phases were carried out using the

procedures of Bence and Albee (1968) and Keil

(1967), and standards and analytical conditions

employed were essentially those listed in Fodor

and Keil (1976). Analyzed olivine and pyroxene

grains were chosen at random, and ordinary

chondrites were then classified on the basis of

their ranges and mean olivine and pyroxene Compositions and their textural characteristics, using

a modified version of the Van Schmus and Wood

(1967) scheme (Gomes and Keil, 1980:31-32).

More detailed microscopic and electron microprobe studies were made on the carbonaceous

chondrite, the type 3 ordinary chondrites, and

the enstatite chondrite.

Chondrites

CLASS C3O

ALHA77029 (1.4 g).—This small stone measured 15x7x 4 mm and was covered (except

on one flat side) by dark gray, frothy fusion crust.

No chondrules were visible on the surface, and
NUMBER 26 57

the only external weathering noted was in a small

pit in the fusion crust.

Microscopic and electron microprobe studies

(Scott, Taylor, et al., 1981) indicate that this

meteorite is an unpaired Ornans-type carbonaceous chondrite (C3O). It has the typical texture

of C3O meteorites and contains (in the terminology of McSween, 1977) abundant chondrules

<0.5 mm in apparent diameter and lithic fragments and inclusions embedded in a dark matrix

(Figure 57). These constituents occur in proportions typical for C3O chondrites, except that the

matrix to chondrule ratio is the highest (0.79)

yet reported (Scott, Taylor, et al., 1981).

Matrix and mineral compositions are typical

of C3O chondrites. The matrix is high in FeO

and NiO, and olivine and pyroxene compositional histograms obtained on randomly selected

grains have the characteristic means and broad

ranges of C3O chondrites (Scott, Taylor, et al.,

1981). The olivine histogram has no pronounced

peak and is similar to that of Ornans (Van

Schmus, 1969).

Based on compositional evidence (Scott, Taylor, et al., 1981), we have classified this meteorite

as a moderately metamorphosed C3O chondrite

of stage II (McSween, 1977). The mean fayalite

composition (Fa2.s) is intermediate between the

least and most equilibrated C3O chondrites. Similarly, kamacite has intermediate Cr, Co, and Ni

contents, resembling those of the C3O chondrites Felix and Lance (McSween, 1977).

CLASS EH4

ALHA77156 (17.7 g); ALHA77295 (141 g),

total weight 158.7 g. ALHA77156 is the first

enstatite chondrite recovered from the Allan

Hills; the second, ALHA81021, an EL6, was

found in 1981 (Schwartz and Mason, 1983). Two

others from Antarctica are Yamato 69001, an

EH4-5 (Okada, 1975) and RKPA80259, an EH5

(Score et al., 1982). We have paired ALHA77156 with ALHA77295, based on mineral

abundances and compositions. Following the recommendations of the Committee on Meteorite

Nomenclature of the Meteoritical Society (Graham, 1980), this chondrite should be referred to

as ALHA 77156.

ALHA77156 contains well-defined chondrules typical of type 4 chondrites (Figure 58).

Silicate phases include clinoenstatite and minor

olivine, albite, and silica. Kamacite, niningerite,

and zincian daubreelite are present in abundances typical of EH4 chondrites. Troilite, perryite, schreibersite, and oldhamite are more

abundant than in other EH4 chondrites. Accessory djerfisherite, sphalerite, and weathered

caswellsilverite are also present.

Total Fe concentration (313 mg/g), calculated

from mineral compositions and modal abundances, falls within the EH range (Sears, Kallemeyn, et al., 1982). Mineral compositions typically lie within the ranges of EH4 chondrites.

Those mineral compositions that are outside of

the range are usually close to the mineral compositions in Kota-Kota (EH4) (Keil, 1968). For

example, in both ALHA77156 and Kota-Kota,

the Ni content is higher in schreibersite and

lower in kamacite than the range for these minerals in other EH4 chondrites. Using the niningerite-oldhamite-troilite geothermometer of

Skinner and Luce (1971), the calculated equilibration temperatures for niningerite in

ALHA77156 and Kota-Kota agree well (475°C

and 485°C, respectively). These are the lowest

temperatures determined for EH4 chondrites.

Clinoenstatite luminesces in various shades and

intensities of red and blue under electron bombardment. Random analyses of enstatite within

and outside of chondrules show that the bright

blue grains usually have very low (<0.1%) MnO

and Cr2C>3, whereas dull blue and red grains have

a broad range of MnO and Cr2O3 contents. Our

work on minor-element distributions in enstatite

of ALHA77156 and other enstatite chondrites

(McKinley et al., 1982, 1983) provides convincing evidence against the model of Leitch and

Smith (1980, 1981, 1982), in which enstatite

chondrites formed by collision of two planetesimals, one consisting of red and the other of blue

luminescing enstatites, and mechanical aggregation of the debris.
58 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 57.—Photomicrograph of the C3O chondrite, ALHA77029, showing chondrules and

irregular inclusions in a dark matrix. Transmitted plane-polarized light. Scale =1.5 mm.

FIGURE 58.—Photomicrograph of the EH4 chondrite, ALHA77156 (paired specimen

ALHA77295,8), showing fine-grained opaque phases (light gray and white) and Fe.Ni metalsulfide aggregates. Reflected light. Scale = 2.7 mm.
NUMBER 26

59

CLASS L3

ALHA77011 (total weight 6338 g).—We have

paired 19 of the 145 small meteorites studied

here with 15 larger specimens from the 1977-

1978-1979 Allan Hills collection, based on the

presence of unique graphite-magnetite aggregates (McKinley et al., 1981). Cassidy (1980) had

previously suggested that, on the basis of field

relationships, nine of the larger specimens may

be paired. ALHA77011 is one of the larger

specimens and is the lowest-numbered object of

the paired specimens. Thus, according to the

recommendation of the Committee on Meteorite

Nomenclature of the Meteoritical Society (Graham, 1980), this chondrite shower should generically be referred to as ALHA77011, although

this specimen is not part of the collection of small

meteorites described here.

ALHA77011 is a unique chondrite, characterized by the presence of abundant matrix and

inclusions (3.2 vol. %), consisting of aggregates

of micron-to-submicron-sized graphite and magnetite, in addition to the typical "Huss" silicate

matrix (Huss et al., 1981). This meteorite contains graphite-magnetite in higher amounts than

most type 3 ordinary chondrites (which normally

have <0.1 vol. %) but in much lower proportions

than the type 3 ordinary chondrite clasts with

graphite-magnetite matrices (14-36 vol. %)

found in some regolith breccias (Scott, Rubin, et

al., 1981). In all other respects, ALHA77011 is

typical of type 3 ordinary chondrites. It has

sharply defined chondrules embedded into a matrix consisting of about equal amounts of finegrained opaque and recrystallized silicate matrix

(Figure 59). Olivine compositions range from Fai

to Fa37 (percent mean deviation is 39) and lowCa pyroxene ranges from Fsi to Fs40 (percent

mean deviation is 56). The percent mean deviation was calculated from FeO weight concentrations in olivine and pyroxene. Metallic Fe,Ni has

significant amounts of Cr and Si and widely

varying Co contents, indicating that the meteorite is one of the least-metamorphosed type 3

ordinary chondrites (Afiattalab and Wasson,

1980). Using the criteria of Sears, Grossman, et

al. (1982), we have classified ALHA77011 as a

petrologic type 3.2±0.2 (McKinley et al., 1981),

whereas Sears, Grossman et al. (1982) classified

it as a petrologic type 3.5± 0.1. Additional

mineralogic-petrographic studies of the meteorite have been carried out by Ikeda et al. (1981),

Fujimaki et al. (1981), and Nagahara (1981).

Classification of ALHA77011 as an L-group

chondrite was originally proposed by King et al.

(1980), based on petrographic studies. This classification was confirmed by the bulk analysis of

Jarosewich (1980), which yielded total Fe of

20.77 wt.% and an Fe/SiO2 weight ratio of 0.55,

well within the L-group range. The Ni/Mg

(0.086), S/Mg (0.15), and Fe/Mg (1.52) ratios

also fall within the L fields of Jarosewich and

Dodd(1981).

ALHA77013 (23.0 g).—This meteorite contains very well-defined, densely packed chondrules in a matrix of recrystallized Huss silicate

matrix and fine-grained silicates (Figure 60).

Typical chondrule types are present, including a

barred olivine chondrule with interstitial glass.

Olivine composition ranges from Fa9.o to Fa27.e

(mean Fai8.7), with a standard deviation of the

analyses (mole % Fa) of 3.8 and a percent mean

deviation of 16.6. Pyroxene ranges from Fs22to

Fs35 (mean FS13.1), with a standard deviation of

the analyses (mole % Fs) of 7.9 and a percent

mean deviation of 47.3. We classify ALHA77013

as an L3 chondrite, based on its low metallic

Fe,Ni content of 3 vol. % and its texture. The

olivine and pyroxene compositions (Figure 61)

are less conclusive and trend more towards the

H group. However, these data suggest that the

meteorite is not paired with any other from

Victoria Land.

ALHA77013 has been classified as a petrologic type 3.5, based on thermoluminescence sensitivity (Sears and Weeks, 1983). The coefficient

of variation of Fa is 20.5, which is within the

range for type 3.7 (Sears, Grossman, etal., 1982).

ALHA77176 (54.4 g).—This unpaired meteorite contains very well-defined chondrules in a

matrix of opaque and recrystallized Huss silicate

matrix (Figure 62). A few large lithic inclusions
FIGURE 59.—Photomicrograph of the L3 chondrite, ALHA77O11 (paired specimen

ALHA77052) showing abundant, well-defined chondrules. Transmitted plane polarized light.

Scale = 2.5 mm.

:%,.. '•**- '-.;,:' -y.mr ' "• v?

• * -•• - ». -

FIGURE 60.—Photomicrograph of the L3 chondrite, ALHA77013, showing abundant, welldefined chondrules. Transmitted plane-polarized light. Scale = 3.0 mm.
NUMBER 26 61

are present and the chondrules are commonly

irregular in shape. Typical chondrule types are

present and clear glass is common in some. Troilite occurs as shock-melted, "fizzed" intergrowths

with metallic Fe,Ni and as individual polycrystalline grains.

Olivine and pyroxene in this meteorite are

more variable in composition (Figure 61) than in

any other Antarctic ordinary chondrite, with the

possible exception of ALHA76004 (Scott, this

volume), indicating that it is less equilibrated.

Olivine ranges from Fao.3 to Fa33.5 (mean Fa 12.4),

with a standard deviation of the analyses (mole

% Fa) of 8.3 and a percent mean deviation of

54.3. Pyroxene ranges from Fsi.8 to Fs36.7 (mean

Fsi2.2)> with a standard deviation of the analyses

(mole % Fs) of 8.9 and a percent mean deviation

of 61.2. We have classified the meteorite as an L

0

OLIVINE

ALHA770I3

H L

LOW-Ca PYROXENE

ALHA770I3

H L LL

10 20

Mole% Fa

20

Mole% Fs

FIGURE 61.—Histograms of electron microprobe analyses of randomly selected olivines (in

mole % fayalite), and low-Ca pyroxenes (in mole % ferrosilite), in three L3 chondrites from

the Allan Hills. Also given are the number of analyses (N) and their standard deviation (a).

Compositional ranges for equilibrated H, L, and LL group chondrites are from Gomes and

Keil(1980).
FIGURE 62.—Photomicrograph of the L3 chondrite, ALHA77176, showing well-defined

chondrules, a large broken chondrule, and an inclusion. Transmitted plane-polarized light.

Scale = 2.0 mm.

FIGURE 63.—Photomicrograph of the L3 chondrite, ALHA77197, showing abundant, welldefined chondrules. Transmitted plane-polarized light. Scale = 3.0 mm.
NUMBER 26 63

group chondrite, based on its low metallic Fe,Ni

content (5 vol. %), and as a petrologic type 3,

based on its texture and variable olivine compositions. Olivine and low-Ca pyroxene have significantly higher mean MgO and CaO contents

than ALHA76004 (see Scott, this volume), indicating less equilibration. ALHA77176 has been

classified as a petrologic type 3.2, based on thermoluminescence sensitivity (Sears and Weeks,

1983). The coefficient of variation for Fa in

olivine is 67, which indicates a petrologic type

<3.4 (Sears, Grossman, et al., 1982).

ALHA77197 (20.3 g).—This meteorite contains very well-defined chondrules in a matrix of

fine-grained silicates and recrystallized Huss silicate matrix (Figure 63). Typical chondrule types

are present, including two with pinkish brown

glass.

Olivine composition ranges from Fai0.4 to

Fa27.4 (mean Fa24.4), with a standard deviation of

the analyses (mole % Fa) of 3.0 and a percent

mean deviation of 6.2. Only four of 67 olivine

analyses fall outside the range for olivine of L

group chondrites (Figure 61); two of these are

from the same grain. Pyroxene ranges from Fs40

to Fs2i.o, with a standard deviation of the analyses

(mole % Fs) of 5.1 and a percent mean deviation

of 30.7. We therefore classify ALHA77197 as

an L3 chondrite based on low metallic Fe,Ni

content, olivine and pyroxene composition, and

texture. The meteorite was classified as a petrologic type 3.6, based on thermoluminescence sensitivity (Sears and Weeks, 1983). This classification may be somewhat too low in petrologic

grade; the coefficient of variation of Fa is 12.3

%, which falls within the range (10-20%) for

petrologic type 3.8 (Sears, Grossman, et al.,

1982).

ALHA77197 is not paired with the other

eight L3 chondrites from Victoria Land. It

is closest in composition to ALHA79022

and RKPA80256. However, the olivine in

ALHA77197 is more magnesian than that in

ALHA79022 and pyroxene is less variable in

composition than that in RKPA80256 (Scott, this

volume). Although there are no mineral compositional data available on ALHA77215, the brecciated texture of this regolith breccia (Score,

personal communication, 1983) rules out pairing

with ALHA77197.

Equilibrated Ordinary Chondrites

(Petrologic Types 4 to 6)

The classifications of 120 equilibrated ordinary chondrites (petrologic types 4 to 6) are given

in Table 3, together with those of the 22 type 3

ordinary chondrites. The criteria we used in

classifying these chondrites are those proposed

by Van Schmus and Wood (1967), as modified

by Gomes and Keil (1980:31-32). The petrologic

characteristics of ordinary chondrites form a continuum from types 3 to 6; thus pigeonholing

chondrites into petrologic types is always somewhat arbitrary, particularly for the higher petrologic types. The main diagnostic criteria we used

in classifying ordinary chondrites into petrologic

types are as follows: type 3, >5 percent mean

deviation in the FeO content of olivine; type 4,

<5 percent mean deviation in the FeO content

of olivine and >20 percent of the total pyroxene

is clinopyroxene; type 5, <20 percent of the total

pyroxene is clinopyroxene, and plagioclase is

common, with grains <50 /im across; and type 6,

plagioclase is abundant and grains are >50 pm

across.

Discussion

The main motivation for studying this large

collection of small meteorites stems from our

previous experience with large suites of randomly collected, small rake samples of lunar

rocks (e.g., Dowty, Prinz, et al., 1973; Dowty,

Conrad et al., 1973; Warner et al., 1975). Our

experience is that systematic study of such suites

increases the probability of discovering new and

rare rock types and that it facilitates comparison

of rocks via large data bases obtained in one

laboratory. Our optimism was justified. We identified a new meteorite type, ALHA77011, a type

3 ordinary chondrite with a graphite-magnetite
64 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

matrix, in addition to the common Huss silicate

matrix. Comparison of specimens in this suite

enabled us to pair 19 specimens of ALHA77011

from among the 145 meteorites studied here

with 15 larger specimens from the 1977-1978-

1979 Allan Hills collections. We further discovered a number of rare meteorites, such as the

C3O carbonaceous chondrite (ALHA77029),

two paired specimens of an EH4 enstatite chondrite (ALHA77156, ALHA77295), and three

unpaired petrologic type 3 ordinary chondrites

(ALHA77013, ALHA77176, ALHA77197).

Concerns that these small meteorites would be

too weathered for scientific study proved to be

largely unfounded. Comparison of paired small

and large members of a fall indicates that the

small objects are not significantly more weathered than the larger ones, at least not in case of

the meteorites we studied. Thus, the success in

discovering new and rare meteorites in this suite

strongly argues for the need to continue to collect very small meteorites in Antarctica, to carefully document their field relationships, and to

make them available for study.

In Table 4 we summarize the classification of

all 142 ordinary chondrites (petrologic types 3

to 6) studied here. We compare this suite with

the classifications of mostly larger types 3 to 6

ordinary chondrites from the 1976-1979 collections from the Allan Hills, Antarctica (Score et

al., 1981), the ordinary chondrite falls and finds

(Motylewski, 1978), and falls only (Wasson,

1974) from the rest of the world. The purpose

of this comparison is to see if there are any

similarities or differences in classifications of

small ordinary chondrites in the 1977 Allan Hills

collection when compared to mostly larger meteorites from the same location in Antarctica and

from locations around the world, both for falls

and finds together and for observed falls only.

Such a comparison may allow us to make inferences as to the arrival and collection of generally

rather recent arrivals of meteorites to Earth (e.g.,

as represented among falls and finds from the

rest of the world), with the generally older meteorites (in terms of terrestrial residence time),

Nomenclature for Shock Facies

(from Dodd and Jarosewich, 1979:340)

a = Olivine fractured; plagioclase at least 50% undeformed; melt pockets not present.

b = Olivine fractured and with undulose extinction; plagioclase at least 50% undeformed; melt pockets not present.

c = Olivine fractured and with undulose extinction;

plagioclase at least 50% deformed, but maskelynite

and melt pockets absent.

d = Olivine fractured and with mosaic extinction;

plagioclase entirely deformed and/or maskelynite;

melt pockets present.

preserved in the deep-freeze of the Antarctic ice

(Evans et al., 1982). It should be noted at the

outset that such comparisons are considerably

affected by many uncertainties due to serious

sampling errors and statistical biases. Uncertainties result from biases in the removal of meteorites from their parent bodies, orbital considerations, possible selection effects during atmospheric entry and survival on the ground, pairing

of Antarctic finds, and relatively small numbers

of meteorites available for comparison. It would

appear, however, that the falls summarized by

Wasson (1974) would most closely represent the

distribution of more recent arrivals to Earth of

ordinary chondrites. Furthermore, the ordinary

chondrite types represented among the Allan

Hills collections (Score et al., 1981) might be

expected to be similar to those in the suite of

142 ordinary chondrites studied here. However,

as pointed out above, extreme caution must be

exercised in such comparisons. Nevertheless,

some useful information appears to emerge from

the comparison, which is summarized here.

First, the percentage of H5 chondrites in our

suite (83%) is much larger than that among the

observed falls (47%; Wasson, 1974). Since there

are at least 17 paired specimens among the H5

chondrites {Antarctic Meteorite Newsletter, 1981) of

Score et al. (1981), we conclude that probably

many of our H5 chondrites are also paired, thus

explaining their preponderance over those

among observed falls.
NUMBER 26 65

TABLE 3.—Characterization of small meteorites from the 1977-1978 Allan Hills collection

(n.d. = no data; A = minor; B = moderate; C = severe).

ALH A

77007

77008

77013

77016

77017

77018

77019

77022

77023

77026

77027

77029

77031*

77034*

77036*

77038

77039

77041

77042

77043*

77045

77046

77047*

77049*

77050*

77051

77052*

77054

77056

77058

77060

77063

77066

77069

77070

77073

77076

77078

77079

77082

77084

77085

77087

77089

77091

77092

77094

77096

Weight

(g)

99.3

93.0

23.0

78.3

77.9

51.8

59.8

16.0

21.4

20.3

3.7

1.4

0.5

1.8

8.5

18.8

8.2

16.6

20.4

11.4

17.9

7.6

20.4

7.3

84.2

15.0

112

10.4

12.3

3.7

64.4

2.9

4.9

0.8

18.4

10.1

1.7

7.8

7.8

12.0

44.1

45.9

30.7

7.8

4.2

45.0

6.6

2.5

Class

and

type

H5

L6

L3

H5

H5

H5

L6

H5

H5

L6

L6

C3O

L3

L3

L3

H5

H5

LL6

H5

L3

H5

H6

L3

L3

L3

H5

L3

H5

H4

H5

LL5

H5

H5

L6

H5

H5

H5

H5

H5

H5

H5

H5

H5

L6

H5

H5

H5

H5

Olivine

(mole % Fa)

19.1

24.6

9-28

18.6

18.8

19.0

24.9

19.1

19.1

24.3

25.0

23

n.d.

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

18.0

19.0

25.4

18.4

18.8

19.5

19.5

18.2

19.3

18.8

18.8

19.0

25.5

18.9

18.5

18.5

18.7

Pyroxene

(mole % Fs)

16.7

20.6

1-35

17.1

16.3

17.0

21.4

17.0

16.8

20.7

21.5

2.6

n.d.

n.d.

n.d.

17.1

16.3

25.1

16.0

1-28

17.0

16.7

n.d.

n.d.

n.d.

16.5

n.d.

16.9

16.3

16.1

23.2

16.8

17.4

21.4

16.8

17.7

16.1

16.7

15.8

16.5

16.8

17.6

16.7

21.4

16.1

16.5

16.2

17.1

Degree

of

weathering

B

A

B

B

B

B/C

B/C

A

B

B/C

B/C

A/B

B/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

B

A

B/C

B

A/B

B

B

A

A/B

A/B

B

B

B

B/C

A

B

A

Shock

faciesf

a

c

b

c

c

b

d

c

c

b

d

a

b

b

b

c

c

b

b

b

b

c

b

b

b

b

b

c

b

b

b

c

c

d

b

b

b

b

b

c

b

b

b

b

a

b

b

b

•f Nomenclature following Dodd and Jarosewich (1979:340); see accompanying box on p. 64.
66 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 3.—Continued.

ALHA

77098

77100

77101

77104

77106

77108

77111

77112

77113

77114

77115*

77117

77120

77122

77125

77126

77127

77129

77130

77131

77132

77133

77134

77136

77138

77139

77142

77143

77146

77147

77149

77151

77152

77153

77156

77157

77158

77159

77161

77162

77163*

77166*

77168

77170*

77171

77173

77174

77175*

77176

Weight

(g)

8.0

8.5

3.8

6.3

7.8

0.7

52.3

21.7

2.0

44.5

154

20.8

3.9

4.6

18.7

25.2

3.8

1.7

24.8

25.9

115

18.7

19.1

3.6

2.1

65.9

3.1

39.0

18.2

18.7

25.6

16.9

17.8

12.0

17.7

88.3

19.9

17.0

6.1

29.0

24.3

140

24.7

12.2

23.8

25.8

32.4

23.3

54.4

Class

and

type

H5

H5

H5

H5

H5

H5

H6

H5

H5

H5

L3

L5

H5

H5

H5

H5

L5

H5

H5

H6

H5

H6

H6

H5

H5

H5

H5

H5

H6

H6

H6

H5

H5

H5

EH4

H6

H5

L6

H5

L6

L3

L3

H5

L3

H5

H5

H5

L3

L3

Olivine

(mole % Fa)

18.7

19.2

18.6

18.9

18.8

18.5

19.0

18.7

18.7

19.6

n.d.

24.4

18.5

19.1

17.2

18.3

25.0

18.9

18.9

19.2

19.0

19.0

18.9

19.1

19.2

18.6

18.9

18.7

18.9

19.0

19.1

18.9

18.7

19.2

0.8

18.6

18.9

24.4

19.3

25.3

n.d.

n.d.

19.0

n.d.

18.9

19.1

18.3

n.d.

0.3-34

Pyroxene

(mole % Fs)

16.7

16.4

17.0

16.9

16.5

15.9

16.6

16.7

17.2

17.2

n.d.

21.0

16.0

16.8

15.5

16.2

21.1

16.6

16.5

16.8

16.9

17.0

16.7

16.4

17.0

16.4

17.1

16.2

16.9

16.6

16.9

16.4

16.9

16.7

1.5

15.7

16.9

20.8

17.1

20.9

n.d.

n.d.

16.5

n.d.

17.0

17.0

16.0

n.d.

1-37

Degree

of

weathering

B

A/B

B

A

A/B

A/B

A/B

A

B

B

B/C

A/B

A/B

B

A/B

A/B

B

B

A

A/B

A/B

A

A

A/B

A

A/B

A/B

A/B

A/B

A/B

A/B

A

A

A

A

B

A/B

A/B

B

A

B/C

C

B

B/C

A/B

B

A

B/C

B

Shock

facies

b

b

b

b

c

a

a

a

a

b

b

c

a

b

a

a

d

a

a

b

a

a

c

a

a

b

b

b

a

b

a

a

b

b

b

b

b

c

b

d

b

b

b

b

a

a

b

b

b
TABLE 3.—Continued.

ALH A

77178*

77181

77184

77185*

77186

77187

77188

77193

77195

77197

77198

77200

77201

77202

77205

77207

77209

77211*

77212

77213

77218

77220

77222

77227

77228

77235

77237

77239

77240

77241*

77242

77244*

77245

77246

77247

77248

77251

77253

77265

77266

77267

77275

77279

77291

77293

77295**

77301

77303*

Weight

(g)

5.7

33.0

128

28.0

122

52.2

109

6.7

4.7

20.3

7.3

0.9

15.0

2.7

3.1

4.9

31.8

26.7

16.8

8.4

45.1

69.1

125

16.0

19.3

4.9

4.1

19.0

25.1

144

56.5

39.5

33.4

41.6

44.2

96.1

68.8

23.6

18.3

108

103

24.9

174

5.8

110

141

55.0

78.6

Class

and

type

L3

H5

H5

L3

H5

H5

H5

H5

H5

L3

L6

H6

H5

H5

H5

H5

H6

L3

H6

H5

L5

H5

H4

H5

H5

H5

H5

H6

H5

L3

H5

L3

H5

H6

H5

H6

L6

H5

H5

H5

L5

H5

H5

H5

L6

EH4

L6

L3

Olivine

(mole % Fa)

1-36

20.0

17.8

n.d.

18.8

18.1

18.1

19.0

18.9

10-27

24.4

19.7

18.8

18.6

18.8

17.8

18.8

n.d.

18.9

18.6

23.4

17.7

18.0

18.9

18.5

18.9

18.5

18.7

18.8

n.d.

18.8

n.d.

19.2

19.2

18.8

18.7

25.0

19.2

17.6

19.6

24.7

18.3

18.8

18.9

24.7

0.8

24.9

n.d.

Pyroxene

(mole % Fs)

2-40

17.3

15.9

n.d.

16.0

16.3

16.1

15.7

16.4

4-21

20.6

17.6

15.3

16.6

16.7

16.7

16.4

n.d.

17.0

16.5

19.1

16.0

15.3

16.6

16.3

16.7

15.8

15.9

16.0

n.d.

16.2

n.d.

17.2

16.5

16.4

16.7

21.3

16.9

15.9

17.7

20.9

15.6

17.1

15.9

20.9

1.7

20.9

n.d.

Degree

of

weathering

B/C

B

B

A/B

A/B

A/B

A/B

A

A

A/B

B

C

A

B

B

A/B

B

B/C

A/B

A

A

B

A/B

A

B

A/B

A

B

A

C

B

B/C

A/B

B

A/B

B/C

B

A/B

B

B

A

A

A

A

B

A

A

B/C

Shock

facies

b

a

b

b

b

b

b

b

b

c

d

a

b

b

b

b

b

b

a

a

c

c

b

a

a

b

b

a

b

b

a

b

b

a

b

a

d

c

b

a

c

a

b

b

c

b

d

b

* Paired with A77011.

** Paired with A77156.
68 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 4.—Classification of 142 small ordinary chondrites from the Allan Hills collection

compared to classifications of mostly larger specimens recovered from the Allan Hills in 1976,

1977, 1978, and 1979 (Score et al., 1981) as well as meteorite falls and finds (Motylewski,

1978) and falls only (Wasson, 1974) in the rest of the world.

Class

H3

H4

H5

H6

Total H

L3

L4

L5

L6

Total L

LL3

LL4

LL5

LL6

Total LL

Total H

Total L

Total L L

Total ordinary

chondrites

This paper

No.

0

2

85

15

102

22

0

4

12

38

0

0

1

1

2

102

38

2

142

%

0

2

83

15

100

58

0

10

32

100

0

0

50

50

100

72

27

1

100

Score et al.

No.

4

28

68

30

130

19

1

3

54

77

4

0

3

2

9

130

77

9

216

(1981)

%

3

22

52

23

100

25

1

4

70

100

45

0

33

22

100

60

36

4

100

Motylewski*

No.

11

86

174

86

357

12

30

78

262

382

6

1

12

30

49

357

382

49

788

(1978)

%

3

24

49

24

100

3

8

20

69

100

12

2

25

61

100

45

49

6

100

Wasson (1974)

No.

6

23

53

32

114

9

11

28

117

165

6

1

7

20

34

114

165

34

313

%

5

20

47

28

100

5

7

17

71

100

18

3

20

59

100

36

53

11

100

* Approximately 2% of these chondrites are from Antarctica.

Second, the percentage of H4 chondrites in

our collection (2%) is much lower than in the

collection of Score et al. (1981). At least ten of

the latter appear to be paired (Antarctic Meteorite

Newsletter, 1981), but this is still considerably

higher than the proportion in our suite. It should

be noted that the paired specimens of Score et

al. (1981) all weigh more than 1 kg, whereas ours

weigh less than 150 g. One is tempted to speculate that the shower of the paired H4 chondrites

in the Score et al. (1981) suite yielded predominately large specimens, whereas we studied only

small objects. However, Cassidy (1980) states that

some of their paired H4 specimens were taken

from an area where the smaller objects were

removed by wind on the ground.

Third, the proportion of L3 chondrites in our

and the Score et al. (1981) suite (58% and 25%

of L chondrites, respectively) is biased by the

large ALHA77011 shower when compared to

falls (5%; Wasson, 1974) and falls and finds (3%;

Motylewski, 1978). Our suite contains 19 and

the Score et al. (1981) 15 paired specimens of

the ALHA77011 L3 shower. Hence, the percentage of L6 chondrites in our L suite (32%) is

artificially low when compared to observed falls

(71%). The percentage of L6 chondrites in the

Score et al. (1981) L suite (70%) is high in spite

of the large number of paired L3 chondrites

because at least 20 of the L6 chondrites are also

paired (Antarctic Meteorite Newsletter, 1981). Recalculation, taking into account pairings, would

result in approximately 60% L6 chondrites in

our L suite and 80% in that of Score et al. (1981),
NUMBER 26 69

more in keeping with observed falls (Wasson,

1974).

Fourth, when considering the percentage of

H, L, and LL group chondrites, it is apparent

that H chondrites dominate over L and LL chondrites in our and the Score et al. (1981) suite.

This dominance remains even when taking into

account the pairings discussed above. This is

contrasted by a domination of L over H chondrites and a higher proportion of LL chondrites

among falls (Wasson, 1974) and less so, falls and

finds (Motylewski, 1978) in the rest of the world.

We conclude that among the generally recent

arrivals to the Earth, as represented by observed

falls and finds from the rest of the world, L and

LL chondrites occur in much greater proportion

than among the generally earlier arrivals represented by the Antarctic chondrites.

Summary

Mineralogic and petrographic study of 145

previously undescribed, small meteorites weighing <150 g from the 1977 Allan Hills, Antarctica, collection, indicates that 120 are equilibrated (petrologic types 4 to 6) H(102), L(16),

and LL(2) group chondrites. The remaining

25 specimens include 19 that are paired with

the graphite-magnetite-bearing L3 chondrite

ALHA77011; three unpaired L3 ordinary chondrites; two paired specimens of an enstatite chondrite (EH4); and one carbonaceous chondrite

(C3O). The discovery of new and rare meteorites

that are generally no more severely weathered

than large meteorites strongly argues for continued collection of small meteorites in Antarctica.

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Classification, Metamorphism, and Brecciation

of Type 3 Chondrites from Antarctica

Edward R.D. Scott

Introduction

Japanese and United States expeditions to Antarctica are known to have recovered 60 specimens, which probably represent about 21 different type 3 chondrites. About 59 type 3 chondrites have been recovered from outside Antarctica and over two-thirds of these are poorly described or inaccessible. Thus the Antarctic specimens represent a substantial addition to our

supply of type 3 chondrites—the least metamorphosed or altered samples of early solar system

materials. Interestingly, the ratio of ordinary to

carbonaceous type 3 chondrites (Table 5) is much

higher for Antarctic (4.2) than non-Antarctic

meteorites (2.8) and for meteorite falls (2.1).

Reid (1982) has observed similar disparities between Antarctic and non-Antarctic achondrites

and speculates that the flux of meteorites reaching the earth may have changed with time, as the

Antarctic samples have longer mean terrestrial

ages (Evans et al., 1982).

This paper describes the 21 type 3 chondrites

that have been identified to date among the

1969-1980 collections, and reviews chemical

and petrologic studies relevant to their classification into groups and subtypes. I present new

electron-probe analyses of silicates in 11 type 3

and 4 ordinary chondrites, which suggest that

several should be reclassified. Seven of these

Edward R.D. Scott, Department of Geology and Institute of

Meteoritics, University of New Mexico, Albuquerque, New

Mexico £7131.

chondrites contain both equilibrated and unequilibrated chondrules, indicating that metamorphism must have preceded lithification of

these rocks. I conclude that most type 3 chondrites are probably breccias of materials with

differing metamorphic histories.

TABLE 5.—Approximate numbers of Antarctic and nonAntarctic type 3 chondrites described before 1983.

Class

ORDINARY

H3

L3

LL3

CARBONACEOUS

C3O

C3V

OTHER

Total

Antarctic

5

9

3

2

1

1

21

Non-Antarctic

17

13

11

6

9

3

59

ACKNOWLEDGMENTS.—I thank A. Bischoff,

A.E. Rubin, and C. Williams for technical assistance, K. Keil, S.G. McKinley, D.W. Sears, and

GJ. Taylor for useful advice and data, and the

Antarctic Meteorite Working Group (USA) and

the National Institute of Polar Research (Japan)

for the loan of samples. This work was supported

in part by NASA grant NGL 32-004-064 to K.

Keil.

Techniques

Randomly chosen olivine and low-Ca pyroxene

grains in 11 type 3 and 4 chondrites were ana73
74 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

lyzed in the electron probe for Fe, Mg, Si, and

Ca using crystal spectrometers (Fodor and Keil,

1976). In addition 4 to 10 olivine grains and,

where possible, an equal number of pyroxene

grains were analyzed in each of 109 chondrules

in 8 of these chondrites. Chondrules with heterogeneous silicates were analyzed more thoroughly. These analyses were not made randomly;

cores and rims of grains of various sizes both

near the center and rim of chondrules were

analyzed.

Bulk chemical data for major and minor elements are available for only 7 of the 24 meteorites listed in Table 6. Thus, classifications are

based very largely on abundances of metallic Fe,

Ni and olivine compositions. Dodd et al. (1967)

showed that the most unequilibrated ordinary

chondrites do not have peaks in histograms of

their olivine compositions. However, in cases

where 50% of the analyses lie in a narrow peak,

the olivine composition seems to be as accurate

a guide for classification as it is for types 4 to 6

chondrites. Jarosewich and Dodd (1981) identify

one such chondrite, Carraweena, for which

chemical and mineralogical data suggest different classifications (LL and L, respectively).

Type 3 Carbonaceous Chondrites

Four type 3 carbonaceous chondrites are

known to have been recovered from Allan Hills

(ALH) and Reckling Peak (RKP), Antarctica:

ALHA77003, ALHA77029, ALHA77307, and

RKPA80241. Yamato 6903 is also discussed below as it has been classified as a C3 chondrite

(Okada, 1975), although it is probably a type 4.

Data for these chondrites are summarized with

those for type 3 ordinary chondrites in Table 6.

Classifications, sample weights, and degrees of

weathering are taken from the catalogs of Yanai

(1979), King et al. (1980), and Score, Schwarz,

et al., (1982) and Score, King, et al. (1982),

except where noted. (The terms C3O and C3V

are used instead of CO3 and CV3 at the request

of the volume editors.)

ALHA77003.—This meteorite was described

as an H3 chondrite by King et al. (1980), but

reclassified as a C3 by Rhodes and Fulton (1981)

in accordance with their chemical data. Scott,

Taylor, et al. (1981) classified ALHA77003 as a

C3O chondrite on the basis of petrologic studies

and published chemical data. Ratios of Al/Si,

Mg/Si and Ca/Si from Jarosewich's (1980) analysis are appropriate for a CO chondrite, a classification with which Kallemeyn and Wasson

(1982a) concur. Its olivines vary widely in composition, 2-45 mole% fayalite, with about half

the analyses in the range Fa34 to Fa40. Thus it has

been metamorphosed more than Ornans but less

than Warrenton (Van Schmus, 1969) and is a

type II or III on McSween's (1977) metamorphic

classification. Analyses of the matrix in

ALHA77003 are reported by Ikeda et al. (1981)

and of microchondrules by Rubin et al. (1982).

ALHA77029.—This 1.4 g meteorite is one of

a suite of small samples described by McKinley

and Keil (herein, p. 56). It was classified by Scott,

Taylor, et al. (1981) as a C3O chondrite on the

basis of its mineralogy. Kallemeyn and Wasson

(1982b) analyzed a 72 mg sample by neutron

activation and agreed with its classficiation as a

CO chondrite. Its olivine compositions vary from

0.2 to 63% Fa with no prominent peak in a

histogram of 50 analyses, like those of Ornans

(Van Schmus, 1969). It is a metamorphic type II

on McSween's (1977) scale and is definitely not

paired with any other Antarctic chondrite so far

described.

ALHA77307.—This meteorite was classified

as a C3 chondrite by King et al. (1980). Scott,

Taylor, et al. (1981) likened 77307 to Kainsaz, a

very unmetamorphosed C3O, from petrologic

studies. Biswas et al. (1981) listed 77307 as a

C3V chondrite, as its Cd concentration is typical

of C3V chondrites but 30 times higher than any

C3O (Takahashi et al., 1978). Kallemeyn and

Wasson (1982a) conclude that the bulk chemistry

of 77307 partly resembles that of CM and CO

chondrites, but they classify it as a unique carbonaceous chondrite. Nagahara and Kushiro

(1982) studied the relationships between chondrules, inclusions, and isolated olivines in this
NUMBER 26 75

meteorite. They identified a sequence of aggregates and chondrules that increased in grain size

and attribute their textural changes to heating

below the liquidus. Moore et al. (1981) also analyzed 77307 and identified traces of amino acids.

RKPA8024L—This 0.6 g meteorite is, surprisingly, the only known C3V chondrite from

Antarctica. (ALHA80133 was tentatively classified as a C3V chondrite by Score, Schwarz, et al.

(1982), but is here paired with ALHA77011

(L3); see Table 8.)

Yamato 6903.—Okada (1975) and Okada et

al. (1975) have provided extensive petrologic and

chemical data for this meteorite under the name

"Yamato (c)," and classified it as a type III carbonaceous chondrite. McSween (1979) lists it as

a C3V chondrite, although the published silicate

analyses and textural descriptions suggest it may

be a type 4 or 5 chondrite. Additional evidence

for a higher petrologic grade is provided by

Clayton et al. (1979), who found some equilibration of oxygen isotopes between minerals, like

that in Karoonda, which is a type 5 (McSween,

1979). The bulk Al/Si, Mg/Si, and Ca/Si ratios

TABLE 6.—Type 3 chondrites from Antarctica and their properties (anom. = anomalous; br =

breccia containing more equilibrated clasts or regions; rbr = regolith breccia containing solarwind noble gases and equilibrated clasts).

Name

ALHA76004

ALHA77003

ALHA77011

ALHA77O13

ALHA77029

ALHA77176

ALHA77197

ALHA772151

ALHA77278

ALHA77299

ALHA77304

ALHA773O7

ALHA78084

ALHA79003

ALHA79022

OTTA80301

RKPA79008

RKPA80205

RKPA80207

RKPA80241

RKPA80256

Yamato 6903

Yamato 74191

Yamato 75028

Class

and

type

LL3a

C3Ob

L3C

L 3d

C3Ob

L 3d

L 3d

L3-rbr c

LL3f

H3-br

L4n

C3 anom.

H4n

LL3h

L3-brn

H3

L3

H3

H 3 n

C3V

L3

C4?«n

L3

H3-rbr

Subtype1"

3.3

3.4-3.5

3.5

3.2

3.6

3.8

3.6

3.7

3.7?

3.9

3.4h

3.7?

3.7

3.7

3.7

3.2?

3.6?

3.6

Original

weight

(g)

305a

779.6

6338C

23.0

1.4

54.4

20.3

3046

312.9

260.7

650.4

181.3

14280

5.1

31.4

35.5

73.0

53.8

17.7

0.6

153.2

150

1091.6

6100

Degree

of

weathering

A

A

C

B

d

A/Bd

B

d

A/Bd

B

A

A

B

A

B /C

B

A / B

B /C

B

B

C

B

B

A

n

Olivine composition

Mean

%Fa

1 7 n

25b

17C

19d

23b

12d

24d

24e

22R

l 7 n

25.5n

13b

18.7n

26h

23.6n

18.2"

23n

16n

19n

3

j

23.8"

301

2 1 n

19.4k

a/mean

%

56n

52b

48C

20d

83b

67d

12d

4 4 g

33"

4"

130b

1.7"

4 3h

4

n

6

n

18n

20n

22"

5

n

l

j

23n

' ALHA77216, 77217, and 77252 are paired with ALHA77215.

REFERENCES (for sources of unreferenced data, see p. 73):a Olsen et al., 1978;

 b Scott,Taylor,

et al., 1981; ' McKinley et al., 1981, and Table 8 herein;

 d McKinley and Keil, herein; e Score,

1980; ' McSween and Wilkening, 1980;

 g A. Okada, personal communication; h Scott, Taylor,

Maggiore, 1982; ' Score, Schwarz, et al., 1982;j Okada, 1975, and Okada et al., 1975;

 k Yanai

et al., 1978;'" Sears et al., 1980, 1982, and Sears and Weeks, 1983;

 n this work.
76 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

for Yamato 6903 (Shima and Shima, 1975) are

all in the range of carbonaceous chondrites (Wasson, 1974). Ca/Si and Ca/Mn ratios are consistent with those of CV chondrites (Kallemeyn and

Wasson, 1981), but Al/Si and Al/Mn appear to

be too low. Further studies are obviously needed

to establish its classification.

Type 3 Ordinary Chondrites

Seventeen Antarctic type 3 ordinary chondrites and 2 that are reclassified in this paper

from type 3 to type 4 are listed in Table 6 with

some of their properties. Data for paired specimens are listed under the name of the specimen

with the lowest number (Graham, 1980). Histograms of olivine and low-Ca pyroxene analyses

in 11 of these chondrites are shown in Figures

64 and 65 (less and more metamorphosed chondrites, respectively). Table 7 lists the number of

analyses, mean fayalite and ferrosilite concentrations, and coefficient of variation, which is the

standard deviation of the analyses (mole% fayalite or ferrosilite) expressed as a percentage of the

mean. Also listed for the olivine analyses is the

percent mean deviation (PMD) of the FeO

weight concentrations in olivine. This parameter,

which was first used by Dodd et al. (1967), is not

as convenient as the standard deviation, but it is

listed because Van Schmus and Wood (1967)

used it to define the boundary between type 3

and 4 chondrites; type 3 chondrites have a PMD

that exceeds 5.

For a normal distribution, the mean deviation

is (TT/2)~1/2 or 0.80 times the standard deviation.

Since mole% Fa and wt.% FeO are not linearly

related, this relationship will not hold exactly for

PMD (calculated from wt.% FeO) and CV (from

mole% Fa or Fs), even neglecting deviations from

normal distributions. For eight of the chondrites

in Figures 64 and 65, the PMD/CV ratios for

low-Ca pyroxene analyses are close to 0.80 (0.76

to 0.82), but for olivine analyses, which are generally far from normally distributed, the PMD/

CV ratios average 0.63 ± 0.14.

Of the eight other ordinary chondrites that

are listed in Table 6 but not in Table 7, three

have already been described in some detail:

ALHA77O11 (McKinley et al., 1981), ALHA

77278 (McSween and Wilkening, 1980) and

ALHA79003 (Scott, Taylor, and Maggiore,

1982). Another three are described for the first

time by McKinley and Keil (herein, p. 59). The

other two type 3 ordinary chondrites are regolith

breccias: ALHA77215 and Yamato 75028; they

are the only ones for which thin sections were

TABLE 7.—Electron microprobe analyses of olivines and low-Ca pyroxenes in 11 Antarctic

type 3 and 4 ordinary chondrites (br = breccia; PMD = percent mean deviation calculated

from FeO wt.% (see Dodd et al., 1967)).

Specimen

number,

Section

ALHA76004, 8

ALHA77299, 40

ALHA77304, 35,36

ALHA78084, 135

ALHA79022, 14

OTTA80301, 13

RKPA79008, 7

RKPA80205, 12

RKPA80207, 11

RKPA80256, 17

Yamato 74191, 92

Class

LL3

H3-br

L4

H4

L3-br

H3

L3

H3

H3

L3

L3

Anal.

No.

53

38

29

64

49

28

35

36

36

35

74

Olivine

Mean

% Fa

17.3

17.1

25.5

18.7

23.6

18.2

22.6

16.0

18.7

23.8

21.4

o-/mean

%

56

33

3.6

1.7

4.3

6.1

18.1

19.6

22.1

4.7

23

PMD

40

24

2.1

1.6

2.5

2.5

9.0

10.5

12.8

2.8

17.3

Low-Ca pyroxene

Anal.

No.

39

38

22

71

40

35

35

36

37

35

76

Mean

% Fs

12.1

13.7

16.7

16.7

17.7

11.0

15.5

13.0

15.3

15.6

11.8

<r/mean

%

66

49

38

11.7

29

45

39

32

43

30

59
NUMBER 26

CD

Z5

QCD

u_

30

20

10

40

30

20

10

40

30

20

10

40

30

20

10

80

70

20

10

60

20

10

-

J J m

-

-

-

i —

-

-

-

—m-

-

-

-

—^^•'

_

-

-

OLIVINE LOW-CA PYROXENE

10 20 30 10 20 30

' Allan'HillsA76004 ' (LL3)

JbL J ^ Lk H L LL

• Yamato 74191 (L3)

1 i 1

• Reckling Peak A80207 (H3)

1 j J

MM

•

• ^

— ^

m Allan Hills A77299 (H3-br)

1

1

m Reckling Peak

I

J

A80205 (H3)

' _ Reckling Peak A79008 (L3)

h ] j

10 15 20 25 30 35 0 5 10 15 20 25 30

Fayalite (mole %) Ferrosilite (mole %)

a

-

-

-

-

-

—r

c

-

-

-

—r

d-

-

-

-

—r

e

-

-

f

-

-

30

20

10

40

30

20

10

40

30

20

10

40

30

20

10

20

10

20

10

35

77

FIGURE 64.—Histograms of electron-probe analyses of randomly chosen olivine and low-Ca

pyroxenes in six mildly or moderately metamorphosed type 3 ordinary chondrites from

Antarctica (Table 7). Chondrites are arranged in approximately increasing order of their

proportion of equilibrated olivines. Compositional ranges for equilibrated H, L, and LL groups

are from Gomes and Keil (1980).
78 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

OLIVINE LOW-CA PYROXENE

i i

H L Allan Hills A77304 (L4) H L

 a

Allan Hills A79022 (L3-br)

I Outpost Nunatak A8030I (H3)

Allan Hills A78084 (H4)

10 15 20 25 30 0

Fayalite(mole%)

d

10 15 20 25

Ferrosilite (mole%)

60

40

20

0

60

40

20

0

60

40

20

0

80

40

20

0

60

40

20

0

FIGURE 65.—Histograms of olivine and low-Ca pyroxenes in three well metamorphosed type

3 chondrites and two type 4 chondrites, which were previously classified as type 3 (Table 7).

In all five chondrites, over 90% of the olivines have compositions in the equilibrated H or L

range. However, the proportion of equilibrated low-Ca pyroxenes in each chondrite varies

from 5-70%, and, as in Figure 64, these values are not well correlated with the proportion of

equilibrated olivines. Metamorphism of chondritic components in diverse locations prior to

final lithification accounts for the poor correlations.
NUMBER 26 79

not available during the course of the study. Also

included in Table 6 are ALHA78084 and 77304,

which are here reclassified as type 4 chondrites.

Two ordinary chondrites that have been classified as type 3 chondrites have been omitted

from Table 6. Yamato 74065 and the paired

specimen 74066 were listed as an L3 chondrite

by Yanai (1979) and by Takeda et al. (1979).

The section loaned to us (Yamato 74066,73),

however, is an L5 chondrite, with olivine Fa23.5

to Fa25.5 and low-Ca pyroxene Fsi95 to Fa22.oYanai et al. (1978) found very heterogeneous

olivines and pyroxenes in Yamato 74492, and

Yanai (1979) listed it as an H3 chondrite. However, section 74492,81 is an H6 chondrite with

homogeneous olivine, Fai8.5, and low-Ca pyroxene, Fsie.oIn the brief review below of petrologic and

chemical studies that are relevant to the classification of these chondrites, the original descriptions and analyses by King et al. (1980), Score,

Schwarz, et al. (1982) and Score, King, et al.

(1982) are not referred to unless there are conflicting data. However, these papers are the primary source of petrologic information for many

of the type 3 ordinary chondrites. Possible specimen pairings are discussed below; except where

noted in Tables 6 and 8, it appears that these

samples are not paired, but a few cases deserve

further study.

ALHA76004.—The first type 3 chondrite to

be recovered from Antarctica is one of the least

TABLE 8.—List of specimens paired with ALHA77011, L3

chondrite (* = small samples; see Table 3 herein).

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*

78038

78188

79001

79045

80133

equilibrated. Figure 64a shows that its olivines

are more heterogeneous than any of the other

10 chondrites analyzed. Like ALHA77176, the

other very primitive ordinary chondrite, it contains abundant opaque matrix (Huss et al., 1981),

which was analyzed by Ikeda et al. (1981). Detailed petrologic descriptions of ALHA76004

are provided by Olsen et al. (1978), who classified

it as an LL3, and Ikeda (1980). Although the

oxygen isotopic composition of clasts in

ALHA76004 are more extreme than those reported for components in other ordinary chondrites (Mayeda et al., 1980), this chondrite may

not be more unusual than other primitive chondrites, such as Bishunpur and Semarkona.

ALHA77011.—This meteorite and the paired

specimens (Table 8) all contain a few volume

percent of graphite-magnetite aggregates (McKinley et al., 1981). These samples are paired

with some confidence because other type 3 chondrites contain much less graphite-magnetite, except for Sharps, which has 11 vol.%. However,

Sears et al. (1982) believe that the samples may

represent two falls, as their thermoluminescence

sensitivity values vary by a factor of 3. Extensive

sampling of a large type 3 chondrite would be

useful to help establish what variation in chemical

and physical properties can be expected in a

single meteorite.

Chondrules in ALHA77011 (Nagahara,

1981a, 1981b; Fujimaki et al., 1981; data on

specimen ALHA77015) do not seem to be different from those in other ordinary chondrites.

Ikeda et al. (1981) argue that the opaque matrix

in three ALHA77O11 specimens is different in

composition from matrices in three other ordinary type 3 chondrites. Chiefly on the basis of

the Na/Al ratio, they find that the matrix of

77011 resembles matrices in C2 and C3 chondrites. However, Na/Al matrix ratios in Sharps

and Krymka (Huss et al., 1981) are nearly as low

as that of 77011. The bulk composition of this

meteorite (Jarosewich, 1980; Rhodes and Fulton,

1981) appears to be typical for L chondrites

(McKinley et al., 1981).

ALHA77215.—This is only the sixth L chon-
80 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

drite known to contain solar-wind gases (Goswami, 1981). It and the three paired specimens

(Table 6) contain 47 vol.% of mineral, lithic, and

chondrule fragments (Score, 1980), and solarflare tracks (Nautiyal et al., 1982). Like many

other chondrite regolith breccias, this meteorite

also contains graphite-magnetite aggregates

(Scott, Rubin, et al., 1981).

ALHA77278.—Although 77278 is very rich

in In and Tl (Biswas et al., 1980), McSween and

Wilkening (1980) found that its olivine is not as

unequilibrated as might be expected. ALHA

76004, for example, has olivines that are more

heterogeneous (Figure 64«) although its In and

Tl concentrations (Biswas et al., 1981) are lower.

McSween and Wilkening (1980) and King et al.

(1980) classify ALHA77278 as an LL chondrite

on the basis of Co concentrations in kamacite

and a bulk chemical analysis by Jarosewich

(1980). Jarosewich and Dodd (1981) concur with

this classification.

This meteorite is only one of four ordinary

chondrites (all LL) known to contain carbides

and magnetite (Taylor et al., 1981; Scott, Taylor,

and Maggiore, 1982). Equilibrated chondrules,

but not clasts, were identified by Scott, Taylor,

Keil, (1982), and a carbonaceous clast was tentatively identified by King et al. (1980). Weber

et al. (1983) found significant excess

 4He in

ALHA77278, indicative of solar-wind gases.

However, its Ne isotopic ratios marginally fail

the suggested requirements of Wasson (1974) for

a solar-gas-rich meteorite.

ALHA77299.—The mean composition of olivine (Figure 64d) and the abundance of metallic

Fe,Ni enabled King et al. (1980) to classify 77299

as an H3 chondrite. Analyses by Jarosewich

(1980), Rhodes and Fulton (1981), and Biswas et

al. (1980) confirm this classification. Additional

petrologic descriptions are provided by Haggerty

et al. (1979) and Ikeda etal. (1981). An H4 clast

is described in the section on breccia properties.

ALHA77304.—This meteorite was classified

by King et al. (1980) as an LL3 chondrite, but

the data in Table 7 and Figure 65« indicate that

it should be classified as L4 because of its homogeneous olivine; PMD is 2.1, mostly Fa25 to

Fa26. Although King et al. (1980) found more

heterogeneous olivine (Fai8 to Fa27), B. Mason

and H. Nagahara (private communications) confirm the L4 classification of ALHA77304. King

et al. (1980) note that clasts up to 1 cm in

diameter are visible on the surface of this chondrite.

ALHA78084.—This 14 kg meteorite was initially classified as an H3 chondrite (Score, King,

et al., 1982), but the homogeneity of its olivine

in Figure 65e (PMD of olivine is 1.6) is more

appropriate to type 4 (Van Schmus and Wood,

1967). Extensive weathering probably made the

interchondrule material more opaque, and the

chondrules more prominent than normal for a

type 4 chondrite. The opaque matrix typical of

type 3.0-3.6 ordinary chondrites (Huss et al.,

1981) is absent.

ALHA79003.—This tiny meteorite was

paired with ALHA79001 by Score, King, et al.

(1982) but unpaired by Scott, Taylor, and Maggiore (1982). The latter authors identified 79001

as a specimen of ALHA77011, and reclassified

79003 as the third Antarctic LL3 chondrite. As

with non-Antarctic type 3 ordinary chondrites,

these three LL3 chondrites are less equilibrated

than most Antarctic H3 and L3 chondrites.

ALHA79022.—Score et al. (1981) found heterogeneous olivines with Faj to Fa28 and classified this meteorite as an H3, but Figure 656

shows that some areas have very homogeneous

olivine typical of L4 chondrites (very largely Fa23

to Fa25). On the assumption that the more heterogeneous areas represent matrix and that the

meteorite does not contain a mixture of H and

L material, 79022 is classed as an L3 breccia in

Table 6. Limited published data on ALHA77215

are similar to those of this meteorite, suggesting

that the possibility of pairing needs more study.

ALHA77304, which is another L3-4 breccia,

has olivines with significantly higher FeO concentrations (Figure 65a) than 79022. However, comparing heterogeneous breccias is clearly a difficult task.

OTTA80301.—Score, Schwarz, et al. (1982)
NUMBER 26 81

tentatively classified this meteorite from Outpost

Nunatak as an H3 chondrite, and this classification is retained here, even though its olivine

composition in Table 7 (PMD of olivine equals

2.5) is too uniform for a type 3. All but two of

28 olivine analyses in Figure 65d lie in the range

Fai8.2 to Fai8.9, entirely appropriate for H4 chondrites. However, if one more olivine grain had

been encountered that was a little richer in forsterite than the most Mg-rich olivine actually

analyzed (Fai3), then the PMD of olivine could

have exceeded 5, the upper limit for type 4

chondrites. Thus it may be very difficult to apply

this criterion with confidence to distinguish type

3 and 4 chondrites without many hundreds of

analyses over a large surface area.

RKPA79008.—Silicate analyses in Figure

64/ are entirely consistent with those of Score,

King, et al. (1982) and their classification of RKPA

79008 as an L3. Olivine compositions in

RKPA80256, which is also a moderately equilibrated L3, are slightly more fayalitic (mostly Fa22

to Fa24). Although the variation to be expected

in a single meteorite is not well known, it seems

best to assume that these specimens are not

paired.

RKPA80205.—Olivine analyses in Figure 64^

are consistent with the tentative classification of

80205 as an H3 (Score, Schwarz, et al., 1982).

RKPA80207 is an H3 chondrite with similar

silicate heterogeneity, which was presumably

found in the vicinity of 80205. However, it can

be distinguished from 80205 as its olivine is

richer in fayalite (Figure 64c, e), assuming that

the sections analyzed are representative of the

whole specimens. Thermoluminescence sensitivity results of Sears and Weeks (1983) on the two

specimens are also significantly different, although their result for 80207 is not consistent

with the silicate analyses in Table 7.

RKPA80207.—The low concentration of metallic Fe,Ni in this chondrite indicated to Score,

Schwarz, et al. (1982) that it is an L chondrite.

However, the position of the prominent peak in

the histogram of olivine analyses (Fai6 to Fa2o,

Figure 64c) strongly suggests that it is an H

chondrite, especially as severe weathering of this

specimen hinders accurate estimates of its metal

abundance.

RKPA80256.—Silicate analyses in Figure 65c

confirm the tentative classification of this meteorite as an L chondrite (Score, Scharz, et al.,

1982). However, the olivine PMD of 2.8 (Table

7) is too low for a type 3. Because of the difficulty

of measuring PMD accurately (p. 76), the type 3

classification of Score, Schwarz, et al., is retained.

Yamato 74191.—This chondrite is one of the

least equilibrated type 3 chondrites from Antarctica (Figure 64b). Detailed studies of its chondrules and abundant translucent matrix are provided by Kimura et al. (1979), Ikeda and Takeda

(1979), and Ikeda et al. (1981).

Yamato 75028.—This H3 chondrite contains

solar-wind gases (Takaoka et al., 1981) and is

only the second chondrite regolith breccia found

in Antarctica. Petrologic descriptions of the H3

matrix and more equilibrated clasts are given by

Takeda et al. (1979), Ohta and Takeda (1982),

and Miyamoto et al. (1982).

Petrologic Subtypes

Type 3 ordinary chondrites have recently been

subdivided according to the degree of metamorphism that they have experienced (Sears et

al., 1980; Huss et al., 1981). The decimal subdivision into types 3.0 to 3.9, which was proposed

by Sears and coworkers, has been adopted by

most people and is based on measurements of

thermoluminescence sensitivity. This parameter

appears to be the most useful for classifying type

3 ordinary chondrites. Sears et al. (1980, 1982)

have shown that many properties of these chondrites are so well correlated that chondrites can

be classified into subtypes by other parameters if

thermoluminescence data are not available. The

subtypes, listed in Table 6 for 18 chondrites are

from Sears et al. (1982) and Sears and Weeks

(1983), except for ALHA79003, for which thermoluminescence data are not available. Sears and

coworkers claim that thermoluminescence data

permit subtype classification to a 1 a uncertainty
82 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

s

*=60

50

O40

8

*=30

O 20-

10-

o

A77I76

A76004

t 1 i t i

A79003

X H

oL

• LL

A77278

A77299

3207

° ! O Y74I9I "i

A7701 3

 R790O8O

O i A77I97

R80205

R80256 x08030 | |

° OA79022 A78O84T

QA773O4 E

3.0 3.2 3.4 3.6

Petroloqic type

3.8

FIGURE 66.—Plot of coefficient of variation of olivine compositions (aFa/mean Fa) from Table 6 against petrologic

subtype from Sears et al. (1982) and Sears and Weeks (1983)

for 17 Antarctic type 3 and 4 ordinary chondrites. With

the exception of RKPA80207 and RKPA80256, and

ALHA79022 and ALHA77304, olivine coefficients are

close to the ranges shown for the subtypes (Sears, et al.,

1982). These four chondrites have much more homogeneous olivine than would be predicted from the thermoluminescence sensitivity data of Sears and coworkers. The dashed

line for RKPA79008 is an estimate of the ±2<r error in its

coefficient of variation.

1.0-

0.61-

O

8 0.4

%

O 0.2-

1—

-

. 1

-

-

-

I

,

— 1 —

I

—1 1 1

OA770II

I _

I :

A77278

• • •

- i 1 1

X

o

•

TA77299

•

H

L

LL

I

A772I5 A78084

A77304 o

0 ;

A

3.0 3.2 34 3.6

Petrologic type

3.8

FIGURE 67.—Plot of bulk carbon concentration against subtype for six type 3 ordinary chondrites. The limited C data

from Jarosewich (1980), Gibson and Andrawes (1980), and

Grady et al. (1982) scatter widely from the ranges predicted

by Sears et al. (1980). The dashed line shows the range of C

concentrations in ALHA77299 obtained by these authors.

f

(J

00

100

1°

o

o

o

o

A770II

A76004"

H

L

LL

TA77278 X

A77304

° ^A772I5

1

3.0 3.2 3.4 3.6

Petrologic type

3.8

FIGURE 68.—Primordial

 36Ar concentrations in Antarctic

type 3 ordinary chondrites decrease with increasing subtype

and are close to the subtype ranges in Sears et al. (1980).

Noble gas analyses are by Weber and Schultz (1980), Takaoka et al. (1981), Nautiyal et al. (1982), Kaneoka (1980),

Moniot et al. (1981), and Weber et al. (1983).

0.2

0.15

§ 0.

|

O0.05

o

O

^77176

Sem

R80207:;

R80256

A79O22J

3.0 3.2 3.4 3.6

Petrologic type

3.8 4-6

FIGURE 69.—Mean CaO concentrations of randomly chosen

olivine grains are inversely correlated with subtype in type

3 ordinary chondrites. Data from Noonan et al. (1977) for

St. Mary's Co. (StM); S.G. McKinley (private communication) for ALHA77011, ALHA77013, ALHA77176, and

ALHA77197; remainder including Semarkona (Sem), this

work. Vertical bars for individual meteorites are ±2a of

mean values; ranges of types 4-6 from Busche (1975).
NUMBER 26 83

of ±0.1, except in cases of extensive weathering,

which may lower the thermoluminescence sensitivity and the subtype. Shock may also affect the

thermoluminescence sensitivity (Sears, 1980).

Figures 66-68 show data for Antarctic type 3

ordinary chondrites, illustrating the inverse correlations of petrologic subtype with coefficient

of variation of olivine (<rFa/mean Fa) and the

concentration of C and primordial

 36Ar. Also

marked are the ranges expected within subtypes

from Sears et al. (1980, 1982). Unfortunately,

bulk C and Ar concentrations have only been

measured in about one-third of the Antarctic

type 3 ordinary chondrites. However, in general,

assignments based on olivine heterogeneity and

C and

 36Arp concentrations are within 0.2 of the

subtype derived from thermoluminescence sensitivity data.

Dbdd (1969, 1981) finds that CaO concentrations in olivine vary according to petrologic type

in ordinary chondrites: type 3 olivines have ^0.1

wt.% CaO, type 4 have 0.06 wt.%, and type 5-6

0.02-0.05 wt.% CaO. Figure 69 shows that even

though CaO concentrations in olivine may vary

widely within a single type 3 chondrite, the mean

value can also be used to classify type 3 chondrites according to subtype with an accuracy

better than ±0.2. Chondrites that do not lie on

the trends in Figures 66-69 are discussed below.

RKPA80207.—The subtype of 3.2 assigned

by Sears and Weeks (1983) is not consistent with

the degree of homogeneity of its olivine (Figure

66) and low-Ca pyroxene, which both have peaks

in the H range (Figure 64c), and its low CaO

concentration in olivine (Figure 69). These parameters and the absence of fine-grained, FeOrich, opaque silicate matrix, or "Huss matrix"

(Huss et al., 1981) indicate that type ~3.6 might

be a better classification.

ALHA77O11.—This L3 chondrite has higher

concentrations of C and

 36Arp than expected for

its subtype of 3.4-3.5 (McKinley et al., 1981;

Sears et al., 1982). Excess C can be attributed to

abundant graphite-magnetite.

ALHA79022, ALHA77304 and RKPA

80256.—These three L chondrites have olivines

that are too homogeneous and low in CaO to be

consistent with their thermoluminescence data.

The latter suggest type 3.6 to 3.7 (Sears and

Weeks, 1983), whereas olivine compositions suggest type 3.9 or 4.

Although the boundary between types 3 and

4 chondrites is quantitatively defined by Van

Schmus and Wood (1967) in terms of olivine

heterogeneity (PMD of wt.% Fe is 5), in practice,

the distinction is difficult to make. As discussed

in the description of OTTA80301, the presence

of a few percent of very heterogeneous olivines

in a chondrite that contains largely homogeneous

olivine can drastically affect the PMD. Thus

hundreds of analyses on several sections would

be needed to establish the PMD with any confidence. Unfortunately, the thermoluminescence

senstivities of type 4 chondrites are largely indistinguishable from type 3.8-3.9 chondrites (Sears

et al., 1980). It appears that the boundary between type 3 and 4 chondrites must remain indistinct, like the boundary between type 4 and 5

chondrites.

Another difficulty with the classification

scheme of Van Schmus and Wood (1967) concerns the classification of breccias. Regolith breccias, such as Dimmitt (Rubin et al., 1983) and

ALHA77215, are defined as type 3 chondrites

because their matrices have small amounts of

heterogeneous silicates. It seems worthwhile to

distinguish breccias, regolith and otherwise, in

classification schemes by adding suffixes like

those in Table 6.

Some of the above problems in classifying type

3 chondrites according to their subtype may be

due to heterogeneities and the presence of equilibrated clasts. Such clasts have been identified in

the regolith breccias, ALHA77215 (Score, 1980)

and Yamato 75028 (Ohta and Takeda, 1982).

During the course of this study of type 3 chondrite thin sections, only one equilibrated clast

was identified, an H4 clast in ALHA77299 (Figure 70). However, this clast was found accidentally as a result of random probe analyses of its

silicates, and was not prominent in the thin section. King et al. (1980), Score, Schwarz, et al.

(1982), and Score, King, et al. (1982) mention

clasts in their descriptions of many of the type 3
84 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

I mm

FIGURE 70.—Thin section of ALHA77299 (H3). Line marks approximate boundary between

H4 clast on left and H3.7 matrix on right. Clast contains olivine with Fais.4±o.2 (l<r of analyses)

and 0.03 wt.% CaO, and low-Ca pyroxene with Fs16.i±o.4. The matrix contains some chondrules

like those in the clast, some with equilibrated olivine and unequilibrated low-Ca pyroxene, and

others with unequilibrated olivines and pyroxenes (see Figure 7l«).

chondrites, e.g., inclusions of various colors up

to 7 mm in size are present on the surface of

ALHA79022. Unfortunately, it is not known

whether these are chondritic clasts; some might

be large irregular chondrules.

Brecciation and Metamorphism

Dodd et al. (1967) and Dodd (1969) argue

convincingly that mineralogic differences among

type 3 chondrites are the result of metamorphism. Olivine homogeneity is correlated with the

degree of integration of chondrules and matrix,

and the glass abundance in chondrules. Similarly,

Huss et al. (1981) find that olivine homogeneity

is also correlated with the proportion of opaque

matrix and its Fe/(Fe+Mg) ratio. They also attribute most of these mineralogic variations in

type 3 chondrites to mild metamorphism of the

whole rocks.

By contrast, Dodd (1971, 1974) found in

Sharps (H3.4) and Hallingeberg (L-3.3) a significant proportion of chondrules with mineralogic features that he attributes to metamorphism

before the rocks were lithified. These chondrules
NUMBER 26 85

are relatively homogeneous in composition, have

lower CaO concentrations in olivines, and are

commonly zoned with rimward increases in FeO

concentration in olivine, with or without concurrent decreases in CaO.

Scott, Taylor, and Keil (1982) studied three

moderately metamorphosed type 3 ordinary

chondrites, Ngawi (LL3.6), ALHA77278

(LL3.6), and Bremervorde (H3.7), and found in

each a significant proportion of chondrules with

olivine homogeneity and CaO concentrations appropriate to type 4 chondrites. Because metallic

Fe,Ni grains in these three chondrites had cooled

at very diverse rates, they argue that chondrules

and metal grains were metamorphosed at various

depths inside the parent bodies before the three

chondrites were lithified.

To check whether any other Antarctic type 3

chondrites are breccias of unequilibrated and

equilibrated material, olivine and low-Ca pyroxene grains were analyzed in over 100 chondrules

in six chondrites. Figures 71 and 72 show the

mean and la ranges of analyses for CaO and

fayalite concentrations in 4-10 olivine grains in

each chondrule. Yamato 74191 (L3.6), ALHA

77299 (H3.7), RKPA80205 (H3.7) and RKPA

79008 (L3.7) all contain a significant proportion

of chondrules that have olivine and low-Ca pyroxene compositions like those in type 4 chondrites (Figure 71). Unequilibrated chondrules

have olivines with fayalite ranges and mean CaO

concentrations that are generally 5-20 and 2-6

times larger, respectively, than olivines in equilibrated chondrules.

In two of these chondrites, ALHA77299 and

RKPA79008, the presence or absence of chondrule rims composed of opaque Huss matrix

(Huss et al., 1981) is related to olivine heterogeneity in the chondrules. Most of the unequilibrated chondrules and none of the equilibrated

chondrules in these two chondrites have partial

rims of opaque Huss matrix (Figure 7la, b). In

Yamato 74191 and RKPA80205, none of the

analyzed chondrules have rims of opaque matrix.

Yamato 74191 has abundant matrix, but it is all

translucent and in parts recrystallized, and it is

often difficult to decide which chondrule, if any,

is rimmed where matrix material separates adjacent chondrules.

Figure 72« shows analyses of olivine in 15

chondrules from ALHA76004 (LL3.3). None of

the chondrules have mean olivine compositions

appropriate to equilibrated LL chondrites (Fa27.5

to Fa30.5)- All are heterogeneous and have mean

CaO concentrations of 0.05-0.3 wt.%, like the

unequilibrated chondrules in Figure 71. By contrast, Figure 12b shows analyses for 16 chondrules in RKPA80256, which has more equilibrated olivines (Figure 65c) than the chondrites

described above. Only two chondrules have

mean olivine compositions outside the L4-6

range. For comparison, analyses of chondrules

in Richardton (H5) and Bjurbole (L4) are shown

in Figure 72c. Richardton chondrules contain

olivine that is more homogeneous and has lower

CaO concentrations than Bjurbole chondrules.

Both sets of chondrules are more equilibrated

than those in RKPA80256.

It might be argued that olivine in some of the

chondrules plotted in Figure 71 preserved its

heterogeneity and high CaO concentrations

from in situ equilibration with the matrix or other

chondrules because of large crystal or chondrule

sizes. However, the unequilibrated chondrules

are not on average larger or coarser grained than

the equilibrated chondrules. Figure 73 shows

photomicrographs of unequilibrated and equilibrated porphyritic-olivine chondrules in each of

the three chondrites shown in Figure 71. In two

cases the equilibrated chondrule is larger and has

larger olivine phenocrysts than the unequilibrated chondrule. In the other case (Figure 73a,

b), chondrule and phenocryst sizes are very similar.

Another possible barrier to equilibration between olivines is the presence of silicates or other

phases that have low diffusion rates for Fe and

Mg. For example, olivines poikilitically enclosed

by low-Ca pyroxene might be expected to lag

behind other olivines during metamorphic equilibration. However, none of the analyzed olivines

in the unequilibrated chondrules plotted in Figures 71 and 72 are poikilitically enclosed by

pyroxene or any other mineral. There do not
86 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

0.29

0.05

Allan Hills A77299

chondrules

o rimmed by opaque matrix

x opaque matrix rim absent

• equilibrated clast

EQUILIBRATED

-CHONDRULES

K) 20

Fayalite (mole%)

0.3

0.2

0.15

0.05

Yamato 74191

chondrules

15 20

Fayalite {mole %)

0.3

0.25

P 0.2

O

o 0.15

0.1

0.05

n

Reckling Peak A79008

 b

, chondrules

o rimmed by opaque matrix

x no opaque matrix rim

•

1

 <

•

•

•

•

Tu1 • 1 i ,J

1

-

p

* I EQUILIBRATED

J—.^CHONDRULES •

I

0.3

0.25

0.2

O

0.15

O.I

0.05

15 20

Fayalite (mole%)

25

Reckling Peak A80205

chondrules

EQUILIBRATED

-CHONDRULES

10 15 20

Fayalite (mole%)

25 30

FIGURE 71.—Plots of mean CaO concentration in olivine against mean fayalite concentration

for 75 porphyritic-olivine and porphyritic-olivine-pyroxene chondrules in four Antarctic type

3 ordinary chondrites. Bars show ±l a values for 4-10 analyses in each chondrule; \a values

that are not plotted are comparable to the smallest shown. In all four chondrites there are

unequilibrated chondrules containing olivine with variable Fa and CaO concentrations and

>0.05% CaO, and chondrules with uniform Fa and CaO concentrations and <0.05% CaO in

olivine. Chondrules were metamorphosed to different extents before final lithification into

chondrites. The boxes showing the compositions of equilibrated chondrules are defined by

ranges in type 4-6 H and L chondrites (Gomes and Keil, 1980; Busche, 1975).

appear to be any systematic differences in the

mineral textures of unequilibrated and equilibrated chondrules except perhaps in their mesostases, which are generally, but not always,

more crystalline in the latter.

The most plausible explanation for the juxtaposition of equilibrated and unequilibrated chondrules in many of the Antarctic type 3.6 to 4

chondrites is that equilibrated chondrules were

metamorphosed prior to lithification of the chon-
NUMBER 26 87

0.3

0.25

0.2

0.15

0.1

0.05

Allan Hills A76004

chondrules

10 15 20

Fayalite (mole %)

30

0.08

0.07

0.06

— 0.04

D

° 0.03

0.02-

0.01

Richardton (H5)

chondrules

Bjurbdle(L4)

chondrules

C

"

EQUILIBRATED

CHONDRULES

L_s

16 20 22 24

Fayalite (mole %)

0.08

^ 0.06

p

O 0.04

o

o

0.02

Reckling Peak A80256

chondrules

b.

—1

t _

' H

T T

1T

1

X

x

 x

> EQUILIBRATED

CHONDRULES

20 22 24 26 28 30

Fayalite (mole%)

FIGURE 72.—Plots of mean CaO concentration in olivine

against mean fayalite concentration: a, 15 chondrules in

ALHA76004 (LL3.3); b, 16 chondrules in RKPA80256

(L3.6); r, 9 chondrules in Richardton (H5) and 10 in Bjurbole (L4). Unlike the chondrites in Figure 71, ALHA76004

contains no equilibrated chondrules, whereas in

RKPA80256 chondrules are nearly all equilibrated with

mean analyses plotting within the box defined by mean

olivine compositions in L4-6 chondrites. The ranges of CaO

and Fa concentrations in olivine and the CaO concentration

itself within and among chondrules decrease from type 3 to

type 5 chondrites. Most type 3 chondrites, including

RKPA80256, appear to be mixtures of type 3 and 4 chondrites. (The upper limit of Fa concentrations in L4-6 chondrites from Gomes and Keil (1980) should be extended

slightly to include the Bjurbole data).

drites. These chondrites are, therefore, breccias

composed of materials metamorphosed in diverse locations. The argument is strongest for

the chondrites shown in Figure 71. But even for

RKPA80256 (Figure 12b), it seems probable that

some or all of the equilibration between chondrules and matrix occurred before compaction

of the chondrite. The two chondrules plotting

outside the equilibrated chondrule box in Figure

12b are smaller and have smaller grain sizes than

many of the equilibrated chondrules. Thus,

much of the material in this chondrite may have

been metamorphosed to type 4 levels prior to

final lithification. However, metamorphism to

type 3.6-3.8 levels after compaction cannot be

excluded.

Chondrules in RKPA80207 and OTTA

80301, in which olivines are largely equilibrated

(Figures 64c, 65d), were not analyzed in such

detail. However, in each chondrite a porphyriticolivine chondrule with heterogeneous olivine

(Fa 13 to Fa 19 and Fa 12 to Fa 15, respectively) with

appreciable CaO concentrations (0.03-0.21

wt.%) was discovered. Since these chondrules are

not especially large or coarse-grained, it is concluded that these two chondrites are also breccias

of previously metamorphosed materials.

Figure 64 shows that the proportion of equilibrated chondrules in each of the four chondrites

shown in Figure 71 varies considerably. Furthermore, the nature of the equilibrated chondrules in these four chondrites also varies. In
88 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

FIGURE 73.—Photomicrographs of six porphyritic-olivine chondrules in type 3.7 ordinary

chondrites in transmitted light: a and b, ALHA77299; c and d, RKPA79008; e and /,

RKPA80205. Olivine in the three chondrules on the left is heterogeneous (a, Faio to Fa2o; c,

Fa4 to Fai.5; e, Faio to Fai4) and contains high CaO concentrations (0.03-0.31 wt.% CaO),

whereas olivine in the three chondrules on the right is more homogeneous (Fa]8 to Fa2o in b

and/, Fa23 in d) with low CaO concentrations (0.01-0.06 wt.%). Data for these and other

chondrules are plotted in Figure 71. Some of the unequilibrated chondrules like c have rims of

fine-grained, FeO-rich, silicate material ("Huss matrix"), but none of the equilibrated chondrules have such rims. These chondrites and many other type 3 ordinary chondrites are breccias

of materials with diverse metamorphic histories.
NUMBER 26 89

ALHA77299, many of the equilibrated chondrules have low-Ca pyroxene with compositions

appropriate to H4-6 chondrites (Fsi6 to Fai8).

Their presence accounts for the peak at Fsi6 to

Fsi8 in the histogram of randomly chosen pyroxene grains (Figure 64d). For Yamato 74191,

however, the low-Ca pyroxene histogram shows

no such peak in the equilibrated L range (Fsi9 to

Fs23), and the equilibrated chondrules lack pyroxenes with this composition. In fact, equilibrated chondrules in ALHA77299 seem to be

more equilibrated than those in some types 3 and

4 chondrites shown in Figure 65, which overall

have much more homogeneous olivines.

ALHA77304 and RKPA80256, for example,

lack equilibrated low-Ca pyroxenes even though

their olivines, in general, appear to be more

equilibrated than those of ALHA77299. Thus,

various degrees of mixing between materials that

have been metamorphosed to various extents can

account for the strange lack of coherence between the compositions of olivine and low-Ca

pyroxene in the histograms shown in Figures 64

and 65.

Virtually all of the type 3 ordinary chondrites

in which mineral compositions have been studied

in individual chondrules appear to contain chondrules with diverse metamorphic histories. These

include Sharps and Hallingeberg (Dodd, 1971,

1974), Mezo-Madaras (Van Schmus, 1967),

Ngawi, ALHA77278, and Bremervorde studied

by Scott, Taylor, and Keil (1982) and the seven

Allan Hills chondrites discussed above. Van

Schmus (1969) argues that components in C3O

chondrites also experienced metamorphism

prior to compaction of the meteorites. If all type

3 chondrites are mixtures of material with different metamorphic histories, why can they be

considered to a good approximation as a sequence of rocks that were metamorphosed to

various degrees after lithification? Why are their

chemical and textural properties that are controlled by metamorphism so well correlated?

Presumably, the answer to these questions is

that, in general, the materials mixed do not have

very diverse metamorphic histories. Ngawi seems

to have the most extreme components; unequilibrated chondrules rimmed with abundant

opaque matrix and equilibrated chondrules with

homogenous olivine and low-Ca pyroxene (Scott,

Taylor, and Keil, 1982). However, in other type

3 chondrites, the range of metamorphic histories

represented is much smaller, or else the proportion of material with an unusual thermal history

is very small. Brecciation does explain why the

properties of type 3 ordinary and carbonaceous

chondrites are not better correlated. Ngawi, for

example, would be classified as a type 3.3 from

the composition of its opaque matrix, but type

3.7 from its bulk C concentration (Sears et al.,

1982). Some "measures of metamorphism" are

controlled solely by the properties of the least

unequilibrated chondrules, whereas others are

controlled more by the proportion or nature of

the most equilibrated chondrules. Bulk thermoluminescence sensitivity, which varies by a factor

of 104 in type 3 chondrites, is very sensitive to

the amount of equilibrated (type 4) material.

Variable degrees of metamorphism may be responsible for some of the spread in the TL sensitivities of individual chondrules in Dhajala

found by Sparks et al. (1983).

Some of the results in this paper might be used

to argue against the thesis that metamorphism

caused equilibration and recrystallization. Kurat

(1969) and Fredriksson et al. (1975) suggest that

uniform olivine and pyroxene compositions are

a result of crystallization, and not metamorphism. However, like Dodd et al. (1967), Huss et

al. (1981), and most other workers, I believe that

all ordinary chondrites were formed by metamorphism (and brecciation) of materials very

similar to the most primitive type 3 ordinary

chondrites. Although Fredriksson, Kurat, and

coworkers are correct in arguing that constant

olivine compositions were not established in situ

in these breccias, there is very strong evidence

that metamorphism in precursor rocks was responsible (Dodd, 1969). Type 3 chondrites contain suites of chondrules that have virtually identical textures (except in their mesostases and

rims) but vary widely in silicate heterogeneity.

Chondrules may contain heterogeneous olivine

and low-Ca pyroxene, homogeneous olivine and
90 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

heterogeneous pyroxene or olivine and low-Ca

pyroxene that are entirely homogenous. This is

consistent with the much higher cation diffusion

rates in olivine compared to those in pyroxene;

Jones (1983) estimates that olivine diffusion rates

are 103 times higher.

The presence of some proportion of equilibrated chondrules in many type 3.5-4 chondrites

means that it is possible to classify chondrites on

the basis of the olivine composition in these chondrules, even when much of the olivine is heterogeneous. Although Dodd (1968) believed he had

identified three equilibrated LL chondrules in

the H chondrite, Sharps, no such aberrant chondrules were encountered in this study. Mixing of

material from different ordinary chondrite

groups seems to be very limited, even on parentbody surfaces (Keil, 1982; Rubin et al., 1983).

Of the seven Antarctic type 3 chondrites that

have been identified above as breccias, only one,

ALHA77299, is known to contain chondritic

clasts. Brecciation in type 4-6 chondrites is easier

to identify than in type 3 chondrites as more

metamorphosed materials are generally better

lithified and thus form clasts rather than chondrules when broken. 'Metamorphosed' chondrites that contain a small fraction of minerals

with aberrant compositions or textures, e.g.,

Bhola (Noonan et al., 1978) and Pulsora (Frederiksson et al., 1975), are generally recognizable

as breccias of previously metamorphosed material. However, all others, e.g., Morro do Rocio

(Wlotzka and Fredriksson, 1980), must be breccias also, unless the aberrant minerals have been

isolated from diffusive equilibration by barriers

such as large grain size.

Summary

Four carbonaceous type 3 chondrites from

Antarctica are known: one C3V, RKPA80241;

two C3O, ALHA77003 and 77029, and a unique

C3, ALHA77307. Yamato 6903 may be a C4V.

ALHA80133 is an L3 chondrite paired with

ALHA77011,notaC3V.

Seventeen different ordinary type 3 chondrites

from Antarctica are recognized. ALHA77304 is

reclassified from LL3 to L4, ALHA78084 from

H3 to H4, and RPKA80207 from L3 to H3.

Analyses of sections of ALHA79022, OTTA

80301, and RPKA80256 suggest that they are

type 4 meteorites, but because of the difficulty

of determining PMD olivine when a small percentage of chondrules are heterogeneous, they

have not been reclassified from type 3 to

type 4. ALHA77299 (H3) contains an H4

clast but is not rich in solar-wind noble gases

(Weber et al., 1983). Two type 3 chondrites are

regolith breccias, ALHA77215 and Yamato

75028.

In general, silicate analyses are consistent with

the subtype classification from thermoluminescence sensitivity data by Sears and coworkers.

However, RKPA80207 appears to be a type

-3.6 not a 3.2. ALHA79022, ALHA77304 and

RKPA80256 have olivine compositions indicative of type 3.9 or 4, rather than 3.6 to 3.7, as

Sears and Weeks (1983) suggest.

The mean concentration of CaO in olivine is

another parameter like olivine heterogeneity

that is inversely correlated with subtype, decreasing from 0.15 to 0.2 wt.% for type 3.0-3.3 to

=£0.05 wt.% for type 3.7-4.

Seven type 3.5-4 ordinary chondrites contain

equilibrated chondrules with CaO and FeO concentrations in their olivines like those of type 4

chondrites, even though some of their chondrules have heterogeneous olivines like those in

type 3.0-3.5 chondrites. Metamorphic equilibration must have occurred before lithification of

the chondrites. Probably all type 3 chondrites

are breccias composed of chondrules with diverse

metamorphic histories.

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94 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

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8:110-120.
A Meteorite from the Moon

Ursula B. Marvin

On 18 January 1982, John Schutt spotted a

small meteorite with a frothy greenish tan fusion

crust lying near the edge of the Middle Western

Icefield of the Allan Hills region (Figure 74).

Large white clasts lying in a dark matrix were

clearly visible beneath patches of crust and on a

broken surface. After two seasons of collecting

Antarctic meteorites, Schutt, who had led the

United States search party for the first half of

that season, immediately recognized the specimen as unique. Laboratory studies have since

shown that the specimen is a meteorite from the

Moon; the first one ever found on Earth.

Schutt was not out that day primarily to search

for meteorites. He was guiding a visitor, Ian

Whillans of Ohio State University, on a reconnaissance trip to examine the regional configuration of the ice sheet. After a 31 km snowmobile

ride over long stretches of rough snowdrifts they

decided to turn back. A steady wind and blowing

snow made visibility poor, so it was by sheerest

chance that Schutt saw the plum-sized specimen

as they cruised near the edge of the icefield.

Schutt photographed the meteorite in situ

(Figure 75) and collected it by the customary

sterile procedures. That evening the weather

deteriorated so rapidly that further field work

became impossible. The lunar rock was the final

addition to that season's trove of 373 specimens.

Months later, at the NASA Johnson Space

Center in Houston, Roberta Score unpackaged

Ursula B. Marvin, Smithsonian Astrophysical Observatory, 60

Garden Street, Cambridge, Massachusetts 02138.

the meteorite in a nitrogen-filled processing cabinet (Frontispiece). She described it as an unusual

looking sample with an abundance of angular

gray to white clasts, from about 1 to 8 mm in

size, set in a black matrix (Score, 1982). It

weighed 31.4 grams and measured 3 X 2.5 X 3

centimeters. It was assigned the name Allan Hills

81005 (ALHA81005).

From a thin section, made at the Smithsonian

Institution in Washington, Brian Mason classified

the rock as an anorthositic breccia. He found the

white clasts to consist mainly of Ca-rich plagioclase, making the meteorite much more feldspathic than the eucrites. Mason wrote in the

Antarctic Meteorite Newsletter that "some of the

clasts resemble the anorthositic clasts described

from lunar rocks" (Mason, 1982).

News spread quickly of the Antarctic meteorite that looked like a lunar rock, but the story

broke too late for sample requests to be submitted in time for the September 1982 meeting of

the Meteorite Working Group. Unwilling to wait

until the following April, the MWG issued a

special Newsletter in November announcing the

availability of samples for initial characterization.

The intent was to obtain sufficient general information from thin sections and matrix chips to

guide the formation of a multidisciplinary consortium to study individual clasts. The deadline

for submitting sample requests was 1 December

1982. In order to give investigators an equal

chance to report their findings, all were asked to

delay public announcement of their results until

the 14th annual meeting of the Lunar and Plan95
96 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

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NUMBER 26 97

FIGURE 75—An in situ photograph of the meteorite

ALHA81005 as it lay on the ice. It is a rounded individual

with an angular notch where a piece was broken off. White

clasts are visible beneath a thin, frothy fusion crust.

etary Science Conference to be held in Houston

in March 1983.

On 4 December, the Meteorite Working

Group held a special session at which threefourths of the participants were conscripts substituting for regular members who had submitted

proposals. Twenty-five requests were received

and twenty-two were approved. The remaining

three were postponed for integration into the

consortium. The types of studies authorized for

the initial round were electron microprobe analyses of thin sections (with five sections being

shared by eight investigators), instrumental and

radiochemical neutron activation analyses of

bulk and matrix samples, measurements of reflectance spectra, ferromagnetic resonance, noble gas abundances, nuclear particle tracks, oxygen isotopes, and cosmogenic isotopes.

At the special session on Allan Hills 81005,

held at the Houston Conference on St. Patrick's

Day, a wholly unprecedented degree of unanimity prevailed. All participants agreed that the

specimen probably came from the Moon; most

said it positively came from the Moon; none said

it did not come from the Moon.

The fragmental fabric of the breccia is illustrated in Figure 76, a photomosaic of thin section

ALHA81005,22. A heterogeneous array of mineral and rock clasts and masses of devitrified glass

are embedded in a dark brown, glassy matrix.

The matrix, defined as material with a grain size

less than 25 /xm, occupies about 60%, and the

clasts about 40% of the area. Some clasts show

shock effects, such as crushing and partial optical

randomization of crystals, but others, including

several delicately twinned feldspars, are unshocked.

As first suggested by Mason, the white clasts

do indeed resemble those of lunar highlands

anorthositic rocks. Plagioclase (An94 to An98) is

the most abundant component in the clasts and

glasses, including the dark brown matrix glass.

Colorless, pale yellow, and light orange glass

spherules are scattered throughout the breccia,

and patches of highly vesicular, swirly glass,

formed by the remelting of glass-bonded agglutinates, occur in the matrix (Figure 77). The

spherules and reworked agglutinates identify the

rock as a soil breccia.

The most common clasts are recrystallized

breccias, melt rocks, and devitrified glasses, but

the breccia also contains a few clasts of cataclastic

ferroan anorthosites, anorthositic gabbros, and

troctolites, some of which are probably pristine.

The largest clast in thin section ALHA81005,22

is a cataclastic ferroan anorthositic gabbro (Figure 78A) consisting of 87% plagioclase (An96-

An98) and 13% pigeonite (En64Fs34Wo2) and ferroaugite (En25Fs32Wo42). This rock clearly belongs to the well-established pristine ferroan anorthosites, but it is more Fe-rich than previously

analyzed samples.

A different type of anorthositic gabbro consists

of chains of pyroxenes and olivines lying in a

matrix of granulitic plagioclase (Figure 78B). The

plagioclase is An97; the finely exsolved pyroxenes
98 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

5 m m

FIGURE 76.—A photomosaic of thin section

ALHA81005,22 showing the heterogeneous array of clasts

and glasses in the dark glassy matrix. Clasts 1-4 are shown

at higher magnifications in Figures 77 and 78.

FIGURE 78.—Three types of lithic clasts in section

ALHA81005,22. A, Cataclastic anorthositic gabbro in which

the plagioclase is partially optically randomized by shock

pressure (clast 2 in Figure 76). B, Anorthositic gabbro with

a quasi-cumulate texture. Chains of olivines and pyroxenes

lie amid granulitic plagioclase, but large clasts of twinned

plagioclase are also present indicating that the rock is a

recrystallized breccia (clast 3 in Figure 76). c, Clast consisting

of a 430-jum plagioclase lath attached to a mass of black

glass. The gray-patterned areas in the lath are patches of

glass of the same composition as the plagioclase (clast 4 in

Figure 76). (All three clasts photographed in transmitted

light). D, Photomicrograph in reflected light of the black

glass, showing five phases: rows of opaque crystallites of

armalcolite and one larger crystallite of ulvospinel on edge

of glass (lower left), brighter and duller bands of glass, and

two minute spherules of metallic Fe (bright dots amid crystallites in lower half of picture). This coarse clast may be a

fragment of mare basalt.

FIGURE 77.—Clasts and matrix textures in thin section

ALHA81005,22. A, Lopsided spherule of colorless glass lies

adjacent to a swirly mass of tawny-brown glass full of minute

vesicles, which appear as black dots. The vesicular glass is a

remelted glass-bonded agglutinate, a type of particle that is

abundant in lunar soils. B, Small clast (a) of possible low-K

mare basalt (Clast 1 in Figure 76) lies between a light-colored

granulite (b) formed by the recrystallization of an impact

breccia, and a rounded mass of light brown, devitrified glass

(c). (Both photomicrographs taken in transmitted light).
NUMBER 26 99
100 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

are En38_45Fs3o-44Woi1_32; the olivine is Fo40, by

far the most iron-rich mafic mineral reported to

date in ALHA81005. Three large crystals of

twinned plagioclase (An97) are also present, indicating that the clast is a recrystallized breccia

despite the appearance of a cumulate texture.

Several clasts of mare basalts have been found

mixed with the predominantly highlands materials in the breccia. Fragments of Very Low

Titanium (VLT) mare basalt were discovered

in thin sections by Tremaine and Drake (1983)

and Ryder and Ostertag (1983). In section

ALHA81005,22 a clast consisting of a single 430

lim lath of plagioclase (An97) attached to a mass

of black Ti-rich glass may be a fragment of hightitanium mare basalt (Figure 78C,D). The glass is

studded with rows of opaque crystallites, chiefly

armalcolite, (Fe,Mg)Ti2O5, and one larger crystallite of ulvospinel (FeTi2O4). The black glass

contains about 0.22 wt.% K2O, more than twice

the amount measured in the plagioclases of the

breccia. The glass appears to be a sample of

mesostasis from a medium-grained basalt (Marvin, 1983).

A small diabasic clast (Figure 77B) consisting

of 86% bytownite (An85_89Abio-i40r0.8-i.i), augite, and glassy mesostases containing silica glass,

K-feldspar, apatite, and ilmenite may represent

a low-potassium mare basalt (Marvin, 1983).

A strong indication of lunar origin is provided

by the ratios of manganese to iron oxides in the

pyroxene minerals of the clasts. Systematic differences in FeO/MnO partitioning in rocks from

different sources were first demonstrated by

Laul and Schmitt (1973), and subsequent studies

have established separate fields for lunar rocks

and the various classes of achondritic meteorites.

Values for the pyroxenes in ALHA81005 plot in

the lunar field as shown in Figure 79.

The major-element composition of the bulk

sample closely resembles highland materials from

the Apollo 16 and Luna 20 missions. However,

the contents of minor and trace elements, particularly potassium, rare earth elements, and phosphorus (KREEP) are markedly lower than those

found in the highlands samples previously analyzed. Remote sensing analyses of the lunar surface, by orbiting spacecraft and ground-based

telescopes, indicate that areas of KREEP-poor

anorthositic crust occur along the far eastern

limb of the Earth-facing side, and on the farside

of the Moon. Some investigators (e.g., Pieters,

1983) are searching these regions for a youthful

impact crater large enough to have been the

source of ALHA81005. The site should lie

within 100 km or so of mare surfaces of appropriate compositions to account for the basalt

clasts that were present in the regolith.

Other lines of evidence for a lunar origin

include the oxygen isotopic ratios that bear a

distinctly lunar signature (Mayeda et al., 1983),

the presence in the matrix of solar wind-implanted noble gases (He, Ne, Ar, Kr, and Xe) in

concentrations and relative abundances similar

to those in gas-rich lunar soils and breccias (Bogard and Johnson, 1983b), and the absence of

galactic particle tracks in the mineral grains,

consistent with a short flight time in space (Sutton

and Crozaz, 1983). These and additional investigations are reported in a special issue of Geophysical Research Letters (1983) devoted to

ALHA81005.

This sample was clearly spalled off the Moon

into an Earth-crossing orbit from a site not visited

by either the United States Apollo missions or

the Soviet Union's Luna missions. Thus, that

end-of-season snowmobile trip to the Middle

Western Icefield of the Allan Hills region has

been nicknamed "the Apollo 18 mission" (Korotev, Haskin, and Lindstrom, 1983).

Our examination of ALHA81005 has taught

us, once again, that natural events frequently

confound the results of all our calculations. Predictions from experimental impacts and computer modeling told us that the only material

that could escape the Moon would come from

deep below the target area of an impacting projectile and be shock-melted to glass or crushed

and dispersed as glassy droplets. But, contrary to

these predictions, ALHA81005 is not a rock

derived from deep in the lunar crust; it is a

welded surface soil, no more highly shocked and

glassy than many a sample that the astronauts

lifted off the lunar surface with tongs. A new
NUMBER 26 101

model is now being constructed (Melosh, 1983),

which involves the spalling off of blocks of surface materials at low pressures in front of oblique

impacts.

Most of the meteorites collected in the past are

believed to have come from asteroids, with a few

possibly derived from comets. During the past

two centuries nearly 700 meteorite falls have

been witnessed and some of the fireballs have

been photographed. All of the well-documented

trajectories show that the meteorites were following elliptical orbits that originated in the asteroid

belt between Mars and Jupiter. Lunar ejecta

must also fall on Earth whenever huge meteorites

impact the Moon with sufficient energy to accelerate target materials above the lunar escape

velocity of 2.4 km per second. Statistical studies

have suggested that such impacts happen very

infrequently, and it is likely that none has occurred in historic time. We now know, however,

that such an event did occur sometime within the

past few million years while the great ice sheet

has covered Antarctica. Perhaps the fall occurred

less than a million years ago. The first attempt

to measure the terrestrial age (time since the fall

to Earth) of ALHA81005 gave ambiguous results

(Evans and Reeves, 1983). However, as shown

by Nishiizumi (herein, p. 105), the oldest terrestrial ages yet measured on Antarctic meteorites

are in the order of 700,000 years. If meteorite

concentrations occur on older patches of ice they

have not yet been discovered. We await with

much interest age determinations on the other

meteorites and, if possible, on ice itself at the

Middle Western Icefield.

Systematic searches of the Middle Western

Icefield have not yet been made, but that area

appears promising not only because of the lunar

meteorite but because eight specimens (including

a rare enstatite achondrite) were discovered

there during two brief helicopter visits in the

1978-1979 season. Present plans call for a camp

to be set up nearby and a careful search made in

the 1983-1984 season. Meanwhile, the discovery

of ALHA81005 has raised many questions. Did

this specimen fall on Earth as a single stone, or

did it fall as one piece of a great mass of lunar

wt.% FeO

FIGURE 79.—The partitioning of FeO and MnO in lunar

samples and achondritic meteorites. The black dots, which

represent values measured in pyroxenes of ALHA81005,

plot in the lunar field although some of them extend the

previously determined range toward achondrite values. The

pyroxene ratios plot on and above the lunar whole rock

trendline while the olivine ratios (triangles) plot on and

below it, thus demonstrating a lunar bulk composition. (The

fields for achondrites are taken from Stolper et al., 1979).

debris that was scattered broadcast over our rotating planet? Or did ALHA81005 break off

from a larger incoming mass that exploded in

the atmosphere and showered fragments over

Antarctica? The possibility that this specimen is

a shower fragment will inspire the field party to

search the area with high hopes of discovering

additional pieces of this meteorite from the

Moon.

Would we have recognized this unique meteorite as a lunar rock if we had never examined

samples from the Moon? Perhaps not, if we had

found it much more than a decade ago, because

the anorthositic character of the lunar crust came

to us as a complete surprise at the time of the

Apollo 11 mission. Even then, however, one of

the Surveyor modules had sent back analyses

indicating a Ca-Al-rich type of crustal rock, and

orbital missions have since produced compositional maps of much of the lunar surface. It

seems likely that the anorthositic character of

ALHA81005 and its marked chemical, mineralogical, and isotopic differences from the basaltic

achondrites would have persuaded some scientists to propose a lunar origin for it.
102 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

The discovery of a lunar meteorite has given

new credibility to the hypothesis, first proposed

about five years ago, that the shergottites, a rare

class of achondrites represented by nine specimens (two from Antarctica and seven from other

continents) may have come from Mars. Originally, this hypothesis was based on isotopic age

determinations, which showed that the shergottites crystallized only about 1.3 X 109

 years ago.

Age determinations on other meteorites show us

that the asteroids were already cold and solid

about 4.5 X 109 years ago, soon after the solar

system formed. Even Earth's moon ceased flooding its basins with basaltic lava flows about 3.1 X

109 years ago. Only a larger body, such as Mars,

would be well-insulated enough to retain heat

and remain volcanically active to comparatively

recent times. Mars has huge volcanic cones on its

surface, and crater counts on the surrounding

lava flows show them to be young in comparison

to the ancient, more heavily cratered terranes.

Can the shergottites be samples of these flows?

Recent measurements show that nitrogen, argon, krypton, and xenon trapped in glassy lenses

in one of the Antarctic shergottites (EETA

79001) are similar in relative abundances and

isotopic ratios to those of the gases in the Martian

atmosphere, measured by the Viking Landers

(Bogard and Johnson, 1983a; Becker and Pepin,

1983).

The case for Martian shergottites is still highly

speculative. The escape velocity from Mars is

about 5 km per second, an acceleration that

seems prohibitive to many investigators. In the

past, many have argued that we could not expect

to find Martian rocks on Earth unless we also

find samples from our closer neighbor, the

Moon. That objection, at least, has now been

removed.

Antarctica has proved to be a rich source of

meteorites, which lie on certain patches of bare

ice awaiting discovery. To journey to Antarctica

is an elegant way to add to our collections of

planetary samples while we await future missions

into space. The discovery of a lunar sample on

that windy January day in the Allan Hills has

opened an awesome new potential and enhanced

immeasurably the excitement of the Antarctic

meteorite program.

This work was supported in part by NASA

grant NAG 9-29.

Additional papers on this meteorite may be

found in a special issue of Geophysical Research

Letters, 10 (September, 1983).

Literature Cited

Becker, R.H., and R.O. Pepin

1983. Heavy Nitrogen in Glass from Antarctica Meteorite EETA79001 [Abstract]. EOS, 64:253.

Bogard, D.D., and P.Johnson

1983a. Martian Atmospheric Gases Trapped in the

EETA79001 Shergottite? In Lunar and Planetary

Science XIV: Session on Meteorites from Earth's Moon,

pages 53-54. Houston: Lunar and Planetary Institute.

1983b. Trapped Solar Gases in the ALHA81005 Lunar

(?) Meteorite. In Lunar and Planetary Science XIV:

Session on Meteorites from Earth's Moon, pages 1-2.

Houston: Lunar and Planetary Institute.

Evans, J.C., andJ.H. Reeves

1983. Aluminum-26 Content of ALHA81005. In Lunar

and Planetary Science XIV: Session on Meteorites from

Earth's Moon, pages 6-7. Houston: Lunar and

Planetary Institute.

Korotev, R.L., L.A. Haskin, M.M. Lindstrom

1983. Lunar Highlands Breccia 81005 (ALHA): So

Apollo 18 Flew, but Where Did It Sample? In

Lunar and Planetary Science XIV: Session on Meteorites

front Earth's Moon, pages 12-13. Houston: Lunar

and Planetary Institute.

Laul,J.C., and R. Schmitt

1973. Chemical Composition of Apollo 15, 16, and 17

Samples. In Proceedings of the Fourth Lunar

Science Conference. Geochimica et Cosmochemica

Ada, supplement 4, 2:1349-1367.

Marvin, Ursula B.

1983. The Discovery and Initial Characterization of Allan Hills 81005: The First Lunar Meteorite. Geophysical Research Letters, 10:775-778.

Mason, Brian

1982. In Antarctic Meteorite Newsletter, 5 (4).

Mayeda, T.K., R.N. Clayton, and C.A. Molini-Velsko

1983. Oxygen and Silicon Isotopes in ALHA 81005.

Geophysical Research Letters, 10:799-800.

Melosh, H.J.

1983. Impact Ejection, Spallation and the Origin of Cer-
NUMBER 26 103

tain Meteorites. Lunar and Planetary Science XIV:

Session on Meteorites from Earth's Moon, pages 21 -

22. Houston: Lunar and Planetary Institute.

Pieters, Carle

1983. If ALHA81005 Came from the Moon, Can We

Tell from Where? In Lunar and Planetary Science

XIV: Session on Meteorites from Earth's Moon, pages

27-28. Houston: Lunar and Planetary Institute.

Ryder, G., and R. Ostertag

1983. ALHA 81005: Petrographic Components of the

Target. In Lunar and Planetary Science XIV: Session

on Meteorites from Earth's Moon, pages 29-30. Houston: Lunar and Planetary Institute.

Score, Roberta

1982. In Antarctic Meteorite Newsletter 5 (4).

Stolper, E., H.Y. McSween, Jr., andJ.F. Hays

1979. A Petrogenetic Model of the Relationship between Achondritic Meteorites. Geochimica et Cosmochimica Acta, 43:589-592.

Sutton, S.R., and G. Crozaz

1983. Thermoluminescence and Tracks: Constraints on

the History of This Unusual Meteorite. In Lunar

and Planetary Science XIV: Sessions on Meteorites from

Earth's Moon, pages 33-34. Houston: Lunar and

Planetary Institute.

Tremaine, A.H., and M.J. Drake

1983. Meteorite from the Moon: Petrology of Terrae

Clasts and One Mare Clast in ALHA 81005,9. In

Lunar and Planetary Science XIV: Session on Meteorites

from Earth's Moon, pages 35-36. Houston: Lunar

and Planetary Institute.
Cosmic-Ray-Produced Nuclides in

Victoria Land Meteorites

Kunihiko Nishiizumi

In the last few years measurements of cosmicray-produced nuclides in Antarctic meteorites

have been carried out by several groups. At the

present time, we have measured

 53Mn (ti/2= 3.7

X 106 y) in 153 meteorites (62 Victoria Land

meteorites and 91 Yamato meteorites) by the

destructive neutron-activation method (Nishiizumi, Imamura, et al., 1979; Nishiizumi et al.,

1981; Nishiizumi, Arnold, Imamura, etal., 1982;

Nishiizumi, Arnold, Elmore, et al., 1983; Imamura et al., 1979, Goswami and Nishiizumi,

1983) and

 36C1 (t1/2= 3.0 X 105

 y) in 62 Antarctic

meteorites by Accelerator Mass Spectroscopy

(Nishiizumi, Arnold, et al., 1979, Nishiizumi et

al., 1981, 1983, and Nishiizumi, unpublished).

26Al (t 1/2 = 7.2 X 10.5 y) has been measured in

129 Victoria Land meteorites by the Battelle

group using nondestructive gamma-ray analysis

(Evans et al., 1979, 1982). In addition to the

above data, nine

 10Be (ti/2 = 1.6 X 106

 y), and

eighteen

 14C (5730 y) measurements, and twentysix sets of noble gas data are also available for

our study.

Cosmogenic nuclide concentrations in a meteorite give us the cosmic-ray exposure age in

space and terrestrial age on the earth, if we know

the expected equilibrium concentrations and

half-lives. It is important to measure two or more

cosmogenic nuclides in the same meteorite.

Table 9 is a compilation of published and

Kunihiko Nishiizumi, Department of Chemistry, B-017, University

of California, San Diego, La Jolla, California 92093.

unpublished data for Victoria Land meteorites

for which measurements of more than one nuclide are available. This table also includes the

exposure age and terrestrial age of these meteorites. The exposure age was calculated from the

cosmogenic

 21Ne content; the shielding condition

was corrected by the

 22Ne/21Ne ratio or from

cosmogenic

 40K content. The terrestrial age of

the meteorite was calculated from

 36C1 or 14C

content, comparing it with the saturated activity

level that was expected at the time of fall on

Antarctica. The details are discussed in a recent

paper (Reedy et al., 1983).

The measurement of terrestrial age is an important subject for Antarctic meteorites. The

terrestrial ages of non-Antarctic stone meteorites

are less than 3 X 104 years, usually much less.

However the terrestrial ages of Allan Hills meteorites range from 1 X 104

 (ALHA77256) to 7

X 105 years (ALHA77002). This age not only

gives us information on the accumulation mechanism of meteorites and the history of the Antarctic ice sheet, but also about ancient meteorite

influx rates. Our interest was focused on Allan

Hills meteorites for terrestrial age measurements. So far, several features have appeared.

Meteorites found on the northwest part of the

Allan Hills blue ice region have shorter terrestrial ages than meteorites found on the southeast

part. Probably this feature gives key information

for the accumulation mechanism of Allan Hills

meteorites and glaciology. On the other hand

there is no clear correlation between the terres105
TABLE 9.—Activity (dpm/kg), exposure age, and terrestrial age of meteorites in which

more than one nuclide has been measured (numbers in parentheses indicate half-life of

each nuclide).1

Specimen

number

ALLAN HILLS

ALHA76001

ALHA76002

ALHA76003

ALHA76004

ALHA76005

ALHA76006

ALHA76007

ALHA76008

ALHA76009

ALHA77001

ALHA77OO2

ALHA77003

ALHA77004

ALHA77009

ALHA77015

ALHA77081

ALHA77167

ALHA77214

ALHA77216

ALHA77230

ALHA77249

ALHA77250

ALHA77255

ALHA77256

ALHA77257

ALHA77258

ALHA77260

ALHA77261

ALHA77262

ALHA77270

ALHA77272

ALHA77273

ALHA77278

ALHA77280

ALHA77282

ALHA77283

ALHA77285

ALHA77289

ALHA77290

ALHA77294

ALHA77297

ALHA77299

ALHA77304

ALHA78043

Class

L6

IA

L6

LL3

Eu

H6

L6

H6

L6

L6

L5

C3

H4

H4

L3

H?

L3

L3

L3

L4

L3

IA

Anom

Di

Ur

H6

L3

L6

H4

L6

L6

L6

LL3

L6

L6

IA

H6

IA

IA

H5

L6

H3

L4

L6

53Mn

(3.7xl06y)

443±33

556±21

431±25

390±36

453±33

332±26

22±3

477±34

422±13

255±8

317±13

326±13

162±8

137±7

151±6

348±14

362±15

181±9

565±22

385±15

400±21

181±8

434±18

150±8

302±13

327±13

494±20

213±11

224±11

264±11

325±16

384±17

437±17

394±16

534±21

504±20

433±17

428±17

317±19

211±9

457±22

Activity2

10Be 26A1

(1.6Xl06y) (7.2X105y)

58±2

89±9

51±1

45±4

3.9±0.5 11±1

52±5

30±3

19±2 45±5

52±5

32±2

36±4

42±4

37±2

15±1 56±6

40±3

51±3

37±2

29±2

37±2

36±4

47±5

40±3

18±2 35±4

31±2

28±3

49±3

38±4

67±4

70±7

43±4

50±3

33±3

36C1

(3.0X105y)

14.1±0.5

9.4±1.0

20.1±1.2

4.6±1.1

18.4±1.2

15.2±0.5

10.7±0.2

17.O±O.8

14.9±0.5

15.6±0.2

19.2±0.2

9.8±0.8

12.2±0.4

ll.l±0.6

6.7±0.1

6.6±0.3

6.2±0.3

10.9±0.7

12.2±0.3

12.1±0.4

17.5±O.3

13.6±0.5

15.3±0.3

15.1±0.3

20.8±0.6

19.6±0.2

18.9±0.8

7.3±0.3

1 4 C

(5730y)

<1.0

<1.7

<1.2

<1.7

0.62±0.06

0.65±0.02

0.35±0.03

16.0±1.5

<0.5

1.07±0.24

1.6±0.3

<0.60

Exposure

age

10«y

45

410

53

26

10

28

33

(1.5)

20

20

3.1

5.6

2.4

3.3

30

10

1.8

4.6

21

36

Terrestrial

age

103y

200±80

>34

>32

>34

100±70

<120

700±160

110±70

l70±70

320±70

120±80

180±70

160±70

<130

11±1

360±90

270±70

310±80

530±70

530±80

560±80

320±90

270±70

270±70

110±70

220±70

170±70

17O±7O

30±2

80±40

80±80

490±80

1

 Average saturated activity: "Mn: 414±50;

 10Be: 20±2; 26A1: 60±7(L), 56±7(H); 36C1: 22.8±3.1;

2

 Activity:

 5:1Mn: dpm/kg (Fe+'A Ni); 10Be, 26A1, I4C: dpm/kg meteorite; 36C1: dpm/kg metal.

4C: 60.
TABLE 9.—Continued.

Specimen

number

ALHA78076

ALHA78084

ALHA78102

ALHA78105

ALHA78109

ALHA78112

ALHA78114

ALHA78115

ALHA78128

ALHA78130

ALHA78131

ALHA78132

ALHA78232

ALHA81005

BATES NUNATAK

BTNA78002

DERRICK PEAK

DRPA78008

DRPA78009

METEORITE HILLS

META78001

META78002

META78005

META78006

META78010

META78028

MOUNT BALDR

MBRA76001

MBRA76002

PURGATORY PEAK

PGPA77006

RECKLING PEAK

RKPA78003

Class

H6

H4

H5

L6

LL5

L6

L6

H6

H5

L6

L6

Eu

IVA

A

L6

IIB

IIB

H4

L6

L6

H6

H5

L6

H6

H6

IA

L6

53Mn

(3.7xi06y)

427±18

318±13

462±21

444±28

347±16

360±14

334±14

380±15

402±19

376±14

424±18

2.7±0.2

65±3

429±17

394±34

355±26

569±23

363±16

1(>Be

(1.6xl06y)

18±2

21±2

14±2

16±2

18±2

4.1±0.5

Activity2

26

 Al

(7.2X105y)

52±4

35±3

61±7

46±3

42±3

38±2

43±3

34±2

51±4

40±3

68±4

46±3

0

53±3

47±3

44±3

60±4

56±3

56±3

50±3

36C1

(3.0X105y)

16.9±0.5

16.4±0.5

14.0±0.6

12.5±0.3

12.4±0.5

13.4±0.5

7.8±0.3

21.6±0.6

15.2±0.4

20.7±0.5

9.3±0.4

9.9±0.2

19.5±0.4

.032±0.004

0.20±0.01

20.5±0.8

21.0±0.5

20.0±0.4

20.9±0.5

21.8±0.5

21.3±0.6

18.4±0.5

19.8±0.4

Exposure

MC age

(5730y)

 1Ob

y

1.41±0.24 37

11

1.01±0.03

1.19±0.30 6

7

Terrestrial

age

lO^y

130±70

140±70

210±80

260±70

260±70

230±70

460±80

<90

17O±7O

<110

380±80

360±70

<130

<120

<100

<120

<100

<90

32±1

31±3

90±70

<130

References:

Column 1: Imamura et al., 1979; Nishiizumi et al., 1979, 1981, 1983; Nishiizumi, Arnold, Imamura, et al., 1982;

Goswami and Nishiizumi, 1983.

Column 2: Moniot et al., 1982; Nishiizumi, Arnold, Imamura, et al., 1982; Nishiizumi, Arnold, Klein, et al., 1982;

Tunizetal., 1983.

Column 3: Evans et al., 1979, 1982; Evans, personal communication; Tuniz et al., 1983.

Column 4: Nishiizumi, Arnold, et al., 1979; Nishiizumi et al., 1981, 1983.

Column 5: Fireman, 1979, 1980, 1983; Fireman and Norris, 1981; Andrews et al., 1982, Nishiizumi, unpublished

data.

Column 6: Nagao and Takaoka, 1979; Nitoh et al., 1980; Schultz et al., 1980; Weber and Schultz, 1980; Takaoka

et al., 1981; Nautiyal et al., 1982; Nagao et al., 1983; Weber et al., 1983.

Column 7: Nishiizumi, herein.
108 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

trial age of a meteorite and its weathering features. This indicates that many meteorites stayed

in the ice for a long time and weathering only

began when the specimen was exposed at the ice

surface. Allan Hills meteorites have a wide range

of terrestrial ages and are generally older than

other Victoria Land meteorites and Yamato meteorites.

Although the cosmogenic noble-gas data are

important for meteorite bombardment history in

space, relatively small amounts of data are available for Allan Hills meteorites compared to Yamato meteorites. Based on both cosmogenic stable (noble gas) and radioactive nuclide data, at

least four Antarctic meteorites showed clearly

multistage irradiation records. They are

ALHA76008, Yamato 7301, 74028, and 74116

(Nishiizumi et al., 1978, 1979, Nishiizumi, Arnold, Imamura, et al., 1982; Imamura et al.,

1979). The multistage irradiation model asserts

that the meteorite was irradiated in a heavily

shielded position in the parent body for a long

time. During this period most of the cosmogenic

stable nuclides (noble gas and

 40K) were produced. The parent body was then fragmented,

initiating the second-stage irradiation by exposing the small preatmospheric bodies to cosmic

rays for a short time so that the long-lived radioactive nuclides were not saturated. Except for

Antarctic meteorites, Jilin (Kirin) is the only

stony meteorite definitely known to have had a

multistage irradiation record.

An iron meteorite, Derrick Peak A78008, contains the lowest concentration of cosmogenic radionuclides yet measured among Antarctic meteorites. This object is known to be a shower

fragment of DRPA78001-78009 (Clarke, 1982).

Based on a low

 53Mn result of (2.7±0.2 dpm/

kg), the preatmospheric size of this group of

Derrick Peak meteorites was more than 3.3 m in

diameter, or more than 150 tons in weight.

Combined analysis of cosmogenic nuclides and

cosmic-ray track data in an aliquot sample provides information on size and location of a meteorite in the preatmospheric body. Such analysis

is extremely useful to check on pairing of Antarctic meteorites. For example, L3 chondrites

ALHA77015, 77167, and 77260 could be fragments from a single meteorite with radius ~25

cm (Goswami and Nishiizumi, 1983). On the

other hand L6 chondrites ALHA77273 and

77280, which were previously suggested to be a

single fall of a meteorite, could not be fragments

from a single meteorite (Goswami and Nishiizumi, 1983).

This research was supported in part by NASA

Grant NGL 005-009-148.

Literature Cited

Andrews, H.R., R.M. Brown, G.C. Ball, N. Burn, Y. Imahori, J.C.D. Milton, WJ. Workman, and E.L. Fireman

1982.

 14C Content of Antarctic Meteorites Measured

with the Chalk River MP Tandem Accelerator. In

Abstracts, Fifth International Conference on Geochronology, Cosmochronology, and Isotope Geology,

Nikko, Japan, pages 8-9.

Clarke, R.S.,Jr.

1982. The Derrick Peak, Antarctica, Iron Meteorites.

Meteoritics, 17:129-134.

Evans, J.C., L.A. Rancitelli, and J.H. Reeves

1979.

 2hAl Content of Antarctic Meteorites: Implications

for Terrestrial Ages and Bombardment History.

In Proceedings of the Tenth Lunar and Planetary

Science Conference, pages 1061—1072. New York:

Pergamon Press.

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, Catalog of Meteorites from Victoria Land, Antarctica, 1978-1980. Smithsonian Contributions to the

Earth Sciences, 24:70-74.

Fireman, E.L.

1979.

 I4C and 39Ar Abundances in Allan Hills Meteorites. In Proceedings of the Tenth Lunar and Planetary

Science Conference, pages 1053-1060. New York:

Pergamon Press.

1980. Carbon-14 and Argon-39 in ALHA Meteorites.

In Proceedings of the Eleventh Lunar and Planetary

Science Conference, pages 1215-1221. New York:

Pergamon Press.

1983. Carbon-14 Ages of Antarctic Meteorites. In Lunar

and Planetary Science XTV, pages 195-196. Houston: Lunar and Planetary Institute.

Fireman, E.L., and T. Norris

1981. Carbon-14 Ages of Allan Hills Meteorites and Ice.

In Proceedings of the Twelfth Lunar and Planetary
NUMBER 26 109

Science Conference,, pages 1019-1025. New York:

Pergamon Press.

Goswami, J.N., and K. Nishiizumi

1983. Cosmogenic Records in Antarctic Meteorites.

Earth and Planetary Science Letters, 64:1-8.

Imamura, M., K. Nishiizumi, and M. Honda

1979. Cosmogenic

 53Mn in Antarctic Meteorites and

Their Exposure History, Memoirs of the National

Institute of Polar Research (Japan), special issue,

15:227-242.

Moniot, R.K., T.H. Kruse, W. Savin, C. Tuniz, T. Milazzo,

G.S. Hall, D. Pal, and G.F. Herzog

1982. Beryllium-10 Contents of Stony Meteorites and

the Neon-21 Production Rate. Lunar and Planetary Science XIII, pages 536-537. Houston: Lunar

and Planetary Institute.

Nagao, K., and N. Takaoka

1979. Rare Gas Studies of Antarctic Meteorites. Memoirs

of the National Institute of Polar Research (Japan),

special issue, 12:207-222.

Nagao, K., N. Takaoka, and K. Saito

1983. Rare Gas Studies of the Antarctic Meteorites. In

Eighth Symposium on Antarctic Meteorites, pages

83-84. Tokyo: National Institute of Polar Research.

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 Plantary Institute.

Nishiizumi, K.

1978. Cosmic-Ray-Produced

 53Mn in Thirty-one Meteorites. Earth and Planetary Science Letters, 41:91-

100.

Nishiizumi, K.,J.R. Arnold, D. Elmore, R.D. Ferraro, H.E.

Gove, R.C. Finkel, R.P. Beukens, K.H. Chung, and

L.R. Kilius

1979. Measurements of

 36C1 in Antarctic Meteorites and

Antarctic Ice using a Van de Graaff Accelerator.

Earth and Planetary Science Letters, 45:285-292.

Nishiizumi, K.,J.R. Arnold, D. Elmore, X. Ma, D. Newman,

and H.E. Gove

1983.

 36C1 and 53Mn in Antarctic Meteorites and 10Be36C1 Dating of Antarctic Ice. Earth and Planetary

Science Letters, 62:407-417.

Nishiizumi, K., J.R. Arnold, M. Imamura, T. Inoue, and M.

Honda

1982. Cosmogenic Radionuclides in Antarctic Meteorites. In Seventh Symposium on Antarctic Meteorites,

pages 52-54. Tokyo: National Institute of Polar

Research.

Nishiizumi, K., J.R. Arnold, J. Klein, and R. Middleton

1982.

 10Be and Other Radionuclides in Antarctic Meteorites and in Associated Ice. Meteoritics, 17:260-

261.

Nishiizumi, K., M. Imamura, and M. Honda

1978. Cosmic Ray Induced

 53Mn in Yamato-7301(j),

-7305(k) and -7304(m) Meteorites. Memoirs of the

National Institute of Polar Research (Japan) special

issue, 8:209-219.

1979. Cosmic Ray Produced Radionuclides in Antarctic

Meteorites. Memoirs of the National Institute of Polar

Research (Japan), special issue, 12:161-177.

Nishiizumi, K., M.T. Murrell, J.R. Arnold, D. Elmore, R.D.

Ferraro, H.E. Gove, and R.C. Finkel

1981. Cosmic-Ray-Produced

 36C1 and 53Mn in Allan

Hills-77 Meteorites. Earth and Planetary Science

Letters, 52:31-38.

Nitoh, O., M. Honda, and M. Imamura

1980. Cosmogenic K-40 in Antarctic Meteorites. Memoirs of the National Institute of Polar Research (Japan),

special issue, 17:189-201.

Reedy, R.C, J.R. Arnold, and D. Lai

1983. Cosmic-Ray Record in Solar System Matter. Science, 219:127-135.

Schultz, L., H. Palme, B. Spettel, H. Wanke, and H.W.

Weber

1980. Chemistry and Noble Gases of the Unusual Stony

Meteorite Allan Hills A77081. In Lunar and Planetary Science XI, pages 1003-1005. Houston: Lunar

and Planetary Institute.

Takaoka, N., K. Saito, Y. Ohba, and K. Nagao

1981. Rare Gas Studies of Twenty-Four Antarctic Chondrites. Memoirs of the National Institute of Polar

Research (Japan), special issue, 20:264-275.

Tuniz, C, D.K. Pal, R.K. Moniot, W. Savin, T.H. Kruse,

G.F. Herzog, and J.C. Evans

1983. Recent Cosmic Ray Exposure History of ALHA

81005. Geophysical Research Letters, 10:804-

806.

Weber, H.W., O. Braun, L. Schultz, and F. Begemann

1983. The Noble Gas Record in Antarctic and Other

Meteorites. Zeitschriftfur Naturforschung, 38a:267-

272.

Weber, H.W., and L. Schultz

1980. Noble Gases in Ten Stone Meteorites from Antarctica. Zeitschrift fur Naturforschung, 35a:44-49.
Bulk Chemical Analyses

of Antarctic Meteorites,

with Notes on Weathering Effects

on FeO, Fe-metal, FeS, H2O, and C

Eugen e Ja rosewich

In addition to a large number of ordinary

chondrites, the discovery and subsequent collection of a large number of the Antarctic meteorites has yielded a considerable selection of rare

types. Among these rare types are achondrites,

carbonaceous chondrites, a unique "moon meteorite," and several type 3 chondrites, to name a

few. Since these meteorites are rare, they are the

object of extensive studies by researchers from

various disciplines, and their data are compared

with the data from existing specimens in our

collections.

The bulk chemical analysis of some of these

rare meteorites was undertaken as a part of a

broader study of Antarctic meteorites; particularly, the type 3 chondrites, because of the importance of the chemical data in their classification.

The bulk chemical analyses of these meteorites

were performed using a modified chemical

method published by Jarosewich (1966). Between 2 and 20 g of sample were made available

for the analyses of these Antarctic meteorites,

but for actual analysis only between 1.5 and 3.5

g was used. Most of the samples were prepared

in a clean environment with a special automatic

Eugene Jarosewich, Department of Mineral Sciences, National

Museum of Natural History, Smithsonian Institution, Washington,

D.C. 20560.

agate mortar, where the whole sample was

ground, homogenized, and then split for other

studies, including those for trace elements.

As a convenient summary of bulk analyses,

Table 10 gives the data for 17 newly analyzed

chondrites and for 8 meteorites published earlier

by Marvin and Mason (1980). The data in this

table give primarily basic geochemical information and indicate the degree of weathering. Six

of the L3 type severely weathered chondrites

(indicated by an asterisk in Table 10) are paired

and their chemical data are given. The chemical

analyses of these L3 types were undertaken before they were identified as paired. The agreement of the data, considering that they were

obtained on different specimens, is remarkable,

although it is somewhat disappointing that these

rare meteorites are paired rather than separate

specimens. All the data of these meteorites for

FeO, Fe-metal, FeS, H2O and C do not give true

values for these components; nevertheless, with

some corrections, the nature of chemical composition of the meteorites can be approximated.

The weathering of the Antarctic meteorites was

described in a general manner by Lipschutz

(1982). Gibson and Andrawes (1980) described

specifics of C and S content and possible condition of weathering processes, and Marvin and

Motylewski (1980) described the mineralogy of

weathered meteorites.

I l l
112 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE 10.—Chemical composition of Antarctic meteorites (nd = not determined; * =

paired L3 meteorites; H2O = H2O total; Fe,M = Fe-metal; Fe,T = Fe total)

Name and type

ALHA77003

ALHA77005

*ALHA77O11

*ALHA77015

ALHA77155

*ALHA77167

*ALHA77214

ALHA77216

ALHA77219

ALHA77231

*ALHA77249

ALHA77256

ALHA77257

•ALHA77260

ALHA77270

ALHA77271

ALHA77278

ALHA77284

ALHA77294

ALHA77296

ALHA77297

ALHA77299

ALHA77304

ALHA77078

ALHA78106

C3

Sh

L3

L3

L6

L3

L3

L3

M

L6

L3

Di

Ur

L3

L6

H6

LL3

L6

H5

L6

L6

H3

L4

L6

L6

SiO2

34.19

42.40

38.21

38.23

39.99

37.94

37.73

39.43

32.27

39.43

36.96

52.15

41.12

37.53

40.15

36.88

41.03

40.43

37.75

40.21

40.13

35.94

40.49

38.64

39.70

TiO2

0.14

0.46

0.14

0.14

0.13

0.13

0.11

0.10

0.16

0.11

0.12

0.16

0.04

0.13

0.12

0.11

0.12

0.12

0.14

0.14

0.14

0.11

0.14

0.13

0.13

A12O3

2.89

3.14

2.29

2.29

2.21

2.18

2.30

2.25

3.93

2.18

2.21

1.56

<0.1

2.15

2.49

1.97

2.26

2.30

2.31

2.36

2.41

2.27

2.35

2.34

2.36

Cr2O3

0.49

1.05

0.57

0.57

0.54

0.58

0.49

0.49

0.63

0.49

0.53

1.06

0.70

0.56

0.53

0.50

0.50

0.48

0.57

0.57

0.52

0.41

0.57

0.58

0.51

FeO

21.78

19.85

20.07

19.63

16.33

19.64

19.63

15.85

15.84

16.07

21.28

16.07

13.57

21.45

15.46

13.43

16.79

14.50

8.76

15.53

15.43

13.15

16.36

15.57

14.31

MnO

0.31

0.46

0.27

0.26

0.32

0.26

0.33

0.32

0.41

0.31

0.26

0.47

0.38

0.24

0.32

0.28

0.34

0.32

0.33

0.35

0.36

0.30

0.28

0.35

0.36

MgO

23.53

28.16

23.89

23.97

24.70

23.85

22.69

24.57

12.56

24.47

22.91

26.48

39.66

23.82

24.92

23.36

24.08

25.17

23.66

25.00

25.02

22.50

25.10

24.49

25.13

CaO

2.22

3.39

1.78

1.71

1.79

1.64

1.70

1.67

3.14

1.75

1.60

1.50

1.07

1.75

1.79

1.60

1.90

1.78

1.83

1.96

1.93

1.81

1.81

1.86

1.96

Na2O

0.56

0.48

0.92

0.74

0.95

0.91

0.82

0.90

0.15

0.91

0.86

0.04

0.03

0.83

0.96

0.83

0.82

0.91

0.72

0.80

0.80

1.08

1.01

0.74

0.75

K2O

0.06

0.04

0.12

0.10

0.11

0.11

0.07

0.12

0.03

0.12

0.11

0.01

0.01

0.11

0.11

0.10

0.10

0.10

0.07

0.09

0.08

0.12

0.13

0.07

0.07

The degree of weathering in the Antarctic

meteorites is accurately reflected in the preliminary petrographic description of the meteorites

in the NASA Newsletters. Severely weathered meteorites denoted as "C" condition and two "A"

(minor weathering) were selected from Table 10

and are listed in Table 11; in this table the degree

of weathering is quantitatively expressed for

FeO, H2O, FeS, Fe-metal, and C. It can be seen

that the values for H2O, C, and FeO (which

includes weathered metal) are higher and Femetal and FeS are lower than the averages for

their class of meteorites. There are some exceptions to this general trend; FeS in ALHA77214

and C in ALHA77271 are very close to the

average amounts of these two components for

their type, and two meteorites in Table 10,

ALHA77278 and ALHA77299, classified as "A"

(minor weathering) show considerable amounts

of H2O and a slight increase in C, and

ALHA77299 shows high FeO and low Fe-metal.

These few variations in an otherwise definite

trend in weathering of different constituents in

meteorites, high FeO, H2O, C, and low Fe-metal

and FeS, would indicate that the weathering is a

very selective process, one dependent on variety

of conditions, the processes of which are little

understood.

The contamination of the Antarctic meteorites, especially those of "A" condition, at this

point, is not a serious problem for most elements

that have been studied (Lipschutz, 1982). However, it is evident that the carbon contamination

in "C" condition meteorites is significant and its

source is of importance. The suggestion of the

presence of CO2 in secondary minerals was verified, using classical CO2 determination in "C

condition meteorite, ALHA77214 (for which
NUMBER 26 113

TABLE 10.—Continued.

P2O5

0.23

0.41

0.25

0.25

0.20

0.24

0.21

0.20

0.30

0.23

0.24

0.01

0.06

0.27

0.26

0.22

0.20

0.18

0.25

0.22

0.24

0.22

0.22

0.25

0.22

H2O

1.89

0.02

2.74

2.55

0.49

2.74

3.29

0.75

1.63

0.75

3.34

0.02

0.18

2.99

0.31

1.25

1.58

0.79

0.23

0.20

0.14

1.71

0.99

0.71

0.11

Fe,M

4.50

ND

1.94

2.30

6.09

2.44

2.02

6.40

23.63

6.37

2.25

nd

nd

1.53

5.99

12.90

2.23

5.90

16.00

6.00

6.39

12.26

4.36

6.48

6.78

Ni

1.37

0.01

1.02

1.12

1.34

1.13

1.18

1.13

2.86

1.20

1.17

0.01

0.08

1.11

1.12

1.69

1.03

1.20

1.84

1.26

1.11

1.67

1.16

1.32

1.29

Co

0.07

<0.01

0.06

0.06

0.06

0.06

0.06

0.06

0.10

0.06

0.07

<0.01

<0.01

0.06

0.07

0.09

0.05

0.06

0.06

0.06

0.07

0.08

0.07

0.07

0.07

FeS

4.85

<0.1

4.47

4.69

4.32

4.55

5.73

5.75

1.10

4.88

4.41

0.15

<0.01

3.43

5.34

4.42

6.17

5.16

5.62

4.80

5.24

5.23

4.80

6.03

5.87

C

0.28

0.02

0.97

0.98

0.04

0.99

1.08

0.04

0.15

0.03

1.08

0.03

3.34

1.07

0.01

0.04

0.16

0.01

0.02

0.01

0.01

0.38

0.01

0.02

0.01

Total

99.36

99.89

99.71

99.59

99.61

99.36

99.44

100.03

98.89

99.36

99.40

99.72

100.24

99.03

99.95

99.67

99.36

99.41

100.16

99.56

100.02

99.24

99.85

99.65

99.63

Fe,T

24.51

15.43

20.38

20.54

21.53

20.60

20.77

22.37

36.64

21.96

21.59

12.49

10.55

20.39

21.40

26.15

19.20

20.45

26.38

21.12

21.72

25.80

20.13

22.41

21.64

Ref

2

2

1

1

1

1

2

1

2

1

1

2

2

1

1

1

2

1

1

1

1

2

1

1

1

Degree

of

weathering2

A

A

C

C

A /B

C

c

A /B

B

A /B

C

A /B

A

C

A /B

C

A

A /B

A

A /B

A

A

B

A /B

A /B

1

 References: 1 = herein; 2 = Marvin and Mason, 1980, appendix 2.

2

 Degree of weathering: A = minor; B = moderate; C = severe.

TABLE 11.—Amounts of most weathered components of weathered meteorites

(A = minor, C = severe).

Name and type

ALHA77011 L3

ALHA77015 L3

ALHA77167 L3

ALHA77214 L3

ALHA77249 L3

ALHA77260 L3

ALHA77271 H6

ALHA77278 LL3

ALHA77299 H3

FeO

20.07

19.63

19.64

19.63

21.28

21.45

13.43

16.79

13.15

H2O

2.74

2.55

2.74

3.29

3.34

2.99

1.25

1.58

1.71

Fe,M

1.94

2.30

2.44

2.02

2.25

1.53

12.9

2.23

12.26

FeS

4.47

4.69

4.55

5.73

4.41

3.43

4.42

6.17

5.23

C

0.97

0.98

0.99

1.08

1.08

1.07

0.04

0.16

0.39

Degree

of

weathering

C

C

c

c

c

c

c

A

A
114 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

sufficient sample was available), giving 0.19%

CO2, clearly within the range estimated by Gibson and Andrawes (1980) from 5% to 10% of

total carbon but still not accounting for the remainder of carbon.

Weathering is not a major concern in the study

of these meteorites; however, the contamination

or depletion of elements is. The relationship

between weathering, which can be readily observed, and contamination is an area to be explored. This work establishes for a group of

Antarctic meteorites that the presence of H2O

and low Fe-metal with resulting high FeO and

depletion of FeS is accompanied by an increase

of C, which is clearly a contaminant.

The analyses of weathered Antarctic meteorites, especially those of rare types, will be the

source of important additional data, provided

the necessary precautions are exercized in the

acquisitions of these data.

The analyses of carbon in the Antarctic Meteorite samples was done by J. Nelen.

Literature Cited

Gibson, E.K., Jr., and F.F. Andrawes

1980. The Antarctic Environment and Its Effect upon

the Total Carbon and Sulfur Abundances in Recovered Meteorites. In Proceedings of the Eleventh

Lunar and Planetary Science Conference, pages

1223-1234. New York: Pergamon Press.

Jarosewich, E.

1966. Chemical Analyses of Ten Stony Meteorites. Geochimica et Cosmochimica Acta, 30:1261-1265.

Lipschutz, M.E.

1982. Weathering Effects in Antarctic Meteorites. In

U.B. Marvin and B. Mason, editors, Catalog of

Meteorites from Victoria Land, 1978-1980.

Smithsonian Contributions to the Mineral Sciences,

24:67-69.

Marvin, U.B., and B. Mason, editors

1980. Catalog of Antarctic Meteorites, 1977-1978.

Smithsonian Contributions to the Earth Sciences, 23:

50 pages.

Marvin, U.B., and K. Motylewski

1980. Mg-Carbonates and Sulfates on Antarctic Meteorites. Lunar and Planetary Science XI, pages 669-

670. Houston: Lunar and Planetary Institute.
Appendix

Tables of Victoria Land Meteorites

Terminology

Class and type: A = achondrite, unique; Au = aubrite; C = carbonaceous chondrite; Di =

diogenite; E = enstatite chondrite; Eu = eucrite; H = high-iron chondrite; Ho = howardite; I

= iron (IA, IIA, IIB, IVA = iron groups); L = low-iron chondrite; LL = low-iron low-metal

chondrite; M = mesosiderite; Sh = shergottite; Ur = ureilite. Chondrite type is indicated by

the digit following the letter.

Olivine composition in mole percent Fe2SiO4(Fa).

Pyroxene (orthopyroxene or low-Ca clinopyroxene) composition in mole percent FeSiO3(Fs).

Degree of weathering: A = minor; metal flecks have inconspicuous rust halos, oxide stain

along cracks is minor. B = moderate; metal flecks show large rust halos, 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; MBR = Mount Baldr; MET = Meteorite Hills; OTT = Outpost Nunatak;

PCA = Pecora Escarpment; PGP = Purgatory Peak; RKP = Reckling Peak; TIL = Thiel

Mountains.

Classification: by SJ.B. Reed and S.O. Agrell (*); by S.G. McKinley and K. Keil (**).

Abbreviations: n.d. = no data.

NOTE: While this monograph was in press PCA82500 was reclassified from LL6 to C4.

115
116 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

11 LJ.111 UC1

ALHA

76001

76002

76003

76004

76005

76006

76007

76008

76009

77001

77002

77003

77004

77005

77007**

77008**

77009

77010

77011

77012

77013**

77014

77015

77016**

77017**

77018**

77019**

77021

77022**

77023**

77025

77026**

77027**

77029**

77031**

77033

77034**

77036**

77038**

77039**

77041**

77042**

77043**

77045**

77046**

77047**

Weight

(g)

20151

1510

10495

305

1425

1137

410

1150

407000

252

235

779

2230

482

99

93

235

295

291

180

23

308

411

78

77

51

.59

16

16

21

19

20

3

1

0.5

9

1

8

18

8

16

20

11

17

7

20

Class

and

type

L6

I

L6

LL3

Eu

H6

L6

H6

L6

L6

L5

C3

H4

Sh

H5

L6

H4

H4

L3

H5

L3

H5

L3

H5

H5

H5

L6

H5

H5

H5

H5

L6

L6

C3

L3

L3

L3

L3

H5

H5

LL6

H5

L3

H5

H6

L3

%Fain

olivine

25

25

0-34

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.

%Fsin

pyroxene

21

21

0-53

37-57

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.

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

Specimen

ni inn rif*T*

HUH lUv 1

77049**

77050**

77051**

77052**

77054**

77056**

77058**

77060**

77061

77062

77063**

77064

77066**

77069**

77070**

77071

77073**

77074

77076**

77078**

77079**

77081

77082**

77084**

77085**

77086

77087**

77088

77089**

77091**

77092**

77094**

77096**

77098**

77100**

77101**

77102

77104**

77106**

77108**

77111**

77112**

77113**

77114**

77115**

77117**

77118

Weight

(g)

7

84

15

112

10

12

3

64

12

16

2

6

4

0.8

18

10

10

12

1

7

7

8

12

44

45

19

30

51

7

4

45

6

2

8

8

3

12

6

7

0.7

52

21

2

44

154

20

7

Class

and

type

L3

L3

H5

L3

H5

H4

H5

LL5

H5

H5

H5

H5

H5

L6

H5

H5

H5

H5

H5

H5

H5

H?

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

%Fain

olivine

n.d.

n.d.

18.8

n.d.

18.5

18.8

18.8

28.1

18

18

18.0

18

19.0

25.4

18.4

18

18.8

18

19.5

19.5

18.2

11

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

%Fsin

pyroxene

n.d.

n.d.

16.5

n.d.

16.9

16.3

16.1

23.2

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

18.4

17.2

n.d.

21.0

17

Degree

of

weathering

B/C

B/C

A

B/C

B

A/B

B

A

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
NUMBER 26 117

TABLE A.—Continued.

Specimen

n i l t n h/^T"

11 U 111 U\Z1

77119

77120**

77122**

77124

77125**

77126**

77127**

77129**

77130**

77131**

77132**

77133**

77134**

77136**

77138**

77139**

77140

77142**

77143**

77144

77146**

77147**

77148

77149**

77150

77151**

77152**

77153**

77155

77156**

77157**

77158**

77159**

77160

77161**

77162**

77163**

77164

77165

77166**

77167

77168**

77170**

77171**

77173**

77174**

77175**

77176**

77177

Weight

(g)

6

3

4

4

18

25

3

1

24

25

115

18

19

3

2

65

78

3

39

7

18

18

13

25

58

16

17

12

305

17

88

19

17

70

6

29

24

38

30

138

611

24

12

23

25

32

23

54

368

Class

and

type

H5

H5

H5

H5

H5

H5

L5

H5

H5

H6

H5

H6

H6

H5

H5

H5

L3

H5

H5

H6

H6

H6

H6

H6

L6

H5

H5

H5

L6

E4

H6

H5

L6

L3

H5

L6

L3

L3

L3

L3

L3

H5

L3

H5

H5

H5

L3

L3

H5

%Fa in

olivine

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

18.6

8-44

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

3-46

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

%Fs in

pyroxene

17

16.0

16.8

16

15.5

16.2

21.1

16.6

16.5

16.8

16.9

17.0

16.7

16.4

17.0

16.4

2-17

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

Degree

of

weathering

C

A / B

B

C

A/B

A / B

B

B

A

A / B

A / B

A

A

A / B

A

A / B

C

A / B

A / B

B

A / B

A / B

C

A / B

C

A

A

A

A / B

A

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

Specimen

n u m oer

77178**

77180

77181**

77182

77183

77184**

77185**

77186**

77187**

77188**

77190

77191

77192

77193**

77195**

77197**

77198**

77200**

77201**

77202**

77205**

77207**

77208

77209**

77211**

77212**

77213**

77214

77215

77216

77217

77218**

77219

77220**

77221

77222**

77223

77224

77225

77226

77227**

77228**

77230

77231

77232

77233

77235**

77237**

77239**

Weight

(g)

5

190

33

1134

288

127

28

122

52

109

387

642

845

6

4

20

7

0.9

15

2

3

4

1733

31

26

16

8

2111

819

1470

413

45

637

69

229

125

207

786

5878

15323

16

19

2473

9270

6494

4087

4

4

19

Class

and

type

L3

L6

H5

H5

H6

H5

L3

H5

H5

H5

H4

H4

H4

H5

H5

L3

L6

H6

H5

H5

H5

H5

H4

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

%Fa in

olivine

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

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

%Fs in

pyroxene

2-40

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

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

Degree

of

weathering

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

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
118 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

77240**

77241**

77242**

77244**

77245**

77246**

77247**

77248**

77249

77250

77251**

77252

77253**

77254

77255

77256

77257

77258

77259

77260

77261

77262

77263

77264

77265**

77266**

77267**

77268

77269

77270

77271

77272

77273

77274

77275**

77277

77278

77279**

77280

77281

77282

77283

77284

77285

77286

77287

77288

77289

77290

Weight

(g)

25

144

56

39

33

41

44

96

503

10555

68

343

23

245

765

676

1995

597

294

744

411

861

1669

11

18

108

103

272

1045

588

609

674

492

288

24

142

312

174

3226

1231

4127

10510

376

271

245

230

1880

2186

3784

Class

and

type

H5

L3

H5

L3

H5

J6

H5

H6

L3

I

L6

L3

H5

L5

I

Di

Ur

H6

H5

L3

L6

H4

I

H5

H5

H5

L5

H5

L6

L6

H6

L6

L6

H5

H5

L6

LL3

H5

L6

L6

L6

1

L6

H6

H4

H5

H6

I

1

%Fa in

olivine

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

24

18

24

24

18

18.3

24

11-29

18.8

24

24

24

25

18

17

18

19

%Fsin

pyroxene

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

21

16

20

20

16

15.6

20

9-21

17.1

21

20

20

21

16

12-16

16

17

Degree

of

weathering

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

A / B

C

B /C

B

C

A

A / B

A

A

B

B

B

A / B

C

C

C

C

Specimen

nil nvrM^T*

11 It 111 L/C 1

77291**

77292

77293**

77294

77295**

77296

77297

77299

77300

77301**

77302

77303**

77304

77305

77306

77307

78004*

78006

78015*

78019

78027*

78038

78039

78040

78042

78043

78044

78045

78047*

78048

78050

78052*

78053

78074

78075

78076

78077

78078

78081*

78084

78085

78086*

78088*

78090*

78092*

78094*

78096*

78098*

Weight

(g)

5

199

109

1351

141

963

951

260

234

55

235

78

650

6444

19

181

35

8

34

30

29

363

299

211

214

680

164

396

130

190

1045

97

179

200

280

275

330

290

17

14280

219

9

5

7

16

4

7

2

Class

and

type

H5

L6

L6

H5

E4

L6

L6

H3

H5

L6

Eu

L3

L4

L6

C2

C3

H5

Ho

LL(?L)3

Ur

H5

L3

L6

Eu

L6

L6

L4

L6

H5

L6

L6

H5

H4

L6

H5

H6

H4

L6

H5

H4

H5

H6

H5

H5

H5

H5

H5

H5

%Fa in

olivine

18.9

24

24.7

17

0.8

24

24

11-21

18

24.9

n.d.

18-27

24

1-45

1-30

19.2

8-35

22

19.3

4-42

24

24

25

23-25

25

18.8

24

23

17.9

17

24

18

18

19

24

19.1

18

18

19.0

18.8

18.7

19.0

19.1

18.9

18.9

%Fsin

Degree

of

pyroxene weathering

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

25-61

18

2-19

21

33-52

20

21

19-24

21

21

20

16

21

16

16

15-18

20

8-24

16

A

B

B

A

B

A / B

A

A

C

A

A

B/C

B

B /C

A

A

A

B/C

C

B

A

B

B

B /C

B /C

B

A/B

B

C

C

B

B /C

B

C

A / B

B /C

B
NUMBER 26 119

TABLE A.—Continued.

Specimen

number

78100

78102

78103

78104

78105

78106

78107

78108

78109

78110

78111

78112

78113

78114

78115

78116*

78121*

78125*

78126

78127

78128

78130

78131

78132

78134

78135*

78139*

78142*

78147*

78153

78158

78160*

78165

78188

78193

78196

78209

78211

78213

78215

78221

78223

78225

78227

78229

78231

78233

78251

78252

Weight

(g)

85

336

589

672

941

464

198

172

233

160

126

2485

298

808

847

127

30

18

606

194

154

2733

268

656

458

130

17

31

30

151

15

16

20

0.9

13

11

12

11

9

6

5

6

4

2

1

1

1

1312

2789

Class

and

type

I

H5

L6

L6

L6

L6

H5

H5

LL5

H5

H5

L6

Au

L6

H6

H5

H5

L6

L6

L6

H5

L6

L6

Eu

H4

H6

H5

L5

H5,6

LL6

Eu

H5

Eu

L3

H4

H4

H5

H6

H6

H6

H5

H4

H5

H5

H6

H6

H5

L6

I

%Fain

olivine

18

24

24

23

24

18

18

28

18

18

25

0

25

18

18.7

19.2

25.0

25

24

19

25

25

18

19.0

19.3

24.2

19.4

29

19.3

1-34

18

18

18

18

18

18

18

18

18

18

18

18

18

23

%Fs in

pyroxene

17

20

20

20

20

17

16

23

16

16

20

0

20

16

21

20

17

21

21

40-68

15-20

24

40-68

37-61

5-29

16

16

15

16

15

16

16

16

16

16

15

16

16

20

Degree

of

weathering

B/C

B

B

B

A/B

C

B

A/B

B/C

B/C

B

A/B

B/C

B

B

B

B

B/C

C

B/C

B/C

A

B/C

B

B/C

A

A

C

B/C

B/C

B/C

B

B

B/C

B

B

B

B/C

B

B/C

B/C

B

Specimen

m irnHpr i luin u \ ~ i

78261

78262

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

Weight

(g)

5

26

32

222

5

34

60

40

142

12

75

25

14

191

28

10

64

1146

310

120

12

4

29

31

68

21

1208

572

133

16

505

2

2

208

12

37

20

14

49

108

13

20

11

62

115

89

19

36

Class

and

type

C2

Ur

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

% Fa in

olivine

0-50

22

6-39

16

10-38

16

18

18

23

17

18

17

18

17

18

18

17

17

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

%Fs in

pyroxene

1-8

19

2-31

18

5-26

14

16

15

19

15

15

15

16

15

16

16

15

15

28-53

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

Degree

of

weathering

A

B/C

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
120 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

79049

79050

79051

79052

79053

79054

79055

80101

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

Weight

(g)

54

27

24

22

86

36

15

8725

471

535

882

445

432

177

124

167

42

330

312

232

306

191

89

2

33

60

39

49

27

11

139

34

47

138

93

5

19

152

3

52

14

10

4

31

254

163

43

229

Class

and

type

H6

H5

H5

L6

H5

H5

H6

L6

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

C3

C2

A

Eu

Eu

Eu

Eu

%Fa in

olivine

18

18

18

23

17

18

18

24

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

%Fsin

pyroxene

16

15

15

20

15

16

16

20

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

Degree

of

weathering

C

C

c

B /C

B /C

B

B/C

B

A

B

B

C

B

B

B

B

B

B

B

B/C

B

u

MJ

B

B

B /C

B /C

c

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

Specimen

n I i m r^f*T

1 IUI1I U\~. 1

81010

81011

81012

81013

81014

81015

81016

81017

81018

81019

81020

81021

81022

81023

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

Weight

(g)

219

405

36

17727

188

5489

3850

1434

2236

1051

1352

695

912

418

797

379

515

3835

80

153

1851

1594

726

252

254

256

252

320

229

205

194

728

534

106

386

90

16

81

190

8

25

43

28

2

2

4

1

8

66

Class

and

type

Eu

Eu

Eu

I

I

H5

L6

L5

L5

H5

H5

E6

H4

L5

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

%Fain

olivine

19

25

25

24

19

19

19

25

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

%Fs in

pyroxene

31-57

33-60

33-62

16

21

21

21

16

16

0-1

17

21

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

1-42

17

16

17

13-21

15

Degree

of

weathering

A

A / B

A/B

B

B

B

B

B/C

B

A

B/C

B

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
NUMBER 26 121

TABLE A.—Continued.

Specimen

number

81059

81060

81061

81062

81063

81064

81065

81066

81067

81068

81069

81070

81071

81072

81073

81074

81075

81076

81077

81078

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

Weight

(g)

539

28

23

0.5

4

191

13

8

227

23

7

3

2

3

3

7

15

10

4

5

7

16

5

5

6

15

16

5

8

3

11

9

12

15

271

152

58

83

79

70

151

154

119

196

136

183

92

48

139

Class

and

type

M

L3

L3

H5

H5

H5

L3

L3

H5

H4

L3

H5

H5

H5

H4

H4

H5

H6

H5

H6

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

%Fain

olivine

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

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

%Fsin

pyroxene

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

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

Degree

of

weathering

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

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

Specimen

number

81108

81109

81110

81111

81112

81113

81114

81115

81116

81117

81118

81119

81120

81121

81122

81123

81124

81125

81126

81127

81136

81153

81154

81158

81251

82100

82101

BTNA

78001

78002

78004

DRPA

78001

78002

78003

78004

78005

78006

78007

78008

78009

EETA

79001

79002

79003

79004

79005

Weight

(g)

69

1

3

210

150

111

79

154

1

32

84

107

13

88

20

2

9

10

21

15

1

4

1

2

158

24

29

160

4301

1079

15200

7188

144

133

18600

389

11800

59400

138100

7942

2843

435

390

450

Class

and

type

H5

H4

H5

H6

H6

H5

H4

H5

H5

H4

H5

L4

H5

L3

L6

LL6

H5

H5

H5

H6

H5

L5

H6

H5

LL3

C2

C3

L6

L6

LL6

I

I

I

I

I

I

I

I

I

Sh

Di

L6

Eu

Eu

%Fain

olivine

18

19

19

19

19

18

18

19

19

18

19

24

18

8-40

25

30

19

19

19

19

20

24

19

19

1-29

1-47

1-50

24

24

30

23-27

24-25

24

%Fsin

pyroxene

16

17

17

17

17

16

16

17

17

14-21

16

21

16

1-24

21

25

17

17

16

17

17

21

17

17

2-28

1-2

1-10

21

20

24

16-67

22

20

30-61

30-61

Degree

of

weathering

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

B

B

B/C

B/C

A

A

B

B

B

A

B

B

B

A
122 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE A.—Continued.

Specimen

number

79006

79007

79009

79010

79011

82600

MBRA

76001

76002

META

78001

78002

78003

78005

78006

78007

78010

78028

OTTA

80301

PCA

82500

82501

82502

PGPA

77006

RKPA

78001

78002

78003

78004

79001

79002

79003

79004

79008

79009

79012

79013

79014

79015

80201

80202

80203

Weight

(g)

716

199

140

287

86

247

4108

13773

624

542

1726

172

409

174

233

20657

35

90

54

890

19068

234

8483

1276

166

3006

203

182

370

73

55

12

11

77

10022

813

544

3

Class

and

type

Ho

H5

L5

L6

Eu

Ho

H6

H6

H4

L6

L6

L6

H6

H6

H5

L6

H3

LL6

Eu

Eu

I

L6

H4

L6

H4

L6

L6

H6

H5

L3

H6

H6

L5

H5

M

H6

L6

H6

%Fa in

olivine

18

24

24

18

18

17

23

24

24

18

19

19

25

17-19

31

23

18

23

17

23

24

18

18

1-29

18

18

23

18

19

24

19

%Fsin

pyroxene

19-57

16

20

20

30-61

22-53

16

16

14-21

20

21

20

15

17

17

21

4-19

41-57

36-61

20

15

20

14-21

20

20

16

16

2-28

16

16

20

16

24

16

20

17

Degree

of

weathering

B

B

B

B

B

A

B

B

B /C

B

B

B

C

B /C

B

B

B

B

A

A

C

B

C

A

B

B

B

B /C

B

C

B

B /C

B /C

A / B

B

B

C

Specimen

number

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

80233

80234

80235

80236

80237

80238

80239

80240

80241

80242

80243

80244

80245

80246

80247

80248

80249

80250

80251

80252

80253

Weight

(g)

15

53

46

17

10

9

10

2

19

4

9

44

7

6

21

124

51

6

25

8

8

160

7

11

14

58

238

80

413

136

261

15

22

18

5

61

0.6

7

3

14

36

5

1

11

9

3

29

11

4

Class

and

type

Eu

H3

H6

H3

H6

L5

H5

H6

H6

H6

L6

L4

H5

H5

L6

H5

H6

LL6

H5

Eu

L6

I

H5

L5

M

H5

H6

H4

H5

LL5

LL6

H5

H4

LL6

Ur

H5

C3

L4

H5

H5

H5

M

H5

LL6

H5

H5

H5

L6

LL5

%Fa in

olivine

17-20

19

15-29

19

25

19

19

19

19

24

23

18

18

25

18

19

28

18

25

19

23

18

18

18

18

26

30

18

18

28

16

18

1-6

22

18

18

18

18

27

17

17

17

24

27

%Fs in

pyroxene

52-57

5-13

17

6-28

17

21

16

17

17

17

20

20

15

15

21

16

17

23

16

54

21

16

19

24

16

16

16

16

22

24

16

16

23

15

16

1-8

19

16

16

16

24

16

23

15

15

15

20

22

Degree

of

weathering

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

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
NUMBER 26 123

TABLE A.—Continued.

Specimen

number

80254

80255

80256

80257

80258

80259

80260

80261

80262

Weight

(g)

68

6

153

8

4

20

7

61

32

Class

and

type

H6

H6

L3

H5

M

E5

H5

L6

H6

%Fain

olivine

19

19

20-25

17

18

24

19

%Fsin

pyroxene

17

17

10-26

15

17-21

0-1

16

20

17

Degree

of

weathering

C

C

B

B/C

B/C

B/C

C

B

C

Specimen

n il m Y^f* T*

11U111 U\Z 1

80263

80264

80265

80266

80267

80268

TIL

82403

Weight

(g)

16

23

7

9

24

3

49

Class

and

type

M

L6

H6

H6

H4

L5

Eu

%Fain

olivine

24

19

19

19

24

%Fsin

Degree

of

pyroxene weathering

24

20

17

17

16

20

43-58

C

B

C

B/C

C

B/C

A
124 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Meteorites listed by class and source area in numerical sequence

(fractions of grams weight dropped unless total weight is less than 1 gram).

Specimen

number

ALHA77306

ALHA78261

ALHA81002

ALHA81004

ALHA82100

ALHA77307

ALHA77003

ALHA77029**

ALHA82101

ALHA81003

RKPA80241

ALHA77156**

ALHA77295

RKPA80259

ALHA81021

ALHA77299

OTTA80301

RKPA80205

ALHA77004

ALHA77009

ALHA77O1O

ALHA77056**

ALHA77190

ALHA77191

ALHA77192

ALHA77208

ALHA77221

ALHA77222**

ALHA77223

ALHA77224

ALHA77225

ALHA77226

ALHA77232

ALHA77233

ALHA77262

ALHA77286

ALHA78053

ALHA78077

ALHA78084

ALHA78134

ALHA78193

ALHA78196 ,

ALHA78223

Weight

(g)

19

5

14

4

24

181

779

1

29

10

0.6

17

141

20

695

260

35

53

2230

235

295

12

387

642

845

1733

229

125

207

786

5878

15323

6494

4087

861

245

179

330

14280

458

13

11

6

Class

and

type

C2

C2

C2

C2

C2

C3

C3

C3

C3

C3

C3

E4

E4

E5

E6

H3

H3

H3

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

A

A

A/B

A

A

A

A/B

A

A/B

B

B

B

B/C

A

A

B/C

B

C

C

C

A/B

C

C

c

c

c

A/B

C

c

c

c

c

c

B/C

c

c

c

B/C

B/C

B/C

B/C

B

Degree of fracturing

CHON

A

A

B

A

A

A

A

A/B

A/B

B

B

B

A

B

B

C

A

A

C

B/C

C

C

A

C

C

c

c

c

B

B

B

B

B

B

B/C

A

B

B

Specimen

number

DRrTES

ALHA79023

ALHA79035

ALHA79039

ALHA80106

ALHA80121

ALHA80128

ALHA80131

ALHA81022

ALHA81041

ALHA81043

ALHA81044

ALHA81045

ALHA81046

ALHA81047

ALHA81048

ALHA81049

ALHA81050

ALHA81051

ALHA81052

ALHA81056

ALHA81057

ALHA81058

ALHA81068

ALHA81073

ALHA81074

ALHA81092

ALHA81095

ALHA81097

ALHA81104

ALHA81105

ALHA81109

ALHA81114

ALHA81117

META78001

RKPA78002

RKPA78004

RKPA80232

RKPA80237

RKPA80267

ALHA79004

ALHA77OO7**

ALHA77012

ALHA77014

ALHA77016**

ALHA77017**

Weight

(g)

68

37

108

432

39

138

19

912

728

106

386

90

16

81

190

8

25

43

28

1

8

66

23

3

7

15

58

79

183

92

1

79

32

624

8483

166

80

22

24

34

99

180

308

78

77

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

H5

H5

H5

H5

H5

H5

Degree of weathering

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

B

C

C

B

B/C

B

B/C

B

A

B

C

C

B/C

B

C

C

B

B

Degree of fracturing

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

A

C

B/C

A

B/C

B/C

B

A/B

A

A

B

A

B

A

B/C
NUMBER 26 125

TABLE B.—Continued

Specimen

number

ALHA77018**

ALHA77021

ALHA77022**

ALHA77O23**

ALHA77025

ALHA77038**

ALHA77039**

ALHA77042**

ALHA77045**

ALHA77051**

ALHA77054**

ALHA77058**

ALHA77061

ALHA77062

ALHA77063**

ALHA77064

ALHA77066**

ALHA77070**

ALHA77071

ALHA77073**

ALHA77074

ALHA77076**

ALHA77078**

ALHA77079**

ALHA77082**

ALHA77084**

ALHA77085**

ALHA77086

ALHA77087**

ALHA77088

ALHA77091**

ALHA77092**

ALHA77094**

ALHA77096**

ALHA77098**

ALHA77100**

ALHA771O1**

ALHA77102

ALHA77104**

ALHA77106**

ALHA77108**

ALHA77112**

ALHA77113**

ALHA77114**

ALHA77118

ALHA77119

ALHA77120**

ALHA77122**

Weight

(g)

51

16

16

21

19

18

8

20

17

15

10

3

12

16

2

6

4

18

10

10

12

1

7

7

12

44

45

19

30

51

4

45

6

2

8

8

3

12

6

7

0.7

21

2

44

7

6

3

4

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

i*- be Degree o weatherin

B/C

C

A

B

C

A/B

A/B

A/B

A

A

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

Degree o

fracturinj

A

B

A

B

B

B

B

B

B

B

B

B

Specimen

number

ALHA77124

ALHA77125**

ALHA77126**

ALHA77129**

ALHA77130**

ALHA77132**

ALHA77136**

ALHA77138**

ALHA77139**

ALHA77142**

ALHA77143**

ALHA77151**

ALHA77152**

ALHA77153**

ALHA77158**

ALHA77161**

ALHA77168**

ALHA77171**

ALHA77173**

ALHA77174**

ALHA77177

ALHA77181**

ALHA77182

ALHA77184**

ALHA77186**

ALHA77187**

ALHA77188**

ALHA77193**

ALHA77195**

ALHA77201**

ALHA77202**

ALHA772O5**

ALHA77207**

ALHA77213**

ALHA77220**

ALHA77227**1

ALHA77228**

ALHA77235**

ALHA77237**

ALHA77240**

ALHA77242**

ALHA77245**

ALHA77247**

ALHA77253**

ALHA77259

ALHA77264

ALHA77265**

ALHA77266**

Weight

(g)

4

18

25

1

24

115

3

2

65

3

39

16

17

12

19

6

24

23

25

32

368

33

1134

127

122

52

109

6

4

15

2

3

4

8

69

16

19

4

4

25

56

33

44

23

294

11

18

108

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

i*- bo Degree o weatherin

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

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

Degree o

fracturinj

A

A

B

B

A
126 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued

Specimen

number

ALHA77268

ALHA77274

ALHA77275**

ALHA77279**

ALHA77287

ALHA77291**

ALHA77294

ALHA773OO

ALHA78004*

ALHA78027*

ALHA78047*

ALHA78052*

ALHA78075

ALHA78081*

ALHA78085

ALHA78088*

ALHA78090*

ALHA78092*

ALHA78094*

ALHA78096*

ALHA78098*

ALHA78102

ALHA78107

ALHA78108

ALHA78110

ALHA78111

ALHA78116*

ALHA78121*

ALHA78128

ALHA78139*

ALHA78160*

ALHA78209

ALHA78221

ALHA78225

ALHA78227

ALHA78233

ALHA79006

ALHA79008

ALHA79009

ALHA79010

ALHA79011

ALHA79012

ALHA79013

ALHA79014

ALHA79015

ALHA79021

ALHA79025

ALHA79026

Weight

(g)

272

288

24

174

230

5

1351

234

35

29

130

97

280

17

219

5

7

16

4

7

2

336

198

172

160

126

127

30

154

17

16

12

5

4

2

1

40

12

75

25

14

191

28

10

64

29

1208

572

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

t4_, be gree o itheriri

Q %

C

C

A

A

C

A

A

C

B

C

B/C

B

B/C

C

B

B/C

B/C

B

C

B/C

B

B

B/C

B/C

B/C

B

C

B/C

B/C

C

C

B

B

B

C

B

<*- bo

0 g

E 3

b<ue <j a

C

A

A

A

B

B

B

B

B

B

A

B

B

A

B

B/C

B

A

A

B

B

B

B

A

B

A

B

B

A

B

A

A

B

Specimen

number

ALHA79029

ALHA79031

ALHA79032

ALHA79036

ALHA79038

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

ALHA81081

ALHA81082

ALHA81083

ALHA81084

ALHA81088

ALHA81089

ALHA81090

ALHA81091

ALHA81100

Weight

(g)

505

2

2

20

49

13

20

11

89

19

36

27

24

86

36

42

27

11

47

93

152

5489

1051

1352

252

254

252

205

534

0.5

4

191

227

3

2

3

15

4

16

5

5

6

15

3

11

9

12

154

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

u- be

0 _C

u 'C

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

<*f bo gree o cturin

v a

Qi

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
NUMBER 26 127

TABLE B.—Continued

Specimen

number

ALHA81108

ALHA81110

ALHA81113

ALHA81115

ALHA81116

ALHA81118

ALHA81120

ALHA81124

ALHA81125

ALHA81126

ALHA81136

ALHA81158

EETA79007

META78010

RKPA79004

RKPA79014

RKPA80210

RKPA80217

RKPA80218

RKPA80220

RKPA80223

RKPA80227

RKPA80230

RKPA80233

RKPA80236

RKPA80240

RKPA80243

RKPA80244

RKPA80245

RKPA80247

RKPA80249

RKPA80250

RKPA80251

RKPA80257

RKPA80260

ALHA78147*

ALHA76006

ALHA76008

ALHA77046**

ALHA77111**

ALHA77131**

ALHA77133**

ALHA77134**

ALHA77144

ALHA77146**

ALHA77147**

ALHA77148

Weight

(g)

69

3

111

154

1

84

13

9

10

21

1

2

199

233

370

77

10

7

6

124

25

7

58

413

15

61

3

14

36

1

9

3

29

8

7

30

1137

1150

7

52

25

18

19

7

18

18

13

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, 6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

H6

u- be Degree o weatherin

B

B/C

B/C

C

B

B/C

B/C

B

B

B

B

B/C

B

B

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

C

B/C

A/B

A/B

A/B

A

A

B

A/B

A/B

C

Degree o

fracturinj

B

A

C

A/B

A

A

B

A

A

A

A/B

A

B

A

B

B

B

A

A

B/C

B

A

B

B

B

A

A

B

B

B

A

A

B

B

B

B

B

A

B

Specimen

number

ALHA77149**

ALHA77157**

ALHA77183

ALHA77200**

ALHA77209**

ALHA77212**

ALHA77239**

ALHA77246**

ALHA77248**

ALHA77258

ALHA77271

ALHA77285

ALHA77288

ALHA78076

ALHA78086*

ALHA78115

ALHA78135*

ALHA78211

ALHA78213

ALHA78215

ALHA78229

ALHA78231

ALHA79002

ALHA79005

ALHA79016

ALHA79019

ALHA79020

ALHA79024

ALHA79028

ALHA79034

ALHA79037

ALHA79049

ALHA79055

ALHA80118

ALHA80122

ALHA80126

ALHA80130

ALHA81035

ALHA81037

ALHA81038

ALHA81054

ALHA81055

ALHA81076

ALHA81078

ALHA81079

ALHA81086

ALHA81093

ALHA81094

Weight

(g)

25

88

288

0.9

31

16

19

41

96

597

609

271

1880

275

9

847

130

11

9

6

1

1

222

60

1146

12

4

21

16

12

14

54

15

2

49

34

5

256

320

229

2

4

10

5

7

5

271

152

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

tw bo Degree o weatherin

A/B

A/B

C

C

B

A/B

B

B

B/C

B/C

C

C

C

B

B

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

4- be Degree o fracturin

A

A/B

A

B

B

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
128 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued

Specimen

number

ALHA81096

ALHA81102

ALHA81103

ALHA81111

ALHA81112

ALHA81127

ALHA81154

MBRA76001

MBRA76002

META78006

META78007

RKPA79003

RKPA79009

RKPA79012

RKPA80201

RKPA80203

RKPA80206

RKPA80208

RKPA80211

RKPA80213

RKPA80214

RKPA80221

RKPA80231

RKPA80254

RKPA80255

RKPA80262

RKPA80265

RKPA80266

ALHA77081

ALHA/7011

ALHA77013**

ALHA77015

ALHA77031**

ALHA77033

ALHA77034**

ALHA77036**

ALHA77043**

ALHA77047**

ALHA77049**

ALHA77050**

ALHA77052**

ALHA77115**

ALHA77140

ALHA77160

ALHA77163**

ALHA77164

ALHA77165

Weight

(g)

83

196

136

210

150

15

1

4108

13773

409

174

182

55

12

813

3

46

10

2

19

4

51

238

68

6

32

7

9

8

291

23

411

0.5

9

1

8

11

20

7

84

112

154

78

70

24

38

30

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

H?

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

L3

Degree of

weathering

B

B /C

B /C

B /C

B /C

B /C

B

B

B

C

B /C

B

C

B

B

C

C

B

C

B /C

C

C

C

C

C

C

C

B /C

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

Degree of

fracturing

B

A / B

B /C

B

A

B

B

B

B

B

B

A

B

B

A

A

B

A

B

B

B

B /C

B /C

B /C

B

B

B

B

A

A

B

B

B

B

C

C

Specimen

number

ALHA77166**

ALHA77167

ALHA7717O**

ALHA77175**

ALHA77176**

ALHA77178**

ALHA77185**

ALHA77197**

ALHA77211**

ALHA77214

ALHA77215

ALHA77216

ALHA77217

ALHA77241**

ALHA77244**

ALHA77249

ALHA77252

ALHA77260

ALHA77303**

ALHA78038

ALHA78188

ALHA79001

ALHA79045

ALHA80133

ALHA81024

ALHA81025

ALHA81030

ALHA81031

ALHA81032

ALHA81053

ALHA81060

ALHA81061

ALHA81065

ALHA81066

ALHA81069

ALHA81085

ALHA81087

ALHA81121

RKPA79008

RKPA80207

RKPA80256

ALHA79022

ALHA77230

ALHA77304

ALHA78044

ALHA81040

ALHA81119

Weight

(g)

138

611

12

23

54

5

28

20

26

2111

819

1470

413

144

39

503

343

744

78

363

0.9

32

115

3

797

379

1851

1594

726

2

28

23

13

8

7

16

8

88

73

17

153

31

2473

650

164

194

107

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

L3

L3

L3,4

L4

L4

L4

L4

L4

Degree of weathering

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

C

C

C

C

B

C

C

B /C

C

C

C

C

B /C

B /C

C

B /C

C

B /C

B

B

C

B

A/B

C

B

B / C

B /C

B

Degree of fracturing

B /C

C

B /C

B /C

B /C

C

C

C

C

B

A

B

B

B

B

B /C

B /C

A

B

B

A

B

B

A

B

B

B

B

B

A

B

B

B

B

A

B
NUMBER 2

6 12

9

TABLE B.—Continued

Specimen

number

RKPA80216

RKPA80242

ALHA77002

ALHA77117**

ALHA77127**

ALHA77218**

ALHA77254

ALHA77267**

ALHA78142**

ALHA81017

ALHA81018

ALHA81023

ALHA81153

EETA79009

RKPA79013

RKPA80209

RKPA80228

RKPA80268

ALHA76001

ALHA76003

ALHA76OO7

ALHA76009

ALHA77001

ALHA77008**

ALHA77019**

ALHA77026**

ALHA77027**

ALHA77069**

ALHA77089**

ALHA77150

ALHA77155

ALHA77159**

ALHA77162**

ALHA77180

ALHA77198**

ALHA77231

ALHA77251**

ALHA77261

ALHA77269

ALHA77270

ALHA77272

ALHA77273

ALHA77277

ALHA77280

ALHA77281

ALHA77282

ALHA77284

Weight

(g)

447

235

203

45

245

103

31

1434

2236

4184

140

119

113

20151

10495

410

407000

252

93

59

203

0.8

7

58

305

17

29

1907

9270

68

411

1045

588

674

492

142

3226

1231

4127

376

Class

and

type

L4

L4

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

tw be

Degree o

weatherin

B

B/C

B

A/B

BA

A/B

ABBBBB

B/C

CC

B/C

AABBBA

B/C

B/C

B/C

B/C

BC

A/B

A/B

ACB

A/B

BBB

A/B

B/C

B

A/B

BBB

A/B

Degree o

fracturinj

BB

A/B

AAB

A/B

ABBBBBAAABBBAA

A/B

BABBBA

B/C

BBB

Specimen

number

ALHA77292

ALHA77293**

ALHA77296

ALHA77297

ALHA77301**

ALHA77305

ALHA78039

ALHA78042

ALHA78043

ALHA78045

ALHA78048

ALHA78050

ALHA78074

ALHA78078

ALHA78103

ALHA78104

ALHA78105

ALHA78106

ALHA78112

ALHA78114

ALHA78125*

ALHA78126

ALHA78127

ALHA78130

ALHA78131

ALHA78251

ALHA79007

ALHA79018

ALHA79027

ALHA79033

ALHA79043

ALHA79052

ALHA80101

ALHA80103

ALHA80105

ALHA80107

ALHA80108

ALHA80110

ALHA80112

ALHA80113

ALHA80114

ALHA80115

ALHA80116

ALHA80117

ALHA80119

ALHA80120

ALHA80125

ALHA81016

Weight

(g)

199

109

963

951

55

6444

299

214

680

396

190

1045

200

290

589

672

941

464

2485

808

18

606

194

2733

268

1312

142

120

133

208

62

22

8725

535

445

177

124

167

330

312

232

306

191

89

33

60

139

3850

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

IH be

Degree o weatherin BB

A/B

AA

B/C

BBB

B/C

A/B

BB

A/B

BBB

A/B

B

B/C

BB

B/C

B/C

B/C

B

A/B

B/C

BBC

B/C

BBBBBBBBBB

B/C

BBB

B/C

B

Degree o

fracturin|

AABBBABBBBBABAAABBBBBBAAB

A/B

AABBBABBBBB

B/C

BABABBBA
130 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued

Specimen

number

ALHA81026

ALHA81027

ALHA81028

ALHA81029

ALHA81099

ALHA81106

ALHA81107

ALHA81122

BTNA78001

BTNA78002

EETA79003

EETA79010

META78002

META78003

META78005

META78028

RKPA78001

RKPA78003

RKPA79001

RKPA79002

RKPA80202

RKPA80215

RKPA80219

Weight

(g)

515

3835

80

153

151

48

139

20

160

4301

435

287

542

1726

172

20657

234

1276

3006

203

544

9

21

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

Degree of weathering

B

C

B

C

A / B

B

B

B

B

B

B

B

B

B

B

B

C

C

B

B

B

C

B

Degree of

fracturing

A

A / B

B

A

A

B

A

B

B

A

B

C

A

B

B

B

B

B

C

B

A

B

A

Specimen

number

RKPA80225

RKPA80252

RKPA80261

RKPA80264

ALHA78015*

ALHA76004

ALHA77278

ALHA79003

ALHA81251

ALHA77060**

ALHA78109

RKPA80234

RKPA80253

ALHA77041**

ALHA78153

ALHA81123

BTNA78004

PCA82500

RKPA80222

RKPA80235

RKPA80238

RKPA80248

Weight

(g)

8

11

61

23

34

305

312

5

158

64

233

136

4

16

151

2

1079

90

6

261

18

11

Class

and

type

L6

L6

L6

L6

LL(?L)3

LL3

LL3

LL3

LL3

LL5

LL5

LL5

LL5

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

LL6

Degree of weathering

C

A / B

B

B

A

A

B

B /C

A

A / B

B

A / B

A

B /C

B

B

B

B

A/B

A /B

A / B

Degree of fracturing

A

A

A

B

A

A

B

B

A

B

A

B

A

A

C

B

B

A

A

Subtotals:

Total:

Class and type

C2

C3

E5

E6

E4

H3

H4

H5

H5,6

H6

H?

L3

L3,4

L4

L5

L6

LL(L)3

LL3

LL5

LL6

Class 'weight (g)

66

1000

20

695

158

348

69549

25301

30

31453

8

20667

31

3637

5385

53889

34

780

437

1634

215122
NUMBER 26 131

TABLE B.—Continued

Specimen

number

ALHA81005

ALHA78113

ALHA77256

EETA79002

ALHA76005

ALHA77302

ALHA78040

ALHA78132

ALHA78158

ALHA78165

ALHA79017

ALHA80102

ALHA81001

ALHA81006

ALHA81007

ALHA81008

ALHA81009

ALHA81010

ALHA81011

Weight

(g)

31

298

676

2843

1425

235

211

656

15

20

310

471

52

254

163

43

229

219

405

Class

and

type

Anorthositic

breccia

Au

Di

Di

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu (anomalous)

Eu (polymict)

Eu (polymict)

Eu (polymict)

Eu

Eu (polymict)

Eucritic breccia

(*. bo Degree o weatherin

A/B

A/B

A/B

B

A

A

A

A

A

A

A

A

A

A

A/B

A/B

A

A

A/B

UH he Degree o fracturinj

Specimen

number

ACHONDRITES

A

A

A

B

A

A

A

A

A

A

A

B

B

A/B

A

A/B

A

A

A

ALHA81012

EETA79004

EETA79005

EETA79011

PCA82501

PCA82502

RKPA80204

RKPA80224

TIL82403

ALHA78006

EETA79006

EETA82600

ALHA77005

EETA79001

ALHA77257

ALHA78019

ALHA78262

ALHA81101

RKPA80239

Weight

(g)

36

390

450

86

54

890

15

8

49

8

716

247

482

7942

1995

30

26

119

5

Class

and

type

Eu

Eu

Eu (polymict)

Eu (polymict)

Eu (unbrecciated)

Eu (unbrecciated)

Eu

Eu (unbrecciated)

Eu (brecciated)

Ho

Ho

Ho

Sh

Sh

Ur

Ur

Ur

Ur

Ur

tw be Degree o weatheriri

A/B

B

A

B

A

A

A

A/B

A

A

B

A

A

A

A

B/C

B/C

A/B

B

<*- he Degree o fracturinj

A

B

B

B

A

A

A

A

A

A

B

B

A

A

B

C

A

B

B

Subtotals:

Total:

Class and type

Anorthositic

breccia

Aubrite

Diogenite

Eucrite

Howardite

Shergottite

Ureilite

Class weight (g)

31

298

3519

6686

971

8424

2175

22104

ALHA81013

ALHA81014

ALHA80104

ALHA77255

ALHA76002

17727 Hexahedrite

188 Octahedrite

882 Ataxite

765 Ataxite (anom)

1510 IA

IRONS

ALHA77250

ALHA77263

ALHA77283

ALHA77289

ALHA77290

10555 IA

1669 IA

10510 IA

2186 IA

3784 IA
132 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE B.—Continued

Specimen

number

PGPA77006

ALHA78100

DRPA78001

DRPA78002

DRPA78003

DRPA78004

DRPA78005

ALHA81098

ALHA77219

ALHA81059

RKPA79015

RKPA80229

Weight

(g)

19068

85

15200

7188

144

133

18600

70

637

539

10022

14

Class

and

type

IA

IIA

IIB

IIB

IIB

IIB

IIB

M

M

M

M

M

IH bo Degree o weatherin

C

B

C

A/B

C

<+* ho Degree o fracturini

Specimen

number

DRPA78006

DRPA78007

DRPA78OO8

DRPA78009

ALHA78252

RKPA80226

Total:

STONY-IRONS

B/C

B

B/C

A

B/C

RKPA80246

RKPA80258

RKPA80263

Total:

Weight

(g)

389

11800

59400

138100

2789

160

322832

5

4

16

11307

Class

and

type

IIB

IIB

IIB

IIB

IVA

Octahedrite

M

M

M

<+. b e Degree o weatherin

C

B/C

C

Degree o fracturinj

C

B

B
NUMBER 26 133

TABLE C.—Meteorites from common falls tentatively identified as paired specimens (t = field

relations; v = physical similarities; w = petrographic similarities; x = metallography; y = bulk

chemistry; z = trace element chemistry).

Pair no. Paired specimens Criteria

EUCRITES

1 ALHA76005, 77302, 78040, 78132, 78158, 78165, 79017, 80102, v, w

81006,81007,81008,81010

2 ALHA81009, 81012 v, w

UREILITES

3 ALHA78019, 78262 v, w

C2 CHONDRITES

4 ALHA77306, 78261,81002, 81004 w

L3 CHONDRITES

5 ALHA77011, 77015, 77031, 77033, 77034, 77036, 77043, 77047, w

77049, 77050, 77052, 77115, 77140, 77160, 77163,77164,77165,

77166, 77167, 77170, 77175, 77178, 77185, 77211, 77214, 77241,

77244, 77249, 77260, 77303, 78038, 78188, 79001, 79045, 80133,

81025, 81030, 81031, 81032, 81053, 81060, 81061, 81065, 81066,

81069,81085,81087,81121

6 ALHA77215, 77216, 77217, 77252 t, v, w

L4 CHONDRITES

7 RKPA80216, 80242 w

L5 CHONDRITES

8 ALHA81017,81018, 81023 w

L6 CHONDRITES

9 ALHA77001, 77150, 77180, 77292, 77293, 77296, 77297, 77305 t, v, w

10 ALHA77231, 77269, 77270, 77272, 77273, 77277, 77280, 77281, t, v, w

77282,77284

11 ALHA78043, 78045 w

12 ALHA78103, 78104, 78105 t, w

13 ALHA78112, 78114 w

14 ALHA78126, 78130, 78131 w

15 ALHA78105, 78251 v

16 ALHA80101, 80103, 80105, 80107, 80108, 80110, 80112, 80113, v, w

80114,80115, 80116, 80117, 80119, 80120, 80125

17 ALHA81027, 81028, 81029 w

18 BTNA78001,78002 v, w

19 RKPA78001, 78003, 79001, 79002, 80202, 80219, 80225, 80252, w

80261,80264

LL3 CHONDRITES

20 ALHA76004,81251 w

LL6 CHONDRITES

21 RKPA80222, 80238, 80248 w
134 SMITHSONIAN CONTRIBUTIONS TO THE EARTH SCIENCES

TABLE C.—Continued

Pair no. Paired specimens Criteria

H4 CHONDRITES

ALHA77004, 77190, 77191, 77192, 77208, 77222, 77223, 77224,

77225,77226,77232,77233

ALHA78084, 81022

ALHA78193, 78196, 78223

ALHA81041, 81043, 81044, 81045, 81046, 81047, 81048, 81049,

81050,81051, 81052

H5 CHONDRITES

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

RKPA80220, 80223

RKPA80250, 80251

H6 CHONDRITES

ALHA77144, 77148

ALHA77271, 77288

ALHA78211, 78213, 78215, 78229, 78231

ALHA80122, 80126, 80130

ALHA81035, 81038, 81103, 81112

RKPA80203, 80206, 80208, 80211, 80213, 80214, 80221, 80231,

80254, 80255, 80262,80265,80266

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

ALHA77156, 77295

E4 CHONDRITES

M ESOSIDERITES

t, w

w

t, X

w

t

t, w

t

t, X

w

w

w

w

w

t

t

t, X

w

w

w

ALHA81059, 81098 w

RKPA79015, 80229, 80246, 80258, 80263 w

IRONS

ALHA76002 , 77250, 77263, 77289, 77290 t, x, y, z

DRPA78001 , 78002, 78003, 78004, 78005, 78006, 78007, 78008, t, v, x, y

78009