U.S. Geological Survey Polar Research SymposiumAbstracts with Program 

GEOLOGICAL SURVEY CIRCULAR 911 

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In celebration of the 1 OOth anniversary of the 

First International Polar Year, the 50th 

anniversary of the Second International 

Polar Year, and the 25th anniversary of 

the International Geophysical Year 

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The U.S. Geological Survey Polar Research Symposium celebrates the lOOth 

and 50th anniversaries of the First and Second International Polar Years, 

respectively, and the 25th anniversary of the International Geophysical Year. 

The symposium is part of a series of worldwide activities that include lectures, 

symposia, and exhibits organized at the request of the International Council of 

Scientific Unions. The International Polar Years and especially the International Geophysical Year profoundly influenced the evolution of geophysics and 

served as models for international multidisciplinary cooperation in science. 
U.S. Geological Survey Polar Research SymposiumAbstracts with Program 

GEOLOGICAL SURVEY 

In celebration of the 1 DOth anniversary of the 

First International Polar Year, the 50th 

anniversary of the Second International 

Polar Year, and the 25th anniversary of 

the International Geophysical Year 

CIRCULAR 

October 12-14, 1983 

9 1 1 
United States Department of the Interior 

JAMES G. WATT, Secretary 

Geological Survey 

Dallas L. Peck, Director 

Free on application to Distribution Branch, Text Products Section, 

U. S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Page 

FTogram-------------------------------------------------------------------- IV 

Ineroduction ---------------------------------------------------------------- 1 

Antarctic program ------------------------------------------------------------ 1 

~c program -----~-------------------------------------------------------- 22 

Abstracts not presented at the symposium ----------------------------------------- 52 

III 
PROGRAM 

October 12, 1983 

Introduction 

8:30 ---- Welcoming Comments- F. Press 

8:35 ---- Introduction to Symposium- D.L. Peck 

8:40 ---- Arctic Research Policy Legislation - Honorable 

F.W. Murkowski 

9:00 ---- The Geological Survey in Polar Perspective - J .C. 

Reed, Sr. 

Antarctic program 

Convener: J.C Behrendt 

9:20 ---- United States Research in Antarctica- E.P. Todd 

9:30 ---- New USGS Research Initiatives in Antarctica -

R.M. Hamilton 

9:40 ---- Antarctic Mapping and International Coordination -

R.B. Southard, W.J. Kosco 

10:00 --- Configuration of Eastern Gondwanaland - W. 

Hamilton 

10:20 ---Mineral Resources of Antarctica - P.D. Rowley, 

P.L. Williams, D.E. Pride 

10:40 --- Speculations on the Petroleum Resources of Antarctica-J.C. Behrendt, C.D. Masters 

11:00 --- Planned Marine Geophysical/Geological Surveys of 

the Wilkes Land and Ross Sea Margins - S.L. 

Eittreim 

11:20 --- Satellite Image Atlas of Glaciers: The Polar Areas -

R.S. Williams, Jr., J.G. Ferrigno 

11:40 ---Lunch 

1:10 ----Wind, Waves, and Swell in the Antarctic Marginal 

Ice Zone by Seasat Radar Altimeter - W.J. 

Campbell, N.H. Mognard 

1:30 ---- Surveying in Antarctica During the International 

Geophysical Year- W.H. Chapman 

1:50 ----The Dufek Intrusion of Antarctica and a Survey of 

its Minor Metals to Possible Resources - A.B. 

Ford 

2:10 ---- Crystallization of the Dufek Intrusion, Antarctica- G.R. Himmelberg, A.B. Ford 

2:30 ---- Geophysical Investigations of the Dufek Intrusion 

and the Surrounding Region- J.C. Behrendt 

2:50 ---- Geology of the Neptune Range, Antarctica - W.H. 

Nelson, P.L. Williams 

3:10 ---- Proterozoic to Mesozoic Mobile-belt Geology, Pensacola Mountains, Antarctica- D.L. Schmidt 

3:30 ----Sedimentology of the Horlick Formation (Lower 

Devonian), Ohio Range, Transantarctic Mountains- L. McCartan, M.A. Bradshaw, G. Ayers 

3:50 ---- Small-Scale Magnetic Features of the Polar Regions - J .C. Cain, D.R. Schmitz 

4:10 ----Paleomagnetic Studies in Antarctica - R.L. 

Reynolds, K.S. Kellogg 

IV 

October 13, 1983 

8:30 ---- Medical Problems of Polar Regions in the Early 

20th Century - S. Boyer 

8:50 ---- Mars-Analog Studies in Wright and Victoria 

Valleys, Antarctica- E.C. Morris, H.E. Holt 

9:10 ----An Isotopic and Chemical Study of Lake Vanda and 

Don Juan Pond, Antarctica - I. Friedman, A. 

Rafter, G.I. Smith 

9:30 ---- Climatic Significance of Lacustrine Deposits 

Around Lake V anda and Don Juan Pond, Antarctica- G.I. Smith, I. Friedman 

9:50 ---- Program for Mapping Antarctica - P.F. Bermel, 

C.E. Morrison 

10:10 --- The use of Satellite Technology in the Search for 

Meteorites in Antarctica- T.K. Meunier 

10:30 --- Glaciological and Geological Studies of Antarctica 

with Satellite Remote Sensing Technology- J.G. 

Ferrigno, R.S. Williams, Jr., C.S. Southworth, 

T.K. Meunier 

10:50 --- USGS Program at the South Pole - T.G. Edmondson, K.S. Covert 

11:10 --- Modeling the Movement of the Polar Ice Cap at the 

South Pole- T. Henderson 

11:30 --- Lunch 

Arctic program 

Convener: G. Gryc 

1:00 ---- History of U.S. Geological Survey Geologic Exploration and Mineral-Resource Evaluation, Arctic 

Alaska- G. Gryc, R.M. Chapman 

1:20 ---- Tectonics of Arctic Alaska - I.L. Tailleur, I.F. 

Ellersieck, C.F. Mayfield 

1:40 ---- Tectonic Evolution of the Arctic Continental 

Margin in the Beaufort and Chukchi SeasEvidence from Seismic Reflections - A. Grantz, 

S.D. May 

2:00 ---- The Arctic Platform in the National Petroleum 

Reserve in Alaska-Deposition, Deformation, 

and Petroleum Potential- C.E. Kirschner 

2:20 ---- Oil and Gas Resources of the North Slope, Alaska -

K.J. Bird 

2:40 ---- Petroleum Source Rock Richness, Type, and Maturity for Four Rock Units on the Alaskan North 

Slope-Are They Sources for the Two Oil Types? -

L.B. Magoon, G.E. Claypool 

3:00 ---- Emerging Recognition of the Nonfuel Mineral 

Resources of Arctic Alaska- D. Grybeck 

3:20 ----Coal Occurrence, Quality, and Resource Assessment, National Petroleum Reserve in Alaska -

G.D. Stricker 
October 14, 1983 

8:30 ----Permafrost and the Geothermal Regime - A.H. 

Lachenbruch, B.V. Marshall 

8:50 ---- Glaciation in Arctic Alaska- T.D. Hamilton 

9:10 ----A Pleistocene Sand Desert in Arctic Alaska- L.D. 

Carter 

9:30 ---- Sedimentary Facies on an Ice-Dominated SheH, 

Beaufort Sea. Alaska- P.W. Barnes, E. Reimnitz 

9:50 ----Quaternary Sedimentation on the Alaskan Beaufort 

SheH: Sediment Sources, Glacioeustatism, and Regional Tectonics - D.A. Dinter 

10:10 ---Permafrost and Related Engineering Problems on 

the North Slope and Beaufort SheH, Alaska -

O.J. Ferrians, Jr. 

10:30 --- Quaternary Microfossils on the Arctic SheH: Biostratigraphy and Paleoecology - KA. McDougall 

10:50 ---A Comparison of Numerical Results of Arctic Sea 

Ice Modeling With Satellite Images - Chi-Hai 

Ling, C. Parkinson 

11:10 --- Arctic Sea Ice by Passive Microwave Observations 

From the Nimbus-5 Satellite- W.J. Campbell, P. 

Gloersen, H.J. Zwally 

v 

11:30 --- Land Cover and Terrain Mapping for the Development of Digital Data Bases for Wildlife Habitat 

Assessment in the Yukon Flats National Wildlife 

Refuge, Alaska - M.B. Shasby, C. Markon, M.D. 

Fleming,D.L.Murphy,J.E. York 

11:50 ---Lunch 

1:30 ---- Geochemical Detection of Prospective Petroleum 

Areas in Arctic Regions - A.A. Roberts, T.J. 

Donovan, J.D. Hendricks, KI. Cunningham 

1:50 ---- Hydrology of the North Slope, Alaska- C.E. Sloan 

2:10 ---- Paleogeographic Affinities and Endemism of 

Cretaceous and Paleogene Marine Faunas in the 

Arctic - L. Marincovich, E.M. Brouwers, D.M. 

Hopkins 

2:30 ---- Remote Sensing Studies of Dynamic Environmental 

Phenomena in Iceland - R.S. Williams, Jr. 

2:50 ---- Correlation of Late Cenozoic Marine Transgressions 

of the Arctic Coastal Plain With Those in Western 

Alaska and Northeastern Russia- J.K. Brigham 

U.S. GEOLOGICAL SURVEY POLAR RESEARCH 

SYMPOSIUM-ABSTRACTS WITH PROGRAM 

INTRODUCTION 

THE GEOLOGICAL SURVEY IN 

POLAR PERSPECTIVE 

BY JOHN C. REED, SR. 1 

In 1958, legislation was passed that authorized 

the Survey to make studies in Antarctica Before 

that time, so far as I know, only three men, two 

geologists and one topographic engineer, did 

Survey work in the Antarctic with authorization 

and funding from other agencies. Even now 

Survey work in the Antarctic is supported largely 

by the National Science Foundation. 

Most of the Survey's Arctic work has been in 

Alaska Administratively such studies were not 

separated from projects in non-Arctic parts of 

Alaska Because of time restrictions this discussion is limited largely to the geologic work of the 

Survey's old Alaskan Branch. Survey field investigations began in Alaska in 1889. The first appropriation item for Alaska was in 1895, for $5,000. 

From then on came a long line of outstanding 

Survey Alaskan geologists. Starting in the 1930's, 

with more money, more men, better field methods, 

better communications, better transportation, and 

the like, the Survey's investigations increased 

greatly in number, size, and scope. The Survey's 

deep involvement is sketched in the Survey's programs of oil exploration in Naval Petroleum 

Reserve No.4, known as Pet 7, from 1944 to 1953. 

1

U.S. Geological Survey, retired. 

ANTARCTIC PROGRAM 

CONVENER: J. S. BEHRENDT 

UNITED STATES RESEARCH IN ANTARCTICA 

BY E. P. TODD1 

[No abstract] 

1

Natimal Scienre Foundation, Division of Polar Programs. 

1 

NEW USGS RESEARCH INITIATIVES 

IN ANTARCTICA 

BY ROBERT M. HAMILTON 

[No abstract] 

ANTARCTIC MAPPING AND 

INTERNATIONAL COORDINATION 

BY RUPERT B. SOUTHARD AND 

WILLIAM J. KOSCO 

International cooperation in Antarctica began 

long ago as expeditions from various countries frequently supported each others efforts. This was so, 

even though strong nationalistic mo~ements 

established territorial claims to Antarctica very 

early. 

It was during the third International Polar Year 

of 1957-58 that the spirit of cooperation in 

Antarctica ~as most highly developed. During 

1957-58 55 observatory stations were established 

to coo~rate in IGY programs in Antarctica 

Argentina, Chile, and the United Kingdom had 

already established stations prior to this time. 

Following the International Geophysical Year, 

the Scientific Committee on Antarctic Research 

(SCAR) was formed within the Interna~onal Council of Scientific Unions. It was deternuned that a 

scientific organization such as SCAR was required 

in order to provide the means for communication 

amongst the various countries active in Antarctica It is through SCAR that the true spirit of 

international cooperation prevails by providing 

the coordinating mechanism which allows the involved countries to survey and map the continent 

and to exchange the products of these mapping 

efforts. · 

Mapping Antarctica poses both technical. and 

political problems that are beyond companson. 

The most difficult technical problems are the 

logistics required for transpo~g personnel ~d 

equipment in that hostile enVIrOnment. Geodetic 
traverses are conducted by ground and air in order 

to establish ground control for mapping. People 

and equipment are moved in a leap-frog manner 

over a wide area, disregarding real or implied 

political boundaries. To carry out the spirit of 

cooperation, logistic efforts are shared. Several 

USGS geodetic traverses have been conducted 

jointly with the United Kingdom, New Zealand, 

and Australia 

The basic data input for map compilation comes 

from ground control and aerial photographs. In 

the early days of mapping in Antarctica the U.S. 

Navy VXE-6 squadron acquired trimetrogon 

aerial photographs over major map features. 

Ground control was established by surveyors from 

the U.S. Geological Survey. Trimetrogon photogrammetry was used to compile maps first in the 

Sentinel Mountains, Thurston Peninsula, Horlich 

Mountains, Executive Committee Range, and 

McMurdo Sound. In recent years, standard overlap aerial photography and image mapping have 

played an important role in the mapping process. 

Ninety 1:250,000-scale topographic maps have 

been compiled by USGS over the Transantarctic 

Mountains and Western Antarctica 

Working through the SCAR nations involved in 

mapping, the Antarctic standard symbols and 

specifications have been developed for preparing 

these maps. The Working Group on Geodesy and 

Cartography, a standing Committee within SCAR, 

published these symbols in 1961 and again in 

1980. An international agreement was reached in 

the early 60's on the basic horizontal and vertical 

datums to be used for mapping. Recently, agreement was reached (1981) to include the contribution to geodesy in this age of satellites, by 

changing the basic geodetic reference datum in 

Antarctica from the International Spheroid to the 

World Geodetic System. 

CONFIGURATION OF EASTERN 

GONDWANALAND 

BY WARREN HAMILTON 

Reconstructions of Gondwanaland by du Toit, 

by Smith and Hallam, and by many other recent 

authors vary in some details but agree on placing 

the east side of India against Antarctica, and the 

west side of Australia against some other continental mass now in, or under, Asia These fits, 

despite their wide acceptance, juxtapose unlike 

Indian and Antarctic Precambrian terrains, and 

2 

leave the marine Paleozoic and Mesozoic Tethyan 

north margin of India dead-ended against Antarctica or southwest Australia The conventional fits 

produce untenable juxtapositions and separations 

of Paleozoic and lower Mesozoic paleoclimatic and 

paleobiogeographic indicators. 

A reconstruction modified from those proposed 

by Carey, Krishnan, Shields, and a few others, 

placing the east side of India against the west side 

of Australia (see figure 1 ), satisfies constraints of 

ocean-floor ages and magnetic anomalies, accounts 

for known paleomagnetic pole positions, and 

matches continental geology and rifting histories. 

This fit, unlike the conventional one, leaves space 

for certain (Seychelles Plateau; Precambrian exposed), probable (N aturaliste Plateau and Broken 

Ridge), and possible (Kerguelen Plateau) continental fragments now in the Indian Ocean. Broken 

Ridge and the Kerguelen and Naturaliste Plateaus 

appear continental in foundering histories and 

some geophysical features. Naturaliste Plateau 

has yielded Cretaceous clastic sediments of continental provenance and continental basaltic and 

rhyolitic rocks; Kerguelen volcanic rocks are of 

types that could be either continental or oceanic, 

but they contain radiogenic strontium. Fossils in 

FIGURE !.-Reconstruction of Gondwanaland in Late Triassic 

and Early Jurassic time. The longitude lines, 15° apart, 

illustrate the projection. Continental fragments: B, Broken 

Ridge; F, Falkland Plateau; K, Kerguelen Plateau; N, 

N aturaliste Plateau; S, Seychelles Plateau. Late TriassicJurassic paleomagnetic poles: 1, Africa and South 

America; 2, Madagascar; 3, Australia (used for pole of map 

projection); 4, India; 5, East Antarctica Continents fitted 

to l,ooo-m isobaths. 
Kerguelen Tertiary lignites include wet-temperate 

austral araucarian and podocarpaceous conifers, 

and beech (Nothofagus), all of which are incapable 

of crossing lerge water gaps and hence require 

Late Cretaceous or Tertiary dry-land continuity 

with Antarctica or Australia, and continuous subsequent stand above sea level. Nepal (the northeast part of Indian plate) and Timor (the imbricated northwest edge of the Australian plate) have 

strikingly similar temperate to subtropical Permian marine faunas; the two terrains are juxtaposed by the reconstruction supported here, 

whereas they are far apart, and Nepal is at a 

continental-interior position and an impossibly 

high Permian paleolatitude, in the conventional 

assembly. 

MINERAL RESOURCES OF ANTARCTICA 

BY PETER D. ROWLEY, P. L. WILLIAMS, AND 

D. E. PRIDP 

Metallic and nonmetallic mineral occurrences 

are abundant in Antarctica The most significant 

known deposits are of iron, copper, and coal. In the 

Precambrian shield of East Antarctica, for example, iron is present as banded iron-formation and 

as magnetite in veins, pods, and schist. The largest 

deposits of iron are in the Prince Charles Mountains, where bodies of banded iron-formation at 

least as thick as 400 m extend, mostly under the 

ice, for at least 120 km. Widely scattered morainal 

boulders and outcrops of iron-rich rock suggest 

that undiscovered iron deposits are also distributed over many other parts of East Antarctica 

Magmatic iron is present in Pleistocene lava flows 

on Brabant Island, Antarctic Peninsula The 

Jurassic stratiform gabbroic Dufek intrusion in 

the Transantarctic Mountains contains locally 

abundant magnetite and minor copper sulfides, 

and it may contain significant volumes of chromium, nickle, vanadium, iron, and platinum-group 

minerals. However, the base of the intrusionwhere economically important metals are most 

likely to be concentrated-is not exposed. Lowgrade copper and related metals are abundant in 

the Andean belt (mostly of Early Jurassic through 

Cenozoic age) of the Antarctic Peninsula Here 

possible porphyry copper-molybdenum deposits 

and associated hydrothermal vein deposits occur 

on King George Island, Livingston Island, Anvers 

Island, the Melchior Islands, Brabant Island, 

Lassiter Coast, and eastern Ellsworth Land. 

3 

Phlogopite and rock crystal occur in Queen Maud 

Land and Enderby Land, and graphite and beryl 

are locally abundant in other parts of East Antarctica Sizeable coal deposits are present in the 

Transantarctic and Prince Charles Mountains, and 

smaller occurrences are in many other parts of 

East Antarctica 

Gondwana reconstructions suggest that many 

more mineral deposits occur in Antarctica However, ice covers nearly 98 percent of the continent, 

and few of the bedrock areas have even been prospected or geologically, geophysically, or geochemically mapped in detail. No known mineral deposits 

now can be developed economically. Probably 

some presently known deposits in Antarctica 

would be drilled or perhaps even mined if they 

were located in a continent more favorable for 

development. However, Antarctica's severe 

climatic and logistic constraints and the fact that 

there are no international agreements concerning 

mineral rights or mining make it unlikely that exploitation will occur for many years. 

1

Department of Geology and Mineralogy, The Ohio State University, Columbus, 

OH 43210. 

SPECULATIONS ON THE 

PETROLEUM RESOURCES OF ANTARCTICA 

BY JOHN C. BEHRENDT AND 

CHARLES D. MASTERS 

There are no known petroleum resources in 

Antarctica, and the petroleum industry is not particularly interested at present. Economic and 

political considerations may change this in the 

next few years, and exploration and exploitation 

are possible within one or two decades. A number 

of countries are actively carrying out multichannel 

seismic reflection surveys of the Antarctic continental margin, which are obviously focused on 

petroleum resource studies. Technology development will probably occur at a more rapid rate than 

research, exploration, and legal developments. By 

contrast, hard mineral exploitation in Antarctica 

is probably much further in the future. The only 

types of potentially exploitable petroleum resources in Antarctica from economic considerations would be giant or supergiant fields of which 

probably only four to ten supergiants remain to be 

discovered in the world. The points made based on 

my study of the available information on potential 

petroleum resources in Antarctica can be summarized as follows: 
1. West Antarctica is probably the most prospective area of Antarctica because it likely contains large areas of unmetamorphosed sedimentary rock of post-rift age. It is comprised 

of a number of microplates that have moved 

significantly since the break-up of Gondwanaland. East Antarctica probably contains a 

number of subglacial sedimentary basins particularly adjacent to high mountain ranges 

and within the probable failed rift in the 

Amery Ice Shelf area. 

2. Because of the moving grounded ice sheet 

several kilometers thick which covers most of 

Antarctica, the only practical areas for possible exploitation, were petroleum to exist, are 

the continental margins (possibly including 

the parts covered by ice shelves) with the 

most likely areas those bordering the Ross, 

Amundsen, Bellingshausen, and Weddell 

seas, in West Antarctica, and the Amery Ice 

Shelf in East Antarctica. 

3. The sparse geophysical data suggest that there 

is a > 8 kilometer thick section of sedimentary rock beneath the Ross and 14-15 km 

section beneath the Weddell Sea continental 

shelves. The Bellingshausen Basin probably 

contains > 3 km of sedimentary rock. There 

is no available information on sedimentary 

rock thickness beneath the continental 

shelves bordering the Amundsen Sea and 

Amery Ice Shelf area but recent geophysical 

cruises can be expected to provide more information soon. 

4. DSDP holes on the Ross Sea continental shelf 

indicate the presence of rocks from Oligocene 

to Pleistocene in age. Sedimentary rocks of 

Cretaceous or possibly Jurassic age might be 

present in the deepest parts of the section indicated by seismic reflection data and depths 

estimated from aeromagnetic data. Jurassic 

and Cretaceous and Tertiary sedimentary 

rocks are probably present beneath the continental shelf and adjacent glacierized areas of 

East Antarctica based on a number of samples by several investigators. 

5. There is presently no direct information on the 

petroleum geology beneath Antarctic continental shelves relative to source and reservoir 

rocks, with the exception of the shows of gas 

reported in core holes beneath the Ross Sea 

continental shelf. 

4 

6. If future geophysical and geological (deep drilling) research were to indicate certain areas as 

worth exploration, programs of environmental research would be necessary to study possible meteorological, glaciological, oceanographic, and geologic hazards that might be 

encountered that would adversely affect 

future exploration or exploitation. Concomitant biological research programs into the 

fragile ecosystems that might be affected by 

possible blowouts or oil spills would also be 

required. 

PLANNED MARINE GEOPHYSICAL GEOLOGICAL 

SURVEYS OF THE WILKES LAND AND 

ROSS SEA MARGINS 

BY STEPHEN L. EITTREIM 

In January and February of 1984, the icestrengthened S.P. LEE will carry out 24-channel 

seismic surveys to better define the basins and 

seismic stratigraphy of parts of the Antarctic 

margin south of Australia and New Zealand Gravity and gradiometer-magnetic data also will be collected underway, as well as sonobuoy refraction 

and 3.5 and 12kHz echo sounding. Seafloor sampling will be done for age determination, for physical and geochemical properties of sediments, and 

for contained gases. A deep-towable side-scan 

system will be available for investigation of 

morphologic features. 

Australia and New Zealand rifted away from 

Antarctica in the middle of the Cretaceous producing rift basins, some of which are hydrocarbonrich, such as the Gippsland basin north of Tasmania. DSDP drilling in the region shows that the 

early phases of opening were a time of deposition 

of euxinic clays and silts, reflecting restricted 

basin circulation and probable local anoxic 

bottom-water conditions. Prior to the Eocene, a 

subtropical climate prevailed. On the Ross Sea 

Shelf, German and French seismic data and DSDP 

cores show sediment many kilometers thick in 

three north-trending basins, with interstitial gases 

suggesting a thermogenic source. The Wilkes 

Land to Victoria Land margin has been less explored, due partly to more difficult ice conditions, 

but thick sediments exist in places, and one major 

basin, the Wilkes basin, may be a structural 

counterpart of the Otway basin of southern Australia. In sum, the meager data existing at present 
give reason to consider this part of the Antarctic 

margin as a possible petroleum resource area 

Besides the resource questions, several significant marine-geologic questions can be addressed 

on this ice-fringed passive continental margin. 

Because of its relative youth and the probability 

that it has been sediment starved in the latter part 

of the Tertiary, the Antarctic margin here is a 

good place to study post-rift subsidence and structures related to the Gondwana breakup. The fracture zones tracing the motion of Australia-New 

Zealand from Antarctica intersect the Antarctic 

margin obliquely; the short ridge segments are offset by large distances, and the mid-ocean ridge 

axis is abnormally close to the margin, similar to 

the equatorial Atlantic configuration. How these 

fracture zones and the ridge proximity have influenced basin development are interesting questions 

for study. Two major climatic events, the drastic 

cooling of the Terminal Eocene Event and the ice 

sheet growth in the Miocene probably left prominent signatures in the seismic stratigraphy of this 

margin. 

The hypotheses which exist to explain the anomalously great depth of the shelf break of Antarctica (500 m) need to be tested. The deep shoreparallel troughs that exist on the inner shelf 

present an interesting topic of study as well as the 

general questions of ice influence on sedimentation 

and morphology and how this influence might contrast to Arctic processes. In two months of time on 

the LEE (minus two weeks of transit time) we can 

only hope to establish a beginning toward addressing these and perhaps other more interesting questions for future years' work. 

SA TEL LITE IMAGE ATLAS OF GLACIERS: 

THE POLAR AREAS 

BY RICHARD S. WILLIAMS, JR., AND 

JANE G. FERRIGNO 

In June 1977, the U.S. Geological Survey 

(USGS) began a long-term project to prepare a 

USGS Professional Paper, "Satellite Image Atlas 

of Glaciers." Now nearing completion, with publication expected in 1985, the Atlas involves 55 glaciologists representing 30 United States, foreign, 

and international organizations in an effort to produce a benchmark study of the glacierized areas of 

Earth. Landsat images provide the common data 

base for locating, describing, and mapping: (1) the 

5 

areal extent of the Antarctic and Greenland ice 

sheets and ice caps in Iceland, Svalbard, the Russian Arctic islands, and northern Canada; (2) the 

termini of most large valley glaciers; and (3) the 

termini of tidal outlet glaciers. 

The polar areas, especially the Antarctic, represent some of the most poorly mapped regions of 

our planet. Antarctica is estimated to contain 90 

percent of the glacier ice on Earth, yet only 20 percent of the continent has been mapped at a scale of 

1:250,000 or larger. Kvitoya, a small, ice-capped 

island east of Nordaustlandet in Svalbard, was, 

until the availability of Landsat, mapped as being 

thin and cigar-shaped (see the Central Intelligence 

Agency's Polar Regions Atlas, May 1978). Landsat images showed the island to be oval, and new 

Norwegian maps of the area now show this radical 

change in shape. A comparison of Landsat images 

with published maps of the Arctic and Antarctic 

reveals many discrepancies, including incorrect 

positions of glacier margins, inaccuracies in geographic locations of glaciers, coastlines, and offshore islands. 

In addition to serving as the basis for the preparation of the "Satellite Image Atlas of Glaciers" to 

support future and retrospective studies of fluctuation in glacier termini and global climatological 

studies, Landsat images are being increasingly 

used as base maps (controlled or uncontrolled) to 

plot regional glaciological, geological, and geophysical data up to scales of 1:250,000 for Landsat 

multispectral scanner (MSS) images and up to 

1:100,000 for Landsat 3 return beam vidicon 

(RBV) and Landsat 4 thematic mapper (TM) images. Landsat images have been used, in a timelapse fashion, to monitor advance or recession of 

glaciers, to measure the velocity of outlet glaciers, 

and to monitor fluctuations in proglaciallakes. 

Because of the brief field season and logistical 

costs and mobility difficulties in polar areas, 

satellite data will be increasingly used to monitor 

dynamic phenomena in these areas. The ''Satellite 

Image Atlas of Glaciers," which, in the polar 

areas, involves a mutually beneficial exchange of 

scientific information among United States, Canadian, British, Norwegian, Swedish, Soviet, Danish, 

Icelandic, and New Zealand scientists, is representative of the type of multinational cooperative 

research endeavors that are possible with such 

data and which will jointly lead to better scientific 

knowledge about the polar areas. 
WIND, WAVES, AND SWELL IN THE ANTARCTIC 

MARGINAL ICE ZONE BY SEASAT RADAR 

ALTIMETER 

BY WILLIAM J. CAMPBELL AND 

NELLY M. MOGNARD1 

During the Austral winter of 1978, the Seasat 

satellite acquired repetitive radar altimeter observations of the oceans surrounding Antarctica By 

averaging these observations for three-day periods, quasi-synoptic fields of ocean surface wind 

speed, significant wave height, and significant 

swell height have been computed for the entire 

three months the satellite operated. The generation, migration, and attenuation of swell in the 

southern oceans have been measured for the first 

time. 

Extensive areas of pronounced significant wave 

height and swell height were found to occur somewhere near the Antarctic marginal ice zone every 

few days during the winter 1978. During the 

period 7-9 October 1978, storms between Antarctica and Australia and in the eastern South Pacific 

with surface wind speeds as high as 20 m/s generated large areas with significant wave heights as 

large as 16 m and significant swell heights as large 

as 12 m. Extensive wave trains with significant 

wave height as large as 10-12 m and swell as large 

as 8-10 m were observed to impact large areas of 

the Antarctic marginal ice zone. Return signals 

from the ocean surface and the sea ice cover were 

analyzed, and it is shown that phenomena within 

the ice can be observed with the radar altimeter 

such as the opening of the Weddell Sea polynya in 

September 1978. See figures 2, 3, and 4. 

1

Groupe de Recherche de Geodesie Spatiale-CNES Toulouse, France. 

SURVEYING IN ANTARCTICA DURING THE 

INTERNATIONAL GEOPHYSICAL YEAR 

BY WILLIAM H. CHAPMAN 

The Antarctic International Geophysical Year 

(IGY) program starting in 1956 initially emphasized the gathering of geophysical measurements 

throughout the western part of the continent. At 

the bases, the major scientific programs involved 

meteorology, seismology, geomagnetism, and 

measurements of the ionosphere. The traverse 

parties' efforts were directed toward glaciology, 

geology, and geophysics. As IGY scientists made 

flights and ground traverses into the interior of 

6 

the continent, they discovered that the existing 

maps contained many errors, particularly where 

the original exploration was by aircraft. The 

plotted flight paths of Byrd, Ronne, and the other 

earlier explorers contained position errors as large 

as 60 miles, and the aircraft crews had a tendency 

to exaggerate their discoveries. As a result, it was 

very difficult to correlate the actual topography 

with that shown on the map; nonexistent mountains were shown, and existing mountains were 

plotted with large positional errors. There was one 

case where a 20,000-foot mountain that was shown 

on a map could not be found. It was obvious that 

the scientists needed maps for navigation, topographic data, and traverse planning that were 

more accurate than those available. 

In an attempt to utilize new technology for producing the needed maps, Major Lassiter led an 

Air Force expedition of two DC-3 aircraft to the 

Ellsworth Station on the Weddell Sea During 

November and December of 1957, a test network 

of 10 control points was established 200 miles 

south of the Ellsworth Station on the Filchner Ice 

SheH in the vicinity of the Pensacola Mountains. 

The positions of these points were determined 

by solar altitude measurements made every hour 

for 24 hours. The test site elevations were 

measured with barometric altimeters. The equipment that was to shorten the mapping cycle, a 

radio ranging system, was tested in January and 

proved to be unsatisfactory. Because of a strong 

ionospheric reflection, the range was limited to 75, 

instead of the expected 300, miles. 

The following season, U.S. Geological Survey 

topographic engineers were assigned to IGY ship 

expeditions and geophysical traverses. In addition 

to navigating the traverses, the engineers were to 

survey any mountain ranges encountered. This 

was done by establishing positions by solar 

altitude measurement and elevations by barometric altimetry. The surveyor was generally at 

traverse camps, which were located on the flat 

snow surface within view of the mountains. The 

coordinates were then projected to the mountain 

peaks by intersection from a taped baseline. Elevations were transferred by vertical angle observations. This technique for obtaining control for 

mapping continued for several years and was then 

replaced by helicopter-supported survey traverses 

using electronic distance measuring instruments. 

The Navy's VXE-6 squadron was taking aerial 

photographs over major mountain ranges using 
FIGURE 2.-Southem ocean field of significant wave height (m) derived from the Seasat radar altimeter measurements for Oct& 

her 7 to 9, 1978. 

P-2V aircraft equipped with trimetrogon cameras. 

The aerial photography was combined with the 

control established by the surveyors at the U.S. 

Geological Survey, Branch of Special Maps, to 

produce 1:250,000-scale topographic maps. The 

first maps produced covered the Thurston Peninsula, Sentinel Mountains, Horlick Mountains, Executive Committee Range, and McMurdo Sound. 

7 

THE DUFEK INTRUSION OF ANTARCTICA AND 

A SURVEY OF ITS MINOR METALS RELATED TO 

POSSIBLE RESOURCES 

BY ARTHUR B. FORD 

The Dufek intrusion is an unusually large differentiated layered mafic igneous complex of Jurassic 

age in the northern Pensacola Mountains (lat 82 o 
270°~--~~~~----~~~ 

8 

FIGURE 3.-Southern ocean field of surface altimeter measurements (m) for October 7 to 9, 1978. 

30' S., long 50 o W.). Although it is mostly covered 

by ice, geophysical surveys indicate that it has an 

area (50,000+ km2

) compar~ble to that of South 

Africa's Bush veld Complex: Geologic studies by 

U.S. Geological Survey parties in 1965-66, 

1976-77, and 1978-79 determined that, of its total 

8-9 km estimated thickness, nearly 2 km of a 

lower (not lowest) part of the body is exposed in 

the Dufek Massif and about 1. 7 km of the Feenriched highest part is exposed in the Forrestal 

Range. Major concealed stratigraphic parts are a 

8 

1.8- to 3.5-km-thick basal section beneath the 

Dufek Massif rocks and a 2- to 3-km-thick intermediate interval, underlying Sallee Snowfield, between the two exposed sections. Except for late 

silicic differentiates of the Lexington Granophyre 

at the top, the rocks are generally well-layered 

cumulates of predominantly gabbroic composition. These gabbroic cumulates chiefly contain 

cumulus plagioclase and two pyroxenes (augiteferroaugite and inverted pigeonite); additionally, 

cumulus magnetite and ilmenite are abundant in 
FIGURE 4.-Southem ocean field of minimum swell height (m) deduced from the significant wave height and surface wind speed 

measurements by Seasat altimeter and using Pierson and Moskowitz wave model for October 7 to 9, 1978. 

the Forrestal Range section. In many areas, the 

gabbroic cumulates are interlayered with conspicuous but volumetrically minor layers, a few centimeters to tens of meters thick, of plagioclase 

cumulate (anorthosite and leucogabbro), pyroxene 

cumulate (pyroxenite), and Fe-Ti oxide cumulate 

(magnetitite) that typically show modal gradation 

upward from sharp basal to gradational top contacts with the gabbroic cumulates. Most layers of 

this kind have great lateral continuity with little 

9 

variation in thickness: one, the Frost Pyroxenite, 

is traceable for 35 km before disappearing under 

ice cover. The general association of such layers 

with cut-and-fill channel structures (troughs) 

suggests a depositional origin related to magmacurrent activity. Layer-parallel alinements of xenolith trains in many places also indicate current 

activity. 

The intrusion was emplaced in a multiply deformed mobile belt at the margin of the Antarctic 
craton, in which strong compressive deformations 

are of late Precambrian and Cambrian(?), Late Cambrian to Silurian, and probable Triassic age. K-Arage determinations of 172+4 m.y. indicate contemporaneity of the intrusion with sills, dikes, and 

flood lavas of the Middle Jurassic tholeiitic Ferrar 

igneous province throughout the Transantarctic 

Mountains. Representatives of the Ferrar in the 

Pensacola Mountains have high Si02 contents 

(53-55 weight percent), anomalously high 87Srf86Sr 

initial ratios (0.7104-0.7126), and other chemical 

and petrographic features that characterize the 

province elsewhere. If the original magma of the 

Dufek intrusion had similar characteristics, this 

body provides a record of strong fractionation of a 

mafic magma different from those inferred for other 

major layered intrusions, which contain less Si02 

and more MgO. The Ferrar province, including the 

Dufek intrusion, may have formed in a failed~rift 

arm of a radial-rift system centered near the SoUth 

America-Africa-Antarctica join and associated with 

the breakup of this part of Gondwanaland. 

Other major intrusions of this type contain economically significant magmatic deposits of one or 

more metals, generally concentrated in lower parts 

of the bodies and associated with early mafic and 

ultramafic cumulates. In view of the small percentage of rock exposure and the present reconnaissance scale of investigation, nearly all such de-

,posits are considered to be "speculative resources" 

of the Dufek intrusion. Disseminated sulfides have 

been found locally in trace amounts to several percent, the greatest amounts in Fe-Ti oxide-rich 

layers in the Forrestal Range. A reconnaissance 

geochemical survey of average-appearing rocks 

shows marked enrichment in Cu, V, Ti, Pt, Pd, and 

Sin the upper (Forrestal Range) section in comparison with the lower (Dufek Massif) section, and 

corresponding depletion in Cr and Ni. The variations relate to differentiation by fractional crystallization. Pt, Pd, and Rh have been found only in 

concentrations near or below their limits of determination (Pt, 10 ppb; Pd, 4 ppb; Rh, 5 ppb) in the 

lower section, but in greater concentrations (max 

35 ppb Pt, 44 ppb Pd, and 12 ppb Rh) in the upper 

section. Platinum-group minerals have not been 

found. 

Petrologic comparisons with other complexes, 

including use of cumulus a-rival of pigeonite as a 

correlation marker, suggest that the major pyroxenitic members of the Dufek Massif section lie at a 

position analogous to a level about 2 km or more 

10 

above the ·chief platinum-group-metal horizons of 

the pyroxenitic Merensky Reef of the Bushveld 

Complex. The Merensky-equivalent level in the 

Dufek intrusion is probably in the middle to upper 

part of the concealed basal section. Considering 

Antarctic operating costs, platinum-group metals 

would be of chief resource interest, but the absence 

of placers and soils will make exploration difficult. 

Correlation studies suggest that V may be a useful 

pathfinder element in a geochemical exploration 

for the metals within exposed units; however, drilling would be needed to explore basal layers, where 

metals are most likely to occur. 

CRYSTALLIZATION OF THE 

DUFEK INTRUSION, ANTARCTICA 

BY GLEN R. HIMMELBERG AND A. B. FORD 

The Dufek intrusion is an unusually large differentiated layered gabbro of Jurassic age in the 

northern Pensacola Mountains (lat 82°30' S., long 

50° W.). The intrusion is mostly covered by ice, 

but geophysical surveys indicate it has an area of 

50,000+ km2, comparable to that of the Bushveld 

Complex. The gabbros are exposed in two partial, 

nonoverlapping sections. The lowermost 1.8 km of 

exposed rocks make up the Dufek Massif section, 

and the uppermost 1. 7 km of rock make up the 

Forrestal Range section. The concealed intermediate section between the two ranges is estimated to be 2-3 km thick, and geophysical evidence suggests that the concealed basal section is 

1.8-3.5 km thick. Thus the total thickness of layered rocks may be as much as 8-9 km. 

The layered rocks are dominantly gabbro with 

lesser amounts of anorthosite and minor pyroxenite. A 300-m-thick granophyre layer caps the intrusion. The anorthosites are plagioclase and 

plagioclase-augite cumulates; the gabbros are 

dominantly plagioclase-augite-inverted pigeonite 

cumulates except near the base of the Dufek 

Massif section where the Ca-poor pyroxene is orthopyroxene, and in the upper Forrestal Range 

section where the magma differentiated beyond 

the two-pyroxene stability field and ferroaugite is 

the only cumulus pyroxene. Titaniferous magnetite and ferrian ilmenite are cumulus phases in 

most of the layered rocks from the uppermost 

Dufek Massif section through the Forrestal Range 

section. 
In the upper part of the Dufek Massif section 

and in the Forrestal Range section the anorthosites have sharp basal contacts and grade upward 

into gabbros, a sequence that is repeated in a 

cyclic manner. The succession of appearance of 

cumulus phases in these sequences indicate the 

crystallization sequence plagioclase, plagioclase 

+ augite, and plagioclase + augite + pigeonite. In 

the lower part of the Dufek Massif section the 

anorthosites have sharp basal and upper contacts 

with gabbro and there are no sequences of 1-phase 

cumulates progressing through 2- and 3-phase 

cumulates to indicate a crystallization sequence. 

Very slight changes in bulk composition or phase 

boundaries can affect crystallization sequence, and 

marked changes in crystallization sequence have 

been documented for other large layered intrusions. Thus there is no reason to infer that the 

crystallization sequence of the concealed basal section and of most of the Dufek Massif section was 

the same as the sequence for the upper part of the 

intrusion. 

Cumulus pyroxenes show a general iron enrichment with stratigraphic height. Superimposed on 

the trend are (1) a 1-km-thick section in the lower 

part of the exposed intrusion that shows slight to 

no iron-enrichment and (2) a marked reversal in the 

Fe/(Fe+ Mg) ratio at about 1 km below the top of 

the body. Cumulus plagioclase in the gabbros 

shows a general decrease in anorthite content with 

stratigraphic height and also shows a marked 

reversal in composition near the top of the body. 

The section with little pyroxene fractionation is 

not reflected in the plagioclase trend, and there are 

other reversals in the plagioclase composition 

trend that are not paralleled by reversals in the 

pyroxene trend. These differences in detail may 

reflect, in part, different degrees of interaction of 

cumulus minerals with upward migrating intercumulus liquid. The chemistry of cumulus irontitanium oxides are dominated by subsolidus reequilibration, although the contents of V20 3 and 

AlJla in ilmeno-magnetite parallels the pyroxene 

compositional trend. 

The layering, textures, and mineral chemistry 

variation with stratigraphic height make it clear 

that the dominant process in the formation of the 

intrusion was fractional crystallization with accumulation, or crystallization, from the base upward. The cyclic sequence of plagioclase cumulates 

grading upward to plagioclase-pyroxene cumulates suggests either periodic convective overturn 

11 

of magma or influx of more primative magma to 

the crystallization site. The major reversal in 

mineral fractionation trends near the top of the intrusion, which coincides with an angular discordance in layering dip, strongly indicates an influx of 

new magma at the site of crystallization. Reversal 

magnitudes suggest incursion of either less fractionated magma from some other part of the chamber or mixing of primative magma with Fe-rich 

residual magma. 

GEOPHYSICAL INVESTIGATIONS OF THE DUFEK 

INTRUSION AND THE SURROUNDING REGION 

BY JOHN C. BEHRENDT 

Aeromagnetic, gravity, and seismic reflection 

measurements made in 1957, 1963-64, 1965-66, 

and 1978 over the Dufek layered mafic intrusion of 

172±4 m.y. age in the Pensacola Mountains area 

of Antarctica have allowed extension of the known 

geology beneath areas covered by thick ice. 

A combined aeromagnetic and radio echo icesounding survey (4,200 km of traverse) made in 

1978 over the Dufek intrusion suggests a minimum area of about 50,000 km2

, making it comparable in size with the Bushveld Complex of Africa. 

Comparisons of the magnetic and subglacial 

topographic profiles illustrate the usefulness of 

this combination of methods in studying bedrock 

geology beneath ice-covered areas. Rocks are exposed in only 3% of the inferred area of the intrusion. It is about 400 km long along a NNE trend 

from about 80°45' S. across the front of the Transantarctic Mountains. Interpretation of the magnetic data indicates that the northern part of the 

intrusion is downdropped about 4 km across the 

mountain front and underlies the 1, 700-m-deep 

Crary trough. 

West Antarctica has been interpreted to comprise several crustal blocks (microplates) that 

moved and rotated into their present configuration. In a recent paper Dalziel and Elliott (1982) 

suggested that the Ellsworth Mountain block was 

formerly placed against the present Transantarctic Mountains. Thus, if the Ellsworth Mountain 

block earlier occupied the area presently underlain 

by the northern part of the Dufek intrusion, the 

block must have been displaced either prior to or 

synchronous with rifting in Early Jurassic time 

that led to emplacement of that intrusion and the 

coeval Ferrar intrusive group. 
Magnetic anomalies measured a few hundred 

meters above outcrops of the intrusion range in 

peak-~trough amplitude from about rv 50 nT over 

the lowermost exposed portion of the section in the 

Dufek Massif to about rv3,600 nT over the uppermost part of the section in the Forrestal Range. 

Theoretical magnetic anomalies, computed from 

models based on the subice topography fitted to 

the highest-amplitide observed magnetic anomalies, required normal and reversed magnetizations 

ranging from 1 o-4 to 10-2 emu/cm3 having directions and magnetizations consistent with measurements previously made on oriented samples. This 

result is interpreted as indicating that the Dufek 

intrusion cooled through the Curie isotherm during one or more reversals of the Earth's magnetic 

field. 

A broad regional Bouguer anomaly has gradients parallel to the northwest edge of the Pensacola Mountains block. Bouguer anomaly values 

decrease from 82 to -90 mgal across this transition from West Antarctica to East Antarctica 

Theoretical profiles fitted to the gravity data indicate either an abnormally thin crust on the West 

Antarctica side or a normal crust on the West Antarctica side and a steep steplike transition from 

West Antarctica to East Antarctica that suggests 

a fault extending from the crust-mantle boundary 

to near the surface. Gravity, magnetic, and seismic 

data suggest a thick section of low-velocity, lowdensity, nonmagnetic, presumably sedimentary 

rock beneath the ice northwest of the Pensacola 

Mountains. A least-squares regression of the 

Bouguer anomalies compared with elevation in the 

Pensacola Mountains area suggests that the amplitude of the gravity anomaly associated with the 

Dufek intrusion is about 85 mgal, corresponding 

to about 8.8- to 6.2-km thickness for the intrusion, 

assuming reasonable density contrasts. 

GEOLOGY OF THE NEPTUNE RANGE, 

ANTARCTICA 

BY WILLIS H. NELSON AND PAUL L. WILLIAMS 

Two superposed unconformities separate the 

rocks of the Neptune Range into three sequences. 

The oldest sequence, the Patuxent Formation of 

late Precambrian age, consists of several thousand 

meters of argillaceous metasandstone (metasubgraywacke), slate, and minor amounts of conglomerate. Igneous rocks, mostly mafic extruSiive 

rocks, locally compose important members of the 

12 

Patuxent Formation. These rocks were all tightly 

folded during the Beardmore orogeny. 

The Nelson Limestone, and shale, siltstone, and 

fine-grained sandstone of the late Cambrian Wiens 

Formation, unconformably overlie the Patuxent 

Formation. Silicic volcanic rocks, mostly volcaniclastic, derived from centers within the Neptune 

Range compose the Gambacorta Formation, including the Hawkes Rhyodacite Member. Locally, 

the upper part of the Gambacorta interfingers 

with the lower part of the Wiens Formation. 

The Cambrian and older rocks were moderately 

to strongly deformed during the early Paleozoic 

Ross orogeny, later beveled by. erosion, and are 

now overlain unconformably by weakly to locally 

strongly folded clastic rocks of Ordovician(?) to 

Devonian ages. Still later, massive diamictite-the 

Gale Mudstone, probably tillite, of Permian(?) 

age-was deposited. 

The general trends of structures in the Neptune 

Range and in the Transantarctic Mountains, of 

which the Neptunes are a part, all generally 

parallel the Pacific-Atlantic edge of the Antarctic 

craton, which lies mostly in eastern longitudes. 

Although published descriptions of rocks of the 

Ellsworth Mountains about 500 km from the Neptune Range suggest possible correlations with 

rocks of the Neptune Range, structural trends in 

the Ellsworth Mountains at nearly right angles to 

the trend of the Transantarctic Mountains, suggest different tectonic histories for these two 

areas. 

PROTEROZOIC TO MESOZOIC MOBILE-BELT 

GEOLOGY, PENSACOLA MOUNTAINS, 

ANTARCTICA 

BY DWIGHT L. SCHMIDT 

The Pensacola Mountains consist of four unconformable sequences of (I) graywacke (oldest), (2) 

platform, (3) molasse, and (4) continental (youngest) deposits that were deformed during three successive pre-Jurassic compressional tectonic events 

and a superposed Jurassic extensional rift event. 

The first sequence of Middle .Proterozoic graywacke deposits (Patuxent Formation), at least several kilometers thick, consists of turbidite quartzbearing sandstone and slate and volcanic rocks. 

The distribution of intercalated basalt flows, some 

pillow-structured, and sparse dacitic to rhyolitic 

flows, ignimbrites, and tuffs suggests a nearby 

island-arc source on the West Antarctic side of the 
Pensacola Mountains. These subduction-related 

rocks were isoclinally folded and thrust most likely 

toward the East Antarctic shield during the Late 

Proterozoic Beardmore orogeny. 

A major angular unconformity underlies the second sequence consisting of extensive platform 

deposits of Lower Cambrian archaeocyathidbearing limestone and Middle Cambrian trilobitebearing limestone (Nelson Limestone) that are 

overlain by shale (Wiens Formation), and silicic 

volcanic rocks (Gambacorta Formation) including 

rhyolitic ignimbrite (510±35 Ma) of caldera origin. 

The second sequence was intruded by calc-alkalic 

granite plutons of Late Cambrian age and deformed 

during the Cambrian-Ordovician Ross orogeny, 

which is interpreted as a cratonization event that 

was distally associated with subduction-related collisional tectonics in West Antarctica. 

The third sequence is the pre-Devonian Neptune 

Group that is above an angular unconformity and 

consists of basal orogenic conglomerate and more 

than 1,500 m of quartz-sandstone molasse that 

resulted from the erosion of the early Paleozoic 

mountains of the Ross orogeny. The fourth sequence of continental deposits of the Beacon 

Supergroup disconformably overlies the Neptune 

Group. The Beacon Supergroup consists of Devonian quartz sandstone (Dover Sandstone), Permian glacial tillite (Gale Mudstone), and Permian 

siltstone and shale (Pecora Formation) containing 

glossopterid-bearing coal beds. 

The rocks of the Pensacola Mountains again 

were deformed into tight to open folds during the 

Weddell orogeny of Triassic age. This latest compressional event was caused by intracratonic 

orogeny distally associated with latest Paleozoic 

to early Mesozoic subduction of the Pacific Ocean 

beneath the northern margin of West Antarctica 

(including the ancestral Antarctic Peninsula). The 

transverse structure of the Ellsworth Mountains 

probably was a direct, in-situ product of Weddell 

orogeny and does not require rotation as interpreted in a 1969 study by J .M. Schopf. The Weddell orogeny resulted in the final consolidation of 

this part of Gondwanaland. 

During Early and Middle Jurassic time, a Transantarctic continental rift extensionally split the 

East Antarctic craton from West Antarctica as 

Gondwanaland began to break up. Continental 

tholeiitic flood basalt (Kirkpatrick Basalt) was 

deposited on, and tholeiitic diabasic sills (Ferrar 

Dolerite) were intruded into, the rift margin in the 

13 

Transantarctic Mountains; the huge stratiform 

gabbroic pluton of the Dufek intrusion was intruded into the Pensacola Mountains. The continental rifting was shortly followed, during Late 

Jurassic time, by more vigorous extension resulting from major transform faulting, and perhaps by 

minor oblique formation of oceanic crust as East 

Antarctica was right laterally displaced 500 to 

1,000 km relative to West Antarctica and as 

Africa separated from East Antarctica during the 

initial opening of the Indian Ocean. During this 

time, West Antarctica remained attached to South 

America. According to this reconstruction, ·the 

northern Marie Byrd Land part of West Antarctica, prior to transform faulting, was positioned in 

the present-day Ross Sea opposite north Victoria 

Land. 

SEDIMENTOLOGY OF THE 

HORLICK FORMATION (LOWER DEVONIAN), 

OHIO RANGE, TRANSANTARCTIC MOUNTAINS 

BY LUCY McCARTAN, 

MARGARET A. BRADSHAW1

, AND 

GRAEME AYERS2 

Investigation of the sedimentology and paleoecology of the Horlick Formation was the main 

goal of a 1979-1980 New Zealand expedition to the 

Ohio Range. The study followed the reconnaissance work of previous expeditions, mainly from 

Ohio State University, and was supported by 

grants from the National Science Foundation, the 

New Zealand Antarctic Division, the Canterbury 

Museum. 

The Horlick Formation of Early Devonian age 

consists of 10-50 m of subhorizontal interbedded 

subarkosic sandstone and chloritic shale and mudstone. It is exposed only in the Ohio Range of the 

Transantarctic Mountains between the Ross Ice 

Shelf and Ronne Ice Shelf, at about lat. 85 o S. and 

long. 110°-117° W. 

The Horlick Formation nonconformably overlies 

granitic basement rocks and is overlain by glacial 

and periglacial rocks of Permian age. It contains 

marine fossils, bone fragments and phosphatic 

clasts in several thin beds especially near the base, 

and calcareous concretions and beds of limestone. 

Quartz and lesser amounts of muscovite and 

feldspar are the dominant minerals in the sandstones; biotite is subordinate. Magnetite, epidote, 

sphene, and tourmaline are trace minerals. Secondary calcite is locally abundant in sandstones, and 
authigenic chlorite is ubiquitous in shales and 

mudstones. 

Some beds are laterally persistent for tens of 

meters whereas others contain different facies 

within a few meters. Channels filled with shale or 

sandstone with festoon crossbedding are common. 

Some sandstones are planar bedded or contain interference ripples. Bioturbation has destroyed 

primary structures in many beds. Trace fossils on 

bedding surfaces and burrows suggestive of 

shallow-water deposition are found in several beds. 

Current directions are indicated by crossbedding, channel axes, current lineations, ripple 

marks, direction of sediment accumulation, and 

low-angle crossbeds probably deposited in the 

swash zone of a beach. These indicate that the offshore direction was dominantly southward and 

longshore drift was westward. Northward-dipping 

crossbeds were probably formed on the landward 

side of submerged bars. 

All evidence indicates that the Horlick Formation is an eastward-trending, long, linear body that 

accumulated primarily in a shallow, marginalmarine environment. The source, as indicated by 

the mineralogy, was southward-sloping granitic 

terrane, similar to the underlying basement rocks. 

No marine correlative of the Horlick Formation 

is known from Antarctica, but nonmarine beds 

that may be Lower Devonian are present in Victoria Land. Bradshaw correlates the Horlick Formation with a fossiliferous formation in southwestern New Zealand. The lack of tilting in most 

of the Ohio Range reflects a non-orogenic tectonic 

environment. 

'canterbury Museum. Christchurch, New Zealand 

~aunt Cook National Park, New Zealand. 

SMALL-SCALE MAGNETIC FEATURES 

OF THE POLAR REGIONS 

BY JOSEPH C. CAIN AND DAVE RAY SCHMITZ 

A 29th degree and order spherical harmonic 

model was created from the vector and scalar 

Magsat data taken over the period November 

1979-June 1980 (Cain and others, 1983). The field 

from the first 13 orders was subtracted from that 

computed by the total set of coefficients to 

simulate the trend removal commonly used by 

geophysicists in studying magnetic anomalies. 

The resulting differences were then contoured at 

the Earth's surface to produce maps of magnetic 

"anomalies" in the polar regions. Since the field 

14 

representation is potential, it is thus possible to 

produce maps in any of the commonly used geomagnetic components. At this degree and order, 

features down to about 1,400 km in size may be 

displayed. The intensity at the center of the cells 

depicted for these regions is stronger than those at 

lower latitudes by about the factor of two that one 

would expect from crustal material magnetized in 

the Earth's predominantly dipole field. 

The strongest anomaly noted in this representation is that near the Alpha and Mendeleyev 

Ridges. The vertical (and total) intensity peak is 

near 95 nT at about 150 o W. and 85 o N. Except for 

this positive cell, the remainder of the Arctic 

Ocean area extending into the northern Canadian 

Islands shows weaker negative cells. Greenland is 

covered by two positive cells, each about half the 

intensity of the north polar high, with one in the 

north and the other in the south. 

The strongest anomaly over Antarctica has a 

+65 nT maximum in total intensity (but negative 

in the vertical contours since the vector is reckoned positive downward), and centered over 

Wilkes Land. This feature is surrounded on the 

ocean side by a general negative pattern which 

also intrudes into the Ross Ice Shelf. There are 

strong negative cells over both East and West 

Antarctica separated by a weak positive near the 

geographic pole. A positive feature of comparable 

intensity is seen over Enderby Land. 

There is surprisingly good agreement with the 

patterns published by Behrendt and Bentley 

(1968) from an analysis of surface data, though 

their intensity variations are an order of magnitude greater. 

If the high order and degree components of this 

expansion arise from the crust, the positive areas 

would represent regions where the total magnetization was highest. Possible geologic correlations 

have been investigated by Taylor (1982) for the 

north pole high, by Coles and others (1982) for 

northern Canadian area, and by Ritzwoller and 

Bentley (1982) for the Antarctic. These other 

workers have constructed residual maps derived 

from selections of Magsat data averaged after 

reduction by a 13th degree and order field model. 

They obtain very good agreement with most of the 

features in our representations for the vertical or 

total field, and larger differences in the horizontal 

components. 

There are some questions as to whether these 

features are completely representative of the 
crustal field. It is not likely that the truncation of a 

spherical harmonic expansion gives a clean separation of crustal from core components. Judging 

from the results of Meyer and others (1983) the 

field model to n=13 must also contain a crustal 

contribution. If the source of the high order 

features were in the core, it would imply that they 

were not simple extensions of the lower order 

terms, but of greatly enhanced power. 

There is also the possibility that some of the 

features arise from average external field effects. 

Most of the external currents are field aligned and 

being nonpotential, appear to have little effect on 

the potential expansion. Those other workers who 

have made residual maps from 13th degree potential expansions have carefully selected the data for 

passes containing little obvious current signatures. Their results generally agree with our own, 

especially for the vertical component of field. 

Either the horizontal component of the mostly vertical field-alined currents, or the E-layer ionospheric currents below the spacecraft orbit, could 

contribute to the residual maps. Due to the careful 

selection of the data that entered our model and 

the residual maps of the other workers, these currents are thought to produce only second order 

affects. However, until the currents can be numerically modeled and their magnetic components 

evaluated, their possible contamination cannot be 

evaluated. 

REFERENCES 

Behrendt, J. C., and Bentley, C. R., Gravity and magnetic maps 

of the Antarctic, American Geographical Society Antarctic Map Series, Folio 9, 1968. 

Cain, Joseph C., Muth, Lorant, and Schmitz, Dave, Small scale 

anomalies observed by Magsat, submitted to J. Geophys. 

Res.,1983. 

Coles, R. L., Haines, G. V., van Beek, G. Jansen, Nandi, A., and 

Walker, J. K, Magnetic anomaly maps from 40° N to 83° 

N derived from Magsat satellite data, Geophys. Res. Lett., 

9, 281-284,1982. 

Meyer, J., Hufen, J. H., Siebert, M., and Hahn, A., Investigations of the internal field by means of a global model of the 

earth's crust (to be published), Zeit. fur Geophysik, 1983. 

Ritzwoller, M. H., and Bentley, C. R., Magsat magnetic anomalies over Antarctica and the surrounding oceans, Geophys. Res. Lett., 9, 285-288,1982a 

Ritzwoller, M.H., and Bentley, C. R., Magnetic anomalies over 

Antarctica measured from Magsat, in Oliver, R. L., Jago, 

J.B., and James, P.R., Antarctica Earth Science, Australian Academy of Science, Canberra, 1983. 

Taylor, P., Nature of the Canada Basin: Implications from 

satellite-derived magnetic anomaly data, J. Alaskan Geol 

Soc., 2, 1-8, 1983. 

15 

PALEOMAGNETIC STUDIES IN ANTARCTICA 

BY RICHARD L. REYNOLDS AND 

KARL S. KELLOGG 

The use of paleomagnetism to determine rotations and translations of crustal blocks has contributed to our understanding of the tectonic 

evolution of Antarctica. The units most thoroughly studied paleomagnetically in East Antarctica 

are the Lower Jurassic Ferrar sills and Dufek 

intrusion of the Transantarctic Mountains. Virtual 

geomagnetic poles calculated from these intrusives cluster closely and yield a paleomagnetic 

pole at latitude 54° S., longitude 153° W. The 

corresponding paleolatitude requires about 35 o of 

southward drift for cratonic East Antarctica since 

its separation from Africa in Middle to Late Jurassic time. 

Geologic relationships point to a more complex 

late Mesozoic and Cenozoic tectonic history of 

West Antarctica than of East Antarctica, and 

they lead to speculation that West Antarctica consists of at least three distinct crustal segments or 

provinces having separate patterns of consolidation with the present continent. Paleomagnetic 

data have been obtained from each of the three 

provinces-the Antarctic Peninsula, the Ellsworth 

Mountains, and Marie Byrd Land. 

Paleomagnetic studies of the Antarctic Peninsula have focused on the nature-oroclinal or 

primary?-and age of the pronounced structural 

curvature along the peninsula. Mean paleomagnetic declinations and associated uncertainty 

limits, determined for widespread Andean-type 

Late Cretaceous to Middle Tertiary plutons and 

dikes north of latitude 68 o S., do not require largescale structural rotations, suggesting that any 

oroclinal bending occurred prior to Late Cretaceous time. In contrast, paleomagnetic data from 

rocks of similar type and age from the Orville 

Coast (latitudes 74°-76° S.) are interpreted to indicate a clockwise rotation of the terrane by about 

50°, thus accounting for the curvature of the 

southern Antarctic Peninsula by oroclinal folding. 

For the intervening area of the Lassiter Coast (latitudes 72 o -7 4 o S.), steep paleomagnetic inclinations combined with large uncertainty limits 

preclude assessment of oroclinal bending. Paleomagnetic inclinations from these Andean-type 

intrusives are consistently steep and indicate a 

lack of significant displacement of the Antarctic 
Peninsula relative to the south pole in the past 100 

m.y. 

A number of investigators have postulated that 

a small continental fragment containing the Ellsworth Mountains occupied an original position 

along the Transantarctic Mountains-Cape Fold 

Belt margin of the Gondwana craton. Only preliminary paleomagnetic results from Cambrian argillites in the Ellsworth Mountains are available to 

test this postulate, but the data are consistent 

with such a reconstruction. 

Data from Marie Byrd Land are also sparse. A 

paleomagnetic pole (latitude 36 o S., longitude 116 o 

E.) derived from Early Cretaceous intrusive rocks 

are highly divergent from the Jurassic pole of East 

Antarctica and from the Cretaceous-Tertiary poles 

of the Antarctic Peninsula 

The available paleomagnetic data thus support a 

picture of different tectonic histories for different parts of West Antarctica, but are still too few 

to test complex models. Continued paleomagnetic 

research offers potential for clarifying the tectonic evolution of this enigmatic sector of 

Gondwanaland. 

MEDICAL PROBLEMS OF POLAR REGIONS 

IN THE EARLY 20TH CENTURY 

BY STEVE BOYER, M.D. 

Many diseases occur in specific temporal and 

regional settings. Some occur only until their 

pathophysiology is understood; with the advancement of medical knowledge they are easily prevented and become historical curiosities. These 

diseases may require infectious agents or dietary 

or other habits specific to certain regions. Polar 

explorers of the early 20th century occasionally 

experienced severe prolonged dietary restriction 

which, with the state of medical understanding of 

vitamin metabolism at the time or with their own 

ignorance of disease processes, created the setting 

for some interesting medical problems. 

During the period 1910-1914 at least three polar 

expeditions occurred in which one member of the 

party died from an unknown cause. Detailed descriptions of the slow deaths in the journals of the 

dying or of their companions have enabled physicians to diagnose retrospectively the problen1s 

with varying degrees of certainty. 

During the Australian Antarctic Expedition 

16 

(1911-1914), Douglas Mawson, Xavier Mertz, 

and Belgrave Ninnis made a sled journey of several hundred miles with dogs into King George V 

Land. The setting for dietary restriction was 

created when Ninnis fell into a crevasse with the 

food sled. Mawson and Mertz then began their 

return to the coast, working the remaining dogs 

to exhaustion and starvation before eating their 

remains, including the livers. Descriptions in 

their journals of loss of epithelial tissues (hair, 

skin, bowel lining) and our current understanding 

of the concentration of vitamin A in predators' 

livers and its metabolism in humans have led to a 

relatively certain diagnosis of hypervitaminosis 

A as the cause of death of Mertz and the near 

demise of Mawson. 

On the second British South Pole Expedition 

(1910-1913), R. F. Scott and his four companions 

reached the pole January 17, 1912. The dietary 

restriction inherent in a man-hauling polar sled 

journey was exacerbated by Scott's last-minute 

decision to include Bower in the polar party, requiring that five men live on rations intended for 

four. In addition to the caloric deficiency, the diet 

was devoid of vitamin C. On the return, Evans 

died at the base of the Beardmore several days 

after a fall into a crevasse. Again, detailed journal 

descriptions of his medical course enable us to 

create a differential diagnosis, among the likeliest 

causes of death being a subdural hematoma from 

minor trauma, a complication of scurvy (vitamin 

C deficiency). 

While these Antarctic expeditions were taking 

place, Bernhard Hantzsch, a German zoologist, 

was leading a party of explorers into the Foxe 

Basin coast of Baffin Island in the Canadian Arctic. Dietary restriction this time was created by 

the sinking of their ship in Cumberland Sound, 

despite which they set off in the spring of 1910 to 

explore the coast to the north. Returning a year 

later they were forced to live on polar bear meat 

which Hantzsch preferred to eat frozen, raw. He 

did not realize the symptoms he accurately described in his own journals were those of trichinosis from which, there is little doubt, he died. 

With a clear understanding of the pathophysiology of each of these illnesses, they have been 

eliminated as problems of modem expeditions, 

but so too has the remoteness of the polar regions 

been eliminated. These case histories are of great 

medical and historical interest. 
MAR5-ANALOG STUDIES IN WRIGHT AND 

VICTORIA VALLEYS, ANTARCTICA 

BY E. C. MORRIS AND H. E. HOLT 

During the 1971-72 field season, 1,300 photographs were taken of various geologic features in 

Victoria and Wright Valleys for comparative 

analysis with the pictures expected to be returned 

from the Viking Mars Mission in 1976. The cold 

dry weathering environments of the ice-free 

valleys of Antarctica provide one of the best terrestrial analogs of surface conditions on the 

planet Mars. The features photographed in 

Wright and Victoria Valleys, such as frozen 

dunes, patterned ground, various rock weathering phenomena, ventifacts, felsenmeers, tors, and 

desert pavements, have proved to be valuable in 

understanding features seen in the Viking 

photographs. 

The scene at the Viking landing sites is reminiscent of the rock-littered landscape of Wright and 

Victoria Valleys. The Viking Lander 1 pictures 

show a surface strewn with rocks in the centimeter to meter size range. Between the rocks, the 

surface is blanketed by very fine grained ( < 100 

mm) material that has been sculptured by martian winds into "tails" behind the rocks. Light 

and dark drifts of this material are distributed 

across the surface; these drifts probably are remnants of a thick blanket of very fine grained 

material that once covered the area and was subsequently eroded by wind. 

The Viking 2 landing site is a flat boulderstrewn landscape that is part of the vast plains 

which occupy much of the northern hemisphere of 

Mars. Large blocks are more numerous here than 

at the Viking 1 site and are almost monotonous in 

their similarity to one another. Most of these 

blocks are subangular, equidimensional, and have 

numerous pits or holes a few millimeters to a few 

centimeters across that impart a sponge-like appearance to their surfaces. The interblock areas 

are composed of fine-grained material and 

patches of pebbly fragments; in places, this finegrained material is banked into small drifts between blocks. The surface has a windswept or 

scoured appearance, and some boulders appear to 

stand on pedestals of fine-grained material. In 

many of the interblock areas the fine-grained 

material forms a discontinuous crust that breaks 

into platy fragments. A series of interconnecting 

17 

troughs, typically 1 m wide and 10 to 15 em deep, 

are visible at the Lander 2 site. These troughs 

form a polygonal network that probably developed from contraction either by cooling of lava or 

from thermal expansion and contraction of frozen 

ground. 

The features seen in the Viking pictures that 

are analogous to those photographed in Antarctica include: armored pavements, wind tails (erosional and depositional features that record wind 

direction), ventifacts, frost shattering, and patterned ground. 

AN ISOTOPIC AND CHEMICAL STUDY OF 

LAKE VANDA AND DON JUAN POND, 

ANTARCTICA 

BY IRVING FRIEDMAN, 

ATHOL RAFTER1, AND GEORGE SMITH 

Temperature measurements made in Lake 

Vanda and in the lake subbottom sediments show 

that the high temperatures in the lake are not due 

to geothermal heat flow, but are probably trapped 

solar energy as suggested by Wilson. 

On the basis of Sr:87 /

86 ratios the salts in Lake 

V anda can be derived by a mixture of 58% weathered rock plus 42% from sea water or precipitation. Loss of efflorescences high in sodium, 

potassium and magnesium by high winds can yield 

the salt compositions present in both Lake V anda 

and Don Juan Pond. 

From isotopic data on deuterium, 0 18, C13, Sr:87

/

86, 

S34 as well as from chemical data on Lake V anda 

waters, interstitial brines contained in the subsurface sediment and C14 dates we propose the following lake history: 

(1) Fiord. 

(2) Uplift caused isolation of Wright Valley from 

the Ross Sea 

(3) Some of the sea water flushed out by glacial 

meltwater. 

(4) Glacial melt water flowed into the basin. Soluble salts, formed by weathering of local bedrock and salt contributed by original sea 

water and by precipitation slowly accumulated in the Lake. The climate cooled and inflow was less than evaporation. The lake 

desiccated. The final desiccation yielded a 

CaC12-NaCl brine. Sodium, potassium, and 

maoonesium chloride sulfate and carbonate 

minerals formed an efflorescence that was 
blown away, leaving a brine enriched in 

calcium chloride. 

(5) Crystals of CaC12 • 6H20 formed, enriched in 018 

but depleted in deuterium relative to the 

precursor brine. 

(6) A brief climatic warming occurred 2,600±100 

years ago resulting in the filling of the basin 

to the high stand now preserved as high 

beach levels. 

(7) This episode was short lived, and a climate 

cooler than the present caused the lake to 

shrink to a low level, or to desiccate 

completely. 

(8) Another climatic warming occurred about 

1,200 years ago filling the basin to its present 

level. The initial warming was warmer than 

the present, since the inflow shows evidence 

of possible polar plateau glacier inflow or increased melt water from valley glaciers. 

1

lnstitute for Nuclear Studies (DSIR), Lower Hutt, New Zealand 

CLIMATIC SIGNIFICANCE OF 

LACUSTRINE DEPOSITS AROUND LAKE VANDA 

AND DON JUAN POND, ANTARCTICA 

BY GEORGE I. SMITH AND IRVING FRIEDMAN 

Geologic reconnaissance in the valleys surrounding Lake Vanda and Don Juan Pond in 

Wright Valley, Antarctica, was carried out over a 

. period of several days during November 1973. It 

was a byproduct of the drilling program at Lake 

V anda (DVDP 4) carried out during the Dry Valley 

Drilling Project, sponsored in part by the U.S. National Science Foundation. The reconnaissance included observations and sampling of lacustrine 

sediments exposed around both lakes. Erosional 

shorelines around Lake V anda have been reported 

by several workers; lake sediments, also described 

previously, lie well above the present lake level and 

consist of thick layers of sand and fine gravel that 

rest on older coarse gravels. The lacustrine 

deposits around Don Juan Pond are silts that had 

not been described prior to our earlier note (Smith 

and Friedman, 197 4). 

Large volumes of solid H20-ice-exist on the 

flanks and ends of most closed basins in the Dry 

Valley area, and a small amount of this ice melts 

annually to supply the lakes. The sizes of most 

closed-basin lakes in these areas are limited, 

therefore, by the amount of liquid H20 available 

18 

from their drainage or ground-water supply rather 

than by the total amount of H20. Thus, it is the intensity and length of the warm period during the 

summer months, acting on the ice areas at lower 

elevations, that control the amount of melting and 

the sizes of lakes in the Dry Valley area 

Expansion of Lake V anda as a result of warmer 

temperatures was suggested by Nichols (1962), 

but he related the lake rise to the warming that 

caused the retreat of Trilogy-age glaciers which 

had been dated as more than 7,000 yr B.P. The 

C14 dates on algae from around the edges of 

Lake V anda suggest that its expansion occurred 

2,000 to 3,000 yr B.P.It seems more likely that the 

expansions of Lake V anda and Don Juan Pond 

were the result of a more recent episode of warming, but it may not be documented by the exposed 

evidence of glacial retreats. The sizes of the present glaciers are presumably in equilibrium with 

the present climate, and we suspect the enlarged 

lakes are correlative with major glacial retreats 

that deposited moraines in areas now re-covered 

by ice. 

The expanded lakes, therefore, seem to indicate 

a period, possibly only a few centuries long, 2,000 

to 3,000 years ago, characterized by slightlywarmer-than-present summers; they raised the 

snowline, increased the volumes of ice that melted 

annually from the lower parts of the glaciers and 

ice-cored debris flows, and caused the glaciers to 

retreat and the lakes to expand. When the summers cooled and the snowline again lowered, little 

or no ice remained at the levels where summer 

melting could occur, and at first the lakes received 

almost no runoff and nearly desiccated, as inferred 

from other evidence by Wilson (1964). Eventually, 

however, the surplus ice accumulating above the 

new snowline would have been transported by glaciers far enough down into the valleys for summer 

melting to again produce sufficient runoff to 

nourish lakes of the sizes and levels we now find. 

PROGRAM FOR MAPPING ANTARCTICA 

BY PETER F. BERMEL AND 

CHARLES E. MORRISON 

Mapping has been such an integral part of most 

nations' programs in Antarctica over the past 

quarter century that it may come as a surprise to 

learn that a program for Antarctic mapping was 
not among the activities recommended for the International Geophysical Year (IGY) in 1957-58. 

When the decision was made to pursue a post-IGY 

long-range Antarctic research program, the 

lessons of the IGY left no doubt that mapping 

must be included. 

In the case of the United States, the Antarctic 

cartographic effort has been located at the U.S. 

Geological Survey (USGS), funded by the National 

Science Foundation as part of the U.S. Antarctic 

Research Program (USARP). The USGS has focused its mapping on West Antarctica and the 

Transantarctic Mountains to support the requirements of USARP. It has sent field parties to Antarctica every year since 1957 to establish geodetic 

control and has worked closely with U.S. Navy 

Squadron VXE-6 to acquire mapping-quality 

aerial photographs. 

The program has been very productive, resulting in over 90 1 :250,000-scale topographic reconnaissance maps of West Antarctica and the Transantarctic Mountains. Other products include 

1:50,000-scale topographic maps, 1:500,000-scale 

sketch maps, 1:1,000,000-scale topographic maps 

and shaded-relief reconnaissance maps, as well as 

satellite image maps at several mapping scales. 

Future needs can be met by: 

1. A primary series at 1:250,000 scale covering all 

mapworthy features in the area of West Antarctica and between longitudes 150° E and 

180° E. 

2. IMW sheets at 1:1,000,000 scale prepared from 

published 1:250,000-scale maps. 

3. Satellite image maps at scales of 1:250,000 and 

smaller. 

4. Larger scale (1:100,000 and larger) maps of 

areas of special interest where greater detail is 

warranted. 

The USGS effort in support of NSF's USARP is 

a remarkable story unequaled in An~tica. Over 

100 National Mapping Division personnel have 

worked there in the field, and the challenge of "the 

ice" continues to be a lure to the candidates applying to work on the mapping projects. 

THE USE OF SATELLITE TECHNOLOGY IN 

THE SEARCH FOR METEORITES IN ANTARCTICA 

BY TONY K. MEUNIER 

Until 1969 only four meteorites had been 

recovered from Antarctica, each during an 

19 

overland traverse. During the 1969-70 field 

season, however, Japanese scientists discovered 

nine stony meteorites in a blue-ice area of the 

Queen Fabiola (Y amato) Mountains and suggested 

that Antarctica might prove to be an excellent 

source of meteorites. In 1973, Prof. William A. 

Cassidy, a meteoriticist at the University of Pittsburgh, reached the same conclusion and proposed 

a U.S. program to search for meteorites in blue-ice· 

areas accessible by helicopter from McMurdo Station. Approximately 5,400 meteorite fragments 

have now been recovered from Antarctica, mostly 

from blue-ice areas, especially where the normal 

flow of glacier ice is impeded or stopped; hence 

blue ice is of special significance in the search for 

more meteorites. 

Delineation of surficial blue-ice patches in Antarctica north of about 81 o S. latitude became 

possible after the launch of the first Landsat 

spacecraft in July 1972 by providing higher resolution satellite images of various parts of Antarctica. Beyond 81 o S. latitude advanced very high 

resolution radiometer (A VHRR) images from the 

NOAA series of weather satellites can be used to 

identify areas of blue ice, although the 1-km pixel 

size of the image provides 10 times less detail than 

that available from Landsat MSS. This resolution 

proved to be adequate in detecting the relatively 

large blue-ice areas, however. Landsat 1, 2, and 3 

MSS have a pixel (picture element) size of about 80 

m. The images are usually acquired in four spectral 

bands: MSS band 4, 0.5 to 0.6 em; MSS band 5, 0.6 

to 0.7 em; MSS band 6, 0.7 to 0.8 em; and MSS 

band 7, 0.8 to 1.1 em. In the identification of blueice areas, MSS bands 6 and 7 are similar, with 

band 7 somewhat better than MSS band 6. MSS 

band 5, however, is best in areas of bedrock exposure, because blue ice and rock outcrops usually 

have a similar spectral response. 

Various types of satellite data were used during 

the 1982-83 austral summer field season on Prof. 

Cassidy's United States Meteorite-Search Project 

in Antarctica, in the isolated, unmapped polar 

plateau region called the "Far Western Ice 

Fields.'' In the past, a dead-reckoning type of 

traverse would normally have to be employed for 

daily trips to meteorite-collecting areas. The field 

party used a 1:250,000-scale Landsat 1 image 

(1200-20293; 8 February 1973) of the meteoritesearch area for the planning and execution of 

oversnow traverses. Although the polar plateau on 
a continental scale is a relatively flat, featureless 

·area, from a regional perspective, as in the 60 km2 

"Far Western Ice Field," there is significant 

topographic relief that resembles an undulating 

ridge- and valley-type terrain. This made local 

traverses very difficult to negotiate by line-ofsight techniques. Landsat images permitted the 

field party to intermittently check their positions 

by locating and following features visible on the 

images, such as fim patches. Hence, the use of 

Landsat images was instrumental in successfully 

completing a number of difficult traverses in both 

the "Far Western" and "Far Northwestern Ice 

Fields.'' 

Satellite tracking data were also used, for the 

first time, to accurately map meteorite finds by using a portable Magnavox 1502 Satellite Tracking 

Positioning System. This state-of-the-art geoceiver, on loan from the Bureau of Land Management, proved to be very effective in these remote 

expanses of snow and ice. With the Magnavox 

1502, a base line consisting of five geodetic positions over a 30 km X 2 km collecting area was 

established. At the site of each meteorite find, the 

meteorite identification number was written on a 

flag implanted in the ice. After an area was systematically searched, and all the meteorites had 

been collected, the angles and odometer distances 

between the base station and the numbered flags 

were recorded. Final mineralogical identification of 

each specimen by NASA's Johnson Space Center 

along with the acquired control will result in a 

thematic map of the "Far Western Blue Ice Field" 

collecting area. These are the first controlled 

survey points ever established in this remote area. 

In addition, these positions can be reoccupied in 

the future to measure the change in the x, y, and z 

parameters. Determining the rate of ice movement 

in this area will be an important contribution to 

the understanding of the mechanisms which lead 

to the concentration of meteorites at blue-ice 

locations. 

Aerial photographs were also used to help select 

areas for potential collecting sites. All the five 

blue-ice areas, selected from satellite images and 

aerial photographs for field investigation, were 

found to contain concentrations of meteorites. 

This was totally unexpected and highly significant. The use of satellite technology proved to be 

effective, and its continued use will be an important tool in the systematic search for and recovet"y' 

of meteorites in Antarctica. 

20 

GLACIOLOGICAL AND GEOLOGICAL STUDIES 

OF ANTARCTICA WITH 

SATELLITE REMOTE SENSING TECHNOLOGY 

BY JANE G. FERRIGNO, 

RICHARDS. WILLIAMS, JR., 

C. SCOTI SOUTHWORTH, AND 

TONY K. MEUNIER 

The Satellite Glaciology Project of the U.S. 

Geological Survey has been using remotely sensed 

data to support a variety of glaciological and 

geological investigations in Antarctica. A significant attribute of the Landsat image is that it contains the precise time of acquisition, providing a 

method for making "time-lapse" measurements of 

the dynamics of the coast of Antarctica. Two 

Landsat images, 1185-13530 and 2022-13582, acquired on 24 January 1973 and 13 February 1975, 

respectively, were used to determine the velocity 

of the terminus of the Pine Island Glacier, a tidal 

outlet glacier on the Walgreen Coast, West Antarctica. During the 7 50-day interval, the terminus 

of Pine Island Glacier moved about 4.5 km at an 

assumed average velocity of 6 m per day. 

Landsat images of the Amery Ice Shelf and terminus of the Lambert Glacier were combined as a 

1:500,000-scale uncontrolled image mosaic to 

serve as a base for compilation of 1- and 5-m contours of the shelf derived from 45 Seasat radar 

altimeter traverses. The successful experiment 

reemphasized the fact that satellite image mosaics 

and maps can be effectively used as the compilation base for various types of geological, glaciological, and geophysical data. 

Preliminary research with Charles W. M. Swithinbank has established that Landsat images of 

Antarctica can be used to prepare 1:1,000,000-

scale planimetric maps of coastal areas, bedrock 

exposures, and blue-ice areas of Antarctica. A 

more accurate delineation of: (1) the coast of Antarctica, including the type of coast (bedrock, 

floating ice, grounded ice, outlet glacier terminus); 

(2) areas of bedrock; (3) areas of blue ice; and (4) 

plotting of other glaciological features (medial 

moraines, crevasse areas) will result from completion of this effort. The accurate location of blue-ice 

areas is important to the international program to 

recover meteorites from Antarctica. 

Preliminary research was carried out to determine whether digital processing of Landsat multispectral scanner (MSS) images of rock outcrops in 

Antarctica could lead to a method of mapping rock 
units from nunatak to nunatak on the basis of 

their spectral reflectance characteristics. The 

BorgmassivetJ Ahlmannryggen region of western 

Queen Maud Land, East Antarctica, located within the Iron Metallogenic Province, was targeted 

for analysis because of the availability of 

1:250,000-scale reconnaissance geological maps 

(printed on a Landsat image mosaic base) published by the South African Scientific Committee 

for Antarctic Research. 

USGS PROGRAM AT THE SOUTH POLE 

BY THOMAS EDMONDSON AND KATHY COVERT 

The United States Geological Survey, National 

Mapping Division, has sent 11 consecutive winterover teams to the South Pole. This continuing effort has been in support of two ongoing projects. 

The first project, USGS Doppler Satellite Tracking, was initiated in 1972. Data are collected from 

overflights of Navy navigation satellites, transmitted to the United States for further data reduction, and then shared with other investigators for 

detailed analysis. The second project is the USGS 

Antarctic Seismic Project. In 1974 new seismometers were installed at the South Pole. The seismic 

station is now part of the Worldwide Standardized 

Seismograph Network because of its unique location in the Southern Hemisphere and an important 

source of seismic data. The USGS is responsible 

for relocating and remonumenting the true geographic South Pole. 

This presentation will be a summary of the objectives and accomplishments of the ongoing 

USGS projects at Amundsen-Scott South Pole 

Station, Antarctica. 

MODELING THE MOVEMENT AT THE 

POLAR ICE CAP AT THE SOUTH POLE 

BY THOMAS HENDERSON 

The United States has continuously occupied 

the South Pole since the International Geophysical Year in 1957-58. The original base was 

approximately 1 km from the Geographic South 

Pole and was used until the 197 4-75 season. Snow 

drift accumulation over the old facility forced the 

construction of a new station about 400 m from 

the Pole. Manned since 1975, it features a large 

geodesic dome that shelters the main buildings. 

A number of astronomic observations were 

21 

made by various Pole parties between 1956 and 

1970 to establish the position of the old base with 

respect to the Pole. These were also used to estimate the rate and direction of movement of the 

polar ice cap. In 1970, Bill Chapman and Bill Jones 

of the U.S. Geological Survey, National Mapping 

Division, published mathematical models describing the movement. The latitude-longitude positions calculated from the astronomic observations 

were first converted to an X-Y rectangular coordinate system, the Y -axis of which was coincident 

with the average longitude of the observation positions (24 o 40' W.). The equations of straight lines 

were then fit by least squares to the plots of X versus time and Y versus time. The models indicated 

a movement of 19m per year parallel to the 37° W. 

meridian. 

The U.S. Geological Survey began sending 

winter-over teams to South.Pole in 1972, primarily 

to man geodetic satellite tracking receivers. This 

continual tracking results in precise position 

measurements for the tracking antenna site. 

A substantial amount of position information 

has been collected for the current site since it was 

established in 1975. The coordinates computed 

from satellite data represent a significant improvement in both accuracy and precision over astronomic positions. By analyzing the Doppler frequency shift curves received from passing 

satellites, ground points are resolved to within 1 m 

of their true coordinates. This information, then, 

provides a more accurate data base for modeling 

the ice movement. 

During the winter of 1982, the author set about 

to generate new models based on the satellite-. 

derived positions from 1975-81. Coordinates are 

provided in a geocentric X-Y-Z reference system, 

so the data are immediately usable in rectangular 

plots. Compensation is made for the slight wobble 

in the Earth's polar axis when reducing to the 

geocentric system to eliminate this source of comparison difference. Again, linear least squares fits 

were made to the plots of X versus time and Y versus time. The resulting three models fit the data 

with a standard deviation of 0.9 min both X and 

Y. They indicate a movement of 10 m per year 

parallel to the 41 o 11' W. meridian. 

The models enable the prediction of the Pole position for a future date. Since the new antenna site 

is tied into a local survey network, the physical 

marking of the Pole for that date is reduced to a 

simple surveying operation. 
ARCTIC PROGRAM 

CONVENER: G. GRYC 

HISTORY OF U.S. GEOLOGICAL SURVEY 

GEOLOGIC EXPLORATION AND 

MINERAL-RESOURCE EVALUATION, ARCTIC 

ALASKA 

BY GEORGE GRYC AND ROBERT M. CHAPMAN 

The history of geologic exploration, mineral 

resource evaluation, and topographic mapping in 

Alaska's Arctic region is well chronicled and 

documented in U.S. Geological Survey (USGS) 

publications and activities. Although several 

recorded expeditions traversed parts of the region 

before 1900, the USGS party in 1901, headed by 

W. J. Peters and F. C. Schrader, was the first to 

map in some detail the geologic structure and 

stratigraphy and topography along a transect 

from the Brooks Range to the Arctic coast. Their 

report, published in 1904 as USGS Professional 

Paper 20, named and described the Lisburne Formation, of Mississippian and Pennsylvanian age 

and described the sequence and structure of the 

Cretaceous rocks, both destined to become major 

petroleum exploration targets in Arctic Alaska. In 

USGS Professional Paper 109, published in 1919, 

E. de K. Leffingwell reported on the oil seepages at 

Cape Simpson, described and named the Sadlerochit Group and Shublik Formation of Prudhoe 

Bay fame, and described and mapped the geology 

of the Canning River region, now included in the 

Arctic National Wildlife Refuge. Leffingwell's 

description of the ice wedges and other frozenground phenomena along the Arctic coast and his 

proposed explanation for their formation remains 

a classic reference for students of permafrost. A 

knowledge of permafrost and its applications to 

engineering and exploration projects is essential to 

successful operations in the Arctic. 

On the basis of these early reports, President 

Harding set aside the Naval Petroleum Reserve 

No. 4 (NPR-4) in 1923, and the U.S. Navy requested that the USGS map and report on the 

geology and potential resources of the region. 

From 1923 through 1926, eight USGS parties 

crossed the Brooks Range and the NPR-4 along 

many of the major rivers. Their findings were 

published in 1930 in USGS Bulletin 815, in which 

P. S. Smith and J. B. Mertie, Jr., concluded that 

22 

the essential geologic conditions for petroleum accumulation were present, but cautioned would-be 

prospectors against the adverse geographic factors and the consequent high development costs. 

They recommended that the next step should be 

drilling in the Cape Simpson area, followed by 

geologic studies and more drilling in other areas 

that appeared favorable. 

However, very little additional exploration was 

conducted on the North Slope until 1944, when a 

wartime effort (1944-53) was initiated by the U.S. 

Navy to further evaluate the petroleum resources 

of what was then popularly referred to as Pet-4. 

Again the USGS was asked to undertake the geologic aspects of the work. The Pet-4 program 

established the surface and subsurface framework 

geology of the North Slope and proved the feasibility of operating a modem-oil exploration program 

in the Arctic. All the technical results were published in USGS Professional Papers 301 through 

306. 

Stimulated by a major oil discovery in Cook Inlet in 1957 and building on the knowledge base and 

know-how provided by the Pet-4 program, the oil 

industry took up the search for oil in the Arctic 

and 10 years later discovered the largest field in 

North America at Prudhoe Bay, east of Pet-4. 

The USGS, partly in cooperation with the U.S. 

Navy, continued its work in northern Alaska during this period, particularly in the Arctic foothills 

and Brooks Range provinces. While examining 

and sampling oil shales in northern Alaska in 

1968, I. L. Tailleur collected stream sediment 

samples in the Red Dog area of the DeLong Mountains. Chemical analyses indicated 10 weight percent Ph and thus provided the first hint of sulfide 

mineralization in the western Brooks Range. Follow-up by other agencies and industry has now 

defined a ''world class'' belt of stratabound sulfide 

deposits that could provide the Nation with a 

10-year supply of zinc and a 5-year supply of lead 

at present consumption rates. On the basis of 

limited Pet-4 data, F. F. Barnes in 1967 estimated 

the coal resources of northern Alaska at about 130 

billion tons. More recent work by J. E. Callahan 

and others suggests a hypothetical resource of as 

much as 3 trillion tons of low-sulfur subbituminous coal. New concepts and syntheses of the geology of Arctic Alaska and the adjacent continental 

shelves continue to be formulated and published 

by USGS geologists. 
USGS studies in the Brooks Range and on the 

North Slope have been stimulated and funded in 

response to a steady stream of national programs 

and needs, such as the trans-Alaska oil and gas 

pipelines, the Alaska Mineral Resource Assessment Program (AMRAP), the offshore leasing program, and the recently concluded program mandated by the Naval Petroleum Production Act of 

1976. This act transferred the responsibility for 

Pet-4 to the Secretary of the Interior and renamed 

it the "National Petroleum Reserve in Alaska" 

(NPRA). The USGS was directed to (1) continue 

the exploration program begun by the U.S. Navy 

in 197 4; (2) continue to operate and maintain the 

Barrow gas fields, which are virtually the sole 

energy source for the growing community of Barrow; (3) complete a cleanup and rehabilitation program begun by the U.S. Navy; and (4) participate 

in various resource surveys (the so-called 1 05(c) 

studies) and the petroleum resource assessment, 

(the 105(b) studies). All of the resulting technical 

data are being released by the Survey, utilizing the 

National Oceanic and Atmospheric Administration Data Center in Boulder, Colo., and through 

regular USGS map and book publications. 

The USGS's experience in Arctic Alaska in 

gathering geologic and geophysical data, providing new concepts and syntheses of these data, and 

assessing resources is an excellent example of the 

scientific accomplishments that are possible and 

enhanced by working closely with other agencies 

and industry. It also illustrates the long leadtime 

needed to build a knowledge base leading to discovery and development. This knowledge base 

must be communicated on a timely basis and be in 

the public domain so that all concerned have access on an equal basis. Old data must be integrated with new findings and periodically 

reviewed to see what new concepts and interpretations may result. Although some programs may 

have narrowly defined objectives, spinoffs in other 

areas and scientific disciplines and serendipitous 

discoveries are virtually certain, especially in such 

a frontier region as the Arctic. 

TECTONICS OF ARCTIC ALASKA 

BY I. L. TAILLEUR, I. F. ELLERSIECK, AND 

C. F. MAYFIELD 

[No abstract] 

23 

TECTONIC EVOLUTION OF THE 

ARCTIC CONTINENTAL MARGIN IN THE 

BEAUFORT AND CHUKCHI SEAS-EVIDENCE 

FROM SEISMIC REFLECTIONS 

BY ARTHUR GRANTZ AND S. D. MAY 

Multichannel seismic-reflection profiles in the 

northern Chukchi and Beaufort Seas suggest that 

three pulses of rifting created the first-order 

geologic structures and localized the sedimentary 

basins of the continental margin north of Alaska. 

A Late Triassic-Early Jurassic pulse isolated shelf 

deposits of the Mississippian to Triassic Arctic 

Alaska Basin from their sourceland in the present 

area of the Arctic Ocean and created the eastwesterly trending Dinkum graben. This graben, 

which underlies the eastern half of the Alaskan 

Beaufort shelf, contains 2 to 4 km of inferred 

Jurassic to Paleogene clastic rocks. 

Late Neocomian to Albian rifting completed the 

process of continental breakup and formed the 

Canada Basin of the Arctic Ocean by sea-floor 

spreading. From 4 to 10 km of submarine-fan and 

abyssal-plain deposits partially fill this ocean 

basin. Clastic sediment from southern sourcelands 

overstepped the newly rifted margin by Albian 

time and prograded the present continentalterrace sedimentary prism. This prism, more than 

13 km thick, is dominated structurally by growth 

faults and rotational megaslumps; off northeastem Alaska it contains large syndepositional 

diapiric-shale ridges and Quaternary detachment 

folds. 

Both late Neocomian(?) and latest Cretaceous or 

early Paleogene pulses of rifting between Wrangell 

Island and the Chukchi Continental Borderland 

appear to have thinned the continental crust into 

which the North Chukchi Basin subsided. The 

earlier pulse is recorded by marked basinward 

thickening of Cretaceous strata, and the later one 

by numerous antithetic faults and foundered fault 

blocks in the Cretaceous strata. Sediment in the 

basin is more than 12 km thick. Because the basin 

underlies the shelf only adjacent to the borderland, 

these contiguous features may be tectonically 

related. 
. THE ARCTIC PLATFORM IN THE NATIONAL 

PETROLEUM RESERVE IN ALASKA-DEPOSITION, 

DEFORMATION, AND PETROLEUM POTENTIAL 

BY C. E. KIRSCHNER 

The National Petroleum Reserve in Alaska 

(NPRA) covers an area of 93,240 km2 or about half 

of the Arctic slope in the west-central part of 

northern Alaska. This paper outlines the major elements of the geology and a few aspects of the 

stratigraphic history and structural development 

of the Arctic platform that have a significant bearing on the oil and gas potential of the region. The 

Arctic platform was originally defined as a preAlbian tectonic feature that occupied the northern 

part of the present coastal plain and the adjacent 

area of the Arctic Ocean. I view the area of the 

platform as extending southward in the subsurface across the NPRA at least to the north front of 

the Brooks Range. 

The stratigraphy is subdivided into three major 

Phanerozoic sequences: the Franklinian, the 

Ellesmerian, and the Brookian. The Franklinian 

sequence, of pre-Mississippian age, consists 

primarily of metamorphosed sedimentary rocks 

that are complexly deformed and thus constitute 

economic basement for petroleum exploration. 

The Ellesmerian sequence, of Mississippian to 

Early Cretaceous age, consists of clastic, bioclastic, and associated sediment in part derived 

from a northern provenance (Barrovia) that was 

partly rifted away by the end of Neocomian time. 

In the following discussion, this sequence is subdivided into three distinct subsequences: lower, 

middle, and upper. The lower Ellesmerian subsequence, of Mississippian to Early Permian age, 

consists of nonmarine clastic rocks overlain by 

marine-sheH bioclastic strata that fill grabens and 

overlap adjacent horst blocks and uplifts on the 

Franklinian basement. This subsequence is very 

thick in the riftlike graben lows and thins rapidly 

by time-transgressive onlap in a northerly 

direction. 

The middle Ellesmerian subsequence, of Late 

Permian and Triassic age, includes fluvial to 

marine-sheH clastic and bioclastic strata that form 

a sheetlike package across the Arctic platform. 

This subsequence is relatively thin and, like the 

underlying lower Ellesmerian subsequence, is also 

time transgressive northerly on the platform. The 

distribution of sandstone facies dictates a prox24 

imal northerly-provenance terrane. There are no 

similar sheH deposits on the Arctic platform in 

post-Triassic time. These sandstone and bioclastic 

limestone beds are the reservoirs for the giant 

Prudhoe Bay oilfield east of the NPRA, where 

these reservoirs are sealed by the overlapping 

pebble-shale unit of Neocomian age. Only the Barrow gasfields in the NPRA have a similar tectonostratigraphic setting. The early and middle Ellesmerian reservoir beds in the NPRA are interpreted 

not to form traps because the rocks are time transgressive on the platform, and so petroleum probably migrated updip with the strandline facies. 

The upper Ellesmerian subsequence, of Jurassic 

and Early Cretaceous (Neocomian) age, includes 

marine shale, minor sandstone, and mudstone that 

form a blanketlike package across the platform. The 

distribution of sandstone facies and southerly prograding foreset beds in the Kingak Shale is interpreted to define a distal northerly provenance that 

ceased to supply detritus to the platform by late 

Neocomian time. Other workers have stated that 

the upper Ellesmerian rocks were deposited in a 

shallow-marine sheH environment. However, paleontologic bathymetric indicators, core lithologies, 

electric-log characteristics, and seismicstratigraphic interpretation all suggest a deepwater basinal environment in which suspended-load 

or turbidite processes were involved. The upper 

part of the Ellesmerian sequence is interpreted to 

have been deposited in a southerly, southwesterly, 

and southeasterly prograding turbidite fan complex. The sandstone beds that make up the potential reservoir rocks are composed of turbidite channel sandstone that commonly fines upward and of 

suprafan sandstone sequences that are cyclic and 

thicken upward. Following this line of reasoning, 

the Kuparuk River oilfield reservoirs are interpreted to be turbidite sandstone in a combined 

structural-stratigraphic trap in which the pebbleshale unit forms the overlying stratigraphic seal. In 

the northwestern part of the NPRA, significant gas 

shows were penetrated in the Tunalik well within a 

setting that may be similar to the Kuparuk field. 

The concept of turbidite reservoirs enhances the 

potential for primarily stratigraphic entrapment, 

although these reservoirs may also consist of lowporosity and low-permeability fine-grained silty 

sandstone with low producing capabilities. Furthermore, oil shows are more common east of the Meade 

arch, whereas gas shows are more common west of 

the arch. The latest Neocomian beds are distal 
pyritiferous shale, rich in organic material, and 

mudstone deposits. Seismic stratigraphy suggests 

that these beds were derived from the south in the 

Brooks Range provenance and indicates that "flip" 

in provenance to the Arctic platform was completed 

by the end of Neocomian time. 

The Brookian sequence, of Early Cretaceous to 

Holocene age, includes the latest Neocomian 

strata and all post-Neocomian formations. The sequence consists mainly of thick flysch and molasse 

deposits flushed from the rising Brooks Range orogen and dumped into the Colville foredeep to prograde northward and eastward across the Arctic 

platform and the present Barrow arch. Lowermost 

Brookian sequence rocks of the Torok Formation 

are deep-water prodelta turbidites deposited on 

the platform and over the Barrow arch before 

uplift during post-Albian time. The turbidite sandstone may offer reservoir targets in a variety of 

structural and stratigraphic settings. Upper 

Brookian sequence rocks of the Nanushuk and Colville Groups are delta-plain sandstone and shale 

that are marine in the east and nonmarine and coal 

bearing in the west. They offer reservoir sandstone 

targets that are generally at shallow depths and on 

small structures, so that the economics of these 

plays may not be attractive unless a local need is 

developed. 

The Arctic platform province is defined by seismic and well data beneath the Arctic Coastal 

Plain. The platform dips regionally south beneath 

the northern foothills province and is interpreted 

to continue to dip south beneath the southern foothills province at least as far as the north front of 

the Brooks Range thrust belt. The platform also 

dips regionally west and east from the northsouth-trending Meade arch in the central part of 

theNPRA. 

The northern foothills province is a broadaxshaped wedge incorporating a wrinkled-carpet pattern of detachment folds in Brookian rocks that 

overlie the regionally south-dipping homoclinal 

Ellesmerian sequence. 

The southern foothills province encompasses 

two contrasting styles of complex structure. Subparallel to the north front of the Brooks Range 

thrust belt, the structure, in mainly Lower Cretaceous shale and graywacke, involves very complex 

bed crenulation, isoclinal folding, and thrust 

faulting. Northwest of this band, broad ridgeforming bathtub-shaped synclines, which appear 

to float on a shale substrate (Torok Formation), 

25 

are separated by long narrow faulted diapiric anticlines. Seismic data do not appear to define 

evidence of the style of frontal thrust folds in 

Ellesmerian rocks that are productive, for example, at Turner Valley in Alberta or the Painter 

Creek reservoir in Wyoming. 

The Brooks Range province in the NPRA is 

characterized by imbricately stacked and folded 

thrust sheets in mainly Ellesmerian rocks. Current 

interpretation suggests that these thrust sequences have been involved in very large scale tectonic transport and crustal shortening in the range 

of 250-600 km. The data suggest that vertical uplift and subhorizontal tectonic transport of Ellesmerian rocks in the western Brooks Range may be 

at least twice as great as in the Canadian Rockies 

west of Turner Valley and thus that diagenesis of 

the source and reservoir beds may be significantly 

greater. 

Because of the structural complexity and the 

disappointing history of the few wells drilled in the 

foothills and thrust-belt provinces, it is difficult to 

develop enthusiasm for their petroleum potential. 

However, the region is only lightly explored, and 

new concepts and new data could require a reevaluation in the future. The potential for deep to very 

deep reservoirs on basement-controlled structures 

of rather large areal dimensions is untested. These 

include such features as the Oumalik, Umiat, and 

Utukok platforms, where reservoir objectives 

might be present in the depth range of 2,400-

7,600 m. Although present concepts of the generation and preservation of hydrocarbons suggest 

that reservoirs may be gas prone only below 

depths of about 3,600 m and there may also be 

serious question as to the presence of adequate 

reservoir facies, these are apparently large structures that would seem to warrant serious consideration as candidates for future drilling. 

Three unique catastrophic-type structures on 

and adjacent to the Barrow arch are the Avak 

structure on the Barrow high, Simpson paleocanyon beneath Dease Inlet, and the Fish Creek paleolandslide east of the Fish Creek platform. The 

Avak structure is situated on the crest of the Barrow high. It is a semicircular feature, 13 km in 

diameter, that contains severely disrupted beds in 

the core zone and distinct listric slump faults 

around the periphery. Gravity and seismic data define a circular low within the boundary of the 

structure and a central high. The Avak well, which 

was drilled near the crest of the high, has a large 
number of core dips ranging from 40 o to 90°. Seismic data, lithology, and paleontology define severe 

bed disruption and uplift of about 100 to 500 m in 

the core. Oil shows were common, and there is no 

lithologic or petrographic evidence for hightemperature/high-pressure metamorphism. Previous reports have suggested that this structure was 

formed by meteorite impact, as a cryptovolcanic 

structure, or simply by submarine canyon erosion 

and landsliding. There are major difficulties, however, with all these interpretations. The enigma is, 

what geologic force could uplift about 11 km3 of 

semiconsolidated sediment as much as 500 m with 

no disruption of the flanking sediment that now 

contains the South and East, postdisruption, Barrow gasfields? 

The Simpson paleocanyon trends northeasterly 

across the Simpson Peninsula between Dease Inlet 

and Smith Bay. There is very good seismic, well, 

and corehole control onshore to define the canyon 

configuration on the southeast. A total of 32 shallow core tests were drilled in the vicinity of the 

East Simpson Nos. 1 and 2 wells and the Simpson 

No. 1 well. On the west beneath Dease Inlet, mudgun seismic data are poor in quality, but these 

data in combination with well control establish 

reasonable constraints on the northwesterly canyon margin. The canyon was cut in Early Cretaceous time in the Nanushuk delta-plain and Torok 

prodelta sequences. Some data indicate that the 

canyon axis may reach as deep as the top of the 

pebble-shale unit near the present coastline. The 

canyon was backfilled by shale of the Upper Cretaceous Colville Group. The core tests partly define 

the Simpson oilfield, and a few tests penetrated 

the basal canyon beds, which have a chaotic structure typical of a submarine-canyon wall. The shallow Simpson oilfield reservoirs are in Nanushuk 

sandstone, trapped by a leaky seal at the canyon 

margin. The potential for deeper, possibly economic reserves in turbidite sandstone of the lower 

part of the Torok trapped at the canyon wall has 

not yet been explored. It has also been suggested 

that reservoir sandstone beds may be present in 

the canyon axis; no data are available to confirm or 

deny this possibility. Offshore data show a complex of listric gravity faults that may have a headwall scarp near the present coastline. I conclude 

that this faulting may indicate the presence of a 

submarine landslide which localized the headward 

erosion of the canyon. 

The Fish Creek paleolandslide covers an area of 

26 

about 1,200 km2 on the east-southeast flank of the 

Fish Creek platform in the northeasternmost part 

of the NPRA. The boundary of the area is irregular 

but broadly simple; its internal structure as defined by seismic and well data is very complex and 

has not yet been mapped in detail. The disrupted 

beds involved in the slide are the Neocomian 

pebble-shale unit and the prodelta and turbidite 

beds in the lower part of the Torok Formation. An 

interpretation by Tetra-Tech, Inc., concluded that 

the seismic-diffraction pattern was universally 

symmetrical and probably due to gas-charged turbidite sand bodies. This interpretation is suspect 

because there are not only symmetrical diffractions but also one-sided bed-termination diffractions, and well data define 20°-40°-W.-dipping 

beds in the Torok Formation that are antiregional 

in comparison with the regional eastward dip. 

These west-dipping beds are confined to the 

disrupted part of the Torok Formation and occur 

in wells where the pebble-shale unit is missing. The 

pebble-shale unit is interpreted to be cut out by 

normal listric faulting, which also causes the antiregional panels of westward dip. Although some 

gas or oil accumulations may be present within the 

slide complex as interpreted by Tetra-Tech, Inc., 

the larger potential could be related to turbidite 

reservoirs of the lowermost part of the Torok 

trapped at the periphery of the slide. Similar but 

younger normal listric faulting traps the small 

Fish Creek oil accumulation. The disruption 

caused by the Simpson paleolandslide is clearly 

established as having occurred early in Torok 

time. The ages of the Simpson paleocanyon and 

the Avak structure are not so well defined but 

could be about the same as that of the Fish Creek 

paleolandslide. 

All three of these catastrophic-type structures 

are, broadly speaking, situated on the Barrow 

arch. There may be a common casual mechanism, 

possibly the disruption of gas-hydrate deposits 

during the beginning of uplift on the Barrow arch. 

In the case of the Fish Creek paleolandslide, a 

broadly simple but internally complex landslide 

resulted. In the case of the Simpson paleocanyon, 

landslum.ping triggered the rapid headward erosion of a large submarine canyon. Lastly, in the 

case of the Avak structure, the disruptive force 

must have been phenomenal, to uplift the beds of 

the Neocomian pebble-shale unit at least 500 m. 

The Jurassic sandstone reservoirs of the Barrow 

gasfields are overlapped by the pebble-shale unit 
on the northwest. This zero line probably produced 

an areally large petroleum reservoir in the early 

history of the development of the Barrow high. 

When the Avak structure breached this high, the 

accumulation was flushed into the Arctic Ocean. 

OIL AND GAS RESOURCES OF THE 

NORTH SLOPE, ALASKA 

BY KENNETH j. BIRD 

Mter 40 years of oil and gas exploration by 

Government and industry, the North Slope is now 

known to contain resources of both conventional 

and unconventional oil and gas. Conventional oil is 

currently the only economic resource, but an important one that contributes one-fifth of daily U.S. 

production. Unconventional oil resources include 

heavy oil, tar, and oil shale; unconventional gas 

resources include tight-gas sand, gas hydrates, 

coalbed methane, and geopressured methane. Our 

current understanding of these resources is based 

on two Government exploration programs, combined with information from U.S. Geological 

Survey (USGS) onshore and offshore studies, the 

literature, and industry drilling results. 

North Slope oil and gas resources occur in a region of similar geology, informally referred to herein as the North Slope petroleum province, greater 

than 260,000 km2 in area, that includes all lands 

north of the Brooks Range, an undetermined part 

of the Brooks Range, and the continental shelf and 

slope adjacent to the North Slope (fig. 5). This 

province displays a complex geologic history that 

includes marine and nonmarine sedimentation 

from the Precambrian to the Holocene interrupted 

by uwtconformities, some of which represent 

periods of orogeny. Although oil indications are 

known from pre-Mississippian metamorphic rocks, 

these rocks are generally considered nonprospective for petroleum and, therefore, economic basement. The petroleum-prospective sedimentary 

rocks in this province consist of two depositional 

sequences: an older (Mississippian to Early Cretaceous) relatively thin northern-derived sequence 

and a younger (Early Cretaceous to Quaternary) 

relatively thick southern-derived sequence. A longlasting tectonic event, which began in the Late 

FIGURE 5.-North Slope of Alaska petroleum province, showing oilfields and gasfields, major structural features, Trans-Alaska 

Pipeline (TAP), and locations of cross sections (A-A', B-B') in figure 6. 

27 
Jurassic or Early Cretaceous, initially transposed 

the sediment-source areas and later formed most 

of the structural features observed in the region today. The time of generation and the locations of 

most, if not all, North Slope petroleum accumulations are thought to have been controlled by Cretaceous and Tertiary tectonics and sedimentation. 

The northern-source assemblage of sedimentary 

rocks (Ellesmerian sequence), which averages 

about 2 km in thickness but locally may be three 

times as thick, was deposited on and partly derived from an erosionally subdued Late Devonian 

orogenic landmass (economic basement). This 

assemblage is characterized in the north by good 

to excellent reservoir rocks (including those in tile 

Prudhoe Bay field) composed of compositionally 

mature sandstone and dolomite deposited during 

several transgressions and regressions in nonmarine to shallow-marine environments along an 

east-west-trending shoreline. These rocks grade 

southward into finer grained relatively deep 

marine rocks that are potential source rocks. The 

most important petroleum-source rocks in this 

assemblage are marine shale units deposited during transgressions of the sea: the Shublik Formation, the Kingak Shale, and the pebble. shale unit 

(fig. 6). ' 

Rifting during Jurassic and Early Cretaceous 

time formed the proto-Canada basin and an uplifted basement ridge, part of which is the 

southeast-trending Barrow arch. This feature later 

became the focus of migrating hydrocarbons and 

is now the site of most North Slope oil and gas accumulations in both Ellesmerian and Brookian 

reservoir rocks. To the south, continental subduction and mountain building, possibly linked to the 

rifting event, formed the ancestral Brooks Range. 

During middle Neocomian time, renewed uplift of 

the rifted margin to the north created a regional 

erosional unconformity in northernmost Alaska 

and the offshore areas. Sandstone reservoirs 

beneath this unconformity locally show· improved 

porosity by leaching. During late Neocomian time, 

a northward transgression of the sea in response to 

subsidence of the rift margin resulted in the deposition of a thin marine shale, rich in organic material, that capped the regional unconformity and 

thus sealed several important reservoir rocks and 

terminated deposition of the northern-source 

Ellesmerian-sequence sediment. 

In the south, a rising orogenic landmass charac28 

terized by low-angle northward-directed thrust 

faulting (the ancestral Brooks Range) shed debris 

into an adjacent foredeep (the Colville trough). A 

prograding wedge of sediment, characterized by a 

distinctive shelfuslope-basin geometry, filled the 

foredeep with at least 6 km of deep-marine to nonmarine clastic sediment (Brookian sequence) and 

eventually overlapped the now-submerged Barrow 

arch. Reservoir rocks in this sequence consist of 

sandstone rich in lithic fragments, deposited in 

nonmarine to deep-marine environments. The 

reservoir quality of these rocks is generally poorer 

than that of Ellesmerian reservoir rocks. The 

petroleum source rocks consist of marine prodelta, 

slope, and basinal shale units. Basin filling, maximum sediment loading, and the deformation of 

these rocks into a series of long linear fault-cored 

detachment folds proceeded from the southwestem part of the North Slope during Albian(?) time 

to the northeastern part of the North Slope during 

late Tertiary time. Deposition of the Brookian sequence is believed to have provided the deep burial 

and subsequent heating of source rocks necessary 

for the generation of oil and gas in this province. 

Folding and faulting of reservoir rocks accompanying deposition of the Brookian sequence provided traps for migrating oil and gas. Oil and gas 

indications are known in nearly every reservoir 

rock in the province. 

To date, 21 oilfields and gasfields have been discovered on the North Slope and nearby offshore 

areas, but only two oilfields, the Prudhoe Bay and 

the Kuparuk River, are economic. These two oilfields are among the largest in the United States 

and currently produce 1.6 million barrels of oil per 

day via the Trans-Alaska Pipeline. All North Slope 

gasfields are subeconomic-including the 29 trillion ft3 of gas in the Prudhoe Bay field, representing about 14 percent of 1981 U.S. gas reserves. 

However, gas is produced from the South and 

East Barrow fields for local consumption by the 

village of Barrow. The South Barrow field, discovered in 1949, is distinguished as the earliest Arctic 

gas to be discovered and produced. 

The latest USGS estimates of petroleum resource remaining to be discovered in the entire 

onshore and offshore North Slope petroleum province (mean value of recoverable resources) are 14.4 

billion barrels of oil and 73.2 trillion ft3 of gas. The 

area of most exploratory interest is currently the 

Barrow arch, particularly its offshore extension. 
0 

0 

0 

X 

1-

w 

w 

A SOUTH & EAST 

SL WALAKPA BARROW 

5 

OIL AND GAS 

RESOURCES 

SIMPSON PRUDHOE 

A' POINT THOMSON & 

FlAXMAN ISLAND Sl 

2 

IL 10 

e Oilfield 

-3:;:t Gasfield 3 

15 

0 

0 

0 

X 

1-

w 

w 

IL 

8 

10 

20 

30 

* Oil- and Gasfield 

@ Oilshale 

@ Heavy oil I tar 

© Coalbed methane 

® Tight gas sand & geopressured methane 

...l...l..ll. Base of methane hydrate stability zone 

o· 

Slope angles~ 

-·~\"' 1" Vertical exaggeration x45 2• 

Vertical exaggeration x20 

Slope angles 

~1:· 2" 

4 

5 

8' 

4 

(/) 

a: 

w 

1-

w 

6 ~ ..1 

;;;: 

8 

10 

FIGURE 6.-Cross sections of North Slope petroleum province, showing occurrence of oil and gas resources. Thin vertical lines are 

selected· wells. Horizontal scale and resource symbols are the same for both sections. See figure 5 for locations. 

As reserves of conventional oil and gas resources 

decline and their replacement becomes more difficult, more interest is generated in unconventional oil and gas resources to meet the need for 

replacement. These resources or the requisite 

physical conditions for their existence are known 

29 

to occur in the North Slope petroleum province. 

Figure 6 shows the locations of these resources or 

the places where the requisite physical conditions 

exist. General evaluation of these resources, how.-

ever, is in only the very earliest stages. Heavy oil 

and (or) tar, which reportedly amounts to 18-40 
billion barrels in place, occurs in shallow Upper 

Cretaceous sandstone reservoirs overlying the 

Kuparuk River field; an additional 2 billion barrels 

in place is reported at the base of the oil column in 

the Prudhoe Bay field. Small amounts of heavy oil 

have been recovered from several wells in other 

areas of the Barrow arch. Oil-shale occurrences are 

limited to small isolated surface exposures in the 

foothills of the Brooks Range. These oil-shale occurrences, which apparently represent basinal condensed deposition during Mississippian, Triassic, 

and Jurassic time, are tectonically displaced and of 

limited areal extent. Tight-gas sand and geopressured methane are known in several areas of the 

Colville trough in Brookian and uppermost Ellesmerian rocks. Gas hydrates were reportedly cored 

in an industry well near Prudhoe Bay, and the 

pressure and temperature conditions necessary for 

the existence of hydrates occur over a wide onshore area generally within 50 km of the shoreline. 

Coalbed methane potential is limited to the relatively shallow occurrences in the nonmarine part 

of the Brookian sequence and the relatively deep 

occurrences in the lowermost part of the Ellesmerian sequence. Brookian coal volumes are very 

large, whereas Ellesmerian coal volumes are largely unknown. 

The role of the USGS in the exploration and 

development of North Slope oil and gas resources 

continues to be important. From the earliest general North Slope studies at the tum of the 20th 

century to the current focused studies of oil and 

gas resources, the USGS has provided the public 

with an impressive body of useful scientific data 

and interpretations pertinent to hazard identification, land classification, and resource evaluation. 

PETROLEUM SOURCE ROCK RICHNESS, 

TYPE AND MATURITY FOR FOUR ROCK UNITS 

ON THE ALASKAN NORTH SLOPE-ARE THEY 

SOURCES FOR THE TWO OIL TYPES~ 

BY LESLIE B. MAGOON AND 

GEORGE E. CLAYPOOL 

Since 1976, the U.S. Geological Survey (USGS) 

has been engaged in a comprehensive petroleum 

geochemical study to assess the petroleum 

resources on the Alaskan North Slope. This study 

involves the collection and interpretation of 

geochemical data not only from exploratory wells 

drilled in the National Petroleum Reserve in 

Alaska (NPRA) but also from wells drilled to the 

30 

east in the Prudhoe Bay area and from rocks exposed in the Arctic National Wildlife Refuge and 

in the Brooks Range from Cape Lisburne to the 

United States/Canadian border. More than 17 different kinds of rock analyses, eight different oil 

analyses, and three gas analyses are being used to 

evaluate rock (outcrop samples, core, drill cuttings), oil (seeps, drill stem test, oil-stained core, 

producing well), and gas (drill stem test, producing 

well) samples on the North Slope. To date, the 

more than 60,000 analyses completed on these 

samples have been placed into a computer-based 

file for storage and retrieval in tabular, graphical, 

or map form; numerous graphical software programs have been written to facilitate interpretation and publication. So far, these petroleum 

geochemical data have been used to map and 

evaluate the organic matter content, type, and 

thermal maturity of the major rock units and to 

characterize the known oil and gas occurrences. 

This evaluation of petroleum source rock 

richness, type, and thermal maturity on the 

Alaskan North Slope is based on five petroleum 

geochemical analyses (organic carbon content, c15+ 

hydrocarbon content, elemental analysis, visual 

kerogen, and vitrinite reflectance) that were 

routinely performed on rock samples from 63 

Government-drilled wells within or adjacent to the 

NPRA. Samples were selected from rocks ranging 

widely in depth and age: from surface to 20,000 ft 

and from Tertiary to Ordovician. Sample material 

includes drill cuttings, sidewall cores, and conventional cores. Contour maps to evaluate the petroleum source rock richness, type, and thermal 

maturity were drawn for 12 of the stratigraphic 

units penetrated. 

Organic carbon content (wt %), c15+ hydrocarbon 

content (ppm), elemental analysis, and visual kerogen type indicate that the Shublik Formation (Triassic), the Kingak Shale (Jurassic), the pebble shale 

unit, and the Torok Formation (both Cretaceous) 

are petroleum source rocks. Even though rock units 

younger than the Nanushuk Group (Cretaceous) 

have organic carbon contents higher than 1 wt %, 

they are so immature that they can be considered 

only potential source rocks. The Nanushuk Group 

and the Sag River Formation (Triassic) include 

shale that, in most places, resembles the source 

shale within the Torok Formation and the Shublik 

Formation/Kingak Shale, respectively. The Endicott (Devonian and Mississippian), Lisburne 

(Mississippian and Pennsylvanian), and Sadlerochit 
(Permian and Triassic) Groups, though not source 

rocks, contain migrated hydrocarbons. 

Thermal maturity, measured by vitrinite reflectance (% Rc,), increases from north (the Barrow 

high) to south (the Colville trough). Within the Colville trough, for a given stratigraphic depth, the 

western part of the NPRA region has a higher reflectance value than the eastern part. Within the 

NPRA, well control is sufficient to indicate that 

the Upper Cretaceous and Tertiary rocks are in the 

diagenetic stage (~0.6% Ro) of petroleum generation. Substantial volumes of the Jurassic and 

Lower Cretaceous rocks have reached the liquid 

window or catagenic stage (0.6-2.0% R0), whereas 

most of the pre-Jurassic rocks are in the metagenetic stage (¥22.0% R0) of petroleum generation. 

A total of 40 oil samples from across the North 

Slope have been analyzed by the U.S. Bureau of 

Mines and the U.S. Geological Survey. Results of 

these analyses suggest two distinct genetic oil 

types. The first, the Simpson-Umiat oil type, occurs in reservoir rocks of Cretaceous and Quaternary age and includes oil from seeps in the Skull 

Cliff, Cape Simpson, Manning Point, and Ungoon 

Point areas, and oils from WoH Creek test well no. 

3 and the Cape Simpson and Umiat oil fields. 

These are higher gravity, low-sulfur oils with no, 

or only slight, odd-numbered n-alkane predominance and pristane-to-phytane ratios greater than 

1.5. Also, these oils have 1

ac values ranging from 

-29.1 to -27.8 permil and 34Svalues ranging from 

-10.3 to -4.9 permil. 

The second type, the Barrow-Prudhoe oil type, 

occurs in reservoir rocks of Carboniferous to 

Cretaceous age and includes oils from South Barrow gas field, Prudhoe Bay oil field, and Fish 

Creek test well no. 1. Physical properties of the 

Barrow-Prudhoe oil vary, but generally the oil is a 

medium-gravity high-sulfur oil with slight evennumbered n-alkane predominance and pristane-tophytane ratios less than 1.5. This oil has 1

ac values 

of -30.3 to -29.8 permil and 34S values of from 

-3.0 to +2.1 permil. 

The next phase of this work is to determine 

which rock unit may have generated a particular 

oil type. Toward this goal, a unique 2-year study 

has been carried out by 30 research groups from 

Government, industry, and academia, representing the United States and seven other countries, to 

analyze the same 15 rocks and nine oils from the 

North Slope. This study, conceived and organized 

by the USGS and sponsored by the American 

31 

Association of Petroleum Geologists (AAPG), included a 4-day research conference in 1983, a 1-day 

short course at the AAPG 1983 Annual Meeting 

in Dallas, and a symposium volume that will be 

published in 1984. There were three objectives: (1) 

to provide similar data on the same samples from 

various research groups for interlaboratory comparison; (2) to compare various analytical techniques used by different research groups in evaluating petroleum source rocks and oils; and (3) to 

determine which shale units penetrated in the 

NPRA could have been sources for North Slope 

oils. Research methods, results, and interpretations varied widely. One method that was commonly used was a conventional one-gas chromatography. In addition, other groups applied the 

more advanced technology of computerized gas 

chromatography/mass spectrometry (GC-MS), 

which enabled the researchers to examine both 

saturated and aromatic hydrocarbons in greater 

detail; carbon isotope, fluorescence, and pyrolysis 

were other methods employed. Results from a few 

groups indicated no correlation between any of the 

shale units and oils. However, the consensus was 

that the Shublik Formation and the Kingak Shale 

correlate with the Barrow-Prudhoe oil type and the 

pebble shale unit and, possibly, the Torok Formation are the source for the Simpson-Umiat oil type. 

Future work for our group will include (1) further 

investigation into oil-rock correlation to refine our 

understanding of the origin of North Slope oil and 

(2) interpretation of the large number of petroleum 

geochemical data on samples acquired in the 

Brooks Range thrust belt. Results of investigations should provide clues to the oil and gas potential of the thrust belt and reveal how this belt 

relates to the oil accumulations in the north. 

EMERGING RECOGNITION OF THE NONFUEL 

MINERAL RESOURCES OF ARCTIC ALASKA 

BY DONALD GRYBECK 

Some of the most exciting new mineral discoveries in Alaska during the past two decades have 

been in the Brooks Range, yet conventional 

wisdom 25 years ago was that northern Alaska 

was rather unpromising, if not geologically unfavorable for mineral deposits. Nonetheless, what has 

emerged in the Brooks Range is a mineral frontier, 

largely as a result of detailed geologic mapping, 

systematic mineral exploration, better accessibility, and new ore-deposit models. 
In 1898, a wave of prospectors began moving 

through northern Alaska in their quest for gold, 

and by 1909 they had discovered all the gold placer 

districts that are known today-Chandalar, Koyukukk, and Kiana-as well as several lode prospects. Also in 1898, the U.S. Geological Survey 

(USGS) began its geologic exploration of northern 

Alaska and by the early 1940's had mounted several expeditions that defined the basic geographic 

and geologic framework of northern Alaska. In 

1944, the USGS began extensive geologic studies 

of Naval Petroleum Reserve Number 4, and by 

1953 had a good understanding of the geology of 

the Arctic Coastal Plain and the Arctic foothills. 

But by 1950, in spite of more than a half-century of 

work, the geologic map of the Brooks Range still 

had large blank areas, most of the range remained 

essentially inaccessible, and relatively little 

mineral exploration had been done. In the early 

1950's, helicopters were first used for geologic 

mapping in the Brooks Range. Although their introduction produced no immediate breakthroughs, 

in retrospect it was pivotal. Systematic geologic 

mapping and mineral exploration became practical 

for the first time and has continued unabated 

since. 

In 1957, Bear Creek Mining Co. began exploration of the bornite copper deposit in the Ambler 

district and soon after began mineral exploration 

throughout the Brooks Range. Their first worldclass discovery was the Arctic copper-zinc massive 

sulfide deposit in 1965. Further work by several 

companies has now detailed a belt of copper-zinc 

massive sulfide deposits more than 160 km long 

along the south flank of the Brooks Range. Similarly, the initial discovery of zinc-lead mineralization in the De Long Mountains by I.L. Tailleur 

of the USGS in 1969 has led to delineation of the 

Red Dog deposit, a large volocanogenic massive 

sulfide deposit now being developed by Cominco 

Ltd., as well as several smaller similar deposits, 

and to recognition of widespread potential for 

other volcanogenic deposits along the northwest 

flank of the Brooks Range. Though not so noteworthy, numerous other deposits of various types 

have been found in the past 20 years, including 

several porphyry copper deposits, one porphyry 

molybdenum deposit, several barite deposits, and 

many others. 

In view of the naivete of past projections, it may 

be premature to suggest how many mineral deposits yet lie undiscovered in northern Alaska, or 

32 

their locations. However, even if some of the larger 

deposits have already been found, large areas have 

yet to be examined in any but cursory fashion and 

the expanding geologic data base and catalog of 

identified types of deposits strongly suggest that 

many other large deposits do exist in the Brooks 

Range. 

COAL OCCURRENCE, QUALITY, 

AND RESOURCE ASSESSMENT, 

NATIONAL PETROLEUM RESERVE IN ALASKA 

BY GARY D. STRICKER 

Field studies by U.S. Geological Survey personnel in 1977 and 1978 of the Cretaceous Torok, 

Kukpowruk, and Corwin Formations in the westem portion of the NPRA (National Petroleum Reserve in Alaska) and Cretaceous Torok, Tuktu, 

Grandstand, and Chandler Formations in the eastem portion of NPRA indicate that two major delta 

systems are responsible for most of the coal 

accumulation in this area. The Corwin delta in the 

western portion of NPRA was an early Albian to 

Cenomanian, north and east prograding system, 

whereas the slightly younger mid-Albian to Cenomanian Umiat delta system prograded north and 

northeast in the eastern portion of NPRA. Investigations of the lithologies, fossils, and primary 

depositional structures of these formations indicate that the Corwin system was deposited as a 

large, high-constructional, ''birdfoot'' shaped delta 

on which thick (as much as 10m) and numerous 

coals developed on splay and interdistributary bay 

platforms away from the influence of the Cretaceous epicontinental sea. The Umiat delta started 

out as a high-constructional system but in time 

became wave dominated, and its shape changed to 

lobate. Boreholes indicate that north of the outcrop belt, the rocks of the Umiat delta quickly lose 

their non-marine characteristics. Because of the 

small size of the Umiat delta and marine influences 

on it, coals were laid down in sparse, thin, and 

discontinuous beds. 

Eighty-six coal samples have been collected 

from NPRA as part of a comprehensive program 

by the U.S. Geological Survey to describe the 

chemistry of United States coal. These samples 

consist of face channel, grab, auger, and drill core 

samples. Proximate and ultimate analyses, heatof-combustion, air-dried loss, and forms-of-sulfur 

determinations were run on 36 samples; major and 
minor oxides and trace element analyses were performed on all 86 samples to determine coal quality. 

An additional 20 proximate and ultimate analyses 

were determined by the U.S. Bureau of Mines. In a 

total of 106 samples, 10 samples are from the 

eastern portion, 9 samples from the central portion, and the remaining 87 are from the western 

portion of NPRA. 

Apparent coal rank ranges from lignite A to 

high volatile A bituminous coal, with the highest 

ranked coals located in the southern half of NPRA. 

Sulfur content ranges from 0.10 percent to 2.0 percent, which appears comparable to that of other 

Western United States coals of similar rank. The 

concentrations of trace elements of environmental 

concern such as As, Be, Hg, Mo, Sb, and Se also 

appear similar to major Western United States 

coals. 

Published estimates of unidentified coal resources in NPRA range from just over 100 billion 

to 3.3 trillion short tons. Based on published data, 

there are approximately 50 billion short tons of 

identified coal resources in NPRA. For an area as 

large as NPRA, available data are insufficient to 

indicate any realistic potential coal resources. 

PERMAFROST AND THE GEOTHERMAL REGIME 

BY ARTHUR H. LACHENBRUCH AND 

B. V. MARSHALL 

Permafrost is the region in the solid earth where 

the temperature is below ooc summer and winter. 

Within this region, water usually occurs as ice, 

often in massive segregated forms, although capillary water, brines, and gas hydrates also occur. 

The frozen condition renders permafrost impermeable to water flow, subject to brittle fracture under 

seasonally induced thermal stress, and subject to 

mechanical failure and flow when thawed by 

natural processes or disturbed by man. Hence an 

understanding of the factors controlling the geothermal regime is necessary for an understanding 

of geomorphic processes and for successful design 

of engineering structures such as roadways, 

heated buildings, pipelines, and oil wells in permafrost terrains. Studies of these factors are greatly 

simplified by the general absence of heat transfer 

by flowing ground water; temperatures can be 

estimated with confidence from heat-conduction 

theory if the ground surface temperature, regional 

heat flow, and thermal properties are known. 

The equilibrium thickness of permafrost varies 

33 

inversely with regional heat flow and directly with 

thermal conductivity, and the subzero value of 

mean surface temperature. Thus the heat flow and 

surface temperature are similar at Barrow and 

Prudhoe Bay, but permafrost is twice as thick at 

Prudhoe Bay (620 m) because the thermal conductivity of the ice-rich siliceous sediments there is 

twice as great. The primary cause of variable permafrost thickness at NPRA (200-400 m) is probably local variation in thermal conductivity. 

However, work in progress by our colleagues, John 

Sass and Robert Munroe, suggests that there 

might also be important lateral variations in heat 

flow, possibly associated with migration of fluids 

deep in the sedimentary basin. 

The periodic variation in surface temperature 

from summer to winter determines the position of 

the top of permafrost, as it generates the active 

(seasonally thawed) layer upon which man's activities take place. The thickness of the active 

layer is very sensitive to its thermal properties and 

to the mean and annual range of surface temperature. Modification of the surface, whether by 

natural processes or by man, generally changes all 

three parameters and the thickness of the active 

layer as well. Seasonal temperature variations also 

cause visco-elastic thermal stress in permafrost 

which results in networks of recurring tension 

cracks, meters deep and tens of meters apart. 

Seasonal freezing of meltwater in the cracks 

results in the growth of networks of massive ice 

wedges; differential settlement of the tundra surface above these wedges under changing active 

layer conditions, controls surface drainage patterns and is a principal cause of damage to engineering structures. 

Recent systematic changes in the mean annual 

surface temperature leave tell-tale curvature in the 

geothermal profile from which the surface change 

can be investigated by conduction theory. Observations in wells along the Alaskan Arctic Coast indicate a surface warming of 1 Y2 to 3 o C in the last 

100 years or so with a net accumulation of heat by 

the solid earth surface of 5-10 Kcal/cm2 during the 

event. 

Surface bodies of water such as lakes, rivers, and 

shallow seas that do not freeze to the bottom 

represent hot spots on the surface in permafrost 

terrain. In northern Alaska, such bodies deeper 

than 2 m have mean bottom temperatures close to 

0°C, about 10°C warmer than the emergent surface beyond their shores. The configuration of 
these bodies continually changes as lakes are 

drained or shorelines migrate as a result of thermal 

erosion. Two- and three-dimensional transient 

conduction models permit a calculation of the 

configuration of the underlying thawed region for 

application to water-supply problems, or a reconstruction of the shoreline history from the lingering thermal effects at depth. According to a recent 

synthesis by David Hopkins, rising sea level and 

thawing ice-rich sea cliffs probably caused the 

shoreline of the Beaufort Sea to retreat tens of 

kilometers in the last 20,000 years inundating a 

part of the Alaskan continental sheH that is 

presently the target of intensive oil exploration. A 

simple transient conduction model applied to the 

Prudhoe Bay area suggests that this recently inundated region is underlain by near-melting, icerich permafrost to depths of 300-500 m; its presence is important to seismic interpretations in oil 

exploration and to engineering considerations in 

oil production. When permafrost configurations 

are confirmed by offshore drilling, heat-conduction 

models should yield reliable new information on 

the chronology of arctic shorelines. 

GLACIATION IN ARCTIC ALASKA 

BY THOMAS D. HAMILTON 

The glacial record of arctic Alaska includes advances of late Tertiary age, a complex sequence of 

Pleistocene fluctuations, and minor expansions of 

cirque glaciers during the Holocene. Glaciers 

originated mainly within the Brooks Range, a 

150-km-wide mountain chain that extends across 

northern Alaska The range evidently supported 

extensive ice caps during late Tertiary and early 

Pleistocene glaciations, because erratics of Brooks 

Range provenance indicate that large ice streams 

and piedmont glaciers fed from alpine sources extended far to the north across the Arctic Slope. 

Glaciers of middle and late Pleistocene age were 

successively less extensive; they were mainly confined to mountain valleys and flowed only short 

distances beyond the north flank of the range .. A 

second ice source, probably in the Canadian Arctic, was responsible for ice-rafted erratics in late 

Cenozoic marine deposits along the Arctic coast 

east of Barrow. A third ice source may be indicated by erratics of unknown provenance in Tertiary(?) gravel near the Colville River delta Only 

the record produced by Brooks Range glaciers will 

be considered here (fig. 7). 

34 

Pre-Pleistocene(?) GU1ciation. The oldest glacial 

interval in the Brooks Range is represented by the 

informally named "Gunsight Mountain" erraticsisolated boulders of highly resistant rock types 

beyond the limits of recognizable drift of Pleistocene age. These erratics typically occur on uplifted 

plateaus along the north flank of the Brooks 

Range; they cannot be traced to existing mountain 

valleys. The extent of erratics north of the range 

suggests that much of the precipitation that nourished the glaciers may have been derived from the 

north, probably prior to formation of the present 

sea-ice cover over the Arctic Basin. 

Early(?) Pleistocene GU1ciation. The oldest 

recognizable drift sheet in the Brooks Range is 

assigned to the Anaktuvuk River Glaciation. 

Glaciers of Anaktuvuk River age flowed through 

mountain valleys at levels generally 100 m or more 

above their modem floors. Extenstve moraines 

beyond the mountains are fairly continuous but 

subdued, with low slope angles, mature drainage 

networks, complex thaw-lake basins, and sparse 

erratics. The drift sheets have been dissected by 

streams that flowed 40-65 m above modem levels 

and eroded valleys as wide as 10 km within the 

glacial deposits. 

Middle Pleistocene GU1ciation. The complex of 

drift sheets assigned to the Sagavanirktok River 

Glaciation was deposited after a long interval of 

valley enlargement and pedimentation that followed Anaktuvuk River time. Drift extends into 

valley centers, where it generally stands within 

40 m of modem stream levels. Moraines retain 

much of their original morphology, but deposits 

are deeply oxidized, subdued by mass wastage, 

and dissected by streams. Two separate drift 

sheets assigned to the Sagavanirktok River Glaciation are present locally. 

Late Pleistocene GU1ciation. Glacial deposits of 

late Pleistocene age occupy modem valley floors 

and generally are little eroded; their stony surfaces 

lack deep weathering. The drift sheets are divisible 

into older and younger complexes, assigned respectively to the Itkillik and Walker Lake Glaciations of early and late Wisconsin age. Itkillik 

deposits are slightly oxidized, and are somewhat 

subdued by postglacial solifluction and patternedground formation. Walker Lake deposits, dated by 

radiocarbon at between 24,000 and 11,500 yr B.P., 

are morphologically fresh, have little solifluction 

cover, and still are partly ice cored. 

Holocene GU1ciation. An interval of milder 
HOLOCENE ~ Drift of Fan Mountain Glaciation 

LATE WISCONSIN 

Drift of Walker Lake Glaciation 

EARLY WISCONSIN Drift of Itkillik Glaciation 

"Bettles Gravel" 

Drift (upper) of Sagavanirktok River Glaciation 

MIDDLE PLEISTOCENE 

Drift (lower) of Sagavanirktok River Glaciation 

Deep incision of mountain valleys 

EARLY(?) PLEISTOCENE 

Drift of Anaktuvuk River Glaciation 

Deep incision of mountain valleys 

PRE-PLEISTOCENE 

"Gunsight Mountain" 

erratics 

Figure 7.-Tim&distance diagram, showing late Cenozoic events and glacial deposits of the north-central Brooks Range, Alaska. 

Horizontal axis (not to scale) shows distance north of modem valley heads along Continental Divide. 

35 
climate in northern Alaska was followed by ice advances and alluviation of mountain streams beginning around 4,500 to 3,000 yr B.P. Drift formed by 

expanded cirque glaciers in the Brooks Range is 

assigned to the Fan Mountain Glaciation, which 

occurred in two phases separated by a milder interval between about 2,000 and 1,000 years ago. 

A PLEISTOCENE SAND DESERT IN ARCTIC 

ALASKA 

BY L. DAVID CARTER 

A sand desert composed of large dunes and barren sand plains extended across a significant part 

of Arctic Alaska north of the Brooks Range during 

late Pleistocene time. The dunes occupied about 

11,600 km2 of the Arctic Coastal Plain west of the 

Colville River, and the sand plains extended at 

least 100 km northeast of the dunes. This sand 

desert was part of an eolian system that extended 

about 400 km from sediment sources on outwash 

plains and fans in the east to where waning winds 

deposited loess along the margin of the Arctic 

Foothills southwest of the dunes. 

Linear dunes, as much as 20 km long and 1 km 

wide (Carter, 1981), make up the eastern 7,000 km2 

of the dune field, but dune types in the rest of the 

area have not yet been classified. All the Pleistocene dunes are obscured by a thin cover of younger 

eolian sand that includes small stabilized longitudinal and parabolic dunes, identified during earlier 

U.S. Geological Survey fieldwork (Black, 1951). In 

addition, the Pleistocene dunes have been extensively modified by thermokarst processes. 

Radiocarbon ages of herbaceous plants from 

eolian and lacustrine sand within the dune field indicate that the dunes were active from before 

36,000 to nearly 12,000 yr B.P. Bedding attitudes, 

dune-ridge orientations, and measurements of 

pseudocrosslamination formed by climbing adlhesion ripples demonstrate a wide regime similar to 

that of the present and indicate that the dominant 

directions of sand-moving winds were easterly to 

northeasterly. ' 

Former barren-ground and dry-surface conditions upwind of the dunes are indicated by fossil 

sand wedges, as much as 7 m deep and 3 m wide 

(Carter, in press). Observations of modem sand 

36 

wedges in Antarctica indicate that these wedges 

develop beneath vegetation-free surfaces in the 

most arid regions by the repeated formation of 

thermal-contraction cracks and subsequent filling 

with loose sand. The Alaskan fossil sand wedges 

are composed of sand that is texturally· distinct 

from the host materials but similar to the sand 

composing the dunes. The loose sand that filled 

the thermal-contraction cracks evidently was 

derived from wind-driven sand moving across the 

coastal plain toward the dunes. 

The linear dunes and sand wedges thus define a 

zone of mobile sand that was dry, barren, and 

windswept during middle and late Wisconsinan 

time and, possibly, throughout the Wisconsinan. 

During this same period, however, large lakes 

formed south of this zone where drainage from the 

Arctic Foothills was blocked by the dunes; and in 

the loess terrane south and west of the lakes, surface moisture was sufficient to create syngenetic 

ice wedges. Extensive tracts of barren ground may 

have been limited to the zone of mobile sand during much of this period because radiocarbon 

dating of fossil bones indicates that before 28,000 

years B.P. vegetation in the loess terrane was sufficient to support such large herbivores as mammoth, horse, and bison (Carter, 1982). However, 

none of the dates on these mammals is less than 

28,000 years B.P., and few organic remains have 

been found in coastal-plain deposits between 

14,500 and 28,000 years old relative to both older 

and younger deposits. Desert conditions may have 

expanded beyond the zone of mobile sand during 

the late Wisconsinan cold phase to include most of 

the Arctic Coastal Plain and the Arctic Foothills. 

Steppe-tundra vegetation and large mammals may 

not have persisted into late Wisconsinan time 

throughout this vast region. 

REFERENCES CITED 

Black, R. F., 1951, Eolian deposits of Alaska: Arctic, v. 4, 

Po 89-111. 

Carter, L. D., 1981, A Pleistocene sand sea on the Alaskan 

Arctic Coastal Plain: Science, v. 211, p. 381-383. 

Carter, L. D., 1982, Laoo Wisconsin desertification in northern 

Alaska: Geological Society of America Abstracts with Pro-

~.v.14,no.7,p.461. 

Carter, L. D., in press, Fossil sand wedges on the Alaska Arctic 

Coastal Plain and their paleoenvironmental significance, in 

Proceedings of the Fourth Inoomational Conference on 

Permafrost: Washington, National Academy Press. 
SEDIMENTARY FACIES ON AN 

ICE DOMINATED SHELF, BEAUFORT SEA, 

ALASKA 

BY PETER W. BARNES AND ERK REIMNITZ 

Sea ice is a major factor influencing the character of high latitude shelf deposits today and has 

been throughout the Quaternary. Ice impacts sedimentation by physically disrupting the sea floor, 

by influencing wave and current regimes, by rafting sediments to depocenters and by affecting the 

erodability of seabed materials. As a result of this 

interaction distinctive facies are developed in the 

surficial sediments. 

The ice environments affecting the shelf stratigraphy can be divided into three zones. Inshore of 

about 20 m is the semistationary fast-ice, which is 

inundated with flood waters near rivers in the 

spring. Between about 20 m and 40 m a zone of 

grounded ice ridges composed of seasonal and multiyear ice (called stamukhi) is present during the 

winter and often lasts into the summer months. 

Seaward of the stamukhi zone, polar pack ice is in 

motion through much of the year, its depth of penetration onto the shelf is controlled by seasonal 

weather pattern and ice draft. 

The ice zonation has resulted in a characteristic 

sedimentary facies in the different ice environments as follows: 

1) Delta facies-The normal interplay of sediment 

supply and marine reworking is seasonally interrupted by ice flooding and vertical drainage through the ice canopy (strudel) creating 

scour depressions whose fill becomes the 

dominant delta facies. Bedding is laterally 

discontinuous due to repeated strudel scouring. The stratigraphy is characterized by 

alternating layers of sand and finer materials 

and layers of fibrous organic matter. Gravel is 

notably absent in the marine part of modem 

delta facies. 

2) Fast ice zone facies-Although ice gouging in 

this zone occurs at a rate high enough to completely rework the surficial sediments in less 

than. 200 years, hydraulic processes are 

resp6nsible for the sedimentary structures observed in this zone. These processes infill 

gouges with finely laminated sands and mud 

while unbedded sandy mud is derived from 

the gouging and mixing processes. The resulting facies is a bedded sequence of sand and 

37 

finer material with finer grained beds often 

contorted, mottled and structureless. Laterally discontinuous beds are composed of ice 

gouge infill which results in linear "shoestring" deposits characterizing this part of 

the shelf. 

3) Stamukhi zone facies-Ice gouging becomes the 

dominant agent in forming sedimentary 

structures plowing and replowing the seafloor 

mixing the sediments into a heterogeneous 

mass. The resulting facies in this zone grades 

seaward from the fast ice zone facies· through 

a zone of contorted bedded sequences to completely heterogeneous sequences of gravelly 

muds in waters 30 to 40 m deep. 

4) Outer shelf facies-In waters deeper than 50 m, 

few ice ridges grow large enough to interact 

with the seafloor and hydraulic processes 

dominate sedimentary structures. The resulting outer shelf facies is characterized by 

bedded sequences of muds and sandy muds 

which are laterally continuous. 

During the transgressions and regressions of the 

Quaternary these facies extended to deeper water 

on the arctic shelves and would have been a part of 

the facies on subarctic shelves where sea ice was 

present. These facies would also be present in 

glacial lakes where lake ice formed and interacted 

with the lake beds. 

QUATERNARY SEDIMENTATION ON THE 

ALASKAN BEAUFORT SHELF: SEDIMENT 

SOURCES, 

GLACIOEUSTATISM, AND REGIONAL TECTONICS 

BY DAVID A. DINTER 

Shallow sedimentary strata underlying the middle and outer continental shelf of the Alaskan 

Beaufort Sea compose, in general, a sequence of 

wedges, each of which thickens seaward to the 

shelf break. At least seven such wedges, with maximum seaward thicknesses on the order of 15 to 40 

meters, are recognized on high-resolution seismic 

reflection profiles. The wedges are bounded by 

disconformities that presumably represent successive subaerial exposures of the shelf during 

Quaternary glacioeustatic sealevel minima. Many 

of these surfaces are intermittently channelled 

beneath the middle shelf, and some are overlain by 

thin, discontinuous, acoustically chaotic layers inferred to be nonmarine or shallow marine in origin. 
Seaward of several river mouths foreset sequences 

less than 15 meters thick are intercalated between 

some of the wedges. 

Several of the wedge-shaped strata die out inshore beneath the middle shelf. At least three, 

however, persist in thicknesses of 2 to 10 meters at 

the shoreward ends of seismic profiles, which typically lie close to the 25-meter isobath some 20 to 

30 kilometers from shore. Tentative correlations 

with shallow boreholes seaward of the barrier 

islands (Peggy Smith and David Hopkins, personal commun., 1983) support the interpretation 

that these strata are primarily marine, and accumulated in late Quaternary time during relative 

highstands of the sea. 

Lithologies of surficial gravel samples from 

seabottom exposures of the top of the youngest 

wedge are exotic to Alaska, but similar to Paleozoic suites exposed on the shores of Coronation 

Gulf in the Canadian Arctic Islands. Rodeick 

(1979) has proposed this area as the probable 

source of the gravels and suggested ice-rafting as 

the most feasible transport mechanism. A great 

volume of sediment-laden icebergs must have been 

shed from the Canadian Arctic Islands into the 

Arctic Ocean during the decay of the Laurentide 

Ice Sheet in late Wisconsin/early Holocene time. 

This period coincides with the early phases of the 

reinundation of the shelf subsequent to the latest 

glacioeustatic sea level minimum approximately 

18,000 years ago and so appears to be a likely time 

of deposition for the now-relict gravels on the 

shelf. It is possible that earlier Canadian Arctic ice 

sheets were significant sediment sources for the 

older Quaternary wedges underlying the Alaskan 

Beaufort shelf. 

An exception to the idealized shallow stratigraphic geometry discussed above occurs on the 

eastern part of the Alaskan Beaufort shelf, where a 

persistent structural high some 30 km wide and 

60 km long trends northeast from Camden Bay. 

The youngest sedimentary wedges on the shelf onlap the. flanks of this arch, and nearly every earthquake recorded from the shelf has an epicenter in 

the area marked by a paucity of late Quaternary 

sediment (Grantz and Dinter, 1980; Dinter, 1982). 

Near the axis of the arch strongly deformed strata 

of unknown age are exposed within 1 meter of the 

seafloor. 

Seaward of the shelf break, slides and slumps 

pervasively disrupt the shallow sedimentary 

strata such that stratigraphic horizons prominent 

38 

over great distances beneath the shelf cannot be 

traced further downslope on reflection seismic 

profiles. 

REFERENCES CITED 

Dinter, David A, 1982, Holocene marine sediments on the middle and outer continental shelf of the Beaufort Sea north of 

Alaska: U.S. Geological Survey Map 1-1182-B, with text, 

5 p., 1 fig., 2 map sheets. 

Grantz, Arthur, and Dinter, David A, 1980, Constraints of 

geologic processes on petroleum development in the Westem Beaufort Sea: Oil and Gas Journal, v. 78, no. 18, 

p. 304-319. 

Rodeick, C. A, 1979, The origin, distribution, and depositional 

history of gravel deposits on the Beaufort Sea continental 

shelf, Alaska: U.S. Geological Survey Open-File Report 

79-234, 87 p., 31 figs. 

PERMAFROST AND RELATED ENGINEERING 

PROBLEMS ON THE NORTH SLOPE AND 

BEAUFORT SHELF, ALASKA 

BY OSCAR J. FERRIANS, JR. 

The critical need for finding and developing new 

and dependable sources of hydrocarbon resources 

has caused a tremendous increase in exploration 

and development activities on the North Slope of 

Alaska and on the shelf of the Beaufort Sea. These 

regions pose special engineering problems and are 

environmentally ''sensitive.'' Consequently, they 

require careful study and consideration to ensure 

the integrity of engineering structures and to 

minimize adverse environmental impacts. One of 

the most important factors to be considered in 

these northern regions is permafrost. 

Permafrost, or perennially frozen ground, is a 

widespread natural phenomenon. It underlies approximately 20 percent of the land area of the 

world, and 85 percent of Alaska is within the permafrost region. In Alaska, the known permafrost 

thickness ranges from about 600 m near Prudhoe 

Bay to less than a meter at the southern border of 

the permafrost region. On the North Slope, permafrost thickness generally is greater than 200 m. 

Locally, however, it is absent under large lakes 

deep enough so that they do not freeze to their bottoms in the winter. 

The distribution and character of subsea permafrost is still poorly understood; however, icebonded permafrost is known to be widespread 

under the shelf of the Beaufort Sea. This subsea 

permafrost generally differs from the adjacent onshore permafrost by being warmer and containing 
less ice. Most of the subsea permafrost is relict, 

having formed under subaerial conditions at a 

time when sea level was much lower than it is 

today. 

Thawing of ice-rich permafrost, the most serious 

permafrost-related engineering problem, results in 

a loss of strength and a change in volume of the 

ice-rich soil. Under severe conditions, the ice-rich 

soil can liquefy and lose essentially all of its 

strength. A more common occurrence is differential settlement of the ground surface. 

Proposals to chill the natural gas in buried pipelines as a means of mitigating the problems caused 

by the thawing of permafrost pose different 

problems-the most difficult to solve is frost heaving caused by the freezing of unfrozen soils surrounding the pipe. 

The two basic methods of constructing on permafrost are (1) the active method and (2) the passive method. The active method is used in areas 

where permafrost is thin and generally discontinuous, or where it contains relatively small amounts 

of ice. The object of this method is to thaw the 

permafrost and, if the thawed material has a satisfactory bearing strength, then to proceed with construction in a normal manner. 

The object of the passive method is to keep the 

permafrost frozen so that it will provide a firm foundation for engineering structures. Obviously, the 

passive method has wide application on the North 

Slope where permafrost is widespread, thick, and 

generally ice rich near the surface. When using this 

method, every effort should be made to minimize 

disturbing the ground surface, and when the 

ground surface is disturbed, to take carefully 

planned mitigative measures immediately. Various 

techniques used to help keep the permafrost frozen 

include using different kinds of insulation (both 

natural and man-made), elevating heated structures 

abOve ground, and using refrigeration. 

QUATERNARY MICROFOSSILS ON THE 

ARCTIC SHELF 

BY KRISTIN McDOUGALL 

Late Pliocene and Quaternary marine transgressions on the Arctic Coastal Plain are each defined 

by a particular sea level stand and by temperature 

changes relative to the present conditions. Microfossils are common and generally well preserved in 

the marine strata. Foraminifers which are sensi39 

tive to depth, temperature, salinity or oxygen, can 

be used to identify the transgressive-regressive 

cycles through faunal changes which correspond 

to the environmental changes. 

Benthic foraminifers have been identified in a 

series of offshore boreholes along the Arctic 

Coastal Plain. Transgressions represented in these 

boreholes range from Berringian to Holocene in 

age. Foraminiferal faunas in the oldest transgressions (Berringian to Fishcreekian) are poorly 

represented as material of this age is rarely 

encountered. The younger transgressions (Kotzebuan through Holocene) are well represented, and 

microfossils associated with these transgressions 

can be described and traced throughout the Arctic 

Coastal Plain. 

Kotzebuan and Pelukian faunas are characterized by moderate foraminiferal numbers, moderate 

diversities, indigenous Pacific and Atlantic 

species, warmer temperatures and deeper waters. 

Kotzebuan faunas generally indicate greater water 

depths and a greater Pacific and Atlantic influence 

than during the Pelukian. 

Kotzebuan assemblages are recognized only in 

boreholes seaward of the barrier island chain from 

Flaxman Island to Prudhoe Bay. Although the 

strata are of variable thickness, Pelukian assemblages are present in most boreholes on the Arctic 

Coastal Plain between Flaxman Island and the 

Jones Islands. Both Kotzebuan and Pelukian 

assemblages contain common occurrences of 

Cassidulina teretis, C. norcross~ C. islandica, 

Elphidium orbiculare, E. incertum, and Buccella 

frigida. Outer neritic and deeper water species 

such as Stainforthia concava are sparse, whereas 

elphidiums and other inner neritic species are more 

common in the Pelukian than in the Kotzebuan, 

reflecting the higher stand of sea level in the 

Kotzebuan. Elphidiella groenlandica, Elphidium 

asklu~ Eggerella advena, and Gordiospira arctica are present as a result of the warmer 

temperatures and the influx of Atlantic and 

Pacific waters. 

Faunas of the early Wisconsin, Flaxman transgression, have moderate foraminiferal numbers, 

lower diversities, and indicate that water depths 

and temperatures were shallower and cooler than 

during the Pelukian or Kotzebuan transgressions, 

but deeper and warmer than at present. Cassidulinids decrease significantly in abundance and constitute only a minor component of the Flaxman 

faunas. Elphidiella groenlandica, Elphidium 
asklundi, and Elphidium excavatum alba also 

become increasingly rare as the temperatures cool. 

The Flandarian transgression is marked by low 

foraminiferal numbers, low diversities and cold 

shallow waters which were less saline than at present. Elphidium clavatum is the dominant species 

in most Flandarian faunas. 

Holocene faunas are best preserved and most 

variable. In general, the foraminiferal numbers are 

high and species diversities are moderate to low. 

Elphidium orbiculare and Elphidium excavatum 

alba are the most common species. Since the 

Holocene record is most complete, faunal changes 

are numerous and correspond to increasing water 

depths associated with the transgression. Shallowing is observed in several of the boreholes and 

related to the migration of the barrier islands or 

deltaic deposits. 

A COMPARISON OF NUMERICAL RESULTS OF 

ARCTIC SEA ICE MODELING 

WITH SATE LUTE IMAGES 

BY CHI-HAl LING AND CLAIRE PARKINSON1 

The results of a dynamic/thermodynamic numerical model of Arctic sea ice are being comp~ 

with satellite images from the Nimbus 5 electrically scanning microwave radiometer (ESMR). 

The model combines aspects of two previous sea 

ice models-those of Parkinson and Washington 

(1979) and Ling, Rasmussen, and Campbell (1980). 

It is a solid/fluid model basically following the formulation of the Parkinson and Washington model 

with the addition of the constitutive equation and 

equation of state from the Ling et al. model. 

The Parkinson and Washington model simulates 

the seasonal cycle of sea ice thicknesses and concentrations with a horizontal resolution of roughly 

200 km and a timestep of 8 hours. The thermodynamics are calculated through energy balances at 

the interfaces between ice and air, water and ice, 

and water and air. The ice dynamics are calculated 

through a momentum equation balancing air 

stress, water stress, dynamic topography, and 

Coriolis force, with an adjustment for internal ice 

resistance. This model has yielded results which 

compare favorably with observed Arctic and Antarctic sea ice variations. 

The Ling et al. model treats sea ice as a largescale fluid. It uses a viscous fluid constitutive 

equation that specifies the relationship between 

40 

stress and strain, and an equation of state that 

relates the sea ice pressure to the ice concentration, thickness, and velocity. It lacks a complete 

energy equation, although thermodynamic effects 

are treated parametrically. 

The numerical scheme of the combined model 

keeps track of the amount of ice entering each grid 

square. In locations with a net inflow of ice, the 

concentration increases according to the inflow 

values as long as the concentrations do not exceed 

99.5%. When calculated concentrations exceed 

99.5%, the Parkinson and Washington model reduces all inflow velocities to the relevant grid 

squares. The current model, however, with the 

Ling et al. formulation, retains the originally 

calculated ice velocities and appropriately thickens the ice to conserve ice volume. A fluid-type 

stress-strain relationship is used in the formulation of internal ice stress, in which the normal 

stress, or the sea ice pressure, is postulated to be 

proportional to the concentration and velocity 

convergence. The momentum equations, which are 

second order partial differential equations, are 

solved using successive over-relaxation and a ninepoint finite difference method. 

Atmospheric inputs are mean monthly surfaceair temperatures, surface dew points and sea level 

geostrophic winds from Jenne et al. (1969), while 

the initial ice extent is from the ESMR data for 

January 1, 1974. The ESMR sea ice extent data 

for the remainder of 197 4 is then used for comparison against the model results. Model calculations 

and ESMR data correspond well in the central 

Arctic but reflect the lack of oceanographic inputs 

in the marginal ice zone regions. For instance, the 

model fails to produce the prominent indentation 

of open water often observed along the west coast 

of Greenland, which is presumably due to the 

warm West Greenland current. 

1

Goddard Space Flight Centa', NASA. Greenbelt. Maryland. 

ARCTIC SEA ICE BY PASSIVE MICROWAVE 

OBSERVATIONS FROM THE NIMBUS-5 SATELLITE 

BY WILLIAM j. CAMPBELL, PER GLOERSONt, 

AND H. JAY ZWALLY2 

Observations made from 1972 to 1976 with the 

Electrically Scanning Microwave Radiometer 

(ESMR) on board the Nimbus 5 Satellite provide 

sequential synoptic information of the Arctic sea 
ice cover. This 4-year data set was used to construct a fairly continuous series of 3-day average 

19-GHz passive microwave images which has 

become a valuable source of polar information, 

yielding many anticipated and unanticipated discoveries of the sea ice canopy observed in its entirety through the clouds and during the polar 

night. Interpretation of the passive microwave 

satellite data set was performed by comparing 

selected sequential images with corresponding 

microwave profiles and images acquired by the 

NASA CV -990 airborne laboratory and with various "in situ" microwave and physical observations. These aircraft and surface microwave programs were performed as part of the Arctic Ice 

Dynamics Joint Experiments (AIDJEX) of 1972, 

75, and 76. Mesoscale microwave images of the 

AIDJEX manned drifting station array (Triangle) 

were obtained by aircraft during every season, and 

extensive aircraft transects covering major portions of the Arctic Basin in spring, summer, and 

fall. At the main camp within the AIDJEX triangle detailed multifrequency passive microwave 

observation, ice crystallographies, and dielectric 

properties were measured in three test areas with 

areas of approximately 1.5X104 m2

• 

Analysis of this three-level, three-resolution data 

set has shown how satellite passive microwave 

observations can be used to map key sea ice parameters on synoptic scales at time scales ranging from 

several days to interannual: ice edge position, ice 

concentration, multiyear ice, first-year ice, mixtures 

of these two ice types, and snow melt on the ice. 

Significant variations of ice concentration are found 

to occur in various parts of the Arctic during all 

seasons. During every August-September period of 

the 4 years ESMR operated, large areas of low 

microwave radiances, attributed to low ice concentration, formed deep within the ice pack. In 1972, 

73, and 76, these extensive zones of low ice concentration occurred generally along the Transpolar 

Drift Steam. The anomalous distribution was in 

1975 when they appeared in a ring of 85° N. cutting 

across the Beaufort Sea Gyre with another array 

along the Transpolar Drift Steam between the 

North Pole and East Greenland Sea. See figure 8. 

1

Goddard La00ratory for Atmospheric Sciences, Goddard Space Flight Center, 

Greenbelt, MD 20711. 

'Goddard Laboratory for Atmospheric Sciences, Goddard Space Flight Center, 

Tacoma, WA 98416. 

41 

LAND COVER AND TERRAIN MAPPING FOR THE 

DEVELOPMENT OF DIGITAL DATA BASES FOR 

WILDLIFE HABITAT ASSESSMENT IN THE YUKON 

FLATS NATIONAL WILDLIFE REFUGE, ALASKA 

BY MARK B. SHASBY1 , CARL MARKON2 , 

MICHAEL D. FLEMING1, DENNIS L. MURPHY1, 

AND JAMES E. YORK1 

The U.S. Geological Survey's EROS Field Office 

and the U.S. Fish and Wildlife Services's Refuges 

Division, both in Anchorage, Alaska, are currently 

working together on the use of Landsat multispectral scanner (MSS) data and digital elevation 

model (DEM) data to develop and test digital land 

cover and terrain data bases for assessing wildlife 

habitat in Alaska's National Wildlife Refuges 

(NWR). The inventory and assessment of resources for all NWR' s in Alaska are being carried 

out under the mandates of the Alaska National 

Interest Lands Conservation Act of 1980, which 

requires the development of a comprehensive management plan for each refuge by 1987. The work 

reported here was performed on the Yukon Flats 

NWR under an Interagency Support Agreement 

that provided for the cooperative development of 

land cover and terrain digital data bases. 

The Yukon Flats NWP consists of approximately 

8.63 million acres of land and water in the upper 

watershed of the Yukon River in northeastern 

Alaska. Portions of seven summer and five winter 

Landsat scenes were digitally registered to a 

127-meter Universal Transverse Mercator (UTM) 

grid and processed to derive land cover information 

for the refuge and an additional 4.5 million acres of 

adjacent lands. DEM data acquired from the U.S. 

Geological Survey's National Cartographic Information Center for the ten 1:250,00Q-scale USGS 

quadrangles comprising the study areas were 

mosaicked and registered to the same 127-meter 

UTM grid From the registered DEM data, slope 

and aspect information was derived to complete the 

terrain information portion of the data base. 

Landsat and DEM digital data were processed 

by computer in the EROS Field Office Digital 

Analysis Laboratory. Land cover was classified on 

summer Landsat MSS data utilizing a modified 

cluster-block approach followed by postclassification stratification. The winter Landsat data were 

used to more accurately identify water and riparian areas. Using terrain information (elevation, 

slope and aspect), certain spectral/information 
w 

1.!) 

(Y) 

1973 

1975 

kt?l Near Minimum Sea Ice Extent -

1974 

1976 

6 September 1973, 26 September 1974, 11 September 1975, 

11 September 1976 

~ Near Maximum Sea Ice Extent 

23 February 1973, 20 March 1974, 18 March 1975, 27 March 1976 

II Envelope of Low Microwave Ice Radiances during August and September. 

FIGURE 8.-Arcti.c sea ice parameters for 1973-76. 

classes were stratified into more meaningful map 

classes. 

The resultant digital data base containing land 

cover information and the three terrain variables 

provides a flexible tool for subsequent wildlife 

habitat assessment and resource inventory. Monitoring and assessment of waterfowl habitat and 

42 

waterfowl populations are of primary importance 

on the Yukon Flats Refuge. To address this information need, a computer-aided procedure for building a lake inventory data base was developed for 

assessing the current status of water bodies within 

the refuge and as a basis for future monitoring 

activities. 
The lake inventory data base is developed 

through a series of computer programs which extract all water bodies from the land cover layer of 

data in raster format, to produce a new layer comprised only of water, and then convert the raster 

file to a vector data file from which a data base file 

is produced. In the data base, each lake is identified with a unique number and is associated with 

the following variables: latitude and longitude 

coordinates for the centroid of each lake, surface 

area estimated in acres, and a water quality class 

based on sediment loads or depth derived in the 

Landsat-analysis phase of the project. Information from the data base can be queried and summarized based on user specified criteria For particular lakes or regions, additional data variables 

can be added or derived. Options exist for output 

in tabular form or in a plotted map format from 

the data base. Potential uses include investigations relating waterfowl population to lake densities, size, proximity to different cover types, and 

other parameters. These investigations will help 

managers gain a greater understanding of the resource they are managing. 

~echnicolol- Government Services, Inc., work performed under U.S. Geological 

Survey Cantzact Number 14-08-001-20129. 

~.s. Fish and Wildlife Service. 

GEOCHEMICAL DETECTION OF PROSPECTIVE 

PETROLEUM AREAS IN ARCTIC REGIONS 

BY A. A. ROBERTS, T. j. DONOVAN, 

J. D. HENDRICKS AND K. I. CUNNINGHAM 

Geochemical prospecting for petroleum is based 

on the premise that microseepage of compounds 

from oil and gas reservoirs does occur and that 

these compounds subsequently migrate to the 

Earth's surface. These techniques involve the 

detection of epigenetic alteration of near-surface 

rocks due to the presence of these seeping hydrocarbons, or the detection of alterations of the 

chemical composition of the near-surface soils and 

soil gases themselves. Two geochemical exploration techniques that have been developed for use in 

the contiguous United States have been investigated for their applicability in the permafrost environment of the Arctic coastal plain. 

The first of these involves the detection of 

anomalously high concentrations of the noble gas 

helium in near-surface permafrost. Owing to its 

small molecular size, chemical inertness, and ex43 

treme mobility, helium is one of the components of 

oil and gas reservoirs most likely to escape and 

subsequently migrate to the surface. Because 

helium is not of biogenic origin, its presence in 

anomalous concentrations near the surface is an 

indication of a subsurface source. Permafrost 

samples are collected and hermetically sealed in 

aluminum cans, leaving 5-10 cc of air above the 

sample. The helium in the permafrost is then 

allowed to equilibrate with the air in the head 

space. Subsequently, the helium in the head space 

is analyzed and the concentration of helium in the 

original sample is calculated through the use of 

corrections for temperature, pressure, pore 

volume, and water content. Normal concentrations 

of helium were observed in the permafrost overlying a variety of nonproductive areas in the National Petroleum Reserve in Alaska and in an area 

subsequently drilled as a dry hole. Abnormally 

high helium concentrations were observed on the 

Simpson Peninsula over the Simpson oil field and 

around the subsurface Simpson Canyon and are interpreted as being related to seepage of gases in 

areas where gently dipping Cretaceous strata have 

been truncated by the canyon. 

The second technique involves the detection of 

anomalous shallow-subsurface occurrences of magnetic minerals through the use of low-altitude 

(90 m), special purpose, aeromagnetic surveys. 

These magnetic materials are interpreted to be the 

result of chemical reduction of normally fully oxidized iron minerals to magnetite in the presence of 

seeping hydrocarbons. The magnetic contrast between typical sedimentary rocks and those enriched with this epigenetic magnetite results in 

distinctive high wave-number and low-amplitude 

total field anomalies. Detection of these shallow 

magnetic mineral occurrences is strongly enhanced through the use of a horizontal-gradient 

magnetic survey, which concurrently greatly 

reduces interpretation problems associated with 

diurnal variations and solar storms present at 

these high latitudes. Surveys over the Arctic 

Coastal Plain revealed magnetic anomalies over 

the Barrow gas fields, over the Simpson Canyon 

area of Cape Simpson, and slightly offshore in the 

Dease Inlet off the National Petroleum Reserve. In 

addition, surveys over the Arctic National Wildlife 

Refuge revealed a large area of anomalously high 

magnetic gradients over the Marsh Creek anticline 

suggesting that it may be a prime petroleum 

prospect. 
HYDROLOGY OF THE NORTH SLOPE, ALASKA 

BY CHARLES E. SLOAN 

The hydrology of the North Slope is dominated 

by the cold, dry climate and permafrost. Streamflow virtually ceases during the long winter. 

Precipitation occurs mainly as snow from September to May and is stored in the snowpack until 

breakup, a dynamic flow period in late May and 

early June. Most of the annual runoff occurs in the 

brief 2- to 3-week breakup period. The estimated 

mean annual runoff on the North Slope averages 

about 0.5 cubic feet per second per square mile and 

ranges from about 0.3 on the Coastal Plain to 

about 2.0 in the mountains. Peak flows usually occur during spring breakup when the height of the 

flood flow is significantly increased by the 

presence of ice jams. Maximum evident floods 

range from about 7 to 80 and average about 40 

cubic feet per second per square mile in large 

streams on the North Slope. 

The water quality of streams is generally excellent. However, during periods of high flow the 

streams carry high concentrations of suspended 

sediment and during periods of low or zero flow 

dissolved solids may become concentrated and the 

water may become depleted in dissolved oxygen. 

Lakes are the most conspicuous hydrologic feature on the North Slope, in places composing as 

much as 40 percent of the surface area of the 

Coastal Plain. The lakes range in size from Teshekpuk Lake which covers about 315 square miles, to 

small pounds of less than an acre. There are 

estimated to be more than 40,000 lakes greater 

than 1 acre in size in the. National Petroleum 

Reserve in Alaska (NPRA) alone. Most of the lakes 

on the Coastal Plain are shallow and freeze to the 

bottom during winter. Teshekpuk Lake is about 20 

feet deep and stores about 4 million acre feet of 

water, which is equivalent to about 2 years of 

average flow from the Colville River. A number of 

deep lakes to the south of Teshekpuk Lake range 

in depth from 20 to more than 70 feet. 

Water quality in the lakes is generally very 

good. Shallow lakes may become turbid when wind 

and wave action stirs up the bottom sediments. 

Glacial lakes in the mountains and southern foothills also have varying degrees of turbidity. In 

44 

shallow lakes that freeze nearly to the bottom the 

water can become so concentrated in dissolved 

solids by late winter that it would be unacceptable 

as a potable supply. 

The widespread occurrence of permafrost on the 

North Slope acts as an impervious barrier to the 

movement of ground water, limiting its availability, preventing the infiltration of surface water, 

and consequently accelerating runoff. Ground 

water is present beneath lakes and pools in rivers 

that do not freeze to the bottom. However, water 

in the fine-grained sediments beneath lakes is 

generally saline, and there is limited storage in the 

unfrozen sediments beneath deep river pools. Most 

water beneath the permafrost is also saline. Thawing of permafrost creates thaw lake depressions. 

Thermal erosion of ice-rich permafrost also leads 

to rapid and spectacular erosion of coastal bluffs 

and riverbanks, as well as rapid enlargement of 

lakes. 

A significant ground-water resource exists in 

carbonates of the Lisburne Group and in coarse 

clastic rocks of the Sadlerochit Formation in the 

eastern part of the Brooks Range near the mountain front. Numerous springs, some quite large, occur in this area. Sadlerochit Spring, which has a 

discharge of about 35 cubic feet per second, the 

Shublik Spring, which flows at about 25 cubic feet 

per second, are individual springs that flow from 

bedrock. Discharge from the springs freezes in 

winter to form large icings (aufeis). Icings are quite 

conspicuous and easily discernible on Landsat imagery. The source at springs can be found by going 

upstream from the icings. Tributaries of the 

Ivishak River, including the Echooka River, Flood 

Creek, Saviukviayak River, and the main stem of 

the Ivishak, have a cumulative discharge of more 

than 300 cubic feet per second from springs near 

the mountain front. 

Snow and ice are important as construction 

materials for roads, workpads, and airfields, and 

as sources of water supply. Snow accumulation 

can be managed through use of snow fences and 

other wind barriers that influence snow deposition. 

Snowfall may occur during any month of the year, 

but usually sticks to the ground starting in 

September and remains until late May or early 

June. Drifts along river and lake banks frequently 

persist until late summer. Lake and river ice attains an average thickness of about 6 feet by late 

winter and occasionally is 8 to 9 feet thick. 
PALEOGEOGRAPHIC AFFINITIES AND 

ENDEMISM 

OF CRETACEOUS AND PALEOCENE 

MARINE FAUNAS IN THE ARCTIC 

BY L. MARINCOVICH, JR., E. M. BROUWERS, 

D. M. HOPKINS 

The Arctic Ocean is the last of the world's 

oceans whose paleobiogeographic history is largely unknown. The general configuration of the Arctic Ocean and the presence or absence of major 

connecting seaways to the North Pacific and 

North Atlantic influenced the composition of Late 

Cretaceous and Cenozoic shallow-water arctic 

marine faunas. New finds of early Cenozoic marine 

faunas in onshore stratigraphic sections along the 

arctic margin of North America are providing 

fresh insights into the early history of the Arctic 

Ocean. 

An unusual assemblage of Paleogene mollusks, 

ostracodes, brachiopods, benthic foraminifers, 

dinoflagellates and palynomorphs occurs at Ocean 

Point, northern Alaska (fig. 9). The endemic nature 

of this assemblage suggests the possibility that 

the Arctic Ocean was not then in communication 

with the world ocean. Tentative correlation based 

on mollusks and ostracodes can be made with the 

early Paleocene Cannonball Formation of North 

and South Dakota, but not with some other approximately coeval northern high-latitude faunas; 

this suggests a geographically restricted arctic 

faunal realm. The molluscan and ostracode faunas 

of the Ocean Point and Cannonball deposits have 

relatively low species diversities, in strong contrast to the highly diverse approximately coeval 

faunas of tropical aspect in the Gulf of Mexico 

embayment, West Greenland (Disko), and northwestern Europe. Faunal composition and low 

ARCTIC OCEAN 

. ·' 

• l 

~ 

PACIFIC 

OCEAN 

/ 

CANNONBALL 

FM.OUTCROPS 

+ ~ SVALBARD 

·~ 

ATLANTIC OCEAN 

FIGURE 9.-Location of areas with Upper Cretaceous or Paleogene marine faunas noted in text. 

45 
species diversity suggest a temperate rather than 

tropical aspect for the Ocean Point and Cannonball faunas and imply a major separation of Arctic 

and Atlantic faunal realms in the early Tertiary. 

Paleogene molluscan faunas on Svalbard (fig. 9) 

are of moderate diversity and of probable Atlantic 

affinities. The Ocean Point and Cannonball beds 

are approximately coeval with the upper part of 

the Eureka Sound Formation of the Canadian Arctic Archipelago, which contains Paleocene and 

Eocene vertebrates, megaflora and pollen (West 

and others, 1981). Marine mollusks are known 

from the dominantly nonmarine Eureka Sound 

deposits on Ellesmere Island, but have not been 

extensively collected or studied, and are thought 

to be of relatively low diversity. Because the 

Eureka Sound Formation contains the thickest accumulation of arctic Paleogene deposits, study of 

its marine mega- and microfaunas is central to an 

understanding of the early Tertiary history of the 

Arctic Ocean. Sparse information available on 

Eureka Sound marine fossils allies them with the 

endemic low-diversity Ocean Point and Cannonball faunas and suggests that this formation was 

also deposited in an Arctic Ocean largely or entirely separated from the world ocean during part of 

the Paleogene. 

The history of connecting seaways between the 

Arctic and Pacific Oceans is poorly known. Most 

current plate-tectonic models suggest closure of 

marine connections between these oceans during 

the Late Cretaceous (Churkin and Trexler, 1981), 

although few paleontologic data are available to 

test this idea 

Paleontologic research done to date on Late 

Cretaceous and Paleogene marine faunas from the 

onshore arctic margin of North America has been 

limited by the small amount of collected fossils 

available for study. Still, the endemic character of 

the faunas is clear and supports the hypothesis of 

a geographically isolated Arctic Oce'an during 

some portion of Paleogene time. 

REFERENCES CITED 

Churki.n, M., Jr., and Trexler, J. H., Jr., 1981, Continental 

plates and accreted oceanic terranes in the arctic, in 

A. E. M. Nairn, M. Churkin, Jr., and F. G. Stehli, eds., The 

Ocean Basins and Margins, v. 5, The Arctic Ocean, Plenum 

Press, New York, pp. 1-20; 

46 

West, R. M., Dawson, M. R., Hickey, L. J., and Miall, A. D., 

1981, Upper Cretaceous and Paleogene sedimentary rocks, 

eastern Canadian Arctic and related North Atlantic areas, 

in J. W. Kerr and A. J. Fergusson, eds., Geology of the 

North Atlantic Borderlands: Canadian Society of 

Petroleum Geologists, Memoir 7, pp. 279-298. 

REMOTE SENSING STUDIES OF DYNAMIC 

ENVIRONMENTAL PHENOMENA IN ICELAND 

BY RICHARDS. WILLIAMS, JR 

In 1966, the U.S. Geological Survey (USGS) 

began a geological remote-sensing project in Iceland to study and to monitor various types of 

dynamic environmental phenomena By mid-1983, 

more than 50 abstracts, papers, and maps, mostly 

in collaboration with Icelandic scientists, have 

been or are about to be published on the following 

topics: thermal-infrared surveys of volcanoes and 

geothermal areas; volcanology; glaciology; geomorphology; geologic hazards, marine geology, 

and bibliography of the geological literature of 

Iceland. 

During the course of three aerial thermographic 

(airborne thermal-infrared) surveys, two by the Air 

Force Cambridge Research Laboratories in 1966 

and 1968 and one by the National Aeronautics and 

Space Administration in 1973, surface patterns of 

thermal emission were recorded of all of the known 

high-temperature geothermal areas and of several 

volcanoes in Iceland. In 1973, color and colorinfrared aerial photographs were also acquired. A 

series of preliminary papers on the analysis of the 

aerial thermographic data has been published, and 

preparation of a USGS Professional Paper, "Remote Sensing of High-Temperature Geothermal 

Areas of Iceland," in cooperation with the 

National Energy Authority of Iceland, is nearing 

completion. 

Volcanological studies have included analysis of 

thermal data of an effusive eruption on Surtsey 

recorded by the Nimbus 2 spacecraft and publication of a USGS scientific leaflet on diversion of 

lava by water cooling during the course of the 

eruption of Eldfell on Heimaey, Vestmannaeyjar, 

Iceland. Satellite imagery of Iceland's glaciers 

established that variations in the termini of ice 

caps and outlet glaciers could be measured by 

Landsat imagery. This research provided the 

catalyst for the initiation, in 1977, of a USGssponsored international project to prepare a 
"Satellite Image Atlas of Glaciers (of the World)." 

Analysis of satellite imagery resulted in the 

publication of two 1:500,000-scale Landsat image 

maps of Vatnajokull ice cap, preparation of a 

special computer-enhanced image, and new knowledge about poorly known or unknown glaciological, structural, and tectonic features under and 

adjacent to the Vatnajokull ice cap. 

Geomorphological research involved the use of 

aerial thermographs and color-infrared aerial 

photographs to map periglacial phenomena in Iceland, including frost-crack polygons and palsas 

(frost mounds). Comparative planetology studies 

established that concentric ridges on the Arsia 

Mons volcano on Mars are best explained by the 

analog of recessional moraines in Iceland. Moreover, comparative planetology research, in a joint 

effort with the late Sigurdur Thorarinsson and 

Elliot C. Morris, resulted in a new classification for 

the 27 types of Iceland's volcanoes. The classification is based on the nature of the volcanic activity, 

environment during formation, and configuration 

of feeder conduit, for the three primary compositional classes of Icelandic volcanoes. 

A new classification scheme has been developed 

for the four principal geologic hazards of Iceland: 

geomorphic, geothermic, seismic, and volcanic. 

Historically, seismic (earthquakes and rifting) and 

volcanic (lava flows, tephra falls, volcanic gases, 

maars (explosion craters), jokulhlaups (glacieroutburst floods), and other floods) hazards have 

had the most impact on Iceland and its people. 

In marine geology, analysis of a Landsat multispectral scanner (MSS) band 4 image off the southwest coast of Iceland has revealed the complex 

pattern of coastal currents in this area, including 

eight large eddies (40 km in diameter), all apparently made visible by variations in the concentration of phytoplankton in near-surface waters. 

A "Bibliography of the Geological Literature of · 

Iceland: 1777-1983" is also nearing completion, 

with approximately 5,000 citations already prepared and indexed. The multilanguage geoscience 

literature of Iceland is particularly rich in the 

topics of volcanology, goethermal activity, geochemistry, geophysics, tectonics, tephrochronology, glaciology, petrology, and geologic hazards, 

and having the extant literature available in English will make it more widely known to Englishspeaking scientists. 

47 

CORRELATION OF LATE CENOZOIC MARINE 

TRANSGRESSIONS OF THE ARCTIC COASTAL 

PLAIN 

WITH THOSE IN WESTERN ALASKA AND 

NORTHEASTERN RUSSIA 

BY JULIE K. BRIGHAM 

Six distinct marine transgressions of Pliocene (?) 

and Pleistocene age have been differentiated 

within the Gubik Formation across the western 

part of the Alaskan Arctic Coastal Plain (fig. 10; 

Brigham, 1983). The recognition of these superimposed but lithologically similar marine units is 

based on the detailed stratigraphic study of unconsolidated sediment in coastal and river-bluff 

exposures and the amino-acid geochemistry of 

mollusks from these deposits (table 1). The extent 

of isoleucine epimerization (alle/Ile) in free 

(naturally hydrolyzed)- and total (free plus peptide 

bound)- amino-acid fractions in Hiatella arctica 

(Linne), Mya truncata Linne, and M arenaria 

Linne from Gubik deposits cluster into groups of 

ratios that differentiate temporally distinct highsea-level events (table 2). 

Amino-acid data have also been acquired from 

mollusks representing the transgressions documented by Hopkins (1967, 1973) along the west 

coast of Alaska and from similar sequences described on the Soviet coasts of the Bering and 

Chukchi Seas (Petrov, 1966, 1976, 1982; Khoreva, 

1974). Aile/lie ratios (G. H. Miller, unpublished 

data, 1976) inHiatella andMya provided by D. M. 

Hopkins from the Nome region approach racemic 

equilibrium in the free-amino-acid fraction of the 

oldest unit (table 2). Similarly, alle/Ile ratios in 

shells from the Soviet coast (provided by 0. M. 

Petrov, Geological Institute of Moscow) gradually 

increase over time (table 2; Brigham, 1981). In 

general, the higher alle/Ile ratios in mollusks from 

the Kamchatka deposits reflect more rapid epimerization resulting from the relatively warmer thermal regime (current mean annual air temperature, 

CMAT, -0.9 to 1.5°C) affecting the peninsula 

throughout the late Cenozoic. Latitudinal temperature gradients along the Soviet and Alaskan 

coasts today are sharp (1.4°C per degree of latitude), although the Soviet shore averages 2 o -6 oc 

cooler than the Alaskan coast at similar latitudes. 

All the sites sampled, except those from Kamchatka, lost most of their maritime influence during 
ARCTIC OCEAN 

li, 

COMMANDER ISLANDS 

CHUKCHI 

SEA 

BERING SEA 

ST. PAUL I. • PRIBILOF IS. 

ST. GEORGE 1. • 

, . 

• 

300 KM 

FIGURE 10.-Westem Alaska and northeastern Russia, showing locations of sample sites (shaded areas) on either side of the 

Bering and Chukchi Seas. 

the glacial episodes of low sea level and presumably had significantly lower mean annual temperatures (e.g., Brigham and Miller, 1983). 

The correlation of marine units within Alaska 

and across the Bering Strait to the Kamchatka 

and Chukotka Peninsulas (table 3, fig. 11) is based 

on the relative differences in alle/Ile ratios and on 

assumptions concerning the integrated thermal 

history of the samples since deposition. The low 

alle/Ile ratios suggest that the Attarmen beds of 

Kamchatka may be only 35,000-40,000 yr old, 

rather than 125,000 yr old as suggested by 

Hopkins (1973), Gladenkov (1981), and Petrov 

(1966, 1982). If the Attarmen beds are assumed to 

be as old as 125,000 yr, then the alle/Ile ratios require an effective diagenetic temperature of -9°C, 

some 8 oc cooler than today. This thermal term 

seems much too cold, especially in light of 

CLIMAP (Climate/Long Range Investigation, 

Mapping and Predictions) reconstructions for the 

North Pacific (Moore et al., 1980) that indicate seasurface temperatures only about 2°C cooler than 

those 18,000 yr B.P. 

48 

A major middle Pleistocene interglacial trans~ 

gression is recognized along numerous reaches of 

the Bering and Chukchi Seas, as indicated by the 

Kotzebuan, Karmuk, Karaginsk, and Pinakul' marine units (table 3). 

The los alle/Ile ratios in shells from the Pinakul' 

suite off Siberia (0.035, total) preclude the correlation by Khoreva (1974), who suggested that this 

suite correlated with the highly epimerized Alaskan Anvilian deposits (0.47, total). Moreover, similar alle/Ile ratios in shells from the V al'katlen, 

Kresta, and Pinakul' beds suggest that any age 

differences between these beds are small. 

The correlation of deposits older than middle 

Pleistocene, however, is less certain. Alle/Ile ratios 

in the upper (0.22, total) and lower (1.04, total) 

parts of the Olkhovaya suite on the Kamchatka 

Peninsula indicate that this unit spans a great deal 

of Pliocene and Pleistocene time. The lower part of 

the Olkhovaya suite is probably much older than 

the Beringian transgression in western Alaska, 

especially in comparison with total-amino-acid 

ratios in Pliocene shells from Britain (CMAT, 
TABLE 1. Pliocene and Pleistocene marine stratigraphy and sea level history of the Gubik Formation on 

the Alaskan Arctic Coastal Plain west of Barrow, Alaska 

Informal 

units 

of 

Gubik Fm. 

(youngest 

deposits) 

unit not 

preserved 

along Chukchi 

Sea Coast 

Walakpa 

beds 

Karmuk 

beds 

Tuapaktushak 

beds 

Ki 11 i Creek 

Nul av ik 

Stratigraphic 

Position 

(Locations, Fig. 1) 

Distribution limited to 

Beaufort Sea coast at 

<7 m above sea level 

Extensive beach and 

barrier deposits at 

Barrow, Wal akpa Bay, 

Wainwright, and coast 

south of Wainwright up 

to 12 m above sea level 

Blankets the upper half 

of bluffs along parts 

of Skull Cliff, deposits 

at Karmuk Pt., and beach 

deposits 30-33 m above 

sea level south of Icy 

Cape. Reworked shells 

in alluvium 25 km south 

of Atkasook. Unit 

1 ocall y folded 

Extensive exposures 

along Skull Cliff, 

between Barrow and 

Peard Bay; also near 

Mi 1 imankav i, south of 

Wainwright; reworked 

shell samples at 60 

m above sea level along 

Kukpowrik River. Unit 

locally folded 

Discontinu~us basal 

marine unit along 

Skull Cliff. Extent 

above present sea 

1 evel unknown 

Discontinuous basal 

marine unit along 

Skull Cliff. Transgressive extent 

unknown 

Marine 

Environment 

Arctic waters 

similar to 

today 

Marine 

environment 

slightly 

warmer than 

today. 

Numerous 

extral imital 

species 

Arctic waters 

like today; 

no extra1 imita 1 or 

extinct 

·species 

Marine conditions 

much warmer than 

today; includes 

several extinct 

mollusk and 

ostracode 

forms, as well as 

extremely extralimital species 

do. 

conditions 

not well 

doc 110ented 

49 

Estimated 

Age 

(years) 

aojooo105,000 

120,000-

125,000 

250,000-

500,000 

? 

1,700,000-

2,200,000 

2.5-3.5 m.y. 

Evidence for 

Age 

Carrel at ion with 

Western Alaska 

(Hopkins 1967, 

Correlation 

with oxygen-

; sotope record 

beyond radiocarbon dating 

1973 

Amino-acid age Pelukian 

estimate; associated with 

relatively warm 

fauna; correlation with 

oxygen-isotope 

record; beyond 

radiocarbon 

dating 

Jlm i no-acid age Kot zebu an 

estimate; 

tentative 

correlation 

with Kotzebuan 

that is K-Ar 

dated at •250,000 yr 

? 

Simi 1 ar faunal Probably 

elements and Anv i 1 ian 

stage of evolution of fossi 1 

sea otter found 

in deposits at 

Ocean Pt. with 

similar aile/Ile 

ratios (L.D. Carter, 

unpublished data, 

1982) 

Differentiated Beringian 

only on the basis 

of aile/Ile ratios. 

Oldest unit recognized therefore 

carrel ated with 
Table 2. Aminostratigraphy of marine transgressions in northwestern 

and western Alaska and on the Kamchatka and Chukotka 

Peninsulas, U.S.S.R. 

Unit S . 1 pec1es 

analyzed 

Modern ------------ Ha 

Walakpa beds ------ Ha 

Ma 

Karmuk beds ------- Ha 

Mt-Ma 

Tuapaktushak beds - Ha 

Mt-Ma 

Killi Creek beds -- Ha 

Mt-Ma 

Nulavik beds ------ Ha 

Pelukian ---------- Ha 

Mt 

Kotzebuan --------- Mt 

Anvilian ---------- Ha 

Beringian --------- Ha 

Mt 

Val'katlen beds--- Mt 

Kresta suite ------ Ha 

Mt 

Pinakul suite ----- Ha 

Mt 

= 

No. of valves 2 aile/ I 1 e 

FREE TOTAL 

northwestern Alaska (CMAT, -10° to -13°C) 

3 

16 

2 

26 

19 

4 

15 

4 

3 

3 

NO 

NO 

0. 40±0. 052 

0. 37±0. 085 

0. 51±0. 025 

0. 54±0. 057 

0. 50±0. 072 

0. 52± o. 057 

o. 75±0. 067 

0.011±0.002 

0.014±0.002 

0.018±0.001 

0.038±0.007 

0.038±0.006 

0.086±0.009 

0.086±0.013 

0.15±0.007 

0.15±0. 023 

0.23±0.016 

Nome, western Alaska (CMAT, -4.7°C) 

2 

4 

2 

3 

3 

2 

0.16±0. 001 

0. 28±0. 03 

o. 46±0. 04 

0. 90±0. 02 

1. 04±0. 03 

o. 94±0. 03 

0.040±0.002 

0.042±0.005 

0.093±0.001 

0.47±0.03 

0.56±0.07 

0. 56±0. 04 

Chukotka Peninsula (CMAT, -7.5° to -10°C) 

3 

1 

2 

1 

1 

0.17±0. 011 

0.23 

0. 22± 0. 02 

0.26 

0.21 

0. 018±0. 002 

0.022 

0. 020±0. 002 

0.031 

0.035 

Kamchatka Peninsula (CMAT, -0.9° to -1.5°C) 

Attarmen beds ----- Ha 

Mt 

Karaginsk beds ---- Mt 

Upper 01 khov aya 

suite 

T us at uv i am bed s 

Lower 01 khov aya 

suite 

Mt 

Mt 

Ha 

Mt 

1 

1 

3 

3 

2 

2 

2 

0.17 

0.14 

0. 43± 0. 05 

0. 44± 0. 01 

1.16±0. 03 

1. 38±0. 03 

1. 28±0. 03 

0.038 

0.027 

0.115±0. 013 

0. 22 ±Q. 012 

o. 577±0. 004 

1. 04 ±Q. 06 

1. 04 ±Q. 05 

Ha, Hiatella arctica; Mt, Mya truncata; Ma, Mya arenaria; Mt-Ma, 

2 Mya truncata and M. arenarTa results combined 

3 Values represent the mean ±16 for peak-height measurements. 

NO, not detectab 1 e . 
Table 3. Aminostratigraphic correlation of late Cenozoic marinetransgressive units across the Bering and Chukchi Seas 

Estimated 

Abso 1 ute 

Age (m.y.) 

0.035-0.040 

0.08-0.100 

0.125 

0.150 

0. 25-0.50 

? 

1. 7-2. 2 

Kamchatka, 

U.S.S.R. 

Attarmen beds 

? 

Karaginsk 

Upper 01 khov aya 

(?) suite 

Tusatuv i am(?) 

beds 

Chukotka, 

U.S.S.R. 

Val' kat len 

Kresta 

Pin akul' 

(no older 

samples 

Nome, 

W. Alaska 

Pe 1 uki an 

Kotzebuan 

Anv i 1 ian 

Coastal Plain, 

NN. Alaska 

Youngest deposits 

Walakpa beds 

Karmuk beds 

Tuapaktushak beds 

Ki 11 i Creek beds 

2.5-3.5 ana 1 yzed) Bering ian Nu 1 av i k beds 

>3.0 Lower 01 khov aya 

suite 

+ l0°C) of 1.20±0.002 (Miller et al., 1979). This interpretation differs from the correlation proposed 

by Gladenkov (1981, p. 20), who equated the entire 

Olkhovaya suite with marine deposits younger 

than the Anvilian transgression. 

REFERENCES 

Brigham, J. K., 1981, Amino acid geochronology of late Pliocene and Pleistocene marine transgressions on the Arctic 

Coastal Plain, northwestern Alaska: Geological Society of 

America Abstracts with Programs, v. 13, no. 7, p. 417. 

Brigham, J. K., 1983, Marine stratigraphy, amino acid geochronology, and sea level history of the Gubik Formation, 

Arctic Coastal Plain, northwestern Alaska, Ph.D. dissertation, University of Colorado, available December, 1983. 

Brigham, J. K., and Miller, G. H., 1983, Paleotemperature estimates of the Alaskan Coastal Plain during the last 125,000 

years: Proceedings of the Foorth International Conference 

on Permafrost, Fairbanks, National Academy of Science, 

in press. 

Gladenkov, Y. B., 1981, Marine Plio-Pleistocene of Iceland and 

the problems of its oonelation: Quaternary Research, v. 15, 

p.18-23. 

Hopkins, D. M., 1967, Quaternary marine transgressions in 

51 

Alaska, in Hopkins, D. M. (ed.), The Bering Land Bridge: 

Stanford University Press, p. 4 7-86. 

Hopkins, D. M., 1973, Sea level history in Beringia during the 

past 250,000 years: Quaternary Research, v. 3, p. 520-540. 

Khoreva, I. M., 1974, Stratigraphy and Foraminifera of the 

Marine Quaternary Deposits of the west shore of the Bering Sea, Akademy Nauk USSR Geologic Institute, v. 225, 

152p. 

Miller, G. H., Hollin, J. T., and Andrews, J. T., 1979, Aminostratigraphy of UK Pleistocene deposits: Nature, v. 1981, 

p. 539-543. 

Moore, T. C., Jr., Burckle, L. H., Geitzenauer, K., Luz, B., 

Molina-Cruz, A., Robertson, J. H., Sachs, H., Sancetta, C., 

Thiede, J., Thompson, P., Wenham, C., 1980, The reconstruction of sea surface temperatures in the Pacific Ocean 

of 18,000 B.P.: Marine Micropaleontology, v. 5, p. 215-247. 

Petrov, 0. M., 1966, Stratigraphy and fauna of marine mollusks in the Quaternary deposits of the Chukotsk Peninsula: Akademy Nauk USSR, Geological Institute Trudy 

115, Iad-vo "Nauka", Moscow, 288 p. In Russian. 

Petrov, 0. M., 1967, Paleogeography of Chukotka during Late 

Neogene and Quaternary time, in Hopkins, D. M. (ed.), The 

Bering Land Bridge, Stanford University Press, 

p.144-171. 

Petrov, 0. M., 1982, Marine mollusks of the Anthropogene 

from the northern region of the Pacific, "Nauka", v. 357, 

144 p. In Russian. 
1.0 

:; 0.9 

cC 

t-

~ 0.8 ...._, 

0 t= 0.7 

cC 

a: 

CD 0.6 

...... 

..! 0.5 

a; 

0.4 

0.3 GUBIK FM. 

0.2 e -?-- - NULAVIK BEDS ---- 0.1 ----e----

0.05 

e- KILLI CREEK BEDS 

------9 ... TUAPAKTUSHAK BEDS =====-...._~._...--._... _______ ~ KARMUKBEOS ~ W ALAKPA BEDS 

2 0 -2 -4 -6 -8 -10 -12 -14 

CURRENT MEAN ANNUAL AIR TEMPERATURE ( °C) 

FIGURE 11.-Tentative COITelation of transgressive marine units between Alaska and northeastern Russia, based on total-amino 

acid alle/Ile ratio plotted against current mean annual temperature. 

ABSTRACTS NOT PRESENTED 

AT THE SYMPOSIUM 

POSSIBLE ORIGINS OF PLACER GOLD IN 

KOVUKUK AND CHANDALAR DISTRICTS, 

BROOKS RANGE, ALASKA 

BY JOHN C. ANTWEILER, JOHN R. WATIERSON, 

JOHN B. CATHRALL, AND ELWIN L. MOSIER 

In regions of permafrost, gold nuggets may form 

when mineral or organic acids dissolve, transport, 

and then deposit finely divided gold on spores of 

psychrophilic (cold-loving) bacteria. As an example, in the Kovukuk and Chandalar districts, 

Brooks Range, Alaska, gold-quartz-antim()nyarsenic-sulfide veins have been suggested as, the 

source of gold in a number of placer deposits. In 

addition to the gold-bearing veins, gold often occurs as tiny particles disseminated in schists .and 

in igneous rocks such as diorites. There, as elsewhere in Alaska, gold in those veins is of smaller 

grain size than that in the placers and is also of 

52 

much lower fineness. Typically, grains of gold in 

the veins occur as small, discontinuous blebs, 

wires, stringers, or crystals that weigh only a few 

milligrams at most and have a fineness of 

800-825. Nuggets in nearby placers, however, 

sometimes exceed an ounce in weight and have a 

fineness of 900-970. 

Finely disseminated gold that occurs in schists, 

veins, stringers, and blebs in many Alaskan gold 

fields can be dissolved by several agents. These include cyanogenic compounds in organic materials, 

organic acids in the layer of humus-rich muskeg 

over permafrost and bedrock exposures, and sulfuric acid with traces of arsenic and antimony in 

pyrite-rich zones. In addition, various microbiological processes may contribute to the solubilization of gold. 

The spores of bacteria can precipitate gold from 

solution. In laboratory experiments, suspensions of 

BaciUus cereus spores added to 1,000 micrograms/ 

milliliter solutions of gold chloride have been 

shown to bind gold chemically. They have also 
been shown to be nucleation centers for the growth 

of microscopic 8- and 12-sided gold polygons 

similar to small crystalline gold nuggets found in 

placers. X -ray diffraction and scanning electron 

microscope confirmed the crystalline nature of 

gold fixed to bacterial spores. 

We therefore propose the following: finely divided gold may be solubilized in several ways and 

is carried to solution through channels or fractures 

in permanently frozen ground. The same channels 

may also transport psychrophilic bacteria that 

thrive at temperatures near 0°C. The spores of 

these bacteria at favorable sites may be nucleation 

centers for the growth of crystalline gold nuggets. 

PERMAFROST STUDIES IN ALASKA 

BY ROBERT F. BLACK1 

During the period 1945-1952 detailed studies of 

permafrost were carried on in central and northern 

Alaska, and reconnaissance was made of many 

areas throughout the region. The main focus of the 

initial work was to resolve the opposing viewpoints of E. de K. Leffingwell and Stephen Taber. 

Leffingwell in 1919 published the contraction 

hypothesis for origin of ice wedges in permafrost. 

In this concept ice wedges at the top of the permafrost table were initiated by ground-contraction 

cracking in early winter, the cracks filling with 

snow, hoar frost, and freezing water during the 

spring thaw. Moisture came from the atmosphere 

and surface. Taber in 1943, however, denied this 

was an active process and proposed that the ice 

wedges were fossil features that grew at the time 

of the formation of the permafrost by water being 

drawn up from below. Thus, the age, significance, 

and engineering implications of the ice wedges 

were thrown into doubt. 

It is interesting to note that Leffingwell's study 

was done over a period of many years while he 

lived year-around in extreme northern Alaska-a 

region of continuous permafrost. In contrast, 

Taber's work had been concentrated on seasonal 

frost in connection with highway construction and 

maintenance and on simple laboratory experiments with the freezing of small samples. His one 

summer in Alaska was confined essentially to the 

discontinuous and sporadic zones of permafrost-a 

time when the contraction cracks of the previous 

winter were obscured by thaw and luxuriant 

- vegetation. 

53 

The need for quick assessment of permafrost 

conditions during World War II demanded better 

understanding of the age and origin of the processes involved in the growth of ice in the ground 

and of the significance of surface features, particularly polygonal patterns, in evaluating the 

character of the permafrost. My work through the 

change in seasons at Barrow substantiated fully 

the observations and interpretations of Leffingwell. Precise measurements of ground contraction 

showed that the ground responded to temperature 

changes as would be expected and that cracking 

and partial filling did occur. The average rate of 

growth in width of the ice wedges was about 1 mrn/ 

year. Modified techniques and equipment of 

glaciologists and petrologists also were used to 

prepare and study numerous thin sections of the 

ground ice. Interpretation of the detailed fabrics of 

ice wedges corroborated and reconstruction of 

their manner of growth and of the thermal stresses 

and strains that took place seasonally. 

Buried, inactive ice wedges also were studied in 

the field and laboratory, but they were not amenable to dating in those earlier years. Samples for 

radiocarbon dating, collected recently in northern 

Alaska, show the wedges to be very old, probably 

spanning most if not all the Wisconsinan Stage. 

The deeply truncated roots of buried wedges are 

rising very slowly, like diapirs, because of horizontal stresses from the growth of large surface 

wedges and from thermal changes. The permafrost 

is active in its upper part. 

A knowledge of ice wedges in Alaska has aided 

immeasurably in identifying true ice-wedge casts 

in the temperature regions of the United States. 

Permafrost climates associated with the margins 

of former ice sheets have been postulated on the 

basis of wedge structures that have been misidentified in many places, such as southern New 

England. 

1

Department of Geology and Geophysics, University of Connecticut, Storrs, CT 

06268. 

PLEISTOCENE OF NORTHERN GREENLAND 

BY WILLIAM E. DAVIES 

North of 79 degrees, a zone of ice-free land, 100 to 

200 km wide, extends across the north part of 

Greenland. In this area are coastal alpine mountains south of which are high, dissected plateaus. 

The land is segmented by long fjords extending 

from the sea to the inland ice sheet. 
In the area of ice-free land there is evidence of 

three pre-late Wisconsinan glacial advances. The 

features related to the oldest advance and retreat 

are numerous ice-marginal channels that are not in 

accord with the geometry of features developed by 

later Wisconsin glacial events. A later stage of 

glaciation is in Knud Rasmussen Land north of 

Hyde Fjord where the mountains are cut by interconnected cirques many of which have been truncated at their heads or toes by younger glaciers 

moving across them. Some were buried by later ice 

sheets and at present are partially exhumed or are 

recognizable from the surface configuration of the 

ice cover. 

Two large terminal moraines extend along Independence Fjord in the vicinity of Hagen and Danmark Fjords. The northernmost is a ridge over 

50 km long and up to 200 m high formed of unweathered clayey and silty sand with cobbles and 

boulders. Bordering this moraine to the south is 

one of similar but deeply weathered material which 

has been planed off by overriding of more recent 

glaciers. 

During Wisconsinan glaciation there were six 

major ice centers. The inland ice sheet of Greenland expanded north to Independence Fjord, J.P. 

Koch Fjord and westward towards Nares Strait. 

The ice sheet in Nares Strait and to the north did 

not connect with the one on Ellesmere Island and 

only snouts of valley glaciers extended into the 

strait. The ice caps of Hans Tausen Land and 

Nordkronnen expanded southwards coalescing 

with and buffering the inland ice sheet in Independence Fjord as well as moving northeastward down Hyde Fjord. North of Hyde Fjord 

there is no evidence of extensive overriding by an 

ice cap. At the time of maximum extent of glaciers 

there were extensive mountain icefields with 

valley glaciers coalescing to form piedmont 

glaciers along the north coast of Greenland. The 

center of another local ice cap was on the north 

side of Hyde Fjord near its mouth. Similar conditions existed in a greatly expanded Flade Isblink 

east of the mouth of Danmark Fjord. The area between Independence and Hyde Fjords appears to 

have been free of ice cover, and there remain a 

number of high level, interlaced valleys that carried meltwater from the ice sheet to the Greenland 

Sea. 

Based on marine terraces, the retreat of the ice 

in Nares Strait and to the north began 7,000 to 

8,000 years B.P. During the retreat of the inland 

54 

ice sheet and smaller ice caps, movement from the 

ice centers was concentrated in long valley glaciers 

occupying the major valleys. Successive retreatal 

positions follow valleys and are more or less parallel to present ice fronts. Uplift since retreat began 

varies from 25 m on the northern Arctic coast to a 

maximum of 129 m between Independence and 

Hyde Fjords. 

During retreat of the ice, varved clay and silt 

deposits 20 m or more thick were laid down in 

most of the large, interconnecting valleys in lakes 

formed behind ice-tongue dams. Extensive marine 

deposits formed along the coast of the Greenland 

Sea and were reworked into seven main levels of 

raised beaches and delta terraces. End moraines 

are well developed in valleys and on coastal plains 

but are generally not well developed on the upland. 

THERMODYNAMICS AND OCEANOGRAPHY 

OF THE SEA ICE EDGE 

BY EDWARD G. JOSBERGER 

Sea ice melting at the ice edge is one of the 

primary processes that determines the ice edge 

position; the melting results from the upward heat 

flux from the underlying upper ocean. The melting 

process occurs during both the winter and the 

summer because the adjacent open ocean in the 

Marginal Ice Zone (MIZ) is at a temperature above 

the salinity determined freezing point. The ice is 

then either blown out into this relatively warm 

water or this water flows under the ice. This 

melting produces the large horizontal gradients of 

temperature and salinity that characterize the 

MIZ. Melt rate measurements from the winter 

Bering Sea and the summer Greenland Sea show 

that the melt rates reach 20 mm per hour for 

typical upper ocean temperature, salinity and 

velocity conditions. Figure 12 shows the melt rates 

and sea water temperature and speed 2 m below 

the ice from the winter Bering Sea experiment. 

A properly formulated model of ice melting in 

sea water must include the eutectic relationship 

between temperature and salinity and both the 

heat and salt transfer from the underlying upper 

ocean. The results of such a model show the following: first, the ice-sea water interface temperature 

is within 10% of the far-field salinity determined 

freezing point not at 0°C nor at the far-field freezing point; second, the melting rates are of the 

order of 1 m/day; finally, the effect of the melting 

on the upper ocean dynamics, as characterized by 
the Obukov length, are minimized by the upward 

salt flux reaching the ice. In this case the Obukov 

lengths are greater than the planetary boundary 

layer depth. 

+1 

30 

iii 0 e :§: 

.£ 20 I- ::J 

-1 

10 

-2 

10 20 

TIME (hrs) 

FIGURE 12.-Ice thickness, ocean temperature, and ocean speed 

taken during the Bering Sea MIZEX experiment, February 1983. The closing of switches set at increasing depths 

in the ice gave the ice thickness during the experiment. A 

current meter suspended 2.5 m below the ice gave the 

ocean temperature and speed. Initially the ice was in water 

at -1 oc and was melting at 7 mm/hr. Then the ice moved 

into water at + 1 °C, and the melting increased to 

20mm/hr. 

55 *U.S. GOVERNMENT PRINTING OFFICE:l98J-226-S/579