DiStributton of Clay nerals 

in the Susp ded Bottom 

Sediments fnom the Northern 

Bering Sea Shel.f Area t Alaska 

Distribution of Clay Minerals 

in the Suspended and Bottom 

Sediments from the Northern 

Bering Sea Shelf Area, Alaska 

By FREDRIKA C. MOSER and JAMES R. HEIN 

U.S. GEOlOGICAl SURVEY BUllETIN 1624 
DEPARTMENT OF THE INTERIOR 

WILLIAM P. CLARK, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE 1984 

For sale by the 

Distribution Branch, Text Products Section 

U.S. Geological Survey 

604 South Pickett St. 

Alexandria, VA 22304 

Library of Congress Cataloging in Publication Data 

Moser, Fredrika C. 

Distribution of clay minerals in the suspended and bottom 

sediments from the northern Bering Sea shelf area, Alaska 

(U.S. Geological Survey Bulletin 1624) 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1624 

1. Clay minerals-Alaska-Norton Sound. 2.Clay mineralsBering Sea. 3. Marine sediments-Norton Sound (Alaska). 

4. Marine sediments-Bering Sea. I. Hein, James R. II. 

Title. Ill. Series: United States. Geological Survey. Bulletin 

1624. 

QE75.B9 no. 1624 

[QE389.625] 

549'.6 84--600159 
CONTENTS 

Abstract 

Introduction 

Acknowledgments 

Regional setting 1 

Bathymetry 1 

Major currents 1 

Major sources and dispersal of sediments 2 

Geology 3 

Methods 4 

Distribution of sediment 5 

Bottom sediment 5 

Norton Sound 5 

Northern Bering Sea shallows and Chirikov Basin 5 

Suspended sediment 6 

Yukon River 7 

Kuskokwim River 8 

Sediment sources and dispersal routes 8 

Bottom sediment 9 

Suspended sediment 11 

Inferred current patterns 13 

Environmental considerations 13 

References 14 

FIGURES 

1-15. Maps showing: 

1. Location of study area 2 

2. Water circulation in northeastern Bering Sea 

and southern Chukchi Sea 3 

3. Distribution of chlorite and kaolinite in 

bottom sediment 4 

4. Distribution of illite in bottom sediment 6 

5. Distribution of smectite in bottom sediment 7 

6. Distribution of chlorite and kaolinite in 

suspended sediment 8 

7. Distribution of illite in suspended sediment 9 

8. Distribution of smectite in suspended sediment 12 

9. Distribution of chlorite and kaolinite in nearsurface suspended sediment 13 

10. Distribution of illite in near-surface 

suspended sediment 14 

TABLES 

11. Distribution of smectite in near-surface 

suspended sediment 15 

12. Distribution of chlorite and kaolinite in nearbottom suspended sediment 16 

13. Distribution of illite in near-bottom suspended 

sediment 17 

14. Distribution of smectite in near-bottom 

suspended sediment 18 

15. Isopach of Holocene marine sediment in Norton 

Sound 19 

1. Clay-mineral percentages in sediment from the Yukon 

and Kuskokwim Rivers 10 

2. Average and range of clay-mineral percentages of 

bottom- and suspended-sediment samples from Norton 

Sound and adjacent Bering shelf 11 

III 

Distribution of Clay Minerals in the Suspended and Bottom 

Sediments from the Northern Bering Sea Shelf Area, Alaska 

By Fredrika C. Moser and James R. Hein 

ABSTRACT 

Analysis of the clay mineralogy of bottom and 

suspended sediment from Norton Sound and the adjacent 

Bering Sea shelf and from the Yukon and Kuskokwim 

Rivers suggests possible source areas, dispersal routes, 

and current patterns. Source areas include the Yukon and 

Kuskokwim Rivers, and possibly sites to the south or 

west. 

On June 20, 1975, clay mineralogy in the Yukon and 

Kuskokwim Rivers, respectively, averaged 50 and 52 

percent illite, 48 and 48 percent chlorite+kaolinite, and 2 

and 1 percent smectite. During the summer months of 

1968-70 and 1976-77, the suspended sediment, which 

indicates short-term sediment supply, averaged 1 

percent smectite, and the bottom sediment, which 

represents longer term deposition, averaged 21 percent 

smectite. Thus, smectite may be supplied to the northern 

shelf from a source to the south or west, perhaps the 

Aleutian Ridge or Chukotka Peninsula region of the 

U.S.S.R. In addition, the clay mineralogy of the Yukon 

River may change seasonally or annually; our sampling of 

the river represents only one moment in time. The 

detailed distribution of the clay minerals indicates that 

the dominant current in the Bering shelf is the northflowing Alaska Coastal Water. This current distributes 

fine-grained sediment northward from the Kuskokwim 

River into the Chirikov Basin, primarily around the 

western end of St. Lawrence Island and into Norton 

Sound, where the sediment is mostly masked by the 

Yukon River clay-mineral suite. Yukon detritus moves 

primarily to the northwest and enters the Chukchi Sea 

through the Bering Strait, but some sediment moves 

around Norton Sound in a sluggish counterclockwise gyre. 

Sediment-dispersal routes suggest that pollution in 

Norton Sound, such as an oil spill, could result in the 

rapid distribution of pollutants throughout the northern 

Bering Sea area. Because Norton Sound is shallow, 

resuspension of bottom sediments by tidal fluctuations 

and storm waves also could cause rapid distribution of 

pollutants. 

INTRODUCTION 

Analysis of clay minerals in bottom and suspended 

sediments from the Yukon and Kuskokwim Rivers and 

from the northern Bering Sea shelf off Alaska allowed 

determination of fine-grained sediment sources, 

sediment-dispersal routes, and inferred current 

patterns. Because of pending offshore oil development on 

the northern Bering shelf, this kind of information is 

invaluable for determining the possible dispersal routes of 

oil spills and the siting of offshore drilling platforms and 

pipelines. 

ACKNOWLEDGMENTS 

Many thanks to colleagues C. H. Nelson, D. A. 

Cacchione, and D. E. Drake for providing sediment 

samples. D. E. Drake and H. A. Karl offered helpful 

advice in their reviews of this manuscript. Discussions 

·with C. H. Nelson and D. E. Drake were enlightening. 

Technical assistance was provided by Mary Ann Allan, 

Eva Vanek, and Phyllis A. Swenson. 

REGIONAL SETTING 

The area studied includes Norton Sound, Chirikov 

Basin, and the epicontinental shelf area of the Northern 

Bering Sea (fig. 1). We also studied samples from the 

area north of St. Lawrence Island and the southernmost 

part of the Bering Strait. 

Bathymetry 

The shelf area from the Yukon delta to the Bering 

Strait is relatively flat and shallow. The bottom 

topography (fig. 2) suggests that the Yukon River crossed 

the shelf and flowed into the Chukchi Sea prior to the 

Holocene transgression (McManus and others, 197 4). 

Chirikov Basin displays a more complex, uneven 

topography, probably caused by Pleistocene glaciation 

(Moll, 1970). Between the Yukon delta and St. Lawrence 

Island are two linear depressions with an intervening 

ridge; all trend north-south (Kn~bel and Creager, 1973a, 

b). The topography in Norton Sound is smooth, with a 

gradual increase in depth from east to west and few 

depressions where sediment may be trapped. 

Major Currents 

A major north-trending current (water mass) is 

present off the western Alaska coast. This current is 

called the Alaska Coastal Water (ACW) where it borders 

the coast (Goodman and others, 1942; Coachman and 

Aagaard, 1966; Sharma and others, 1974; Nelson and 

others, 1975; Drake and others, 1980). The current moves 

northerly, parallel to the Alaskan coastline, swinging into 

the Bering Sea at the Yukon delta and then through the 

Bering Strait into the Chukchi Sea. At the Yukon delta 

the ACW bifurcates, with a sluggish branch moving into 

Norton Sound (Coachman and Aagaard, 1966). The ACW 

is normally present westward to a depth of 30 m (greater 

through the Bering Strait). Velocities range from 10 

(bottom) to 20 (surface) cm/s in the seaward areas but 

increase to velocities of 30 to 40 cm/s within 30 km of 

the shoreline (Husby, 1969, 1971; McManus and Smyth, 

1970; Fleming and Heggarty, 1976; see Drake and others, 

1980 for a detailed discussion of currents and their 

velocities). In the Bering Strait, where the ACW is 

1 
funneled into the Chukchi Sea, velocities reach a 

maximum of 180 cm/s. 

A distinct counterclockwise gyre in Norton Sound is 

a manifestation of the sluggish branch of the ACW (fig. 

2). After this gyre moves along the margin of Norton 

Sound, it rejoins the main branch of the ACW south of 

Port Clarence. The gyre is created in part by the 

interaction of the ACW with discharge from the Yukon 

River (Nelson and Creager, 1977; Drake and others, 1979, 

1980). 

Another northward-moving current flows from the 

Pribilof Islands to St. Lawrence Island through the 

western part of the study area. Just south of St. 

Lawrence Island the current bifurcates and joins the ACW 

to the east. The western arm flow is less clearly defined 

and may move northward through Anadyr Strait into the 

northern Bering Sea or southward (Knebel and Creager, 

1973a, b; fig. 2). 

Major Sources and Dispersal of Sediments 

Two major fluvial systems contribute sediment to 

the study area-the Kuskokwim River to the southern 

Bering Sea and the Yukon River to southwestern Norton 

Sound (fig. 2). The Kuskokwim River does not flow in the 

winter because it freezes, but the Yukon maintains a 

small winter flow (Drake and others, 1979). Major 

discharge of sediment takes place in the summer months 

U.S.S.R. 

Pribilof 

•Ill> Islands 

of June to October- (Lisitsyn, 1966; Drake and others, 

1980). Local streams tfong northern Norton Sound 

provide about 2 to 3x10 metric tons of sediment per 

year (Drake and others, 1980). 

The Ygkon River contributes annually between 40 

and lOOxlO metric tons of suspended and bedload 

sediment to the Bering Sea (Lisitsyn, 1966; Drake and 

others, 1980). The Yukon ranks 18th among the world's 

rivers in total annual sedisnen~ discharge, having a 

drainage area of about 8.5xl0 km (Lisitsyn, 1966; Inman 

and Nordstrom, 1971). Ninety percent of the river-borne 

sediment in the Bering Sea comes from the Yukon 

(Lisitsyn, 1966). 

The Kuskokwim River also discharges sediment to 

the shelf. This sediment is transported northwest toward 

St. Lawrence Island and along the Alaskan coast by the 

ACW. The suspended-sediment concentration, 

determined from midchannel flow, ranges in the summer 

months from 100 to 200 mg/L (Carlson and others, 

1975). The contribution of sediment to the shelf is 

considerably less than that from the Yukon River 

(Lisitsyn, 1966). 

Sediment in Norton Sound is additionally distributed 

by resuspension due to storm activity and tidal 

fluctuations (Nelson and Creager, 1977; Drake and others, 

1979, 1980; Cacchione and Drake, 1982). Shore-fast ice 

occurs in the winter in Norton Sound; the effects of ice 

rafting on sediment transportation and deposition are 

poorly known (Dupre, 1978). 

Canada 

Gulf of Alaska 

0 200 400 600 KILOMETERS 

Figure 1. Location of study area (shaded) in the northern Bering Sea. Map from Howard and Nelson (1982.} •. 

2 
Geology 

Nor ton Sound is flanked on the north by the Seward 

Peninsula and on the east and south by the YukonKoyukuk province, which extends from the Brooks Range 

in the north to the Yukon delta. South of the delta the 

CHUKCHI SEA 

~ (/ 

/ ./ 

U.S.S.R. 

Yukon-Koyukuk province is bordered by the YukonKuskokwim coastal lowland. Patton (1971) described the 

Yukon-Koyukuk province as a vast tract of Cretaceous 

rocks locally veneered by Quaternary alluvial deposits 

and volcanic rocks. The Cretaceous sequence consists of 

marine andesitic volcanic rocks, graywacke, mudstone, 

PENINSULA 

EXPLANATION 

___ .-. Water circulation 

~:~ 100 50 t Maximum bottomO cunent velocities 

cmjs 

...-- 10 __..- Depth in meters 

e16 Sample locality 

Chukotka SEWARD 

I 

I 

A 

I 

/ 

f 

/ 

f 

,. ~ 

'~ --..... \ I 

( } 

.....,_ ..... / 

I \. 

I \ 

/ \ 

PENINSULA 

N 

\ 

1 50 KILOMETERS 

Figure 2. Northeastern Bering Sea and southern Chukchi Sea, showing water circulation, distribution of 

Alaska Coastal Water (arrows), measured bottom-current velocities, and bathymetry. NBSS is northern 

Bering Sea shallows. Figure from Nelson ( 198 2). 

3 
and shallow marine to nonmarine beds. Cenozoic rocks 

are felsic volcanic rocks with underlying basalts. 

The Seward Peninsula is predominately Precambrian 

sedimentary rocks and metamorphosed rocks; the latter 

include quartz schist, phyllite, argillite, dolomitic 

limestone, gneiss, and slate. Less extensive outcrops of 

Paleozoic marble, dolomite, and chert underlie Mesozoic 

felsic intrusive rocks. 

METHODS 

Both bottom and suspended sediment from Norton 

Sound and the adjacent shelf were collected during the 

summer (ice-free) months of 1968-70 and 1976-77. A 

total of 615 bottom and suspended samples were 

collected, of which 53 bottom samples and 54 suspendedsediment samples were used in this study. . The 

distribution of offshore suspended-sediment samples is 

different from that for bottom-sediment samples (figs. 3, 

6). In the summers of 1972 and 1975, 12 samples from 

bank and suspended sediment were collected in the Yukon 

and Kuskokwim Rivers. 

Box cores were taken at each offshore bottom 

station. From the surface of the core an approximately 

5- to 10-g sample of sediment was taken for clay-mineral 

analysis. 

Suspended-sediment samples were collected in 

Nor ton Sound, in the northern Bering Sea shallows, 

northeast of the Bering Strait, and west of Port Clarence; 

suspended-sediment samples were not available from 

Chirikov Basin and north of St. Lawrence Island. Water 

samples of 1 L were collected in Van Dorn bottles. 

Samples were collected at various depths in the water 

column at each station. In Norton Sound, water was 

collected at 2- to 4- m intervals; in the outer shelf, 

where water depths are greater, the sampling interval 

ranged from 10 to 15 m through the water column. Each 

1-L sample was passed through a Millipore filter with 

pore diameters of 0.4 m. The amount of suspended 

material collected on the filter paper usually weighed 

less than 6 mg, with a few ranging from 10 to 20 mg. 

X-ray techniques used for clay mineralogy were 

described by Hein and others (1976). Sediment was 

treated to remove organic matter and Caco3, 

0 

I 

.39 

e35 

50 KILOMETERS 

I I 

Figure 3. Distribution of chlorite+kaolinite in bottom sediment. Values are in percentage of 

chlorite+kaolinite in the clay-mineral suite and are contoured at a 5-percent interval. Arrow just north of 

western St. Lawrence Island indicates sample location is immediately west of the edge of the map. Contour 

lines dashed where approximately located. 

4 
respectively, using 30 percent hydrogen peroxide and 

Morgan's solution (sodium acetate plus glacial acetic acid 

diluted with distilled water). The samples were then 

washed repeatedly with additional Morgan's solution and 

centrifuged to isolate the 2- m size fraction. The 2- m 

fraction was saturated with MgC12 and X-rayed, then 

treated with ethelene glycol and X-rayed again. Peak 

areas rather than peak heights were measured, and the 

relative clay percentages were calculated from the 

weighted peak areas and were summed to equal 100. 

Biscaye's (1965) weighting factors were used: two, four, 

and one times the peak areas of kaolinite plus chlorite, 

illite, and smectite, respectively. Because kaolinite 

makes up a small fraction of the clay-mineral assemblage 

in the area studied and it is difficult to determine its 

relative abundance accurately when present in small 

amounts, the chlorite+kaolinite abundances were 

considered together. In this paper smectite is used as a 

general term to represent any mineral phases that expand 

to about 17 A when glycolated. The expandable minerals 

are most commonly smectite-group minerals but may also 

include degraded chlorite and illite or some mixed-layer 

clays (Naidu and others, 1982). 

The techniques used to determine the clay 

mineralogy of the offshore bottom samples differ from 

the technique used for the offshore suspended-sediment 

samples. The small amounts of sediment trapped on the 

filters made it impossible to put the samples through the 

same chemical treatments and size segregations used for 

the bottom samples. Instead, the sediment-coated filter 

papers were washed with distilled water to remove the 

salts and the loose coarse-grained particles. The filter 

paper and sediment was then saturated with MgC12 for 

one-half hour and rinsed twice with distilled water. A 

section of filter paper was cut out, placed on a glass 

slide, and allowed to dry in a dessicator before being 

glycolated. X-ray diffractograms were taken of each 

sample as described above; reproducibility within a single 

sample of suspended sediment was always within seven 

percentage points. The results from the suspended 

sediment are presented in three ways: (1) the averages 

of the suspended sediment collected at all depths in the 

water column at a specific station (figs. 6-8), (2) the 

value of the suspended-sediment sample nearest the 

surface (figs. 9-11), and (3) the value of the suspendedsediment sample from nearest the sea floor (figs. 12-14). 

Suspended-sediment samples from the Yukon and 

Kuskokwim Rivers were collected in liter bottles. All 

sediment was recovered by centrifugation; samples were 

not passed through Millipore filters. River suspended and 

bottom sediments were analyzed for clay mineralogy in 

the same way as offshore bottom samples. 

Several drawbacks are inherent in the technique 

used for the analysis of the small amounts of offshore 

suspended sediment collected: (1) The analysis of 

offshore bottom sediments and all river sediments was of 

clay-sized debris only, whereas the offshore suspendedsediment samples were of varying and unknown size 

fractions, thus making the validity of any comparisons 

uncertain; however, from examinations of the sedimentladen filter paper under a stereoscopic microscope, it 

appears that the suspended sediment is mostly fine 

grained; (2) nonclay minerals present in the suspendedsediment samples decrease the quality of the 

diffractograms; (3) muscovite cannot be separated from 

illite by this technique, which causes anomalously high 

illite concentrations for some suspended sediments; (4) 

some clays ( 0.4 m), especially smectite, may have 

passed through the Millipore filter, although, certainly 

not all of the smectite would have passed through. Gibbs 

(1967, 1977) stated that smectite was the finest grained 

clay in the Amazon clay-mineral suite, with an average 

size of 0.4 m and a range of 0.9 to 0.1 m. However, 

Gibbs' results could also be interpreted as a density 

effect due to settling technique, inasmuch as smectite is 

the least dense of the clay minerals. Regardless, the 

possibility exists that some smectite was lost through the 

technique used to recover the offshore suspended 

sediments; river suspended sediments, however, were not 

passed through a filter. 

DISTRIBUTION OF SEDIMENT 

Bottom Sediment 

On the basis of the distribution of clay minerals, 

the study area is divided into three parts (fig. 2): (1) 

Chirikov Basin, the western and central part of the 

northern Bering Sea, (2) Norton Sound, and (3) the 

northern Bering Sea shallows, defined by Moll (1970) as 

the narrow north-south strip of sea floor between Norton 

Sound and Chirikov Basin. 

Norton Sound 

Chlorite + kaolinite values (fig. 3) show the least 

amount of variation, with values mostly in the range of 

35 to 40 percent. Chlorite+kaolinite is highest (40 to 45 

percent) close to the Yukon delta and decreases to the 

east (35 to 40 percent) and north (35 to 40 percent) to as 

far as the central part of the sound, where it again 

increases toward the northern shore (40 to 50 percent). 

The distribution of illite (fig. 4) is similar to that of 

chlorite+kaolinite, with percentages near the Yukon delta 

ranging from 45 to 50 percent with concentrations 

decreasing slightly from 40 to 45 percent in the eastcentral parts of the sound. Adjacent to the northern 

Norton Sound coastline, illite is less abundant (30 to 40 

percent) than chlorite+kaolinite. Smectite (fig. 5) is 

distributed in a distinct halo around the Yukon delta area, 

with concentrations increasing to the north and east (15 

to 25 percent). Lower percentages (0 to 10 percent) 

occur adjacent to the northern and southern coasts. 

Northern Bering Sea Shallows and Chirikov Basin 

Each clay mineral delineates concentration 

gradients trending northwest-southeast across the 

northern Bering Sea shallows that extend from just east 

of St. Lawrence Island to the Bering Strait (figs. 3-5). 

The gradients are generally less steep to the south but 

become very steep to the north, as they converge on the 

narrow Bering Strait. Both illite and chlorite+kaolinite 

are less concentrated at the center, flanked by increasing 

concentrations to both the east and west. illite values 

are greatest to the northwest of St. Lawrence Island (55 

percent), with a gradual decrease eastward to the center 

of the shallows (fig. 4). A reversal in the gradient of 

chlorite+kaolinite occurs to the northwest of St. 

Lawrence Island, where it decreases to 30 to 40 percent 

(fig. 3). The greatest concentration of smectite occurs 

midchannel in the shallows (fig. 5). Smectite decreases 

5 
rapidly to the east and west of the channel. A deviation 

from this smooth-trending decrease of smectite is a 

slight increase of 5 percent just north of central St.-

Lawrence Island. 

In summary, for bottom-sediment samples, high 

illite percentages generally dominate in both Norton 

Sound and the eastern section of the northern Bering 

shelf. It is only near the Bering Strait that 

chlorite+kaolinite dominates the clay-mineral suite, 

whereas smectite is dominant only in a few samples from 

the center of the northern Bering Sea shallows. 

Suspended Sediment 

The distribution of chlorite+kaolinite in the nearsea-floor suspended sediment, the near-sea-surface 

suspended sediment, and the average values through the 

water column at each station are similar, as might be 

expected (figs. 6, 9, 12). Chlorite+kaolinite values in the 

near-bottom suspended sediment (fig. 13) show a smooth 

gradient from low concentrations in northern Norton 

Sound to high concentrations in the south-central part of 

the sound; the trend then reverses and concentrations 

decrease to the south. Thus, chlorite+kaolinite values in 

the near-bottom suspended sediment define northwestsoutheast-trending belts of similar concentrations that 

\ 

\ 

roughly parallel the northern coast, with the belt of 

highest concentration between belts of decreasing 

abundance on either side. The pattern for 

chlorite+kaolinite in near-surface suspended sediment 

(fig. 9) is more complex; it has two areas of high 

concentration-one trending northwest from the Yukon 

delta marking the western limit of the data points, and 

one in the south-central part of Norton Sound. In the 

northern part of the study area the reversing 

concentration gradients seen for the near-bottom 

sediment values are also seen for the near-surface 

suspended-sediment values. Because more data are 

available for the average chlorite+kaolinite values from 

the entire water column at each station, more detail in 

distributions can be determined (fig. 6); however, the 

overall pattern is the same as described above. 

Illite distribution (figs. 7, 10, 13) generally follows 

the same pattern of northwest-southeast belts of nearly 

equal concentrations as that shown by 

chlorite+kaolinite. Two differences are evident, 

however, for both the near-surface and near-bottom 

suspended-sediment distributions: (1) they show steeper 

gradients across central Norton Sound, and (2) they show 

values that are lowest in the center, with belts of 

increasing concentration on either side. Illite abundance 

ranges from 50 to 70 percent. The concentrations just 

I 

\ 

.43 

50 KILOMETERS 

I I 

Figure 4. Distribution of illite in bottom sediment. Values are in percentage of illite in the clay-mineral 

suite and are contoured at a 5-percent interval. Symbols same as for figure 3. 

6 
south of the Bering Strait for near-bottom and nearsurface suspended sediment range from 50 ·to 60 percent, 

showing less variation than suspended sediment farther to 

the south, in Norton Sound. 

Smectite is present in only a few suspendedsediment samples (figs. 8, 11, 14). Areas that show 

smectite are over the Yukon prodelta and in a small belt 

along the north-central coast of Norton Sound (fig. 8). 

Smectite is minor in the Port Clarence-southern Bering 

Strait areas. 

Overall the suspended-sediment clay-mineral suite 

is illite dominated, with chlorite+kaolinite slightly less 

both in Norton Sound and the Bering Strait. In nearsurface suspended sediment both illite and 

chlorite+kaolinite increase from the Yukon prodelta 

seaward. However, in near-bottom suspended sediment 

illite and chlorite+kaolinite values differ in that illite 

percentages are high over the prodelta and in the 

northern sound (range 50 to 70 percent) (fig. 13), whereas 

chlorite+kaolinite percentages show minor change over 

the prodelta to the middle of Norton Sound (range 35-45 

percent) (fig. 12). · 

Yukon River 

The average clay-mineral percentages of the Yukon 

River bank sediment are 45, 51, and 4 percent for 

chlorite+kaolinite, illite, and smectite, respectively. The 

excellent diffractograms of the suspended sediment show 

averages of 50 percent chlorite+kaolinite, 50 percent 

illite, and no smectite (table 1). The concentration of 

illite in bank and river sediment is higher than that for 

most of the offshore study area exclusive of the 

midchannel of the northern Bering Sea shallows and the 

areas bordering the Yukon delta. The average 

chlorite+kaolinite value from the Yukon system is slightly 

higher (5 to 15 percent most commonly) than that for 

many offshore samples but, as might be expected, 

matches most closely the near-surface suspendedsediment data. Smectite shows markedly lower 

concentration in the Yukon system than in most offshore 

bottom deposits, but it also more closely matches 

offshore suspended sediment in concentration. Naidu and 

others (1982) reported that the Yukon River bottom 

sediment contains a 21 percent expandable phase 

(smectite as used here), but they do not clearly state the 

location or the time of year their six Yukon River 

samples were collected, so it is difficult to evaluate the 

possibilities for the difference in their 21 versus our 4 

percent for bank and 0 percent for suspended sediment. 

In addition, Naidu and others (1982) measured 41 percent 

illite and 38 percent chlorite+kaolinite for the Yukon 

bottom sediment. 

0 50 KILOMETERS 

I I I 

Figure 5. Distribution of smectite in bottom sediment. Values are in percentage of smectite in the claymineral suite and are contoured at a 5-percent interval. Symbols same as for figure 3. 

7 
Kuskokwim River 

The Kuskokwim River averages 53 and 50 percent 

illite for the bottom and suspended sediment, 

respectively (table 1); thus, slightly more illite is found in 

the river than in suspended and bottom sediment in 

Norton Sound and the western Bering shelf. However, 

similar illite concentrations occur in bottom sediment 

from the eastern Bering Sea-Chirikov Basin area. 

Chlorite+kaolinite values in the Kuskokwim River bottom 

(47 percent) and suspended-sediment samples (50 percent) 

are higher than for most of the bottom sediment in the 

offshore study area (table 2). A similarly chlorite-rich 

suite is found, however, along the Norton Sound coast and 

just south of the Bering Strait. 

Less than 1 percent smectite is present in bottom 

and suspended sediment from the Kuskokwim River, a 

dramatically lower concentration than in Norton Sound 

and Bering shelf bottom sediments (table 2). Low 

smectite concentrations (0 to 10 percent) in offshore 

bottom deposits are found only near the Yukon delta and 

in the northwestern Bering Sea. The suspended-sediment 

clay-mineral suite from the Kuskokwim River correlates 

well with the suite in Norton Sound and the southern 

Bering Sea. Naidu and others (1982) measured 60 percent 

\ 

\ 

illite, 40 percent chlorite+kaolinite, and trace smectite 

for the clay mineralogy of the Kuskokwim River, results 

comparable to ours. 

SEDIMENT SOURCES AND DISPERSAL ROUTES 

Biscaye (1965) and Hein and others (1976, 1979) are 

among several workers who have shown that source areas 

and sediment-dispersal routes can be determined by the 

study of clay mineralogy. From delineation of sedimentdispersal routes, oceanic current patterns can be inferred 

(Hein and others, 1979). In this study, the Kuskokwim and 

Yukon Rivers are the major fluvial sources that 

contribute clay minerals to the area under 

consideration. Analysis of the river clay-mineral suites 

enables evaluation of the rivers as potential sources for 

offshore clay-mineral suites. From this evaluation, 

possible transportation routes can be determined. 

Examination of offshore suspended and offshore 

bottom sediment allows a three-dimensional view of 

sediment dispersal. Correlation of suspended sediment 

with bottom sediment in this study, however, is restricted 

by the considerations discussed in the methods section. A 

further consideration is that bottom-sediment samples 

represent an average of several hundred years of 

0 50 KILOMETERS 

I I I 

Figure 6. Distribution of chlorite+ kaolinite in the day-mineral suite in suspended sediment. Values are the 

average percentage of chlorite+kaolinite for all depths in the water column and are contoured at a 5-percent 

interval; contours dashed where approximately located. 

8 
sedimentation in contrast to offshore and river suspended 

sediments, which represent only daily or weekly sediment 

averages. Thus, the two data sets must be compared with 

these facts in mind. 

Bottom Sediment 

The Yukon River is unquestionably a primary source 

of Holocene sediment for Norton Sound and the 

northwestern Bering Sea (Moll, 1970; Carlson and others, 

1975; fig. 15). The thickness of Holocene sediment 

decreases away from the Yukon River mouth (fig. 15). To 

the south, the Kuskokwim River also supplies significant 

amounts of sediment to the west-central Alaskan coast; 

from here the sediment is distributed north by currents 

(Knebel and Creager, 1973). The Yukon plume diverges 

from the southwest main distributary transporting finegrained sediment to the north and also eastward along the 

coast of Norton Sound (Carlson and others, 1975). There 

is also minor southward flow from the Yukon delta 

(Carlson and others, 1975; Drake and others, 1980). A 

thick accumulation of Yukon-derived Holocene sand 

occurs along the margins of southern and south-central 

Norton Sound, composing the Yukon prodelta. Evidence 

for a northwestward-moving plume is supported by the 

\ 

\ 

patterns of the fine-grained bottom deposits as 

determined in this paper. All three clay minerals 

indicate a northwestward distribution trend from the 

delta, as well as possible distribution by a 

counterclockwise gyre in central Norton Sound. As would 

be expected, the distinct plume-shaped distribution of 

clay-mineral concentrations away from the Yukon River 

indicates the presence of a clay-mineral suite 

immediately offshore similar to that found in the Yukon 

River. The slight decrease (5 percent) in the 

concentrations of chlorite+kaolinite and illite directly 

northwest from the delta suggests rapid current removal 

of fine-grained sediment, an influx of clay minerals from 

another source that mixes with the Yukon clay-mineral 

suite, or a different clay-mineral suite being delivered by 

the Yukon during the year the offshore suspended 

sediment was collected. Yukon suspended sediment may 

in part be "stored" in Norton Sound prior to movement 

along the north coast and then farther north into the 

Bering Strait (see also Drake and others, 1979). This 

temporary holding period in the sound would allow time 

for some fine-grained sedimentation to occur (Moll, 

1970). Both chlorite+kaolinite and illite abundances can 

be mapped in broad bands to the northeast of the Yukon 

delta, which may indicate that these minerals are widely 

0 50 KilOMETERS 

I I I 

Figure. 7. Distribution of illite in the clay-mineral suite in suspended sediment. Values are the average 

percentage of illite for all depths in the water column and are contoured at a 5-percent interval; contours 

dashed where approximately located. 

9 
dispersed in Norton Sound by settling from the sluggish 

counterclockwise gyre. Clay minerals that form a belt 

parallel to the northern coast of Norton Sound are 

probably derived locally from coastal erosion and runoff 

from small coastal streams; however, clays in the· 

northern sound might be a mixture of locally derived clay 

minerals and Yukon clay minerals brought around in the 

counterclockwise gyre. Nelson and Creager (1977) 

showed that relict sands occur in the northern Bering Sea 

shallows and that very little clay-sized debris is present. 

Yet, this small amount of clay minerals is probably not 

relict but contemporary-a condition similar to that 

found in Cook Inlet, Alaska (Rein and others, 1979). 

Bottom sediment in Chirikov Basin is similar to that 

of the northern Bering Sea shallows in that it is primarily 

relict sand, mostly glacial debris (Moll, 1970). 

Chlorite+kaolinite and illite abundances in Chirikov Basin 

are similar to their abundances in the Yukon and 

Kuskokwim Rivers. Perhaps the Kuskokwim River is a 

likely source for Chirikov Basin illite and 

chlorite+kaolinite, which were transported north and 

around the western end of St. Lawrence Island. This 

possibility supports Knebel and Creager's (1973a) 

suggestion that currents carrying Kuskokwim-derived 

sediment flow northwest through Anadyr Strait. 

Additional support for the Kuskokwim input is seen in the 

smectite distribution. Both the Kuskokwim and Yukon 

samples we analyzed have little smectite. Similarly low 

smectite values occur only in the western Chirikov Basin 

and in the Yukon plume, although the Yukon may have 

Table 1. Clay-mineral percentages in sediment from the Yukon and Kuskokwim 

10 

Rivers as determined by X-ray diffraction. 

[See fig. 2 for location of sample~. Suspended samples collected June 20, 

1975; water discharge was 17,641 m Is] 

Sample Chlorite Kaolinite Chlorite+Kaolinite Illite Smectite 

YUKON RIVER BANK SEDIMENT 

Y-1-------- 33 8 41 50 9 

Y-2-------- 34 13 47 51 3 

Y-3B------- 32 16 48 51 1 

YUKON RIVER SUSPENDED SEDIMENT 

Y-3-14----- 36 14 51 49 1 

Y-3-18----- 40 11 50 50 0 

Y-3-21----- 37 13 50 50 0 

Y-3-24----- 39 13 52 48 0 

Y-3-27----- 36 13 49 51 0 

KUSKOKWIM RIVER BOTTOM SEDIMENT 

16--------- 36 7 43 56 1 

613-------- 45 12 57 43 0 

637-------- 30 11 40 60 <1 

KUSKOKWIM RIVER SUSPENDED SEDIMENT 

319-------- 42 8 50 50 0 

Y-1 is mud exposed in bank 2 mi (3.2 km) from coast along Kwigaki Pass. 

Y-2 is silt/mud near junction of Kwikpak and Kawanak passes. 

Y-3B is bank sample at Pilot Station. 

Y-3 is at Pilot Station, lat 61°56'04" N. and long 162°52'50" W.: 14 is near 

left bank, 18 is between midchannel and left bank, 21 is midchannel, 24 is 

between midchannel and right bank, 27 is near right bank. Each value (14, 18, 

21, 24, 27) is an average of the lower half and upper half of the water column; 

each station had essentially the same mineralogy. 
greater amounts of smectite at different times of the 

year (see following paragraph). In contrast to these data, 

Moll's (1970) sparse data show a decrease in illite toward 

the east and in Chirikov Basin, which is opposite to the 

trend we observe. 

One of the most significant aspects of this study is 

the remarkably high concentrations of smectite in marine 

bottom deposits as compared to the rivers. The greatest 

concentration occurs in the northern Bering Sea shallows 

following the northwest-southeast trend apparently 

established by the Alaska Coastal Water. Four 

explanations are possible for this discrepancy between 

marine and river compositions: (1) A smectite-rich suite 

may be derived from sediment adjacent to the Aleutian 

Island arc and brought north by the major current 

systems. Smectite-rich clay-mineral suites are known to 

occur in sediment adjacent to the Aleutian Ridge (Hein 

and others, 1976). Smectite could be further 

concentrated relative to illite and chlorite in the northflowing currents by segregation according to varying size 

or density, as occurs off the Amazon River mouth (Gibbs, 

1967, 1977). (2) Erosion of volcaniclastic and volcanic 

rocks on Chukotka Peninsula and adjacent areas in Siberia 

could produce smectite-rich clays that are brought 

eastward by currents. Current patterns may have been 

different during glacial periods than now, with increasing 

sediment contributions from areas different from those· 

that dominate today. (3) Erosion of local bedrock 

outcrops on the northern Bering Sea shelf may provide 

smectite-rich clays. High concentrations of smectite on 

the Gulf of Alaska shelf are direetly correlative with 

bedrock exposures of the shelf itself (Molnia and Hein, 

1982); however, very few bedrock outcrops exist on the 

northern Bering Sea shelf. (4) The clay-mineral 

composition of the Yukon River may change from year to 

year or from season to season. Although changes in the 

mineralogy of major rivers like the Yukon have not been 

reported, such a change is supported by the different 

clay-mineral suites obtained in this study compared to 

those obtained by Naidu and others (1982). These 

differences in composition are greater than can be 

explained by analytical errors or differences in 

techniques of clay-mineral analysis. In contrast, the 

clay-mineral suites determined for the Kuskokwim River 

irithis study and for Naidu and others' study are similar, 

suggesting a greater constancy in the composition of the 

Kuskokwim. Combinations of suggestions l, 2, and 4 may 

explain the greater amount of smectite in bottom 

sediments versus the rivers. 

In summary, smectite concentrations in Norton 

Sound are considerably higher (10 to 25 percent) than 

concentrations for the Yukon (2 percent) or Kuskokwim 

(less than 1 percent) Rivers and also much higher in 

places than measured for the Yukon (21 percent) by Naidu 

and others (1982). Interestingly, the concentration 

percentages of the the clay-mineral suite that Naidu and 

others (1982) determined for their Yukon River sediment 

are identical to the average values we obtained for all 

our offshore bottom sediments, whereas the average 

values for all the offshore suspended-sediment samples 

are the same as those determined for the clay-mineral 

suite of the Kuskokwim River. It is not known which 

conditions control the clay-mineral composition of the 

Yukon River. Clearly, the times at which and places 

where the Yukon was sampled by Naidu and others (1982) 

are more typical of what the river has delivered to the 

shelf than are the samples we analyzed, which were 

collected on June 20, 1975, at Pilot Station, about 60 km 

from the river ~outh. The flow rate during our sampling 

was 17,641 m /s, only &Jightly less than the maximum 

fiow of nearly 20,000 m /s that most commonly occurs 

after ice breakup in late May or early June (Drake and 

others, 1980). Perhaps much of the clay-sized material 

was flushed out of the system during onset of the spring 

thaw. Summer suspended-sediment samples from the 

Yukon contain less than 10 percent clay-sized material 

(Drake and others, 1980). The higher smectite 

concentration in Norton Sound versus values we obtained 

-for the Yukon River is probably due to seasonal variations 

in the composition of the Yukon and to transport of 

smectite by the north-flowing ACW or by current now 

from eastern Siberia during glacial periods. 

Suspended Sediment 

The distribution of suspended sediment is delineated 

by a northwesterly trend in the clay-mineral 

concentrations from the Yukon delta to the Bering Strait 

Table 2. Average and range of clay mineral percentages of bottom- and 

suspended-sediment samples from Norton Sound and adjacent Bering shelf. 

Chlorite Kaolinite Ch1orite+Kaolinite Illite Smectite 

BOTTOM SEDU1ENT 

Average---- 28 10 38 42 21 

Range------ 18-36 0-17 22-52 23-53 0-48 

SUSPENDED SEDIMENT 

Average---- 33 9 42 57 <1 

Range------ 15-54 1-19 21-59 41-79 0-4 

11 
(figs. 6-14). The clay-mineral suite adjacent to the 

Yukon River is very similar to that of the Yukon River 

itself (figs. 6-8). Kuskokwim-type clay-mineral suites 

may be traceable into the northern Bering Sea shallows, 

suggesting transportation from the south in a current that 

diverges slightly around the Yukon delta in its 

northwesterly movement. The illite-rich suite along the 

northern coast of Norton Sound may be derived partly 

from the gyre in Norton Sound which carries sediment 

from the Kuskokwim or from farther south (figs. 6, 7) and 

partly from clays supplied locally as described for the 

bottom sediments. Both Kuskokwim- and Yukon-like clay 

suites are discernable at the southern entrance of the 

Bering Strait. If these suites are in fact from the two 

rivers, then both rivers supply sediment that is funneled 

directly into the Chukchi Sea through the Bering Strait 

(see also Naidu and others, 1982). 

Near-surface suspended-sediment values are nearly 

the same as the average values for suspended sediment in 

the water column (figs. 9, 10). However, as described 

previously, clay-mineral-concentration gradients of the 

near-surface suspended sediment are slightly steeper than 

gradients of the near-bottom suspended-sediment 

concentrations (figs. 12, 13). The near-bottom claymineral suites show a more uniform gradient, which may 

\ 

indicate less m1xmg from different sources for bottom 

deposits (Figs. 12, 13). Although the concentration of 

smectite in the water column during the summer months 

does not help explain the enigmatic concentrations in 

bottom sediment, it is an excellent indicator of shortterm summer sources. The percentage of smectite in 

bottom sediment in the Kuskokwim River (ll percent) 

supports the interpretation that it is a source of finegrained sediment in Norton Sound and the Bering Strait. 

Since the Yukon can apparently have varying amounts of 

smectite in the suspended sediment and minor smectite in 

bank samples, the minor smectite in suspended sediment 

over the Yukon prodelta is probably derived from the 

river and from resuspension of bottom material by storm 

waves or tidal fluctuations. Smectite also seems to be a 

good indicator of movement along the north shore of 

Norton Sound. Percentages here range from 3 to 4 in 

near-bottom sediment, also suggesting resuspension of 

bottom deposits. 

In summary, assuming that the smectite contents of 

the offshore suspended-sediment samples are not an 

anomaly of the filtration process, the Kuskokwim 

sediment is apparently represented in many areas of the 

Norton Sound and the adjacent shelf. In contrast, the 

Yukon clay-mineral suite is most clearly identified in 

0 50 KILOMETERS 

I 1 I 

Figure 8. Distribution of smectite in the clay-mineral suite in suspended sediment. Values are the average 

percentage of smectite for all depths in the water column and are contoured at a 5-percent interval; contours 

dashed where approximately located. 

12 
suspended sediment that occupies a narrow band that 

stretches from the river mouth to the Bering Strait. 

Inferred Current Patterns 

On the basis of the bottom- and suspended-sediment 

data and previous studies, several distinct current 

patterns are indicated: (1) The Alaska Coastal Water 

(ACW) coming from the south and diverging at the Yukon 

delta northwest toward the Bering Strait and east into 

Norton Sound-this current also bifurcates and moves 

around the west side of St. Lawrence Island; (2) a 

counterclockwise gyre in central Norton Sound; and (3) a 

current moving along the north shoreline of Norton 

Sound, either influenced to some degree by movement of 

the ACW or wholly by local tidal action stimulating 

longshore drift. 

The ACW, the major distributor of sediment, 

transports Kuskokwim as well as Yukon sediment. Yukon 

sediment is dispersed in two directions-a predominant 

flow to the northwest, indica ted by steep gradients in the 

contoured clay-mineral data (figs. 6-8), and a more 

diffuse flow of fine-grained sediment eastward into most 

of Norton Sound. The clay mineralogy also indicates 

movement along the north shore of the sound. The 

\ 

\ 

existence of both the ACW and the slower current in 

Norton Sound is also supported by temperature and 

salinity studies (Carlson and others, 1975; Nelson and 

Creager, 1977). 

Clay suites in Chirikov Basin and the westernmost 

part of the northern Bering Sea shelf suggest current 

transport from the south around the western end of St. 

Lawrence Island through Anadyr Strait. This current 

merges with the ACW just south of the Bering Strait. 

Clearly, currents from both Norton Sound and Chirikov 

Basin converge with the main branch of ACW in the 

northern part of the Bering shelf before passing through 

the Bering Strait. 

ENVIRONMENTAL CONSIDERATIONS 

Oil spilled within the rapidly northward moving 

ACW is likely to be transported northward and into the 

Chukchi Sea, as is the fine-grained sediment. 

Consequently, although spills could be removed from 

Norton Sound, an important fishing area, they could still 

be widely distributed to the north. It is unclear how 

much oil would be carried eastward past the ACW into 

Norton Sound and dispersed by the counterclockwise gyre 

and the longshore drift that occurs off the northern 

0 50 KILOMETERS 

I I I 

Figure 9. Distribution of chlorite+kaolinite in near-surface suspended sediment. Values are the percentage of 

chlorite+kaolinite in the clay-mineral suite and are contoured at a 5-percent interval; contours dashed where 

approximately located. 

13 
coast. Potentially a spill could have a devastating effect 

on the coastal areas, especially where fine-grained 

sediment occurs in bays and fjords. The shallow waters 

throughout Norton Sound pose a special problem 

regarding oil pollution-resuspension of bottom sediments 

by storm wave and tidal fluctuation. Such resuspension 

could disperse pollutants that had accumulated in the 

bottom sediment throughout the water column. 

Another important pollution consideration is oil 

absorption into and adsorption onto clay minerals, 

especially smectites. Smectite is an expandable clay 

mineral which can accommodate large organic molecules 

(for instance, hydrocarbons) in its crystallographic 

interlayer spaces. This results in retention of oil in 

smectite-rich bottom and suspended deposits and has 

been suggested as a specific problem for suspended 

sediment in Lower Cook Inlet, Alaska (Rein and others, 

1979). However, in central Norton Sound, where smectite 

is abundant in bottom sediment and minor in suspended 

sediment, the clay-sized fraction constitutes only a small 

part of the total sediment. Thus, the potential 

detrimental effect due to absorption of oil by clay 

minerals in bottom and suspended sediment may be 

negligible, except in the shallow bays and fjords that line 

Norton Sound, where muds predominate. 

\ 

\ 

REFERENCES 

Biscaye, P. E., 1965, Mineralogy and sedimentation of 

recent deep-sea clay in the Atlantic Ocean and 

adjacent seas and oceans: Geological Society of 

America Bulletin, v. 76, no. 7, p. 803-832. 

Cacchione, D. A., and Drake, D. E., 1982, Measurements 

of storm-generated bottom stresses on the 

continental shelf: Journal of Geophysical Research, 

v. 87, no. C3, p. 1952-1960. 

Carlson, P. R., Conomos, T. J., Janda, R. J., and 

Peterson, D. H., 197 5, Principal sources and dispersal 

patterns of suspended particulate matter in 

nearshore surface waters of the northeast Pacific 

Ocean: Greenbelt, Maryland, Goddard Space Fli0 ht 

Center, NASA Contractors Final Report No. CR142641, National Technological Information Service, 

p. 26-39. 

Coachman, L. K., and Aagaard, K., 1966, On the water 

exchange through the Bering Strait: Limnology and 

Oceanography, v. 11, p. 44-59. 

Drake, D. E., Cacchione, D. A., Muench, R. D., and 

Nelson, C. H., 1980, Sediment transport in Norton 

Sound, Alaska: Marine Geology, v. 36, p. 97-126. 

0 

I 

0· 

50 KILOMETERS 

I I 

Figure 10. Distribution of illite in near-surface suspended sediment. Values are the percentage of illite in 

the clay-mineral suite and are contoured at a 5-percent interval; contours dashed where approximately 

located. 

14 
Drake, D. E., Totman, C. E., and Wiberg, P. L., 1979, 

Sediment transport during the winter on the Yukon 

prodelta, Norton Sound, Alaska: Journal of 

Sedimentary Petrology, v. 49, p. 1171-1180. 

Dupre, W. R., 1978, Yukon Delta coastal processes study, 

in Assessment of the Alaskan Continental Shelf: 

U.S. National Oceanographic and Atmospheric 

Administration and Bureau of Land Management 

Principal Investigators Report for year ending March 

1978, p. 384-446. 

Fleming, R. H., and Heggarty, D., 1976, Oceanography of 

the southeastern Chukchi Sea, in Wilimovsky, N. J., 

and Wolfe, J ., eds., Environment of the Cape 

Thompson region, Alaska: U.S. Atomic Energy 

Commission, Division of Technical Information, 

PNE-481, p. 697-754. 

Gibbs, R. J., 1967, The geochemistry of the Amazon River 

system; Part 1, The factors that control the salinity 

and the composition and concentration of the 

suspended solids: Geological Society of America 

Bulletin, v. 78, no. 10, p. 1203-1232. 

__ 1977, Clay mineral segregation in the marine 

environment: Journal of Sedimentary Petrology, v. 

47, no. 1, p. 237-243. 

Goodman, J. R., Lincoln, J. H., Thompson, T. G., and 

Zevsler, F. A., 1942, Physical and chemical 

.o 

.o 

o. 

investigations: Bering Sea, Bering Strait, Chukchi 

Sea during the summers of 1937 and 1938: Pullman, 

Washington, University of Washington Publication in 

Oceanography, v. 3, no. 4, p. 105-169, and Appendix, 

p. 1-117. 

Hein, J. R., Bouma, A. H., Hampton, M. A., and Ross, R. 

C., 1979, Clay mineralogy, fine-grained sediment 

dispersal, and inferred current patterns, lower Cook 

Inlet and Kodiak Shelf, Alaska: Sedimentary 

Geology., v. 24, p. 291-306. 

Hein, J. R., Scholl, D. W., and Gutmacher, C. E., 1976, 

Neogene clay minerals of the far northwest Pacific 

and southern Bering Sea: Sedimentation and 

diagenesis, in Bailey, S. W., ed. Proceedings of the 

197 5 International Clay Conference, Willmette, 

Illinois, Applied Publication Limited, p. 71-80. 

Howard, J. D., and Nelson, C. H., 1982, Sedimentary 

structures on delta-influenced shallow shelf, Norton 

Sound, Alaska, in Nelson, C. H. and Nio, S. D., eds., 

The northeaste;; Bering Shelf: New perspectives of 

epicontinental shelf processes and depositional 

products: Geologie en Mijnbouw, v. 61, p. 29-36. 

Husby, D. M., 1969, Report of oceanographic cruise 

U.S.C.G.C. Northwind, northern Bering Sea - Bering 

Strait - Chukchi Sea, July 1969: U.S. Coast Guard 

Oceanographic Report 24, 7 5 p. 

.o .o 

.o 

o. .o 

.o 

.o .o 0· 

.o 

.o 

.o 

/ 0 /' 

.o .o .o ~ '\- __:/, . 

~/ 

~~I / .of\ .s 

0 

I 

50 KILOMETERS 

I I 

Figure 11. Distribution of smectite in near-surface suspended sediment. Values are in percentage of 

smectite in the clay-mineral suite and are contoured at a 5-percent interval; contours dashed where 

approximately located. 

15 
__ 1971, Oceanographic investigations in the northern 

Bering Sea and Bering Strait, June-July 1969: U.S. 

Coast Guard Oceanographic Report 40, 50 p. 

Inman, D. L., and Nordstrom, C. E., 1971, On the tectonic 

and morphologic classification of coasts: J ounal of 

Geology, v. 79, p. 1-21. 

Knebel, H. J., and Creager J. S., 1973a, Sedimentary 

environments of the east-central Bering Sea 

continental .shelf: Marine Geology, v. 15, p. 2.5-45. 

1973b, Yukon River: Evidence for extensive 

--migration during the Holocene transgression: 

Science, v. 179, p. 1230-1232.. 

Lisitsyn, A. P., 1966, Recent sedimentation in the Bering 

Sea (Protessy sovre mennogo osdkoobrazovaniya v 

Beringovom more): Akademiia N auk (Doklady), 

U.S.S.R., Moscow (English translation, 1969, Israel 

Program for Scientific Translations), U.S. 

Department of Commerce, Clearing House for 

Federal Scientific and Technical Information, 

Springfield, Virginia, 614 p. 

McManus, D. A., and Smyth, C. S., 1970, Turbid bottom 

water on the continental shelf of northern Bering 

Sea: Journal of Sedimentary Petrology, v. 40, no. 3, 

p. 869-877. 

\ 

e41 

40 

McManus, D. A., Venkatarathnam, K., Hopkins, D. M., 

and Nelson, H. C., 1974, Yukon River sediment on 

the northernmost Bering Sea Shelf: Journal of 

Sedimentary Petrology, v. 44,. no. 4, p. 1052-1060. 

Moll, R. F., 1970, Clay mineralogy of the north Bering 

Sea shallows: Los Angeles, Calif., University of 

Southern California, M. A. thesis (Report No. USC 

Geol. 70-2), 101 p. 

Molnia, B. F., and Hein J. R., 1982, Clay mineralogy of a 

glacially dominated, subarctic continental shelf: 

Northeastern Gulf of Alaska: Journal of 

Sedimentary Petrology, v. 52, no. Z, p. 515-527. 

Naidu, A. S., Creager, J. S., and Mowatt, T. C., 1982, 

Clay mineral dispersal patterns in the North Bering 

and Chukchi Seas: Marine Geology, v. 47, p. 1-15. 

Nelson, C. H., 1982, Late Pleistocene-Holocene 

transgressive sedimentation in deltaic and nondeltaic areas of the northeastern Bering 

epicontinental shelf, in Nelson, C. H., and Nio, S. D., 

eds., The northeastern Bering Shelf: New 

perspectives of epicontinental shelf processes and 

depositional products: Geologie en Mijnbouw, v. 61, 

p. 5-18. 

0· 

-- -----.43 

0 50 KILOMETERS 

I I 

Figure 12. Distribution of chlorite+kaolinite in near-bottom suspended sediment. Values are in percentage of 

chlorite+kaolinite in the clay-mineral suite and are contoured at a 5-percent interval; contours dashed where 

approximately located. 

16 
Nelson, C. H., and Creager, J. S., 1977, Displacement of 

Yukon-derived sediment from Bering Strait to 

Chukchi Sea during Holocene time: Geology, v. 5, 

no. 3, p. 141-146. 

Nelson, C. H., Pierce, D. E., Leong, K. W., and Wang, F. 

H., 1975, Mercury distribution in ancient and modern 

sediment of northeastern Bering Sea: Marine 

Geology, v. 18, p. 91-104. 

Patton, W. W., 1971, Petroleum possibilities of YukonKoyukuk Province, Alaska, in Cram, I. H., ed., 

Future petroleum provinces- of the U.S.-their 

\ 

\ 

geology and potential: American Association of 

Petroleum Geologists Memoir 15, v. 1, p. 100-104. 

Sharma, G. D., Wright, F. F., Burns, J. J., and Burbank, 

D. C., 1974, Sea-surface circulation, sediment 

transport, and marine mammal distribution, Alaska 

continental shelf: Greenbelt, Maryland, Goddard 

Space Flight Center, NASA Contractors Final Report 

No. CR-139544, National Technology Information 

Service, NASA Contractor Report No. CR-139544, 

77 p. 

0 

I 

50 KILOMETERS 

I I 

Figure 13. Distribution of illite in near-bottom suspended sediment. Values are in percentage of illite in t4e 

clay-mineral suite and are contoured at a 5-percent interval; contours dashed where approximately located. 

17 
18 

\ 

---T50 KILOMETERS 

I I I 

Figure 14. Distribution of smectite in near-bottom suspended sediment. Values are in percentage of smectite 

in the clay-mineral suite and are contoured at a 5-percent interval; contours dashed where approximately 

located. 
172° 170° 

CHUKCHI 

SEA 

U.S.S.R. 

660 + 

I 

I" 

~ 

65° 

+ 

+ + 

BERING SEA 

168° 166° 

+ 

Do 

EXPLANATION 

Modal grain size in millimeters 

~ 0.25-0.35 

0.18-0.25 

0.13-0.18 

~--;::::::;;:::::; 0.09-0.13 

0.06-0.09 

~ <0.06 

---Yukon fine sand deposit 

+ 

0 25 50 75 100 KILOMETERS 

~--~--~--~-1 

Figure 15. Isopach map of Holocene marine sediment in No:t_ton Sound and the adjacent shelf area, based on 

core data and high-resolution seismic data. Figure from Nelson (1982}. 

19 
GPO 587-044/10015