DISTRIBUTION OF BOTTOM SEDIMENTS 

ON THE CONTINENTAL SHELF, 

NORTHERN BERING SEA 

Distribution of Bottom Sediments on the 

Continental Shelf, Northern Bering Sea 

By DEAN A. McMANUS, VENKATARATHNAM KOLLA 

DAVID M. HOPKINS, and C. HANS NELSON 

STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

G E 0 L 0 G I C A L S U R V E Y P R 0 F E S S I 0 N A L P A P E R 7 5 9-C 

Prepared in cooperation with Department of 

Oceanography, University of Washington 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON 1977 
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress Cataloging in Publication Data 

Main entry under title: 

Distribution of bottom sediments on the Continental Shelf, Northern Bering Sea. 

(Studies on the marine geology of the Bering Sea) 

(Geological Survey professional paper ; 759-c) 

Bibliography: p. 

1. Marine sediments--Bering Sea. 2. Ocean currents-Bering Sea. I. McManus, Dean A. II. Washington (State). 

University. Dept. of Oceanography. III. Columbia University. Geological Observatory. IV. Series. V. Series: 

United States. Geological Survey. Professional paper ; 759-c 

GC398.5.D57 551.4'65'51 76-608367 

For ~ale by the Superintendent of Documents, U.S. Go,·ernment Printing Office 

Washington, D.C. 20402 

Stock Number 024-001-02993-6 
CONTENTS 

Page 

Abst:r;act ---------------------------------------------------------------------------------------------------- C1 

Introduction -------------------------------------------------------------------------------------------- 1 

Previous work ---------------------------------------------------------------------------------------- 1 

BathymetrY---------------------------------------------------------------------------------------------- 3 

Oceanographic setting ------------------------------------------------------------------------ 6 

Analyses and within-sample variability -------------------------------------- 6 

Distribution of sediments·------------------------------------------------------------------ 7 

Gravel________________________________________________________________________________________________ 7 

Silt ------------------------------------------------------------------------------------------------------ 10 

Clay---------------------------------------------------------------------------------------------------- 10 

Sand -------------------------------------------------------------------------------------------------- 14 

Page 

Distribution of sediments-Continued 

Sand-Continued 

Texture ----------------------------------------------------------------------------------· C14 

Light minerals_____________________________________________________________________ 14 

Heavy minerals___________________________________________________________________ 14 

Sediment types ----------------------------------------------------------------------------------· 20 

Discussion-------------------------------------------------,------------------------------------------· 22 

Present-day processes of sediment transport------------------ 22 

Sediment dispersal____________________________________________________________________ 24 

Summary and conclusions -----------------------------------------------------------· 27 

References cited·---------------------------------------------------------------------------------· 30 

ILLUSTRATIONS 

Page 

FIGURE 1. Index map of continental shelf in northern Bering Sea·----------------------------------------------------------------------------------------------------------------------- C2 

2. Bathymetric chart of northern Bering Sea showing station locations -------------------------------------------------------------------------------------------- 4 

3-15. Maps of northern Bering Sea showing: 

3. Current measurements-------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 5 

4. Generalized geology ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 8 

5. Gravel distribution -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 9 

6. Silt distribution -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 11 

7. Clay distribution ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 12 

8. Sand distribution------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ 13 

9. Distribution of modal classes of sand -------------------------------------------------------------------------------------------------------------------------------------------- 15 

10. Sorting of bottom sediments -------------------------------------------------------------------------------------------------------------------------------------------------------------- 16 

11. Ratio of plagioclase to K-feldspar ---------------------------------------------------------------------------------------------------------------------------------------------------- 17 

12. Distribution of factors from Q-mode factor analysis of heavy minerals ____________________________________________________________________________ 19 

13. Heavy-mineral provinces -------------------------------------------------------------------------------------------------------------------------------------------------------------------- 21 

14. Sediment types---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 23 

15. Distribution of bottom sediment ------------------------------------------------------------------------------------------------------------------------------------------------------ 28 

TABLES 

Page 

TABLE 1. Variance of texture variables----------------------------------------------------------------------------------------------------------------------------------------------------------------------------C7 

2. Extreme samples in Q-mode analysis of heavy minerals ---------------------------------------------------------------------------------------------------------------------· 18 

3. R-mode factor analysis of sediment size ------------------------------------------------------------------------------------------------------------------------------------------------------ 20 

4. Extreme samples in Q-mode analysis of sediment size -------------------------------------------------------------------------------------------------------------------------- 22 

III 

STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL 

SHELF, NORTHERN BERING SEA1 

By DEAN A. McMANus, 2 VENKATARATHNAM KoLLA, 3 

DAVID M. HOPKINS, and C. HANS NELSON4 

ABSTRACT 

Most of the sediment contributed to the northern Bering Sea 

today (modern sediment) is associated with the Yukon River 

runoff and the high-speed currents (30-40 em/ sec near the bottom) 

within the Alaskan Coastal Water, which sets northward along 

the coast through Bering Strait into the Chukchi Sea. Most 

sediment is silt sized but includes some very fine grained sand and 

clay-sized material. The very fine sand extends northward across 

the mouth of Norton Sound, where it mixes on the west with relict 

Yukon fine sand to form a palimpsest sand, thence grades 

eastward into Yukon silt that covers southern Norton Sound. 

Much of the Yukon silt enters Norton Sound, but there is only a 

thin accumulation there, except near the delta. The silt issues from 

the sound along the north side, where a silt deposit is in presumed dynamic equilibrium, thereby marking the dispersal 

path through a depression into the coastal current. The modern 

silt associated with the coastal current is considered a dynamic 

component of the bottom sediment, which otherwise consists of 

relict sand and gravel. The net transport of the silt is through the 

Bering Strait and into the Chukchi Sea. 

Impressed on the steady north ward -setting current are irregular 

large-velocity fluctuations produced partly by tidal currents and 

partly by the wind regime. For the area as a whole, tidal currents 

and wind drift are believed to be more significant than wave drift 

or estuarine-type density circulation. 

Where the coastal current is strongest, the sediment is a relict or 

resid uallag sand and gravel derived from glacial rna terial or from 

metamorphic bedrock of Seward Peninsula. Under the slower 

Modified Shelf Water offshore of the coastal water, the bottom 

sediment also is relict, in part relict Yukon sand, in part derived 

from glacial moraines. Modern sediments do not accumulate 

beneath the Modified Shelf Water, as they do beneath the coastal 

water. 

Northern Bering Sea was subaerially exposed during the period 

of eustatically lowered sea level _that coincided with the last 

glaciation. However, the surface sediments provide no indication 

that the Yukon River has ever drained northward into the Arctic 

Ocean. Until relatively recent time, the Yukon drained southward 

into southern Bering Sea. The river mouth has been in its present 

northern position for only a geologically brief period. 

Seaward size grading in relict sands is ascribed to the presentday strong current paralleling the isobaths. 

'Contribution 825 of the Department of Oceanography, University of Washington, 

based on work done as part of a joint research program by the U.S. Geological Survey 

and the University of Washington and financed by the U.S. Geological Survey. 2Department of Oceanography, University of Washington, Seattle, Wash. 98105. 

"Lamont-Doherty Geological Observatory, Columbia University, Palisades, N.Y. 

10964. 

•U.S. Geological Survey, 345 Middlefield Road, Menlo Park, Calif. 94025. 

INTRODUCTION 

The continental shelf in the Bering Sea is one of 

the largest in the world. Even the shallow, 

northernmost part of the shelf formed by the 

Chirikov Basin and Norton Sound (fig. 1) covers an 

area of 11 x 104 km2 , approximately the area of the 

shelf in the western Gulf of Mexico from the 

Mississippi Delta to the mouth of the Rio Grande. Yet 

for the Chirikov Basin and Norton Sound, only a 

very general picture of the shelf sediments has been 

available. The purpose of this study is to evaluate the 

role of modern sedimentary processes in the region 

and to seek a better definition of sediment 

provenance. A brief summary of part of this work is 

given in an earlier work (McManus and others, 197 4). 

PREVIOUS WORK 

A brief description of the bottom sediments of the 

Bering Sea and a summary of cruises to the study 

area prior to 1965 are pre sen ted by Creager and 

McManus (1967), who noted the presence in Norton 

Sound of modern sediment from the Yukon River but 

considered the sediment in the Chirikov Basin to be 

relict. A detailed study by McManus, Kelley, and 

Creager (1969) concentrated on the Chukchi Sea 

north of Bering Strait, concluding that the Chirikov 

Basin sediment was not masked by the modern silts 

from the Yukon River, as the Yukon sediment was 

being transported across the basin and into the 

Chukchi Sea as a turbid layer in the lower part of the 

water column. Subsequently, the particle size and 

concentration of suspended material in the water 

column were measured by McManus and Smyth 

(1970), further substantiating the significance of this 

process in transporting silt and clay across the floor 

of northern Bering Sea. 

The identification of silt and sand of Yukon origin 

is based, incidentally, upon study of the mineralogy 

and texture of a body of sediment clearly of 

terrigenous origin that thickens toward the present 

Cl 
C2 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

100 200 MILES 

1 I I I I I 0 100 200 KILOMETERS 

ISOBATHS IN METERS 

0 

I r I 1 

0 

50 MILES 

I I I I I 

50 KILOMETERS 

SIBERIA 

SHPANBERG 

STRAIT 
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C3 

mouth of the Yukon River (McManus and others, 

1974). No samples were available to us from within 

the river itself, and there are as yet no published 

descriptions of the bed and suspended load of the 

Yukon River near its mouth. 

In order to provide information on the provenance 

of the sand-sized sediment, a study was begun of the 

heavy minerals; preliminary results and tabulated 

data have been presented by Venkatarathnam 

(1971). Detailed studies of the sediment texture and 

gold content in the nearshore area off Nome (Nelson 

and others, 1969; Nelson and Hopkins, 1972) 

produced a better understanding of the complexities 

of sediment distribution near the shoreline. Descriptions of sedimentary features recorded by seismic 

profiling are included in the works of Grim ~nd 

McManus (1970) and Tagg and Greene (1973). 

Detailed bathymetric charts of the Chirikov Basin 

were recently completed (National Ocean Survey 

Maps 1215-10 [1971], 1714-12 [1973], and 1814-10 

[1973]). 

BATHYMETRY 

The description of the bathymetry that follows is 

based upon and uses the physiographic subdivisions 

proposed by Hopkins, Nelson, Perry, and Alpha 

(1976) for the Chirikov Basin area. 

The water depth in the Chirikov Basin exceeds 50 

min only a few places; in Norton Sound depths are 

generally less than 20m (fig. 2). An average depth for 

the entire region might be placed at 30m. Because 

the depth is shallow and the area large, bottom 

gradients are very low, even for a continental shelf. 

The gradient down the Chirikov Ramp (fig. 1) is only 

0.1 m/km between the 30-m and 50-m isobaths, the 

relatively steep slope off Nome only 3 m/km. Nonetheless, within the broad saucer of the study area, 

small relief features occur that are significant in 

interpreting the sediment distribution. 

The greatest water depths in the study area 

(>150 m) are in the fiords along the Chukotka 

Peninsula; little else is known of the nearshore 

bathymetry along this coast. Offshore from ChuFIGURE 1.-Index map of continental shelf in northern Bering 

Sea showing major physiographic units and sources of bathymetric data for figure 2. Bathymetry west ofline A is contoured 

from data on U.S. Defense Mapping Agency Hydrographic 

Center charts. Bathymetry between lines A and B is from 

National Ocean Survey charts cited in text. Bathymetry east of 

line B is from CreagH and McManus (1967). Modified from 

McManus, Venkataratham, Hopkins, and Nelson (1974). 

kotka is one of the main bathymetric features, the 

Chukotka Trough, a shallow depression extending 

northeastward from Anadyr Strait to the Bering 

Strait. The deepest part of the trough is a closed 

depression that terminates northward against a low 

scarp that lies en echelon with the fault-controlled 

northern margin of Port Clarence Valley, a 

prominent sea valley extending parallel to the coast 

of Seward Peninsula eastward as far as Port 

Clarence (fig. 1). 

A prominent ridge of diverse surface topography, 

the Gambell Shoal, extends northeastward from the 

western part of St. Lawrence Island. Farther 

northeast, the Chukotka Trough is adjoined by the 

Chirikov Ramp, a gently sloping surface indented by 

many shallow branching swales suggestive of a 

north ward draining subaerial stream system. The 

eastern part of the Chirikov Basin and much of 

Norton Sound is underlain by the Norton Plain, a 

region of monotonously flat topography that extends 

eastward to the delta of the Yukon River. A broad, 

low ridge extending parallel to the coast of St. 

Lawrence Island diversifies the southwestern corner 

of the Norton Plain. The Savoonga Depression, a 

sharply defined depression with maximum water 

depths exceeding 50 m, lies off the north-central 

coast of St. Lawrence Island. Hopkins, Nelson, and 

Perry (unpub. data, 1973) show that the depression 

results from the faulting and folding of underlying 

Tertiary sedimentary rocks but that the bottom 

topography is diversified by intrusive volcanic plugs 

and by ridges formed by submarine fissure eruptions 

of Quaternary age. 

A south-trending depression, the St. Lawrence 

Trough, lies just off the east end of St. Lawrence 

Island. Water depths in this sea valley exceed 40 m. 

The presence of fault scarps (Grim and McManus, 

1970) and closure of the bathymetric contours suggest that tectonic activity may be involved in the 

origin of the sea valley, but scouring by strong northsetting currents and stream erosion during intervals 

of low sea level may have played a role. Northward 

the St. Lawrence Trough terminates abruptly against 

a broad constructional ridge, the Northeast Cape 

Shoal. Other large shoals and depressions trend 

northward in Shpanberg Strait east of the St. 

Lawrence Trough. 

The floor of Norton Sound is not marked by a 

continuous gradient away from the Yukon Delta; 

rather, it contains an east-trending depression separated from the Chirikov Basin by a broad ridge 
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Perry, and Alpha (1976). 

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DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C5 

extending north from the Yukon River delta. Deep 

passages extend along the coast off Cape Darby and 

Rocky Point. Another long, narrow depression off 

Nome is separated from the central depression by an 

east-trending shoal. 

64° 

EXPLANATION 

0-\0m I0-30m 30mtobottom 

Depth and direction of current 

Current speed shown by length of arrow. 

See scale below 

0 50 

I I I I I I 

CURRENT SPEED, IN 

CENTIMETERS PER SECOND 

170° 

BERING SEA 

The region off the coast of Seward Peninsula 

between Sledge Island, Port Clarence, and King 

Island constitutes the Cape Rodney Parallel Valley 

Area, a region of low, widely spaced ridges and 

troughs trending northwestward. This province is 

168° 166° 164° 162° 

CHUKCHI SEA 

V \/lV} 

" 

A L A S K A 

64° 

NORTON SOUND 

FIGURE 3.-Current measurements during early July 1968. Sites of measurement are at bases of arrows. (Mter Coachman and 

others, 1976, with permission of University of Washington Press). 
C6 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

succeeded to the northwest by the Point Spencer 

Shoal Area, which contains a series of large constructional shoals having crests at approximately 

10, 20, and 30 m. Sand waves occur at about 20 m 

depth on the western flanks of the 10-m shoal (Grim 

and McManus, 1970). 

OCEANOGRAPHIC SETTING 

Hydrographic data are available for only the 4-

month open season, when the hydrographic regime 

is constituted of warm ( >8°C), less saline (<.31 ° /oo) 

water along the Alaska coast, and cold, more saline 

water offshore. The Alaskan Coastal Water, formed 

largely by river runoff from the coastal lowland 

between Bristol Bay and the Yukon River, borders 

that coast, fills Norton Sound, and again borders the 

coast from Nome through the Bering Strait and into 

the Chukchi Sea. Steep horizontal gradients in temperature and salinity mark the boundary with the 

Modified Shelf Water offshore (see figures in McManus and Creager, 1963, and McManus and others, 

1969), which originates in the northern Bering Sea 

during winter ice formation (Sauer and others, 1954). 

Although warmed above the< 0°C temperatures of 

the Deep Shelf Water, the Modified Shelf Water is 

still cold (0°-4°C) and ranges in salinity from 31.5 to 

33°/oo. 

Both the Alaskan Coastal Water and the Modified 

Shelf Water have a net movement northward through 

Bering Strait (fig. 3) as a result of a sea-surface slope 

(Coachman and Aagaard, 1966). The cause of the 

difference in sea level between the Bering and Chukchi Seas is unknown. At 20-m water depths southeast 

of Bering Strait, current velocities of 30-50 em/sec 

have been measured in the coastal water. In the 

Chirikov Basin, the rates drop to 10-30 em/sec. A 19-

hour anchor station measured velocities of 4-16 

em/sec within 1 m of the bottom in this basin (R. 

Sternberg, written commun., 1971). 

Two types of major velocity fluctuations oocur in 

the persistent northerly setting current. Regular 

fluctuations of 50-70 percent of the mean velocity 

appear to have a tidal origin (Coachman and Aagaard, 1966; Coachman and Tripp, 1970). In addition, 

the general current velocity may fluctuate as much 

as 100 percent over a period of a day or more, 

presumably as a result of major changes in atmospheric pressure or the wind regime (Coachman and 

Tripp, 1970). Winds produce storm surges or setups 

raising sea level as much as 4 m along the southern 

coast of Seward Peninsula (U.S. Coast and Geodetic 

Survey, 1964). 

The generally northward flow of the entire water 

column has a direct effect on the coastal water where 

westward-extending promontories deflect the flow 

(Fleming and Heggarty, 1966). The less dense coastal water is piled up against the shore as a thickened 

section, and strong currents are produced to move 

the water, as along south western Seward Peninsula. 

Under these conditions, relatively warm and dilute, 

high-velocity water in the area between the shore 

and the eastern boundary of the Chirikov Ramp is 

set north ward. At times when prolonged northerly 

winds greatly restrict the flow into the Chukchi Sea, 

however, the coastal water spreads out as a surface 

layer on the denser Modified ShelfWaterratherthan 

occupying the entire water column from the shore of 

the Seward Peninsula to the Chirikov Ramp. 

A more complete bibliography of the physical 

oceanography is given in McManus, Kelley, and 

Creager (1969). 

ANALYSES AND WITHIN-SAMPLE VARIABILITY 

Samples collected from the stations shown on 

figure 2 were analyzed for sediment texture by 

standard sieve and pipette techniques. The approximately 250 samples with complete analysis include 

those reported on by Creager and McManus (1967) 

and McManus, Kelley, and Creager (1969). The 

graphical estimates of Folk and Ward (1957) were 

used to describe the grain-size distribution. 

Of the 204 heavy-mineral separates made by methylene iodide (sp. gr. 3.14-3.17), 120 were examined to 

identify the minerals in the 1-2.75<!> and the 2. 75-4.00 

¢J size fractions. The data on the percent of heavy 

residue and of individual heavy minerals in each of 

the two sizes have been reported elsewhere (Venkatarathnam, 1971). Only the 2. 75-4.00 <P size fraction is 

considered in the present paper. Light minerals and 

pebbles of selected samples were studied by staining 

and petrographic techniques, respectively. 

In order to estimate the significance of these data, 

it is necessary to have some measure of the variability associated with the data points. Although 

such measurements can be based upon replicate grab 

samples at a station and replicate splits of a grab 

sample, Kelley and McManus (1969; 1970) report that 

most of the variability for stations on the continental 

shelf off Washington is associated with betweensplits variation within a grab sample, rather than 

between-grab sample variation within a station. 

In the present study, replicate grab samples were 

not taken, but replicate splits of 36 grab samples 

were analyzed for sediment texture. The number of 

splits was not constant but ranged from 1 to 8 per 

grab. Replicate analyses of mineral composition 

were too few for a statistical evaluation, as emphasis 
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C7 

TABLE I.-Analysis of variance table for texture variables 

[SS - sum of squares; df- degrees of freedom; MS - mean square] 

Variable sv ss 

Percent gravel ·····-··········------·-···· Grabs 58823.55 

Splits 5569.23 

Percent sand ··················-············· Grabs 88766.50 

Splits 8659.49 

Percent silt ················----------·--------- Grabs 46185.56 

Splits 4929.36 

Percent clay ---------------------------------- Grabs 1836.20 

Splits 855.45 

Median ·-···----------·--···-··-··-···· ···· ······ Grabs 388.14 

Splits 44.83 

Mean ········-------------------------------------· Grabs 377.98 

Splits 52.98 

Standard deviation -- ------------------ Grabs 109.15 

Splits 22.39 

Skewness -------------------····-------·----··- Grabs 8.65 

Splits 6.24 

Kurtosis ··············--·······---------·-·-···· Grabs 201.77 

Splits 180.24 

Mode ·······--------------·--····---····-·····-·--- Grabs 789.92 

Splits 56.20 

was placed upon a reconnaissance coverage of the 

study area. 

A one-way analysis of variance based upon the 

random-effects model was used to provide the results 

on sediment texture (table 1). There was no data 

transformation. The F-ratios compare the variability 

between grab samples (and since only one grab 

sample was taken at a station, this variability can be 

thought of as between-station variability) with the 

variability between splits of the grab sample. For all 

variables, the F-ratio is significant with greater than 

95 percent confidence; this means that· there is 

greater variability between grab samples(" stations") 

than within them. Had this not been the case, further 

discussion of geographic distribution of the variables would have been statistically meaningless. 

The different values of the F-ratio indicate that 

some variables are more diagnostic of differences 

between grab samples than others (Kelley and McManus, 1969; 1970). The modal size and percents 

gravel, sand, and silt show the most recognizable 

between-grab differences; percent clay, skewness, 

and kurtosis are less efficient. As a measure of the 

degree to which the variables are sensitive to betweengrab differences, the minimum resolvable difference 

between means of grab samples can be computed by 

using a measure based upon the power of the F-test 

(Mcintyre, 1963; Kelley and McManus, 1969; 1970). 

Because the number of splits was not constant, n8 

in the equation of Kelley and McManus (1969) has 

been approximated by n 0 according to the method of 

Snedecor (1956, p. 269). The minimum resolvable difference for each variable, presented in table 1, should 

be used only in a broad sense, as representing 

df MS F Minimum resolvable 

difference 

35 1680.67 28.972 9.9 percent 

96 58.01 

35 2536.19 28.117 12.4 percent 

96 90.20 

35 1319.59 25.698 9.3 percent 

96 51.35 

35 52.46 5.888 3.9 percent 

96 8.91 

35 11.09 23.596 .89 ¢'unit 

96 .47 

35 10.79 19.618 .97 ¢J unit 

96 .55 

35 3.12 13.565 .63 

96 .23 

35 .25 3.571 .35 

96 .07 

35 5.76 3.064 1.79 

96 1.88 

35 22.57 38.254 1.00 ¢J unit 

96 .59 

minimum significant contour intervals, not to compare specific values of two adjacent stations for 

significance in relation to a common population. 

DISTRIBUTION OF SEDIMENTS 

GRAVEL 

Gravel and gravel-rich sediments occur (1) in 

Bering, Anadyr, and Shpanberg Straits, (2) in a belt 

approximately 30 km wide along most of the. coast 

from east of Nome to the Bering Strait, (3) in the 

northern part of the Chukotka Trough, (4) in a belt 

about 10 km wide along the north coast of St. 

Lawrence Island, and (5) in a· narrow belt that 

extends some 60 km northward from St. Lawrence 

Island along the eastern boundary of Gambell Shoal 

(figs. 4 and 5). Although ice-rafting may play a role in 

the distribution of pebbly muds, the gravel deposits 

observed in detailed studies near Nome are relict or 

residual and are derived from glacial drift, outwash, 

alluvium, and bedrock distributed in a complex 

pattern in the nearshore area (Nelson and Hopkins, 

1972). The coarse deposits near Nome form an 

irregular belt parallel to shore seaward from the 

modern nearshore sand body; the coarse deposits 

extend seaward in lobes reflecting offshore distribution of glacial drift and bedrock outcrops. This same 

model of complex gravel distribution probably obtains for all the gravel regions of northern Bering 

Sea. The lithology of the submerged gravel in the 

central and eastern part of the study area is closely 

related to the lithology of adjacent coastal areas, 

whereas the gravel of the western part consists 

largely of exotic material. 
C8 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

Basaltic volcanic rocks from nearby Quaternary 

eruptive centers predominate in the nearshore zone 

off the mountains of central St. Lawrence Island 

(fig. 4). Gravel off the east coast of St. Lawrence 

Island consists predominantly of granite, limestone, 

and sedimentary rocks of local derivation. Along the 

174" 172" 170" 

50 0 

50 0 50 KILOMETERS 

[§] . 

. 

Sediments 

Alluvium, glacial drift, windblown silt, and marine deposits 

~ . 

0 

Sedimentary rocks 

Includes some volcanic tu,ffs on 

St. Lawrence Island 

Sedimentary ~ rocks 

lJKjvt l 

Volcanic rocks 

B 

Basaltic volcanic 

rocks 

Plutonic 

-

rocks 

168" 166" 164" 162" 160" 

C H U K C HI S E A 

EXPLANATION 

Sedimentary ~ rocks 

Includes small area s of Triassic 

rocks on St. Lawrence Island 

1>~<1 Lf;~J 

Sedimentary and metamorphic rocks 

Largely Precambrian 

Metamorphic rocks 

Includes some rocks of 

Precambrian age 

----:----? --... ? .... 

Contact 

Queried wlwre inferred ----?--?-

Major fault 

Queried wlwre inferred 

Axis of Norton Tertiary basin 

FIGURE 4.-Generalized geologic map of land areas around northern Bering Sea (Nelson and Hopkins, 1972). 

66' 

64" 

' 

w_ Ou 

...JQ 

<I;N 

D.. 

I 

~z 

<!;<~; 

uwo: 

o:aJ 

D.. 
173° 172° 171° 170o 169° 168° 167" 

65° 

64°"---

30 

63°•--

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS IN METERS 

.. 

~~~ ' I It I I L I "O" ''>" .... 

167• 

166° 165° 

20 

if 

166° 165° 

164° 163° 162° 

l 

r:.;f_\/v~:.RL· PEI,J:i,JSUL A 

161° 

I 

165° 

I 

-~63° 

-~ .. ·_· _L I 

,.,. 1620 --~ 1610 

FIGURE 5.-Distribution ofweightpercentgravelin bottom sediments. ContourintervallOpercent. "More than" values are shown in nearshore areas where gravel content 

is high and increasing shoreward. 

tj 

~ 

00 

1-3 

~ ~ 

eo 

e 

1-3 

0 

z 

0 

~ 

eo 

0 

~ 0 

== 00 

t:r::l 

tj 

;: 

t:r::l 

~ 00 

0 

z 

1-3 

::r: 

t:r::l 

C1 

0 

z 

1-3 

z 

t:r::l 

z 

;; 

t-t 

00 

::r: 

tz:j 

~~ 

z 

0 

~ ::r: 

t:r::l 

~ 

z 

eo 

t:r::l 

~ 

z 

Q 

00 

tz:j 

> 

0 

~ 
C10 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

Seward Peninsula coast from Solomon to Port 

Clarence, offshore gravel is predominantly quartzite, quartz-mica schist, garnet-hornblende schist, 

marble, lime-silicate rocks, and vein quartz derived 

from the local low-grade metamorphic terrane. 

Between Cape Nome and Cape Wooley, the gravel 

consists of granitic rocks and high-grade metamorphic rocks derived from mountains a few tens of 

miles inland and from two coastal plutons. 

A very different suite of rock types is found in 

gravel along the Seward Peninsula coast westward 

from Port Clarence, near King Island, in Bering 

Strait, in Anadyr Strait, along the coast of western 

St. Lawrence Island, and in the finger of gravel 

extending north ward from central St. Lawrence 

Island. Volcanic rocks of acid and intermediate 

composition (dacite, rhyodacite, quartz latite, and 

andesite) and plutonic rocks of varied composition 

ranging from granite to gabbro are prominent and 

commonly predominate in gravel samples from these 

areas. Acid and intermediate volcanic rocks are not 

present in the bedrock of western Seward Peninsula 

and the smaller islands of Bering Sea, but are widely 

distributed in the Chukotka Peninsula and on western St. Lawrence Island. There is abundant evidence 

to indicate that the gravel of the western part of the 

Bering Sea consists largely of relict morainal material derived from the Chukotka Peninsula (Hopkins 

and others, 1969; Silberman, 1969; Grim and McManus, 1970; Hopkins and others, 1972; Nelson and 

Hopkins, 1972). Our detailed studies, however, in· 

dicate that slate and limestone from the York Mountains mixed with volcanic rocks from Chukotka are a 

major constituent in the nearshore gravel between 

Port Clarence and Bering Strait. Unpublished studies 

by Hopkins indicate that clasts eroded from submerged outcrops of serpentinite and gabbro are 

mixed with the glacially transported relict gravel in 

some areas near St. Lawrence Island. 

In the region north and west of western St. Lawrence 

Island, copper sulfide mineral grains of presumed 

Chukotka origin are present in some pebbles of 

altered andesite and diabase. Native copper has been 

found in the sand-sized component of samples from 

this region. 

SILT 

The distribution of the mud (silt plus clay) component leads to insights that help us understand the 

sand distribution. Therefore, we shall discuss the 

distribution of silt and clay before discussing the 

pattern of sand distribution. 

The highest silt percentages are associated with 

the Yukon River and with some depressions in the 

sea floor (fig. 6). The area of high silt abundance 

extends northward, down current from the delta, 

apparently in fingerlike projections. Although the 

axial shoal and depression in Norton Sound have a 

low silt content, the depression along the northern 

margin of the shoal contains silt in nearly the same 

proportion as found near the Yukon mouth. Silt 

dominates sediments in this depression farther east, 

near Nome, but only on the south side, rather than in 

the depression proper. A tongue of sediment containing more than 10 percent silt extends northwestward from Sledge Island toward King Island, 

but little silt is present in the bottom sediments on 

either side. This northwest-trending tongue of silty 

sediment is independent of the topography. Northwest-trending ridges and troughs are present both in 

the area of silty sediment and in areas to either side 

where the silt content is less than 10 percent. 

In Shpanberg Strait the silt content decreases 

rapidly westward from the Yukon Delta to a point 

about 75 km offshore, where it stabilizes at 10-20 

percent. Bottom sediments on the shoals have a silt 

content of less than 10 percent, but silt constitutes 

more than 30 percent of the sediment in the easternmost depression in Shpanberg Strait. A relatively 

high silt content characterizes the sediments in the 

depression along the north coast of eastern St. 

Lawrence Island. 

The northern part of the Ch ukotka Trough is 

characterized by a slightly higher silt content. This 

mainly is the smoother and flatter floored part of the 

trough, although the closed depression just south of 

Bering Strait is also included. A high silt content 

marks the western flank of Prince of Wales Shoal; 

this silt extends northward from Cape Prince of 

Wales into the Chukchi Sea. 

CLAY 

The distribution of clay-sized particles (fig. 7) is 

contoured at the minimum resolvable difference, 4 

percent. The low F-ratio indicates that this variable 

is not so diagnostic of differences between grab 

samples (stations) as the silt, which, however, has a 

similar pattern. Presumably, the lesser effectiveness 

of the clay percent in distinguishing between grab 

samples is associated with the generally low percentage of this size particle in most of the samples. 

In an analysis of the clay mineralogy of 24 selected 

samples from the study area, Moll (1970) concluded 

that there were two clay mineral assemblages. The 

western assemblage (west of the dashed line in fig. 7), 

considered to be the Chirikov Basin assemblage, 

contains a larger amount of collapsible components 

and lower values of illite and chlorite. Clay minerals 
173" 17ZO 1"71° 170° 169° 168° 16"(0 166° 165° 164° 163° 162° 161° 

65°,--

--65° 

64° 

63°~-

---"63° 

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS IN METERS 

~ 

----L---------_L____ I I _j 

172° 171• 170° 

~------~-----_____._-

164° 163° 162° 161° 167" 166° 165" 

FIGURE G.-Distribution of weight percent silt in bottom sediments. Contour interval 10 percent, approximately the minimum resolvable difference (9.3 percent). The 

patchiness is statistically significant. 

t:1 

~ ~ ttl 

c: 

~ 

0 

z 

0 

~ 

ttl 

~ 0 

s;:: 

00 

tz:j 

t:1 

S2 

tz:j 

~ 00 

0 

z 

~ 

:I:: 

tz:j 

(") 

0 

~ ~ 

z 

tz:j 

z 

;; 

t"'4 

00 

:I:: 

tz:j 

t"'4 

~~ 

z 

0 

~ :I:: 

tz:j 

~ ttl 

tz:j 

~ 

z 

0 

00 

tz:j 

> 

0 

....... 

....... 
173° 172° 171° 170° 169° 168° 167° 166° 165° 164° 163° 162° 161° 

:,t WM'IO FT~JiNSUL A 

-~ 65° 

64° 

63° 

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS IN METERS 

171° 170• 

167" 162° 166° 165° 164° 163° 161° 

FIGURE ?.-Distribution of weight percent clay in bottom sediments. Contour interval4 percent. The dashed line separates two clay-mineral assemblages. The western 

assemblage is consid.ered to be the Chirikov Basin assemblage; the eastern assemblage the Yukon River assemblage. 

0 

...... 

~ 

~ c 

t:l 

1-4 

t'J!j 

00. 

0 

z 

t-3 

::I: 

t'J!j 

~ ~ 

z 

t'J!j 

0 

t'J!j 

0 

t"" 

0 

0 

to< 

0 

~ 

t-3 

::I: 

t'J!j 

t:O 

t'J!j 

~ 1-4 

z 

0 

00. 

t'J!j 

> 
173" 172" 171" 170" 169° 168° 167° 166" 165" 164° 163° 162" 

·----;v---r---r----

~ ---! 

SPE~JCER 

~E_ Vv,.\RO F-'E r,J!r·JSUL.A 

65° 

63"•-

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS IN METERS 

---~----_j 

171" 170• 

167" 166" 165" 164° 163" 

FIGURE B.-Distribution of weight percent sand in bottom sediments. Contour interval 13 percent. 

161" 

-~64° 

--63" 

162° 161° 

t:1 

~ ~ tt1 

c:: 

t-3 

0 

z 

0 

1-:rj 

tt1 

~ 0 

.r:n == 

t_!!j 

t:1 

~ 

~ r:n 

0 

z 

t-3 

::r: 

t_!!j 

0 

0 

z 

t-3 

1-4 

z 

t_!!j 

r:n 

~ 

~ 

~~ 

z 

0 

~ 

t-3 

t:r:: 

t_!!j 

~ 

z 

tt1 

t_!!j 

~ 

z 

C) 

r:n 

t_!!j 

> 

0 

...... 

CI.J 
C14 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

of the eastern assemblage (east of this line) have an 

inverse ratio and appear to be associated with the 

present-day Yukon River sediment. 

SAND 

TEXTURE 

The distribution pattern of percent sand (fig. 8) is 

merely the complement of the sum of the other 

distributions because of the closed-number system. 

The pattern does, however, more clearly indicate the 

high sand content of the shoals at the western tip of 

St. Lawrence Island, in Port Clarence, in Shpanberg 

Strait (particularly the western shoal), and in Norton 

Sound. Variation within the uniformly sandy Chirikov Basin is not depicted, as the use of a smaller 

contour interval would produce unreliable results. 

Instead, the distribution of the modal class is used 

(fig. 9). 

The large F-ratio for the mode indicates that this 

variable is very diagnostic in differentiating between grabs (stations), but it should be noted that the 

class interval used in figure 9 is one-half the minimum resolvable difference (table 1). The pattern 

shown is therefore statistically questionable, though 

geologically reasonable. 

One of the sedimentary characteristics illustrated 

by a distribution of modal sizes is grading, commonly presented as a function of water depth or 

distance from shore. In the present study area, there 

are two prominent examples of size grading. In the 

eastern part of Shpanberg Strait, grading is from 2.5-

3.0 if> sand to the finer-than-4 </>material that covers 

most. of Norton Sound. The 3.0-3.5 ¢ and 3.5-4.0 </> 

sands seem to be closely associated with the silt 

distribution pattern and to form a pattern distinctly 

different from that of the 2.5-3.0 </> mode that dominates Shpanberg Strait. 

The second example of size grading begins with 

the medium sand (1.5-2.0 </>) in the nearshore part of 

the Cape Rodney Parallel Valley Area. Seaward, the 

mode is 2.0-2.5¢ down the eastern flank of the Chirikov Ramp area. It is 2.5-3.0 ¢ throughout the rest of 

this province and becomes 3.0-3.5 ·r/Jin the Chukotka 

Trough to the west and in the southern part of the 

Norton Plain. In the center of the Chukotka Trough 

and near eastern St. Lawrence Island, the mode is 

3.5-4.0 if>. This size grading extends to the secondary 

mode in each of these modal zones. The secondary 

mode in the coarser grained zone is the same as the 

primary mode in the adjacent finer grained zone. As 

comparison with the bathymetric chart shows (fig. 

2), however, this size grading cannot be related 

directly to either water depth or distance from shore. 

Most of the bottom sediments in the study area are 

poorly to very poorly sorted (fig. 10). The very poorly 

sorted sediments are gravels or silts. The best sorting 

is found in the sands near the Yukon, off some 

beaches, and at two depths on various shoals, 34m 

and 20 m, the shallower depth being the crest of 

some shoals. 

LIGHT MINERALS 

Thirty-six samples were analyzed for light minerals in the 2.75-4.00</>class. Quartzformsmorethan 

50 percent of the fraction in samples from the eastwest shoal in Norton Sound and in the northern half 

of the Chirikov Basin. Elsewhere feldspar is the 

major component. A plot of the ratio of plagioclase to 

K-feldspar (fig.11) shows a dominance of plagioclase 

near the Yukon River, including most of Norton 

Sound and Shpanberg Strait, and near the basalts of 

central St. Lawrence Island. K-feldspar predominates in samples from off the east and west ends of 

the island and is the dominant feldspar in most of 

the Chirikov Basin. In northeastern Norton Sound, 

the K-feldspar content is high but not dominant. 

HEAVY MINERALS 

The heavy-mineral content of the totall-4 </>sand 

class, disregarding beach samples, rarely exceeds 10 

percent, although a maximum of 78 percent was 

recorded. For the fine sands (2. 75-4.00 if> class), which 

include the most common modal sizes, heavymineral contents exceeding 16 percent are observed 

in brownish sand at depths of 34-36 m west of St. 

Lawrence Island, adjacent to the volcanic rocks of 

the central part of the island, on the shoal crests (20 

m) in Shpanberg Strait, along the Nome coast, and in 

the Cape Rodney Parallel Valley Area and the Point 

Spencer Shoal Area (Venkatarathnam, 1971). 

Venkatarathnam (1971) lists the heavy-mineral 

assemblages and delimits a number of heavymineral provinces on the basis of the total sand (1-4 

cP) fraction. In an attempt to better define the relations among provinces, 100 samples of the 2.75-

4.00 </> fraction were subjected to a Q-mode factor 

analysis following the procedure of Imbrie and van 

Andel (1964), with the constraint that the mineral 

data (percentages) were transformed into percent of 

range, even though, as Imbrie and van Andel (1964, 

p. 1144) point out, "the proportionally large standard 

error of small percentages produces very noisy data." 

Consequently, our use of the percent range transformation is open to question; on the other hand, 

ignoring the minerals present in small percentages 

could mean ignoring some very important minerals 

(Blatt, 1967). 
0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISO BATHS IN METERS 

J72"' 

MODAL SIZE 

Coarser than 1.0-1.5 ~ 

1.0- 1.5 

1.5-2.0 

2.0-2.5 

2.5-3.0 

3 .0-3.5 

3.5-4.0 

Finer than 4.0 ~ 

FIGURE 9.-Distribution of modal classes of sand. The class interval is less than the minimum resolvable difference. 

I::' 

~ ~ to 

c::: 

~ ..... 

0 

z 

0 

'"%j 

to 

0 

~ 0 

~ 

en 

tJj 

I::' 

~ tJj 

z 

@ 

0 

z 

~ 

:I: 

tJj 

(1 

0 

~ 

z 

tJj 

z 

~ t:-< 

en 

:I: 

tJj 

t:-< 

_'"':j 

z 

0 

~ :I: 

tJj 

:;1:1 

z 

to 

tJj 

~ 

z 

0 

en 

tJj 

> 

Cl 

,_. 

CJl 
173" i65" 16 4 " 

Phi 

unit 

0. 63 

1. 2 6 

1.89 

2 . 5 2 

65" 3. 1 5 

3.78 

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBAT HS IN METERS 

f72" 

FIGURE 10.-Sorting of bottom sediments. Contour interval 0.63¢ unit. 

163" 162~ (.I" 

-.-----· ~----

PLANATlON 

SORTI NG 

We ll so rt ed 

Moderately sort ed 

Poorly sort ed 

} Ver y poorl y sorted 

Extremely poorl y sorted 

163" 

i. f 6')" 

I 

- ~ 64" 

'63° 

0 

...... 

O'l 

~ c::: 

t:l 

...... 

t':l 

w 

0 

z 

>-3 

:I: 

t':l 

s:: 

~ 

z 

t':l 

0 

t':l 

0 

s 

0 

><: 

0 

~ 

>-3 

:I: 

t':l 

ttl 

t':l 

::d 

z 

0 

w 

t':l 

> 
tj -

en 

>-3 

l:lj -to 

c EXPLANATION i >-3 

FELDSPAR RATIO i 

-0 i z i 

> 4 

I 

0 

2- 4 "%j 

1-2 to 

I 0 

0. 5-1 

0.25-0. 5 I ~ 

) ~65' 0 

<0.25 I ~ 

en 

M 

tj -

~ 

M 

z 

>-3 

en 

0 

z 

>-3 

::I: 

M 

(") 

0 

z 

>-3 -

z 

M 

z 

>-3 

> t"' 

en 

::I: 

M 

t"' 

_"%j 

z 

0 

~ ::I: 

M 

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS I N METE AS l:lj 

z 

172" to 

M 

l:lj -z 

0 

en 

M FIGURE 11.- Ratio of plagioclase to K-feldspar in the 2.75-4.00 ¢class. 

> 

0 

1-' 

-..J 
C18 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

TABLE 2.- Values of 13 variables for samples of four highest loadings for each factor in Q·mode analysis of heavy-mineral composition 

"' "' ~ ~ "' "' >< >< Factor Samp "' le "' ,. g g 0 

"' "' .D ~ c. c. ~ :.a 'B 0 0 0 

.D c. ., " .s .5 t: u E ·s. 0 «: "-1 

I TT018-23 1.000 16 32 5 7 

TT018-22 .998 18 32 10 6 

69ANC- 116 .919 15 32 5 14 

69ANC-111 .910 12 34 16 9 

II ............ GR493-A 1.000 4 3 9 

VC067-116 .957 <0.5 3 6 13 

VC067-99 .947 1 4 5 24 

VC067-67 .936 1 4 7 16 

III 68ANC- 116 1.000 21 3 1 

69ANC-97 .970 11 1 2 

69ANC-88 .959 6 1 <0.5 

68ANC-102B .642 1 35 4 10 

IV TT018-10 1.000 1 45 29 2 

TT018-40 .957 7 45 20 6 

68ANC-84 .875 3 23 32 11 

68ANC-156 .859 9 38 6 15 

A Q-mode analysis was run, using 13 nonopaque 

minerals for each of the 100 samples. Four factors 

"explained" 90 percent of the variability displayed 

by the samples (table 2). The fifth eigenvalue constituted only 2 percent of the trace. These factors are 

considered to indicate sediment provenance, although 

the mineralogy of the rocks on the adjacent land is 

poorly known. The mineral assemblages do not 

appear to have been altered by selective removal of 

unstable grains due to weathering. In fact, the heavy 

mineral grains show little evidence of weathering; 

this holds true even for the most easily weathered 

species, such as olivine. Size sorting of minerals may 

have had some effect upon the assemblages. We note, 

for example, an increase in amphibole and pyroxene 

and a decrease in garnet in the 2. 75-4.00 ct> class with 

decreasing median size of the total sand fraction. 

However, comparison of abundances in the 1.0-2.75 

o and 2. 75-4.00 ct> classes suggests that size sorting is 

not a dominant effect, as the mineral composition of 

the two classes is essentially the same in a given 

sample (Venkatarathnam, 1971). Variations in the 

mineralogy of the source rocks that supplied detritus 

to the study area appear to control the heavy-mineral 

variation in the bottom sediments. 

Factor I is thought to represent Yukon River sand. 

Its distribution (fig. 12A) shows high values near the 

Yukon Delta, and there is a similarity between the 

distributions of high Factor I loadings in Norton 

Sound and the 5 <P mode of Yukon silt. The dominant 

components of the factor are clinopyroxenes, rock 

fragments, orthopyroxenes, and amphiboles (table 

2). At this stage in the discussion of the heavymineral factors, there is no implication of geologic 

2 

~ 

1i 

,. -~ ., " 2' ·s "' "' ~ 2' ~ ~ .!;; ~ g ·a ·c ·;s "' :E E ~ e " 0 .D 

c. " " :a 0 " c. 0 

~ s "' "' 0 «: 0: "' :.:: u 

1 1 15 21 1 2 1 

2 2 9 <0.5 20 <0.5 < 0.5 

1 1 4 1 17 <0.5 0.5 

2 2 4 <0.5 20 <0.5 1 

5 1 60 1 8 4 <0.5 5 

4 62 1 4 2 4 

4 51 1 5 1 5 

6 51 1 8 2 4 

1 71 1 2 <0.5 

<0.5 82 4 

1 90 <0.5 1 

1 36 1 11 <0.5 

7 <0.5 6 1 4 <0.5 5 

2 2 4 2 7 <0.5 1 

5 <0.5 11 2 11 1 <0.5 1 

3 1 8 3 11 <0.5 1 3 

time, only of provenance. Whether or not the areas of 

high loadings of this and other factors are now 

receiving sediments of the inferred provenance will 

be discussed later. 

Although Factor II is expressed most strongly by 

garnet, and thus might appear to be monomineralic 

(table 2), comparison with the other factors suggests 

that the epidote, staurolite, chloritoid, and sphene 

are significant. Accordingly, the factor appears to be 

formed of metamorphic minerals, and the distribution (fig. 12B) indicates the source area to be the 

metamorphic rocks of southwestern Seward Peninsula. The factor is mainly developed within and 

inshore from the depression along the coast near 

Nome and in the Cape Rodney Parallel Valley Area 

just to the west. The role of this and other factors 

amid the Point Spencer Shoal Area requires detailed 

study. 

Factor III consists of olivine and clinopyroxene 

derived from the Quaternary olivine basalts (table 2) 

and can easily be correlated with volcanic rocks in 

the adjoining land area (fig. 12C). 

As Factor IV is the final factor, its distribution (fig. 

12D) may reflect a complementary element to the 

sum of the other factors. The multimineral composition of the factor enhances this possibility. This does 

not, however, appear to be the most probable interpretation. 

Factor IV consists of clinopyroxene, amphibole, 

rock fragments, and epidote, a suite that appears to 

be derived from the Jurassic and Cretaceous volcanic rocks and the associated acidic plutons of the 

Okhotsk volcanic belt. The Okhotsk volcanic belt 

encompasses the southern half of Chukotka Penin-
172' 170' 168' 166' 164' 162' 172° 170° 168° 166° 164° 162° 

A B 

65° 65° 

64' 64' 64° 

63' 63° ISLAND 63° 

0 20 40 MILES 0 20 40 MILES 

WH WH 0 20 40 60 KILOMETE RS 0 20 40 60 KILOMETERS 

172° 170° 168° 166° 164° 162° 172° 170° 168° 166° 164° 162° 

65° 65° 

64' 64' 

63° 63° 

172° 170° 166° 164° 162° 

FIGURE 12.-Distribution (percent) of factors from Q-mode factor analysis of heavy minerals in the 2.75-4.00 cfJ class. A, Factor I. B, Factor II. C, Factor III. D, Factor IV. 

t:l 

....... 

U1 

>-3 

~ ttl 

c:: 

>-3 

....... 

0 

z 

0 

'Tj 

ttl 

0 

~ 0 

~ 

U1 

trl 

t:l 

E2 

trl 

~ U1 

0 

z 

>-3 

:I: 

trl 

0 

0 

z 

>-3 

z 

trl 

z 

;; 

t""' 

U1 

:I: 

trl 

t""' 

_'Tl 

z 

0 

:::0 

>-3 

:I: 

trl 

:::0 

z 

ttl 

trl 

~ 

z 

0 

U1 

trl 

> 

0 

...... 

~ 
C20 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

sula and areas farther west in Siberia (Tilman and 

others, 1969), extends southeastward beneath Anadyr Strait and across southwestern St. Lawrence 

Island, thence eastward south of the central and 

eastern part of the island (Patton and Csejtey, 1971; 

Scholl and Marlow, 1970; Nelson and others, 1974). 

Patton (1971) suggests that east of St. Lawrence 

Island, the Okhotsk volcanic belt swings northeastward, passing beneath Norton Sound to connect 

with a north-trending volcanic complex of similar 

lithology and age in the hills of southeastern Seward 

Peninsula. 

Bottom sediments with high values for Factor IV 

cover the bottom in the western part of Bering Strait 

and extend from there southward through western 

Chirikov Basin and the Anadyr Strait. The principal 

minerals of Factor IV dominate heavy-mineral assemblages in bottom samples collected south of 

Anadyr Strait and along the southern Chukotka 

coast, where the order of abundance is: rock fragments, amphibole, clinopyroxene, and epidote (Lisitsyn, 1966). The Factor IV sediments are thus distributed across the sea bottom in areas adjoining 

coasts where the Okhotsk volcanic belt is exposed. 

These sediments are derived in part from submarine 

outcrops, but much of the area in which they occur is 

underlain by the drift of glaciers that originated on 

Chukotka (Nelson and Hopkins, 1972; D. M. Hopkins, C. H. Nelson, and R. B. Perry, unpub. data, 

1973). Factor IV is also strongly developed in bottom 

sediments in northeastern Norton Sound, near the 

late Mesozoic volcanic and plutonic rocks exposed on 

southeastern Seward Peninsula. 

One method of better evaluating the relations 

among the factors is to consider only that part of 

each factor distribution having loading values greater than 0.5. By this criterion five main heavy-mineral 

provinces can be identified (fig. 13). To prevent 

confusion with physiographic provinces, the heavymineral provinces will be referred to as h-m 

provinces. 

The Yukon h-m province extends from the delta 

across Shpanberg Strait to the depression along the 

end of the St. Lawrence Island. Along the northern 

margin of the province, the Yukon sediment is mixed 

with that of the adjacent provinces, particularly in 

Norton Sound. Factor IV sediment can be divided 

into southeastern Seward Peninsula and Chukotka 

h-m provinces on the basis of the plagioclase/Kfeldspar ratio (fig. 11), which is greater than 1 in the 

southeastern Seward Peninsula province. The southeastern Seward Peninsula sediment occupies the 

shoal in Norton Sound, and very similar sediment 

occurs in patches in the eastern part of Shpanberg 

Strait. 

The southwestern Seward metamorphic h-m province is confined to the area of parallel-relief topography between N orne and Bering Strait. The remainder of the Chirikov Basin is dominated by the 

Chukotka h-m province. Several small Quaternary 

olivine basalt provinces are shown in figure 13. 

Scrutiny of the detailed data indicates that several 

other small provinces can be distinguished off each 

end of St. Lawrence Island and near Cape Prince of 

Wales (Venkatarathnam, 1971), butnoneoftheseare 

recorded by the factor analysis, and they are not 

distinguished in figure 13. Venkatarathnam (1971) 

notes that the sediment in an area north of easternmost St. Lawrence Island has a somewhat mixed 

assemblage not recorded by the factor analysis. 

More obvious mixtures of provinces can be noted in 

figure 12, where samples have loadings > 0.5 for 

more than one factor. 

SEDIMENT TYPES 

The data on the mineralogy of the fine sand, 

particularly as summarized by figure 13, and the 

pebble lithology provide a basis for interpreting the 

provenance of the sediments studied. To interpret the 

sediment processes, however, requires knowledge of 

the sediment texture. Although the texture has been 

discussed in terms of gravel, silt, clay, and sand, no 

summary of the textural data has been presented. To 

provide this information, an R-mode factor analysis 

(Dixon, 1970) was run, using as variables the percent 

sediment in each 1/2-¢ or 1-<1> class. The two class 

intervals were used to emphasize the sand sizes 

dominating the sediment in the Chirikov Basin. The 

five factors are considered to be driven by those 

variables having a loading greater than about 0.4 

(table 3). Two of the factors are simple, representing 

silt-clay (Factor I) and fine gravel (Factor III). The 

TABLE 3.- R-mode factor analysis of sediment size. Factor loadings> +0.4 

[Five factors "explained" 74 percent of the variability] 

Phi sizes 

Factor -5 -4 -3 -2 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5 6 7 8 9 10 11 12 

I . 0.43 0.86 0.96 0.94 0.93 0.89 0.80 0.85 

II 0.71 0.85 0.90 0.87 0.75 -0.50 

III . -0.77 -0.91 -0.83 -0.81 

IV . 0.68 0.75 -0.51 -0.67 -0.47 

v ................................... 0.70 0.73 ·0.49 
17 3" 167" 166" 

65° 

63 

0 10 20 30 MILES I I I I I 'I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS I N METERS 

1720 

166" 

165" 640 163" 162" 

EXPLANATION 

Southwestern .S~war d met amo.rphi c prov ince 

Quaternary o hvme basa lt provm ces 

Chuko tka province I 

Yuko n p rovin ce 

So utheastern Seward Peni nsul a prov in ce 

Affinit ies un cert ain 

163" 

61° 

l 

65" 

FIGURE 13.-Heavy-mineral provinces determined on the basis of loading values >0.5 for Q-mode factor analysis. Severa l local provinces not detected by factor analysis 

and not shown are defined by Venkatarathnam (1971). Note mixtures of provinces in areas where loading of> 0.5 occurs for more than one factor. 

I::) 

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...... 
C22 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

TABLE 4.-Values of the 24 variables for extremal samples of each factor in Q-mode factor analysis of sediment size 

Phi size 

Factor Sample li:o. -5 -4 -3 -2 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5 6 7 8 9 10 11 12 

I .. 68 ANC 152 0 0 0 0 0 0 0.03 0.02 0.02 0.04 0.06 0.17 0.51 2.95 50.49 29.34 10.49 0.68 0.74 1.02 0.23 1.16 0.45 1.60 

NW 261-42 0 0 0 0 0 0 .04 .13 .31 .42 .45 .42 .82 24.40 44.68 12.74 6.96 2.88 1.92 .72 1.44 .72 .48 .48 

II. AWF365 0 0 0 0 .20 0 .03 .09 .09 .17 .37 .61 1.12 1.33 1.70 4.19 49.38 17.20 6.45 3.88 3.48 3.30 2.43 3.98 

68 ANC 231 0 0 0 0 .81 .35 .11 .35 .27 .43 .36 .25 .13 .68 4.54 6.37 35.40 19.83 9.23 4.23 3.48 3.93 3.19 6.06 

NW 261-9 0 0 0 0 0 0 0 .04 .04 .04 .04 .67 .75 1.02 2.04 7.47 35.11 19.63 12.47 6.10 3.18 3.98 3.45 3.98 

III . 68 ANC 112 0 0 0 0 .67 .81 1.63 2.31 4.67 11.46 26.61 32.37 15.52 2.54 .30 .06 .27 .80 0 0 0 0 0 0 

TT019-31 0 0 0 0 0 .37 8.06 10.15 12.26 18.78 15.18 16.04 9.14 5.91 2.11 1.56 .37 .06 0 0 0 0 0 0 

IV 68 ANC 94 0 35.91 41.30 9.85 2.90 1.47 .59 .40 .25 .64 

68 ANC 243 14.91 7.92 20.43 18.74 8.07 3.72 3.16 2.23 2.18 1.92 

TT019-29 0 .95 36.50 27.14 8.08 4.90 4.79 3.55 3.37 2.56 

v 69 ANC 112 0 0 0 0 0 .16 .16 .01 .04 

TT018-26 0 0 0 0 0 0 0 0 0 

other three factors are bipolar; that is, they consist of 

high loadings that are positive and negative. This 

complementary arrangement of high positive and 

negative loadings might be produced by geologic 

processes, closure of the closed-number system, or 

other causes. The effect of closure was evaluated, 

using the technique of Kelley (1971); at the 95 percent 

confidence level, it can be shown that the bipolarity 

is not due solely to closure. Consequently, it is 

assumed that this bipolarity is geologically significant-for example, that in Factor IV the 2.0 and 2.5<jl 

sediments respond differently thlm the 3.5-4.0, and 5 

rp sediments. 

To portray the areal distribution of the sediment 

types, a Q-mode analysis was run of the percent 

sediment in each class size. Five factors "explained" 

about 82 percent of the variability. The data for the 

extreme samples are shown in table 4. The distributions plotted in figure 14 represent the sediment 

types in the same manner heavy-mineral factor 

distributions are plotted in figure 13, on the basis of 

loading values greater than 0.5. 

DISCUSSION 

PRESENT-DAY PROCESSES OF SEDIMENT TRANSPORT 

Until in situ measurements are sufficient to determine the exact nature of the processes of sediment 

transport, such processes can be discussed only in a 

highly general descriptive fashion. The only measurements of water motion directly applicable to 

sediment transport have been those made by R. W. 

Sternberg within 1 m of the bottom in the Modified 

Shelf Water of the Chirikov Basin (4-16 em/sec in 

34.5 m water depth) and in the Alaskan Coastal 

Water just north of Bering Strait (25-35 em/sec in 33 

m water depth) (R. W. Sternberg, written commun., 

1971). Comparison of these values with current 

velocities measured in the water column by many 

workers during the ice-free season of several years 

(fig. 3) suggests that a velocity of 30-40 em/sec 

within a meter of the bottom might be representative 

of the coastal water along the Seward Peninsula 

.12 

0 

1.17 .36 .32 .39 .70 .88 .76 .15 .08 .18 .20 .06 .18 1.46 

2.46 2.20 2.34 2.21 .63 .35 1.22 .82 .90 .89 .81 .65 .53 .69 

1.70 .94 .41 .96 .56 .36 .86 .60 .48 .32 .21 .22 .07 .46 

.23 4.92 23.98 55.21 8.40 1.75 2.24 .51 0 .49 .19 .21 .07 1.30 

.92 4.32 41.08 38.11 5.79 1.27 1.51 .39 .43 .40 .55 .46 .82 3.95 

coast, 5-15 em/sec representative of the Chirikov 

Basin, and 2 em/sec representative of the Chukotka 

Trough. 

Assuming that 1 m from the bottom the Alaskan 

Coastal Water moves at a velocity of 30-40 em/sec 

and the Modified Shelf Water at a velocity of 5-15 

em/sec, then comparison can be made with one of 

various "competency curves" for sediment transport, 

that of Sundborg (1956). Sternberg (1971) concluded 

from in situ measurements that these curves adequately predicted sediment motion in some marine 

environments for certain size particles. Assuming 

that the curves are adequate for our study area, then 

all the modal sediment sizes underlying the coastal 

water except the gravel (fig. 9) should be subject to 

bedload transport, and some erosion would even be 

expected. However, little or no bedload transport of 

fine and medium sand would be expected beneath the 

Modified Shelf Water, an interpretation that is supported by the absence ofbed-roughness elements in a 

time-series of bottom photographs made by R. W. 

Sternberg (written commun., 1971). On the other 

hand, bottom currents seem to be adequate to move 

very fine sand, silt, and clay-sized particles everywhere in our study area except in the Chukotka 

Trough, and much of the transport should be as 

suspended load. The modal size of the suspended 

sediment samples by McManus and Smyth (1970) is 

20 )1m. 

The in situ temperature and salinity of highlatitude seas can significantly lessen the settling 

velocity of a sediment particle with attendant effects 

on the sediment movement. If one inserts into a 

settling-velocity equation such as Waddell's (Krumbein and Pettijohn, 1938, p. 104) the approximate 

average conditions of the coastal water (10°C, 

32° /oo), the Modified Shelf Water (1 °C, 32.5° /oo), 

and the Deep Shelf Water representing winter conditions (-1.75°C, 32.5° /oo), the settling velocity is 

only 81, 76, and 72 percent, respectively, of that for 

standard conditions. The increased viscosity of the 

cold water, therefore, means that a particle in suspension settles with a smaller effective diameter 
!73" 172" 

65··--

64",--

63"~-

'i 20 30 MILES 

I ' 'I I I Jo Jo KILOMETERs 0 10 20 

171° 168° 167° 166° 

l

- o tO I 1 

ISOBATHS '"METERS ' I i I I I -----1_______ ___ __1_ ____ ---l___ I I 

172• 171° 169• ·---

167° 166° 

165° 

165° 

164° 163° 

164° 

EXPLANATION 

Very fine sand 

Silt 

Medium sand 

Gravel 

Fine sand 

163° 

162° 161" 

65° 

64° 

FIGURE 14.-Sediment types determined on the basis of loading values> 0.5 for Q-mode factor analysis. Data for "extreme" samples for each type are presented in table 5. 

Note mixtures of sediment types. 

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1-1 

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ljj 

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CJJ 
C24 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

than, under standard conditions and, other things 

being constant, may be more easily transported. 

The current measurements near the bottom and in 

the water column represent many types of motion. 

Swift, Stanley, and Curray (1971) classify the water 

motions on a continental shelf as (1) intruding 

oceanic currents, (2) tidal currents, (3) meteorological 

currents, and (4) density currents. The most pronounced current in the study area is the northward 

flow resulting from the slope of the sea surface, 

which presumably falls into the class of intruding 

oceanic current. Its dominance is manifest in the 

lack of a net reversal lasting more than a few days. 

The role of tidal currents in the study area is uncertain. At least two waves of semidiurnal period are 

known, and the number may exceed five (K. Aagaard, written commun., 1970). Two of the several 

sources of complexities in interpreting these longperiod waves are the similarity in period of certain 

tidal species and inertial waves at this latitude and 

the considerable wave reflection that occurs. From 

the current m~asurements, it appears that the velocity of the long-period waves is o£ the same order of 

magnitude as that of the average current through the 

region, tens of centimeters per second (K. Aagaard, 

written commun., 1970). Under certain conditions, 

then, the tidal currents might double the speed of the 

water movement, thereby significantly increasing 

sediment transport, and possibly initiating erosion. 

Such transport would be in a generally "northward" 

direction. Under opposite conditions, in opposition to 

the average northward-setting current, the water 

movement may be almost stopped, and sediment 

transport may be greatly reduced. 

Few measurements have been made that pertain to 

meteorological currents. Even the wind measurements are from land stations whose records may be 

biased by local topography. Assuming that these 

wind speeds are representative and that over 60-90 

percent of the year the winds are 1-16 knots (U.S. 

Coast and Geodetic Survey, 1964), and assuming 

reasonable fetch lengths and wind durations, then 

the deepwater wave characteristics can be calculated, using the method of the U.S. [Army] Beach 

Erosion Board (1961, p. 16a). From the equation of 

the maximum horizontal orbital velocity of water 

particles at the bottom (Shepard, 1963, p. 61), it 

appears that waves are effective in initiating sediment motion to an average depth of about 20m, and 

to greater depths during storms. A residual current 

or wave drift might thus play a critiGal role in water 

less than 20 m depth, but probably not in the deeper 

water. 

Another type of meteorological current is the wind 

setup. In the study area, this effect is most evident 

along the southern coast of Seward Peninsula, where 

sea level may rise as much as 4 m and remain at that 

level for a short period (U.S. Coast and Geodetic 

Survey, 1964). This rise or setup results from strong 

southerly winds and is particularly effective here, 

because it is not only proportional to the shear stress 

on the water but is inversely proportional to water 

depth (Wiegel, 1964). Consequently, over the very 

shallow shelf of northern Bering Sea, the importance 

of decreasing water depth to the wind setup is greater 

than usual. The water with its contained sediment 

piled up against the Seward Peninsula coast must 

later be removed to the north, as part of the net flow 

of water toward Bering Strait. 

Of the meteorological currents, the most critical in 

the study area is probably the wind-driven current, 

as wind-driven currents, or wind drift, can be effective in transporting sediment if the water depth is 

less than the depth of frictional resistance. If 10 

knots is a reasonable estimate of a common wind 

velocity here (U.S. Coast and Geodetic Survey, 1964), 

the depth of frictional resistance can be computed as 

80 m (Sverdrup and others, 1942, p. 494), meaning 

that wind-generated currents probably produce a 

frictional effect on the bottom throughout the study 

area. The extent to which this effect would be 

recorded by the current measurements is unknown, 

however. Locally, the wind can reverse the northward-setting current and produce southerly water 

transport for a short time (Husby, 1971). 

The density currents in the classification of Swift, 

Stanley, and Curray (1971) probably are not effective 

in the study area because the shallow depth permits 

mixing throughout much of the water column, thereby breaking down stratification, and because of the 

intensity of the other processes. 

A range of conditions is apparent from this discussion, but the greater intensity of processes in the 

coastal water, particularly along the Seward Peninsula coast, is clear. The northward transport of water 

everywhere except in Norton Sound should be reflected in the present-day distribution of sediment. 

SEDIMENT DISPERSAL 

Bottom sediments may be classified as modern, 

relict, or palimpsest (Emery, 1952; Swift and others, 

1971). In the Bering Sea, modern sediments are those 

that consist of material recently introduced into the 

marine environment and dispersed by present-day 

currents. Relict sediments consist entirely of material introduced into the sea at some time in the past. 
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C25 

Palimpsest sediments are a mixture of modern and 

relict sediments. Recognition of these different types 

of sediment is commonly facilitated by a study of 

their biogenic components, as the relict sediment 

may contain a relict fa una or other evidence of age. 

R. E. Echols (written commun., 1971) examined 

Foraminifera in the surface layers of many samples 

of sediment that we believe on the basis of sedimentological inference to be relict. The fauna consists chiefly of benthic arenaceous forms and seems 

to be entirely derived from the thriving living population. Relict tests, if present, are completely masked by modern ones. As a result of the relict arenaceous tests being destroyed, removed, or reworked 

downward into the sediment, the benthic Foraminifera cannot be used to differentiate relict from 

modern sediment. 

The modern sediments most easily identified in the 

study area are the silts of southern Norton Sound. 

Their location near the Yukon Delta, the dominance 

of silt in the rivers in this climate (Taber, 1943; 

Lamar, 1966), and the mineralogy of the associated 

sand suggest a Yukon origin. Moreover, the distribution pattern of the deposit to the north and 

northwest of the delta can be related to the northwest-setting coastal water, part of which must enter 

Norton Sound. Although part of the silt may be 

derived from south of the study area and may be 

carried into the area in the coastal water (McManus 

and Smyth, 1970), the Factor Ilsedimentofsouthern 

and central Norton Sound is thought to consist 

mostly of modern Yukon silt (fig. 14). 

The R-mode factor analysis of phi sizes suggests 

that the 3.5, 4.0, and 5 </>classes might be geologically 

related to one another. Accordingly, if the 5 <J> sediment in southern Norton Sound is modern Yukon 

silt, then possibly the Factor I sand west of the silt 

(fig. 14) representing 3.5 ¢and 4.0 ¢sand is modern 

Yukon or Alaskan Coastal Water sand. The mineralogy of the Factor I sand (I) is the same as that of the 

sand in the adjacent Yukon silt area (II), implying 

the same origin (fig. 13). There is an apparent textural gradation in a "downstream" direction into 

Norton Sound from sand (1), through mixed sand 

and silt (I and II), into silt (II) inside the sound (fig. 

14). Finally, the modern age of this very fine sand (I) 

is suggested by the good sorting (fig. 10). The west 

edge of this sand coincides approximately with the 

western margin of the Alaskan Coastal Water. The 

northward velocities of 30-40 em/sec in this water 

(McManus and Smyth, 1970) are competent to transport this very fine sand from the main mouth of the 

Yukon River near the south edge of our area or from 

farther south. In the process, a smooth topography is 

being formed. 

The sands underlying the Shpanberg Strait have 

the same mineral assemblage as these very fine 

sands (fig. 13). The fine sands in the strait (Factor V, 

fig. 14) ·are coarser, however, and are formed into 

ridges and depressions. As the low current velocities 

(10 em/sec) of the Modified Coastal Water in the 

strait (McManus and Smyth, 1970) are incapable of 

transporting this fine sand, presumably it is relict 

from a time of lowered sea level when the Yukon 

River extended farther southwest. 

The ridges and depressions in Shpanberg Strait 

are probably relict. The modern current regime there 

does not appear capable of constructing topography 

of this sort, although it may be adequate to preserve 

it. The westernmost depression may be a graben 

(Grim and McManus, 1970) or a drowned stream 

valley (D. M. Hopkins, C. H. Nelson, and R. B. Perry, 

unpub. data, 1970). The other ridges probably were 

built in shallow water early in the Holocene transgression. A sampling transect across a ridge that 

crests at about 20 m shows that sand on the summit 

is finer than sand on the flanks; if the sediments in 

the ridge were affected by some present-day process 

such as wave-stirring, one would expect to find the 

coarsest sediment on the ridge crest. 'J'he summit 

sand is brown and richer in heavy minerals than the 

sand on the flanks, suggesting that it has been 

affected by shoreline processes, probably during the 

20m stillstand that produced shoreline deposits off 

Nome (Nelson and Hopkins, 1972)andPointSpencer 

(Hopkins, 1967). 

The main effect of the topography upon modern 

processes in Shpanberg Strait appears to be a localization of silt deposition in the eastern depression 

(fig. 6). Nearer the delta, there is a zone in which the 

relict fine sand (V in fig. 14) seems to be mixed with 

encroaching modern very fine Yukon sand (I, fig. 14), 

producing a palimpsest sand (1-V, fig. 14). 

The Yukon heavy-mineral association characterizes the relict sand in Shpanberg Strait (V), the 

modern very fine sand to the east (1), and the sand 

fraction in the silts of southern Norton Sound (II). In 

northern Norton Sound, however, the sand fraction 

in the presumed Yukon silt is a mixture of Yukon and 

southeastern Seward Peninsula associations (fig. 

13). This mixture indicates either a mixture of modern sediments from two sources or a spreading of 

Yukon sandy silt over relict southeastern Seward 

Peninsula sand. The second interpretation is preferred for the following reasons: (1) where the southeastern Seward Peninsula mineral assemblage is the 
C26 STUDIES ON THE MARINE GEOLOGY OF THE BERING SEA 

sole compositional type, the sediment is not silt but 

sand (Factor V, 2.5 and 3.0 </>, fig. 14), and (2) this 

sand (V) is associated with shoals that do not appear 

to be modern topographic forms and that are probably prevented by wave action from being covered 

with finer (and modern) sediment. Bioturbation may 

play some role in the mixing of sediment types. 

If the sediments in Norton sound that bear the 

southeastern Seward Peninsula mineral association 

are largely relict, then there must be only a thin 

accumulation of Yukon sandy silt there. This inference is supported by box cores in central Norton 

Sound that show as little as 20 em of Holocene sandy 

silt overlying subaerial peaty silt or sand (Nelson 

and others, 1975) and by the low quantities of 

suspended sediment observed in central Norton 

Sound by Sharma and others (1974). Consequently, 

much of the modern Yukon sandy silt observed 

entering Norton Sound along the southern side must 

leave it along the northern side, possibly along the 

pathway marked by the silt distribution in the 

depression extending from near Golovnin Bay westward past Nome (fig. 2; fig. 14, Factor II). The silt 

continues northwest of Sledge Island toward King 

Island (fig. 6). Suspended-sediment measurements 

by McManus and Smyth (1970) off Nome and in 

Norton Sound showed that the silt was in suspension 

in the bottom water and that the bottom water 

apparently was flushed periodically from northern 

Norton Sound. The silt extending through the 

depression and thence northwestward toward King 

Island is therefore not viewed as a rapidly thickening and laterally expanding blanket of Yukon detritus burying the other sediments but as material 

temporarily stored, later to be resuspended and 

moved through this part of the study area by the 

Alaskan Coastal Water and associated outflow from 

Norton Sound. Similarly, the northern terminus of 

the silt near King Island is probably a dynamic 

boundary related to increasing current velocities 

approaching the constriction of Bering Strait. 

Heavy-mineral analysis of the 2.75-4.00 </> sand 

fraction from the body of silt between Nome and 

King Island shows a southwestern Seward Peninsula metamorphic association (fig. 13). Consequently, although the coastal water is transporting 

Yukon silt through the area, the silt is passing over, 

and being mixed with, sand that is probablyofrather 

local .origin. According to Nelson and Hopkins 

(1972), glacial material from the metamorphic 

terrane on land or from submarine outcrops must be 

near the surface of the Cape Rodney Parallel Valley 

Area. This interpretation is supported by the gravel 

lithology, by the high content of heavy minerals, and 

by the metamorphic heavy-mineral assemblage. 

Apparently, the strong northward-setting current 

has prevented the glacial or bedrock metamorphic 

material from being buried by the Yukon sediment. 

The result is a coarse-grained relict sand and gravel 

that has been made into a lag deposit forming the 

Cape Rodney Parallel Valley topography beneath 

the strong current of the Alaskan Coastal Water. 

Where the modern Yukon silt is mixed with relict 

sand, a palimpsest sediment is being formed. 

Studies of bottom sediments in the Chukchi Sea 

indicate that the Yukon silt continues moving northward through Bering Strait (McManus and others, 

1969). The silt being transported along the western 

flank of Prince of Wales Shoal was studied by 

McManus and Creager (1963) and was recently 

analyzed in relation to current measurements within 

1m of the bottom (R. W. Sternberg, writtencommun., 

1971). The relict coarse sand and gravel in the strait, 

whether from bedrock or till, have been formed into a 

lag sediment by the scouring action of the current 

through the strait. The rest of the gravel deposits in 

the Chirikov Basin-for example, those north and 

north west of St. Lawrence Island- appear to be 

moraines or winnowed moraines. 

The sediment covering Gambell Shoal is assumed 

to be relict because it consists of poorly sorted coarse 

sand of mineralogy similar to nearby relict gravel 

derived from Chukotka; there is no modern source 

introducing coarse sand in this area. A relict beach 

deposit, formed when sea level was lower, is found at 

depths of 36-38 m on the western flank of Gambell 

Shoal. It consists of brown well-rounded sand and 

gravel and weathered shell fragments. 

Except at the margins of Gam bell Shoal, the sands 

of the Chirikov Ramp are either fine sand (V, fig. 14) 

or very fine sand (I). Both have a Chukotka association of heavy minerals, light minerals, and clay 

minerals. The fine sand (V) occupies most of the 

Chirikov Ramp. As there appears to be little chance 

of this sediment coming from Ch ukotka at present, it 

is assumed to be relict. To the northeast, this fine 

sand derived from Ch ukotka (V) gives way to sand 

with a southwest Seward Peninsula heavy-mineral 

assemblage (III). The change in heavy-mineral associations is along the boundary between the Chirikov 

Ramp and the Cape Rodney Parallel Valley Area. 

This change in topography, sediment texture, and 

heavy-mineral composition is best correlated with 

the average location of the boundary between the 

Alaskan Coastal Water and Modified Shelf Water. 

The coastal water, where currents are stronger, 

overlies the parallel ridges and swales mantled by 

the southwest Seward Peninsula medium sand, and 
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C27 

the Modified Shelf Water overlies the finer Chukotka 

sediment in which the subdued topography of the 

Chirikov Ramp is developed. Although there is a 

gradation of sediment texture across the bounda~ 

from one topographic province to the other, there Is 

no mixing of heavy-mineral associations (fig. 13). 

The poorly sorted very fine sand (I) in the flat 

bottom of the Chukotka Trough is considered to be 

relict because of the low current velocities there. 

Farther north, the current speed has to increase, and 

this may be reflected by the change to a coarser 

grained sand despite increased depth of the trough. 

The nature of the low ridge in the Norton Plain 

north of eastern St. Lawrence Island is enigmatic. 

The sediment texture, topography, and geometry 

suggest that the ridge is a modern feature with a 

cover of modern sediment. Yet the heavy-mineral, 

light-mineral, and clay-mineral assemblages and 

the physical oceanography suggest that the surface 

feature and the sediment are relict. No determination 

can be made at this time. 

The Yukon sand, whether modern or relict, cannot 

be recognized northwest of a line from the eastern tip 

of St. Lawrence Island to Sledge Island. We considered three possible explanations for the absence 

of Yukon sand from the Chirikov Basin: (1) The 

Yukon sand may have been once present, but subsequently flushed out of the Chirikov Basin by strong 

bottom currents. This seems unlikely, because the 

areas that lack Yukon sand are characterized by 

relatively weak bottom currents. (2) The Yukon sand 

may be younger than the relict sediment of the 

Chirikov Basin and may have advanced north westward only to its present boundary along a line 

extending from eastern St. Lawrence Island to King 

Island. If this proves to be so, it will imply that the 

mouth of the Yukon River has been located in its 

present position for only a short time and that the 

river previously entered the sea farther south. (3) The 

boundary that we have drawn between the Yukon 

and the Chukotka sands may be artificial, merely 

reflecting increasing difficulty in distinguishing the 

two heavy-mineral associations with increasing distance of transport. Further knowledge of the sediments of the Chirikov Basin will be required before 

we can choose between the last two of these possible 

explanations. 

The second explanation seems to be the better, 

because recent studies indicate that the mouth of the 

Yukon River lay 80 to 160 km south of its present 

position during early Holocene time. Displacem~nt 

of the outlet to its present position occurred no ear her 

than 6,200 years ago (Nelson and Creager, 1977) and 

possibly as recently as 1,200 years ago (Dupre, 1977). 

SUMMARY AND CONCLUSIONS 

Study of the bottom sediments ~n the no~thern 

Bering Sea has provided information on sediment 

texture as it relates to sedimentary processes and on 

sand mineralogy and pebble lithology as they relate 

to provenance and relative age of the ~edimen~s. 

From this information, we can map sediment distribution and tentatively define ancient and modern 

path ways of dispersal (fig. 15). 

The largest area covered by modern sediment is 

adjacent to the Yukon delta in. s~uthern .Nort:on 

Sound. Here the sediment is pnncipally silt With 

some very fine sand and clay-sized rna terial. The distribution pattern is controlled by the northwardsetting Alaskan Coastal Water and the Yukon runoff but the exact effects of these currents and other 

pr~cesses acting upon the sediment have not been 

measured. The part of the coastal current that 

crosses the mouth of Norton Sound has higher 

velocities than the part entering the cui de sac. 

Correlative with this, the coarser part of the modern 

Yukon sediment lies across the mouth of the sound, 

the finer rna terial inside. The coarsest modern 

Yukon sediment is a very fine sand. Along its 

western boundary, this modern sand is being mixed 

with a coarser relict Yukon sand to form a palimpsest 

sediment (1 in fig. 15).5 

The Yukon silt covers much of Norton Sound. 

Except near the delta, however, the silt deposit 

appears to be relatively thin. If, as suggested by 

Lisitsyn (1966), the Yukon River supplies 90 percent 

of the sediment entering the Bering Sea, then the 

accumulation rate (depositional rate less resuspension rate) must be low, although it has not been 

measured. The presence of a large area of relict sand 

in Norton Sound suggests that velocities of wave and 

wind drift, tidal currents, and flow associated with 

the coastal water are intense enough to keep in 

suspension much of the silt and to flush it from the 

sound into the main part of the coastal current. At 

times, some of the silt moves directly across the 

mouth of Norton Sound (Hooper, 1884, p. 20; Sharma 

and others, 1974; Nelson and others, 1975) an~ does 

not enter the sound at all. Part of the sediment 

appears to pass through Norton Sou?-d, ~hen e.xit 

through a depression on the north side In whiCh 

Yukon silt forms modern and palimpsest deposits. 

s It should be noted that an alternative explanation for the origin oft~~ very fine sa?d 

is that at the present time it is being formed into a deposit by the un~nnng of the rehct 

sand. The relict sand, instead of the Yukon River, would be the proXImate source of the 

very fine sand. This is thought to be an unlikely explanation, however, ~a use the ~ery 

fine sand appears to be associated with the coastal water that has velocities appropnate 

for it.s transport. An extended series of measurements on transport of the very fine sand 

is needed. 
65' ,. __ 

64" 

173" 1-!2.., 171' 

0 10 20 30 MILES I I I I I I I I I I 0 10 20 30 40 KILOMETERS 

ISOBATHS IN METERS 

BERING STRAI:;:-~--- .' 'Ioo 50[ -4o ~-;y-~·· ----·· 167" .-- 166' . lf 1!11. 50 .· .IO. · ... ·· . . ---------·--·- 1_ c 

. I. . . ..· .... ··.. I --· " 

170' 169" 168° 162' 161° 

.·.d.. 't;;r) / YUKON SILT --T--·--'14'- - 163' 

\>· ·. · · MODE S'-.. ,_._ ... C . f RN IF""li EXPLANATI 

. ~ ..... A PALIMPSEST lb...d! Modern Yukon very ON fine sand and relict Yukon fine sand 

Modern Yukon silt and relict southeastern 

-;-.. ·..,.-.......· 60 

A·" ·.A·.·. •• ' 0 • • 

~ :<·_ ... · 

169' 168' 167" 166' 165' 

Seward Peninsula and Yukon sands 

Modern Yukon silt and relict southwestern 

Seward Peninsula metamorphic sand 

Modern and relict St. Lawrence Island sands 

Quaternary olivine basalt sand and gravel 

Chukotka - St. Lawrence Island glacial gravels 

Bering Strait gravel 

Southwestern Seward Peninsula metamorphic sand and gravel 

164° !63' 162' 

i 

I 

J65' 

I ! I 

NORT I 8 

-~;· 

·• 63' 

FIGURE 15.-Bottom-sediment distribution from McManus, Venkatarathnam, Hopkins, and Nelson (1974). Relict sediments may include residual material. 

0 

t-.:) 

00 

00 

~ 

c::: 

t::l 

....... 

t_:l:j 

00 

0 

z 

~ 

:I: 

t_:l:j 

s:: 

> ::0 

z 

t_:l:j 

0 

t_:l:j 

0 

~ 

0 

0 

>< 

0 

"%j 

~ 

:I: 

t_:l:j 

to 

t_:l:j 

::0 

z 

0 

00 

t_:l:j 

> 
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C29 

On a secular scale, the silt in this depression may 

represent a steady-state condition between deposition and erosion. Yukon silt is a component of the 

bottom sediment as far north as the dashed line in 

figure 15, but we do not consider the small percent of 

silt in this relict sand sufficient to classify the sediment as palimpsest. The minor silt component here 

underlies high-speed currents that are probably 

capable of moving most of the modal sands. The silt 

fraction must be a very dynamic part of the bottom 

sediment and certainly does not represent the leading edge of an area of net silt accumulation. Farther 

north, the silt is kept in suspension and forms a high 

concentration where the coastal water is constricted 

by Bering Strait. Silt again becomes the dominant 

sediment size along the western margin of Prince of 

Wales Shoal, which extends into the Chukchi Sea. 

The Yukon silt is clearly the most dynamic sediment in the study area. Yet no measurements of its 

transport are available. What portion is transported 

across the mouth of Norton Sound and what portion 

enters the sound? What is the effectiveness ofresuspension of silt in southern Norton Sound? What is 

the distribution of suspended silt over relict sand 

areas within the sound? What proportion of the silt 

issuing from the sound accumulates in the northern 

depression and what is the residence time of a silt 

particle if the deposit in the depression is in steady 

state? What is the nature of the movement of the silt 

by the high -speed coastal current in the Cape Rodney 

Parallel Valley Area? With answers to these questions, more knowledge of the sedimentary environments would be available for at least the 3-month icefree season. The nature ofsedimenttransportduring 

the ice-covered season is unknown. 

Most of the palimpsest sediment consists of modern Yukon detritus mixed with older sediment, but 

there are two types of palimpsest sediment that 

appear to be unrelated to Yukon sediment. Modern· 

and relict sands near western St. Lawrence Island 

appear to be mixed by some undefined process. The 

modern and relict Quaternary basalt s~nd and 

gravel are indistinguishable and hence are classified 

as palimpsest. Relative to the modern Yukon sediment supply, the modern components of other 

palimpsest sediments is insignificant. 

Relict sediments cover the Chirikov Basin, and 

indeed most of the study area. As neither their 

relative nor their absolute age is known, however, we 

can draw only tenuous inferences about the sedimentologic history. 

In Shpanberg Strait there is a relict fine-grained 

Yukon sand that has been formed into depressions 

and ridges whose crests lie at the level of the 20-m 

shoreline. Along the margins of this area, the sand 

has been mixed with other relict sands at the time of 

deposition or later. The results of a single series of 

near-bottom current measurements indicate that the 

mixing may not be occurring today. These measurements also indicate that the current speeds over the 

relict sand in Shpanberg Strait are sufficient to 

prevent an accumulation on the bottom of the silt 

particles that are passing in suspension. Presumably this condition obtains for the other areas of 

relict sands, but measurements have not been made. 

The relict southwest Seward Peninsula metamorphic sand and gravel (Unit D, fig. 15) lies in a 

region in which currents are probably adequate to 

resuspend the modal-sized sands. The extremely 

poor sorting is produced largely by an admixture of 

Yukon silt. The boundary between the southwest 

Seward Peninsula sand and the Chukotka sand to 

the west is exceptionally sharp; the textural and 

mineralogical boundary coincides with a topographic boundary that probably represents the mean 

position of the western edge of the strong coastal 

current. It seems tha.t the coastal current has left a 

relict·or residual lag deposit in a streamlined topography developed on glacial material or on bedrock. 

Measurements of sediment transport are needed in 

the Cape Rodney Parallel Valley Area to verify this 

hypothesis. 

Relict or residual gravel appears to be derived from 

bedrock, glacial till, or moraines. Most of the gravel 

in the Chirikov Basin is a lag deposit on glacial drift 

derived from Chukotka. Modern ice-rafted pebbles 

form a significant component of the sediment only 

near the shore (Nelson and Hopkins, 1972). 

The relict sediments of the Chirikov Basin contain 

no evidence that Yukon sediment has ever accumulated there nor that the river formerly drained 

through the basin into the Chukchi Sea. The relict 

Yukon sands are found only east of a line from 

eastern St. Lawrence Island to Nome, and the modern Yukon sands are even more restricted in area. 

Either the characteristics of the Yukon sands are 

soon lost during transport on the shelf, or, the mouth 

of the Yukon River has lain in its present northern 

position for only a brief period. Migration of the river 

mouth seems likelier (Knebel and Creager, 1973; 

McManus and others, 1974). 

A sea ward decrease in grain size is commonly 

accepted as a criterion for recognizing a deposit of 

modern, as distinguished from relict, sand-that is, 

of sand being derived from the adjacent shore. The 

westward fining of sediment from the shallow water 

near Seward Peninsula to the relatively deep water 

in the Chukotka Deranged Area might be so inter-
C30 STUDIES 0N THE MARINE GEOLOGY OF THE BERING SEA 

preted, but the sediment is too coarse to be supplied 

from the shore at this time; it is therefore relict rather 

than modern sand. Moreover, the heavy minerals in 

this relict sand are from source rocks in two areas: 

the relict sand in the deeper water was derived from 

Chukotka, that in the shallow water from Seward 

Peninsula. Although the grading in the relict sand 

might have been produced by nearshore processes 

migrating across the area with changes in sea level, 

this does not seem likely because similar size grading 

is not present elsewhere-for example, off St. Lawrence Island. Rather the size grading seems to have 

been produced by the presence, now, of the strong 

'north ward -setting current along south western 

Seward Peninsula. This current would have a bottom 

Ekman effect such as that measured in the Bering 

Strait by Coachman and Aagaard (1966) that would 

result in northward transport along the bottom at a 

small angle to the isobaths and left or seaward 

rather than paralleling the isobaths. By this current, 

the sediment could be transported seaward. Such a 

condition for the con tin ental shelf off Washington is 

described by Smith and Hopkins (1972). The seaward 

decrease in current velocity off Seward Peninsula 

would produce a gradient in transport competency, 

and probably a similar gradient in grain size. Measurements of sediment transport are needed to test 

the hypothesis of producing sea ward fining of relict 

sand by present-day processes. 

REFERENCES CITED 

Blatt, Harvey, 1967, Provenance determinations and recycling of 

sediments: Jour. Sed. Petrology, v. 37, p. 1031-1044. 

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

through Bering Strait: Limnology and Oceanography, v. 11, 

p. 44-59. 

Coachman, L. K., Aagaard, K., and Tripp, R. B., 1975, Bering 

Strait, the regional physical oceanography: Seattle, Univ. 

Washington Press, 186 p. 

Coachman, L. K., and Tripp, R. B., 1970, Currents north of Bering 

Strait in winter: Limnology and Oceanography, v. 15, 

p. 625-632. 

Creager, J. S., and McManus, D. A., 1967, Geology of the floor of 

Bering and Chukchi Seas-American studies, in Hopkins, 

D. M., ed., The Bering land bridge: Stanford, Calif., Stanford 

Univ. Press, p. 7-31. 

Dixon, W. J., 1970, Biomedical computer programs: California 

Univ. Pubs. Automatic Computation 2, 600 p. 

Dupre, W. R., 1977, Yukon Delta coastal processes study, in 

Assessment of the Alaskan Continental Shelf: U.S. Natl. 

Oceanog. Atmospheric Admin. and U.S. Bur. Land Management Principal Investigators Rept. Year ending March 

1977 (in press). 

Emery, K. 0., 1952, Continental shelf sediments of southern 

California: Geol. Soc. America Bull., v. 63, p. 1105-1108. 

Fleming, R. H., and Heggarty, D., 1966, Oceanography of the 

southeastern Chukchi Sea, in Wilimovsky, N.J., and Wolfe, 

J. M., eds., Environment of the Cape Thompson region, 

Alaska: U.S. Atomic Energy Comm., Washington, D.C., 

p. 697-754. 

Folk, R. L., and Ward, W. C., 1957, Brazos River Bar-a study in 

the significance of grain-size parameters: Jour. Sed. Petrology, v. 27, p. 3-26. 

Grim, M. S., and McManus, D. A., 1970, A shallow seismicprofiling survey of the northern Bering Sea: Marine Geology, 

v. 8, p. 293-320. 

Hooper, C. L., 1884, Report of the cruise of the U.S. Revenue 

Steamer Thomas Corwin in the Arctic Ocean, 1881: Washington, D.C., U.S. Govt. Printing Office. 

Hopkins, D. M., 1967, Quaternary marine transgressions in 

Alaska, in Hopkins, D. M., ed., The Bering land bridge: 

Stanford, Calif., Stanford Univ. Press, p. 47-90. 

Hopkins, D. M., Nelson, C. H., and Grim, M. S., 1969, Extent 

of glaciation on the floor of northern Bering Sea [abs.]: Internat. Quaternary Assoc. (INQUA) Cong., 8th, Paris 1969, 

Resumees des Communications, p. 209. 

Hopkins, D. M., Nelson, C. H., Perry, R. B., and Alpha, T. R., 1976, 

Physiographic subdivisions of the Chirikov Basin, northern 

Bering Sea: U.S. Geol. Survey Prof. Paper 759-B, 7 p. 

Hopkins, D. M., Rowland, R. W., and Patton, W. W., Jr., 1972, 

Middle Pleistocene mollusks from St. Lawrence Island and 

their significance for the paleo-oceanography of the Bering 

Sea: Quaternary Research, v. 2, p. 119-134. 

Husby, D. M., 1971, Oceanographic investigations in the northern 

Bering Sea and Bering Strait, June-July 1968: U.S. Coast 

Guard Oceanog. Rept. 40, Washington, D.C., 50 p. 

Imbrie, John, and van Andel, Tj. H., 1964, Vector analysis of 

heavy-mineral data: Geol. Soc. America Bull., v. 75, p. 1131-

1156. 

Kelley, J. C., 1971, Mathematical analysis of point count data, 

in Carver, R. E., ed., Procedures in sedimentary petrology: 

New York, John Wiley, p. 407-425. 

Kelley, J. C., and McManus, D. A., 1969, Optimizing sediment 

sample plans: Marine Geology, v. 7, p. 465-471. 

--1970, Hierarchical analysis of variance of shelf sediment 

texture: Jour. Sed. Petrology, v. 40, p. 1335-1339. 

Knebel, H. J., and Creager, J. S., 1973, Yukon River; evidence for 

extensive migration during the Holocene transgression: Science,v. 179,p. 1230-1232. 

Krumbein, W. C., and Pettijohn F. J., 1938, Manual of sedimentary 

petrography: New York, Appleton-Century-Crofts, 549 p. 

Lamar, W. L.,.1966, Chemical character and sedimentation in the 

waters, in Wilimovsky, N.J., and Wolfe~ J. M., eds., Environment of the Cape Thompson region, Alaska: U.S. Atomic 

Energy Comm., Washington, D. C., p. 138-148. 

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

U.S.S.R. Acad. Sci., Inst. Oceanology (English Translation: 

Israel Program for Scientific Translations), 1969, 614 p. 

Mcintyre, D. B., 1963, Precision and resolution in geochronometry, 

in Albritton, C. C., Jr., ed., The fabric of geology: Palo Alto, 

Calif., Addison-Wesley Pub. Co., p. 112-134. 

McManus, D. A., and Creager, J. S., 1963, Physical and sedimentary environments on a large spit-like shoal: Jour. Geology,v. 71,p.498-512. 

McManus, D. A., Kelley, J. C., and Creager, J. S., 1969, Continental shelf sedimentation in an Arctic environment: Geol. Soc. 

America Bull., v. 80, p. 1961-1983. 

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

the continental shelf of the northern Bering Sea: Jour. Sed. 

Petrology, v. 40, p. 869-873. 

McManus, D. A., Venkatarathnam, Kolla, Hopkins, D. M., and 

Nelson, C. H., 1974, Yukon River sediment of the northern-
DISTRIBUTION OF BOTTOM SEDIMENTS ON THE CONTINENTAL SHELF, NORTHERN BERING SEA C31 

most Bering Sea shelf: Jour. Sed. Petrology, v. 44, p. 1052-

1060. 

Moll, R. F., 1970, Clay mineralogy of the Bering Sea shallows: 

Univ. Southern California Rept. USC-GEOL 70-2, 101 p. 

Nelson, C. H., and Creager, J. S., 1977, Displacement of Yukonderived sediment from Bering Sea to Chukchi Sea during 

Holocene time: Geology, v. 5, p. 141-146. 

Nelson, C. H., and Hopkins, D. M., 1972, Sedimentary processes 

and distribution of particulate gold in the northern Bering 

Sea: U.S. Geol. Survey Prof. Paper 689, 27 p. 

Nelson, C. H., Hopkins, D. M., and Ness, G., 1969, Interpreting 

complex relict and modern sedimentation patterns on the 

Bering shelf: Geol. Soc. America Abs. with Programs 1969, 

v. 1, no. 7, p. 159. 

Nelson, C. H., Hopkins, D. M., and Scholl, D. W., 1974, Tectonic 

setting and Cenozoic sedimentary history of the Bering Sea, 

in Herman, Yvonne, ed., Arctic geology and oceanography: 

New York, Springer-Verlag, p. 119-140. 

Nelson, C. H., Larsen, B. R., and Rowland, R. W., 1975, ERTS 

imagery and dispersal of Yukon and Kuskokwim River 

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

Peterson, D. H., eds., Principal sources and dispersal patterns 

of suspended particulate matter in nearshore surface waters 

of the northeastern Pacific Ocean; ERTS Final Report: Natl. 

Tech. Inf. Service Rept., U.S. Dept. Commerce, E-75-10266, 

p. 26-40. 

Patton, W. W., Jr., 1971, Mesozoic tectonics and correlations in 

Yukon-Koyukuk province, west-central Alaska [abs.]: Am. 

Assoc. Petroleum Geologists Bull., v. 54, p. 2500. 

Patton, W. W., Jr., and Csejtey, Bela, Jr., 1971, Preliminary geologic investigations of western St. Lawrence Island, Alaska: 

U.S. Geol. Survey Prof. Paper 684-C, p. C1-C15. 

Sauer, J. F. T., Tully, J. F., and La Fond, E. C., 1954, Oceanographic cruise to the Bering and Chukchi Seas, summer 1949; 

Pt. IV, Physical oceanographic studies: U.S. Navy Electronics Lab. Rept. 416, v. 1, 31 p. 

Scholl, D. W., and Marlow, M.S., 1970, Bering Sea seismic profiles, 

1969: U.S. Geol. Survey open-file report. 

Sharma, G. D., Wright, F. F., Bums, J. J., and Burbank, D. C., 

1974, Sea surface circulation, sediment transport, and marine 

mammal distribution, Alaska continental shelf; ERTS Final 

Report: Natl. Tech. Inf. Service Rept. E74-10711, 77 p. 

Shepard, F. P., 1963, Submarine geology, 2d ed.: New York, 

Harper & Row, 557 p. 

Silberman, M. L., 1969, Preliminary report on electron microscopic examination of surface textures of quartz sand grains 

from the Bering shelf in Geological Survey research 1969: 

U.S. Geol. Survey Prof. Paper 650-C, p. C33-C37. 

Smith, J. D., and Hopkins, T. S., 1972, Sediment transport on the 

continental shelf off of Washington and Oregon in the light of 

recent current measurements, in Swift, D. J.P., Duane, D. B., 

and Pilkey, 0. H., eds., Shelf sediment transport; process and 

pattern: Stroudsburg, Penn., Dowden, Hutchinson, and Ross, 

p. 143-180. 

Snedecor, G. W., 1956, Statistical methods applied to experiments 

in agriculture and biology, 5th ed.: Ames, Iowa, Iowa State 

College Press, 534 p. 

Sternberg, R. W., 1971, Measurements of incipient motion of sediment particles in the marine environment: Marine Geology, 

v. 10, p. 113-119. 

Sundborg, A., 1956, The River Klaralven-a study of fluvial processes: Geografiska Annaler, v. 38, p. 127-316. 

Sverdrup, H. U., Johnson, M. W., and Fleming, R. H., 1942, The 

oceans, their physics, chemistry, and general biology: Englewood Cliffs, N.J., Prentice-Hall, 1087 p. 

Swift, D. J. P., Stanley, D. J., and Curray, J. R., 1971, Relict 

sediments on continental shelves-a reconsideration: Jour. 

Geology, v. 79, p. 322-346. 

Taber, Stephen, 1943, Perennially frozen ground in Alaska; its 

origin and history: Geol. Soc. America Bull., v. 54, p. 1433-

1548. 

Tagg, A. R., and Greene, H. G., 1973, High-resolution seismic 

survey of an offshore area near Nome, Alaska: U.S. Geol. 

Survey Prof. Paper 759-A, p. A1-A23. 

Tilman, S.M., Belyi, V. F., Nikolaevskii, A. A., and Shilo, N. A., 

1969, Tektonika Severo-vostoka SSSR (Tectonics of northeastern USSR): Akad. Nauk SSR, Sibirsk. Odel., SeveroVostoch. Nauchno-Issled. Inst., Trudy 33, 78 p. [Translation 

available from Nat. Translation Center, Chicago]. 

U.S. Beach Erosion Board, 1961, Shore protection, planning and 

design: U.S. Army Corps Engineers Beach Erosion Board 

Tech. Rept. 4, 242 p. 

U.S. Coast and Geodetic Survey, 1964, United States Coast Pilot, 

v. 9, Pacific and Arctic coasts, Alaska-Cape Spencer to 

Beaufort Sea, 7th ed.: Washington, D.C., U.S. Govt. Printing 

Office, 330 p. 

Venkatarathnam, Kolla, 1971, Heavy minerals on the continental 

shelf of the northern Bering Sea: U.S. Geol. Survey openfile report, 92 p. 

Wiegel, R. L., 1964, Oceanographic engineering: Englewood 

Cliffs, N.J., Prentice-Hall, 532 p.