Grain .. Size, ~~vy .. MEtJ~raf, an(J 

G ,c:'hemiu · tfl<ll~ .l Sed~ .. Hots: 

from 'the Ch hi Sea"~ ·fasKa 

U.S. GEOLOGICAL ] SURVEY BULLETIN 1896 ! 

) 
AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY 

Instructions on ordering publications of the U.S. Geological Survey, along with prices of the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Survey publications released prior to the current year are listed in the most recent annual "Price and Availability List" Publications 

that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and 

Availability List" are no longer available. 

Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated monthly, which is for sale in microfiche from the U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box 

25425, Denver, CO 80225. Reports released through the NTIS may be obtained by writing to the National Technical Information 

Service, U.S. Department of Commerce, Springfield, VA 22161; please include NTIS report number with inquiry. 

Order U.S. Geological Survey publications by mail or over the counter from the offices given below. 

BY MAIL 

Books 

Professional Papers, Bulletins, Water-Supply Papers, Techniques 

of Water-Resources Investigations, Circulars, publications of general interest (such as leaflets, pamphlets, booklets), single copies of Earthquakes 

& Volcanoes, Preliminary Determination of Epicenters, and some miscellaneous reports, including some of the foregoing series that have gone 

out of print at the Superintendent of Documents, are obtainable by mail 

from 

U.S. Geological Survey, Books and Open-File Reports 

Federal Center, Box 25425 

Denver, CO 80225 

Subscriptions to periodicals (Earthquakes & Volcanoes and 

Preliminary Determination of Epicenters) can be obtained ONLY from 

the 

Superintendent of Documents 

Government Printing OMce 

Washington, D.C. 20402 

(Check or money order must be payable to Superintendent of Documents.) 

Maps 

For maps, address mail orders to 

U.S. Geological Survey, Map Distribution 

Federal Center, Box 25286 

Denver, CO 80225 

Residents of Alaska may order maps from 

Alaska Dhtrlbutlon Section, U.S. Geological Survey, 

New Federal Building - Box 12 

101 Twelfth Ave., Fairbanks, AK 99701 

OVER THE COUNTER 

Books 

Books of the U.S. Geological Survey are available over the 

counter at the following Geological Survey Public Inquiries Offices, all 

of which are authorized agents of the Superintendent of Documents: 

• WASHINGTON, D.C.--Main Interior Bldg., 2600 corridor, 

18th and C Sts., NW. 

• DENVER, Colorado--Federal Bldg., Rm. 169, 1961 Stout St. 

• LOS ANGELES; California--Federal Bldg., Rm. 7638, 300 N. 

Los Angeles St. 

• MENLO PARK, California--Bldg. 3 (Stop 533), Rm. 3128, 

345 Middlefield Rd. 

• RESTON, Vtrglnla--503 National Center, Rm. 1C402, 12201 

Sunrise Valley Dr. 

• SALT LAKE CITY, Utah--Federal Bldg., Rm. 8105,125 

South State St. 

• SAN FRANCISCO, California--Customhouse, Rm. 504, 555 

Battery St. 

• SPOKANE, Washington--U.S. Courthouse, Rm. 678, West 

920 Riverside Ave .. 

• ANCHORAGE, Alaska--Rm. 101,4230 University Dr. 

• ANCHORAGE, Alaska--Federal Bldg, Rm. E-146. 701 C St. 

Maps 

Maps may be purchased over the counter at the U.S. Geological Survey offices where books are sold (all addresses in above list) and 

at the following Geological Survey offices: 

• ROLLA, M.lssourl--1400 Independence Rd. 

• DENVER, Colorado--Map Distribution, Bldg. 810. Federal 

Center 

• FAIRBANKS, Alaska--New Federal Bldg., 101 Twelfth Ave. 
Grain-Size, Heavy-Mineral, and 

Geochemical Analyses of Sediments 

from the Chuckchi Sea, Alaska 

By GRETCHEN LUEPKE and EDWARD C. ESCOWITZ 

U.S. GEOLOGICAL SURVEY BULLETIN 1896 
DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, jR., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names 

in this publication is for descriptive purposes only 

and does not imply endorsement by the U.S. Government 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1989 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center, Box 25425 

Denver, CO 80225 

Library of Congress Cataloging-in-Publication Data 

Luepke, Gretchen 

Grain-size, heavy-mineral, and geochemical analyses of sediments from the 

Chukchi Sea, Alaska I by Gretchen Luepke and Edward C. Escowitz. 

p. em. - (United States Geological Survey bulletin ; 1896) 

Includes bibliographical references. 

Supt. of Docs. no. : I 19.13:1896 

1. Heavy minerals-Alaska. 2. Heavy minerals--Chukchi Sea. 

3. Sediments (Geology)-Aiaska. 4. Sediments {Geology)-Chukchi Sea. 

I. Escowitz, Edward C. II. Title. Ill. Series. 

QE75.B9 no. 1896 557.3 s--dc20 89-600223 

[TN24.A4] [553.4'09798] CIP 
CONTENTS 

Abstract 1 

Introduction 1 

Acknowledgments 1 

Methods 1 

Results 4 

Grain-size analysis 4 

Heavy-mineral content 4 

Geochemical analysis 6 

Conclusions 6 

References cited 6 

FIGURES 

1. Index map showing locations of samples in the Chukchi Sea, Alaska 2 

2. Flow chart for processing of Chukchi Sea samples 3 

3. Histograms of grain sizes in samples from the Chukchi Sea 4 

TABLES 

1. Locations, water depths, size fractions, and groupings of samples taken from 

the Chukchi Sea 3 

2. Heavy-mineral analysis of dredge and box-core samples from the Chukchi 

Sea 5 

3. Emission spectrographic analyses of samples from the Chukchi Sea 10 

4. Statistics of major and minor elements detected in designated heavy-mineral 

fractions of samples from the Chukchi Sea 12 

Contents Ill 

Grain-Size, Heavy-Mineral, and Geochemical Analyses 

of Sediments from the Chukchi Sea, Alaska 

By Gretchen Luepke and Edward C. Escowitz 

Abstract 

The heavy-mineral assemblage in sediments of dredge and 

box-core samples from the Chukchi Sea, Alaska, is dominated 

by pyroboles. Other minerals occurring in measurable amounts 

include ilmenite and chromite, garnet, magnetite, and epidote. 

Minerals of economic value-ilmenite, leucoxene, chromite, 

rutile and zircon-constitute an average of about 23 percent of 

the heavy minerals in the analyzed sediments and an average of 

about 0.05 percent of the bulk samples. The overall scarcity of 

economic mineral species, extremely low total heavy minerals in 

the sediments, and generally thin sand cover of the sea floor 

show that the economic placer potential for the coastal area of 

the Chukchi Sea northeast of Cape Lisburne is negligible. 

INTRODUCTION 

As part of the U.S. Geological Survey (USGS) 

effort to assess the potential for placer deposits on the 

continental shelves in the Exclusive Economic Zone, the 

present study examines the sediments of the coastal 

northeastern Chukchi Sea off northern Alaska (fig. 1). 

Because no metallic-mineral lodes or valuable placer 

deposits exist anywhere on the Alaskan coast adjacent to 

the Chukchi Sea (Cobb, 1973), it has been speculated 

that the Chukchi Sea is an unlikely place for placers 

(Clifton and Luepke, 1987). However, no systematic 

analysis of the economic placer potential of the Chukchi 

Sea has ever been attempted, and no descriptions of 

heavy minerals from the Chukchi Sea have been previously published. 

The Chukchi Sea is a broad shelf that is icebound 

for approximately 9 months of the year. The sea floor in 

the northern part has a thin veneer (2 to 5 m) of 

unconsolidated sediments, mostly sand and gravel, that 

covers well-indurated bedrock; in the southern part, the 

unconsolidated sediments are as thick as 11 m (Grantz 

and others, 1982). In the study area, the sands and 

gravels are relict and contain essentially no silt or clay 

(McManus and others, 1969). Substantial gravel accuManuscript approved for publication, May 26, 1989. 

mulations occur near Cape Lisburne, and smaller accumulations occur near Icy Cape. Sand is concentrated 

beneath the main course of the Alaska coastal current 

from Point Hope to Point Franklin (Grantz and others, 

1982). This current could act as a concentrating mechanism for placers. 

The Alaskan coast bordering the Chukchi Sea is 

part of the Arctic Coastal Plain geomorphic province, 

primarily a low-lying tundra dotted with lakes. The 

foothills of the Brooks Range border the coast northeast 

of Cape Lisburne for about 137 km. The Utukok River, 

with its mouth at Icy Cape, drains the westernmost 

Brooks Range; all other rivers in the coastal area represent local drainages. The geology of the area is almost 

uniform. The Pliocene and Pleistocene Gubik Formation, consisting of mostly marine cross-bedded gravel, 

sand, silt, and clay, underlies the coastal plain in the study 

area from Skull Cliff to beyond Point Barrow. Permian 

and Triassic clastic and carbonate rocks, which are 

exposed in cliffs at Cape Lisburne (Beikman, 1980), ar~ 

the primary source for the relict gravels immedately 

offshore (McManus and others, 1969). Cretaceous sedimentary rocks are exposed along the remainder of the 

coast and at Skull Cliff under the Gubik Formation 

(Beikman, 1980). 

Acknowledgments 

We thank Mark Brown for the sample processing 

to concentrate the heavy minerals and Robert Oscarson 

for SEM and EDAX analysis. 

METHODS 

Samples used in this study were taken during a 

cruise aboard the National Oceanographic and Atmospheric Administration ship Discoverer in August 1985. 

Four dredge and six box-core samples were collected 

with a 40-cm-diameter pipe dredge and a Reineck-type 

box corer, respectively. The pipe dredge was completely 

filled during sampling, so no winnowing of material was 

Methods 1 
. evident. The box corer samples a 31 X22X60-cm3 

segment of sea floor (Barnes and others, 1986). The 

samples were taken to study bedforms and biology in the 

area beneath the Alaska coastal current. This focus also 

allowed the samples to be taken commonly in lag gravels, 

where any heavy minerals were likely to be concentrated. 

Sample locations are shown on figure 1. The locations, water depths, size fractions, and groupings of 

samples are given in table 1. Two composite samples 

were made by combining two and three of the box-core 

samples, respectively, on the basis of their nearly identical locations. Combination of box-core samples for 

heavy-mineral analysis ensures a sample large enough to 

reduce the possiblility of a particle-sparsity bias that can 

25-35 OS 

result when a limited number of grains significantly 

influences the concentration of an economically important mineral species (see Clifton and others, 1969). 

The resulting samples were analyzed for their grain 

size, heavy-mineral, and geochemical content of the 

heavy-mineral fraction. A flow chart for sample processing is given in figure 2. The gravel-size ( > 2.0 mm) 

material in the samples was removed on shipboard and 

studied separately (Barnes and others, 1986). R.L. Phillips is preparing visual descriptions of the box-core and 

dredge samples. 

The sand samples (grain size 0.062 to 2.0 mm) 

were sent to Reston, Virginia, where a repository subsample (average weight 575 g) of each sample was 

46-61 BS, 

46-62,63 as. " 

21-32 os • 

., 

Point 

Barrow 

e e 35-47 OS 

.;1 0~\. ~ ........ 

:\(j 

\.'I> 

'l>r:, 

vo 

• 68-88, 

89,90 BS 

50 

ALASKA 

100 KILOMETERS ···" • •• ~0 

Figure 1. Index map of the Chukchi Sea, Alaska, showing sample locations for this report. Sample numbers include type of 

sample (BS, box-core; OS, dredge). Arrows indicate primary direction of the Alaska coastal current. Drawn from National 

Oceanographic and Atmospheric Administration (NOAA) National Ocean Survey Chart 16005 (Cape Prince of Wales to Point 

Barrow, 1980, scale 1 :700,000). 

2 Analyses of Sediments from the Chukchi Sea, Alaska 
Table 1. Locations, water depths, size fractions, and groupings of samples taken 

from the Chukchi Sea, Alaska 

[Braces indicate samples combined for heavy-mineral analysis. DS, dredge sample; BS, box-core 

sample; *,presence of silt and clay detected with rapid sediment analyzer (see fig. 3); -,value 

not calculated because it would be statistically meaningless] 

Weight percent of sample 

Sample latitude 1 longitude 1 Water Gravel Sand Silt and clay 2 

number N. w. depth (>2.0 mm) (2.0- (<0.062 mm) 

(m) 0.062 mm) 

21-32 DS 71.015 159.267 60 48.9 51.1 0 

23-34 DS 70.728 160.202 30 18.7 81.3 * 

25-35 DS 70.608 162.390 42 0 100 0 

35-47 DS 70.593 161.902 41 6.9 93.1 0 

46--61 BS 71.103 158.483 35 <0.1 99.9 * 

46--62 BS 71.108 158.482 37 } 0 100 0 46--63 BS 71.118 158.482 38 

68-88 BS 69.902 164.792 38 } 68-89 BS 69.900 164.778 38 <0.1 99.9 0 

68-90 BS 69.900 164.773 38 

Minimum value - - - - - - - - - - - - - - - - - - - - - - 0 51.1 0 

Mean value _________________ ... ______ 89.3 

Maximum value - - - - - - - - - - - - - - - - - - - - - - 48.9 100.0 * 

Standard deviation - - - - - - - - - - - - - - - - - - - - - 18.2 

1

Latitude and longitude expressed in degrees to the nearest thousandth. 2All samples contained <0.1 percent silt. 

separated. From the remaining volume of each sandsized sample, ranging in weight from about 8,000 g to 

nearly 22,000 g, heavy minerals were removed, following 

Sand 

Shipboard sample 

(table 1) 

S. I . 1ze separations 

Subsamples 

Repository 

RSA 

(fig. 3) 

I 

1/4 

Heavy minerals 

SG >2.96 

Sample I splits 

I 

Gravel 

Light minerals 

SG <2.96 

3/4 

HMAG 0-0.6 >0.6 HMAG 0-0.2 0.2- 0.4- 0.6- >1.8 

0.4 0.6 1.8 

Geochemical analyses 

( tables 3, 4 ) 

Optical analyses 

(table 2) 

Figure 2. Flow chart for processing of samples from Chukchi 

Sea, Alaska. RSA, rapid sediment analyser; SG, specific 

gravity; HMAG, hand-magnet separation; electromagnetic 

separation numbers in amps. 

the wet-milling process described in Luepke and Grosz 

(1986). After the wet-milling process, the heavy-mineral 

concentrates were further purified using a Magstream 

Model 1000E separator. This device, which uses ferrofluids as the separating medium, replaces heavy liquids in 

the concentration process (Urbanski and others, 1987). 

The repository samples and heavy-mineral concentrates were then returned to the USGS Marine Geology 

sedimentation laboratory in Menlo Park, California. 

Grain-size analyses were made from a split of about 0.7 

grams from each of the repository samples, using a rapid 

sediment analyzer (RSA) .(Thiede and others, 1976). 

Settling velocities for the sand-sized particles are calculated from the equations of Gibbs and others (1971). 

A quarter split of each heavy-mineral fraction was 

taken: half for geochemical analyses and half for repository. The analytical split was separated by magnetic 

techniques (Luepke and Grosz, 1986) into three paramagnetic subfractions: one strongly magnetic (separable 

by hand magnet or = 0 amp), and two separable by an 

electromagnet set at 0.6 amp. A D-C arc 3-mm grating 

spectrograph was used to test for 64 minor elements by 

inductively coupled argon plasma- atomic emission spectrometry (ICAP-AES). This rapidanalysis method yields 

semiquantitative data (Lichte and others, 1987). 

The remaining three-quarters split of each heavymineral fraction was separated into six paramagnetic 

subfractions: strongly magnetic, 0.0 to 0.2, 0.2 to 0.4, 0.4 

Methods 3 
to 0.6, 0.6 to 1.8, and > 1.8 amp. Each magnetic fraction 

was weighed and examined using binocular and petrographic microscopes. Long-wave and unfiltered shortwave ultraviolet illuminations were used with other optical properties to detect zircon and monazite, respectively. 

X-ray diffraction was used to check the bulk mineralogy 

of a representative aliquot of each subfraction. Selected 

mineral grains were examined using a scanning electron 

microscope (SEM), and an energy dispersive X-ray analyzer (EDAX), to aid in confirming mineral identification. 

RESULTS 

Grain-Size Analysis 

Gravel percentages range from 0 to nearly 50 

percent (table 1 ). The grain-size distribution histograms 

for the sand-sized fractions are shown in figure 3. Except 

for samples 21-32 DS, 46-61 BS, and 46-62, 63 BS, 

which have bimodal grain-size distributions, the sands of 

the remaining samples are well sorted. The mode peak of 

the well-sorted samples and the primary mode peak of 

the bimodal samples fall in the medium-sand range 

(0.125 to 0.250 mm, around 2.0 or 2.5c{> ). Only two 

histograms, 23-34 DS and 46-61 BS, show any material 

in the silt-size range ( < 0.062 mm, or < 4cf> ). 

60 35-47 DS 

23-34 DS 25-35 DS 50 

40 

Iz 21-32 OS w 

(.) 30 

!~ a: 

w 

J~ a.. 20 

IJ~ :I: J Cl 

- 10 w 

3: 

~ <,. 

0 I 2 3 4 0 1 2 3 4 0 1 2 3 • 0 1 2 3 4 

_j GRAIN SIZE (CIJ) ~ 

a: 

w 

I- 46-61 BS 46-62,63 BS < :::ii 50 " J 68-88,89,90 BS 

u.. 'I 

0 I 

I- 40 

I z 

::;) 

0 30 

:::ii 

< ,--1 

20 

10 

0 1 

.- 2 

"-, 

3 4 

,...., -1 

fl. 0 

J 

1 2 

'L. 

3 4 0 

.I 

1 2 

~ 3 4 

GRAIN SIZE (cp) 

Figure 3. Histograms of grain sizes in samples from Chukchi 

Sea, Alaska. 

4 Analyses of Sediments from the Chukchi Sea, Alaska 

Heavy-Mineral Content 

The weight percentages of heavy minerals identified in the sediments (table 2) were calculated according 

to the method described in Luepke and Grosz (1986). 

Minerals identified include magnetite, ilmenite + 

chromite, leucoxene, garnet, epidote group, pyroboles 

(pyroxenes and amphiboles), sphene, apatite, zircon, and 

rutile. Minerals occurring only in trace amounts include 

mica, kyanite, staurolite, chloritoid, tourmaline, limonite, 

anatase, pyrite, hematite, corundum(?), andalusite(?), 

and beryl(?). A bright aqua-blue mineral, tentatively 

identified as the beryl variety aquamarine, was noted in 

samples 21-32 DS and 46-61 BS. An unknown, pale-pink 

mineral (rhodonite?) was also seen; according to EDAX 

analysis, it contains manganese. 

Minerals designated as "Others" are altered grains 

that cannot be precisely identified. The dusty appearance 

of these grains, especially when the overall grain size was 

fine to very fine ( < 0.125 mm), is attributed to extreme 

weathering. From EDAX analysis, titanium appears to 

be a minor constituent of many of these grains. 

The ratio of pyroxenes to amphiboles in all ~amples 

is at least 2:1 and commonly more; the ratio of clinopyroxene to orthopyroxene is about 5:1. These ratios are 

based on point counts of grain mounts. Pyroxenes identified in grain mounts include augite, diopside, and 

hypersthene; amphiboles include green and blue-green 

hornblende, with rare brown and basaltic hornblende and 

glaucophane. The epidote group includes both epidote 

and clinozoisite. 

Magnetite percentages show the greatest variability. Magnetite inclusions are common in both garnet and 

hypersthene grains. Limonite occurs occasionally as a 

coating on other grains. Zircon constitutes from about 1 

to 3 percent of the heavy-mineral fraction; grains are 

mostly colorless, but some are pink. Rutile and sphene 

occur from trace amounts to about 1 percent of the 

heavy-mineral fraction. 

Differentiating between ilmenite and chromite 

grains is commonly difficult. For this reason, ilmenite and 

chromite percentages are combined in table 2. However, 

geochemical data in tables 3 and 4, combined with X-ray 

and EDAX analyses, show that ilmenite is probably the 

more common of the two. 

Apatite in the Chukchi Sea sediments has two 

distinct forms, clear and black; the black variety is more 

common. Black apatite was found primarily in the 0.6- to 

1.8-amp fraction. Both varieties were confirmed by 

EDAX. The presence of the rare-earth elements cerium 

and lanthanum was noted in one black apatite grain; this 

grain was anomalous in that it also contained high levels 

of strontium and aluminum and low levels of calcium and 

iron. Although no other black apatite grains examined 

displayed these elements, this analysis may be indicative 
:a 

CD 

0 

c 

i 

Ul 

Table 2. Heavy-mineral analyses of dredge (DS) and box-core (BS) samples from the Chukchi Sea, Alaska 

[S.G., specific gravity; EHM, economic heavy minerals; C, heavy-mineral concentrate; T, total sample; Tr, trace ( <0.1 in EHM!f column, < 0.5 in other columns);-, value not calculated 

because it would be statisically meaningless] 

Weight percent of minerals having S.G. >2.96 

Weight 

Sample percent of Magnetite !Ilmenite leucoxene Mica Garnet Epidote Pyroboles 2 Sphene Apatite Zircon Rutile Trace Others 4 

number sample having 

S.G. >2.96 

21-32 OS 0.08 11.4 

23-34 OS .23 3.2 

25-35 OS .20 6.9 

35-47 OS .24 11.5 

46-61 BS .47 3.8 

46-62,63 BS .36 5.9 

68-88,89,90 BS .39 3.6 

Minimum value .08 3.2 

Mean value .28 6.6 

Maximum value .47 11.5 

Standard deviation .13 3.6 

1

Includes epidote and clinozoisite. 2Pyroxenes plus amphiboles. 

+ chromite 

15.8 3.1 Tr 12.0 

17.2 3.3 Tr 13.1 

15.0 4.0 Tr 8.4 

17.6 3.0 Tr 12.6 

13.0 .9 Tr 12.9 

14.1 1.3 Tr 14.5 

21.0 1.0 0.5 6.2 

13.0 .9 Tr 6.2 

16.2 2.4 - 11.4 

21.0 4.0 .5 14.5 

2.6 1.3 - 3.0 

group 1 minerals 3 

7.4 44.0 Tr 0.6 2.5 6Tr 0.5 

10.9 38.6 0.8 1.0 2.8 0.9 Tr 

8.3 49.1 Tr 1.4 1.3 Tr Tr 

8.6 34.6 .5 1.7 3.0 6.8 Tr 

8.0 54.4 Tr 1.7 1.4 .6 Tr 

9.9 45.7 .5 1.3 1.4 1.1 Tr 

8.7 45.7 Tr .9 3.2 1.1 Tr 

7.4 34.6 Tr .6 1.3 Tr Tr 

8.8 44.6 .4 1.2 2.2 .7 - 10.9 54.4 .8 1.7 3.2 1.1 .5 

1.2 6.5 .2 .4 .8 .3 -

3Most samples show traces of kyanite, staurolite, chloritoid, tourmaline, and limonite; some show pyrite, hematite, corundum(?), beryl(?), and andalusite(?). 4 Altered minerals that cannot be positively identified. 

'llmenite + chromite, leucoxene, rutile, and zircon. 6 Anatase seen in this sample. 

1.7 

8.0 

4.6 

6.0 

2.6 

3.9 

7.7 

1.7 

4.9 

8.0 

2.1 

EHM/C5, EHM/T 5

, 

sum of weight 

percentages percent 

21.7 0.01 

24.2 .04 

20.7 .03 

24.4 .04 

15.9 .06 

17.9 .05 

26.3 .08 

15.9 .01 

21.6 .04 

26.3 .08 

3.7 .02 
of the possible variability in composition of the black 

apatite. 

Geochemical Analysis 

Results of geochemical analyses for each magnetic 

subfraction of each sample are given in table 3; the 

cumulative statistics for all samples in each magnetic 

range are given in table 4. The statistics within ranges in 

table 4 are divided into two categories: (1) major elements, with values in percent, and (2) minor elements, 

with values in parts per million. The detection ranges for 

each of the 64 elements sought are given in table 3. 

The geochemical data generally support the optical 

determination of mineral assemblages. For example, 

sample 68-88,89,90 BS, which ranks first in ilmenite+ 

chromite as determined optically, also ranks first in 

titanium and chromium concentrations determined by 

emission spectrography. In the other six samples of this 

study, the rank order of the spectrographically determined titanium and chromium concentrations also parallels that of the optically determined ilmenite + 

chromite. 

Some variance is expected from strict correlation 

because titanium is present in other minerals such as 

leucoxene, rutile, and sphene. EDAX data indicate that 

many of the pyrobole minerals also contain titanium. 

Sample 46--62,63 BS, which ranks first in concentrations 

of rutile and sphene, ranks second in overall titanium 

concentration. This sample has the most mature heavymineral assemblage (high percentage of stable unaltered 

heavy minerals) and has a primary mode in the fine-sand 

(approx. 2.5q,) size range in the grain-size distribution 

(fig. 3). 

Although monazite was not detected with the unfiltered short-wave ultraviolet light, the presence of detectable amounts of cerium, lanthanum, yttrium, yttterbium, 

and thorium in the > 0.6-amp geochemical fraction of all 

samples may imply its presence. The total would, however, be only trace amounts in the total heavy-mineral 

fraction. The detectable amount of silver in each sample 

is puzzling and cannot be immedately explained. 

Attempts to find patterns or trends in the heavymineral and geochemical distributions were generally 

unsuccessful. The samples may be too few and too widely 

spaced to detect any trends. However, the lack of any 

noticeable difference in such widely scattered samples 

would seem to indicate a true lack of variability. The 

large variety of minerals identified in the northeastern 

Chukchi Sea indicates an overall immaturity of sediments. This mineral variety and immaturity has also been 

noted in Beaufort Sea sediments east of Point Barrow 

(Luepke, 1975). Coastal erosion of the Gubik Formation 

is probably the major source for sediments in both the 

Beaufort and Chukchi Seas. The lack of nearby sources 

6 Analyses of Sediments from the Chukchi Sea, Alaska 

of economic heavy minerals is the primary reason for lack 

of heavy-mineral placers in the Chukchi Sea north of 

Cape Lisburne. 

CONCLUSIONS 

After the removal of gravel, the mean grain size of 

samples examined for this study is within the mediumsand range (0.125 to 0.25 mm). The sand varies from 

poorly to well sorted. The Alaska coastal current effectively removes most silt- and clay-size material. 

The economically important heavy minerals identified in the Chukchi Sea samples are ilmenite, chromite, 

leucoxene, zircon, and rutile. On the basis of geochemical 

analyses, monazite may be present but only in ~race 

amounts. The weight percentages of the economically 

important minerals (EHM!f column, table 2) in the 

samples of sediments of the Chukchi Sea constitute only 

a trace amount of whole samples, ranging from 0.01 to 

0.08 percent, or about 20 to 26 percent of the heavymineral fraction (EHM/C column, table 2). Equally 

important, no bulk sample contained more than 0.5 

percent heavy minerals. Among the more important 

economic elements, no gold, tungsten, tantalum, uranium, or platinum-group elements were detected in any 

sample. On the basis of the samples analyzed, the potential for significant economic heavy-mineral concentrations in the Chukchi Sea north of Cape Lisburne appears 

to be negligible. 

REFERENCES CITED 

Barnes, P.W., Miley, J.M., and Phillips, R.L., 1986, Marine 

geological studies in the Beaufort and Chukchi Seas-introduction, methods, and equipment, in Miley, J.M. and 

Barnes, P.W., eds., 1985 field studies, Beaufort and 

Chukchi Seas, conducted from the NOAA ship Discoverer. U.S. Geological Survey Open-File Report 86-202, 

p. 2-28. 

Beikman, H.M. (compiler), 1980, Geologic map of Alaska: U.S. 

Geological Survey, 2 sheets, scale 1:2,500,000. 

Clifton, H.E., and Luepke, Gretchen, 1987, Heavy-mineral 

placer deposits of the continental margin of Alaska and 

Pacific Coast states, in Scholl, D.W., Grantz, Art, and 

Vedder, J.G., eds., Geology and resource potential of the 

continental margin of western North America and adjacent ocean basins-Beaufort Sea to Baja California: 

Houston, Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 6, chap. 30, p. 

691-738. 

Clifton, H.E., Hunter, R.E., Swanson, FJ., and Phillips, R.L., 

1969, Sample size and meaningful gold analysis: U.S. 

Geological Survey Professional Paper 625-C, 17 p. 

Cobb, E.H., 1973, Placer deposits of Alaska: U.S. Geological 

Survey Bulletin 1374, 213 p. 

Gibbs, R.J., Mathews, M.D., and Link, DA., 1971, The relationship between sphere size and settling velocity: Journal of Sedimentary Petrology, v. 41, no. 1, p. 7-18. 
Grantz, Arthur, Dinter, DA., Hill, E.R., Hunter, R.E., May, 

S.D., McMullen, R.H., and Phillips, R.L., 1982, Geologic 

framework, hydrocarbon potential and environmental 

conditions for exploration and development of proposed 

oil and gas lease sale 85 in the central and northern 

Chukchi Sea-A summazy report: U.S. Geological Survey Open-File Report 82-1053, 89 p. 

Lichte, F.E., Meier, A.L., and Crock, J.G., 1987, Determination 

of the rare-earth elements in geological materials by 

inductively coupled argon plasma-atomic emission spectrometzy: Analytical Chemistry, v. 59, no. 8, p. 

1150-1157. 

Luepke, Gretchen, 1975, Heavy mineral trends in the Beaufort 

Sea: U.S. Geological Sutvey Open-File Report 75-667, 

32 p. 

Luepke, Gretchen, and Grosz, A.E., 1986, Distribution of 

economic heavy minerals of Saco Bay, Maine: U.S. 

Geological Sutvey Bulletin 1681, 12 p. 

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

Geological Society of America Bulletin, v. 80, no. 10, p. 

1961-1984. . 

Thiede, J~m, Chriss, Terry, Clauson, Milo, and Swift, S.A., 

1976, Settling tubes for size analysis of fine sand and 

coarse fractions of oceanic sediments: Cotvallis, Oregon 

State University, School of Oceanography Reference 

76-8, 87 p. 

Thomas, C.P., 1979, A minicomputer-based emission spectrographic analysis system dependent on scanning microphotometry: Applied Spectroscopy, v. 33, no. 6, p. 

604-612. 

Urbanski, W.S., Devernoe, A.L., and Walker, M.S., 1987, A 

new non-toxic procedure for the concentration of conodonts: Society of Economic Paleontologists and Mineralogists, Midyear Meeting, Austin, Texas, 1987, 

Abstracts with Program, v. 4, p. 85. 

References Cited 7 

TABLES 3 and 4 
Table 3. Emission spectrographic analyses of samples from the Chukchi Sea, Alaska 

[Analyst, Carol J. Skeen; plate recorder, William D. Crandell. Samples separated by hand magnet (HMAG) and electromagnet ( < 0.6 amp and > 0.6 amp) 

H, exceeds upper limit of detection; E, occurrence of unresolved interference] 

Sample 21-32 OS Sample 25-35 OS Sample 2 3-34 OS Sample 3.5-47 OS 

Element 

HMAG <0.6 amp >0.6 amp HMAG <0.6 amp >0.6 amp HMAG <0.6 amp >0.6 amp HMAG <0.6 amp >0.6 amp 

Ag (ppm) 2.0 0.9 2.8 1.5 9.6xto-t 1.4 2.1 8.8x10-l 5.9 1.9 7.7xlo-t 5.0 

AI (pet) 5.6 5.7 1.1 2.8 7.8 1.2 3.3 7.6 3.0 5.2 5.5 2.1 

As (ppm) L L L L L L L L L L L L 

Au (ppm) L L L L L L L L L L L L 

B (ppm) 5.lxl01 1.8x102 9.4xl01 L 4.2xlo2 1.4xl02 2.0xlo2 4.4xlo2 7.4xl01 7.2xl01 3.3xlo2 8.9xl01 

Ba (ppm) 2.5xlo2 2.5xl02 6.9xl03 1.3xlo2 2.8xlo2 1.3xl0" 8.6xl01 1.7xl02 1.4xl0" 9.7xl01 2.5xlo2 2.1xl04 

Be (ppm) L L 5.3 L L L L L 1.8 L L L 

Bi (ppm) L L L L L L L L L L L L 

Ca (pet) 4.3 6.9 3.8 2.4 l.Oxl01 4.2 2.3 8.3 9.8 3.2 7.9 6.2 

Cd (ppm) L L L L L L L L L L L L 

Ce (ppm) L 5.6xlo2 4.8xlo2 L 5.0xlo2 9.9xlo2 L 4.lxl02 l.lxlol L 5.8xl02 7.9xl02 

Co (ppm) 4.6xl01 3.3xl01 6.8 4.2xl01 3.7xl01 6.6 6.0xl01 4.8xl01 LOxl01 5.9xl01 3.5xl01 7.1 

Cr (ppm) 1.9xl03 1.7xl04 6.3xl02 1.7xlol 1.8xl03 3.2xl02 2.9xlol 2.9xlol 4.4xl02 3.lxlol 2.5xlol 2.lx102 

Cu (ppm) 3.3xl01 l.lxl01 1.4xl01 7.0xl01 6.9xl01 2.3x101 3.5xto1 3.2xl01 L 7.Ixi01 7.8xl01 5.4x101 

Dy (ppm) L L E L L E L L E L L E 

Er(ppm) L L E L L E L L E L L E Eu (ppm) L 4.7 9.9 L L 9.0 L L 2.0xl01 L L 1.5xl01 

Fe (pet) H 1.4xl01 1.2 H 1.7x101 1.3 2.0xl01 1.6xl01 1.1 H 1.5xl01 1.0 

Ga (ppm) E l.5xl01 4.5 E 1.7xl01 6.8 2.5xl01 3.2xl01 6.5 E l.8xl01 4.3 

Gd (ppm) L L L L L L L L L L L L 

Ge (ppm) L L L L L L L L L L L L Hf (ppm) L L l.Oxlol L L 3.0xl02 L L 1.3xlol L L 1.7xl03 

Ho (ppm) L L L L L l.3xl01 L L L L L 3.3xl01 

In (ppm) L L L L L L L L L L L L 

Ir (ppm) L L L L L L L L L L L L 

K (pet) 4.7xlo-1 2. 7xlo-t 2.6xto-1 4.lxlo-1 3.lxlo-1 2.2x1o-1 0.4 0.3 3.5xto-1 3.7xlo-1 3.lxlo-1 2.0x1o-1 

La (ppm) 3.7xl01 2.2xlo2 1.7xlo2 L 2.0x102 1.7xlo2 3.7xl01 1.8xlo2 4.7xl02 3.2xl01 2.2x102 3.4xl02 

Li (ppm) E L L E E L E E L E L L 

Lu (ppm) L L L L L L L L 2.6xl01 L L 2.Ixl01 

Mg (pet) 4.6 9.1 6.8xlo-1 3.5 8.4 6.9xto-1 3.8 7.5 5.7xto-t 3.8 6.0 5.5xto-1 

Mn (ppm) 1.3xl04 8.lxlol 2.0xl02 9.2xlol 6.2xl03 3.6xl02 1.2xl04 7.0xl03 3.9xlo2 l.lxl04 5.9xl0' 1.8xlo2 

Mo (ppm) E 2.6 L E 3.2 L 5.8 2.0 L E 4.3 L 

Na (pet) 3.lxto-1 2.7xto-1 2.4xlo-1 2.6xto-1 3.7xto-1 2.4xto-t 2.9xlo-1 4.2xto-1 0.3 2.5xlo-t 2.8xto-t 2.7xio-t 

Nb (ppm) 3.3xl01 2.Ixl01 2.4xl02 6.9xl01 2.9xl01 2.2xl02 4.lxl01 3.9xl01 3.5x102 5.0xl01 3.7xl01 5.4xlo2 

Nd (ppm) L 2.2xlo2 1.4xlo2 L 2.lxl02 2.1xl02 L 1.5xl02 3.0xlo2 L 2.4xl02 1.9xl02 

Ni (ppm) 1.6xlo2 1.2xlo2 2.9xl01 9.2xl01 1.2xlo2 2.6xl01 1.4xlo2 1.4xl02 3.7xl01 1.4xlo2 l.lxlo2 3.0xi01 

Os (ppm) L L L L L L L L L L L L p (pet) L L 2.5 L L 3.5 L L 3.1 L L 3.2 

Pb (ppm) 3.8xl01 4.3xl01 H 3.4xl01 2.3xl01 3.6x101 2.8xl01 3.3xl01 5.3xl01 2.6xl01 4.4xl01 2.9xl01 

Pd (ppm) L L L L L L L L L L L L 

Pr(ppm) L L L L L L L L L L L L 

Pt (ppm) L L L L L L L L L L L L 

Re (ppm) L L L L L L L L L L L L 

Rh (ppm) L L L L L L L L L L L L 

Ru (ppm) L L L L L L L L L L L L 

Sb (ppm) L L L L L L L L L L L L 

Sc (ppm) 3.7xl01 3.6xl01 1.8xl01 2.8xl01 5.0xl01 l.lxl01 1.7xl01 3.6xl01 3.6xl01 3.6xl01 3.9xl01 2.8xl01 

Si (pet) 1.3xl01 2.2xl01 1.8xl01 1.3xl01 2.2xl01 1.9xl01 1.6xl01 1.9xl01 1.7xl01 1.3xl01 1.8xl01 1.8xl01 

Sm (ppm) L 2.5xl01 L L 2.3xl01 7.9xl01 L 2.2xl01 L L 2.7xl01 L 

Sn (ppm) E l.lxl01 4.0xl01 E 9.6 5.lxl01 2.5xl01 2.4xl01 l.lxlo2 E 8.7 3.7xl01 

Sr (ppm) 6.lxl01 1.8xl02 5.3xl02 2.9xl01 2.4xl02 6.5xl02 2.7xl01 2.7xl02 1.3xlol 5.lxl01 2.0xi02 I.5xl03 

Ta (ppm) L L L L L L L L L L L L 

Tb (ppm) L L L L L L L L L L L L 

Th (ppm) L l.2xl~ 1.4xlol L L L L L 2.2xl03 L L 2.0xl02 

Ti (pet) 3.9 8.lxl0" 2.3 2.0 1.0 3.6 1.2 1.3 9.8 5.1 1.1 9.0 

Tl (ppm) L L L L L L L L L L L L 

Tm (ppm) L L l.lxl01 L L 7.6 L L 1.9xl01 L L 1.7xl01 

U (ppm) L L L L L L L L L L L L 

V (ppm) 3.0xlo2 1.6xlo2 1.6xlo2 2.5xlo2 1.9xlo2 2.0xl02 1.9xlo2 2.3xlo2 2.4xl02 5.6xlo2 2.2xlo2 2.Ixl02 

W (ppm) L L L L L L L L L L L L 

y (ppm) 4.5xl01 4.4x101 1.3xl02 4.0xl01 5.2xl01 1.2xlo2 2.7x101 5.0xl01 1.5x102 4.9xl01 5.6xl01 2.0xl02 

Yb (ppm} 1.3xl01 5.1 1.9x101 7.8 7.4 1.8x101 5.5 6.8 6.5xl01 L 7.6 5.9xl01 

Zn (ppm) 3.8xlo2 2.0xl02 E 3.7xlo2 2.8xl02 E 4.7xl02 3.5xlo2 E 4.0xlo2 2.8xl0i E 

'b (ppm) 2.8xlo2 2.5x102 H 3.2xl02 6.8xlo2 H 8.8xl01 4.6xl02 H 3.0xlo2 4.1xl0 H 

10 An~lyses of Sediments from the Chukchi Sea, Alaska 
by Mark Drown. pet, percent; ppm, parts per million; L, may not be present or is less than limit of detection (Thomas, 1979); 

Sample 46-61 BS Sample 46-62, 63 BS Sample 68-88, 89, 90 BS Detection limits 

HMAG <0.6 amp >0.6 amp HMAG <0.6 amp >0.6 amp HMAG <0.6 amp >0.6 amp low High 

24 1.1 4.1 2.0 1.4 4.6 24 2.1 4.8 0.10 10,000 

3.2 4.4 4.9 3.5 7.4 4.1 5.7 8.1 3.9 .088 60 

L L L L L L L L L 100. 10,000 

L L L L L L L L L 6.8 1,500 

2.0x101 4.3x1oZ 3.0x102 6.2x101 4.8x1oZ 1.2x1ol 1.4x102 4.6x102 1.6x1oZ 3.2 460 

6.2x101 3.1x101 3.2x1ol 23x1oZ 28x1oZ 5.0xlol 1.5xloZ 2.4x103 1.7xHY' 1.5 32,000 

L L l.lx101 L L 2.6 L 1.0 2.1 1.0 680 

L L L L L L L L L 10 6,800 

3.0 7.1 1.3xl01 4.7 l.lxl01 1.3xl01 6.7 l.lx101 t.4xl01 .0014 10,000 

L L L L L L L L L 32 10,000 

L 8.3xl01 l.lx103 L 26xloZ l.lx103 27xloZ l.2x103 1.7xl03 43 20,000 

7.2x101 3.2x101 l.lx101 6.7x101 4.7x101 l.lx101 5.9x101 3.6x101 t.Sx101 1.0 22,000 

3.0xlol 1.7x1ol 7.6x102 24xl03 2.4x1ol 3.3xl02 H 3.0xl03 9.1x1oZ 1.0 6,800 

6.4xl01 8.1xt01 4.6x101 6.8x101 4.7xl01 S.3xt01 5.4xl01 4.8x101 L 1.0 1,500 

L L E L L E L S.3xl01 E 22 1,000 

L L E L L E L L E 4.6 1,000 

L L 20xto1 L L 22x1o1 L 1.7x101 28xl01 2.2 1,000 

H 7.7 3.0 H 1.9x101 1.3 1.7xl01 7.0 27 .011 34 

E 2.1xi01 t.4x101 E 1.7xl01 8.2 3.1xl01 3.Sx101 8.9 1.5 1,000 

L L 9.3x101 L L L L S.Sx101 L 32 1,000 

L L L L L L L L L 4.6 10,000 

L L 7.lxi02 L L 1.9x1ol L S.6xl02 3.Sx103 15 10,000 

L L 22x101 L L 4.4x101 L 1.3xi01 L 6.8 1,000 

L L L L L L L L L w 10,000 

L L L L L L L L L 15 10,000 

3.9x1o-• 2.4x1o-t 4.3xlo-1 4.4x1o-• L 2.2x1o-• 4.0xto-• 3.4xl0-l 3.8x1o-1 .082 13 

3.8x101 3.3xl01 4.7x1oZ 1.8x101 7.7x101 5.0x1ol 7.0x101 3.6x1oZ 7.9x1oZ 10 10,000 

E 8.0xl01 L E E L E L L 68 32,000 

L L L L L L L L L 15 1,000 

3.7 8.9 28 4.4 9.7 1.3 4.4 6.3 1.9 .0036 so 

l.lxl04 8.3x1ol 8.4x1oZ 9.4x1ol 7.6x103 3.7x1oZ 1.5xl04 4.9xlol 5.2x102 1.0 460,000 

E L L E 5.3 L 7.6 3.9 L 1.0 1,000 

28xto-1 3.Sx1o-• 4.4xto-• 3.4x10-t 2.6x1o-• 2.5xto-1 5.3x1o-• 5.3xlo-1 L .0029 11 

1.3x102 1.3x101 3.1xloZ 5.6xl01 6.2x1o1 6.6x1oZ 4.9x101 l.Oxlol 5.9x102 6.8 1,000 

L L 4.2xlol L 6.3xl01 2.9x102 L 2.4x1oZ 5.4xloZ 32 10,000 

1.8xloZ l.Oxl02 5.4x101 20x1oZ 1.6x102 3.6x101 1.4x102 1.2x1ol 5.8x101 1.5 15,000 

L L L L L L L L L 15 6,800 

L L 4.4 L L 3.2 L 9.4xto-• 2.9 .16 16 

4.4x101 23x101 7.5xl01 5.2x101 23x101 s.0x101 27x101 6.6x101 6.1x101 6.8 1,000 

L L L L L L L L L 1.0 4,600 

L L L L 1.2x102 L L L L 100 1,000 

L L L L L L L L L 2.2 10,000 

L L L L L L L L L 10 10,000 

L L L L L L L L L 2.2 10,000 

L L L L L L L L L 2.2 10,000 

L L L L L L L L L 68 10,000 

3.8xl01 25x101 3.0x101 3.4xl01 5.4xi01 3.9xt01 3.5xl01 3.9x101 5.8x101 1.0 10,000 

9.1 2.3x101 20xl01 t.3xl01 25xl01 1.9x101 1.6xl01 24x101 2.2xl01 .0099 73 

L L 26xloZ L L L L L L 10 1,000 

E 1.7x101 1.2x1ol E L 6.8x101 2.6x101 3.3xl01 1.7x102 4.6 10,000 

4.4xl01 4.2xt01 5.9x1oZ 4.txto1 22x102 1.7x1ol 7.6x101 6.7x1oZ 1.8x1ol 1.0 320,000 

L L L L L L L L L 320 10,000 

L L L L L L L L L 32 1,000 

L L 1.5x1ol L L 6.7x10~ L L 2.5xl02 46 10,000 

1.2xl01 5.7xto-• 6.1 7.3 1.5 1.6x10 4.5 4.0 1.7x101 .0053 77 

L L L L L L L L L 10 10,000 

L L 1.6xl01 L L 25x101 L L 3.4xl01 4.6 1,000 

L L L L L L L L L 220 10,000 

8.4x1oZ 1.5x1oZ 28x1oZ 9.8xloZ 25x1oZ 4.5xloZ 3.2xlol 28xloZ 3.2xlol 1.0 1,000 

L L L L L L L L L 15 10,000 

3.1xl01 7.0xt01 23x1oZ 4.4xt01 7.5xl01 E 4.2xto1 9.4xl01 E 1.5 10,000 

L 1.3xl01 S.4xl01 L 8.6 9.1x101 7.6 22x1o1 1.2x1ol .15 1,000 

4.4x1oZ 1.9x1oZ E 6.3x1oZ 22x1ol E 3.9x1oZ 22x1ol E 10 10,000 

6.6xloZ S.4xi01 H 3.8x1oZ 20x1ol H 1.4xloZ 22x1ol H 3.2 22,000 

Tables 3 and 4 11 
Table 4. Statistics of major and minor elements detected in designated heavy-mineral fractions of samples 

from the Chukchi Sea, Alaska 

[Elements detected by emission spectrographic analysis (table 3)] 

A. Strongly paramagnetic/ferromagnetic heavy-mineral B. Moderately magnetic 0.0-amp to 0.6-amp heavy-mineral 

fraction separated by hand magnet fraction separated by electromagnet-Continued 

fie- Mini- Maxi- Mean Variance Standard Ele- Mini- Maxi- Mean Variance Standard 

ment mum mum deviation ment mum mum deviation 

Major elements, values in percent Minor elements, values in parts per million-Conlinued 

Si 9.1 16.0 13.3 5.4 2.3 Ho 6.8 13.0 7.7 5.5 2.3 AI 2.8 5.7 4.2 1.6 1.3 La 33.0 360.0 184 l.lx104 107 Fe 17.0 24.0 22.4 8.0 2.8 Mn 4,900.0 8,400.0 6,871 l.6xl06 l.3xl03 

Mg 3.5 4.6 4.0 0.2 .4 Mo 1.0 5.3 3.2 2.1 1.5 Ca 2.3 6.7 3.8 2.5 1.5 Nb 13.0 100.0 43.0 874 29.6 

Na .3 .4 .3 3.8x1o-3 6.2x1o-2 Nd 32.0 240.0 165 7.4xl03 86.2 K .4 .5 .4 ux~o-3 3.3xl0-2 Ni 100.0 160.0 124.3 395.2 19.9 Ti 1.2 12.0 5.1 13.2 3.6 Pb 23.0 66.0 37.1 235.8 15.4 

Pr 100.0 150.0 110.0 366.7 19.2 Minor elements, values in parts per million Sc 25.0 54.0 39.9 92.5 9.6 

Ag 1.5 2.4 2.0 9.6x10-2 0.3 Sm 10.0 32.0 24.4 56.3 1.5 B 6.8 200.0 78.8 4.7x103 68.5 Sn 4.6 33.0 15.4 100 10.0 Ba 62.0 250.0 144 5.1x103 72.1 Sr 42.0 670.0 260 3.8x104 195 Co 42.0 72.0 57.9 114 10.7 Th 46.0 150.0 102 963 31.0 Cr 1,700.0 6,800.0 3,114 2.9xl06 1,714 v 150.0 280.0 211 2.3x103 47.4 

Cu 33.0 71.0 56.4 267 16.3 y 44.0 94.0 63.0 309 17.6 Ge 4.6 15.0 6.1 15.4 3.9 Yb 5.1 22.0 10.0 33.6 5.8 Hf 15.0 150.0 92.1 5.2x103 72.2 Zn 190.0 350.0 249 3.3x103 57.3 La 10.0 70.0 34.6 361 19.0 Zr 54.0 2,200.0 M5 7.5xl05 867 Mn 9,200.0 15,000.0 11,514 4.2x106 2,039 

Nb 33.0 130.0 61.1 l.Ox1cf 32.4 c. Nonmagnetic >0.6-amp heavy-mineral 

Ni 92.0 200.0 150 l.2x103 34.6 fraction separated by electromagnet Pb 26.0 52.0 37.1 107 10.3 

Sc 17.0 38.0 32.1 55.1 7.4 Major elements, values in percent Sr 27.0 76.0 47.0 304 17.4 

v 190.0 980.0 491 9.7xl03 311 Si 14.0 22.0 18.3 6.2 2.5 y 27.0 49.0 39.7 62.6 7.9 AI 1.1 4.9 2.9 2.2 1.5 Yb 5.5 13.0 7.8 5.9 2.4 Fe 1.0 3.0 1.7 .7 .8 Zn 370.0 630.0 440 8.3x103 90.9 Mg .6 2.8 1.2 .7 .9 Zr 88.0 660.0 310 3.4x104 186 Ca 3.8 14.0 9.1 19.2 4.4 

B. Moderately magnetic 0.0-amp to 0.6-amp heavy-mineral Na .2 .4 .3 7.7x1o-3 8.8x10-2 

K .2 .4 .3 8.3x10-3 9.1x10-2 

fraction separated by electromagnet Ti 2.3 17.0 9.1 32.7 5.7 p 2.5 4.4 3.3 .4 .6 

Major elements, values in percent 

Minor elements, values in parts per million 

Si 18.0 25.0 21.9 6.5 2.5 

AI 4.4 8.1 6.6 2.0 1.4 Ag 1.4 5.9 4.1 2.3 1.5 Fe 7.0 19.0 13.7 21.2 4.6 B 74.0 300.0 139.6 5.9x103 76.9 

Mg 6.0 9.7 8.0 2.0 1.4 Ba 3,200.0 21,000.0 11,443 43.6xl06 6.6xl03 

Ca 6.9 11.0 8.9 3.1 1.8 Be 1.0 11.0 3.5 12.9 3.6 

Ce 480.0 1,700.0 1,037 l.4xl05 371 

Na .3 .5 .4 9.5xl0-3 9.7x10-2 

K .2 .3 .3 4.0x1o-3 6.4xl0-2 Co 6.6 15.0 9.6 9.4 3.1 

Ti .6 4.0 1.5 1.3 1.2 Cr 210.0 910.0 514 5.7xl04 239 

p 6.8x10"2 .9 .2 .1 .3 eu• 14.0 54.0 38.0 269 16.4 

Eu 9.0 28.0 17.7 46.5 6.8 

Minor elemmts, values in parts per million Ga 4.3 14.0 7.6 10.9 3.3 

Ag .8 2.1 1.2 0.2 0.5 Hf 300.0 3,500.0 1,487 10.9x105 1,045 

B 180.0 480.0 391 l.lx104 105 La 170.0 790.0 416 4.7x104 216 Ba 31.0 2,400.0 523 6.9x105 832 Mn 180.0 840.0 409 5.0x104 223 

Ce 83.0 1,200.0 513 1.2x105 351 Nb 220.0 660.0 416 3.2x104 178 

Co 32.0 48.0 38.3 42.6 6.5 Nd 140.0 540.0 299 2.0x104 140 

Cr 1,700.0 3,000.0 2,286 3.1x105 558 Ni 26.0 58.0 38.6 158 12.6 

Cu 11.0 81.0 52.2 655 25.6 Sc 11.0 58.0 31.4 233 15.3 

Dy 22.0 53.0 26.4 137 11.7 Sn 37.0 170.0 85.1 2.5x103 49.8 

Er 4.6 100.0 18.2 1.3x103 36.1 Sr 530.0 1,800.0 1,153 3.0xl05 551 Eu 2.2 17.0 4.7 30.4 5.5 Th 46.0 2,200.0 898 6.6x10S 813 

Ga 15.0 35.0 22.1 64.1 8.0 Tm 7.6 34.0 18.5 77.7 8.8 Gd 32.0 55.0 35.3 75.6 8.7 v 160.0 450.0 266 9.4x103 96.9 Ge 4.6 15.0 6.1 15.5 3.9 y• 120.0 230.0 166 2.2x103 47.2 Hf 15.0 560.0 141 4.1x104 202 Yb 18.0 120.0 60.9 l.3x103 36.7 

*Statistics based on 5 samples. 

12 Analyses of Sediments from the Chukchi Sea, Alaska 
SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

Periodicals 

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenters (issued monthly). 

Technical Books and Reports 

Professional Papers are mainly comprehensive scientific reports of 

wide and lasting interest and importance to professional scientists and engineers. Included are reports on the results of resource studies and of 

topographic, hydrologic, and geologic investigations. They also include 

collections of related papers addressing different aspects of a single scientific topic. 

Bulletins contain significant data and interpretations that are of lasting scientific interest but are generally more limited in scope or 

geographic coverage than Professional Papers. They include the results 

of resource studies and of geologic and topographic investigations; as well 

as collections of short papers related to a specific topic. 

Water-Supply Papers are comprehensive reports that present significant interpretive results of hydrologic investigations of wide interest 

to professional geologists, hydrologists, and engineers. The series covers 

investigations in all phases of hydrology, including hydrogeology, 

availability of water, quality of water, and use of water. 

Cb'culars present administrative information or important scientific 

information of wide popular interest in a format designed for distribution 

at no cost to the public. Information is usually of short-term interest. 

Water-Resources Investigations Reports are papers of an interpretive nature made available to the public outside the formal USGS publications series. Copies are reproduced on request unlike formal USGS 

publications, and they are also available for public inspection at 

depositories indicated in USGS catalogs. 

Open-File Reports include unpublished manuscript reports, maps, 

and other material that are made available for public consultation at 

depositories. They are a nonpermanent form of publication that may be 

cited in other publications as sources of information. 

Maps 

Geologic Quadrangle Maps are multicolor geologic maps on 

topographic bases in 7 1/2-or 15-minute quadrangle formats (scales mainly 1 :24,000 or 1 :62,500) showing bedrock, surficial, or engineering geology. Maps generally include brief texts; some maps include structure 

and columnar sections only. 

Geophysical Investigations Maps are on topographic or planimetric 

bases at various scales; they show results of surveys using geophysical 

techniques, such as gravity, magnetic, seismic, or radioactivity, which 

reflectsubsurfacestructuresthatareofeconomicorgeologicsignificance. 

Many maps include correlations with the geology. 

Miscellaneous Investigations Series Maps are on planimetric or 

topographic bases of regular and irregular areas at various scales; they 

present a wide variety of format and subject matter. The series also includes 7 1/2-minute quadrangle photo geologic maps on planimetric bases 

which show geology as interpreted from aerial photographs. Series also 

includes maps of Mars and the Moon. 

Coal Investigations Maps are geologic maps on topographic or 

planimetric bases at various scales showing bedrock or surficial geology, stratigraphy, and structural relations in certain coal-resource areas. 

Oil and Gas Investigations Charts show stratigraphic information 

for certain oil and gas fields and other areas having petroleum potential. 

Miscellaneous Field Studies Maps are multicolor or black-andwhite maps on topographic or planimetric bases on quadrangle or irregular areas at various scales. Pre-1971 maps show bedrock geology 

in relation to specific mining or mineral-deposit problems; post-1971 

maps are primarily black-and-white maps on various subjects such as 

environmental studies or wilderness mineral investigations. 

Hydrologic Investigations Atlases are multicolored or black-andwhite maps on topographic or planirnetri(, bases presenting a wide range 

of geohydrologic data of both regular and irregular areas; principal scale 

is 1:24,000 and regional studies are at 1:250,000 scale or smaller. 

Catalogs 

Permanent catalogs, as well as some others, giving comprehensive listings of U.S. Geological Survey publications are available under 

the conditions indicated below from the U.S. Geological Survey, Books 

and Open-File Reports Section, Federal Center, Box 25425, Denver, 

CO 80225. (See latest Price and Availability List) 

"Publications of the Geological Survey, 1879- 1961" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiche. 

"Publications of the Geological Survey, 1962- 1970" may be purchased by mail and over the counter in paperback book form and as a 

set of microfiChe. 

"Publications of the U.S. Geological Survey, 1971-1981" may be 

purchased by mail and over the counter in paperback book form (two 

volumes, publications listing and index) and as a set of microfiche. 

Supplements for 1982,1983, 1984, 1985,1986, and for subsequent 

years since the last pennanent catalog may be purchased by mail and 

over the counter in paperback book form. 

State catalogs, "List of U.S. Geological Survey Geologic and 

Water-Supply Reports and Maps For (State)," may be purchased by mail 

and over the counter in paperback booklet fonn only. 

"Price and Availability List or U.S. Geological Survey Publications," issued armually, is available free of charge in paperback booklet fonn only. 

Selected copies or a monthly catalog "New Publications of the U.S. 

Geological Survey" available free of charge by mail or may be obtained 

over the counter in paperback booklet form only. Those wishing a free 

subscription to the monthly catalog "New Publications of the U.S. 

Geological Survey" should write to the U.S. Geological Survey, 582 

National Center, Reston, VA 22092. 

Note.--Prices of Government publications listed in older catalogs, 

armouncements, and publications may be incorrect. Therefore, the 

prices charged may differ from the prices in catalogs, announcements, 

and publications.