Quaternary Stratigraphy and 

Paleoceanography of the 

Canada Basin, Western Arctic Ocean 

I 

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Quate:mary Stratigraphy and 

Paleoceanography of the 

Canad.a Basin, Western. Arctic Ocean 

By Richard Z. Poore, Scott E. Ishman, R. Lawrence Phillips, and David H. McNeil 

U.S. GEOLOGICAL SURVEY BULLETIN 2080 

Climate and paleoceanography of the western 

Arctic Ocean for the last 1 million years interpreted 

from four marine sediment cores 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1994 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary 

U.S. GEOLOGICAL SURVEY 

ROBERT M. HIRSCH, Acting Director 

For sale by U.S. Geological Survey, Map Distribution 

Box 25286, MS 306, Federal Center 

Denver, CO 80225 

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. 

Published in the Eastern Region, Reston, Va. 

Manuscript approved for publication December 7, 1993. 

Library of Congress Cataloging in Publication Data 

Quaternary stratigraphy and paleoceanography of the Canada Basin, western Arctic 

Ocean I by Richard Z. Poore ... [et al.]. 

p. em. - (U.S. Geological Survey bulletin ; 2080) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.3:2080 

1. Geology, Stratigraphic-Quaternary. 2. Paleoceanography-Canada Basin. 

I. Poore, Richard Z. II. Series. 

QE75.B9 no. 2080 

[QE696] 

557.3 s-dc20 

[551.46'083327] 93-50143 

CIP 
CONTJ~NTS 

Abstract........................................................................................... 1 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Lithostratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Unit J .......................................... ............................................. 4 

Unit M...................................................................................... 4 

Units L, K, and I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Magnetostratigraphy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Foraminifers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Paleoceanography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Glacial-Interglacial Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Deep Waters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

FIGURES 

1. Maps showing location of North wind Ridge in western Arctic Ocean and coring sites discussed in text........ 2 

2. Diagram showing coarse-fraction data and assignment to Arctic lithostratigraphic units for Northwind 

Ridge cores 9, 5, 3, and 7 and central Arctic cores 228 and 270 . .. .. . .. .. . . .. . .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. . .. 5 

3. Photograph showing brown beds and color banding in parts of N orthwind Ridge cores 9, 5, 3, and 7.......... 6 

4. Diagram of magnetostratigraphy, lithostratigraphy, and foraminifer abundance data for North wind 

Ridge core 5 and oxygen-isotope stages of the deep sea.................................................................. 8 

5. Diagram showing foraminifer abundance data for Northwind Ridge cores 9, 5, 3, and 7.................. .... .. .. 9 

6, 7. Graphs showing abundance variation of selected benthic foraminifers in Northwind Ridge cores: 

6. Core 5.................. ................ ........ .. ... ...... ... .. .... ...... .. .. . . .. ... ... .. ... ..... .. ....... ... .. .... .. .......... 13 

7. Core 3.................. ........................ .. ..... ... .... .. .... .. .. . . .. .. . . .. .. .. .. .. ... . . ....... ..... ... .. .... .. .......... 14 

TABLES 

[Tables 2 and 3 follow References Cited] 

1. Core designation, core length, water depth, and coordinates for Northwind Ridge cores 9, 5, 3, and 7 

from the western Arctic Ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

2, 3. Benthic foraminifer abundance, in percent, in samples from Northwind Ridge cores: 

2. Core 5.... .......... ...... .......... ......... ... .. ..... ... .... .. .... .. .. . . ..... ... ....... ... .. ... . .......... .. .... .. .... .. ...... 18 

3. Core 3.... .......... ................ ........ ....... ... .... .. ... . .... .. .. .. ..... ... . . ..... ... .. ..... ..... .. ..... .... ............. 27 

III 
IV CONTENTS 

CONVERSION FACTORS 

Multiply By To obtain 

Length 

micrometer (JJ.m) 0.000039 inch 

millimeter (mm) 0.0394 inch 

centimeter (em) 0.3937 inch 

meter (m) 3.281 foot 

Mass 

gram (g) 0.0353 ounce avoirdupois 

Age designation. - Carbon-14 dates are expressed as yr B. P. , meaning years before 

present (A.D. 1950). 
Quaternary Stratigraphy and Paleoceanography of the 

Canada Basin, Western Arctic Ocean 

By Richard Z. Poore, 1 Scott E. Ishman, 1 R. Lawrence Phillips, 2 and David H. McNeie 

ABSTRACT 

Lithologic, paleontologic, and paleomagnetic analyses 

of sediment cores from N orthwind Ridge in the western 

Canada Basin provide a stratigraphic framework for interpreting the upper Quaternary paleoceanographic record of 

the western Arctic Ocean. Analyses of the cores, which 

were taken over a depth range of 945 to 3,513 m, reveal 

distinct cycles in the abundance of planktic foraminifers that 

we interpret as glacial-interglacial cycles. Variations in 

preservation of foraminifers and changes in benthic foraminifer assemblages through time and along the depth 

transect show that the carbonate compensation depth 

became deeper during successive interglacial stages of the 

late Quaternary. The abrupt abundant appearance of Oridorsalis in benthic assemblages between 3,513 and 945 m 

depth during an interglacial stage that we correlate with 

oxygen-isotope stage 9 marks the development of near 

modem deepwater structure in the western Arctic. 

INTRODUCTION 

The Arctic Ocean is an extremely important component of the Earth's climate system, yet the paleoceanographic and paleoclimatic history of the Arctic is still poorly 

known and controversial. Documenting the Pliocene to 

Quaternary history of the Arctic Ocean has been hampered 

by lack of adequate material for study and by the perennial 

ice cover that limits access to many areas of the Arctic. 

Most coring in the central and western Arctic has been done 

from floating ice stations that cannot be directed toward a 

particular area or objective. In general, only short piston 

and gravity cores are available, and most cores from 

1

U.S. Geological Survey, Reston, VA 22092. 2

U.S. Geological Survey, Menlo Park, CA 94025. 3

Institute of Sedimentary and Petroleum Geology, 3303 33rd St., 

NW, Calgary, Alberta T2L 2A 7, Canada. 

topographic highs in the central and western Arctic recovered sedimentary sections with extremely low average 

accumulation rates (about 1 to 2 mm/1 ,000 yr; for example, 

see Clark and others, 1980; Scott and others, 1989). Age 

and environmental interpretations of these cores are complicated by the low resolution of the records. The cores 

available from the deep Canada Basin sampled Holocene 

turbidites (Hunkins and Kutschale, 1967; Campbell and 

Clark, 1977; Goldstein, 1983), for which sediment accumulation rates range from 4 to 462 mm/1 ,000 yr, with an 

average of 83 mm/1,000 yr (Campbell and Clark, 1977). 

However, the turbidites contain much reworked material, 

and interpreting a paleoceanographic record from them is 

very difficult. 

The U.S. Geological Survey obtained a suite of piston 

cores in 1988 from the U.S. Coast Guard Cutter Polar Star 

in the area of Northwind Ridge, which is a prominent 

feature extending from the Chukchi Sea continental slope 

into the Canada Basin of the western Arctic Ocean (fig. 1A, 

B). The cruise was part of an ongoing geologic sampling 

and geophysical program designed to understand the geologic evolution and oceanographic history of the western 

Arctic Ocean. Initial examination of the 1988 Polar Star 

cores indicated that they contained a relatively complete 

record of the last million years and that accumulation rates 

in some cores were higher (>4 mm/1 ,000 yr) than those for 

existing Arctic cores collected from topographic highs. 

Thus, these cores preserve a more detailed, yet still condensed, paleoclimatic and paleoceanographic record of the 

western Arctic Ocean. 

This study presents the stratigraphy and environmental 

interpretations of four cores recovered from the crest and 

east flank (Northwind Escarpment) of Northwind Ridge in 

1988 (fig. 1C; table 1). The cores form a transect that 

extends from 945 m down to 3,513 m depth. Cores 9 and 5 

are from near the crest of Northwind Ridge on opposite 

sides of a central depression that extends along the ridge 

axis. Cores 3 and 7 are from the Northwind Escarpment. 

Cores 9 and 5 recovered relatively long and apparently 

undisturbed sections-626 and 476 em, respectively. The 

sections recovered in cores 3 and 7 are complicated by 
2 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

8 

0 200 KILOMETERS 

Chukchi Sea 

Alaska 
INTRODUCTION 

c 

20 KILOMETERS 

~-J Figure 1. Location of study area (A, B) and four coring sites on Northwind Ridge in western Arctic 

Ocean (C). Bathymetry contours in meters. A, Setting of the study area (at star) near the North Pole. Base 

map modified from MapArt Update 92 (MicroMaps Software, Lambertville, N.J.). B, Location of the 

study area on North wind Ridge from which the U.S. Geological Survey collected the four cores described 

in this report. CESAR indicates area where cores were taken during the Canadian Expedition to Study the 

Alpha Ridge (CESAR) (Aksu, 1985; Scott and others, 1989). C, Location of Northwind Ridge coring 

sites (solid dots) discussed in text. B and C modified from Phillips and others (1992, fig. 1). 

Table 1. Core designation, core length, water depth, and coordinates for Northwind Ridge cores 

9, 5, 3, and 7 from the western Arctic Ocean. 

Core designation Core length Water depth Coordinates 

Full Brief (em) (m) Latitude (N.) Longitude (W.) 

PI-88-AR-P9 9 626 945 75°01.38' 158°14.23' 

PI-88-AR-P5 5 476 1089 74°37.35' 157°53.04' 

PI-88-AR-P3 3 581 1909 74°35.60' 157°39.59' 

PI-88-AR-P7 7 536 3513 74°37.76' 157°23.17' 

3 
4 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

internal erosional unconformities. However, most of core 3 

and the upper part of core 7 do not contain discernible 

sediment gaps (Phillips and others, 1992). Pleistocene 

sediments recovered from Northwind Ridge consist of 

unconsolidated, interbedded mud, silty mud, sandy mud, 

and gravelly sandy mud. The cores exhibit distinct color 

banding due to intercalation of pinkish-white to white, 

clast-rich layers, dark-brown muddy and sandy mud beds, 

and gray to tan muds and silty muds. Calcareous microfossils are concentrated in the dark-brown beds, most of which 

are bioturbated and contain variable amounts of ice-rafted 

sediment. 

ACKNOWLEDGMENTS 

We thank Kevin Foley (U.S. Geological Survey, 

USGS) for technical assistance throughout this study and 

David L. Clark (University of Wisconsin) for discussions 

about the lithostratigraphy of our cores. The manuscript 

benefited from comments by Debra Willard, Paula Quinterno, and Arthur Grantz (all of USGS). We thank Meyer 

Rubin (USGS, Reston, Va.) for preparing graphite targets 

used for carbon-14 dating of upper layers of cores 9, 5, and 

3. Dating of samples from core 5 was done at the National 

Science Foundation Accelerator Facility for Radioisotope 

Analyses at the University of Arizona, Tucson, Ariz. 

Dating of samples from cores 9 and 3 was done at the 

Center for Accelerator Mass Spectrometry, Lawrence 

Livermore National Laboratory, Livermore, Calif. 

LITHOSTRATIGRAPHY 

Clark and others ( 1980) defined informal standard 

lithostratigraphic units for the Arctic based on analyses of 

cores taken from the T3 Ice Island. These standard lithostratigraphic units have been recognized and used for 

correlation throughout the central and western Arctic Basin 

(Morris and Clark, 1986; Darby and others, 1989; Scott and 

others, 1989). The lithostratigraphic units of Clark and 

others (1980) have been identified in the Northwind Ridge 

sedimentary sequence (Phillips and others, 1992) and form 

a primary means for correlating between cores. Sediment 

texture, pinkish-white to white, clast-rich beds, and darkbrown muddy and sandy mud beds are important features 

for identifying these lithostratigraphic units. Figure 2 shows 

the percentage of coarse material (>63 J.Lm) in Northwind 

Ridge cores and sand-sized content of selected cores used 

by Clark and others (1980) to define the lithostratigraphy 

for the central and western Arctic Ocean. The coarse 

material in Northwind Ridge cores is mostly sand. Detailed 

logs and photographs of cores 9, 5, 3, and 7 were provided 

by Phillips and others (1992). 

UNIT J 

Unit J, with its upper and lower sand peaks, is one of 

the keys to identifying the lithostratigraphic sequence. In 

cores from the central Arctic, the lower sand peak of unit J 

is characterized by a thin, but well-defined, pinkish-white, 

clast-rich layer (PW1 of Clark and others, 1980), and the 

upper sand peak typically contains scattered pinkish-white 

clasts (pink-white clast interval of Clark and others, 1980). 

At Northwind Ridge, near the edge of the Arctic Basin, 

PW 1 is well developed at the base of unit J, and the 

pinkish-white clast interval is present as a well-defined bed 

at the top of unit J in cores 5 and 7. Pinkish-white clasts are 

not present in the coarse-fraction peak at the top of unit J in 

core 3. An unconformity occurs between units J and L in 

core 3, and the top of J and all of unit K are missing (see 

Phillips and others, 1992). The lower coarse-fraction peak 

and PW1 are well represented in core 3 (fig. 2). 

UNITM 

Unit M is another key unit. As defined by Clark and 

others (1980), unit M commonly has an upper and a lower 

sand peak; the lower peak is marked by a pinkish-white, 

clast-rich layer. They noted that this clast-rich layer (PW2) 

is commonly distorted and intermixed with the surrounding 

sediment through an interval of up to 15 em. In the 

relatively expanded sections recovered from Northwind 

Ridge, PW2 has been identified as two separate 1- to 2-

cm-thick, clast-rich beds approximately 5 to 10 em apart. 

Following consultation with D.L. Clark, the lower limit of 

unit Min Northwind Ridge cores has been placed at the top 

of the first dark-brown, foraminifer-rich muddy sand bed 

just below PW2. Thus, in Northwind Ridge cores, PW2 

occurs near the bottom but not at the base of unit M. D.L. 

Clark (oral commun., 1993) placed the base of unit M on 

top of the brown bed below PW2 because the underlying 

unit L always has a dark-brown bed at its top. The split 

PW2 in our cores is readily traced among cores 9, 5, 3, and 

7 (fig. 3). The split PW2 shows up as a double peak in the 

coarse-fraction plots for cores 9, 3, and 7 (fig. 2). No 

double peak is evident in the coarse-fraction plot of core 5 

because of burrowing and the closer spacing of the PW2 

beds (fig. 2). 

The upper sand peak of unit M in central Arctic cores 

commonly contains one or two white layers that have been 

designated W2 and W3 (Clark and others, 1980; Minicucci 

and Clark, 1983). The white, clast-rich beds W2 and W3 

are present in all four of our cores. The upper and lower 

coarse-fraction peaks, the presence of W2 and W3, and the 

split PW2 allow ready identification of unit M in cores 9, 5, 

3, and 7 (see figs. 2 and 3). 
Core 228 Core 270 

Depth 

(em) 0--.-----... 

10 20 30 

Weight percentage 

63-2,000 ~tm 

10 20 30 

Weight percentage 

63-2,000 Jlm 

EXPLANATION 

Standard Arctic 

I ithostratig raph ic 

units Brown beds 

M c=J 

L c=J 

K .. 

J~ 

c=J 

~ 

Core 9 

'"""--------~% 

10 20 30 

Weight percentage 

>63 1Jm 

Core 5 

PW2 

~PW1 

10 20 30 

Weight percentage 

>63 1J m 

Core 3 

Depth 

(em) o --=--= 

100 

300 

400 

10 20 30 

Weight percentage 

>631Jm 

Core 7 

Depth 

em ~ 

100 

200 

300 

400 10 20 30 

Weight percentage 

>631Jm 

'}

multiple 

new pink 

beds 

Figure 2. Coarse-fraction data (weight percentage of sample that is > 63 j.Lm) and assignment to 

Arctic lithostratigraphic units for Northwind Ridge cores 9, 5, 3, and 7. Flow-in problems complicate 

the interpretation of the bottom of core 3, and so this part is not shown; core 7 was cut off at an 

erosional contact within unit I. Sand-fraction data (weight percentage 63-2,000 j.Lm) and lithostratigraphic assignments for central Arctic cores 228 and 270 are from Clark and others (1980). 

Coarse-fraction data for Northwind Ridge cores are from Phillips and others (1992). See text for 

discussion for lithostratigraphic assignments. White and pinkish-white, clast-rich beds of Clark and 

others (1980) are indicated by W3, W2, PW2, PWl, and PW clast for cores 9, 5, 3, and 7. NPWB is 

new clast unit identified in cores 9, 5, and 3. Clark and others (1980) did not plot the positions of 

clast-rich beds for cores 228 and 270, and so they are not indicated on the diagram for those cores. 

Cores 228 and 270 are plotted at expanded scales to clarify the condensed sections in those cores. 

l' 

:::::3 

X 

0 

en 

...., 

...., 

~ 

a 

~ 'i:l 

X 

>-< 

VI 
6 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

PW2 

Unit M 

Unit L 

PW2 

I 

Unit M 

Unit L 

Figure 3. Parts of Northwind Ridge cores 9, 5, 3, and 7. In each core, the two light bands are the split PW2 bed, which 

is clast rich. Centimeter scales are visible along the cores. 
FORAMINIFERS 7 

UNITS L, K, AND I 

A distinct, 20- to 25-cm-thick, pinkish-white to white, 

clast-rich bed, not recognized in previous Arctic cores, 

occurs within the interval we have assigned to unit L. This 

pinkish-white to white, clast-rich layer, labeled NPWB on 

figure 2, occurs near the middle of unit L in cores 9, 5, and 

3. An alternative stratigraphy for our cores would be to 

interpret NPWB as PW2 and to consider the split, clast-rich 

beds discussed above as a new clast-rich unit. Interpreting 

NPWB as PW2 would change the lower boundary of unit M 

but would not change correlation among our cores. 

Several thin, pink or pinkish-white, clast-rich beds are 

present in the lower part of unit L in core 7. However, unit 

L in core 7 is complicated by one or more unconformities, 

and the multiple pink to pinkish-white beds seen in core 7 

were not observed in any of our other cores from Northwind 

Ridge. The multiple pink to pinkish-white beds in unit L of 

core 7 may represent very local depositional features. 

Units L, K, and I do not have distinctive textural 

signatures like units M and J but can be identified from 

other characteristics and stratigraphic position. As delineated by Clark and others (1980), unit L has a high but 

variable sand content, and foraminifers can be abundant in 

the middle to upper part of L but are rare in the lower part 

of L. Unit K is characterized by a lower sand content than 

units J or L and commonly contains abundant planktic 

foraminifers. 

Unit L, as identified at Northwind Ridge, shows a high 

but very variable coarse-fraction content. Dark-brown, 

foraminifer-rich beds occur in the upper part of L in cores 9, 

5, and 3. Foraminifers are essentially absent below the top 

of unit L in core 7 because of dissolution (see discussion 

below). The expanded section recovered in core 9 ends in 

unit L. 

Unit K is distinguished from units Land J in core 5 by 

the presence of upper and lower dark-brown, foraminiferrich beds and a slightly lower average coarse-fraction 

content. Unit K is distinguished from units L and J in core 

7 by a distinctly lower coarse-fraction content. Unit K is not 

present in core 3 . The top of unit J in core 3 contains 

slightly inclined laminated beds that are truncated at the 

contact between J and L. Slumping or erosion probably 

removed unit K from the sequence recovered in core 3. 

Unit I was identified in cores 5, 7, and 3 primarily on 

the basis of stratigraphic position below unit J. Unit I is 

complicated by flow-in problems in core 3 and is not plotted 

on figure 2. 

MAGNETOSTRATIGRAPHY 

Paleomagnetic data from core 5 (Poore and others, 

1993) indicate that the polarity reversal horizon representing the Matuyama-Brunhes boundary occurs within unit K, 

and that the Jaramillo normal polarity event is in the lower 

part of unit J to the upper part of unit I (see fig. 4). These 

results match compilations of paleomagnetic results from 

Arctic cores, which show that the Matuyama-Brunhes 

polarity reversal horizon typically falls within the middle 

part of unit K and that the Jaramillo is associated with the 

lower part of unit J (for example, see Darby and others, 

1989). 

FORAMINIFERS 

The abundance of foraminifers (in number per gram 

dry weight) and a census of planktic foraminifers were 

obtained from the > 150-J.Lm size fraction of samples from 

cores 9, 5, and 3 and the upper part of core 7 (fig. 5). We 

selected the > 150-J.Lm size fraction to make our planktic 

foraminifer census data consistent with published modern 

core-top data (for example, Kipp, 1976; Kellogg, 1977) and 

to minimize problems of juvenile and unidentifiable specimens in our census data. For samples containing abundant 

planktic foraminifers > 150 J.Lm, a split of the total sample 

containing approximately 300 planktic specimens was used 

for the faunal census and for calculating abundances of 

planktic and benthic foraminifers. For samples containing 

::;300 planktic foraminifers, all planktic and benthic foraminifers were picked from the > 150-J.Lm fraction and used to 

calculate foraminifer abundances and for the planktic 

foraminifer census. Inspection of the 63- to 150-J.Lm fraction of our samples indicates that the abundance data for the 

> 150-J.Lm size fraction accurately reflect changes in abundances of foraminifers in the >63-J,Lm fraction. 

Census data for planktic foraminifers were tabulated 

by Foley and Poore (1991, 1993). These data show that 

Neogloboquadrina pachyderma constitutes over 90 percent 

of the planktic assemblages in all samples; left-coiling 

Neogloboquadrina pachyderma usually exceeds 95 percent 

of the N. pachyderma population. The remainder of the 

fauna consists of intergrades between N. pachyderma and 

N. dutertrei (P-D intergrade of Kipp, 1976; dupac of Foley 

and Poore, 1991). Inspection of the 63- to 150-J,Lm fraction 

shows that Globigerina egelida and Turborotalita quinqueloba are present in a few samples from the upper part of unit 

L and from unit M; however, Neogloboquadrina pachyderma is still the dominant member of the assemblages in 

the 63- to 150-J.Lm size fraction. We observed no first or last 

occurrences of planktic foraminifers in the Northwind 

Ridge cores that would be considered standard biostratigraphic events. 

Previous studies of benthic foraminifers in deep-sea 

sediments have used a variety of methods and size fractions. 

Our examination of benthic foraminifers in Northwind 

Ridge cores incorporated different faunal census methods as 

part of an effort to find an optimum procedure for future 

work. Splits of approximately 300 specimens >63 J.Lm were 
8 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

Core 5 

Standard Arctic 

Polarity lithostratigraphic 

zones units Depth 

Planktic foraminifers 

>150 Jll1l per gram 

Oxygen-isotope stages 

olBQ (std. dev. units; Imbrie 

and others, 1984) 

(em) 0 6000 

5,186 yr B.P."Fzz::tli:::a;llli!l::::::::!==-----' 

2 0 -1 -2 

7,800 yr B.P. 

? 

? 

9 

'\ 11 

200 (/) 

Q) (/) ..c 

c "0 ::J Q) 

05 ..0 

c 

$: 

0 

.0 

~ ) 300 

benthic foraminifers 

400 

~ benthic foraminifers 

500 -t--t-r.....--,r-r-"'"1 

0 300 

Benthic foraminifers 

>150 Jll1l per gram 

Figure 4. Magnetostratigraphy, lithostratigraphy, and foraminifer abundance 

data for core 5 and relation of foraminifer abundance to generalized deep-sea 

oxygen-isotope record. Composite deep-sea oxygen-isotope record is aligned so 

that the Matuyama-Brunhes polarity reversal horizon in core 5 coincides 

approximately with the stage 20-stage 19 transition. Figure modified from 

Poore and others (1993). 

counted for selected samples in core 5 that contained 

abundant benthic foraminifers. Benthic census data for the 

remaining samples with abundant foraminifers in core 5 and 

all samples with abundant benthic foraminifers in core 3 

were obtained by tabulating the first 200-300 specimens in 

strewn slides. Tabulation of specimens began with the 

> 150-JLm size fraction and extended to the 63- to 150-JLm 

size fraction only when it was required to obtain >200 

specimens. All benthic foraminifers were picked from the 

>63-JLm fraction of samples, which contained rare benthic 

specimens. After cores 5 and 3 were completed, representative samples from cores 9 and 7 were scanned for 

comparison with the assemblages noted in cores 5 and 3. 

Census data for benthic foraminifers in cores 5 and 3 

are presented in tables 2 and 3, respectively. Work in 

progress on box core top samples from Northwind Ridge 

shows that the> 106-JLm and> 125-JLm benthic foraminifer 

census data provide the same basic oceanographic information as the >63-JLm census data. Thus, we plan to use 

quantitative census of the > 125-JLm size fraction in our 

future studies of foraminifer assemblages from the Arctic 

Ocean. 

The planktic foraminifer abundance data show that 

foraminifers are concentrated in distinctive layers (fig. 5) 

that generally coincide with dark-brown beds. Three intervals of abundant planktic foraminifers occur in unit M (M1, 

M2, and M3) and in unit L (L1, L2, and L3). The interval 

labeled L3 in core 3 contains relatively few foraminifers 

( <500/g) along with common iron manganese grains that 

are molds and internal casts of foraminifers. Thus, L3 in 
Depth 

(em) 

0 

100 

200 

300 

400 

500 

600 

Core 9 

Water depth = 945 m 

Planktic foraminifers >150 ~m L· P?r gra")l 5.000 

M1 

M2 

M3 

L1 

L2 

0 400 

Matuyama-Brunhes 

polarity reversal horizon 

Jaramillo 

normal polarity 

event 

Benthic foraminifers >150 ~m 

per gram 

Core 5 

Waterdepth = 1,089 m 

Planktic foraminifers >150 ~m 

o p~r grar;n 5,000 

~ ... :. M1 

400 

Benthic foram1 n1fers > 150 ~m 

per gram 

L1 

L2 

Depth 

(em) 

0 

J 

Core 3 

Waterdepth = 1,909 m 

Planktic foraminifers >150 ~m 

o per gram 5,000 

M1 

M2 

L2 

400 

Benthic foraminifers > 150 ~~m 

per gram 

Core 7 

Water depth = 3,513 m 

Depth 

(em) 

0 

Planktic foraminifers >150 ~m 

o per gram 5,000 

.... M1?' 

100 

200 

300 

400 

Benthic foraminifers >150 ~m 

per gram 

EXPLANATION 

S Brown beds 

D Benthic foraminifer plot 

D Planktic foraminifer plot 

Figure 5. Foraminifer abundance data for Northwind Ridge cores 9, 5, 3, and 7. Abundance data are from Foley and Poore (1991, 1993). M, L, K, 

J, and I are Arctic lithostratigraphic units of Clark and others (1980) (see text and fig. 2). M1, M2, M3, L1, L2, and L3 designate planktic foraminifer 

abundance peaks within lithostratigraphic units. Matuyama-Brunhes polarity reversal horizon and Jaramillo normal polarity event for core 5 are from 

Poore and others ( 1993). 

a 

~ ~ 

I 

C.ll 

\0 
10 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

core 3 is the residue of a foraminifer abundance peak. Core 

5 shows two foraminifer abundance peaks in unit K. Core 7, 

which was taken from a depth of 3,513 m, contains 

significant numbers of foraminifers in unit M and the top of 

unit L (L 1). Foraminifers from deeper intervals in core 7 are 

rare and, where present, are corroded and pitted. The top of 

core 7 was lost during coring, and the upper foraminifer 

peak represents foraminifers in burrows that extended down 

from the unrecovered surface unit. Burrows with brown 

infilling are evident on the split face of the core. The peaks 

M2, M3, and L1 are well defined. 

The stratigraphic distributions of the planktic foraminifer abundance peaks in units M and L are very similar in 

cores 9, 5, and 3. The poor preservation of L3 in core 3 and 

the absence of L2 and L3 in core 7 represent increased 

dissolution reflecting the deeper location of cores 3 and 7 

(see following discussion). The similarity of the records in 

the shallow cores and the upper part of core 3 support the 

lithostratigraphic correlations and indicate that the foraminifer abundance variations reflect regional oceanographic 

events and are not features caused by localized sedimentary 

processes on Northwind Ridge. 

PALEOCEANOGRAPHY 

GLACIAL-INTERGLACIAL CYCLES 

The environmental significance of foraminifer abundance variations in Arctic cores is controversial (see Herman and others, 1989, for summary). One interpretation 

concludes that foraminifer-rich intervals represent interglacial conditions reflecting seasonally absent or reduced ice 

cover leading to increased productivity; intervals barren or 

nearly barren of foraminifers are considered to represent 

glacial conditions with thicker ice cover and lower productivity (Clark, 1971; Aksu, 1985). An alternative interpretation concludes that foraminifer-poor intervals represent 

climates warmer than today when low-salinity surface 

waters due to increased river runoff or melting ice resulted 

in low productivity of planktic foraminifers (Herman, 

1983). Foraminifer-poor intervals have also been interpreted as dissolution events occurring during interglacial 

and early glacial intervals (Morris and Clark, 1986). Many 

factors, including dissolution, surface-water productivity, 

downslope transport, and dilution by ice-rafted material, 

influence the abundance of foraminifers in Arctic sediments. Interaction of these factors is complex, and no single 

factor can explain all of the variability seen in Arctic 

sediments. We conclude that the foraminifer-rich intervals 

in the Northwind Ridge cores included in this study represent interglacial deposits for the following reasons. 

Sediment-trap studies in the Fram Strait (Hebbeln and 

Wefer, 1991) and the Norwegian-Greenland Sea (William 

Curry, Woods Hole Oceanographic Institution, oral commun., 1993) show that ice cover eliminates or greatly 

curtails biogenic and lithogenic sedimentation and that 

sedimentation resumes as soon as open-water conditions 

return. Productivity is highest near the ice margin. The 

Northwind Ridge area of the western Arctic has 1 to 2m of 

ice cover during most of the year but is near the northern 

margin of waters that are normally ice free for several 

months in the late summer (Untersteiner, 1990). Leads and 

polynyas of open water were observed over Northwind 

Ridge during the 1988 cruise, and brown, plankticforaminifer-rich muddy sands were recovered in the tops of 

most piston and gravity cores from Northwind Ridge. 

Analyses of Neogloboquadrina pachyderma from the surface foraminifer-rich bed in core 5 yielded carbon-14 dates 

of 5,186±91 yr B.P. at 0-2 em depth and 7,800±118 yr 

B.P. at 4.6-5.6 em depth (fig. 4). The age of 5,186 yr B.P. 

for the top interval probably reflects the effects of burrowing and the loss of the uppermost sediment during piston 

coring. A carbon-14 date of 8,480±80 yr B.P. was 

obtained from the 3-cm level of core 9, and a date of 

4,830± 100 yr B.P. was obtained from the 1-cm level of 

core 3. Thus, the brown, planktic-foraminifer-rich surface 

sediments of Northwind Ridge were deposited during the 

current interglacial stage. Seasonally open water results in 

high productivity, abundant planktic foraminifers in the 

water column, and preservation of planktic foraminifers in 

the underlying sediments. By analogy with surface sediments, we infer that the repeated planktic-foraminifer-rich 

beds occurring at depth in N orthwind Ridge cores record 

past interglacial stages. 

The positive correlation of planktic and benthic foraminifer abundances throughout most of the shallow-water 

cores 9 and 5 and in core 3 (fig. 5) indicates that the major 

variations in planktic foraminifer abundances in these cores 

are not caused primarily by variable dissolution of sediment 

with a similar foraminifer content. Neogloboquadrina 

pachyderma is very resistant to dissolution (Berger, 1979; 

Malmgren, 1983), but many benthic foraminifers are even 

more resistant to dissolution (Berger, 1973, 1979). Abundance variations due primarily to differential dissolution of 

sediments having initially similar foraminifer components 

would result in variable ratios of planktic to benthic 

foraminifers and would include associations of common, 

robust benthic foraminifers with low numbers of planktic 

foraminifers. Additionally, no major changes in fragmentation were observed, which would be expected if the 

observed abundance fluctuations in the shallow cores were 

caused primarily by changes in dissolution intensity (Malmgren, 1983). Thus, we interpret the major variations in 

planktic foraminifer abundances in units M through K of 

cores 9, 5, and 3 to be primarily a function of productivity 

related to ice cover rather than a function of changes in 

dissolution. 

The record from core 5 extends through the Brunhes 

into the Matuyama. The number and stratigraphic distribu-
PALEOCEANOGRAPHY 11 

tion of interglacial, planktic-foraminifer-rich horizons in 

core 5 (fig. 4) are similar to the number and stratigraphic 

distribution of oxygen-isotope minima (representing interglacial stages) recorded in the isotope records of the 

Brunhes interval of marine cores at lower latitudes. Most 

lower latitude records indicate that the Matuyama-Brunhes 

polarity reversal horizon is associated with the stage 20-19 

transition and that interglacial stage 21 occurs near the end 

of the Matuyama (Imbrie and others, 1984; Shackleton and 

others, 1990). We infer that the foraminifer abundance peak 

just below 3 . 5 m in core 5 represents stage 21 and the 

foraminifer peak that begins just above the base of the 

Brunhes, around 3.4 m, represents stage 19 (Poore and 

others, 1993). We correlate the top four foraminifer abundance peaks with stages 1, 5, 7, and 9. Matching the 

remaining foraminifer abundance peaks with specific isotope stages is equivocal. Inspection of figure 4 indicates that 

several plausible correlations between the foraminifer peaks 

and interglacial stages are possible. 

Previous records from the central and western Arctic 

indicated that foraminifers are generally abundant throughout most of unit M and in the upper third of unit L (Clark, 

1971; Aksu, 1985; Scott and others, 1989). In contrast, the 

relatively expanded record in our cores demonstrates that 

foraminifers are concentrated in discrete layers that we 

correlate with global interglacial stages. Abundance variations of planktic foraminifers (> 150 J.Lm) in the relatively 

expanded section of T3-67-11 (Darby and others, 1989), 

from the slope of the Mendeleyev Ridge, also indicate that 

foraminifers occur in discrete beds separated by intervals 

that are barren or nearly barren of foraminifers. The 

differences between foraminifer occurrences reported by 

Clark (1971), Aksu (1985), and Scott and others (1989) and 

those found in our study may represent regional variations 

in the response of the Arctic to climate cycles or may be due 

to nonlinear sediment accumulation rates within and 

between cores. It is likely that bioturbation and low accumulation rates have blurred the foraminifer record in many 

central and western Arctic cores. For example, the combined thickness of unit M and unit L in CESAR (Canadian 

Expedition to Study the Alpha Ridge) core 14 from Alpha 

Ridge is about 42 em (Scott and others, 1989), whereas the 

thickness of units MandL in Northwind Ridge core 9 is 626 

em. 

Two foraminifer-rich beds occur in unit K of core 5 

(fig. 4). The section below unit Kin core 5 does not contain 

foraminifer-rich horizons, although the magnetostratigraphy shows that this interval includes the Jaramillo normal 

polarity event and thus spans several hundred thousand 

years, during which several glacial-interglacial cycles 

occurred. Apparently, interglacials are not represented by 

distinctive foraminifer-rich beds below unit K as they are in 

units M through K. However, the sparse planktic and 

calcareous benthic foraminifers at 425 em and 440 em in 

unit I could be dissolved remnants of foraminifer-rich beds 

representing interglacial events. 

The N orthwind Ridge data show that distinct cycles in 

the abundance of foraminifers occur throughout the Brunhes 

Normal Polarity Zone. Our interpretation of the foraminifer 

abundance variations as resulting from glacial-interglacial 

cycles implies that, with the exception of major interglacial 

stages, the Arctic Ocean since stage 21 has been covered by 

thick sea ice, which resulted in low productivity of foraminifers. The N orthwind Ridge Brunhes record of foraminifer 

abundance fluctuations supports previous conclusions that 

unit M represents oxygen-isotope stages 1-8 and that stage 

9 occurs at the top of unit L; these conclusions were based 

on variations in sand-fraction data (Clark and others, 1980) 

and limited oxygen-isotope data from Arctic cores (Aksu, 

1985; Scott and others, 1989). Our results also support the 

conclusions of Boyd and others (1984) that climate variations in the Arctic are in phase with glacial-interglacial 

cycles observed in other proxy records of the Brunhes. The 

Northwind Ridge data are too limited to speculate on 

pre-Brunhes conditions and their relation to events within 

and outside of the Arctic Ocean. 

DEEP WATERS 

Changes in bottom-water conditions and structure 

through the late Pleistocene are indicated by differences in 

preservation of foraminifers and by changes in benthic 

assemblages within and between cores from different 

depths. Although most of the variation in foraminifer 

abundances seen in cores 9, 5, and 3 and the uppermost part 

of core 7 reflects changing productivity, significant dissolution is evident in much of core 7 and in the lower parts of 

cores 5 and 3. Dissolution effects are seen by comparing the 

foraminifer abundances in cores from different water depths 

(fig. 5). Foraminifer peaks M1, M2, M3, and L1 are in all 

four cores. Foraminifer peak L2 is present in cores 9, 5, and 

3. Peak L2 is not recorded in core 7. However, L2 may be 

missing from core 7 because of erosion. L3 is well defined 

in cores 9 and 5 but is represented by a residual assemblage 

in core 3. Some calcareous specimens are present, but most 

of the foraminifers are preserved in core 3 as iron manganese molds and internal casts. No indication of L3 was 

observed in core 7. Thus, during deposition of L3, the 

carbonate compensation depth (CCD) was near but just 

below the depth of core 3. Unit K was identified in cores 5 

and 7. Two large peaks of foraminifer abundance occur in 

unit K of core 5, whereas, in core 7, unit K is essentially 

barren of calcareous foraminifers. Unit I of core 5 contains 

two intervals with low abundances of benthic foraminifers 

(fig. 4) and rare planktic foraminifers that we interpret as 

dissolved assemblages. Unit I of core 3 yielded only a few 

agglutinated specimens. The short interval of unit I identified above an erosional contact in core 7 is barren of 
12 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

foraminifers. The pattern of preservation of foraminifers in 

Northwind Ridge cores documents a general increase in 

depth of the CCD of the Canada Basin with each successive 

(younger) interglacial stage through the late Quaternary. 

The changes in carbonate preservation seen in Northwind 

Ridge cores are in agreement with previous studies that 

show that the CCD in the central Arctic has progressively 

deepened during the Pleistocene (Morris and Clark, 1986). 

Information in tables 2 and 3 and figures 6 and 7 on 

benthic foraminifer assemblages in cores 5 and 3 was 

obtained by quantitative and qualitative methods using 

several size fractions and cannot be used for detailed 

interpretations. However, the data (figs. 6 and 7) reveal 

several broad features that reflect changing deepwater 

characteristics. Assemblages from M1, M2, M3, and L1 of 

cores 5 and 3 are characterized by Oridorsalis and Stetsonia 

horvathi. Stetsonia is a very small form that is not found in 

the > 150-~J.m size fraction, and it is well represented only 

in samples in tables 2 and 3 that were tabulated at >63 ~J.m. 

Inspection of the <150-~J.m fraction, however, shows that 

Stetsonia is abundant in most samples that contain common 

to abundant foraminifers. Our general observation is that, 

where present, Stetsonia horvathi is the dominant taxon in 

the < 150-~J.m size fraction. 

Differences between benthic foraminifer assemblages 

in the upper part of unit L and in unit M of cores 5 and 3 are 

explained by the depth distribution of modem assemblages 

in Holocene Arctic sediments. For example, published 

distributional data (Lagoe, 1977; Scott and Vilks, 1991) and 

our data from Northwind Ridge box cores (Scott Ishman 

and Kevin Foley, unpub. data, 1993) show that Cassidulina 

teretis has its maximum abundance between 1 ,400 m and 

about 600 m depth throughout the entire Arctic and in the 

Norwegian-Greenland Sea (Belanger and Streeter, 1980; 

Mackensen and others, 1985). Cassidulina teretis is a 

common and consistent component of calcareous assemblages in the upper part of unit L and in unit M of core 5 

(1 ,089 m water depth) but occurs sporadically and in much 

lower abundances in equivalent foraminifer-rich levels of 

core 3 (1 ,909 m water depth). Similarly, Fontbotia wuellerstorfi and Eponides tumidulus, which generally are more 

abundant below 1 ,500 m in the modem Arctic, are important components of core 3 assemblages in the upper part of 

unit L and in unit M but are poorly represented in equivalent 

assemblages from core 5. 

Inspection of selected core 9 and core 7 assemblages 

from units L and M shows that core 9 assemblages are 

similar to core 5 assemblages and that core 7 assemblages 

are similar to core 3 assemblages. Core 7 assemblages, 

however, show distinct signs of dissolution below M2; 

fragments are much more common than in the other cores, 

and test surfaces are pitted and etched. Bulimina aculeata 

occurs in M3 in all four cores and in L 1 of cores 9, 5, and 

3 (assemblages found in L 1 of core 7 are sparse and poorly 

preserved). Bulimina aculeata is not reported from Holocene sediments of the Arctic but is common in low-oxygen 

environments and areas of sediments with high organicmatter content in the North Atlantic (Burgess and Schnitker, 

1990). The benthic foraminifer assemblages in the upper 

part of unit L and in unit M suggest that deepwater 

conditions in the area of North wind Ridge were very similar 

to modem conditions during the last few interglacial stages. 

However, lower oxygen conditions prevailed during M3 

and L1 (probably stages 7 and 9), perhaps reflecting 

increased productivity and thus greater supply of organic 

material to the sea floor. 

A distinct change occurs between L 1 and L2. Except 

for one sample in unit K of core 5, Oridorsalis, which is 

significant in assemblages in the upper parts of all cores, is 

absent below L1 (figs. 6 and 7). Cassidulina teretis continues to be common in the assemblages from L2 and L3 of 

core 5; Bolivina arctica is an important component of some 

assemblages. Core 3 assemblages from the lower part of 

unit L are slightly different from the core 5 assemblages. In 

core 3, the L2 assemblages contain abundant Bolivina 

arctica and Stetsonia with Fontbotia wuellerstorfi as an 

important accessory. L3 is represented by two samples in 

core 3 (table 3, 396.5 and 401.7 em). The upper sample 

(fig. 7) has abundant Stetsonia and Epistominella exigua, 

whereas the lower sample yields a sparse assemblage 

dominated by Bolivina arctic a. Thus, Bolivina arctica 

appears to have taken the place of Oridorsalis in L2 and L3 

assemblages. Epistominella exigua, which is abundant 

between 2,000 and 3,000 m depth in modem benthic 

assemblages in the Norwegian-Greenland Sea (Belanger 

and Streeter, 1980; Mackensen and others, 1985), is essentially absent from L3 assemblages of core 5 (one specimen 

occurs at the top of L3 in the sample from 226.4 em). The 

absence of Epistominella exigua from core 5, coupled with 

the abundance of Epistominella exigua in core 3, may 

reflect the presence of a water-mass boundary between 

cores 3 and 5 during L3 . 

Cassidulina teretis and Bolivina arctica are consistent 

components of benthic assemblages in unit K of core 5 (fig. 

6). Fontbotia wuellerstorfi occurs sporadically along with 

Pullenia bulloides. Cassidulina reniforme, which occurs in 

a few samples from unit L, is a common element in the 

assemblages from the lower part of unit K. A few specimens of Oridorsalis occur in one sample near the base of 

unit K. 

The assemblages recovered from units J and I in core 

5 generally contain Cassidulina reniforme, Cassidulina 

teretis, and Bolivina arctic a (fig. 6). Pullenia bulloides 

dominates one sample (table 2, 439.6 em), and the agglutinated foraminifer Haplaphragmoides obscurus is abundant in several samples from unit I (fig. 6). 

Studies of core tops from the Norwegian-Greenland 

Sea (Macken sen and others, 1985) indicate that Cassidulina 

reniforme is abundant in assemblages from water depths 

between 500 and 1 ,000 m, which is above and partially 
E 

~ 

Q) 

0 

() 

c 

..c 

E. 

Q) 

0 

Stetsonia 

horvathi 

Oridorsalis 

spp. 

Eponides 

tumidulus 

Fontbotia Cassidulina 

wuellerstorfi teretis 

Core 5 

Bulimina 

aculeata 

Bolivina 

arctic a 

Epistominella Cassidulina Haplaphragmoides 

exigua reniforme obscurus 

0 ------. ------. --r------, -;-------, ---=-----. --r------. --r------. ~-----, --r------, --r------. 

50 

J 

1-L. 1--l 1--l 1--l I-t 1-

100 I-t::. 1--t:::=""" I-I 1-{ I-I 1-

150 I-I I-I I-I I-I I-I I-I 1-

200 I-I I-I I-I I-I I-I I-I I-I I-I 1-

250! I-I I-I 1--l 1--l 1--l 1--l 1--l 1--l 1-

300 -I I-I I-I It It- I~ 11. I~ 11 1--.. 

350t I~ 

:1- 1-L 1--l 1--L__ 1--l I -L..- 1-

4001 IJ 1--l I-f 1--l 1--l 1--l 1--l 1-

I 1 I 1 I 1 ll- I 1 II I 1 I 

450--1- I-I I-I I-I I-t I-I 1--1-- I-I 1-t- :l500 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 11 11 11 11 I I I I I I I I I I I I I I I I I I I I I' I I' I' I' 1 1 I oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo 

N'd"<DOOO N'd"<OOOO N'd"<OOOO N-.:t<OOOO N-.:t<OOOO N-.:t<OOOO N-.:t<OOOO N-.:t<OOOO N'd"<OOOO N-.:t<OOOO 

Abundance, in percent 

Standard Arctic 

lithostratigraphic units and 

planktic foraminifer peaks 

JM1 

M ~M2 

~M3 

t------1- L 1 

L I L2 

~ L3 

~ 

K 

1-

J 

~ 

Figure 6. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5. Abundances are plotted for samples yielding 30 or more specimens. 

Lithostratigraphy and location of planktic foraminifer peaks from figure 5. See text for explanation of methods for obtaining benthic foraminifer abundance estimates. 

~ 

('") 

~ tT:1 

> z 

0 

a 

:;o 

> 

~ ~ 

.......... 

w 
E 

..s 

Q.) 

Stetsonia 

horvathi 

0---r------, 

100 

200 

Oridorsalis 

spp. 

Eponides 

tumidulus 

r 

-

Fontbotia 

wuellerstorfi 

~ 

-

.. 

-

1-

-

-

Core 3 

Bulimina 

aculeata 

-

-

Bolivina 

arctic a 

Epistominella Cribroelphidium 

exigua excavatum 

- -

- -

8 300 - - - - - -

c 

..c 

+-' 

Q. 

Q.) 

0 

..... 

~ e: 1-

- r---

_......_ 400 - - ~ 

500 - - - - - -

600 I I I I I I I I I I I I' I' I' I I' I' I' I I' I' I 'I I' I' I' I I' I' I' I 1'1'1'1 000000 000000 000000 000000 000000 000000 000000 000000 N~IDOOO N~IDOOO N~IDOOO N~IDOOO N~IDOOO N~IDOOO N~IDOOO N~IDOOO 

Abundance, in percent 

Standard Arctic 

lithostratigraphic units and 

planktic foraminifer peaks 

I fiM1i 

M2 

M 

~M3 

r-----) L 1 

L ~ L2 

r--

J r---

til L3 

Figure 7. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3. Abundances are plotted for samples yielding 

30 or more specimens. Lithostratigraphy and location of planktic foraminifer peaks from figure 5. See text for explanation of methods for obtaining benthic 

foraminifer abundance estimates. 

-

~ 

i 

> 

~ Cl'.l 

~ ~ 

I 

~ 

~ '"C 

(") 

~ 

~~ 

~ (") 

> z 

> 

~ to 

> Cl'.l 

~ 

Cl'.l 

~ 

~ > 

~ 0 

(") 

~ 
CONCLUSIONS 15 

overlapping the zone of maximum abundance of Cassidulina teretis. However, the factors controlling the distribution of these taxa are unclear. The increase in abundance of 

agglutinated foraminifers in unit I of core 5 and the sparse 

agglutinated foraminifer assemblages found in unit I of core 

3 represent increased dissolution in both cores. 

Clark and others (1990) documented benthic assemblages from unit G in several Arctic cores. They concluded 

that increased exchange between the Arctic and the 

Norwegian-Greenland Sea through the Pram Strait occurred 

at the beginning of deposition of unit G and that the 

increased exchange caused lowering of the Arctic CCD and 

introduction of several North Atlantic taxa such as Fontbotia wuellerstorfi (as Planulina wuellerstorfi) and Oridorsalis (sparse and sporadic as Eponides tener) into the 

Arctic. Clark and others (1990) suggested that there is a 

general trend toward increasing diversity of Arctic benthic 

foraminifer assemblages through the Pleistocene and that 

variations in assemblages are common but that the controls 

and significance of the changes are unknown. 

Scott and others (1989) conducted a detailed study of 

Quaternary benthic foraminifers in three CESAR cores 

recovered from a relatively narrow depth range of 1,370 to 

1,555 m on Alpha Ridge of the central Arctic Ocean (fig. 

1B). Benthic assemblages in these CESAR cores, of which 

one, core 14, extends through the entire Pleistocene, show 

changes that were interpreted to represent increased 

exchange between the Atlantic and the NorwegianGreenland Sea. Scott and others ( 1989) found that the first 

significant (> 1 percent) occurrences of North Atlantic 

benthic species in CESAR cores are within unit M and that 

the first North Atlantic taxon to appear is Oridorsalis 

umbonatus in the lower part of unit M, followed sequentially by Eponides tumidulus and Planulina wuellerstorfi 

(=Fontbotia wuellerstorfi in this study). Scott and others 

( 1989) inferred that the changes they observed in CESAR 

benthic assemblages must have predated any similar 

changes in the western Arctic. 

Aside from the sparse occurrence in unit K of core 5, 

the Northwind Ridge benthic data also show a dramatic first 

appearance of Oridorsalis, but the first appearance is in the 

upper part of unit L. In addition, Fontbotia wuellerstorfi 

forms a significant percentage of assemblages in units L 

(cores 5 and 3) and K (core 5) (see tables 2 and 3). The 

Alpha Ridge benthic data were tabulated from the >63-I.Lm 

size fraction, whereas our data are a mixture of quantitative 

and qualitative data, some of which were based on the 

> 150-J.Lm size fraction. However, the basic differences 

between the sequence of events at Northwind Ridge and that 

at Alpha Ridge cannot be explained by differences in 

methodology. The first appearance of Oridorsalis at Northwind Ridge is very evident in all size fractions, and several 

of the significant occurrences of Fontbotia wuellerstorfi in 

unit K of Northwind Ridge core 5 are based on the total 

assemblage >63 J.Lm and quantitative splits of the >63-J.Lm 

size fraction. Similarly, placing the base of unit M lower in 

our cores (below the pinkish-white bed designated NPWB 

in figure 2) would not alter the fact that, in contrast to the 

CESAR core 14 record, significant occurrences of Fontbotia wuellerstorfi occur stratigraphically below the first 

significant occurrence of Oridorsalis. In addition, Clark 

and others (1990) reported significant occurrences of Fontbotia wuellerstorfi in assemblages from unit G. 

Our data on benthic assemblages from Northwind 

Ridge indicate that the history of deepwater evolution in the 

western Arctic and its communication with the eastern 

Arctic and the world's oceans is complex. Substantial 

changes occur in both the abundance and composition of 

late Quaternary benthic assemblages from Northwind Ridge 

both within cores and between equivalent horizons in cores 

from different depths. The changes seen at N orthwind 

Ridge by us and at Alpha Ridge by Scott and others (1989) 

cannot be completely explained by simple changes in 

connections of the Arctic Ocean with the North Atlantic 

through the Norwegian-Greenland Sea. Studies of core tops 

from the Arctic and the Norwegian-Greenland Sea show 

that Oridorsalis is more abundant in deeper waters than 

Fontbotia wuellerstorfi, but they have very similar upper 

depth limits. In addition, Epistominella exigua, which is 

strongly associated with Fontbotia wuellerstorfi in modem 

samples from the Norwegian-Greenland Sea (Mackensen 

and others, 1985), is absent from Holocene and unit M 

sediments from the central and western Arctic (Lagoe, 

1977; Scott and others, 1989; this study). 

Additional sampling and study of Pliocene and Pleistocene sections from Northwind Ridge and other Arctic 

areas that include careful documentation of benthic assemblages along depth transects are required to develop a better 

understanding of the four-dimensional history of the Arctic 

Ocean and its influence on global oceanic circulation. 

CONCLUSIONS 

1. Lithostratigraphic units established for the upper Quaternary of the central and western Arctic Ocean (Clark 

and others, 1980) are recognized in sediment cores from 

Northwind Ridge. Howe~er, the Northwind Ridge section is expanded and contains one or more coarse, 

clast-rich units that are not present in the central Arctic 

sequence. 

2. Foraminifers are concentrated in discrete intervals 

within the Brunhes Normal Polarity Zone. Available age 

control and stratigraphic distribution of the foraminiferrich beds indicate that they represent interglacial conditions. 

3. Differential preservation of foraminifers within and 

between cores from different water depths indicates that 

the CCD became progressively deeper during successive 

(younger) interglacial stages of the last million years. 
16 QUATERNARY STRATIGRAPHY AND PALEOCEANOGRAPHY, CANADA BASIN, WESTERN ARCTIC OCEAN 

4. Changes in benthic foraminifer assemblages within and 

between cores of the Northwind Ridge depth transect 

indicate that the character and structure of deep waters in 

the western Arctic evolved substantially during the late 

Quaternary. The most striking change occurs at an 

interglacial stage we correlate with oxygen-isotope stage 

9. At this change, Oridorsalis becomes a dominant 

component of benthic assemblages that were deposited 

between 3,513 and 945 m depth. 

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Aksu, A.E., 1985, Planktonic foraminiferal and oxygen isotopic 

stratigraphy of CESAR cores 102 and 103: Preliminary 

results, in Jackson, H.R., Mudie, P.J., and Blasco, S.M., 

eds., Initial geological report on CESAR-The Canadian 

Expedition to Study the Alpha Ridge, Arctic Ocean: Canada 

Geological Survey Paper 84--22, p. 115-124. 

Belanger, P.E., and Streeter, S.S., 1980, Distribution and ecology 

of benthic Foraminifera in the Norwegian-Greenland Sea: 

Marine Micropaleontology, v. 5, no. 4, p. 401--428. 

Berger, W .H., 1973, Deep-sea carbonates; Pleistocene dissolution 

cycles: Journal of Foraminiferal Research, v. 3, no. 4, p. 

187-195. 

---1979, Preservation of Foraminifera: Society of Economic 

Paleontologists and Mineralogists Short Course [Notes] No. 

6, p. 105-155. 

Boyd, R.F., Clark, D.L., Jones, Glenn, Ruddiman, W.F., Mcintyre, A., and Pisias, N.G., 1984, Central Arctic Ocean 

response to Pleistocene Earth-orbital variations: Quaternary 

Research, v. 22, no. 1, p. 121-128. 

Burgess, M.V., and Schnitker, Detmar, 1990, Morphometry of 

Bulimina aculeata Orbigny and Bulimina marginata Orbigny: 

Journal of Foraminiferal Research, v. 20, no. 1, p. 37--49. 

Campbell, J.S., and Clark, D.L., 1977, Pleistocene turbidites of 

the Canada Abyssal Plain of the Arctic Ocean: Journal of 

Sedimentary Petrology, v. 47, no. 2, p. 657-fJ70. 

Clark, D .L., 1971, Arctic Ocean ice cover and its late Cenozoic 

history: Geological Society of America Bulletin, v. 82, no. 

12, p. 3313-3324. 

Clark, D.L., Chern, L.A., Hogler, J.A., Mennicke, C.M., and 

Atkins, E.D., 1990, Late Neogene climate evolution of the 

central Arctic Ocean: Marine Geology, v. 93, p. 69-94. 

Clark, D.L., Whitman, R.R., Morgan, K.A., and Mackey, S.D., 

1980, Stratigraphy and glacial-marine sediments of the 

Amerasian Basin, central Arctic Ocean: Geological Society 

of America Special Paper 181, 57 p. 

Darby, D.A., Naidu, A.S., Mowatt, T.C., and Jones, G., 1989, 

Sediment composition and sedimentary processes in the 

Arctic Ocean, in Herman, Yvonne, ed., The Arctic seas: 

New York, Von Nostrand Reinhold, p. 657-720. 

Foley, K.M., and Poore, R.Z., 1991, Planktic foraminifer census 

data from Northwind Ridge core 5, Arctic Ocean: U.S. 

Geological Survey Open-File Report 91-346, 6 p. 

---1993, Planktic foraminifer census data from Northwind 

Ridge cores PI-88-AR P3, PI-88-AR P7 and PI-88-AR P9, 

Arctic Ocean: U.S. Geological Survey Open-File Report 

93-218, 11 p. 

Goldstein, R.H., 1983, Stratigraphy and sedimentology of icerafted and turbidite sediment, Canada Basin, Arctic Ocean, in 

Molnia, B.F., ed., Glacial-marine sedimentation: New York, 

Plenum Press, p. 367--400. 

Hebbeln, Dierk, and Wefer, Gerold, 1991, Effects of ice coverage 

and ice-rafted material on sedimentation in the Fram Strait: 

Nature (London), v. 350, no. 6317, p. 409--411. 

Herman, Yvonne, 1983, Baffin Bay; Present-day analog of the 

central Arctic during late Pliocene to mid-Pleistocene time: 

Geology, v. 11, no. 6, p. 356--359. 

Herman, Yvonne, Osmond, J.K., and Somayajulu, B.L.K., 1989, 

Late Neogene Arctic paleoceanography; Micropaleontology, 

stable isotopes, and chronology, in Herman, Yvonne, ed., 

The Arctic seas: New York, Van Nostrand Reinhold, p. 

581-fJ55. 

Hunkins, Kenneth, and Kutschale, Henry, 1967, Quaternary 

sedimentation in the Arctic Ocean, in Progress in oceanography, v. 4, The Quaternary history of the ocean basins: New 

York, Pergamon Press, p. 89-93. 

Imbrie, John, Hays, J.D., Martinson, D.G., Mcintyre, A., Mix, 

A.C., Morley, J.J., Pisias, N.G., Prell, W.L., and Shackleton, N.J., 1984, The orbital theory of Pleistocene climate: 

Support from a revised chronology of the marine <1 180 record, 

in Berger, A., ed., Milankovitch and climate-Understanding the response to astronomical forcing: Boston, D. Reidel, 

p. 269-305. 

Kellogg, T. B. , 1977, Paleoclimatology and paleo-oceanography 

of the Norwegian and Greenland Seas; The last 450,000 

years: Marine Micropaleontology, v. 2, no. 3, p. 235-249. 

Kipp, N.G., 1976, New transfer function for estimating past seasurface conditions from sea-bed distribution of planktonic 

foraminiferal assemblages in the North Atlantic, in Cline, 

R.M., and Hays, J.D., eds., Investigation of late Quaternary 

paleoceanography and paleoclimatology: Geological Society 

of America Memoir 145, p. 3--41. 

Lagoe, M.B., 1977, Recent benthic Foraminifera from the central 

Arctic Ocean: Journal of Foraminiferal Research, v. 7, p. 

106--129. 

Mackensen, A., Sejrup, H.P., and Jansen, E., 1985, The distribution of living benthic Foraminifera on the continental slope 

and rise off southwest Norway: Marine Micropaleontology, 

v. 9, no. 4, p. 275-306. 

Malmgren, B.A., 1983, Ranking of dissolution susceptibility of 

planktonic Foraminifera at high latitudes of South Atlantic 

Ocean: Marine Micropaleontology, v. 8, no. 3, p. 183-191. 

Minicucci, D.A., and Clark, D.L., 1983, A late Cenozoic 

stratigraphy for glacial-marine sediments of the eastern Alpha 

Cordillera, central Arctic Ocean, in Molnia, B.F., ed., 

Glacial-marine sedimentation: New York, Plenum Press, p. 

331-365. 

Morris, T .H., and Clark, D.L., 1986, Pleistocene calcite lysocline 

and paleocurrents of the central Arctic Ocean and their 

paleoclimatic significance: Paleoceanography, v. 1, no. 2, p. 

181-195. 

Phillips, R.L., Grantz, Arthur, Mullen, M.W., Rieckl H.J., 

McLaughlin, M.W., and Selkirk, T.L., 1992, Summary of 

lithostratigraphy and stratigraphic correlations in piston cores 

from Northwind Ridge, Arctic Ocean, from USCGC Polar 

Star, 1988: U.S. Geological Survey Open-File Report 

92--426, 110 p. 
REFERENCES CITED 17 

Poore, R.Z., Phillips, R.L., and Rieck, H.J., 1993, Paleoclimate 

record for Northwind Ridge, western Arctic Ocean: Paleoceanography, v. 8, p. 149-159. 

Scott, D.B., Mudie, P.J., Baki, V., MacKinnon, K.D., and Cole, 

F.E., 1989, Biostratigraphy and late Cenozoic paleoceanography of the Arctic Ocean; Foraminiferal, lithostratigraphic, 

and isotopic evidence: Geological Society of America Bulletin, v. 101, no. 2, p. 260-277. 

Scott, D.B., and Vilks, Gustav, 1991, Benthic Foraminifera in the 

surface sediments of the deep-sea Arctic Ocean: Journal of 

Foraminiferal Research, v. 21, no. 1, p. 20-38. 

Shackleton, N.J., Berger, A., and Peltier, W.R., 1990, An 

alternative astronomical calibration of the lower Pleistocene 

timescale based on ODP Site 677, in The late Cenozoic ice 

age, Transactions of the Royal Society of Edinburgh: Earth 

Sciences, v. 81, no. 4, p. 251-261. 

Untersteiner, Norbert, 1990, Structure and dynamics of the Arctic 

Ocean ice cover, in Grantz, Arthur, Johnson, L., and 

Sweeney, J.F., eds., The Arctic Ocean region, v. L ofThe 

geology of North America: Boulder, Colo., Geological Society of America, p. 37-51. 

Tables 2-3 begin on p. 18 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5. 

[Total number of specimens in each sample is in the bottom row. Taxa that occurred in low abundances in only one or two samples are not included. Percentages may not add to 100 because of rounding 

or because of elimination of rare taxa. See text for identification of lithostratigraphic units 1-M (Clark and others, 1980). Planktic foraminifer abundance peaks M1, M2, M3, L1, L2, and L3 are shown 

in figures 6 and 7. Abundance data for common benthic taxa from samples yielding 30 or more specimens are plotted in figure 6] 

Lithostratigraphic unit 

Planktic foraminifer peak I Ml I 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainjorthia concava .................. . 

Stetsonia horvathi .................... . 

Triloculina frigida .................... . 

Valvulineria arctica. . . . . . . . . . . . . . . . . . . . 

Total number of specimens ............. . 

0 

0 

0 

0 

0 

0 

40 

0 

0 

0 

2 

0 

0 

56 

0 

0 

0 

0 

1 

0 

330 

3 

0 

0 

0 

0 

0 

47 

0 

0 

0 

2 

0 

0 

49 

0 

0 

0 

0 

1 

0 

386 

6 

0 

0 

0 

2 

0 

58 

0 

0 

0 

0 

0 

0 

39 

0 

0 

0 

0 

0 

0 

425 

9 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

12 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

13 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

17.1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

UnitM 

21 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

26 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

29.2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

32 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

35 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

25 

0 

75 

0 

0 

0 

0 

36 

39 

0 

1 

0 

0 

4 

0 

0 

0 

0 

0 

7 

0 

0 

81 

3 

0 

690 

M2 

40 

0 

0 

0 

0 

0 

20 

0 

0 

0 

0 

0 

41 

0 

2 

0 

28 

6 

0 

527 

44 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

10 

-

00 

0 

e 

I 

--<: 

en 

~ 

~ ::c: 

--<: 

~ t:l 

~ g 

~ 

~ ~ 

~-< 

n 

~ ~ tJj 

> en 

~ 

~ tr1 

en 

~ 

~ 

n 

~ 0 

n 

~ 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua . ................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Triloculina frigida . ................... . 

Valvulineria arctica. . . . . . . . . . . . . . . . . . . . 

Total number of specimens ............. . 

47.6 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

54 

0 

0 

0 

0 

15 

0 

13 

M2 

50.8 

0 

0 

7 

0 

0 

14 

0 

0 

0 

0 

1 

18 

0 

8 

23 

4 

17 

413 

54.5 

0 

0 

0 

33 

0 

0 

0 

0 

0 

0 

0 

0 

33 

0 

0 

0 

0 

0 

11 

9 

59 

0 

0 

0 

5 

0 

40 

0 

0 

0 

0 

0 

50 

0 

0 

0 

0 

2 

99 

65 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

69 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

73 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

UnitM 

75.4 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

32 

78 

0 

1 

0 

0 

0 

33 

0 

0 

0 

0 

0 

0 

64 

0 

0 

0 

I 

0 

0 

467 

79 

0 

1 

0 

0 

0 

32 

0 

0 

0 

0 

0 

0 

66 

0 

0 

0 

0 

0 

0 

333 

81 

0 

5 

0 

0 

0 

14 

0 

0 

0 

5 

0 

0 

59 

0 

0 

0 

0 

0 

0 

44 

82 

0 

6 

0 

0 

2 

30 

0 

0 

0 

0 

0 

0 

46 

0 

0 

3 

6 

4 

174 

87 

0 

56 

0 

0 

0 

11 

0 

0 

0 

6 

0 

0 

22 

0 

0 

0 

0 

0 

0 

18 

M3 

89 

0 

50 

0 

0 

0 

23 

0 

0 

0 

2 

0 

0 

17 

0 

0 

0 

0 

5 

0 

454 

94.4 

0 

50 

0 

0 

0 

21 

0 

6 

0 

0 

0 

0 

24 

0 

0 

0 

0 

0 

0 

34 

t""" 

~ tTl 

en 

N 

I 

w 

-\0 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme . ................ . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Triloculina frigida .................... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

M3 

98 

0 

31 

0 

0 

0 

15 

0 

0 

0 

0 

0 

0 

38 

0 

0 

0 

0 

15 

0 

26 

101 

0 

42 

0 

0 

0 

25 

0 

0 

0 

0 

0 

0 

27 

0 

2 

0 

0 

2 

0 

48 

103 

1 

19 

1 

0 

0 

49 

0 

3 

13 

0 

0 

0 

2 

0 

0 

2 

5 

4 

0 

670 

104 

0 

13 

0 

0 

0 

69 

0 

0 

0 

0 

0 

0 

18 

0 

0 

0 

0 

0 

0 

78 

UnitM 

107 110 

0 

3 

0 

0 

0 

88 

0 

0 

0 

0 

0 

0 

3 

0 

2 

0 

0 

0 

0 

64 

0 

15 

0 

0 

0 

74 

0 

0 

0 

0 

0 

0 

2 

0 

0 

0 

0 

0 

0 

62 

113.4 

0 

57 

0 

0 

0 

31 

0 

0 

0 

0 

0 

0 

11 

0 

0 

0 

0 

0 

0 

87 

118 

0 

50 

0 

0 

0 

50 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

120 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

121.4 

0 

48 

0 

0 

0 

9 

0 

0 

0 

0 

0 

0 

43 

0 

0 

0 

0 

0 

0 

23 

Unit L 

[ Ll I 

124 

2 

13 

1 

0 

54 

0 

0 

0 

0 

0 

0 

22 

0 

0 

1 

3 

3 

1265 

127.2 

0 

33 

0 

0 

0 

53 

0 

0 

0 

0 

0 

0 

13 

0 

0 

0 

0 

0 

0 

15 

130.2 

0 

50 

0 

0 

0 

30 

0 

0 

0 

10 

0 

0 

10 

0 

0 

0 

0 

0 

0 

10 

136 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

140 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

~ 

I 

~ en 

~ 

~ >-<: 

~ ti 

0 

~ (') 

~ 

~ a! 

~ 

(') 

~ ;l> 

t;:xj 

;l> 

en 

~ 

en 

~ 

~ 

~ 

~ 

~ 

~ 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Triloculina frigida .................... . 

Valvulineria arctica. . . . . . . . . . . . . . . . . . . . 

Total number of specimens ............. . 

141.2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

146 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

151 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

155.3 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

160 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

161 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

163.2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Unit L 

167 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

171 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

174.4 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

177 

0 

0 

0 

0 

0 

67 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

179 

17 

0 

3 

0 

0 

52 

0 

2 

0 

3 

2 

0 

0 

0 

0 

9 

6 

I 

3 

540 

L2 

183 

0 

0 

0 

0 

0 

57 

14 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

185 

0 

0 

0 

0 

0 

67 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

187.5 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

..., 

> t:::C 

~ CZl 

lf 

\.).) 

N 

...... 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica . . . . . . . . . . . . . . . . . . . . . . . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplophragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi . . . . . . . . . . . . . . . . . . . . . 

Triloculina frigida .................... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

190 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

L2 

192 

0 

0 

0 

0 

0 

80 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

5 

195.5 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

14 

201.5 

0 

0 

0 

0 

0 

33 

67 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

205 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

208.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

211 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Unit L 

217 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

221 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

I L3 I 

226.4 

0 

0 

0 

0 

0 

0 

33 

33 

0 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

230 

0 

0 

4 

0 

1 

77 

0 

0 

0 

0 

0 

3 

0 

0 

0 

10 

0 

2 

1954 

232.5 

0 

0 

0 

0 

0 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

236 

15 

0 

2 

0 

2 

63 

0 

0 

0 

0 

0 

2 

0 

0 

0 

15 

0 

0 

1521 

239 

0 

0 

0 

0 

0 

82 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

11 

244 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

N 

N 

i 

~ (I) 

~ ~ '"C 

~ 

~ 

~ 

§ 

() 

I 

() 

> z 

> 

§Z 

ttl 

> (I) 

~z 

(I) 

~ 

~ ~ () 

~ 

g 

~ 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi . . . . . . . . . . . . . . . . . . . . . 

Triloculina frigida .................... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

247 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

·247.3 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

251 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

253 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

255 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

257 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

262 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Unit L 

267 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

270 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

274 

0 

0 

0 

0 

0 

50 

50 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

279 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

283 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

286 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

287 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

290 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

~ ~ en 

~ 

N 

w 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5 -Continued. N 

+::-. 

Lithostratigraphic unit Unit L I UnitK 10 

c 

~ Planktic foraminifer peak tr1 

~ Sample depth (em) 292 297 302 304 308 311 317 327 332 335 339 341.6 348.8 352 356 > ::0 

~ 

Bolivina arctica . . . . . . . . . . ............. 0 0 0 0 0 15 6 0 0 0 13 2 8 34 32 en 

Bulimina 

Buliminella 

aculeata 

elegantissima 

..................... 

............... 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 0 

1 0 

0 ~ ~ 

Cassidulina laevigata .................. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Cassidulina reniforme .................. 0 0 0 0 0 1 0 0 0 0 5 26 17 27 32 ~ 

Cassidulina teretis. . . . . . . . . . . . . . ....... 0 0 0 0 0 52 58 86 100 100 64 56 0 12 21 ~ ~ Cribroelphidium excavatum ............. 0 0 0 0 0 1 0 0 0 0 0 0 17 2 0 > Epistominella exigua ................... 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 z 

Eponides tumidulus .................... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 

Fontbotia wuellerstorfi ................. 0 0 0 0 0 5 22 0 0 0 0 0 0 1 0 ~ Globocassidulina subglobosa ............ 0 0 0 0 0 0 0 0 0 0 0 0 17 0 0 tr1 

0 

Haplophragmoides obscurus . ............ 0 0 0 0 0 8 0 14 0 0 0 0 0 1 0 (j 

Oridorsalis spp ........................ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ~ Pullenia bulloides ..................... 0 0 0 0 0 0 3 0 0 0 0 0 8 3 0 z 

0 

Quinqueloculina arctica ................ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

~ Stainforthia concava ................... 0 0 0 0 0 2 2 0 0 0 1 0 8 2 5 

Stetsonia horvathi . . . . . . . . . . . .......... 0 0 0 0 ~ 0 2 0 0 0 0 12 0 0 4 2 ~~ Triloculina frigida ..................... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (j 

Valvulineria arctica . ................... 0 0 0 0 0 12 8 0 0 0 0 0 0 9 5 

Total number of specimens .............. 0 0 0 0 0 297 154 7 2 5 1053 57 12 394 2649 ~ > 

IJ:I 

> en 

~z 

en 

~ 

;i 

~ 

!:; 

(j 

~ 

(j 

-

0 

(j 

~ 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5 -Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima . ............. . 

Cassidulina laevigata ................. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Haplophragmoides obscurus . ........... . 

Oridorsalis spp. . . . . . . . . . . . . . . . . . . . . .. . 

Pullenia bulloides .................... . 

Quinqueloculina arctica ............... . 

Stainforthia concava .................. . 

Stetsonia horvathi . . . . . . . . . . . . . . . . . . . . . 

Triloculina frigida . ................... . 

Valvulineria arctica. . . . . . . . . . . . . . . . . . . . 

Total number of specimens ............. . 

Unit K I Unit J --- -

364 

0 

0 

0 

0 

5 

14 

0 

0 

0 

14 

4 

4 

32 

0 

0 

3 

0 

3 

73 

372 

17 

0 

2 

0 

45 

1 

0 

0 

25 

0 

0 

0 

0 

0 

0 

4 

0 

1027 

375.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

383 

0 

0 

0 

0 

61 

17 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

23 

389 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

392 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

395 

5 

0 

0 

0 

67 

7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

8 

5 

0 

112 

399 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

403.2 

0 

0 

0 

0 

33 

0 

33 

0 

0 

0 

33 

0 

0 

0 

0 

0 

0 

0 

0 

3 

404 

4 

0 

0 

0 

82 

2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

4 

0 

3 

295 

414 

23 

0 

0 

0 

50 

0 

0 

0 

0 

0 

1 

0 

0 

0 

12 

0 

10 

871 

Unit I 

415.4 420 

0 

0 

0 

0 

73 

0 

0 

0 

0 

0 

0 

18 

0 

0 

0 

0 

0 

0 

9 

11 

25 

0 

0 

0 

59 

4 

0 

0 

0 

0 

0 

3 

0 

0 

0 

1 

6 

0 

515 

424 

1 

0 

0 

0 

83 

14 

0 

1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

77 

428.8 

0 

0 

0 

0 

0 

67 

0 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

3 

s 

~ Cl.l 

~ 

N 

Vl 
Table 2. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 5 -Continued. 

Lithostratigraphic unit Unit I 

Planktic foraminifer peak 

Sample depth (em) 434 439.6 447 449.8 460 465.7 

Bolivina arctica ....................... 14 0 45 0 0 0 

Bulimina aculeata ..................... 0 0 0 0 0 0 

Buliminella elegantissima ............... 1 0 0 0 0 0 

Cassidulina laevigata .................. 0 0 0 0 0 0 

Cassidulina reniforme .................. 25 17 16 100 1 25 

Cassidulina teretis . .................... 6 0 3 0 2 25 

Cribroelphidium excavatum ............. 4 0 0 0 7 25 

Epistominella exigua ................... 0 0 0 0 0 0 

Eponides tumidulus .................... 0 0 0 0 0 0 

Fontbotia wuellerstorfi ................. 2 3 0 0 0 0 

Globocassidulina subglobosa ............ 0 0 0 0 0 0 

Haplaphragmoides obscurus . ............ 34 0 20 0 67 0 

Oridorsalis spp ........................ 0 0 0 0 0 0 

Pullenia bulloides ..................... 4 81 2 0 1 0 

Quinqueloculina arctica ................ 0 0 0 0 0 0 

Stainforthia concava ................... 5 0 2 0 1 0 

Stetsonia horvathi ............... , ..... 1 0 6 0 0 0 

Triloculina frigida ..................... 0 0 0 0 0 0 

Valvulineria arctic a. . . . . . . . . . . . . . . ..... 0 0 0 0 1 0 

Total number of specimens .............. 473 36 438 1 111 4 

N 

CJ\ 

~ ~ 

~ ~ 

C/) 

~ ~ > 

~ ~ 

~ 0 

(j 

~ tr1 

I 

~~ 

(j 

~ ~ ttl 

> C/) 

;Z 

C/) 

~ 

~ ~ () 

~ 

g 

~ 
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3. 

[Total number of specimens in each sample is in the bottom row. Taxa that occurred in low abundances in only one or two samples are not included. Percentages may not add to 100 because of rounding 

or because of elimination of rare taxa. See text for identification of lithostratigraphic units 1-M (Clark and others, 1980). Planktic foraminifer abundance peaks Mt, M2, M3, Ll, L2, and L3 are shown 

in figures 6 and 7. Abundance data for common benthic taxa from samples yielding 30 or more specimens are plotted in figure 7] 

Lithostratigraphic unit I Unit M 

Planktic foraminifer peak I Ml I 

Sample depth (em) 

Bolivina arctica .... 0 •••• 0 0 0 0 0 • 0 ••••• 0 0 

Buccella frigida .. o •• 0 0 0 •••••• 0 0 • 0 0 0 •• o 

Bulimina aculeata 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 

Buliminella elegantissima 0 • 0 0 o o 0 0 0 0 0 0 •• o 

Cassidulina reniforme 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Cassidulina teretis 0 0 0 0 • 0 0 0 0 0 • 0 0 0 0 •• o 0 0 0 

Cribroelphidium excavatum 0 0 0 0 0 0 0 0 0 0 0 0 0 

Cribrostomoides spo 0 0 0 0 0. 0 0 0 0 0 0 0 0 0 0 0 0 0 

Cyclammina spo 0. 0 0 0 0 0 0 0 0 0 0 0. 0 0 0 0 0 0 0 0 0 

Epistominella exigua 0 0 0 0 0 0 •• 0 0 0 0 0 0 0 0 • 0 0 

Eponides tumidulus 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Fontbotia wuellerstorfi 0 0 0 0 0 0 0 0 0 0 0 o o 0 0 0 0 

Globocassidulina subglobosa 0 0 0 0 0 0 0 0 0 0 0 0 

Glomospira gordialis 0 0 0 0 0 0 0 0 0 0 0 0 o o 0 0 0 0 

Haplaphragmoides obscurus 0 0 0 0 0 0 0 0 0 0 0 0 0 

Oridorsalis sppo 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Quinqueloculina akneriana 0 0 0 0 0 0 0 0 0 0 o 0 0 0 

Quinqueloculina arctica 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Reophax spo 0 0 0 •• 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Stainforthia concava 0 0 0 0 0 0 0 0 0 0 0 0 o o o 0 0 0 0 

Stetsonia horvathi 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 

Textularia wiesneri . 0 0 0 0 0 0 0 • o o 0 0 0 0 0 • 0 o o 

Triloculina frigida 0 0 0 0 0 • 0 0 0 0 0 0 0 0 o o o 0 0 0 0 

Trochammina subglobigeriniformis 0 0 0 • 0 o o 

Valvulineria arctica 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 

Total number of specimens 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

13 

0 

0 

0 

82 

0 

3 

0 

0 

0 

0 

1 

0 

0 

314 

4 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

96 

0 

0 

0 

0 

0 

0 

3 

0 

0 

421 

7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

0 

0 

0 

88 

0 

0 

0 

0 

0 

0 

8 

0 

0 

743 

10 

0 

0 

0 

0 

0 

0 

0 

1 

0 

0 

0 

6 

0 

0 

0 

92 

0 

0 

0 

0 

0 

0 

I 

0 

0 

381 

14 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I 

0 

0 

0 

0 

92 

0 

0 

0 

0 

5 

0 

2 

0 

0 

313 

19 

0 

0 

0 

0 

0 

0 

0 

80 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

20 

0 

0 

0 

5 

24 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

25 

0 

75 

0 

4 

33 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

39.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

46 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

52.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

59 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

65.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

73.5 

0 

0 

0 

1 

0 

0 

4 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

6 

84 

0 

0 

0 

0 

96 

83 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

88 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

91 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

~ t""' 

tTl 

C/) 

If 

w 

~ 
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica . . . . . . . . . . . . . . . . ...... . 

Buccella frigida ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina reniforme ................. . 

Cassidulina teretis. . . . . . . . . . . . . . . . . . . . . 

Cribroelphidium excavatum ............ . 

Cribrostomoides sp. . ................. . 

Cyclammina sp ....................... . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Glomospira gordialis ................. . 

Haplophragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Quinqueloculina akneriana . ............ . 

Quinqueloculina arctica ............... . 

Reophax sp .......................... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Textularia wiesneri ................... . 

Triloculina frigida .................... . 

Trochammina subglobigeriniformis ...... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

93.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

97 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

102 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

107.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

69 

0 

0 

0 

0 

10 

0 

2 

0 

14 

0 

0 

0 

0 

116 

114 118 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

16 0 

0 0 

0 0 

0 0 

0 0 

22 66 

0 3 

2 3 

0 0 

0 0 

47 0 

0 0 

12 27 

0 0 

0 0 

1591 314 

125.5 

0 

0 

0 

0 

0 

7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

21 

14 

7 

0 

0 

36 

0 

0 

0 

0 

14 

130.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

3 

0 

0 

0 

31 

0 

41 

0 

3 

3 

0 

3 

0 

0 

29 

UnitM 

132.5 

0 

0 

0 

4 

0 

0 

0 

0 

0 

0 

9 

4 

0 

2 

0 

72 

6 

0 

0 

0 

4 

0 

0 

0 

0 

53 

M2 

136 139.5 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 

3 10 

0 0 

0 0 

0 

84 69 

0 0 

7 7 

0 

0 0 

0 0 

0 0 

5 11 

0 0 

0 0 

355 351 

·II> 

143 147.5 152 156.5 

0 0 1 

0 0 0 0 

0 0 0 0 

4 7 8 4 

0 0 0 0 

0 0 0 0 

1 0 0 

0 0 0 0 

0 0 0 0 

0 0 0 0 

2 25 12 6 

0 0 0 6 

0 10 7 

0 2 2 1 

0 0 0 0 

12 25 23 28 

1 0 0 0 

6 7 2 0 

0 0 0 17 

0 3 0 0 

69 16 34 21 

0 0 0 0 

0 11 

0 0 0 0 

3 4 4 

283 319 300 307 

165.5 

0 

0 

0 

3 

0 

0 

0 

0 

0 

0 

10 

1 

0 

34 

0 

0 

(} 

3 

11 

0 

3 

0 

29 

290 

174.5 

2 

0 

0 

19 

0 

0 

0 

0 

0 

0 

5 

4 

0 

0 

0 

42 

0 

0 

0 

0 

9 

0 

1 

0 

18 

332 

N 

00 

0 

I 

~ 

en 

~ 

~ 

~ 

~ 

~ 0 

~ ~~ 

ttl 

~ > en 

JZ 

en 

~ 

~ ~ 

B 

(") 

~ 
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica . . . . . . . . . . . . . . . . . . . . . . . 

Buccella frigida ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina reniforme ................. . 

Cassidulina teretis. . . . . ............... . 

Cribroelphidium excavatum ............ . 

Cribrostomoides sp ................... . 

Cyclammina sp ....................... . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Glomospira gordialis ................. . 

Haplophragmoides obscurus ............ . 

Oridorsalis spp ....................... . 

Quinqueloculina akneriana . ............ . 

Quinqueloculina arctica ............... . 

Reophax sp .......................... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Textularia wiesneri ................... . 

Triloculina frigida .................... . 

Trochammina subglobigeriniformis ...... . 

Valvulineria arctic a. . . . . . . . . . . . . . . . . .. . 

Total number of specimens ............. . 

179.5 

3 

0 

0 

15 

0 

2 

0 

0 

0 

0 

1 

0 

0 

0 

71 

0 

0 

0 

0 

4 

0 

0 

0 

4 

131 

184.5 

0 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

190.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

196.5 202.5 209.5 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

UnitM 

216.5 223 231.5 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

238.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

246.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

100 

0 

0 

0 

0 

0 

0 

0 

0 

0 

11 

I M3 I 

253 261 

0 1 

0 0 

0 1 

0 0 

0 0 

0 

0 1 

0 0 

0 0 

0 0 

0 

0 

0 

0 

0 

94 

0 

0 

0 

3 

0 

0 

0 

0 

0 

12 

3 

0 

0 

66 

0 

0 

0 

0 

10 

0 

2 

0 

2 

267 275 278.5 

2 0 

0 11 21 

1 1 

1 I 

0 0 0 

0 1 0 

1 0 0 

0 0 0 

0 0 0 

0 0 0 

0 

1 

0 

37 

0 

0 

0 

43 

0 

1 

0 

8 

0 

0 

0 

0 

0 

79 

0 

0 

0 

0 

0 

5 

0 

0 

0 

0 

0 

0 

0 

40 

0 

0 

0 

0 

27 

0 

7 

0 

1 

345 313 2107 354 337 

280.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

44 

0 

0 

0 

0 

53 

0 

0 

0 

0 

237 

~ ~ Cll 

~ 

~ 
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3-Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica . . . . . . . . . . . . . . . . . . . . . .. 

Buccella frigida ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina reniforme ................. . 

Cassidulina teretis. . . . . . . . . . . . . . . . . . . . . 

Cribroelphidium excavatum ............ . 

Cribrostomoides sp ................... . 

Cyclammina sp ....................... . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Glomospira gordialis ................. . 

Haplophragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Quinqueloculina akneriana . ............ . 

Quinqueloculina arctica ........... '· ... . 

Reophax sp .......................... . 

Stainforthia concava .................. . 

Stetsonia horvathi . . . . . . . . . . . . . . . . . . . . . 

Textularia wiesneri ................... . 

Triloculina frigida .................... . 

Trochammina subglobigeriniformis ...... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

283.5 

5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

82 

0 

3 

0 

0 

10 

0 

0 

0 

0 

39 

UnitM 

288.5 291.5 

0 

0 

14 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

86 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

296.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I Ll I 

306 310 

2 

0 

4 

0 

3 

0 

0 

0 

0 

0 

1 

2 

1 

0 

0 

66 

0 

0 

0 

10 

0 

8 

0 

0 

222 

0 

0 

0 

0 

0 

0 

13 

0 

38 

0 

0 

38 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

13 

0 

0 

8 

316 

0 

0 

20 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

79 

0 

0 

0 

0 

0 

0 

0 

0 

0 

85 

320 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

324 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

328 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

UnitL 

331.5 335 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

341 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

346.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

350 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Ll 

353 

0 

0 

0 

0 

0 

0 

50 

0 

0 

0 

0 

0 

50 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

357.3 

25 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

9 

6 

0 

0 

0 

0 

0 

0 

0 

56 

0 

0 

0 

0 

32 

w 

0 

I 

Cl.l 

I 

~ 

~ ~ 8 

~ 

~ t:J:j 

> Cl.l 

~ 

~ 

~ 

~ 

~ 
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3 -Continued. 

Lithostratigraphic unit 

Planktic foraminifer peak 

Sample depth (em) 

Bolivina arctica ...................... . 

Buccella frigida . ..................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina reniforme ................. . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Cribrostomoides sp ................... . 

Cyclammina sp ....................... . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Glomospira gordialis ................. . 

Haplophragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Quinqueloculina akneriana . ............ . 

Quinqueloculina arctica ............... . 

Reophax sp .......................... . 

Stainforthia concava .................. . 

Stetsonia horvathi .................... . 

Textularia wiesneri ................... . 

Triloculina frigida .................... . 

Trochammina subglobigeriniformis ...... . 

Valvulineria arctica ................... . 

Total number of specimens ............. . 

L2 

360 362.3 

0 38 

0 0 

0 0 

0 0 

0 8 

0 0 

0 14 

0 0 

0 0 

0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

8 

0 

0 

0 

0 

0 

0 

0 

30 

0 

0 

0 

0 

37 

365.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

370 373.5 

0 37 

0 0 

0 0 

0 0 

0 2 

0 0 

0 0 

0 0 

0 0 

0 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

19 

3 

0 

0 

0 

0 

0 

0 

0 

0 38 

0 0 

0 0 

0 0 

0 0 

0 129 

378.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

384.5 

0 

0 

0 

0 

20 

0 

40 

0 

0 

20 

0 

0 

20 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

5 

Unit L 

387.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

392.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I L3 I 

396.5 401.7 

0 63 

0 0 

0 0 

0 0 

0 0 

0 0 

8 10 

0 0 

0 0 

38 0 

0 

0 

4 

2 

0 

0 

0 

0 

0 

2 

44 

0 

0 

0 

0 

131 

0 

0 

6 

6 

0 

0 

0 

0 

0 

2 

10 

0 

0 

0 

0 

49 

406 413.5 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 

0 

25 

0 

75 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

4 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

422.5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

430;5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

434 

0 

0 

0 

0 

0 

0 

50 

0 

0 

0 

0 

0 

0 

0 

0 

50 

0 

0 

0 

0 

0 

0 

0 

0 

0 

2 

I Unit J 

440 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

t""' 

~ tr1 

C/) 

~ w 

w 

-
Table 3. Abundance, in percent, of selected benthic foraminifers in samples from Northwind Ridge core 3-Continued. 

Lithostratigraphic unit Unit J I Unit I 

Planktic foraminifer peak 

Sample depth (em) 445.5 449.5 454.5 461.5 465.5 469 482 492 493.8 515.5 541.5 569.5 

Bolivina arctica . . . . . . . . . . . . . . . . ...... . 

Buccella frigida ...................... . 

Bulimina aculeata .................... . 

Buliminella elegantissima .............. . 

Cassidulina reniforme . ................ . 

Cassidulina teretis . ................... . 

Cribroelphidium excavatum ............ . 

Cribrostomoides sp ................... . 

Cyclammina sp ....................... . 

Epistominella exigua .................. . 

Eponides tumidulus ................... . 

Fontbotia wuellerstorfi ................ . 

Globocassidulina subglobosa ........... . 

Glomospira gordialis ................. . 

Haplaphragmoides obscurus . ........... . 

Oridorsalis spp ....................... . 

Quinqueloculina akneriana . ............ . 

Quinqueloculina arctica ............... . 

Reophax sp .......................... . 

Stainforthia concava .................. . 

Stetsonia horvathi . . . . . . . . . . . . . . . . . ... . 

Textularia wiesneri ................... . 

Triloculina frigida .................... . 

Trochammina subglobigeriniformis ...... . 

Valvulineria arctica . .................. . 

Total number of specimens ............. . 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

25 

0 

0 

0 

0 

50 

0 

0 

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SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

Periodicals 

Earthquakes & Volcanoes (issued bimonthly). 

Preliminary Determination of Epicenh~rs (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. 

Circulars 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. 5- 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 reflect subsurface structures that are of 

economic or geologic significance. 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 .5-minute quadrangle photogeologic maps on planimetric bases that 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 blackand-white maps on topographic or planimetric bases for 

quadrangle or irregular areas at various scales. Pre-1971 maps 

show bedrock geology in relation to specific mining or mineraldeposit 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-and-white maps on topographic or planimetric 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, Map Distribution, Box 25286, Bldg. 810, 

Federal Center, 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 permanent 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 form 

only. 

"Price and Availability List of U.S. Geological Survey 

Publications," issued annually, is available free of charge in 

paperback booklet form only. 

Selected copies of a monthly catalog "New Publications 

of the U.S. Geological Survey" are 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, announcements, and publications may be incorrect. 

Therefore, the prices charged may differ from the prices in 

catalogs, announcements, and publications.