If yon do not need this publication after it has served your purpose, please return it to the 

Geological Survey, using the official mailing label at the end

UNITED STATES DEPARTMENT OF THE INTERIOR

GEOLOGY AND BIOLOGY OF 

NORTH ATLANTIC DEEP-SEA CORES

SUMMARY, FOREWORD, AND GENERAL INTRODUCTION

PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

PART 2. FORAMINIFERA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 196-A

UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Professional Paper 196-A

GEOLOGY AND BIOLOGY OF

NORTH ATLANTIC DEEP-SEA CORES

BETWEEN NEWFOUNDLAND AND IRELAND

SUMMARY OF THE REPORT

FOREWORD, BY C. S. PIGGOT 

GENERAL INTRODUCTION, BY W. H. BRADLEY

PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

By M. N. BRAMLETTE AND W. H. BRADLEY

PART 2. FORAMINIFERA 

By JOSEPH A. CUSHMAN AND LLOYD G. HENBEST

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1940

For eale by the Superintendent of Documents, Washington, D. C. ------- Price 30 cents

CONTENTS

Summary of the report-_____________________________

Foreword, by C. S. Piggot___________________________

General introduction, by W. H. Bradley.______________

Significance of the investigation._________________

Location of the core stations.____________________

Personnel and composition of the report___________

Methods of sampling and examination___________

Part 1. Lithology and geologic interpretations, by M. N. 

Bramlette and W. H. Bradley. _____________________

Examination and analysis of samples...___________

Acknowledgments__ _ _ _________________________

Presentation of data.___________________________

Stratigraphic units______________________________

Volcanic ash zones._________________________

Glacial marine deposits__--__-_---___--_____-

Correlation of zones represented in the cores.______

Interpretation of the glacial marine succession______

Sources of detritus._________________________

Temperature of the ocean, as indicated by the 

deposits.________________________________

Interpretation of the glacial marine zones in 

terms of stages or substages of the PleistocenePost-glacial climatic changes.____„___________

Rate of deep-sea sedimentation.__________________

Page

VII

XI

XIII

XIII

XIV 

XIV 

XIV

1

1

2

2

2

2

3

5

7

7

10

12

13

Part 1. Lithology and geologic interpretation—Contd. 

Evidence of bottom currents.____________________

Submarine slumping.___________________________

Carbonate content of the sediments_-_____. _______

Sulphates. _____________________________________

Siliceous organisms_____-______-__----____-_---

Role of mud-feeding organisms___________________

Mineralogy of the clastic sediments.______________

Spectroscopic tests._____________________________

Porosity of the sediments.-____.-__._-_________-.

Mechanical analyses.______________-__-______..--

Basaltic pyroclastics and their alteration___________

Volcanic rock in core ll______________-_-___-_--_

Basaltic mud in core 10________________________

Part 2. Foraminifera, by Joseph A. Cushman and Lloyd G. 

Henbest.________________________________________

Preparation of samples_____________-_______-__-_

Acknowledgments. __ _ _________________________

Distribution in the cores and list of species________

Pelagic Foraminifera-___________________________

Bottom-living Foraminifera___-_--__-.__-____-___

Bathymetric distribution._______________________

Temperature indications-________________________

Age and correlation__________________________.__

Page

14

15

17

21

21

22

23

25

26

28

30

32

32

35

35

35

35

39

46

48

49

49

ILLUSTRATIONS

Page 

PLATE 1. Bathymetric chart of a part of the North Atlantic Ocean showing the location of the core stations._______________ xv

2. Longitudinal sections of the air-dried cores---_--------__-----_-------_--------_-------------------------- xv

3. Diagram showing the lithology and correlation of lithologic zones in the cores___-__________-_____----_--_-_-_-.. 4

4. Diagram showing Cushman and Henbest's interpretation of water temperatures indicated by the pelagic Foraminifera- __-___-______„___-__________--_-__________-___-__-_______--__-_______--_---------.----------_ 4

5. A, Fecal pellets or filled borings in basaltic mud; B, Fecal pellets or filled borings in foraminiferal marl___________ 32

6. Standard pyramid diagram showing the size distribution, kinds of organisms, and mineral particles in four types of

sediment_ __-____________________________-___-________-____-___-___-_--_---------___--_----------- 32

7. A, Zeolite crystals in clayey rock; B, Upper surface of the clayey rock, which is interpreted as an alteration product 

of basaltic lava; C, Palagonite rims surrounding fragments of unaltered basaltic glass; D, Foraminifera shells 

replaced by a zeolite.____________________________-____-_______--___---_-_-----_---_----------------- 32

8-10. Foraminifera from the North Atlantic deep-sea cores____________-__________-_____---_--,_---_--__--_--_---_ 51-54

FIGURE 1. Profile across the North Atlantic Ocean bottom along the line of the numbered core stations-________-_--____--_ xiv

2. Diagram showing the inferred relations of glacial marine and nonglacial sediments____________________________ 8

3. Diagram showing three interpretations of the glacial marine zones in terms of stages and substages of the Pleistocene.---..---_--_---_-_-__-__------__-_---__--------_--_-----_---------------.--------------------- 10

4. Curve showing amplitude of solar radiation changes during the past 300,000 years___-__________--_---_------_ 12

5. Graph showing the CaO-CO2 ratios of core samples in relation to the CaO-CO2 ratio of pure calcite_ _____________ 17

6. Diagram showing distribution of volcanic ash shards in sediments._______-______-___-__________--_--_----_-- 22

7. Dehydration curves of basaltic mud from core 10, a red clay from the Pacific Ocean, and typical halloysite and

montmorillonite from clay deposits in the United States_____________-____-_________--_--_-_-_-____------ 24

8. Relation of calculated original porosity of blue mud in core 3 to depth below top of core _______________-_-_----- 27

9. Sketch of the two halves of the top part of core 3 showing differential shrinkage.____--______-___-_-__-.-_---_ 28

10. Curves showing size distribution of organisms and mineral particles in blue mud, a gravelly foraminiferal marl,

globigerina ooze, and clay________-___-_-_________-___--__-___-_-----_-_----_--------__-_------------ 29

11-21. Charts showing distribution and temperature significance of Foraminifera in the cores........________________ -- 36-45

in
IV CONTEXTS

TABLES

Page

TABLE 1. Geographic location, length of cores, and depth of the water from which they were taken___.----_-_----------- xiv

2. Grain-size distribution in sample B-53 from core 5 and approximate composition________________-_--_----_-_- 15

3. Distribution of magnesium carbonate within cores 3 to 13______-_______-_--_-__--__----_----_------------- 19

4. Lime-magnesia ratios of the samples shown in table 3_ _---._--__---------_----.----_--.-----_---------------- 21

5. Grain and lump density and porosity of dried mud from cores 3 and 10, ard calculated original porosity _,.___________ 27

6. Relative oxidation of iron in fresh and altered submarine basaltic glass-______________.________-_____-__--_--- 31

7. Analyses of mud from core 10 (sample W-15) and oceanic red cla3'S_____-__-__-_-____-___---_ _______________ 33
OUTLINE OF THE COMPLETE REPORT

Foreword, by C. S. Piggot.

General introduction, by W. H. Bradley.

PART 1. Lithology and geologic interpretations, by M. N. Bramlette and W. H. Bradley.

2. Foraminifera, by Joseph A. Cushman and Lloyd G. Henbest.

3. Diatomaceae, by Kenreth E. Lohnaan.

4. Ostracoda, by Willis L. Tressler.

5. Mollusca, by Harald A. Render.

6. Echinodermata, by Austin H. Clark.

7. Miscellaneous fossils and significance of faunal distribution, by Lloyd G. Henbest.

8. Organic matter content, by Parker D. Trask, H. Whitman Patnode, Jesse LeRoy Stimson, and John R. Gay.

9. Selenium content and chemical analyses, by Glen Edgington and H. G. Byers.

SUMMARY OF THE REPORT

In May and June 1936 Dr. C. S. Piggot of the Geophysical 

Laboratory, Carnegie Institution of Washington, took a series of 

11 deep-sea cores in the North Atlantic Ocean between the 

Newfoundland banks and the banks off the Irish coast. These 

cores were taken from the Western Union Telegraph Co.'s cable 

ship Lord Kelvin with the explosive type of sounding device 

which Dr. Piggot designed. In the fall of that year he invited a 

group of geologists of the United States Geological Survey to 

study the cores and prepare a report. Biologists of the United 

States National Museum, the University of Buffalo, and chemists of the United States Department of Agriculture cooperated 

in the investigation and contributed to the report.

The westernmost core of the series (No. 3) was taken in the 

blue mud zone, but all the others were taken in parts of the ocean 

where the bottom is blanketed with globigerina ooze. The 

shortest cores are No. 8, taken on the mid-Atlantic ridge in 1,280 

meters of water, and No. 11, taken where the core bit struck 

volcanic rock. The cores range in length from 0.34 to 2.93 

meters and average 2.35 meters. They were taken at depths 

ranging from 1,280 to 4,820 meters.

Lithology and geologic interpretations.—In about 20 representative samples from each core the percentages of calcium carbonate, 

clay and silt, and sand were determined and plotted, and the 

relative abundance of Foraminifera, coccoliths, and diatoms was 

estimated. Material between these guide samples was examined 

microscopically, especially in certain critical zones.

Two zones were noted in which silicic volcanic ash (refractive 

index near 1.51) is common. The upper ash zone was found in 

all the cores except No. 11, but the lower one was found only in 

the lower part of cores 4 to 7. In core 3 the upper ash zone is 

represented by shards scattered very sparsely all through the 

core, as this core, despite its length of 2.82 meters, apparently did 

not reach the bottom of the ash zone. The upper ash zone, 

together with other adjacent lithologic zones, serves to correlate 

the cores, and the lower ash zone, found west of the mid-Atlantic 

ridge, helps to confirm the correlation.

Besides the zones of volcanic ash four other zones distinctive in 

lithologic character were found. These zones are characterized 

by a relative abundance of sand and pebbles, by a smaller 

percentage of calcium carbonate, and by a sparsity of Foraminifera and coccoliths. They are distinctive also in texture. The 

pebbles are subrounded to angular and include a wide variety of 

rock types—sandstone, gneiss, soft shale, and limestone—of 

which limestone is the most common. Some of the pebbles are 

as much as 2 centimeters across. These zones are interpreted as 

glacial marine deposits formed during the Pleistocene glacial 

epoch, when continental glaciers were eroding the land. Drift 

ice from the continental glaciers apparently transported consideraable quantities of rock debris far out into the ocean basin.

Between the glacial marine zones found in the North Atlantic 

cores the sediments consist chiefly of foraminiferal ooze or marl, 

much like that which is forming today in the same area.

The uppermost glacial marine zone is represented in all the 

cores except Nos. 3 and 11 and lies just below the upper volcanic 

ash zone. In cores 4 to 7 the glacial zones are relatively thin and 

are spaced at approximately equal intervals; between the third 

and fourth glacial zones (in descending order) is the lower volcanic 

ash. East of the mid-Atlantic ridge only the uppermost glacial

zone has been identified. Other glacial marine deposits are 

recognizable but their correlation is less certain.

Three interpretations are offered as possible explanations of 

the four glacial marine zones. The first is that each glacial 

marine zone represents a distinct glacial stage of the Pleistocene 

and that each zone of foraminiferal marl separating two glacial 

marine zones represents an interglacial stage. This interpretation seems least probable of the three. The second interpretation 

is that the upper two glacial marine zones and the intervening 

sediment may correspond to the bipartite Wisconsin stage, 

whereas the lower two represent distinct glacial stages of the 

Pleistocene separated from each other and from the zone representing the Wisconsin stage by sediments that, represent interglacial epochs no greater in length than postglacial time. This 

interpretation seems to imply too short a time for most of the 

Pleistocene epoch. The third interpretation, which is favored 

by the authors, is that each of the four glacial marine zones 

represents only a substage of the Wisconsin stage. This implies 

that the North Atlantic at approximately 50° north latitude for 

comparatively long periods of time alternately contained an 

abundance of drift ice and then was quite, or nearly, free of ice, 

while on land a continental ice sheet persisted, though it alternately waned and grew.

In the four cores in which the postglacial sediments are 

thickest the pelagic Foraminifera, according to Cushman and 

Henbest, reveal an interesting condition. These organisms 

indicate that during the middle part of the postglacial interval 

the temperature of the surface water in that part of the North 

Atlantic was somewhat higher than prevails today.

On the assumptions that the top of the uppermost glacial 

marine zone represents the beginning of the postglacial epoch as 

defined by Antevs, and that this was probably as much as 9,000 

years ago, the postglacial sediment in these cores accumulated 

at a rate of about 1 centimeter in 265 years; but, because the sea 

probably cleared of detritus-laden drift ice long before the land 

in the same latitude was cleared of the retreating continental 

ice sheet, the average rate of accumulation may have been as 

low as 1 centimeter in 500 years.

Coarse-grained sediment on the tops of ridges and fine-grained 

sediment in the deeper basins indicate that currents move across 

these ridges with sufficient velocity to winnow out the finer 

particles and sweep them into deeper basins beyond.

The fact that the glass shards in the volcanic ash zones have 

been reworked and distributed without any gradation in size 

through many centimeters of the overlying sediments leads us 

to believe that mud-feeding animals are continually working over 

these shards and other particles of sand and silt so that they are 

redistributed at successively higher levels. The shards and other 

particles may also be reworked by gentle bottom currents that 

move the material from mounds and ridges on the sea floor and 

drift it about over the adjacent flatter areas.

Several layers in the cores are sharply set off by the coarser 

grain size of the sediment or by a regular gradation in grain size 

from coarsest at the base to fine at the top. These may be a 

result of submarine slumping.

The term globigerina ooze is used loosely in this report to 

designate sediment, half or more than half of which, by weight, 

consists of Foraminifera. This usage accords more closely with

VII
VIII SUMMARY OF THE REPORT

the usage adopted by Correns in the Meteor reports than with 

the usage of Murray and Chumley in the Challenger reports, 

which was based solely on the carbonate content. Limy muds 

containing a lesser but still conspicuous number of Foraminifera 

are referred to as foraminiferal marl. The carbonate content 

of the globigerina ooze in these cores ranges from 46.6 to 90.3 

percent and averages 68.2 percent. In 191 samples representing 

all the lithologic types, the carbonate content ranges from 10.0 

to 90.3 percent and averages 41.3 percent. Coccoliths are 

abundant in many parts of the cores, but by reason of their small 

size they rarely make up as much as 10 percent of the sediment. 

Pteropods are rather numerous in parts of the cores taken on the 

mid-Atlantic ridge and on the continental slope off the Irish 

coast.

Most of the calcium carbonate in these sediments consists of 

the tests and comminuted fragments of calcareous organisms. 

The finest particles of carbonate are of indeterminate origin, but 

their irregular shape and range in size suggest that they are 

largely the finest debris of the comminuted organisms rather 

than a chemical precipitate. Clusters or rosettes of calcium 

carbonate crystals were found in many samples, but they are not 

abundant. They evidently formed in the mud on the sea floor.

No conclusive evidence of an increase in magnesium carbonate 

with depth was found, though some of the data suggest it. The 

magnesium carbonate is somewhat more abundant in the glacial 

marine zones than elsewhere, but its concentration in those zones 

is probably accounted for by the presence of clastic grains and 

pebbles of dolomite.

Diatom frustules, radiolarian skeletons, and sponge spicules 

are the most common siliceous organic remains found in the 

cores, and these generally form less than 1 percent of the sediment. One notable exception is the sediment in the middle part 

of core 9, just east of the mid-Atlantic ridge, which contains 50 

percent or more of diatoms.

Ellipsoidal and elongate or cylindrical pellets that appear to 

be fecal pellets are plentiful in the mud at the tops of cores 10 

and 12, taken in the eastern part of the North Atlantic, but 

were not found elsewhere. No attempt was made to identify 

them further.

The sand-size material showed no marked variation in the 

mineral composition of the clastic grains at different horizons 

within individual cores and no conspicuous lateral variation 

from core to core. The mineral grains in the sand-size portions 

were not separated into light and heavy fractions, but simple 

inspection showed that grains of the heavy minerals are somewhat more common in the glacial marine deposits than elsewhere. Well-rounded sand grains are sparsely scattered through 

all the cores, but they are rather more plentiful in the glacial 

marine zones. These grains, which range in diameter from about 

0.1 to 1.0 millimeter and average 0.5 millimeter, have more or 

less frosted surfaces. They may have been derived from the 

reworking of glacial marine deposits or they may have been 

rafted by seaweeds. Little was done with the clay minerals 

other than to note that most of them have the optical properties 

of the beidellite or hydrous mica groups.

Six samples were tested with a 10-inch spectograph, which 

revealed the presence of appreciable amounts of barium and 

somewhat less of boron in each sample. All the samples gave 

negative tests for antimony, beryllium, bismuth, cadmium, germanium, lead, silver, tin, and zinc.

The original porosity of several samples in core 3 was calculated from the porosity of the dried samples. The original 

porosity plotted against depth in the core seems to indicate that 

fine-grained blue muds buried to a depth of 2 or 3 meters in the 

ocean floor are appreciably compacted.

Partial mechanical analyses of nearly 200 samples were made 

and plotted, but only four complete mechanical analyses were

made. The complete analyses were made by the sedimentation 

method and include four distinctive types of sediment.

Pumiceous fragments and smaller shards of basaltic volcanic 

glass (index of refraction near 1.60) are scattered throughout all 

the cores, but are somewhat more common east of the mid-Atlantic ridge than west of it. Unlike the alkalic volcanic ash it 

shows no conspicuous concentration in zones. Most of the basaltic glass and pumice has a thin surface alteration film of palagonite. The films are thickest on fragments in cores taken from 

ridges where oxygen-bearing waters had free access to the sediments. Two varieties of palagonite are recognized.

Core 11 represents only 34 centimeters of the sea floor because 

the core bit encountered deeply altered olivine basalt. About 

15 centimeters of globigerina ooze rests on and within irregular 

cavities of the upper surface of a mass of clay that is apparently 

altered basalt. This clay is impregnated with manganese and 

contains nodular lumps of altered basalt. Part of the basalt 

near the base of the core is less altered. The clay contains scattered grains of sand and foraminiferal shells in which the original 

calcium carbonate has been replaced by a zeolite resembling phillipsite. This core may have penetrated the upper, deeply altered 

part of a submarine lava flow, but the evidence is not conclusive.

Core 10 contains two rather thick beds of distinctive clayey 

mud. About half of this mud is a beidellite or hydrous mica 

type of clay and the other half is made up of silt-size particles of 

basaltic glass, magnetite, augite, and calcic plagioclase. It 

contains very little common clastic material and exceedingly 

few Foraminifera. The composition and texture suggest that 

this mud was derived largely from a submarine volcanic eruption 

that threw into suspension clay particles perhaps partly from the 

normal sediment and from deeply altered basalt. A complete 

chemical analysis of this mud is given.

Foraminifera.—From these cores 184 samples representing 

every lithologic zone were examined for calcareous fossils. All 

but five samples contained Foraminifera. As in existing oceans 

deeper than several hundred meters, pelagic Foraminifera greatly 

outnumber the bottom-dwelling forms, though in variety of form 

and. in number of genera and species the bottom forms greatly 

exceed the pelagic. Several zones of relatively pure globigerina 

ooze were found, and many in which the ooze was clayey or sandy. 

Though variations in temperature were reflected by faunal 

changes, the general bathymetric facies of the faunas appear to be 

rather uniform throughout each core. The bottom faunas are 

least varied and prolific in cores from the deepest water, whereas 

in cores from the shallowest water they are by far the most 

varied and prolific. Cores from intermediate depths contain 

faunas of intermediate bathymetric facies. These relations to 

depth are, in general, characteristic also of faunas in the existing 

oceans. A few scattered specimens of Elphidium or Elphidiella 

were found. These genera thrive in shallow water, but in these 

cores the shells are so rare, so erratically distributed, and in some 

so poorly preserved that it seems probable they were rafted in by 

seaweeds or ice and therefore have no significance as indicators of 

depth. No species peculiar to the Miocene or Pliocene were 

found. It appears, therefore, that all the sediments penetrated 

by the cores are younger than Pliocene. Alternation of faunas 

that are characteristic of the warm and cold climates of the 

present day indicates great climatic changes during the time 

represented by these cores. The foraminiferal facies characteristic of cold and warm climates correlate with the alternating 

sequence of glacial-marine and warmer-water sediments indicated 

by the lithology. This correlation suggests that all the sediments in these cores are of Recent and Late Pleistocene age.

Diatomaceae.—Fifty-two species and varieties of diatoms were 

found in these cores. A large percentage of the species are neritic, 

warm-water forms that are foreign to the region today. Several
SUMMARY OF THE REPORT IX

alternations of warm-water and cold-water diatom floras occur 

in most of the cores, but their position in the cores is not in 

accord with the alternations of temperature inferred from lithology and foraminiferal facies. It is suggested that this disagreement may be due to the much longer settling time of the diatoms 

and that allowance should be made for it. The time equivalent 

of this difference of phase, as calculated from the vertical displacement necessary for the best approximation to agreement 

between the foraminiferal and lithologic data on the one hand 

and the diatom data on the other is of the order of 23,000 years. 

This figure appears absurdly high and a figure of several hundred 

years, based on extrapolation of experimentally timed settling 

in a relatively small vessel, is considered more reasonable. The 

action of cold and warm currents, some surficial and some deep 

seated, is suggested as the possible cause of the apparently erratic 

distribution of the diatoms. The possibility that the phase difference of 23,000 years mentioned above is related to shifts of 

ocean currents caused by advances and recessions of drift ice is 

offered as a speculation. Of 52 species and varieties illustrated, 

2 species and 1 variety are described as new.

Ostracoda.—In preparing a series of samples from the cores for 

the study of the Foraminifera about 175 specimens of Ostracoda 

were f<^und. These belong to 13 genera and 27 species, all living 

forms, though 12 of the species are known also as fossils. Most 

of the ostracodes were found in three cores that were taken in 

tbe shallowest water (1,280 to 3,230 meters). One of these cores 

(No. 8) was from the top of the mid-Atlantic ridge and tbe other 

two (Nos. 12 and 13) were from tbe continental slope southwest 

of Ireland. In the cores from deeper water (3,250 to 4,820 

meters) ostracodes were scattered very sparsely. Like most 

marine ostracodes, all the species found in the cores are bottom 

dwellers. Most of the species are decidedly cold-water forms 

that are found in tropical waters only at great depth, where the 

temperature is near freezing. Northern forms predominate; only 

2 of the species have not previously been known from northern 

waters, and 10 species are definitely Arctic forms. A few species 

that have a wider temperature range live not only in cold waters 

but also in the deep warm water of the Mediterranean.

The predominance of distinctly cold-water ostracodes and the 

prevalence of Arctic forms suggest that the temperature of the 

water in this part of the North Atlantic was formerly somewhat 

lower. But, as might be expected from the fact that all the 

species in these cores are bottom dwellers, their distribution in 

the cores shows no evident relationship to the cold and warm 

zones indicated by the composition and texture of the sediments 

and by the pelagic Foraminifera.

Mollusca.—The mollusks recovered from these cores can be 

divided into two groups, the pteropods and the other gastropods 

and pelecypods. The pteropods are by far the more numerous. 

All the specimens of the pelecypods and gastropods, other than 

pteropods, are representatives of deep-water species that are now 

living in the same boreal or cold-temperate waters. Also, the 

fragments that could not be identified specifically belong to forms 

that have congeners now living in these waters. The fauna of 

these cores, even that taken from the lower parts of the cores, 

shows no appreciable difference from that now living in the same 

localities. Among these mollusks no evidence of shallower or 

considerably deeper water is demonstrable. Molluscan remains, 

other than those of pteropods, are too scarce to attempt to 

differentiate cold- and warm-water facies, as was done with the 

foraminiferal faunas.

The Pteropoda, which are far more abundant in the cores than 

the other mollusks, belong to two genera and three species. One 

of the species is new. The geographic distribution of the pteropods is limited more by the temperature of the surface water 

than by any other factor. Nevertheless, as one species is cosmopolitan, one boreal, and one a new species thought to be the

northern analogue of a more southern species, and as all three 

species occur together, they have no significance for differentiating cold- and warm-water facies. These organisms are pelagic 

and their shells have a rather wide distribution, but, as they are 

found on the sea floor at depths ranging from 247 to 3,750 meters, 

they are of little aid as indicators of depth of the ocean at the 

time these deposits were laid down.

Echinodermata.—The remains of 9 species of Echinodermata 

were found in the cores. These include 1 ophiuroid, 7 echinoids, 

and 1 crinoid. No remains of asteroids were found. All the 

echinoderms found belong to species now living in that part, or 

adjacent parts, of the North Atlantic. Echinoderm remains are 

rather uniformly distributed among the cores, but they are most 

numerous in core 8, which was taken in 1,280 meters of water 

on the crest of the mid-Atlantic ridge. By far the commonest 

species is Pourtalesia miranda, remains of which were found in 

nearly two-thirds of the 82 echinoderm-bearing samples and in 

all the cores except 8 and 11.

Because the association of species in the cores is closely 

similar to the association of living species in that part of the 

North Atlantic and because the association of species within each 

core is independent of the distance below the top of the core it 

appears that neither the distribution nor the composition of the 

echinoderm fauna has changed significantly during the interval 

represented by these cores. No evident relationship was found 

between the distribution of the various species of echinoderms 

and the cold- and warm-water facies of the sediments indicated 

by both the Foraminifera and the lithology.

Miscellaneous fossils and significance of faunal distribution.— 

The principal fossil groups represented in the cores, listed in 

order of abundance, are foraminifers, diatoms, echinoids, siliceous 

sponges, radiolarians, ophiuroids (spines and plates), ostracodes, 

and pteropods. Remains of barnacles, brachiopods, pelecypods, 

holothuroids, bryozoans, gastropods, and teleost fishes (otoliths) 

were also found, but all these are rare. The foraminifers, diatoms, ostracodes, echinoderms, pelecypods, and gastropods were 

studied separately by specialists. The other groups are briefly 

noted and illustrated for the sake of the record. The most 

varied and prolific faunas were found in the three cores that 

were taken from the shallowest water and the least varied and 

least prolific were found in those from the deepest water. The 

bottom-living faunas throughout each core have a broadly similar bathymetric facies, and the bathymetric facies of each core 

appears to correspond to that of the fauna now inhabiting that 

locality. Faunas having the characteristics of very shallowwater marine faunas are either absent or, if present, are so rare 

and erratically distributed that they appear to be foreign in 

origin rather than indigenous. Ostracodes and pteropods are 

locally abundant in the cores from the shallower water, but are 

absent or rare at all horizons in those from the deeper water. 

The distribution and bathymetric facies of the faunas weigh 

heavily against the hypothesis of extreme changes in ocean 

level during the later part of the Pleistocene.

Organic matter content.—The content of organic matter, as 

determined from 123 samples, ranges from 0.1 to 1.0 percent of 

the total weight of the sediments, and the average is about 0.5 

percent. As in near-shore sediments, it is influenced by the 

configuration of the sea bottom. It is small on ridges and large 

in the deeps. It is particularly large in the sediments at the 

base of the east slopes of ridges, owing in part, probably, to 

material washed from the vicinity of the ridges by eastwardsweeping ocean currents. The organic matter content of the 

upper layers of the sediments in the abyssal deeps is greater 

for a few hundred miles east of the mid-Atlantic ridge than it 

is for a similar distance west of the ridge. The organic content 

does not vary consistently with depth except in core three, 

taken at the foot of the continental slope east of the Grand
X SUMMARY OF THE REPORT

Banks, where it seems to decrease about 25 percent in the first 

1.5 meters. The organic matter content of the sediments tends 

to be greater in the warm zones, than in the cold zones, and in 

general it is slightly greater in sediments which, according to 

Cushman's determination of the Foraminifera, were probably 

deposited in areas in which the surface water was relatively 

warm. The organic content is rather closely related to the 

texture, and increases with increasing fineness of the sediments. 

The rate of deposition of organic matter is greater east of the 

mid-Atlantic ridge than west of it, presumably owing in part 

to a greater supply of plankton and in part to a slower rate of 

decomposition of the organic matter after it is laid down in the 

sediments. The slower rate of decomposition within the sediments is inferred from the greater state of reduction of the 

sediments, which is indicated by the nitrogen-reduction ratio. 

The nitrogen-reduction ratio suggests a slight increase in state 

of reduction with increasing depth of burial in the upper part 

of the deposits, but indicates no significant change in the lower 

part. The percentage of organic content tends to increase as 

the percentage of Foraminifera in the sediments decreases, but 

it shows no relationship to the calcium-carbonate content.

Selenium content and chemical analyses.—As a part of a comprehensive investigation of the distribution of selenium in marine

sediments and soils derived from them complete fusion analyses 

were made of 20 samples from the suite of 11 cores. These 

samples were taken from the tops of the cores and at intervale of 

approximately 1 and 2 meters below the top. In addition, 1 

core taken on the continental shelf off Ocean City, Md., and 3 

cores from the Bartlett Deep were sampled and analyzed, making 

a total of 31 analyses. The results of the analyses include all 

the normal analytical data obtained in a so-called complete soil 

analysis by the fusion method, and, in addition, determinations 

of organic matter, nitrogen, chlorine (in all but 12 analyses), 

hygroscopic water, and selenium. All the samples were analyzed 

with the entrained sea salts. The core from the continental 

shelf off Ocean City contained the most selenium—at the top 

0.6 part per million, at 1 meter 1.0, and at 2 meters 2.0 parts per 

million. The samples from the North Atlantic cores showed a 

selenium content ranging from 0.06 to 0.8 part per million. Of 

the samples from the Bartlett Deep one contained 0.2 part per 

million of selenium, but all the others contained lees than 0.08 

part per million. No evidence was found of a relation between 

the selenium content and volcanic activity.

The silica-sesquioxide and silica-alumina ratios are tabulated 

and their significance as means of comparing the analyses is 

discussed.
FOREWORD

By C. S. PIGGOT »

During the last cruise (1927-29) of the nonmagnetic 

ship Carnegie of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington a 

number of samples of the deep ocean bottom were 

obtained by means of the telegraph snapper. The 

Geophysical Laboratory determined the radium content 

of these samples and found that they contained a concentration of radium 2 as astonishingly high as that 

reported by Joly 3 and Pettersson 4 from similar samples 

taken by the Challenger and Princess Alice II. This 

high radium concentration in the surface layer of the 

oceato. bottom, which constitutes 72 percent of the surface of the globe, raises questions of great significance 

to both oceanography and geophysics. An obvious 

question is whether radium in so high a concentration is 

present down through all deep-sea sediments or only 

at the surface.5 If the first hypothesis is correct it 

indicates the presence of uranium throughout the sediments, whereas the second indicates the existence of 

radium itself, presumably separated out from the sea 

water. The study of this question requires samples of a 

type analogous to the cores so extensively used in subsurface exploration on land. Inquiries among oceanographic organizations established the fact that although 

some cores a meter or more in length had been obtained 

from relatively shallow water, many of them were much 

distorted by the time they reached the laboratory, and 

none as long as 1 meter had been obtained from a depth 

of 4,000 meters or more.6 Those engaged in such research 

emphasized the need of apparatus capable of obtaining 

undistorted cores from great depths. In 1933 the 

Council of the Geological Society of America approved a 

grant for the development of such apparatus.7 Fortunately, cooperation was obtained from several special

i Geophysical Laboratory, Carnegie Institution of Washington.

> Piggot, C. 8., Radium content of ocean-bottom sediments: Am. Jour. Sci., 5th 

ser., vol. 25, pp. 229-238,1933.

a Joly, J., On the radium content of deep-sea sediments: Philos. Mag., vol. 16, pp. 

190-197,1908.

4 Pettersson, Hans, Teneur en radium des depots de mer profonde: Resultats de 

Campagnes Scientiflques par Albert I« Prince Souverain de Monaco, vol. 81,1930.

« Piggot, C. S., op. cit., p. 233.

* Since these inquiries were made D. Wolansky has published her review in the 

Qeologlsche Rundschau (Band 24, Heft 6, p. 399,1933), in which she refers to the work 

of A. D. Archanguelsky in the Black Sea (Soc. Naturalistes Moscow Bull., new ser., 

vol. 35, pp. 264-281,1927). Wolansky mentions cores 3 to 4 meters long from depths 

of 2,237 meters. See also Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 

1925-27, Band 3, Teil 2, Lief. 1, pp. 4-28,1935.

' Piggot, C. S., Apparatus to secure core samples from the ocean bottom: Geol. 

Soc. America Bull., vol. 47, pp. 675-684,1936.

agencies, particularly the Burnside Laboratory of the 

E. I. du Pont de Nemours, whose ballistics expert, Dr. 

B. H. Mackey, offered fundamental suggestions and 

made many essential calculations and tests; also the 

United States Bureau of Lighthouses, from whose lightship tender, the S. S. Orchid, many experimental soundings were made. Several forms of the apparatus were 

developed and tested, and in August 1936 14 satisfactory 

cores were obtained from the canyons in the continental 

shelf off New Jersey, Delaware, and Maryland, and 

another from the ocean floor below 2,500 meters of 

water.8 This first deep-sea test was made possible by 

the cooperation of the Woods Hole Oceanographic 

Institution and was carried out in connection with an 

investigation of the submarine canyons by H. C. Stetson 

of that institution. This test demonstrated the feasibility of the apparatus as built but suggested some 

minor changes in design. These were incorporated in 

another apparatus, which was put aboard the cable ship 

Lord Kelvin at Halifax, Nova Scotia. Through the 

courtesy of Mr. Newman Carlton, Chairman of the 

Board of Directors of the Western Union Telegraph Co., 

the Carnegie Institution of Washington was invited to 

have a member of its staff accompany the Lord Kelvin 

while that ship was engaged in making repairs to the 

North Atlantic cables, in order to test the apparatus in 

deep water. This offer was gladly accepted, and in 

May and June of 1936 I was on board the Lord Kelvin 

with the apparatus.

Because of the personal interest and cooperation of 

the commanding officer, Lt. Com dr. Bredin Delap, 

Royal Navy, retired, the undertaking was more successful than had been anticipated, and a suite of 11 

excellent cores was obtained, extending from the Grand 

Banks of Newfoundland to the continental shelf southwest of Ireland.

All but two of these cores (Nos. 8 and 11) are more 

than 2.43 meters (8 feet) long, and all contain ample 

material for study. Of the two short cores, No. 8 was 

taken from the top of the Faraday Hills, as that part 

of the mid-Atlantic ridge is known, where the material 

is closely packed and more sandy and consequently 

more resistant; No. 11 came from a locality where the

• Cushman, J. A., Henbest, L. G., and Lohman, K. E., Notes on a core sample from 

the Atlantic Ocean bottom southeast of New York City: Geol. Soc. America Bull., 

vol. 48, pp. 1297-1306, 1937.

XI
XII FOREWORD

apparatus apparently landed on volcanic rock that may 

be part of a submarine lava flow. Soundings at the 

localities where the cores were taken show depths ranging from 1,280 meters at the top of the Faraday Hills to 

4,820 meters in the deep water between the mid-Atlantic 

ridge and the continental shelf.

The thorough test made possible by the interested 

cooperation of everyone on board the Lord Kelvin fully 

demonstrated the capacity of the apparatus and produced material from strata of oceanic sediments deeper 

than have ever before been available.

In order that this pioneer material might be examined to the best advantage and an adequate estimate 

made of the potentialities of cores of this type, a group of 

investigators representing various fields of science was 

invited to examine them. Efforts have been made to 

arrange the sequence of these investigations in such a 

way that the maximum information may be obtained 

with the minimum destruction of the samples.

The cores are now at the Geophysical Laboratory of 

the Carnegie Institution of Washington, where they and 

others that may be obtained by this laboratory will be 

held available for further research.
GENERAL INTRODUCTION

By W. H. BRADLEY

SIGNIFICANCE OF THE INVESTIGATION

The long cores of deep-sea sediment considered in 

this report represent a longer span of the earth's late 

geologic history, as recorded in abyssal sediments, than 

has been heretofore accessible. In a measure, therefore, this study has been exploratory. Because of that exploratory aspect we have not only presented the observations but also have deliberately speculated upon various 

possible interpretations of the features observed in the 

cores and upon their relations with one another. Becaus^e the cores are few in number and widely spaced, 

we offer many of the interpretations not as definite 

conclusions but rather as suggestions to be tested by 

whatever coring may be done in the future in that part 

of the North Atlantic.

From this investigation it appears that glacial marine 

deposits may prove to be sensitive indicators of the climatic changes that caused the growth and decay of 

continental ice sheets during the Pleistocene. In particular, it seems that the glacial marine record may 

throw light on the climatic fluctuations that determined substages of the Pleistocene. The marine 

record was the result of a continuously operating series 

of causes such that the deposits of each glacial substage 

were separated from one another by the deposits of the 

intervening warmer substage. The record of each 

substage has remained intact and was not obliterated 

by readvances of the ice. As the equatorward extent 

of the glacial marine deposits implies a corresponding 

expansion of continental ice sheets, the extent of the 

deposits may be used as a measure of the intensity of 

the climatic changes, and their thickness may be used 

as a rough indicator of the duration of glacial substages. 

Similarly, the thickness and poleward extent of tongues 

of nonglacial sediment—the foraminiferal marl—are 

measures of deglaciation. The area! extent of these 

tongues of sediment can be determined by additional 

cores taken at properly located stations.

When the glacial marine record is more fully known 

it should provide a basis for correlating the Pleistocene 

history of Europe and North America.

Cores taken along the meridians in series extending 

from the Arctic regions into the tropical parts of theAtlantic should make it possible to map the southern 

limits of pack ice in the sea during successive glacial 

maxima, at least for the later part of the Pleistocene.

As the pelagic Foraminifera in these abyssal sediments 

are reliable indicators of surface-water temperatures in 

the Recent and Pleistocene epochs, it should be possible 

to trace southward into the tropics layers or beds of 

foraminiferal ooze that are the time equivalents of 

glacial marine zones. Such layers of foraminiferal ooze 

could then be correlated with the layer of globigerina 

ooze in the tropics that Schott 9 identified as a relatively cold-water, deposit that probably represents the 

last glacial epoch of the Pleistocene.

The study of climatology as well as geology may be 

advanced by the information to be derived from long 

sea-bottom cores. Significant evidence bearing on postglacial climatic changes may be obtained from minutely 

detailed study of the Foraminifera in cores taken in 

parts of the ocean where postglacial sedimentation has 

been comparatively rapid, as, for example, near the 

seaward edge of the blue-mud zone. On the assumption that such sediment accumulates at an essentially 

uniform rate, climatic fluctuations may be located approximately hi time within the postglacial interval and 

may be correlated from place to place along the ocean 

margins from the Arctic to temperate or even tropical 

latitudes and perhaps also from continent to continent.

Archeology, also, might profit from the knowledge 

of a relatively timed and correlated sequence of climatic changes, for such changes may well ha^e made a 

significant impress on the habits and migrations of 

peoples, particularly those that dwelt in regions where 

small changes in either temperature or rainfall were 

critical. As I have pointed out in an earlier paper, 10 

students of archeology and early history, particularly in 

the Mediterranean region, might profit much from 

detailed studies of long cores of the sediment in the 

deep basins of the Mediterranean. In cores from that 

sea, as elsewhere, changes ID the foraminiferal faunas 

would indicate climatic changes, and the sediments 

would yield, in addition, evidence of volcanic eruptions 

and earthquakes. The time when the Sahara became 

a desert should also be recorded in the Mediterranean 

sediments by wind-blown sand. Such a change might 

conceivably be integrated with the wealth of archeo-

' Schott, W., Die Foraminiferen in dem aquatorialen Teil des Atlantischon Ozeans:. 

Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 3, Lief. 1, 

pp. 120-128, 1935.

1° Bradley, W. H., Mediterranean sediments and Pleistocene sea levels: Science 

new ser., vol. 88, pp. 37C-379, 1938.

XIII
XIV GENEEAL INTRODUCTION

logical records of the region, and the later volcanic 

eruptions and earthquakes might be correlated with 

early history.

Some of the problems sketched so briefly here are 

touched upon in the several chapters of this report, 

but most of them must be left for future investigators. 

Nevertheless, methods by which such problems may 

be attacked are described and discussed at considerable 

length, particularly in the chapters on "Lithology and 

geologic interpretations" and "Foraminifera."

LOCATION OF THE CORE STATIONS

The cores were taken along a slightly irregular line 

between the easternmost part of the Newfoundland 

Banks and the banks off the southwest coast of Ireland, 

as shown in plate 1. Each core obtained by the Piggot 

coring device is numbered to correspond with the station 

number of the cable ship Lord Kelvin. Stations 1 and 

2 were trial stations at which preliminary tests were 

made to familiarize the crew with the apparatus, and 

no cores were preserved. The 11 cores studied are 

numbered consecutively, 3 to 13. The relation between

M. N. Bramlette, J. A. Cushman, L. G. Henbest, K. E. 

Lohman, and P. D. Trask. As the biologic phase of 

the work progressed it became evident that other 

organisms than the foraminifers and diatoms should be 

studied. Accordingly Mr. Henbest invited Dr. Willis 

L. Tressler, of the University of Buffalo, to examine the 

ostracodes, Dr. Austin H. Clark of the United States 

National Msueum, to examine the echinoderms, and 

Dr. Harald A. Kehder, also of the United States 

National Museum, to examine the mollusks.

The organic matter content of the sediments was 

studied by Mr. Trask in collaboration with Messrs. 

H. Whitman Patnode, Jesse LeRoy Stimson, and John 

R. Gay, all members of the American Petroleum 

Institute.

As part of a comprehensive research project on the 

distribution of selenium in marine sediments and the 

soils derived from them Dr. H. G. Byers and Mr. Glen 

Edgington, of the Bureau of Chemistry and Soils, 

Uuited States Department of Agriculture, made complete chemical analyses of 20 samples from these deepsea cores. These analyses, together with analyses of

w.

ST. JOHNS 

NEWFOUNDLAND 

Meters

5,000

MID-ATLANTIC RIDGE 

" FARADAY HILLS" 

6 789

E.

LANDS END 

ENGLAND

FIGUBE 1.—Profile across the North Atlantic Ocean along the line of the numbered core stations shown on plate 1.

the core stations and the submarine topography is 

shown in figure 1, which is a profile along the dashed 

line in plate 1 that connects the stations and extends 

from St. Johns, Newfoundland, to Lands End, England. 11

TABLE 1.—Geographic location, length of the cores, and depth of 

the water from which they were taken

Core number

3—. ..—..„— .....................

4— ...... ........... —__-—__-____

5— ._—..-.. — _._.___..-.______.._.

6— -—....__-_.___._.___..._„_...__

7.— ..—..„— ............ .........

8..— —_-___—.__._.___-.____..____

9— .................... ..... ....

10.... ................................

11....................................

12— .................................

13— .................................

Depth 

of water 

(meters)

4,700

3,955

4,820

4,125

3,250

1,280

3,745

4,190

4,820

3,230

1,955

Length 

of core 

(meters)

2.81

2.71

2.82

2.90

2.62

1.24

2.76

9 07

.34

2.43

2.21

Lat. N.

46°03'00"

48°29'00"

48°38'00"

J.Q°fWW

49°32'00"

49°36'00"

49°40'00"

A.QoAKff\(}ff

48°38'00"

49°37'00"

AQO'iQ'nn"

Long. W.

jQOoq'Afl//

35°54'30"

36°01'00"

39°4d/*>ft"

29°21'00"

28°54'00"

28°29'00"

OQOQft'Qfi"

17°09'00"

1 3o34/fW'

IQOoC'fWV'

PERSONNEL AND COMPOSITION OF THE REPORT

At the request of Dr. C. S. Piggot, of the Geophysical 

Laboratory of the Carnegie Institution of Washington, 

the following six members of the United States Geological Survey undertook a systematic study of the 11 

deep-sea cores from the North Atlantic: W. H. Bradley,

11 Data for plate 1 and figure 1 were taken from International Hydrograpbic Bureau, 

Carte Generate Bathymfitrique des Oceans, 3d ed., sheets A-l and B-l, copies of 

which were furnished by the TJ. 8. Hydrographic Office.

samples from several other deep-sea cores and a discussion of the occurrence of selenium, are included in 

the chapter on "Selenium content and chemical 

analyses."

METHODS OF SAMPLING AND EXAMINATION

The Piggot coring device 12 takes the cores in brass 

sampling tubes that have an inside diameter of 4.9 cm. 

As soon as a core is taken, the tube is cut off at the 

approximate length of the core and sealed. The cores 

here discussed were opened under Dr. Piggot's direction 

at the Geophysical Laboratory of the Carnegie Institution of Washington. A longitudinal cut was made 

along one side of each brass core barrel by means of a 

milling cutter so adjusted that it did not cut quite 

through the wall of the tube. The thin strip remaining 

was then ripped out without letting brass chips get 

into the core. After allowing the mud cores to dry 

somewhat, but not enough to shrink away from the 

tube walls, the cores and core barrels were cut in half 

longitudinally with a metal-cutting band saw. In this 

cutting, the milled slot was held uppermost so that the 

saw cut only the lower wall of the core barrel and 

threw the cuttings downward, away from the core.

» Piggot, C. 8., Apparatus to secure core samples from the ocean bottom: Qeol. 

Soc. America Bull, vol. 47, pp. 675-684,1936.
GEOLOGICAL SURVEY

60° (Follows p. XV) PROFESSIONAL PAPER 196 PLATE 1 10°

20° 10°

Sea level to 

500 meters

500-2,000 

meters

2,000-4,000 

meters

4,000-6,000+ 

meters

BATHYMETRIC CHART OF A PART OF THE NORTH ATLANTIC OCEAN.

The numbered circles indicate the core stations. The dashed line connecting them is the line of the profile shown in figure 1. The light dotted line along the coasts is the 200-meter depth contour. The usual limit of drift ice is shown by the heavy dotted line. The email triangles indicate the position of icebergs reported far beyond their normal range 

during the period January 1900 to July 1916, according to information compiled by J. T. Jenkins (A Textbook of Oceanography, fig. 14, London, Constable & Co., 1921).

U.S. GOVERNMENT PRINTING OFFICE ! 1940—0-228324


GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 2

6 8 9 10 II 12 13

W.

LONGITUDINAL SECTIONS OF THE AIR-DRIED COKES. 

Half of the core barrel was removed from core 11, but the core itself was not cut. Photograph by Geophysical Laboratory, Carnegie Institution of Washington.
GENEEAL INTRODUCTION XV

Each half core then remained undisturbed in its half 

cylinder cradle of brass core barrel. (See pi. 2.)

As several months elapsed between the time the cores 

were opened and the time this investigation began, the 

mud had dried thoroughly when Mr. K. E. Lohman 

took a succession of overlapping photographs of each 

core, about one fifth natural size. These photographs 

were then assembled as a key chart upon which were 

marked the parts from which samples for all phases of 

the investigation were taken. The dried segments of 

mud shifted somewhat from their original places each 

time samples were removed, though care was taken

to see that during sampling the segments kept their 

original order and orientation. By reference to this 

photographic key the findings of all the investigators 

have been correlated.

Most of the material was hard enough to be sawed 

into blocks with a hack saw, but a few of the most 

friable parts were sampled with small channel-shaped 

scoops of sheet metal after the loose material on the 

surface had been brushed away.

Samples for all phases of this investigation were 

taken from only one half of each core, the other half 

being held intact in the Geophysical Laboratory.

GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES 

BETWEEN NEWFOUNDLAND AND IRELAND

PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

By M. N. BEAMLETTE and W. H. BEADLEY

EXAMINATION AND ANALYSIS OF SAMPLES

Before sampling the deep-sea cores from the North 

Atlantic Ocean we made a record of the general aspect 

of the sediments, noting particularly the more obvious 

changes from one kind of sediment to another. These 

descriptive notes served as a guide in selecting the 

samples. As the combined length of the 11 cores is 

nearly 26 meters, a continuous sequence of samples 2 or 

3 centimeters long would have necessitated the study 

of nearly 1,000 samples. With the time available it 

seemed preferable to take fewer samples and give them 

a more thorough examination than could be given so 

large a number. This decision was reached after the 

preliminary examination had shown that layers or 

zones of the mud penetrated were essentially uniform 

for considerable lengths of each core. Accordingly, 

the samples for the lithologic study were taken at intervals that averaged 10 to 12 centimeters, but the interval 

was varied from place to place in order to obtain 

samples representative of the obviously different lithologic types. (See pi. 3.)

Only one half of each core was used for sampling. 

Each sample for lithologic study was 2 or 3 centimeters 

long but included only part of the material, leaving the 

remainder at that place to be sampled for other phases 

of the work. Most of the individual samples represent 

sediment of a fairly uniform lithologic type, but the 

detailed examination showed that a few included sediment of two distinctly different types. Unfortunately, 

the samples sent to the chemical and hydrologic laboratories for determination of total carbonate and for 

mechanical analysis were representative portions of 

whole samples, taken out before the significance of the 

various lithologic units was realized. Therefore, in 

the few samples that include two types of sediment the 

quantity of total carbonate and the mechanical analyses 

are not truly representative of either type. This is 

illustrated most strikingly by sample B-5S-59 from 

core 5. Microscopic examination showed that the 

upper part of this sample was distinctly different in 

composition and texture from the lower part. Had the 

two parts been analyzed separately the data plotted in

228324°—40——2

plate 3 would have shown a clear distinction between 

two lithologic zones rather than features that are 

intermediate between the two.

The samples were first examined under a binocular 

microscope, at which time the film of mud that had 

been smeared down along the walls of the core barrel as 

it penetrated the sediments was removed. In the few 

cores taken in places where the mud through which the 

core barrel passed was sticky, lumps and rolls of the 

sticky mud were carried downward below their normal 

stratigraphic position and squeezed into the core. 

Contamination of this sort, however, was easily recognized, and the contaminating mud was removed. In 

the examination of the samples under the binocular 

microscope the general lithologic type was noted, 

together with any evidence of bedding or other textural 

or structural features, such as borings. This examination also included estimates of the percentage of Foraminifera and of recognizable inorganic constituents, such 

as zones of more abundant volcanic glass shards, pebbles 

and aggregates of tiny spherules of iron sulphide.

A little material scraped from a clean face of the 

sample was immersed in a liquid whose refractive index 

was 1.545, for examination under the petrographic 

microscope, and the relative abundance of the finer 

organic and inorganic constituents was estimated. 

These constituents included the diatoms and other 

siliceous organisms and the minute calcareous algae 

belonging to the Coccolithophoridae. Accurate determination of the amounts of these constituents would 

have required a great deal more time than seemed 

warranted. The relative accuracy of these estimates is 

considered under the heading "Carbonante content of 

the sediments."

The samples were next submitted to the chemical 

laboratory of the Geological Survey, where E. T. 

Erickson determined the approximate content of total 

carbonate in all samples by treating them with hot 

dilute hydrochloric acid until the solution was slightly 

acid as indicated by methyl orange. This procedure, 

though rather crude, was adopted for its speed, so that 

many samples could be tested. The results are subject 

to errors of several percent.

1
GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

In samples taken near the top, middle, and bottom 

of each core Erickson also determined quantitatively 

the MgO, CaO, and MnO in a representative part of 

each sample. The insoluble residues from each of the 

samples were then wet-screened for mechanical analysis 

in the hydrology laboratory of the Geological Survey, 

under the direction of C. S. Howard. Before screening they were shaken in a mechanical agitator for about 

4 hours with a comparatively large volume of distilled 

water, to which had been added a small quantity of 

dilute sodium oxalate solution. Like the carbonate 

determinations, these mechanical analyses are only 

approximations, owing largely to the difficulty of dispersing the sediment that had been treated with acid 

and thoroughly dried.

The screened fractions were then examined microscopically for a closer estimate of the proportions of 

certain noncalcareous constituents, such as volcanic 

ash and siliceous organisms. In this examination the 

rather large percentages of clay aggregates in the sandsize fractions, obviously the result of incomplete disintegration of some of the more clayey samples, were 

also estimated, in order to correct the mechanical 

analyses, the results of which are plotted in plate 3.

This examination revealed the need of supplementary 

data from certain parts of the cores between samples; 

accordingly, additional samples were taken and subjected to the same tests, and the results were also plotted 

in plr.je 3. Much of the material between samples 

was then examined for a few particular features, in 

order to delimit the zones of volcanic glass shards and 

zones of glacial marine deposits and also to make certain that no zones of volcanic material had been missed.

ACKNOWLEDGMENTS

In the preparation of this chapter on the lithology 

and physical geology of the cores we have had the 

benefit of discussion with many of our colleagues in the 

Geological Survey and with various members of the 

Geophysical Laboratory of the Carnegie Institution. 

Acknowledgment is made at appropriate places in the 

text for analyses and tests made for several phases of 

the investigation, and we wish to express here our 

thanks to C. S. Howard, of the hydrology laboratory, 

and R. C. Wells and George Steiger, of the chemical 

laboratory, for their ready cooperation and for the 

laboratory space and facilities which, to their own 

inconvenience, they generously placed at our disposal.

PRESENTATION OF DATA

Many of the data obtained from the investigations 

outlined above are presented graphically in plate 3 to 

facilitate general comparison, although the variations of 

any one constituent are somewhat less easily followed 

in so comprehensive a diagram. The boundary between material of silt size and sand size as used in this

report is 0.074 millimeter, instead of the 0.0625 millimeter commonly accepted as the upper size limit of 

silt, because, of the sieves available, the one having 

openings of 0.074 millimeter was the nearest. Likewise, the boundary between sand size and coarse sand 

size was taken as 0.59 millimeter, rather than the generally accepted 0.5 millimeter, because 0.59 millimeter 

was the nearest sieve size available. The proportion 

of coarse sand in the sand-size fraction of the sample 

seemed significant enough to be indicated on the diagram, but the difficulty of showing effectively small 

percentages necessitated special plotting. Consequently, the percentage of coarse sand in the sand-size 

fraction of each sample is plotted in a separate column 

to the right of the column representing the core. The 

right-hand column shows also samples that contain one 

or more pebbles 3 millimeters or more in mean diameter. 

In view of the apparent significance of these pebbles, it 

is unfortunate that the data are not adequate to show 

their relative abundance. In the course of sampling it 

became evident that only samples from cores of diameter much larger than the ones available could show 

the true quantitative distribution of pebbles as large as 

these, therefore no attempt was made to show in plate 

3 whether the sample contained one or several. Supplementary examination of the whole cores, however, 

indicated that adequate data on their distribution in 

the cores would show more clearly their zones of occurrence hi the sediments. .

The column representing the core samples shows also 

the relative abundance of Foraminifera and of coccoliths, both of which are discussed further in connection 

with the carbonate content of the sediments. (See 

pp. 17-21.) The coccoliths are minute calcareous plates, 

most of which are between 0.002 and 0.015 millimeter in 

diameter. The symbol "common" means that they are 

numerous, though by reason of their small size they 

make up roughly only about 1 percent of the whole 

sample; "abundant" indicates that they make up about 

5 percent or more of the sample. Even where most 

abundant, however, they probably do not make up 

more than 10 percent of the sediment.

The lines between cores shown in plate 3 indicate the 

correlation of zones of distinctive sediment. The 

evidence upon which these zones are distinguished and 

correlated is given below in considerable detail, together 

with interpretations of their significance.

STRATIGRAPHIC UNITS

VOLCANIC ASH ZONES

Shards of volcanic glass are rather abundant hi the 

upper part of most of the cores and are sufficiently 

plentiful to characterize a zone. This upper volcanic 

ash zone is indicated in plate 3 by the uppermost 

stippled zone. The volcanic ash is abundant only in 

the lower part of the zone, and the base of the zone is 

rather sharply delimited. Above the base of the zone
PAET 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

the shards rapidly decrease in abundance upward, 

though they are sparsely scattered through the sediment to the top of each core. The ash consists of 

unaltered vitric shards that have an index of refraction 

near 1.51, which suggests that the glass is of alkalic 

or calc-alkalic composition. The characteristic form 

of the shards makes all but the finest grains recognizable, even under the binocular miscroscope. A reexamination of material from this ash zone, including 

samples intermediate between those represented in 

plate 3, showed that near the base of the upper ash 

zone in most of the cores there are generally several 

thin layers in, which the ash is distinctly more abundant 

or, in some samples, forms the dominant constituent; 

but between these more or less distinct layers shards 

are mixed with a greater proportion of other sediment. 

In cores 7 and 9 the ash is not concentrated in distinct 

layers and the only marked difference is the increase 

in abundance downward to the well-defined base of 

the zone. The apparent significance of this scattered 

distribution of the shards within the zone of volcanic 

ash is considered under the headings "Evidence of 

bottom currents" and "Role of mud-feeding organisms." 

(See pp. 14-15, 22-23.)

Although volcanic ash is the dominant constituent, 

in some of the ill-defined layers one to several millimeters thick, it rarely makes up more than 5 percent 

of the total sediment in an ordinary sample 2 to 3 

centimeters long from the upper ash zone, and it averages nearer 1 percent. In the noncalcareous residues 

of these samples, however, the volcanic ash commonly 

makes up about 25 percent of the sand-size material 

and is therefore a distinguishing feature of this zone. 

In the upper ash zone the volcanic ash is present in 

greatest concentration in core 9, and there also the concentration is greatest in the lower part of the zone. 

Much of the scattered ash in the upper part of the zone 

in this core may represent contributions winnowed 

from the sediment on nearby areas of much shallower 

water. (See p. 14.)

A correlation of this upper ash zone from one core 

to another is suggested in plate 3, and though this 

correlation appears to be somewhat less certain in 

core 8 on the mid-Atlantic ridge and thence eastward, 

other lines of evidence, considered on page 6, seem 

to confirm the interpretation indicated.

Cores 4 to 7, on the west side of the mid-Atlantic 

ridge, penetrated a lower zone of volcanic ash, which 

is similar to the upper one. In the lower zone, the 

vitric shards, as in the upper zone, have a refractive 

index of 1.51 and are scattered through the zone rather 

than occurring in one or more sharply defined layers. 

The lower zone differs from the upper one in commonly 

having smaller shards and fewer of them. Reasons for 

the failure to find this lower ash zone in core 8, and in 

any of the cores east of the mid-Atlantic ridge are considered on page 6, where the correlations are discussed.

An occasional shard of volcanic glass having a refractive index of 1.51 was found in several samples between 

the upper and lower ash zones. Because these stray 

shards are so rare it seems probable that they were 

reworked from the lower ash zone up to their present 

positions by mud-feeding organisms or that they were 

derived from nearby mounds or ridges on the sea floor 

where the lower ash zone is exposed to the action of 

gentle currents. (See pp. 14-15.) The stray shards, however, are most common in samples B-53 and B-55 of 

core 5 and in sample B-214 of core 12. Taken alone, 

the relative abundance of volcanic ash in these samples 

suggests the existence of other ash zones, comparable 

to those just described though thinner and with a lower 

percentage of volcanic material. An unusual significance attaches to these three samples, however, for 

reasons other than their content of volcanic ash. The 

layers that they represent have unusually sharp boundaries at both base and top, they contain relatively 

little of the usual fine-grained constituents, and they 

have other distinctive physical characteristics, all of 

which suggest that they resulted from submarine slumping. These anomalous samples are considered more fully 

under the heading "Submarine slumping" (pp. 15-16).

The similarity of the alkalic glass shards to ash from 

explosive volcanic eruptions and the distribution of the 

shards in the upper and lower ash zones suggest that 

each of these zones represents an accumulation of normal volcanic ash that was transported through the air 

out over- the ocean. No progressive increase in either 

the amount or grain size of the pyroclastic material in 

a particular direction was detected, but original variations of this sort may well have been obscured by the 

local variations believed to be due to redistribution of 

the shards.

The source of the alkalic glass shards in these cores 

is unknown. Geologically recent eruptions in the 

Azores include trachytic as well as ferromagnesian 

materials, and possibly the ash may have come from 

there. Alkalic volcanic rocks are associated with the 

basaltic volcanics of Iceland and Jan Mayen and, 

according to Peacock, 1 some of the volcanic activity in 

Iceland occurred during Pleistocene and post-Pleistocene time. The volcanoes of these northern islands that 

expelled the more silicic material may have been the 

source of the ash that characterizes the zones of volcanic 

ash in the cores.

GLACIAL MARINE DEPOSITS

From a little below the base of the upper volcanic 

ash zone downward for a short distance, most of the 

cores show a decrease in the amount of calcium carbonate and a corresponding decrease in the number of 

both Foraminifera and coccoliths, which are the dominant calcareous organisms. (See pi. 3.) As these limy

1 Peacock, M. A., Geology of ViSey, southwest Iceland: A record of igneous activity in glacial times: Royal Soc. Edinburgh 

Trans., vol. 54, pp. 441-465, 1925-1926.
GEOLOGY AND BIOLOGY OP NORTH ATLANTIC DEEP-SEA CORES

constituents decrease the clastic sediment increases correspondingly and is marked particularly by a greater 

content of coarse sand, granules, and pebbles. The 

granules and pebbles range in diameter from several 

millimeters to more than a centimeter. Most of them 

are somewhat rounded, but some are angular. They 

represent a wide variet}^ of rock types, of which limestone is the most abundant; but various types of darkcolored shale, mudstone, sandstone, and gueissic and 

schistose rocks are also common. Less common are 

granules and pebbles of dolerite, granodioritc, quartzite, 

granulite, chert, and probably other rocks.

The size of these rock grains and the wide range of 

lithologic types that are representative of continental 

rocks rather than rocks of volcanic islands lead us to 

believe that their occurrence in these deep-sea sediments, far from land, means that they were transported 

by drifting ice. The same explanation has been given 

to account for the many pebbles, cobbles, and boulders 

that have been dredged from different parts of the 

North Atlantic. Peach 2 and Flett 3 have given detailed 

descriptions of some of the pebbles and boulders found 

in the dredgings. Some of the larger pebbles and cobbles 

have facets and striated surfaces like the cobbles found 

in glacial moraines. Their transportation to deep parts 

of the ocean remote from land, seems to be reasonably 

explained only by the assumption that they were carried by drifting ice. Cobbles of this sort have been 

dredged from the ocean floor as far south as the Azores 4 

and at stations north of Madeira,5 which suggests that 

they were transported by floating ice during the Pleistocene, when glaciers filled the Irish Sea and extended out 

over large areas of the continental platform into the 

North Atlantic.

The large amount of rock debris that may be transported by drifting icebergs, particularly those from 

glaciers and inland ice, as contrasted with drifting shelf 

ice, is suggested by Tarr's statement,6 "There are 

thousands of tons of boulders, gravel, and clay sent into 

the sea from the front of the Cornell glacier every year, 

and much of this passes beyond the fjord out into 

Baffin Bay." Pratje 7 reported that icebergs from land 

ice in the South Atlantic have been found to carry as 

much as 16 cubic centimeters of sediment per liter of 

ice, or about 1% percent by volume.

2 Peach, B. N., Report on rock specimens dredged by the Michael Sars in 1910, by 

H. M. S. 1 riton in 1882, and by H. M. S. Knight Errant in 1880: Royal Soc. Edinburgh 

Proc., vol. 32, pp. 262-288,1913.

3 Flett, J. S., Report on the rock specimens and some of the oozes collected by the 

S. S. Faraday and S. S. Minia from the bed of the North Atlantic in 1903, in Murray, 

Sir John, and Peake, R. E., On recent contributions to our knowledge of the floor of 

the North Atlantic Ocean: Royal Geog. Soc., Extra Pub., pp. 23-30,1904.

4 Andrge, K., Die Geologie des Meeresbodens, p. 294, Leipzig, 1920. 

«Idem, p. 379.

6 Tarr, R. S., The Arctic sea ice as a geological agent: Am. Jour. Sci., 4th ser., vol. 3, 

p. 228, 1897.

7 Pratje, O., Bericht fiber die geologische Arbeiten der deutschen atlantischen Exp. 

Metsor: Gesell. Erdkunde Berlin Zeitschr., 1926, p. 257.

Philippi's study 8 of the bottom sediments from the 

Antarctic collected by the Gauss, in part by coring and 

in part by dredging, helps greatly to explain analogous 

sediments in the North Atlantic cores. The sediments 

adjacent to the ice front in Antarctica contain little 

calcium carbonate but consist dominantly of clastic 

material, including coarse sand and pebbles of various 

metamorphic and igneous rocks. The fraction of finer 

sediments consists of silt rather than the clayey material that is typical of the common oceanic blue mud. 

These sediments, which Philippi appropriately named 

"glacial marine deposits," apparently extend northward 

only about as far as the northern limit of pack ice. Core 

samples froiri farther north, however, revealed the 

highly significant fact that these glacial marine deposits 

extend northward beneath the diatom ooze that is forming today in a wide belt north of the pack ice. Cores 

from yet farther north contained glacial marine deposits 

below a layer of globigerina ooze, which is the kind of 

sediment accumulating today in that part of the ocean 

north of the area of diatom ooze. The diatom and 

globigerina oozes cover the glacial marine deposits to 

a depth of 10 to 20 centimeters. The glacial marine 

deposits now being formed in the region of pack ice 

led Philippi to believe that the similar deposits farther 

north were deposited during the Pleistocene epoch, when 

the ice front was much farther north. He also suggested 9 that the downward decrease in calcium carbonate, commonly observed in cores of ocean-bottom 

sediments a meter or less in length, even in the equatorial Atlantic, reflects a climatic control and that the 

lesser quantity of calcium carbonate is a consequence 

of the colder water during the Pleistocene.

The zone of sediment underlying the upper ash zone 

in our North Atlantic cores (see pi. 3) is so similar to 

the glacial marine deposits of Philippi that it is interpreted as a glacial marine deposit of the last glacial 

stage of the Pleistocene. This interpretation is confirmed by Cushman and Henbest (see pi. 4), who conclude 

from their study of the foraminiferal faunas that this 

zone is characterized by a pelagic fauna from colder 

water than that of the overlying globigerina ooze. Below 

the glacial marine zone just described we found in 

some of our cores, particularly cores 4 to 7, which were 

taken west of the mid-Atlantic ridge, an alternating 

sequence of glacial marine zones and zones of sediment 

resembling rather closely those forming today in that 

part of the ocean. All these glacial marine zones have the 

distinctive features that have already been described— 

namely, the pebbles, the coarse sand, the relatively

8 Philippi, E., Die Grundproben der deutschen Sudpolar-Expedition, in Von 

Drygalski, E., Deutsche Sudpolar-Expedition 1901-1903, Band 2, Heft 6, pp. 431-434, 

1912.

9 Philippi, E., tiber das Problem der Schichtung und fiber Schichtbildung am 

Boden der heutigen Meere: Deutsche geol. Gesell. Zeitscbr., vol. 60, pp. 346-377, 

1908.
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 186 PLATE 8

Lat. 46°03'00"N.

Long.43°23'00"W.

Depth 4700meters

3

Lat. 48°29'00"N. 

Long.35°54'30"W. 

Depth 3,955 meters

4

Lat. 48°38'00"N.

Long. 36° 01'00" W.

Depth 4820meters

5

Lat 4go 03'30"N. 

Long.32°441 30"W. 

Depth 4,125 meters

6

Lat. 49°32'00"N. 

Long. 29° 21' 00"WDepth 21250 meters

7

FARADAY HILLS 

Lat. 49°36'00BN. 

Long. 28°54'OOW. 

Depth 1,279 meters 

8

Lat. 49°40'00"N. 

Long. 28°29'OOW. 

Depth 3,745 meters

9

Lat. 49°45'00N N.

Long. 230 30'30"W.

Depth 4,190 meters

10

Lat. 48°381 00"N. 

Long. I7°09'00"W. 

Depth 4,820 meters

B-2

B-3

B-4

B-5

W-3B-6 v-a[E

B-7

B-8

B-9

BHO

W-5J

B-12

B-13

B-14

B-15

W-6J

B-16

W-7{B-/8

•'

t

B

i

t

t

B

I

:

1

:

1

I

! HI

II

•mil

Nttl

m\

11

Hill

i

III

II

1

'

•

• ,

. . ':•"••/

• • .-..;;/

' ' "•£/

V;

B-19

228324—10 (Face p. 4)

B-73

B-74

B-75

-B-76

B-102

Lat. 49°37'00"N. 

Long. I3°34'00"W. 

Depth 3,230 meters 

12

Lat. 49WOO"N. 

Long, is-as'ocrw.

Depth 1,955 meters 

13

W-18

Sample taken from the anchor 

flukes at the site of core IO.

Sample taken from the waterexit ports of the coring device.

QIIIIII] Percentage of total carbonate

-i——r--i Percentage of clay and silt 

J——'-J (Iess than 0.074mm.).

Percentage of material of sand size 

or larger (greater than 0.074mm.).

Width of column represents total amount 

of material of sand size in sample. Length 

of bar represents percentage of coarse sand 

(larger than 0.59mm.). Large dot at end 

of bar Indicates presence of one or more 

pebbles 3mm. or more in mean diameter.

Percentage of Fbraminifera (indicated by 

the distance of the dotted line from the 

left side of the column).

Coccoliths abundant.

Coccoliths common.

Both samples are parts of strata 

• that lie stratigraphically higher 

than the top of core 10.

B-227

^^•iii^ Zone of alkalic volcanic glass shards.

Ks'iV-' iiV-i-Jt sl/li'l

Zone of glacial marine deposits.

DIAGRAM SHOWING THE CORRELATION OF THE LITHOLOGIC ZONES IN THE CORES.

Each core is represented by two vertical columns. The patterned rectangular blocks in each left-hand column represent samples that were taken for routine mechanical and 

chemical analyse* and microscopic examination. The parts of the core* from which namf.len were taken for special purposes or supplemental examination are indicate 1 by 

braces. The samples are numbered in two series distinguished by the prefix letters B and W. The width of each column is taken to represent 100 percent by weight of 

the sediment, and the horizontal length of each pattern within a sample block represents the percentage of the constituent. The left-hand column nhows the percentage of 

carbonate, clay and silt, sand, and Foraminifera and the relative abundance of Coccoliths. The right-hand column indicates the percentage of coarse sand and the presence 

of pebble*.
GEOLOGICAL SURVEY

WEST

PROF

DIAGRAM SHOWING PAST FLUCTUATIONS IN THE TEMPERATURE OF THE SURFACE WATER AT THE SITE 

The shaded blocks represent samples taken for the study of the organisms by J. A. Cushman, L. G. Henbest, W. L. Tressler, Austin Clark, and H. A. Rehder. The center line of eac

water temperature. The large dot in each shaded block indicates qualitatively the deviation from the present temperature. The dotted line connecting these points shows the tr

sample to the next. The extremes of temperature in different columns are not necessarily the same though they are comparable. luterpretation by J. A. Cushman and L. G. Hen

PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

small percentage of calcium carbonate, the small 

number of Foraminifera, and the virtual absence of 

coccoliths. They have other features characteristic 

of the glacial marine deposits, such as a smaller quantity 

of clay, which is evident from the texture and the smaller 

shrinkage of the air-dried samples, and, locally at least, 

a lumpy structure, which appears to represent ellipsoidal or tubular borings that were subsequently filled 

with the adjacent mud to form coprolite-like pellets. 

Some of the pellets are as much as a centimeter hi 

diameter. Whether these are coprolites or mud-filled 

borings of molluscs, worms, or some other organism is 

not known, and the significance of their occurrence in 

the glacial marine deposits in greater abundance than 

in other sediments is not apparent.

Schott's recent study 10 of the Foraminifera in the 

cores from the equatorial Atlantic collected by the 

Meteor expedition led to a similar interpretation of 

Pleistocene and post-Pleistocene deposits in that part 

of the ocean. His interpretation was based only on 

the ecology of the Foraminifera, as the sediments of 

that part of the Atlantic showed no accumulations of 

ice-rafted sand and pebbles. The cores, which averaged 

less than a meter hi length, were sampled in the upper, 

middle, and lower parts. They showed a surface layer 

containing a warm-water fauna, a lower layer containing a cold-water fauna, and some of the longest 

cores showed a still lower layer containing a warmwater fauna. In the two layers that indicated a 

warm-water environment the Foraminifera were essentially like those living today in that part of the ocean. 

Schott interpreted the intermediate layer, that layer 

representing a cold-water environment, which in most 

places contained less calcium carbonate, as a deposit 

formed during the latest Pleistocene glacial stage; the 

lowest layer as a deposit of the last interglacial stage; 

and the uppermost layer as a post-Pleistocene deposit.

The correlation of the glacial marine zones and other 

distinctive zones that we found in our North Atlantic 

cores is discussed below, together with an interpretation 

of their significance.

CORRELATION OF ZONES REPRESENTED IN THE CORES

Layers or zones of alkalic volcanic ash hi general are 

reliable for use in correlating strata because this kind of 

ash is erupted from volcanos of the explosive type and is 

distributed widely in the air. It must therefore accumulate on the sea floor at essentially the same time 

throughout the extent of its dispersal. When such ash 

zones are parts of a sequence of distinctive beds and the 

sequence is repeated at the several localities between 

which strata are to be correlated the reliability of the 

ash zones is further enhanced. As indicated in plate 3, 

cores 4, 5, 6, and 7 contain two ash zones and have the

'« Schott, W., DieForaminiferen in dem aquatorialen Teil des Atlantischen Ozeans: 

Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 3, Lief, 

1, pp. 120-130, 1935.

same sequence of glacial marine deposits between the 

ash zones. Below the lower ash zone in each core there 

is another glacial marine zone, which is underlain by 

foraminiferal marl similar to that found today at the 

surface of the ocean floor. The sequence of zones in 

these four cores agrees so well that their correlation 

seems well established in this area west of the midAtlantic ridge.

Core 3 is markedly different, as might be expected 

from its position within the area of terrigenous mud, or 

blue mud, near the Newfoundland Bank. This core 

consists of a remarkably uniform calcareous mud. 

Three thin and rather widely spaced layers of less limy 

mud and one thin silty layer near the bottom mark the 

only departures from the apparent homogeneity of this 

core. Small shards of alkalic volcanic ash like those in 

the ash zones of the other cores are very sparsely disseminated throughout this core but are not concentrated in any zone. The sediment of this core contains 

only an insignificant amount of sand-size clastic grains 

and no zones of coarse sand and pebbles, such as are 

found in the glacial marine zones of the other cores. 

The interpretation by Cushman and Henbest of the 

Foraminifera in this core (see pi. 4) is that the surfacewater temperature was nearly uniform while the sediments represented by the core were accumulating, 

except for the three thin clay zones. The pelagic 

Foraminifera hi the clay zones indicate colder water. 

Despite these thin cold-water zones, the distribution of 

the volcanic ash shards and the absence of sand and 

pebble zones lead us to believe that this core represents 

only sediments of post-Pleistocene time that accumulated in an area where the rate of sedimentation was 

more rapid than at the sites of the other cores. A core 

of greater length from this locality would be of particular interest to check this interpretation and give a basis 

for comparison of the post-Pleistocene rate of accumulation at this station with the rate at other core stations.

Core 3 contains no coarse sand and not even a single 

pebble, a fact that seems at first somewhat surprising, 

because this is the only one of the 11 cores that comes 

from within the present usual limits of drift ice. (See 

pi. 1.) However, the investigations of a number of 

explorers, notably Boggild and Nansen,have shown that 

much of the floor of the Arctic Ocean well within the 

limits of drift ice is covered with a deposit made up 

only of silt and clay that is free from sand and pebbles. 11 

The explanation seems to be that even the berg ice in 

the Arctic and North Atlantic now contains but little 

clastic material, and apparently much of that little is 

dropped between Greenland and North America before 

it reaches the region south and southeast of the Newfoundland Banks. During the glacial epochs, however, the continental glaciers presumably furnished

" Andree, K., Geologic des Meeresbodens, pp. 378-379, 469-475, Berlin, Gebrflder 

Borntraegcr, 1920.
6 GEOLOGY AND BIOLuGY OF NOETH ATLANTIC DEEP-SEA CORES

many more bergs, and these bergs carried much clastic 

debris into the ocean.

Core 8, which was taken in 1,280 meters (700 fathoms) 

of water on the Faraday Hills part of the mid-Atlantic 

ridge, does not show the well-defined sequence of zones 

noted in cores 4 to 7, consequently its correlation with 

them is rather uncertain. The sediments throughout 

this core consist largely of sand and sand-size calcareous 

organisms, and the proportion of fine-grained material 

is so small that the dry core is friable. As is discussed 

later under the heading "Evidence of bottom currents" 

(pp.14-15) the sediment at this place seems to have accumulated where currents moved over the ridge with 

sufficient velocity to winnow out most of the finer constituents. As a result of this selective process the upper 

ash zone in core 8 contains comparatively few shards, 

but these are large and thick. Shards were found as 

far down as the top of sample B-131, which is therefore 

taken as the base of the upper ash zone. Because the 

shards are less numerous and the zone less well defined 

than in other cores, the correlation line at the bottom 

of the upper ash zone is indicated in plate 3 as doubtful. 

Although other lines of evidence make it seem probably 

that core 8 penetrated deep enough to have passed 

through the lower ash zone, no ash was found. Inasmuch as the shards in this lower zone are generally 

finer and less abundant than those in the upper ash 

zone, it is possible that they may all have been winnowed out, as have most of the shards hi the upper 

zone, so that no trace remains at this site. The glacial 

marine zones are likewise less surely identifiable in this 

core, for the reason that the coarser sand and pebbles 

characteristic of the glacial marine deposits are less 

distinctly concentrated at definite horizons, perhaps 

because they have been more reworked and mixed with 

interglacial and postglacial sediments. Correlation of 

the glacial zones in core 8 with those in the other cores 

is therefore unsatisfactory, and this uncertainty is indicated in the correlation lines shown in plate 3.

Core 9 contains an exceptional abundance of volcanic 

ash in the middle part, and shards are scattered rather 

sparsely through it from the middle to the top. The 

distribution of the ash inclines us to believe that this 

ash zone corresponds with the upper ash zone of the 

cores west of the mid-Atlantic ridge. This belief is 

strengthened by the absence of coarse-grained material 

of the glacial marine type, either scattered or in beds, 

within the ash zone, and by the occurrence of a welldefined glacial marine zone a short distance beneath 

the base of the ash. The unusual concentration of 

thin, delicate volcanic glass shards in this core and the 

unusual abundance of other fine-grained constituents 

such as diatoms, coccoliths, and clay-size particles are 

discussed more fully on page 14.

The correlation of core 10 with the others is somewhat unsatisfactory for two reasons—first, the coring 

device penetrated deeper than the length of the core

barrel, so that an unknown amount of sediment was 

lost through the water ports above the top of the core 

barrel; and second, at this station there are two rather 

thick beds of an extraordinary type of mud not represented in any of the other cores. At the time this 

core was taken Piggot collected some of the mud that 

had come out of the top of the core barrel and lodged 

in the water-exit ports. This sample (W-18) was of 

the same peculiar mud that makes up the uppermost 

quarter of the core, but it contained a moderate quantity of small pebbles and coarse sand. Piggot also 

collected, at this same station, a sample (W-17) of the 

globigerina ooze that stuck to the anchor flukes. Thus 

we know that at this station globigerina ooze blankets 

the sea floor, as it does at all the other stations except 

No. 3. Apparently all of the layer of globigerina ooze, 

the thickness of which is unknown, and some of the 

peculiar mud that makes up the top of core 10 was 

lost through the water ports. Nevertheless, it seems 

probable that the volcanic ash zone in this core is the 

upper ash zone of the other cores because of the abundance and general coarseness of the shards; because the 

shards continue upward, though sparsely, to the top 

of the core; because they were found also in the globigerina ooze above; and because there is a relatively 

thick glacial marine zone just below the base of the 

ash. The coarse sand and pebbles in the mud a little 

above the top of this core might be interpreted as 

material dropped from a stray iceberg as are other 

scattered or isolated pebbles found outside the glacial 

marine zones in the other cores. However, as this 

particular sample came from a disturbed core, not too 

much significance can be attached to its peculiarities.

Core 11 struck hard volcanic rock before penetrating 

any of the recognizable zones used in correlating the 

cores. This rock was hard enough to bend the core bit 

and stop it after it had penetrated the sediments for 

only about 34 centimeters. The thin deposit of globigerina ooze overlying the rock contains no shards of 

alkalic glass such as are scattered through the other 

cores, sparingly but continuously, from the base of the 

upper ash zone to the surface of the sea floor. The 

possible significance of this is considered on page 32, 

where the volcanic rock encountered in this core is 

discussed.

Core 12 penetrated the upper volcanic ash zone and 

the usual subjacent zone of glacial marine deposits, 

which at this site is thicker and somewhat less clearly 

defined than in most of the other cores, particularly 

those west of the mid-Atlantic ridge. This lack of 

clear definition may be due to the location of the station 

at which the core was taken, near the base of the continental slope, where material swept from the platform 

above may have diluted the glacial marine deposit. 

The bottom half-meter of this core consists of sediment 

containing an abundance of calcareous organisms 

of types that indicate a warm-water pelagic fauna.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS

(See pi. 4.) It also contains a larger percentage of sand 

and granules than the postglacial deposits at the top of 

the core. The larger grain size and the presence in 

abundance of pteropods and ostracodes suggest that 

the material in the lower part of this core may have 

accumulated in water shallower than now exists at 

this place, namely 3,230 meters (1,770 fathoms). 

According to Murray and Hjort, 12 2,740 meters (1,500 

fathoms) is about the extreme lower limit for pteropod 

shells, and ooze characterized by pteropods is rarely 

found in water deeper than about 1,825 meters (1,000 

fathoms). It should be borne in mind, however, that 

the depth at which pteropod shells dissolve is dependent 

upon the saturation of the water with respect to calcium 

carbonate and that in the geologic past the ocean water 

may at one time have been saturated with calcium 

carbonate to a depth considerably greater than it is 

today and at another1 time less. The number of ostracodes in the lower part of core 12 is rather unusual. 

According to Tressler (chapter on " Ostracoda"), these 

organisms are more plentiful in the cores from less 

depth, particularly core 8, from 1,280 meters, and core 

13, from 1,955 meters.

As the pteropod-bearing sediment in water deeper 

than would be expected is in the general vicinity of 

core stations 10 and 11, where volcanic rock was found, 

the suggestion is offered that foundering of the ocean 

floor may have occurred contemporaneously with the 

volcanic activity. Additional cores might provide 

interesting data bearing on the possibility that this 

part of the North Atlantic represents a foundered part 

of the Arctic or Thulean basaltic province, 13 which 

includes part of northwestern Scotland, northern Ireland, Iceland, Jan Mayen, and southeastern Greenland. Another possibility is that at the time this pteropod sediment was accumulating the water was saturated 

with calcium carbonate to greater depth than it is today 

and for that reason the pteropod shells were not dissolved. A third suggestion, that the sediment containing the pteropods, ostracodes, and sand may have 

slumped from its original position higher on the continental slope, is discussed more fully on pages 15-16.

Core 13 resembles core 8 in having throughout an 

abundance of sand, pebbles, sand-size Foraminifera, 

and rusty stain. As in core 8, nearly every part of 

core 13 is friable, owing to the relatively small quantity 

of fine-grained constituents. The position of this core 

near the edge of the continental platform suggests a 

further analogy with core 8, namely, that it owes its 

textural characteristics and the general indistinctness of 

the ash and glacial marine zones to the combined action 

of bottom currents and the activity of bottom-dwelling 

organisms.

12 Murray, J., and Hjort, J., The depths of the ocean, p. 173, London, Macmillan 

Co., 1912.

13 Tyrrell, G. W.r The principles of petrology, p. 144, London, Methuen & Co., 1926.

The correlation of strata in the cores is thus less satisfactory from core 8 eastward than it is west of the midAtlantic ridge, but the consistent relation between an 

upper ash zone and the uppermost glacial marine zone 

appears to be a reliable basis for tying together all the 

cores except 3 and 11. The number and correlation of 

the glacial marine zones east of the mid-Atlantic ridge 

and on the ridge are somewhat dubious.

INTERPRETATION OF THE GLACIAL MARINE 

SUCCESSION

More than ordinary interest attaches to the interpretation of the zones of glacial marine sediments 

revealed by these cores because they may ultimately be 

correlated with events on land during the Pleistocene 

epoch and because cores of ocean-bottom sediments 

open a new approach to the study of glacial epochs. 

Nevertheless, before considering the various possible 

interpretations it may be helpful to attempt to visualize 

the conditions in the North Atlantic that gave rise 

not only to the zones of glacial marine sediment but also 

to sediment of the kind that lies between those zones.

SOURCES OF DETRITUS

The gravel, sand, and terrigenous silt found in the 

glacial marine zones must have been derived chiefly 

from bergs of glacial ice crowded from the land out into 

the sea by the continual growth of the glaciers behind. 

The sea ice, or pack ice, can contain no terrigenous 

debris, other than wind-blown material, except what 

it picks up by freezing to the bottom in shallow water 

or receives from the outwash of flooding rivers. 14 Thus, 

the presence of extensive layers of glacial marine deposits in the part of the North Atlantic from which 

these cores were taken makes it necessary to assume 

that the sea south of the fiftieth parallel of latitude 

contained much berg ice from continental glaciers and 

probably also much shore ice. While the sea level was 

low, during the glacial stages, extensive shoal-water 

platforms probably furnished large volumes of detritus 

to grounded sea ice, as described by Sverdrup 15 for the 

north coast of Siberia. Detritus from this source may 

have contributed as much as bergs. From further 

comparison with conditions as they now exist in both

14 Boggild, 0. B., On the bottom deposits of the north polar sea: The Norwegian 

North Polar Expedition 1893-1896, Scientific results, vol. 5, pp. 50-51, 1906. Trask, 

P. D., The sediments: The Marion Expedition to Davis Strait and Baffin Bay, 1928, 

U. S. Treas. Dept. Coast Guard Bull. 19. pt. 1, pp. 73-74, 1932. Fuchs, V. E., and 

Whittard, W. F., The east Greenland pack-ice and the significance of its derived 

shells: Geog. Jour., vol. 76, pp. 419-425,1930. Stetson, H. C., The bottom deposits, in 

Scientific results of the Nautilus expedition, 1931, pt. 5: Massachusetts Inst. Technology and Woods Hole Oceanogr. Inst., Papers in Physical Oceanography and 

Meteorology, vol. 2, No. 3, pt. 5, pp. 32-35,1933. Sverdrup, H. U., Notes on erosion 

by drifting snow and transport of solid material by sea ice: Am. Jour. Sci., 5th ser., 

vol. 35, pp. 372-373, 1938.

is Idem., pp. 372-373.
8 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

polar seas, we may infer that the drift ice 16 did not 

form a close pack or unbroken sheet over the site of the 

cores but instead was broken and probably was melting rather actively, for the zones of glacial marine sedi-. 

ment contain also some pelagic Foraminifera and 

diatoms that must have lived in the open water. 

Pelagic Foraminifera and diatoms are rare or absent 

from the bottom deposits beneath the continuous sheets 

of pack-ice in both the Arctic and Antarctic. 17

TEMPERATURE OF THE OCEAN, AS 

DEPOSITS

INDICATED BY THE

Rapid melting of the drift ice at essentially its 

southern limit in this part of the North Atlantic may 

well have been due to the warm North Atlantic current, 18 which probably flowed there much as it does 

today, though with somewhat less volume and lower 

temperature during the glacial maxima of the Pleistocene. 19 Many of the warm-water Foraminifera and 

Coccolithophoridae brought in by the current, however, 

are killed off when they reach the cold polar water.20

The convergence of a warm current from the south

16 The term drift ice is used essentially as Priestly defined it (Wright, C. S., and 

Priestly, R. E., Glaciology: British (Terra Nova) Antarctic Expedition, pp. 393-394, 

London, 1922), that is floating ice where the pieces of ice are separated by open water 

whose area exceeds that of the ice. The ice is derived from any source whatever. It 

is equivalent to "open pack ice" and to the German "Treibeis."

17 Nansen, F., The oceanography of the North Polar Basin: The Norwegian north 

polar expedition 1893-1896, Scientific results, vol. 3, pp. 422-427, 1902. Philippi, E., 

Die Grundproben, in Von Drygalski, E., Deutsche Sildpolar-Expedition 1901-1903, 

Band 2, Heft 6, pp. 433-434,1912. Stetson, H. C., Op. cit., pp. 32-35.

18 The northeastward extension of the Gulf Stream according to Iselin's nomenclature. Iselin, C. O., A study of the circulation of the western North Atlantic: Massachusetts Inst. Technology and Woods Hole Oceanogr. Inst., Papers in Physical 

Oceanography and Meteorology, vol. 4, No. 4, pp. 73-75,1936.

19 Brooks, C. E. P., Climate through the ages, pp. 89-90, New York, R. V. Coleman, 1926.

20 Nansen, F., op. cit., pp. 422-427. Hendey, N. I., The plankton diatoms of the 

southern seas: Discovery Repts., vol. 16, pp. 156-159,1937.

Meters 

Oi

upon the melt water of an ice-filled sea and the tendency 

of the warm current to drift northward create a condition that readily accounts for a rather abrupt transition 

between the glacial marine zones and the overlying and 

underlying foraminiferal marl 21 with its warm-water 

fauna. As the areas of drift ice expand southward, 

glacial marine deposits accumulate where earlier the 

remains of warm-water pelagic organisms had been 

accumulating. So also, as the southern limit of the drift 

ice retreats northward, the warm current follows it 

northward, showering the top of the glacial marine 

layer with warmer-water Foraminifera and coccoliths. 

From this concept it follows that the zone of sediment 

between the uppermost pair of glacial marine zones in 

cores 4 to 8, which has a cold-water foraminiferal fauna 

and a texture intermediate between that of the glacial 

marine zones and the zones of foraminiferal marl, 

represents an interval when the southern limit of 

abundant drift ice had not receded much farther north 

than the line of core stations, or perhaps had shifted 

back and forth across that line. The forminiferal mud 

in the other parts of these cores, however, with its 

fauna of the type that lived in surface water, nearly 

but not quite so warm as that of today, indicates stages 

during which the drift ice had retreated nearly as far 

north as it is today.

The succession of events that led to the deposition 

of glacial marine and other sediments in alternating 

sequence may be illustrated somewhat as Lide*n 22 

illustrated a sequence of Pleistocene events in northern 

Europe. (See fig. 2.)

81 Definitions of the terms foraminiferal marl and globigerina ooze as used in this 

report are given on p. 17.

w Liden, Ragnar, Geokronologiska studier ofver det Finiglaciala skedet: Sveriges 

Geol. Undersokning, ser. Ca., No. 9, pi. 7,1913.

facial marine^ deposits

Foraminiferal " marl

Equivalent cold water 

sediments; in part 

red clay and in part 

foraminiferal marl

FIGURE 2.—Diagram showing the distribution of glacial marine deposits and foraminiferal marl in core 7 and the inferred distribution of these two types of deposit in a 

meridional section running through the site of this core. The maximum southward extension of the glacial marine deposits and the northward extension of the foraminiferal marl are unknown and are therefore purely hypothetical. The inference that other glacial marine deposits may underlie the bottom of core 7 is likewise 

hypothetical and is based only upon the physical characteristics of the bottom of core 7 and the absence of any suggestion of pre-Pleistocene Foraminifera. Core 7 was 

chosen for this diagram because it represents the longest period of time of any of these cores.
PAKT 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 9

If traced northward from the latitude of the cores, 

the top of the uppermost glacial marine deposits should 

rise in relation to the surface of the sea floor until in 

the region of perennial pack ice, it or its Arctic equivalent, should form the surface deposit, the wedge of 

foraminiferal marl having thinned out and disappeared 

somewhere south of the region of drift ice. This is suggested by the deposits now forming in the western part 

of Davis Strait in latitude 60° to 65° N., which are derived 

chiefly from the ice brought there by the Labrador current,23 whereas, according to Murray and Hjort,24 foraminifera! marl carpets the sea floor a little farther southeast between Greenland and Labrador. If traced southward from the latitude of the cores, the uppermost glacial marine deposits should wedge out or grade into a 

southern equivalent—perhaps red clay or foraminiferal 

marl.

Data obtained by Schott in his recent work 25 on the 

Foraminifera from the cores taken on the Meteor expedition suggest that the uppermost glacial marine zone 

of the Piggot cores may be represented in the equatorial 

Atlantic by a zone of sediment containing Foraminifera 

that indicate surface water cooler than that now found 

in the same locality. Schott interprets this zone as 

probably the equivalent of the last glacial maximum in 

higher and lower latitudes. In parts of the equatorial 

Atlantic he found also that the upper boundary of the 

cool-water zone coincided approximately with the top 

of a zone of red clay of unknown thickness. The top 

of this zone, which lacks the tropical pelagic Foraminifera, ranges in depth below the surface of the sea 

floor from 10.5 to 66 centimeters. In our cores from 

the North Atlantic, except 3, 9, 10, and 11, the top of 

the uppermost glacial marine zone ranges in depth 

below the sea floor from a little less than 20 to a little 

more than 60 centimeters. In cores 3, 9, and 10 it 

ranges from more than 1 meter to 3 meters or more 

(core 3). The zone in the equatorial region that contains relatively cool-water Foraminifera is underlain in 

some places by globigerina ooze containing the same 

tropical forms that are now accumulating there. The 

cool-water zone averages a little more than 22 centimeters in thickness.

The probability that this cool-water zone in the 

equatorial Atlantic may be the equivalent of the uppermost glacial marine deposit of the North Atlantic cores 

is strengthened somewhat by Philippi's description

83 Trask, P. D., The sediments: The Marion Expedition to Davis Strait and Baffin 

Bay, 1928, TJ. S. Treas. Dept. Coast Guard Bull. 19, pt. 1, pp. 70-78,1932.

14 Murray, J. and Hjort, J., The depths of the ocean, map 4r London, Macmillan & 

Co., 1912.

a« Schott, W-, Die jiingste Vergangenheit des Squatorialen Atlantischen Ozeans 

auf Grund von Untersuchungen an Bodenproben der Meteor-Expedition: Naturf. 

Gesell. Rostock. Sitzungsber. Abh., ser. 3, Band 4, pp. 48-57, 1933. Schott, W., 

Die Foraminiferen in dem Squatorialen Teil des Atlantischen Ozeans: Wiss. Ergeb. 

Deutschen Atlantischen Exped. Meteor, 1926-27, Band 3, Teil 3, Lief. 1, pp. 120-128, 

1935.

and interpretation of the cores taken by the Gauss in 

the South Atlantic and southern Indian Ocean.26 

Philippi pointed out the absence of tropical Foraminifera in a layer of ooze below that now forming and 

noted that the lower boundary of the zone of tropical 

Foraminifera coincided with the top of red clay deposits 

in several parts of the South Atlantic and Indian Oceans. 

He interpreted both the absence of the tropical Foraminifera and the presence of red clay below a blanket of 

globigerina ooze as indicating generally colder water 

throughout the ocean and suggested that the deposits 

formed at that time probably represented the last glacial stage. Red clay was deposited in many parts of the 

ocean at depths where now foraminiferal marl is 

accumulating and in places where only the more; delicate 

shells are being dissolved. It seems reasonable to 

conclude, as he did, that the greater extent of areas 

in which red clay was deposited in the past was due to 

the solvent and oxidizing effect of the greater quantities 

of carbon dioxide and oxygen that the cold water of 

that epoch could hold. As has already been noted, 

Philippi found in cores of bottom sediments from the 

southern Indian Ocean at approximately latitude 45° 

S., globigerina ooze overlying glacial marine deposits, 

and in cores from latitude 50° S. southward to the ice 

front, diatom ooze overlying glacial marine deposits. 

An epoch when all the oceans were colder than they 

are today seems to be implied by the fact that three 

types of cool-water or cold-water deposits formerly 

had a greater areal extent than they do today and 

are, therefore, locally buried beneath a comparable 

thickness of foraminiferal ooze or limy blue mud such 

as that now forming in various parts of the ocean. The 

old glacial marine deposits extended much farther 

from the poles, in both northern and southern hemispheres, than the glacial marine deposits now forming; 

the areas of red-clay deposition were much larger; 

and the sediments characterized by a colder-water 

foraminiferal fauna extended even into the equatorial 

regions. Some very general cause seems necessary 

«to explain these three types of colder-water deposits, 

all buried beneath a comparable thickness of warmerwater deposits. The conclusion seems logical that 

they are all essentially contemporaneous and represent the last glacial maximum of the Pleistocene. 

How much of the Pleistocene may be represented by 

these and other deeper-lying cold-water deposits 

penetrated by the cores is quite another question, 

which leads us back to further consideration, of cores 

4 to 7, from the western part of the North Atlantic. 

Each of which shows four more or less distinct zones of 

glacial marine deposits.

** Philippi, E., Die Grundproben, in Von Drygalski, E., Deutsche SiidpolarExpedition 1901-1903, Band 2, Heft 6, pp. 591-595,1912.
10 GEOLOGY AND BIOLOGY OP NORTH ATLANTIC DEEP-SEA CORES

INTERPRETATION OF THE GLACIAL MARINE ZONES IN 

TERMS OF STAGES OR SUBSTAGES OF THE PLEISTOCENE

Three possible interpretations have been considered: 

First, that each glacial marine zone represents a separate glacial stage of the Pleistocene epoch; second, that 

the two upper glacial marine zones, which are less distinctly separated, represent a bipartite last-glacial 

(Wisconsin) stage, whereas each of the two lower glacial 

marine zones represents a pre-Wisconsin glacial stage; 

and third, that all four glacial marine zones represent 

only substages of advance and retreat within the Wisconsin stage. (See fig. 3, A, B, C.)

foraminiferal marl, leads us to believe that, in the interval between these two uppermost glacial marine zones, 

the southern limit of drift ice repeatedly migrated back 

and forth across the site of these cores. The uppermost 

two glacial marine zones seem to be too closely connected by deposits that represent conditions that were 

almost glacial for us to regard them as separate glacial 

stages of the Pleistocene. They seem rather to represent greater southward extensions of ice in the sea at 

the beginning and end of a single glacial episode.

According to the second interpretation, which postulates for the upper zones a single glacial stage marked 

by a moderate retreat of the ice between two greater

Y7,

CL2

222

Foraminiferal mart comparable to 

that now forming at core station 7

Sediment intermediate in texture and 

composition between glacial marine 

deposits and foraminiferal marl

FIGURE 3.—Diagram showing three possible interpretations, A, B, and C, of the glacial marine zones in core 7, in terms of stages or substages of the Pleistocene, 

o signifies the latest, or Wisconsin stage; 6, c, and d signify earlier, separate glaciil stages of the Pleistocene. 01, 0,3, 0.3, and 04 signify glacial substages of the Wisconsin 

stage. Core 7 was chosen for this diagram because it represents the longest period of time of any of the cores.

extensions, the upper two glacial marine zones would 

correspond to the early and late substages of the Wisconsin.28 (See fig. 3, B.) The lower two glacial marine 

zones in cores 4 to 7 might represent pre-Wisconsin 

stages, as they are separated from each other and from 

the upper glacial marine zones by foraminiferal marl, 

which contains pelagic Foraminifera that indicate surface water nearly or quite as warm as exists there today—in short, foraminiferal marl approaching the type 

now forming in that part of the North Atlantic. (See 

pp. 17-18.) The zones or layers of foraminiferal marl 

in the lower parts of cores 4 to 7 have approximately 

the same average thickness as the layer of postglacial

The hypothesis that each of the four glacial marine 

zones represents a separate glacial stage of the Pleistocene (see fig. 3, A) now seems to us least probable, 

although this was the opinion we held earlier in the 

investigation.27 Cushman and Henbest found, however, that the Foraminifera in the zone between the 

uppermost two glacial marine zones indicate, in general, 

water quite as cold as do those in the glacial marine 

deposits. (See pi. 4.) This, together with the texture 

and composition of the sediment in this zone, which is 

intermediate between glacial marine deposits and

« Bradley, W. H., Bramlette, M. N., and others, Preliminary report on the North 

Atlantic deep-sea cores taken by the Geophysical Laboratory, Carnegie Institution: 

Am. Geophysical Union Trans., pp. 224-226, 1937; The Geological Survey's work 

on the Piggot North Atlantic deep-sea cores: Am. Philos. Soc. Proc., vol. 79, pp. 

41-46, 1938

28 Chamberlain, T. C., and Salisbury, R. D., Geology, vol. 3, pp. 392-394, New 

York, Henry Holt & Co., 1906.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 11

foraminiferal marl at the tops of these same cores (see 

pi. 3), and it is assumed that they accumulated at 

approximately the same rate. This suggests that the 

intervals of time separating the two lower glacial marine 

zones from one another and from the next higher 

glacial marine zone were about equal in length to postglacial time and that during each interval the southern 

limit of the pack and berg ice in the sea retreated 

markedly, though probably not quite so far north as it 

now is. This hypothesis, if true, suggests that each of 

the lower two glacial marine zones represents a distinct 

glacial stage of the Pleistocene, but that each stage was 

set off by interglacial stages of no greater length than 

postglacial time. At the bottom of core 7 the number 

of Foraminifera and coccoliths and the quantity of calcium carbonate decrease markedly. In these same samples the percentage of sand increases conspicuously. 

Both these changes suggest proximity to the top of 

another glacial marine zone, yet the Foraminifera indicate that surface-water temperatures were quite as high 

as when the globigerina ooze just above was forming— 

that is, temperatures much like those that prevail today 

in that part of the North Atlantic. (See pi. 4.)

This second possible interpretation of the glacial 

marine zones seems to imply too short a time for the 

whole Pleistocene epoch, for each of the upper two 

interglacial zones indicates an interval of time about 

equal to postglacial time, whereas, the interglacial 

stage indicated hi the lowest part of core 7 is evidently 

much longer, than any of those above it, and may be 

even longer than this core seems to indicate. Moreover, the length of time represented by the glacial 

marine deposits must be considered. At present we 

have no means of estimating this, but the time represented by the glacial marine deposits might conceivably 

be much longer than that represented by the thicker 

foraminiferal marls between them.

The third possible interpretation is that all four 

glacial marine zones represent only substages of the 

Wisconsin stage (see fig. 3, C), though the latest two 

substages are not separated by a clearly defined nonglacial substage. For the greater part of the Wisconsin 

stage this interpretation apparently implies a greater 

latitudinal range of glacial phenomena both in the 

North Atlantic Ocean and in eastern North America 

than is evident in the record of continental glaciation. 

It implies that for periods of time measured in thousands of years the North Atlantic at approximately 

latitude 50° N. alternately contained an abundance of 

drift ice and then again for thousands of years was 

nearly or quite free of ice. This seems to indicate that, 

except in the intervals between the latest two glacial 

marine zones, the continental ice sheet not only withdrew from the coast but probably retreated well back 

toward its centers of dispersal so that the marine climate 

of the western North Atlantic was not greatly different 

from what it now is. Two observations on the deposits

that lie between the glacial marine zones support this 

inference—the deposits contain Foraminifera and coccoliths that indicate surface-water temperatures about 

like those now prevailing, and they contain virtually 

no ice-borne material.

In the interval between the latest two substages, the 

drift ice in that part of the North Atlantic must have 

been only a little less plentiful than at the times of 

maxima, but the other glacial substages are set off from 

one another by intervals during which the surfacewater temperature along the line of cores was nearly 

as warm as it is today. According to the third hypothesis, the thick unit of globigerina ooze in the lower 

part of core 7 may represent all or part of the interglacial stage that preceded the Wisconsin. Its foraminiferal fauna, which indicates surface water as warm, or 

perhaps warmer, than now prevails at that locality, is 

in accord with this inference.

Although the evidence available is insufficient to determine which of these interpretations of the glacial 

marine succession is the more nearly correct, we are 

inclined to favor the third interpretation—that, all four 

glacial marine zones are substages of the "Wisconsin 

stage. Only more and longer cores can provide adequate data for a completely satisfactory answer.

The speculation may serve a useful purpose in bringing to the attention of those interested not only the 

possible interpretations but also the factors involved. 

To pursue it further at this time seems fruitless. We 

do not know enough about the extent of the sea ice 

and its movements in the North Atlantic during the 

Pleistocene to correlate its advances and retreats with 

those recognized in the continental ice sheet and 

therefrom to give a valid interpretation of the glacial 

marine succession. These few cores do not give enough 

information on the areal extent and number of glacial 

marine zones to reveal their full significance. A series 

of similar but longer cores taken along a line running 

in a general southeast direction from Davls Strait 

through the vicinity of core stations 4 and 5 and on 

southward past the southern limit of the glacial marine 

deposits, would perhaps shed light on phases of the 

glacial epoch not decipherable on land. Such a marine 

record has the advantage of being continuous, and the 

mechanism that operated to bring about recognizable 

changes hi the marine sediments probably was far 

more sensitive to climatic changes than a continental 

ice sheet. This sensitivity is suggested by Philippi's 

observations 29 in the south polar region. He observed 

there that lime-poor glacial marine deposits now forming within the limit of the pack ice are underlain at 

shallow depth by a thin layer of a more limy foraminiferal marl, which in turn overlies glacial, marine 

deposits that contain almost no lime. This thin layer

29 philippi, E., Andeutungen von postglazialen Klimaschwankungen in der Siidpolar-Region, in Die VerSnderungen des Klimas: Eleventh Internat. Geol. Cong. 

Stockholm Ber., pp. 457-459,1910.
12 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

of limy ooze he interpreted as the reflection of a brief 

postglacial amelioration of climate, during which the 

front of the pack ice was considerably farther south 

than it now is. Brooks 3° suggests that this warmer 

epoch which Philippi postulates may be the "climatic 

optimum."

It may be that-the glacial marine history, when fully 

worked out, will provide the best means of testing 

Milankovitch's hypothesis 31 that the several glacial 

and interglacial stages of the Pleistocene were a function 

of solar radiation. Surely the expansion and contraction of areas in the sea that contain much drift ice 

would be more directly and immediately affected by 

changes in the sun's heat than would the advance and 

retreat of thick continental ice sheets. The relation 

between the drift ice and the glacial marine record is 

simple and direct, whereas the relation between the 

advance and retreat of continental ice sheets is indirect

" 3OO 275 25O 225 2OO 175 ISO 125 IOO 75 SO 25 O

THOUSANDS OF YEARS I8OOA.D

FIGURE 4.—Curve showing amplitudes of solar radiation changes at latitude 65° N. 

during the warm half of each year for the past 300,000 years. The variations in the 

amount of heat emitted are expressed in terms of an imaginary shift of geographic 

latitude. Time is reckoned from 1800 A. D. (After Milankovitch.)

and complicated. Yet, despite this apparent directness 

in the linkage between the sun's radiation and the glacial 

marine record, the expansion and contraction of driftice areas in the sea are influenced by other factors, some 

of whose effects, taken singly or in combination, may 

exceed those of solar radiation or be out of phase with 

the solar radiation. One of these factors, analyzed 

by Brooks,32 is that there is a critical polar temperature 

below which a polar ice cap forms and expands rapidly 

to a maximum size. The great cooling effect of floating 

ice accounts for the rapid growth of ice caps and their 

stability.

Milankovitch, according to Zeuner,33 calculated the 

variations in the solar radiation, which depend upon 

three periodical alterations of certain elements of the 

earth's orbit, as follows: (1) the eccentricity of the 

earth's orbit, with a period of 92,000 years, (2) the 

obliquity of the ecliptic, with a period of 40,000 years, 

and (3) the heliocentric longitude of the perihelion, 

with a period of 21,000 years. Milankovitch's 34 curve 

based on these calculations of solar radiation for the

30 Brooks, C. E. P., Climate through the ages, pp. 411-412, New York, R. V. Coleman, 1926.

31 Milankovitch, M., Thgorie mathfimatique des phfinomenes thermiques produits 

par la radiation solaire: Acad. Yougloslave Sci. Arts de Zagreb., pp. 246-291, Paris, 

1920.

32 Brooks, O. E. P., Climate through the ages, pp. 32-45, New York, R. V. Coleman, 

1926.

33 Zeuner, F. E., The Pleistocene chronology of central Europe: Geol. Mag., vol. 72, 

p. 361,1935.

34 Milankovitch, M., Mathematische Klimalehre und astronomische Theorie der 

Klimaschwankungen, Handbuch der Klimatologie. Band 1, Teil A, p. 141, Berlin, 

Gcbriider Borntraeger, 1936.

summer months is reproduced here as figure 4. The 

three radiation minima at 23,000, 72,000, and 115,000 

years are regarded by Milankovitch, Zeuner,35 and 

Blanc 36 as correlative with the three stages of the 

Wtirm glacial epoch in Europe.

Milankovitch's solar radiation curve, taken alone, 

does not seem to indicate four cold epochs corresponding 

to the four glacial marine zones which we think may be 

substages of the latest, or Wisconsin, glacial stage. 

No attempt, however, will be made here to explain 

thi's, or to relate the curve to the glacial marine record, 

because the glacial marine record is clearly fragmentary 

and the relationship is probably more complex than has 

been assumed by Milankovitch, Zeuner, and others.

POSTGLACIAL CLIMATIC CHANGES

Certain minor features of these cores may perhaps 

be explained by changes of climate that had either local 

or regional effects during the postglacial interval. In 

core 3, which we believe consists wholly of post-glacial 

sediment, there are three rather well-defined but thin 

layers that contain more clay, less calcium carbonate, 

and fewer Foraminifera and coccoliths than the rest of 

the core. These are indicated in plate 3 by sample 

numbers B-6, B-12, and B-18. They are also discernible in the photograph of the cores, plate 2. The 

physical character, together with the low surface-water 

temperature indicated by the Foraminifera in the upper 

two, suggests that these clay layers represent comparatively brief, cold episodes when sea ice containing 

no land-derived coarse detritus covered tha't part of the 

sea continuously; on the other hand, the Foraminifera 

in the third clay layer (at the bottom of the core) do 

not suggest surface-water temperatures lower than 

exist there today and thereby weaken the argument for 

this explanation. The sharp lower boundaries of at 

least the upper two clay layers (the base of the other 

clay layer was not penetrated by the core barrel) suggest 

that they may represent slumped material from the 

steep slopes of the adjacent Newfoundland banks. 

For further discussion of submarine slumping see pages 

15-16.

The only other suggestions of postglacial climatic 

changes are the surface-water temperatures inferred 

from the pelagic Foraminifera by Cushman and Henbest. 

(See pi. 4.) The Formanifera in cores 3, 6, 9, and 12 

(as shown in plate 4) indicate that during roughly the 

middle part of the postglacial interval the surface-water 

temperature in those areas in the North Atlantic was 

somewhat higher than prevails there today. This 

change is probably shown best in these particular cores 

because in them the zone of postglacial deposits is 

considerably thicker than in the other cores, where the 

postglacial record is compressed into much smaller 

compass.

» Op. cit., pp. 362-372.

36 Blanc, A. C., Low levels of the Mediterranean Sea during the Pleistocene glaciation: Geol. Soc. London. Quar. Jour., vol. 93, pp. 643-646, 1937.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 13

A change to lower surface-water temperatures is 

indicated by the Foraminifera a little below the middle 

of core 9 (samples B-165 and 166, pi. 3). This change 

to colder conditions occurs at and a little below the base 

of the upper volcanic ash layer. It appears to have 

been a rather brief episode. Such brief episodes could 

not be revealed in the much more condensed sedimentary record of the other cores except by a larger 

number of thinner samples. Judging by the sparsity of 

ash in the lower part of core 3 this core did not reach 

the horizon represented by the cold zone in core 9. 

This temperature change shown in core 9 may, however, 

reflect only a local change in the fauna owing perhaps 

to some temporary change of currents.

RATE OF DEEP-SEA SEDIMENTATION

In order to estimate the rate of sedimentation as 

indicated by these cores it is necessary to make certain 

assumptions about the horizon in this oceanic stratigraphic sequence that corresponds most reasonably 

with a certain phase of the last glacial stage in North 

America. Only one horizon seems to us likely to have 

real meaning in this correlation, and this is the top of 

the uppermost glacial marine zone. This horizon is 

assumed to represent the beginning of the postglacial 

epoch as defined by Antevs, who says:

The postglacial epoch is considered as having commenced 

when the temperature in the southern parts of the previously 

glaciated area had risen to equal that of the present time. In 

eastern North America the ice sheet was then probably confined 

to Labrador Peninsula. This was probably, in round figures, 

9,000 years ago.37

The age of the horizon in the cores that we have 

adopted is, of course, subject to considerable error, 

because we do not know the rate at which the southern 

limit of the drift ice retreated. The drift ice, which 

contains the detritus-laden berg and shore ice, is much 

thinner than the ice of a continental glacier and has 

more surface exposed, so it would surely break up and 

disappear more quickly than the continental ice sheet, 

particularly in the North Atlantic, where the comparatively warm North Atlantic current tends continually to spread northward. Just as foraminiferal 

marl is now accumulating on the sea floor in latitudes 

farther north than the southern part of the Greenland 

ice sheet, so in the early waning phases of the last glacial 

stage the sea probably cleared of ice at latitudes farther 

north than that of the retreating front of the continental 

ice sheet.

Accordingly, the age of the top of the uppermost 

glacial marine zone in these cores is probably greater 

than 9,000 years; but, if we assume for the moment that 

it is 9,000 years, we can estimate the maximum rate of 

deposition for the postglacial deposits. The average 

thickness of the postglacial sediment in cores 4 to 7 is 34 

centimeters. If this was deposited in 9,000 years, the

37 Antevs, Ernst, Late glacial correlations and ice recession in Manitoba: Canada 

Geol. Survey Mem. 168, p. 6,1931.

rate of accumulation would have been about 265 years 

per centimeter. As pointed out above, however, 9,000 

years is probably too short for the time elapsed since 

foraminiferal marl began to form at the sites of these 

cores after the last glacial marine deposits were laid 

down. The rate of accumulation of the forarniniferal 

marl near the tops of these cores may be nearer 1 

centimeter in 500 years than 265, but a closer estimate 

based on these cores is hardly warranted.

A comparison of the thickness of the postglacial sediment in different cores shown graphically in plate 3 

makes it plain that the rate of accumulation differs considerably from place to place even in the ocean abyss. 

The differences depend upon local conditions, as is 

illustrated by core 8, where currents have removed much 

of the normal fine sediment, with the result that the 

building up of the sea floor there has progressed at a 

comparatively slow rate. At the site of core 9, not far 

away, currents and perhaps other factors have caused 

an abnormally rapid rate of accumulation. The blue 

mud in core 3 evidently accumulated at least 10 times 

faster than the postglacial sediment in core 4.

Schott,38 in his study of the stratification indicated by 

the Foraminifera in the cores taken by the Meteor in 

the equatorial region, assumed that the postglacial 

warm-water type of ooze began to accumulate there 

about 20,000 years ago. He calculated the average rate 

of accumulation of globigerina ooze in 48 cores to be 

approximately 1 centimeter in 415 years, and the range 

to be from 1 centimeter in 235 years to 1 in 950 years. 

For 6 blue muds he got an average rate of about 1 

centimeter in 282 years, with a range from about 1 in 

151 to 1 in 556 years. For 7 red clays the average was 

about 1 centimeter in 584 years.

It is interesting to compare these estimates with an 

estimate by H. Lohmann 39 based on the population 

and rate of growth of the Coccolithophoridae, published in 1909. Many assays of the plankton population showed that about 500 million of these minute 

calcareous plants grow under each square meter of 

open sea in the North Atlantic. These divide, on the 

average, about every 3 days, and as their total number, 

year in and year out, remains nearly constant, about 

one third of the population dies and sinks each day. 

From this rate and from the volume of the tiny plates 

or coccoliths into which the limy shells separate after 

the death of the organism he calculated that if the 

bottom deposits consisted of coccoliths alone they 

would accumulate at the rate of one millimeter in 

1,000 years. But in the oozes he examined he estimated that coccoliths made up 30 to 70 percent of the 

sediment, which would mean that the sediment accumulated at something like 1 millimeter in 300 to 700

ss Schott, W., Die foraminiferen in dem Squatorialen Teil des Atlantischen Ozeans: 

Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 3, Lief. 1, 

p. 129, 1935.

3» Lohmann, H., Plankton-Ablagerungen am Boden der Tiefsee: Nf.turwiss. Ver. 

Schleswig-Holstein Schr., Band 14, pp. 399-403,1909.
14 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

years, or at an average rate of about 1 millimeter in 

500 years. Although his samples came from depths 

of 2,400 to 4,800 meters in the North Atlantic, few of 

the samples from our cores contained more than 10 

percent of coccoliths and most of them contained less. 

According to Correns,40 Schott also estimated from 

the Meteor samples that the coccoliths, even where 

most abundant, made up not more than 13 percent of 

the total. If it be assumed the coccoliths make up 10 

percent of the sediment now accumulating, Lohmann's 

figures would indicate a rate of about 1 millimeter in 

100 years or 1 centimeter in 1,000 years. Probably a 

coccolith content of 3 percent would be nearer the 

average value for the sediment in the upper parts of 

cores 4 to 7, and this would indicate a rate of accumulation of about 1 centimeter in 300 years. This estimate, like the others, is obviously subject to considerable error, yet it is of the same order of magnitude as 

those given above, which were reached by a quite different line of reasoning.

The rate in the open ocean, as might be expected, is 

much slower than in inland seas or fjords, where more 

clastic material is supplied; for example, in the Clyde 

Sea 41 the varves in the mud indicate that the mud 

there accumulates at the rate of 1 centimeter in 2.1 

years, whereas in Drammensfjord, Norway,42 the 

varves indicate an accumulation rate of one centimeter 

in 6.7 years. In some of the larger inland seas the 

rate is apparently more nearly comparable with oceanic 

rates, as is illustrated by the deeper parts of the Black 

Sea, where, according to Archanguelsky, 43 the varves 

indicate an accumulation rate of about 1 centimeter 

in 50 years for the kind of ooze now being deposited.

EVIDENCE OF BOTTOM CURRENTS

The texture and structural features of the sediments 

in several parts of these cores seem to indicate rather 

plainly that, locally, currents move over the sea bottom 

with sufficient velocity to sweep the finer particles 

from the higher rictges and scatter them about over the 

bottom of the adjacent deeper parts of the ocean. 

The evidence for these currents is manifested most 

clearly in core 8, which was taken at a depth of 1,279 

meters of water on the top of the Faraday Hills—a 

part of the mid-Atlantic ridge—and in core 13, taken 

at a depth of 1,955 meters on the continental slope off 

the Irish coast. (See fig. 1.) In these two cores the 

sediment contains an unusually large proportion of 

sand, the calcareous organisms are predominantly of

« Correns, C. W., Die Sedimente des Squatorialen Atlantischen Ozeans: Wiss. 

Ergeb. Deutschen Atlantischen Exped. Meteor, 1926-27, Band 3, Teil 3, Lief. 2, pp. 

208-209, 1937.

« Moore, H. B., The muds of the Clyde Sea area: Jour. Marine Biol. Assoc., Plymouth, vol. 17, No. 2, new ser., pp. 348-351,1931.

« Str0m, K. M., Land-locked waters: Norske vidensk.-akad. Oslo, Skr., 1936, 

No. 1, fig. 41, 1937.

43 Archanguelsky, A. D., On the Black Sea sediments and their importance for 

the study of sedimentary rocks: Soc. naturalistes Moscou Bull., sec. Geol. new ser., 

tome 35, pp. 276-277,1927.

sand size, and there is relatively so little binding matrix 

of clay-size material that the dry sediments are friable. 

These features are less obvious from the graphical 

illustration of the mechanical composition shown in 

plate 3 than they are when one examines the dry material under a binocular microscope, because a considerable proportion of the clay-size material is within the 

tests of the Foraminifera.

Evidently bottom currents move across these two 

core sites, winnow out most of the finer material, and 

carry it into deeper water. The evidence for this 

action is to be found not alone in the texture of the 

sediments of these two cores but more particularly in a 

comparison of the texture of core 8 with that of the 

next adjacent core 9, which, though relatively near, as 

shown in the profile (fig. 1), was taken at a depth of 

3,745 meters of water. The postglacial zone in core 9 

is more than 10 times as thick as it is in core 8, and it is 

made up predominantly of very fine grained material, 

as the data from the mechanical analyses plotted in 

plate 3 show. That much of this fine material came 

from the top of the mid-Atlantic ridge is suggested by 

the abnormal abundance of volcanic glass shards in 

core 9. These shards are mostly small and delicate, 

whereas the upper ash zone of core 8 contains but few 

shards arid those are coarse and heavy. As the shards 

were brought to the ocean through the air, their distribution in the surface water was presumably uniform, 

therefore the sorting between cores 8 and 9 must have 

been subaqueous. Moreover, the scarcity of fine 

material in the sediment at the site of core 8 strongly 

suggests that the currents that did the winnowing 

were bottom currents.

Diatoms, coccoliths, and other minute organisms are 

rare in core 8, but they are abnormally abundant in 

core 9. These organisms are all minute and, like the 

volcanic ash shards, have large surface area with respect to their weight. Therefore, it seems probable 

that they also were removed from the Faraday Hills 

and concentrated in the deeper water by the same 

currents that brought the other fine material. The 

possibility has been suggested that for some ecological 

reason the surface waters just east of the Faraday Hills 

were particularly favorable for the growth of these 

organisms but it seems unnecessary to postulate such 

a special explanation to account for their concentration 

at the site of core 9.

The occurrence of coarser-grained sediment on the 

tops of ridges and mounds and fine-grained sediment in 

the deeper basins and depressions is apparently a common relationship.44 Correns' work 45 on the many deepsea samples of the Meteor expedition also showed that 

the coarser-grained sediment was found on the ridges

« Trask, P. D., Origin and em'ironment of source sediments of petroleum, pp. 

87-94, Houston, The Gulf Publishing Co., 1932.

45 Correns, C. W., Anzoichen von Beziehungen zwischen Stromungen uud Bildung 

kustenferner (eupelagischer) Sedimente: Neues Jahrb., Beilage-Band 57, Abt. A, 

pp. 1113-1117,1928.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 15

and swells of the ocean floor, and this relationship was 

interpreted by him as a result of deep-sea bottom currents. He also showed that in areas where Foraminifera 

made up most of the sediment the deposits on ridges 

and mounds were richer in lime than those deposited 

in the adjacent basins, because the currents swept away 

the less calcareous clay fraction from the ridges.

The depth of 1,280 meters on the top of the midAtlantic ridge, where core 8 was taken, is almost surely 

too great for any surface wave effects, and the deep 

circulation of polar water southward is estimated 46 to 

be too slow to have much effect on the bottom. The 

effects of tidal currents, however, at these depths may 

be considerable, and deserve further investigation. 

Murray and Hjort 47 wrote "We now know that tidal 

currents prevent the formation of muddy deposits on 

the top of the Wyville-Thompson Ridge in depths of 

250 to 300 fathoms, while just below the summit of the 

ridge on both sides mud is deposited." Tidal currents 

might be significant at even great ocean depths where 

ridges constrict the cross section of a large volume of 

slowly moving water.

The material in cores 8 and 13 is considerably more 

oxidized than in the other cores. They are stained with 

hydrous iron oxides and some manganese oxide, and 

they contain no iron sulphide. This relatively greater 

degree of oxidation apparently reflects the continual supply of oxygen from the water that circulates freely over 

these parts of the sea floor. Near the site of core 13 the 

Michael Sars dredged cobbles and boulders that appeared to have been only partly buried in the globigerina ooze.48 Above a well-defined line these cobbles 

are stained with iron and manganese oxides, and to 

them are attached siliceous sponges, serpulae, horny 

worm tubes, and hydroids. These cobbles were 

dropped there from floating ice. Peach thought they 

probably fell into a flocculent ooze and sank until they 

reached a more tenaceous layer. Results of the present 

study suggest that it is perhaps more probable that they 

fell into glacial marine deposits and were subsequently 

covered, or partly covered, with globigerina ooze. 

That part of the interpretation is, however, much less 

pertinent than how they continue to remain partly 

emergent. Peach wrote: 49 "Their presence at the surface is probably due to a current that is just strong 

enough not only to sweep away the falling pelagic 

organisms that mainly go to form the ooze, but also to 

denude some of the looser top deposit and partially to 

expose the stones." The thinness of the postglacial 

deposits in core 13 and the conspicuous amount of sand 

and pebbles that are mixed with the postglacial types of

48 Defant, A.. Uber die wissenschaftlichen Aufgaben und Ergebnisse der Expedition; die deutsche atlantische Expedition auf dein Forschungs- und Vermissungsschitl Meteor: Gesell. Erdkunde Berlin Zeitschr., pp. 362-366, fig. 53, 1927.

47 Murray J., and Hjort, J., The depths of the ocean, p. 170, London, Macmillan Co., 

1912.

48 Peach, B. N., Report on rock specimens dredged by the Michael Kara in 1910, by 

H. M. S. Triton in 1882, and by H. M. S. Kniyht Errant in 1880: Royal Soc. Edinburgh 

Proc., vol. 32, pp. 267-275,1913. « Idem, p. 272.

Foraminifera support Peach's interpretation that currents of appreciable velocity sweep the bottom close to 

the edge of the continental shelf.

Currents of sufficient velocity to move silt and sand 

sized particles may not be restricted to these more 

exposed parts of the sea floor but may also operate to 

an appreciable extent even at depths exceeding 4,820 

meters. The distribution of the shards of volcanic 

glass in both ash zones of these cores presents evidence 

that may be interpreted as the result of such currents. 

The shards that are scattered through a considerable 

thickness of sediment above the base of each ash zone 

may be so distributed because, for a long time, gentle 

currents continued to remove them from the tops of 

low mounds or ridges on the ocean floor and scatter 

them about over the adjacent flatter areas while the 

foraminiferal ooze continued to be deposited. This 

implies that, by reason of the currents, parts of an ash 

zone remain exposed for a long time on the mounds and 

ridges to supply shards to the adjacent areas. Such a 

hypothesis to account for the distribution of the shards 

in the ash zones might be tested conclusively in some 

particular locality by a group of cores that sampled 

the sediment on the top of a low ridge and on the 

adjacent flatter parts of the ocean floor.

Another and perhaps more plausible explanation of 

the distribution of the shards in the ash zones is given on 

pages 22-23 under the heading "Role of mud-feeding

organisms."

SUBMARINE SLUMPING

Several layers of sediment in these cores that are 

rather sharply set off from the adjacent material by 

distinctive textural changes suggest submarine slumps. 

Two of these are in core 5 (samples B-53 and B-55) 

and another in core 12 (bottom part of sample B-214). 

Sample B-53 consists of a mixture of sand and Foraminifera which contains so little fine-grained material 

that it is decidedly friable. It contrasts markedly with 

the underlying homogeneous clayey sediment, which 

contains very few Foraminifera. The contact between 

them is sharp, but the most distinctive feature of 

sample B-53 is its gradation in grain size from coarsest 

at the base to fine at the top, as is shown in table 2.

TABLE 2.—Grain-size distribution in sample B-58 from core 5 and 

approximate composition

Distance 

above 

base of 

sample (centimeters)

8—- — ._

7

6

5

4 . -----

3..— .—

2—._ — _

1

0 - - .

Average diameter (millimeters)

Clastic 

grains

0.06

.09 

.11 

.13 

.14 

.18 

.28

.46 

.45

Foraminifera

0.24

.25 

.24 

.23 

.25 

.27 

.27

.32 

.39

Mud 

pellets

SmallSmall . 

0.4__-_

.9— . 

.8.--.

Composition (percent, 

estimated)

Foraminifera

30

30 

40 

65 

60 

60 

55

75 

55

Clastic 

grains

45

70 

60 

35 

40 

40 

42

3 

40

Clay 

pellets

Rare.- 

Rare.-

2-..._.

20- — - 

5__ ——

Other constituents

Finely comminuted 

foraminiferal shells, 

25 percent.

Basaltic glass scoria, 

1 percent. 

Basaltic glass scoria, 

2 percent.
16 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

The regular gradation in size of this material, the 

sharp boundary at the base, the irregular occurrence of 

clay pellets, and the gradation into material of yet 

finer grain above suggest that this sample consists of 

material thrown into suspension by a submarine slump, 

carried beyond the slide itself, and deposited rapidly. 

Material thus thrown into suspension would be expected to settle according to the respective settling 

velocities of the various constituents. Clouds of suspended sediment are known to have travelled far 

beyond the outermost limit of subaqueous slides in 

lakes.50 The average slope of the lake bottom over 

which one of these slides moved was a little less than 5 

percent. Archanguelsky 51 describes numerous subaqueous slides in the sediments of the Black Sea and 

says they "seem to exist wherever the inclination of 

the bottom attains 2° to 3°, but at places occur even 

there, where the angle of the slope does not exceed 1°." 

Schaffer 52 cites apparently good reasons for believing 

that submarine slides have occurred off the Spanish 

and Portuguese coasts. Stetson and Smith 53 have 

recently referred to a large submarine slide which 

broke the Western Union Telegraph Go's, cable off the 

Newfoundland Banks following the earthquake of 

November 1929.

Another reason for thinking that the material in 

sample B-53 was derived from a submarine slide is the 

anomalous temperature indicated by its Foraminifera. 

The analysis of these Foraminifera by Cushman and 

Henbest indicates surface water temperatures warmer 

than prevail there today; whereas the Foraminifera in 

all other samples from the zone between the uppermost 

two glacial marine zones in cores 4 to 7 indicate temperatures nearly, or quite, as cold as in the glacial marine 

zones. (See pi. 4.) The presence of these warmerwater Foraminifera at this place in the core suggests 

that the sliding segment of mud—perhaps from a 

steeper part of the slope between cores 4 and 5 (see 

fig. 1)—was thick enough when it broke away from the 

slope to include at its base part of a layer of warm-water 

sediment similar to, or perhaps actually correlative 

with, that which makes up the lowest parts of cores 4 

and 5.

Sample B-55, also in core 5, is sharply set off from 

the adjacent mud by its coarser grain and friability, by 

its greater abundance of Foraminifera, Radiolaria, 

coccoliths, and alkalic volcanic glass shards, and by its

50 Heim, Arnold, tiber rezente und fossile subaquatische Rutschungen und deren 

lithologisehe Bedeutung: Neues Jahrb., 1908, Band 2, pp. 137-140. Nipkow, F., 

tiber das Verhalten der Skellete planktischer Kieselalgen und geschichteten Tiefenschlamm des Zurich—und Baldeggersees: Rev. Hydrologie, 4 annfie, pi. 1, pp. 114-115, 

1927.

«i Archanguelsky, A. D., Slides of sediments on the Black Sea bottom and the importance of this phenomenon for geology: Soc. naturalistes Moscou Bull., Sci. G6ol. 

new ser., tome 38, p. 80,1930.

52 Schaffer, F. X., Uber subaquatische Rutschungen: Centralbl. Mineralogie 1916, 

Abt. A, p. 24.

53 Stetson, H. C., and Smith, J. F., Behavior of suspension currents and mud 

slides on the continental slope: Am Jour. Sei., 5th ser., vol. 35, p. 12,1938.

ill-defined lamination. This layer is as sharply defined 

at the top as at the base and has no discernible upward 

gradation in grain size. These features suggest that it 

resulted from a slump comparatively nearby, the finergrained particles of which were carried beyond the site 

of this core. The presence in this layer, about midway 

between the upper and lower ash zones, of more shards 

of alkalic volcanic glass than in the adjacent sediment 

suggests that this slump, at its source, may have cut 

down into the lower ash zone. Such a layer might also 

be explained as a product of a local bottom current 

which, for some unknown reason, flowed more rapidly 

for a time and then either shifted its course or ceased 

to flow; but the abruptness of the change from one 

kind of sediment to another at both top and bottom of 

this layer makes this explanation less plausible. Near 

the bottom of core 3 is a sharply defined silty layer with 

obscure lamination which, though it consists largely of 

terrigenous silt, is similar in texture to B-55 in core 5 

and presumably had the same origin. (See pi. 2.)

A very thin layer in the bottom part of sample, 

B-214, which was taken from a thick glacial marine 

zone in core 12, is like sample B-55 in being sharply 

defined at top and bottom and in showing no obvious 

upward gradation in grain size, though the material is 

somewhat coarser grained than the sediments immediately above and below. This layer at the base of 

sample B-214 contains more calcium carbonate, more 

coccoliths, and more shards of alkalic volcanic glass 

than the rest of the sample. Its Foraminifera indicate 

warmer water than the adjacent samples in the glacial 

marine zone within which it lies. (See pi. 4.) These 

facts, together with the distinctive texture and sharp 

boundaries of the layer, suggest either material that 

settled out from the suspended material of a submarine 

slump or perhaps material sorted by local and temporary currents. The presence of the alkalic glass shards 

suggests, as in B-55, that if it is the result of slumping, 

the slump may have carried down in its basal part 

material from a lower ash zone. But no matter how 

the shards got into sample B-214 it is plausible to 

assume that they provide evidence that the lower 

alkalic ash zone is present east of the mid-Atlantic 

ridge though none of these cores reached it.

Lower in core 12 the material from the general horizon 

of sample B-223 nearly to the bottom has a somewhat 

lumpy appearance and is sandy and friable. This part 

also contains small granules, some rather cleanly sorted 

fine reddish sand, and at least one red sandstone pebble 

more than a centimeter across. The texture and composition of the material in this part of the cote and the 

fact that the core was taken on the lower part of the 

continental slope (see fig. 1) suggests that this lumpy 

material may have slid from a position higher on the 

banks and that the slide included some glacial marine 

material. An alternative interpretation was given on 

page 7.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 17

CARBONATE CONTENT OF THE SEDIMENTS

The total amount of carbonate in these samples was 

determined by treating the material with hot dilute 

hydrochloric acid until the solutioft was slightly acid 

as indicated by methyl orange. The amounts of total 

carbonate plotted in plate 3 are therefore only approximate determinations, subject to errors of several percent. Among the variety of factors that introduce 

errors are the partial solubility and the base exchange 

of the clay minerals and the incomplete solution of carbonate particles by reason of clay films that protect 

them from the acid. The figures given for total carbonate include both calcium and magnesium carbonates, and in the following discussion "carbonate" 

refers to these amounts of total carbonate unless stated 

otherwise. Actually, the magnesium-carbonate content 

of the 31 samples in which it was determined averages 

only 2.19 percent, which is probably within the range 

of uncertainty of the total carbonate determinations, 

so that it may be neglected in the following consideration, and the total carbonate may be considered as all 

calcium carbonate. In support of this suggestion 

K. J. Murata of the Geological Survey's chemical laboratory has pointed out to us how closely the relationship of the CaO and CO2 in the 20 precise analyses given 

by Edgington and Byers in the chapter "Selenium 

content and chemical analyses" agree with the relations 

of CaO to CO2 in pure calcite. This relationship is 

shown in figure 5. Many of the points in this figure 

lie above the line of pure calcium carbonate. This 

suggests that a small part of the total calcium in the 

samples is present in a noncarbonate form. The 

points that fall below the line apparently represent 

magnesian calcite or mixtures of calcium and magnesium carbonate. Sample 5A12, for example, contains 

4.14 percent of MgCO3 , and samples 10A5, 3A9, and 

13A3 each contain several percent of MgCO3 . Sample 

10A4, which contains comparatively little carbonate, 

owes its anomalous position with respect to the line 

representing the composition of calcite to the abundance of basaltic debris in the mud. The rest of the 

samples approximate rather closely the composition of 

calcite.

Before considering the distribution of the carbonate 

it is desirable to consider briefly the terminology of 

carbonate-rich sediments. Murray and Chumley 54 defined globigerina ooze as deep-sea sediment that has a 

carbonate content of 30 percent or more. The average 

carbonate content of all their samples is 64.72. Correns 55 

points out that this means of defining globigerina ooze 

on the basis of carbonate content is unsatisfactory, 

because many deep-sea sediments contain 30 percent 

or more of carbonate, yet only a few Globigerina or any

84 Murray, J., and Chumley, J., The deep sea deposits of the Atlantic Ocean: 

Royal Soc. Edinburg Trans., vol. 54, pt. 1, p. 217, 1924.

66 Correns, C. W., Die Sedimente des aquatorialen Atlantischen O/eans: Wiss. 

Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 3, Lief. 2, pp. 

206-208, 1937.

228324°—40——3

other Foraminifera. As a substitute he proposes to 

define globigerina ooze by the foraminiferal number, 

which is the number of Foraminifera per gram within 

the size range 0.2 to 2.0 millimeters. Samples with a 

forammiferal number of 6,000 or more he calls globigerina ooze. This would mean that certainly more than 

a quarter and generally about half of the sediment 

would consist of foraminiferal shells. He found that 

most of the Meteor samples had a carbonate content of 

60 percent or more. According to this definition many 

of our samples should not be classed as globigerina

36 

32

28

24 

O

s

Id 

O

tr

td

a- 16

12

8 

4 

0

,

/

OA4* .'

/*

•/

/

/.10

•5AI2

t

•/•I3 

/3A9

A5

y

/

A3

/

/

/

4 8 12 16 20 24 Z8 32 

PERCENT C02

FIGURE S.—Graph showing the CaO-CO3 ratios of core samples (represented by dots) 

in relation to the CaO-COs ratio of pure calcite (represented byi;hp diagonal 

line). All data are from analyses made by Edgington and Byers, and the numbers 

by some of the dots are sample numbers given in their table of analyses.

ooze, but the Foraminifera in our samples have not 

been counted, and it is not possible to compare them 

directly with the Meteor samples. In this report the 

term globigerina ooze is used loosely to designate the 

sediment in which roughly half or more of the sediment, 

by weight, consists of Foraminifera. By bulk, these 

hollow shells are obviously the predominant constituent. 

Limy muds containing a lesser but still conspicuous 

number of Foraminifera are referred to by the more 

qualitative term "foraminiferal marl."

The tests of Foraminifera, most of which are nearly 

whole and thus easily recognizable, were estimated to 

make up approximately 47 percent, by weight), of the 

carbonate of the sediment that is classed as globigerina 

ooze in these cores, whereas in the globigerina ooze 

collected by the Challenger the Foraminifera (pelagic
18 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

and bottom-dwelling) make up 61 percent.56 For the 

North Atlantic samples the percentages of Foraminifera 

shown in plate 3 are rough estimates. In making these 

estimates there is a tendency to overestimate the percentage by weight, owing to the relatively large volume 

of the shells in proportion to their weight. A correction for this difference was attempted while making the 

estimates under a binocular microscope, and the fact 

that the small comminuted fragments of Foraminifera 

were not included in the estimates tends further to 

compensate for any overestimate of the weight of the 

whole shells. We believe, therefore, that these estimates, though subject to rather large errors, give a 

fairly reliable picture of the distribution of the Foraminifera in the cores.

Globigerina ooze blankets the sea floor in all parts 

of the North Atlantic where all these cores were taken 

except at core station 3, which is in the blue mud zone, 

and at core station 9 where the mud is very limy but 

contains relatively few Foraminifera. Similar globigerina ooze makes up the lower parts of cores 5, 6, and 

7, below the lowest glacial marine zone. The carbonate 

content of the globigerina ooze at the tops of the cores 

and in the lower parts of cores 5 to 7 ranges from 46.6 

percent to 90.3 percent by weight and averages 68.2 

percent. In the foraminiferal marl the average carbonate icontent is generally somewhat lower, but the 

range is large; for example, sample B-60 in core 5, 

contains 25.7 percent carbonate, and at the other extreme aire samples B-152 to 156 in core 9, which have 

an average carbonate content of 78 percent.

, The only oijher calcareous organisms that commonly 

form a quantitatively significant part of the calcium 

carbonate in these cores, are the minute algae belonging 

to the Coccolithophoridae. These are flagellate brown 

algae, the commonest of which have globular coatings 

or shells of calcium carbonate made up of plates. These 

plates, the coccoliths, separate readily when the plant 

dies, and in the sediment only these minute plates of 

various shapes are commonly found. The smallest of 

these coccoliths are only about 0.002 millimeter in 

diameter, and few of the largest exceed 0.015 millimeter 

in diameter. They belong to several different types 

among the many genera and species that have been 

described by Schiller.57 We have made no attempt 

to differentiate the various genera and species.

In the more calcareous sediments the coccoliths are 

usually common, but because of their small size they 

rarely constitute more than a few percent by weight of 

the total carbonate. Where they reach their maximum 

abundance in the upper parts of cores 9 and 3, they 

were estimated to make up about 10 percent of the sediment by weight. They can be recognized only at high 

magnifications, and as many hundred coccoliths would

56 Murray, J., and Chumley, J., op. cit., pp. 222-223.

87 Schiller, J., Coccolithineae: Rabenhorst's Kryptogamen-Flora, Band 10, Ab. 2, 

1930.

equal only one of the smaller Foraminifera, a careful 

separation into grade sizes and determination of the 

percentages within these fractions would be necessary 

to obtain satisfactory estimates. Therefore, only the 

relative abundance of the coccoliths, based on rough 

estimates, is shown in plate 3.

Rhabdoliths represent a type of calcareous algae 

living in warmer water, but none were observed in any 

of the samples.

A small number of echinoid spines and plates of their 

tests were noted in samples from most of the cores. 

Ostracodes are about equally rare, and shells and fragments of mollusks are still more rare. These are discussed further in the chapters on "Echinodermata," 

"Mollusca," "Ostracoda," and "Miscellaneous fossils." Pteropods constitute a few percent of the calcareous material in some samples, notably B-131 near 

the top of core 8, between samples B-225 and 226 in 

core 12, and B-231 in core 13. Calcareous organisms 

other than Foraminifera and coccoliths occur so sparingly that in most samples they are quantitively 

insignificant.

In the more highly calcareous samples, most of which 

are to be classed as globigerina ooze, it is obvious that 

the calcium carbonate consists predominantly of the 

tests and comminuted fragments of calcareous organisms, but the particles of calcite of fine silt size and 

smaller are only in part recognizable. The irregular 

shape and range in size of these indeterminate particles 

of calcite suggest that they are largely the finest debris 

of the comminuted organisms rather than a chemical 

precipitate of calcium carbonate. Particles resembling 

the aragonite needles described by Vaughan 58 from the 

Bahama Banks region, if present, are too rare to have 

been noted. The large percentage of calcium carbonate 

in some of the finer-grained sediment, such as that making up most of cores 3 and 9, is mostly of indeterminate 

origin. It seems probable that these fine-grained sediments would contain the largest amount of chemically 

precipitated calcium carbonate if any were to be found, 

but no adequate criteria for recognizing such a chemical 

deposit have been noted. The presumption is, therefore, that the greater part of this finely divided carbonate of irregular shapes and sizes consists of the most 

finely comminuted particles of calcareous organisms 

that have been winnowed out, along with other fine 

particles, from the Newfoundland Banks (core 3) and 

the mid-Atlantic ridge (core 9).

Well-formed crystals of calcite, commonly intergrown 

so as to form clusters or rosettes, have been noted in 

many of the samples, but in no sample are they abundant. Some of these calcite crystals are distinctly 

zoned. These obviously inorganic calcite grains are 

generally 0.1 to 0.2 millimeter in diameter. Because 

of their comparatively large size, crystal form, and

58 Vaughan, T. W., Chemical and organic deposits of the sea: Geol. Soc. America 

Bull., vol. 28, pp. 933-944, 1917.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 19

habit, it seems more probable that they are the result of 

growth within the mud than of chemical precipitate in 

the water above the mud or in the surface water. 

They form only a negligible portion of the carbonate 

content of the cores but seem to be more common in the 

glacial marine zones than elsewhere.

The large amount of chemical data on ocean water 

obtained by the Meteor expedition and discussed by 

Wattenberg 59 indicates that much of the water is approximately saturated with calcium carbonate under 

existing conditions of equilibrium, and a slight departure from these conditions may therefore cause precipitation. Revelle 60 has pointed out the possibility 

that Wattenberg's figure for the solubility-product constant of calcium carbonate in sea water may be somewhat too low and that, in consequence, less of the ocean 

water is saturated with calcium carbonate than Wattenberg believes. It is generally agreed, however, that 

the water at greater depths is not saturated and tends 

to dissolve carbonates. Accordingly, even though 

carbonates were precipitated at the surface of the ocean 

as tiny needles of aragonite, they would probably be 

redissolved before reaching the bottom, because this 

form of calcium carbonate is relatively unstable, particularly in minute particles. The high alkalinity determined by Wattenberg 61 for the water close to the 

bottom suggests solution of calcium carbonate, probably of the more finely divided particles and particularly those in the form of aragonite. The dissolved 

carbonates in these waters near the deep ocean bottom 

may thus reach a concentration sufficient to cause some 

reprecipitation of calcite crystals within the bottom 

sediments. It is noteworthy in this connection that 

shells of pteropods, which are composed of aragonite, 

are seldom found below a depth of 2,740 meters and are 

generally restricted to deposits formed in water shallower than that containing the remains of other pelagic 

organisms whose, shells are composed of calcite.62 

Pteropods were found only in cores 8, 13, and the lower 

part of 12, which are the cores from the shallowest 

water of the series. In cores 8 and 12 these pteropods 

occur in parts of the cores classed by Cushman and 

Henbest as warmer-water deposits. (See pi. 4.) The 

pteropod shells are well preserved in several samples of 

core 13, but in sample B-235 and between samples 

B-240 and B-241 their former presence is revealed 

only by clay casts of the shells. These samples from 

which the shells have been dissolved were taken from 

glacial marine zones, and it therefore appears that, like 

the present polar waters, the cold water of the glacial

'• Wattenberg, H., Kalciumkarbonate-und Kohlensauregehalt des Meerwassers: 

Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 8, Teil 2, pp. 

206-227, 1933.

so Revelle, Roger, Physico-chemical factors affecting the solubility of calcium carbonate in sea water: Jour. Sedimentary Petrology, vol. 4, pp. 105-106,1934.

M Op. cit., pp. 165-172.

62 Murray, J., and Chumley, J., Deep sea deposits of the Atlantic Ocean: Royal 

Soc. Edinburg Trans., vol. 54, pt. 1, p. 234,1924.

marine epochs was a more effective solvent of calcium 

carbonate than the warmer water of nonglacial epochs.

Among the pebbles and granules of the glacial marine 

deposits, the most common rock types are limestone 

and dolomitic limestone. Grains of these types are 

likewise recognizable in the sediments of coarse and 

medium sand sizes, in some of which they are estimated 

to make up 10 to 15 percent. If there is a similar or 

greater proportion of clastic limestone grains, in the 

grains of finer sand and silt size, as may be expected 

from the relative softness of limestone, it seems probable 

that clastic carbonate constitutes the major part of the 

carbonate content of the glacial marine deposits in 

which Foraminifera are few and coccoliths absent.

The amounts of MgO and CaO in the acid-soluble 

portions of 31 samples selected from the top, middle,and 

bottom of each core were determined quantitatively. 

The CO2 was not determined, but it was assumed that 

all the MgO was present in the form of carbonate. A 

small but unknown amount of the MgO calculated here 

as carbonate is doubtless present as exchangeable base 

obtained from the acid treatment of the sediment. 

Lacking the CO2 determinations it is impossible to say 

how much is exchangeable base.

The percentages of magnesium carbonate in these 31 

samples are given in table 3. The percentage of 

magnesium carbonate in the 20 samples of foraminiferal 

marl in which magnesia was determined ranges from 

0.63 to 2.66, and the average is 1.32 percent. In the 

blue mud of core 3 the average magnesium carbonate 

content is 3.46 percent, and the average for the 6 

samples of glacial marine deposits in which magnesia 

was determined is 4.01 percent.

TABLE 3.—Distribution of magnesium carbonate within cores 3 to 

13, percent

Position

of sample

in core

(approximate)

Top...— —

MiddleBottom _

3

2.59

3.11

4.67

4

1.25

54.85

1.55

5

0.9

34.14

1.8

6

1.33

35.19

2.66

7

0.94

1.38

.63

8

1.1.7

1.36

1.25

9

1.75

2.15

32.61

10

24.08

36.48

2 1.46

11

1.34

_._

-----

1.2

0.73

s.79

.88

13

1.09

1.25

.90

Average 1

1.31

1.85

1.79

1 Exclusive of the glacial marine deposits and the peculiar mud in COP; 10.

2 For peculiarities of this mud see pp. 32-34. 

s Glacial marine deposits.

The distribution of the magnesium carbonate with 

respect to depth in each core is shown in table 3. It is 

evident from this table that the blue mud of core 3, the 

glacial marine deposits of all the cores, and at least part 

of the peculiar mud in core 10 (see pp. 32-34), contain, 

on the average, considerably more magnesium carbonate than the rest of the sediment in the cores. The 

greater quantity of magnesium carbonate in the glacial 

marine deposits probably can be accounted for by 

the recognizable grams of dolomite and dolomitic 

limestone, though a part may perhaps be ascribed to
20 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

differential solution of fine-grained calcite with respect 

to fine-grained dolomite by the colder water of the 

glacial epochs. (See p. 9.) The greater content of 

magnesium calculated as carbonate in the upper and 

lower clayey mud zones of core 10 may be due to partial 

solution of the basaltic constituents that they contain 

in addition to the scattered shards of alkalic glass. 

(See pp. 32-34.) If we exclude from consideration the 

glacial marine deposits and the peculiar muds of core 

10, we find that cores 3, 4, 5, 6, 8, and 12, which have 

top and bottom sediments that are comparable in 

type, all show a slightly greater percentage of magnesium carbonate at the bottom than at the top. But in 

cores 7, 8, and 13 the middle samples contain more 

magnesium carbonate than the samples above or below 

them, and in cores 7 and 13 the bottom samples contain the lowest percentage for those cores.

Perhaps the uniformity in composition and texture 

of the sediment in core 3 makes the progressive increase 

of magnesium with depth in that core considerably 

more significant than the distribution of magnesium in 

any of.the other cores. The magnesium content in 

core 3 is not complicated by glacial marine deposits 

nor by zones of either alkalic or basaltic volcanic 

material. Further investigation of the distribution of 

magnesium in depth in the oceanic blue muds is certainly warranted for what light it may throw on the 

tendency toward dolomitization with age and depth of 

burial.

The analyses showing MgO are so few, however, that 

averages of the figures given in table 3 can hardly be 

conclusive as indicators of a possible tendency to 

diagenetic dolomitization with increasing depth below 

the sea floor, as was suggested by the increasing magnesium carbonate content of the reef limestone in the 

deep boring at Funafuti.63 The Funafuti boring, of 

course, represented a much greater range of depth than 

these cores.

The relation between magnesia and lime in these 

samples is not wholly consistent, yet it is generally 

true that the greater the percentage of total carbonates 

in the sediment the smaller the percentage of magnesia. 

This is in part, at least, an accidental relationship that 

depends upon the presence of clastic grains of dolomite 

and dolomitic limestone in the glacial marine deposits, 

which are relatively poor in total carbonates. Had 

some transporting agent dropped the clastic dolomite 

and dolomitic limestone grains into globigerina ooze 

the relationship would have been different. In part 

also the concentration of magnesia in the samples 

having relatively low percentages of total carbonates 

is due to the zones of peculiar mud in core 10. These 

muds contain less carbonate than any other samples 

in the series, yet by reason of their basaltic debris, they 

are relatively rich in magnesia. Analyses of the car63 Judd, J. W., the chemical examination of the materials from Funafuti, in The 

atoll of Funafuti, pp. 364-365, London, Koyal Soc., 1904.

bonates in core 3 illustrate the reciprocal relation of 

CaO to MgO in some of these core sediments. The 

uppermost sample in core 3 contains 40 percent CaCO3 

and 2.59 percent MgCO3 , the middle sample contains 

37.8 percent CaCO3 and 3.11 percent MgCO3 , and the 

bottom sample contains 29.1 percent CaCO3 , and 4.67 

percent MgCO3 .

The Challenger samples also contained a larger percentage of magnesia in those samples that contained 

relatively small percentages of total carbonates. This 

relationship was interpreted by Murray and Hjort 64 as 

probably due to preferential solution of calcium carbonate over magnesium carbonate.

As much of the carbonate in these samples was derived from foraminiferal shells it is interesting to compare the CaO-MgO ratios of the samples given in 

table 4 with the CaO-MgO ratios of analyzed foraminiferal shells. According to Clarke and Wheeler, 65 

the average lime-magnesia ratio of two samples each 

consisting of a single species of pelagic Foraminifera 

dredged from the ocean is about 35. These particular 

Foraminifera evidently contain much more magnesium 

carbonate than some of the globigerina ooze of the 

North Atlantic cores, as for example in the upper and 

lower parts of core 7, which consist predominantly of 

pelagic Foraminifera. (See table 4.) Murray and 

Hjort 66 in commenting on the fact that magnesium 

carbonate makes up only a small percentage of the 

total carbonate on the sea floor wrote: "Since the proportion of Mg to Ca, primarily in rocks and secondarily 

in river-waters, is much larger than this, it is clear that 

dissolved magnesium is accumulating in the ocean." 

Recent experiments in base exchange by A. C. Spencer 

and K. J. Murata 67 have shown that for certain pure 

clays each 100 grams of clay brought into the ocean by 

rivers adsorbs nearly 0.2 gram of Mg from the sea water. 

This amount of Mg abstracted from the sea water is 

added to that which the fine clastic particles had 

already adsorbed when they were constituents of soils 

and which they held while in transit. Thus, as most 

of these particles are deposited in the zone of terrigenous deposits relatively near the coast, they fix 

therein whatever adsorbed Mg they brought with 

them from the land and also an additional amount which 

they adsorbed from the sea water. This may explain 

in part why there is relatively more Mg in the blue 

mud of core 3 than in the other limy sediments more 

remote from the coast. The base-exchange experiments also showed that when this same clay was transferred from normal river water to sea water it released 

about 0.9 gram of Ca for each 100 grams of clay. Thus 

more Ca and less Mg is delivered to the ocean water

6* Murray, J., and Hjort, J., The depths of the orean, p. 181, London, Macmillan 

Co., 1912.

65 Clarke, F. W., and Whi.-eler, W. C., The inorganic constituents of marine invertebrates: U. S. Qcol. Survey Prof. Paper 124, p. 2, 1922.

ee Op. cit., p. 181.

w Spencer, A. C., and Murata, K. J., oral communication.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 21

than chemical analyses of river water alone indicate. 

If this additional Ca brought into the ocean is precipitated as carbonate, for example, it may account, 

in part, for the greater excess of Ca over Mg in the 

deep-sea sediments. As noted above, because we lack 

the CO2 determinations, it is impossible to say how much 

of the Mg and Ca are present in these samples as carbonates and how much as exchangeable base obtained 

from the acid treatment of the samples.

TABLE 4.—Lime-magnesia ratios (to the nearest whole number of 

the samples shown in table 3)

.Position of sample in 

core (approximate)

Middle...............

3

18

14

7

4

59

25

23

5

14

26

34

6

fiO

25

27

7

ion

32

106

8

51

34

2fi

9

44

34

28

10

13

27

17

11

49

12

118 228

44

13

CO

52

52

1 For peculiarities of this mud see pp. 32-34. 

! Glacial marine deposits.

SULPHATES

K. J. Murata called our attention to the fact that 

the SO3 reported by Edgington and Byers (see chapter 

on "Selenium content and chemical analyses") is 

roughly twice as much as would be expected from the 

amounts of Cl if the SO3 /C1 ratio were the same in the 

entrained sea salts as it is in sea water. Abnormally 

large quantities of SO3 were also found in another core 

sample analyzed by E. T. Erickson in the Geological 

Survey's chemical laboratory. A number of corals, 

echinoderms, bryozoa, and other calcareous marine organisms contain appreciable quantities of sulphate 68 

and Mr. Murata suggested that the excess sulphate in 

these core samples might be a part of the normal composition of the calcareous foraminif eral shells and coccolith tests. As a result of this suggestion, J. J. Fahey, 

of the Geological Survey's chemical laboratory, determined the SO3 in three fractions of a sample of globigerina ooze (W-17, core 10; see pi. 3). Two fractions 

consisted almost wholly of foraminif eral shells, but the 

third fraction consisted of the material that had passed 

through a 200-mesh screen. All three fractions contained SO3 but definitely less than 0.01 percent. In 

preparing this sample (W-17) for mechanical analysis 

the entrained sea salts had been thoroughly leached out 

with large volumes of distilled water. Analyses of the 

leachate of several other samples from various cores 

contained, like the fusion analyses of Edgington and 

Byers, nearly double the amount of SO3 that would be 

expected. These facts suggest that the sediments contain small quantities of a soluble sulphate, possibly gypsum. Bannister 69 reported euhedral gypsum crystals 

from the Weddell Sea sediments, but we did not recognize any during the microscopic examination of the 

North Atlantic sediments. To be sure, there remains 

the possibility that calcium sulphate makes up a small

e, F. W., and Wheeler, W. O., The inorganic constituents of marine invertebrates: II. S. Geol. Survey Prof. Paper 124, pp. 7-56, 1922.

69 Bannister, F. A., Report on some crystalline components of the Weddell Sea 

deposits: Discovery Repts., vol. 13, p. 66, 1936.

part of the calcareous shells and that the long leaching 

removed it from them.

SILICEOUS ORGANISMS

The remains of siliceous organisms generally form 

less than 1 percent of the sediment of the cores. Diatoms, Eadiolaria, and sponge spicules are the most 

common forms, and any one or another of them may 

be the most numerous in a given sample. In cores 8 

and 13 sponge spicules are the only siliceous remains, 

but these spicules are relatively coarse and heavy as 

compared with the diatoms. The presence in these 

two cores of only the spicules—the heavier forms—is 

apparently to be explained as a residual enrichment, 

the lighter diatoms, Radiolaria, and other small 

particles having apparently been swept awajr by the 

currents that move over these sites. (See pp. 14-15.) 

In contrast with the rarity of diatoms in core 8, these 

delicate siliceous tests are unusually abundant in core 

9, only a little farther to the east. Indeed, the sediment in some of the middle part of core 9 may properly 

be classed as diatom ooze, as diatom frustules make up 

50 percent or more of it. This most diatomaceious part 

of core 9 is in the lower part of the upper volcanic ash 

zone. In core 10, the upper volcanic ash zone also 

contains thin beds in which diatoms are unusually 

abundant. West of the mid-Atlantic ridge diatoms 

are rather more common in the upper ash zone than 

in other parts of the cores, though much less common 

than in the ash zone of cores 9 and 10. This is another 

illustration of the common association of diatom 

remains and pyroclastics which has been pointed out 

by Taliaferro 70 and others.

Lohman's systematic work on the diatoms in these 

cores (see chapter on "Diatomaceae") shows that 

these bottom deposits contain no remains of the very 

delicate forms that constitute a large element of opensea pelagic diatom flora. This agrees with the findings 

of Brockmann 71 and with his interpretation that the 

tests of the more delicately silicated diatoms are 

dissolved before reaching the bottom, even in relatively shallow water, such as that of the North Sea. 

In the lower parts of several of the cores some of the 

diatoms had apparently been leached out after burial 

on the sea floor, for shallow cavities that appeared to 

be molds of frustules were observed in the clayey 

matrix. More study is required, however, to establish 

definitely that the silica of the diatoms was removed 

after burial. In certain samples also the central canals 

of sponge spicules appeared to be corroded. Enlargement of sponge-spicule canals by solution on the sea 

floor has been described by Schulze.72

70 Taliaferro, N. L., The relations of voleanism to diatomaceous und associated 

siliceous sediment?: California Univ. Pub., vol. 23, No. 1, pp. 1-55,1933.

'i Brockmann, Chr., Dialomoen und Schlick im Jade-Gebiet: Senckenberg, 

naturf. Gesell. Abh. 430, p. 6, 1935.

» Schulze, F. E., Report on the Hexactinellidae: Challenger Kept., Zoology, vol, 

21, pp. 26-27, 1887.
22 GEOLOGY AND BIOLOGY OP NORTH ATLANTIC DEEP-SEA CORES

ROLE OF MUD-FEEDING ORGANISMS

Apparently mud-feeding animals have played a significant part in reworking the sediment, even on the 

floor of the abyssal parts of the ocean. This seems to 

be best illustrated by the distribution of the volcanic 

ash shards in both ash zones, although an alternative 

explanation for the distribution of the shards was 

suggested on page 15. We know that explosive 

eruptions of volcanoes are brief episodes and that when 

the ash from them falls into quiet water it accumulates 

in thin, sharply defined layers, as indicated in figure 

6, A. The glass shards in the deposits of the North

A B

FIGUEE 6.—Diagram showing distribution of volcanic ash shards in sediments. A, 

Ash shards that accumulated in quiet water from two explosive eruptions; B, ash 

shards from two similar explosive eruptions that accumulated in water where mudfeeding animals continually worked over the sediment while ash-free sediment 

continued to accumulate so that the shards were incorporated in successively 

younger deposits. For an alternative explanation of this distribution of the shards, 

see p. 15.

Atlantic, however, are not so concentrated in thin 

layers; instead, they are distributed as shown in figure 

6, B, with the greatest concentration at the base in one 

or several ill-defined layers and the remainder scattered 

at random up through a considerable thickness of sediment above. One might think that this distribution is 

due to differential settling of the shards through several 

thousand meters of water. This seems improbable, 

however, as many of the shards are half a millimeter or 

more across, and they show no size gradation upward 

in the sediment but are apparently quite unsorted. A 

more conclusive argument against differential settling 

is as follows: The columns in figure 6 are so drawn that 

the interval through which the shards are scattered 

represents nearly all postglacial time, that is, thousands 

of years. A calculation based on Stokes' law shows

that the shards in these ash zones would have reached 

the bottom in less than 5 years.

We infer that mud-feeding animals living on the sea 

floor at the time the ash layer was newly formed must 

have passed through their intestines mud consisting 

largely of ash shards and that succeeding generations of 

these animals picked up progressively fewer shards as 

the sediment became more and more diluted by the 

continual influx of the normal constituents of foraminiferal marl. Each time an animal scooped up mud and 

later excreted it on the sea floor, most of the mud 

particles must have been deposited at a level a little 

above their original position. Apparently it was this 

raising by successive small increments that eventually 

resulted in the distribution of the shards through a 

considerable thickness of overlying sediment. Grains 

of fine sand and even some coarse grams are scattered 

through the zones of foraminiferal marl between and 

above the layers of glacial marine sediment. Presumably these grains were originally deposited in the glacial 

sediment but, like the ash shards, have been reworked 

into younger sediments. Probably detritus of other 

lands, including the shells and spicules of animals, has 

been similarly reworked, but it is difficult or impossible 

to tell how much their positions have been shifted.

The animals that are supposed to have performed 

this work are, of course, not known, but it seems 

probable from what is known of the abyssal fauna today 

that holothurians were largely responsible, though 

echmoids, annelids, and ophiurids doubtless also contributed. The*el 73 wrote:

But the first inspection [of the Holothuroidea dredged by the 

Challenger] made it evident that the forms from great depths, 

now displayed for the first time, were of the greatest interest by 

making it manifest that holothurians are living there not merely 

in great numbers but belonging to many species, and that a large 

majority of them present certain peculiarities that render them 

strikingly different from the littoral forms hitherto known, and 

make them constitute perhaps the most characteristic group of 

the whole abyssal fauna.

All of these deep sea forms belong to one order, the 

Elasipoda, of which he wrote further: 74

It is evident that some of the Elasipoda, living together in 

great multitudes, pass along the bottom of the sea; this seems 

especially to be the case with Laetmogone wyville-thomsoni and 

L. violacea, Oneirophanta mutabilis, several species of the genus 

Benthodytes, Kolga nana, Scotoplanes globosa, etc., of which great 

numbers have sometimes been dredged at the same station. But 

numerous different species were also found together; thus, no less 

than ten forms were obtained from station 157, five from station 

158, six from station 160, six from station 298, etc. The nature 

of the bottom of the sea is doubtless of great importance in 

regulating the distribution of the Holothuroidea, and they are 

found most numerous and in greatest abundance on a bottom of 

red clay, globigerina ooze, or diatom ooze.

Most of these came from depths ranging between 

1,825 and 5,300 meters.

73 Theel, Hjalmar: Report on the Holothurioidea dredged by H. M. S. Challenger 

during the years 1873-1876, Parti: Challenger Kept., Zoology vol. 4, p. 1, 1882.

74 Idem, p. 9.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 23

The calcareous plates of holothurians were found in 

the cores but they were much less numerous than fragments of echinoids and ossicles of ophiurids. It may 

be that the large surface per unit volume of the limy 

plates, wheels, and spicules of the deep-sea holothurians 

has been responsible for their disappearance by solution 

rather than that the animals themselves were scarce. 

Murray and Renard,75 in discussing the occurrence of 

organic remains in deep-sea deposits said:

Representatives of the various orders of Echinodermata are 

widespread over the sea bottom at all depths, and one would 

expect to find their remains somewhat abundant in the deposits 

now forming in the ocean; like Crustacea, however, the areolar 

nature of the shells seems to determine the removal of the hard 

parts in solution shortly after the death of the animal. It is 

seldom that a large sample of Globigerina ooze or Pteropod ooze 

can be examined without some fragments of Echini spines being 

observed, but it is the exception to meet with any other remains 

in the deep-sea deposits.

If the sediments in these cores have been as much 

reworked by mud-feeding animals as we infer from the 

distribution of volcanic ash shards and sand grains, we 

might expect them to have a more or less well-defined 

coprolitic structure. Ellipsoidal and elongate or cylindrical pellets that appear to be fecal peUets are plentiful in the mud at the top of cores 10 and 12. (See pi. 

5, A and B.) They were not found elsewhere. Some 

of the elongate forms shown in plate 5 may be filled 

borings. Considerably larger ellipsoidal and somewhat 

irregularly shaped pellets are rather characteristic of 

the sediment in the glacial marine zones. Whether 

these are fecal pellets or filled borings is not clear. 

No attempt was made to identify any of these pellets 

with the fecal pellets described by Moore 76 and 

Galliher.77

Inasmuch as these pellets that appear to be of fecal 

origin are restricted to parts of the cores that contain a 

rather large percentage of clay it suggests that only 

excreted pellets containing enough clay to act as a 

binder persisted long enough to be preserved. It 

seems probable that fecal matter bound only by 

mucous or other organic substances that could serve 

as nutriants for bacteria would be entirely disaggregated before they could be buried on the ocean floor, 

where sedimentation is so slow. This might account 

for the absence of coprolitic structure in the foraminiferal marl.

In addition to the work done in redistributing various 

constituents of the sediments, mud-feeding animals 

probably also are responsible, along with free-swimming 

animals in the water above, for the comminuted particles of foraminiferal shells and other small shells 

found in the foraminiferal marl.

" Murray, J., and Renard, A. F., Deep-sea deposits, Challenger Rept., p. 265,1891.

7« Moore, H. B., The specific identification of faecal pellets: Marine Biol. Assoc. 

United Kingdom Jour., vol. 17, No. 2, pp. 359-305, 1931; The faecal pellets of the 

Anomura: Royal Soc. Edinburgh Proc., vol. 52, pt. 3, pp. 29&-308, 1932.

77 Galliher, E. W., Organic structures in sediments: Jour. Sedimentary Petrology, 

vol. 2, pp. 46-17, 1932.

MINERALOGY OF THE CLASTIC SEDIMENTS

No systematic study of the mineralogy of the clastic 

grains was made, but notes were taken on the mineral 

components of the sand in many samples. The examination of the sand-size material was sufficient to show 

that the mineralogy of the clastic grains did not differ 

markedly from one horizon to another within individual 

cores and also that it did not differ conspicuously from 

core to core. More detailed study, however, would probably show a greater difference in the mineral content 

of sediments from the eastern and western parts of the 

North Atlantic than was evident in the examination 

given them. Casual examination, for example, showed 

that grains and pebbles of red sandstone arc, rather 

common in cores 12 and 13, whereas they are rare or 

absent from the cores in the middle and western parts 

of the North Atlantic.

In general, quartz is more plentiful than the feldspars. The feldspars include orthoclase, microcline, 

sanidine, and plagipclase feldspars ranging from albite 

to labradorite. The mineral grains in the sand-size 

portions of the samples were not separated ir.to light 

and heavy fractions. However, simple inspection 

showed that grains of heavy minerals are rattier common in the glacial marine deposits. In many samples 

of the glacial marine deposits the content of heavy 

minerals was estimated to be 5 to 10 percent, but in 

the sand between and above the glacial marine deposits 

it seemed to be generally less. Quantitative data on 

this relationship might indicate whether or not the 

sand in the nonglacial deposits was material that had 

been reworked from glacial marine deposits.

Green hornblende is the most plentiful hea.vy mineral, particularly in samples west of the mid-Atlantic 

ridge. Augite, hypersthene, and diopside are fairly 

common. Black opaque minerals consisting largely 

of magnetite and ilmenite are plentiful, as are also, 

micas. Epidote, apatite, and garnet are less common 

but were found in all samples examined. Olivine was 

found in some samples, but it is rare, particularly in 

the cores from the western part of the North Atlantic. 

The rarer minerals, whose relative abundance in 

different samples could not be even roughly compared 

without first separating and concentrating the heavy 

minerals, include sillimanite, kyanite, zircon, rutile, 

titanite, and tourmaline. Nevertheless, the relatively 

small proportion of such common heavy minerals as 

zircon and tourmaline is noteworthy.

Throughout the cores, but especially in the glacial 

marine deposits, well-rounded sand grains, mostly of 

quartz though in part of feldspar (usually microcline), 

are rather common. These range from about 0,1 to 

1.0 millimeter in diameter, but those with diameters 

of about 0.5 millimeter are most plentiful. The rounded 

grains generally have a more or less distinctly frosted 

surface common to grains that have been rounded by 

either wind or water. The proportion of weH -rounded
24 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

sand grains seems to vary only a little either vertically 

within the cores or laterally from one core to another.

Stetson 78 has recently described a remarkable concentration on the outer edge of the continental shelf off 

New England of very well-rounded quartz grains that 

have a mat surface and that range in diameter from a 

little less than 0.3 millimeter to a little more than 1.0 

millimeter. These grains decrease in abundance both 

seaward and landward but were found in cores taken as 

far down as the bottom of the continental shelf, at 

depths exceeding 6,000 meters. They are virtually 

absent, however, from a wide strip of the continental 

shelf adjacent to the coast and also from the beach 

sands and even the dunes on Cape Cod. Stetson interprets these deposits of well-rounded sand as remnants 

of an area of dunes formed during one or more times in 

the Pleistocene when the sea had retreated from the 

continental shelf and when periglacial winds were 

exceptionally strong.

Although the well-rounded, mat-surfaced sand grains 

in our cores are similar to those found on the edge of the 

continental shelf off the New England coast and 

although they may have come from the places where 

Stetson found them or from similar sites around the 

margin of the North Atlantic, they may quite as well 

have come from other kinds of deposits of rounded sand 

grains. The means by which these grains were distributed all across the North Atlantic and scattered 

through the glacial and nonglacial zones of sediment 

are not evident.

Although these grains may have been frosted, or 

both rounded and frosted, by wind action, it seems 

improbable to us that even large storms of exceptional 

violence could carry quartz grains of such size for great 

distances. Morover, if the rounded sand in our cores 

had been formed on the emerged continental shelves 

during glacial maxima and transported to the sites of the 

cores by great wind storms, by shore ice, or even by 

drifting seaweeds, it should now be restricted to the 

glacial marine zones. The fact that these rounded 

grains are scattered through both the glacial and iionglacial sediments suggests that they, along with other 

sand grains of similar size, were derived from reworking 

glacial marine deposits by mud-feeding animals. If, 

on the other hand, the rounded and frosted grains were 

not derived from deposits on the outer edge of the 

continental shelves but from some place nearer the 

present coast when the ocean level was higher than in 

glacial maxima, then there remains the possibility that 

they (and perhaps also the isolated pebbles found in 

deposits other than those of the glacial marine zones) 

were carried out to sea by drifting seaweeds, such as 

Fucus. It would be interesting to see if similar clastic

7 » Stetson, H. O., The sediments of the continental shelf off the eastern coast of the 

United States: Massachusetts Inst. Technology and Woods Hole Oceanogr. Inst., 

Papers in Physical Oceanography and Meteorology, vol. 5, No. 4, pp. 14-20, 34-36, 

1938.

material is common in the sediments of the Sargasso 

Sea, where seaweeds of this type are plentiful and glacial 

marine deposits are probably absent.

Little has been done with the clay minerals in the 

sediment of these cores other than to note that the 

minute flaky particles of the clay minerals commonly 

have the optical properties of the beidellite or hydrous 

mica groups. For one sample of the peculiar mud 

from the upper part of core 10 (sample W-15) P. G. Nutting of the Geological Survey determined a dehydration curve. This curve is shown in figure 7, with

1.00

100 200 300 400 500 6OO 70O 800 

TEMPERATURE(t.)

FIGURE 7.—Dehydration curves of basaltic mud from core 10 (sample W-15), a red 

clay from the Pacific Ocean (lat. 32°27' N., long. 145°30' W., depth 5,584 meters), 

and typical halloysite and montmorillonite from clay deposits in the United States. 

Data by P. G. Nutting.

the dehydration curves of typical samples of halloysite, montmorillonite, and a red clay from the 

Pacific Ocean. The steep uppermost parts of these 

curves represent adsorbed water, most of which is 

driven off at relatively low temperatures. The steep 

portions of the curves between 400° and 600° C. represent loss of water that was held within the crystal 

lattice of the mineral particles. Inspection of these 

curves shows that the halloysite type of clay contains 

much more crystal lattice water than the montmorillonite clay and also that the mud from the North Atlantic 

core 10 con tarns a quantity of crystal lattice water 

more nearly like that of halloysite than montmorillonite. 

That the bench between 100° and 400° C. on the curve 

of sample W-15 is lower than the comparable bench on
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 25

the curve for halloysite, Nutting 79 believes to be due 

probably to the mixture of the silt- and clay-size particles 

of basaltic minerals and glass with the clay minerals. 

The form of the curve, although determined largely by 

the clay minerals, is probably modified by the dehydration of the basaltic glass. The moderate slope 

between 400° and 570° C. may also be due to the dehydration of the basaltic glass, but it may be due in part 

to the minute size of the clay flakes—indeed, some of 

the clay appears even at high magnification to be gellike and virtually isotropic. This gel-like material, 

however, is filled with distinct but very small crystalline 

flakes. Most of these flakes are so thin that they 

appear to have a very feeble birefringence, but larger 

and thicker flakes show the higher birefringence that 

characterizes a beidellite or hydrous mica type of clay. 

Adequate discussion of the clay minerals in these 

sediments must await more study than we were able 

to give them.

In the Atlantic bottom samples collected by the 

Meteor, montmorillonite, halloysite, and kaolinite 

were reported.80 These identifications were based 

partly on petrographic methods and partly on X-ray 

analyses by V. Leinz and O. E. Radczewski.

Glauconite is present in most samples, but it is rare 

and generally forms a very small fraction of 1 percent 

of the sediment. It occurs as tiny pellets that range in 

color from bright green to brownish green. Most of 

this glauconite may have been carried into the ocean 

along with the other clastic constituents, for similar 

glauconite grams were observed in some of the sandy 

limestone and limy sandstone pebbles of the glacial 

marine deposits. However, glauconite grams are 

somewhat more common in cores 12 and 13, and at least 

some of them may have formed in place on the sea floor.

Iron sulphide, the nearly black, probably hydrous 

form, was found in small amounts throughout cores 3 

and 9, but even in these cores it seems to make up only a 

small fraction of 1 percent of the sediment. It commonly 

occurs as aggregates of minute spherules lining the 

borings of small organisms such as worms. Small 

amounts of this iron sulphide also occur in much of 

core 12, but not in the uppermost or lowermost parts. 

It was not found in any of the other cores. A considerable amount of iron oxide coats the clastic grains and 

forammiferal tests in cores 8 and 13, giving the sediment as a whole a rusty-buff color. This brown iron 

oxide was found in parts of some other cores, also, but 

less plentifully. The distribution of the sulphide and 

oxides of iron in the cores suggests that in the deeper 

depressions on the ocean floor, where the finest sediment accumulates in quiet water at a comparatively 

rapid rate, reducing conditions exist and the iron ac-

« Oral communication.

so Oorrens, C. W., Die Sedimente des ftquatorialen Atlantischen Ozeans; Auswertung 

der Ergebnisse: Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, 

Band 3, Teil 3, Lief. 2, pp. 247-248, 263,281-285,1937.

cumulates as the sulphide, whereas on ridges and 

mounds where the water circulates more freely and the 

sediment accumulates more slowly, the iron is converted 

to the oxide. (See the positions of cores 3, 8, 9, and 13 

with respect to the submarine topography in the profile,

%. 1.)

A coating of brownish-black manganese oxide was 

found on some grains of sediment and is particularly 

common on the granules of fine-grained basalt, tachylite, and altered basic glass. As is discussed more fuUy 

on page 32, the volcanic rock penetrated by core 11 

contains a large amount of manganese oxide. The 

MnO soluble in hot dilute hydrochloric acid was determined in the 31 samples listed in table 3 (p. 19) and 

ranges from a trace to a maximum of 0.03 precent. In 

the fusion analyses by Edguigton and By'ers (see'ch. 

on "Selenium content and chemical analyses") the 

MnO ranges from 0.04 to 0.28 percent, but in neither 

series of determinations does the amount of MnO show 

any discernible relationship to the composition or the 

stratigraphic units of the sediments in the cores. 

Correns 81 found that in the Meteor samples the MnO 

varied with the content of CaCO3, but in the Edgington 

and Byers analyses the MnO shows only a random distribution when plotted against the CO2 .

Metallic beads of extra-terrestrial origin, which 

Murray 82 called cosmic spherules, are rare in oceanic 

deposits but somewhat less rare in the red clay. Only 

one minute cosmic spherule was noted in these North 

Atlantic core samples and that only incidentally, as no 

special attempt was made to concentrate these rare 

grains. It had a brilliant metallic luster and the characteristic circular pit. Correns 83 reported only two 

cosmic spherules in the Meteor cores.

SPECTROSCOPIC TESTS

At our request, George Steiger, of the Geological 

Survey, made spectrographic tests for 12 of the less 

common or rare elements whose presence was not 

tested for in any other way in these investigations. 

The samples tested are as follows: W-2 from core 3, 

W-9 from core 5, W-13 from core 8, B-181 from core 

10, B-211 from core 12, and B-232 from core 13. The 

positions of these samples in their respective cores are 

indicated in plate 3. The specimens were tested by 

placing a small portion directly in the carbon arc. 

Each sample gave distinct evidence of barium and 

rather weak evidence of boron. All samples were tested 

for antimony, beryllium, bismuth, cadmium, germanium, lead, silver, tin, and zinc, but if present they were 

in quantities too small to be revealed by n 10-inch 

spectrograph.

si Oorrens, C. W., op. eit., pp. 223-224.

^'Murray, John, and Hjort, Johan, Thp depths of the Ocean, pp. 154-155, London, 

Macmillan Co., 1912.

S3 Correns, C. W., Die Sedimente des aquatorialen Atlantischen Ozeans; Auswertung der Ergebnisse: Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, 

Band 3, Teil 3, Lief. 2, p. 287,1937.
26 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

Goldschmidt and Peters 84 analyzed many substances 

spectrographically and found that igneous rocks are 

generally poor in boron but that sea salts contain 

approximately 0.1 percent and recent marine clays 

contain on the average about 0.03 percent. They 

found that globigerina oozes collected by the Challenger 

contained 0.05 percent. The sediments that Mr. 

Steiger tested for us included both clayey muds and 

globigerina ooze.

POROSITY OF THE SEDIMENTS

The original porosity of some of these sea-bottom 

deposits can be calculated approximately from the 

porosity of the air-dried core and the known amount 

of shrinkage that has occurred upon drying. Because 

the texture and composition of the sediment in core 3 

was nearly homogeneous, samples from it were selected 

for porosity determinations. Fine-grained calcareous 

mud makes up 82 percent of this core. At depths of 

60, 185, and 279 centimeters below the top of the core, 

however, are layers of less calcareous clay, and near the 

bottom there is one thin layer of rather cleanly sorted 

silt. Of the seven samples whose porosity was determined, five (W-l, W-2, W-4, W-5, and W-6) came 

from the calcareous mud and two (W-3 and W-7) 

came from clay layers. The positions of these samples 

are shown in plate 3.

The amount that a wet mud shrinks depends not 

only on the gram size but also upon the size distribution 

and the relative proportions of granular and flakelike 

mineral particles. Uniform shrinkage of a core of 

sediment, therefore, implies uniform physical constitution of the sediment. Core 3 shrank with remarkable uniformity. Exclusive of the clay layers, the 

thin silt layer, and the uppermost piece of the core 

(which is discussed separately below), the dried calcareous mud core has an average width of 4.165 centimeters, but the maximum width is only 0.125 centimeter greater than the average, and the minimum width 

only 0.145 centimeter less than the average. These 

figures are based on 34 measurements. In all the other 

cores the range of differential shrinkage is many times 

greater, except in core 8, which is uniformly coarsegrained. The apparent homogeneity of the calcareous 

mud in core 3 makes it seem well-suited for investigation of the question of whether or not the pore space 

decreases progressively with depth of burial even in 

the uppermost few meters.

Because the sediment may have been compacted 

somewhat as the core barrel was driven into it an 

attempt was made to evaluate this factor before 

computing the original porosity. The experiments recently made by Wrath 85 in cooperation with H. C.

84 Goldschmidt, V. M., and Peters, CL, Zur Geochemie des Bors: Gesell. Wiss. 

Gottinggen, Math.-phys. Kl. Nachr., No. 31, pp. 535-544, 1932.

85 Wrath, W. F., Contamination and compaction in core sampling: Science, vol. 

84, pp. 537-538, 1936.

Stetson at the Woods Hole Oceanographic Institution 

suggest that the sediment in our cores may be considerably compacted, especially in the upper part, as a 

result of friction along the walls of the core barrel. 

Wrath coated the outer surface of the coring tube with 

shellac just before taking each sample and so was 

able to measure the penetration of the tube. In soft 

mud the average length of the recovered cores was a 

little less than 50 percent of the depth of penetration, 

in sandy silt about 50 percent, and in sand nearly 68 

percent. The coring device was a simple weighted 

tube.

Similar results were obtained by the Meteor expedition with a comparable type of core sampler, but after 

they adopted a core bit whose cutting edge had an 

inside diameter a little smaller than the core tube, 

the cores recovered were almost exactly equal in length 

to the distance penetrated by the coring device.86

In the Piggot coring device used to take these North 

Atlantic cores, the inside diameter of the core bit is a 

little smaller than the inside diameter of the barrel 

of the sample tube.87 Judged by the experience reported by the Meteor expedition, this feature should 

have been conducive to the recovery of full-length 

cores. The greater diameter of the sample tube of the 

Piggot sampler (4.9 centimeters as compared with 

2.2 centimeters in the Meteor sample tube) should also 

have reduced the amount of compaction. The core 

bit of the Piggot sampler entered the sediments at 

high velocity and this makes it seem unlikely that much 

water could have been squeezed from so fine grained a 

mud as that in core 3. Then too, the mud core at 

this station is 2.92 meters (9 feet 7 niches) long, which 

is very nearly the full length of the core barrel, 3.05 

meters (10 feet). The device may have penetrated 

32 centimeters more than the full length of the core 

barrel—that is up to the water-exit ports—but it 

seems improbable that it penetrated more deeply than 

that because no mud was found in the water-exit ports, 

where it surely would have lodged if these ports had 

been submerged in mud as they were at station 10. 

(See p. 6.) The sediment in core 3, therefore, may 

have been compacted by the operation of coring as 

much as 14 percent but probably not more than that. 

If the mud was compacted to this degree, the computed 

original porosities may be a few percent too low.

The original porosity of the mud just after the core 

was taken can be calculated from the volume and 

porosity of the dried mud and the volume of the core 

barrel. P. G. Nutting of the Geological Survey 

determined for us the mean grain and lump densities 

and the porosities of seven dried samples from core 3 

and one sample from core 10. These data, together 

with the calculated original porosities, are given in

M Pratje, Otto, Gewinnung und Bearbeitung der Bodenproben: Wiss. Ergeb. 

Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 2, Lief. 1, p. 26, 1935. 

87 Piggot, O. S., oral communication.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 27

table 5. The densities and percent voids refer to 

material dried at 160° C. for 18 hours. The procedure 

used in calculating the porosity is outlined here briefly.

TABLE 5.—Grain and lump density and porosity of dried mud 

from cores 3 and 10, and calculated original porosity

[Data by P. G. Nutting, except calculated original porosity]

Mean grain density. . . 

Mean lump density...

Calculated original

W-l

2.51 

1.23 

51.83

76.4

W-2

2.57 

1.19 

53.76

73.8

W-4

2.51 

1.21 

51. 85

70.2

CoreS

W-5

2.56 

1.23 

51.82

71.6

W-6

2.61 

1.34 

48.64

65.8

W-3

2.59 

1.38 

46.77

76.6

W-7

2.54 

1.47 

42.17

75.6

Core 

10

W-15

2.54 

1.14 

54.97

81.0

The volume of each dried core segment whose original 

porosity was to be calculated was determined as follows: The area of the irregular cross section of half of 

the dried core (A2) was determined by comparing the 

weight of its replica traced on paper with the weight 

of a paper replica of half the cross section of the inside 

of the brass core barrel, the area of which (A^ was calculated. The volume of 1 centimeter length of the 

dried core (V2) is then A2 cubic centimeters. The 

average longitudinal shrinkage per centimeter (Sa) was 

estimated from the average width of the transverse 

cracks that divide the core into segments (in the 

uppermost part of the core the longitudinal shrinkage 

was greater than in the rest of the core (see pi. 2). The 

original undried volume (Vi) of the selected dry sample 

of 1 centimeter in length was therefore (1 cm.+Sa) AI.

The difference between the original volume and the 

volume of the dried segment is the volume of water lost 

in shrinking down to the size of the dried segment. As 

the water occupied the pores in the wet mud, the volume of water lost in that shrinkage equals the volume 

of pore space lost. Then the total volume of pore space 

or voids in the original wet mud was the volume of the 

water lost in drying down to the size of the dried segment plus the pore space (P) of the dried segment. 

The percentage of pores, or the porosity, of the original

wet mud therefore was —

The calculated original porosities for samples W-3, 

W-4, and W-7 are somewhat less reliable than the 

others because the area of the cross section of the dried 

samples was calculated from the diameter of the dried 

segment and an assumed semicircular outline rather 

than a traced outline.

In figure 8 the calculated original porosities of the 

samples from core 3 (W-l to W-7) are plotted against 

the distance below the top of the core. The decrease 

in porosity with depth for the calcareous mud is fairly 

regular, but the calculated porosities for samples W-3 

and W-7 suggest that the clay is compacted less rapidly 

than the calcareous mud. The amount of total carbonate shown in plate 3 for sample W-3 is greater than

that for sample W-7, which suggests that these two 

clays are not strictly comparable. However, two 

samples are not enough to be significant and, as noted 

above, the calculated original porosities for samples 

W-3, W-4, and W-7 are somewhat less reliable than 

the others.

H. B. Moore 88 in his studies of the Clyde Sea muds 

found that the water content by volume (=porosity) of 

the fresh muds within 2.5 centimeters of the mud 

surface at 17 stations ranged from 50.7 to 84.6 percent 

and averaged 77.1 percent. At a depth of 25 to 27.5 

centimeters the muds at 12 of these same stations

tz 

u 

u

- IOO

UJ

OL

O

O

u.

O 

Q. 

O

H

^ 2OO

O

Id

m

id 

o

£in

Q 3OO

\

\

W-3

(Cla^

W-7

(ClatfW-l 

^

\W-2

\ — V—

\

\,

W-5\

• *

W-4

\ 

\

\ 

— \W-6 r 

\

8O 7O 6O 

ORIGINAL POROSITY IN PERCENT

FIGURE 8.—Relation of calculated original porosity of blue mud in core 3 to depth 

below top of core.

(figures for the other 5 lacking) had an average water 

content of 74.3 percent. These figures are comparable 

with the porosities calculated for the sediment in cores 

3 and 10 (see table 5). Moore 89 found also that the 

water content of the Clyde Sea muds decreased much 

more rapidly in the top 5 or 10 centimeters of the mud 

columns than in the lower parts.

The marked upward narrowing of the dried mud at 

the top of the left half of core 3 (see pi. 2) suggests 

that the sediment at the top of this core was considerably more watery than that lower down. .Although 

the calculated porosities given in figure 8 show that the 

top sample has a greater porosity than in the others, 

it is not so disproportionately large as the marked 

shrinkage of the sample would lead one to expect. The 

sediment at the top of this core, however, apparently 

was modified somewhat after the core was taken. The 

evidence for this modification is shown in figure 9, 

which shows that the right-half of the dried core at

8a Moore, H. B., The muds of the Clyde Sea area, part 3: Marine Biol. Assoc. 

United Kingdom Jour., vol. 17, new ser., pp. 331-332, 1931. 

»«Idem, pp. 333-335.
28 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

the top is as wide as the left-half at the first transverse 

shrinkage crack, 13 centimeters below the top. At 

about 6 centimeters down from the top the two are about 

equal. For these two halves of a core of originally 

homogeneous wet mud to shrink so differently upon 

drying to the shrinkage limit implies that the average 

grain size of the part on the right side is considerably 

coarser than that on the left side. The inference 

seems to be that this core lay with the right half down 

for a considerable time after the core was taken and 

that during that time the coarser and heavier particles 

settled to that side leaving chiefly the finer clayey 

particles in the upper (now left) half of the core. This 

inference is strengthened by the fact that this core 

barrel came up from the sea floor slightly bent, and the

FIGURE 9.—Sketch of the two halves of the top part of core 3 showing differentia1

shrinkage.

bend is such that when the core barrel was placed on 

deck it must have lain so that what is now the bottom 

of either the left or right half of the core barrel was 

down. (See pi. 2.) The average width of the two 

halves of the dried core in this uppermost 13 centimeters is 3.44 centimeters, as compared with 4.17 

centimeters for the average width of this kind of material in the rest of the core, which also suggests that 

this upper part was more watery.

MECHANICAL ANALYSES

The preparation for complete mechanical analysis of 

fine-grained sediments is time-consuming, particularly 

of those which are not in their original wet state. Only 

four samples were analyzed, therefore, but these 

samples were selected so as to represent four types of 

sediment found in these cores. They include a blue 

mud (sample W-2) from core 3; a gravelly foraminiferal

deposit (sample W-13) from the top of the mid-Atlantic 

ridge, core 8; a fine-grained globigerina ooze (sample 

W-17), taken from the anchor flukes at the site of core 

10; and a distinctive clay (sample W-18) like that in 

the upper part of core 10 but taken from the water-exit 

ports of the coring device when core 10 was hauled 

inboard. The coring device buried itself deeply at the 

site of core 10, and an unknown amount of mud passed 

upward through the water-exit ports and was lost. 

Samples W-17 and W-18 had been kept moist but the 

other two were thoroughly air-dried. Unfortunately 

no complete mechanical analysis of a sample of a glacial 

marine deposit was made, but the size distribution of 

sample W-13 is somewhat similar except that this 

sample contains an abundance of Foraminifera, whereas 

the glacial marine deposits probably contain a greater 

quantity of silt-size clastic material.

All the samples contained either sea water or salts 

left from the evaporation of sea water, and they were 

therefore first leached in large volumes of distilled 

water on a steam bath. The sediment was stirred 

frequently, and after long settling the clear water above 

the sediment was siphoned off. This was repeated 

until the leach water showed no reaction for chloride 

with acidulated silver nitrate. The leaching required 

a month or more. Next, enough dilute sodium-oxalate 

solution was added to each sample to bring the whole 

suspension to a concentration of approximately N/100, 

following Krumbein's 90 dispersing procedure. The 

samples were then stirred until the dispersion seemed to 

be at a maximum. Thereafter they were analyzed by 

the pipette method according to the technique outlined 

by Krumbein.91 After the pipette samples had been 

taken, the remainder of each sample was wet-screened 

to obtain the size distribution of the constituents larger 

than would pass a 200-mesh sieve.

The results obtained by Grippenberg 92 indicated that 

better dispersion of the finest particles probably would 

have been obtained if the sea salts had been removed 

by electrodialysis.93 Indeed, better dispersion probably 

would have been obtained had the suspensions been 

analyzed immediately after leaching and before the 

sodium oxalate was added. This was shown by two 

other samples, which were leached and finally brought 

into a high state of dispersion but which quickly coagulated when the sodium oxalate solution was added. 

These samples were discarded. More experimentation 

should have been carried out to find the most effective 

means of dispersing these carbonate-rich sediments, but 

the time available precluded it. In fact, these complete

90 Krumbein, W. C., The dispersion of fine-grained sediments for mechanical analysis: Jour. Sedimentary Petrology, vol. 3, pp. 126-127,1933.

91 Krumbein, W. C., The mechanical analysis of fine-grained sediments: Jour. 

Sedimentary Petrology, vol. 2, pp. 144-146,1932.

92 Grippenberg, Stina, Sediments of the North Baltic and adjoining seas: Fennia, 

vol. 60, No. 3, pp. 60-70, 1934.

93 According to C. S. Ross (personal communication), electrodialysis definitely 

breaks down some clay minerals and is, therefore, not satisfactory for dispersing 

fine-grained sediments.
FART i. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 29

mechanical analyses suffered throughout by reason of 

the press of other work that had to be done simultaneously.

Many minute crystals of calcium oxalate were found 

in most of the pipette samples, although none were 

ever found in the sediment 94 not treated with sodium 

oxalate. After the globigerina ooze (sample W-17) had 

been mechanically analyzed, the fine fraction that had 

passed through a 200-mesh sieve was analyzed for calcium oxalate by K. J. Murata of the Geological Survey 

chemical laboratory. He found that 5 percent by 

weight of this dried material consisted of calcium oxalate. Almost precisely 50 percent of the oxalate that

In presenting the results of these mechanical analyses 

two methods have been used—pyramidal diagrams 

(pi. 6) and cumulative curves (fig. 10). In both, the 

size of particles less than 0.074 millimeter is calculated 

by Stokes law from the settling velocity. The sizes 

shown, therefore, are the sizes of ideal spheres that 

have the same mean density and the same settling 

velocity as those observed; they do not represent the 

true particle size, but they probably approximate it 

closely enough for this purpose. In calculating the 

sizes allowance was made for the mean grain density 

of the particles and the density and viscosity of the 

liquid at the time each pipette sample was taken.

II

I 60

> 

CO

UJ 50 x^

2.pnm. I 0.5 0.25 0.125 0,062 0.031 0.016 0.008 0.004 0.002 0.001 0.0005

DIAMETERS CALCULATED ON ASSUMPTION THAT PARTICLES ARE SPHERES

FIGURE 10.—Cumulative curves showing the size distribution of the organisms and mineral particles in samples representing sediments of four types. W-2, Blue mud (core 

3); W-13, gravelly foraminiferal marl (core 8); W-17, globigerina ooze, and W-18, clay (site of core 10).

had been introduced as sodium oxalate had been precipitated as calcium oxalate. As these calcium oxalate 

crystals are only a few microns across, they are concentrated in the fraction of sediment made up of the 

finest particles, which is correspondingly 5 percent 

heavier than in the original sediment.

The sample of blue mud (W-2) from core 3 was not 

properly dispersed, ajid of the sieved fraction made up 

of grains that range in size from 0.074 to 0.15 millimeter, 45 percent consists of clay aggregates. (See pi. 

6.) The diatoms in this sample were coated with a 

thin film of clay, and clay floes probably account for 

some other irregularities. (jSee fig. 10.)

94 Crystals of both calcium oxalate and citrate were found in the bottom deposits 

of the Weddell Sea by F. A. Bannister (Report on some crystalline components of 

the Weddell Sea deposits: Discovery Repts., vol. 13, pp. 60-69, Cambridge, 1936).

The mean grain densities were determined by P. G. 

Nutting of the Geological Survey.

In the pyramidal diagrams given in plate 6 the 

abcissae represent percentages by weight of each size 

group and the ordinates represent a logarithmic scale 

of the size ranges. Descriptive notes, with some 

estimates of proportions, have been added for each 

block or group of blocks in order to show, at Least in a 

rough way, how the various constituents are distributed 

with respect to size. A few blocks will serve to illustrate how the characteristic features of certain sediments 

are revealed by these diagrams. The graph for sample 

W-13 from the top of the mid-Atlantic ridge shows 

that there is an abundance of sand concentrated in the 

size range 0.15 to 0.30 millimeter and that Forammifera 

are also abundant but that their size range extends
30 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

from 0.074 to 0.6 millimeter. The graph for sample 

W-18 shows a highly anomalous feature for a marine 

mud. Concentrated in the coarse silt range (between 

0.04 and 0.74 millimeter) is an abundance of magnetite, 

augite, labradorite, and basaltic glass. This type of mud 

is discussed more fully on pages 32-34, where a complete 

chemical analysis of a similar sample (W-15) is also 

given. (See also dehydration curve, fig. 6.) Sample 

18 also has a considerable number of coarse sand 

grains and pebbles, the presence of which seems explicable only on the assumption that they were dropped 

from an erratic iceberg that went far beyond the 

normal range of drift ice. (See pi. 1.) Consequently 

this sample is less satisfactory than one taken from 

the core itself, but this particular sample was chosen 

because it had been kept wet and was therefore easier 

to disperse. The mud that makes up the top of core 

10, and is in all other respects identical with sample 

W-18, contains no particles larger than silt size. (See 

the gross mechanical composition as plotted in pi. 3, 

samples B-179 and B-180.) In the graph for sample 

W-17 (the globigerina ooze) the height of the blocks 

spanning the size range 0.001 to 0.003 millimeter should 

be reduced by about 5 percent because, as pointed out 

on page 29, they contain about 5 percent by weight of 

calcium oxalate, which is not a normal constituent of 

the sediment. Probably the other pyramidal diagrams 

should have a similar correction.

The cumulative curves of figure 10 also show that in 

sample W-13 a much larger percentage of the constituents are relatively coarse-grained, whereas in sample 

W-2 the dominant constituents are concentrated in the 

finer silt and clay sizes. These curves are markedly 

irregular, and although some of the irregularities are 

due to faulty dispersion of the sediment and to errors in 

size of the pipette samples, others are clearly due to 

concentrations of various constituents within fairly 

narrow ranges of size. For example, the high hump 

between sizes 0.031 and 0.062 millimeter on the curve 

for sample W-18 reflects the concentration of coarse 

silt-size grains of magnetite, augite, labradorite, and 

basaltic glass, already noted. So also the two humps on 

the curve for sample W-17, one at about 0.150 millimeter and the other between 0.031 and 0.062 millimeter evidently reflect the abundance of foraminiferal 

shells in the two size groups.

BASALTIC PYROCLASTICS AND THEIR ALTERATION

As pointed out earlier in the report, pumiceous fragments and smaller shards of basaltic volcanic glass are 

scattered throughout all the cores, but are somewhat 

more common east of the mid-Atlantic ridge than west 

of it. Rarely do these fragments make up as much as 

1 percent of a sample. Notable exceptions to the general distribution of the basaltic glass are core 3, which 

contains very few pieces, and the unusual basaltic 

mud in core 10, which contains an abundance of basaltic

glass. Although some samples contain more than 

others, this basaltic volcanic glass shows no conspicuous 

concentration either in distinct beds or in zones, as 

does the alkalic volcanic glass.

The basaltic glass generally appears to be homogeneous, is clear in thin slivers, and in transmitted 

light has a brown or greenish-brown color. In reflected light it is almost black. The index of refraction 

of the unaltered glass is between 1.59 and 1.60, and most 

of it is nearer 1.60. Basaltic glass of thig type has been 

named sideromelane by Von Waltershausen.95 According to Peacock and Fuller's terminology,96 the less 

clear and less homogeneous basaltic glass containing 

many microlites would be termed tachylite. Tachylite 

is distinctly less common in these cores, but gradations 

from this type to granules of fine-grained basalt consisting of labradorite, magnetite, augite, and in some, 

olivine were found. Some of the clear basaltic glass 

contains minute phenocrysts of labradorite and augite. 

Larger pieces of the basaltic glass, a few of which are as 

much as a centimeter across, are vesicular and about 

as "frothy" as a pumice formed from more alkalic glass. 

Like the basaltic glass pumice noted by Murray,97 it 

tends to have cavities that are more nearly spherical 

than those in most alkalic glass, which are generally 

elongate.

In many samples the basaltic glass has a thin surface 

film of an alteration product that may be classed under 

the broad term palagonite. (See pi. 7,(7). This 

alteration product shows a considerable variation in 

properties, and although two distinct and common types 

were distinguished in the material studied, both are 

classed here as palagonite. One of these is nearly 

colorless and has a refractive index ranging from 1.49 

to 1.52. The other, probably richer in iron, is yellow 

to amber-colored and its refractive index is much higher, 

ranging from 1.57 to 1.59. In the alteration film on 

some of the basaltic glass these two types of palagonite 

alternate with an agatelike interbanding, and in some 

of these alteration films not only are the two types of 

palagonite interbanded, but with them are equally 

thin laminae consisting of radiate needles of a birefringent mineral, apparently one of the clay minerals or 

possibly a chlorite mineral.

In the samples from core 9 the pieces of basaltic 

glass are generally fresh, with only a few showing very 

thin alteration films of the colorless palagonite that 

has the low index of refraction. The pieces of basaltic 

glass from cores 4, 5, 6, and 7 generally have alteration 

films. Some of these alteration films include both 

types of palagonite, and a few, on the more deeply 

altered pieces, include also laminae of the claylike 

mineral. But in cores 8 and 13 the pieces of basaltic

95 Von Waltershausen, Sartorius, tiber die vulkanische Gesteine in Sicilien und 

Island und ihre submarine TJmbildung, pp. 202-204, Gottingen, 1853.

8« Peacock, M. A., and Fuller, R. E., Chlorophaeite, sideromelane, and palagonite 

from the Columbia River Plateau: Am. Mineralogist, vol. 13, pp. 360-383,1928.

•' Murray, J., and Renard, A. F., Deep-sea deposits, Challenger Rept., p. 296,1891.
PART 1. LITHOLOGY AND GEOLOGIC INTERPRETATIONS 31

glass are most conspicuously altered. Indeed, most of 

the grains and pieces are completely altered or contain only a small central nucleus of the basaltic glass. 

The alteration products in these more completely 

altered fragments are largely palagonite and a clay 

mineral resembling beidellite, but they commonly 

include minute prismatic crystals of a zeolite which, 

according to H. E. Merwin 98 of the Geophysical Laboratory, is probably phillipsite. (See pi.7, A.) Lozengeshaped crystals of an unidentified mineral were also 

found in the alteration product. Some of these minute 

crystals were isolated and submitted to Charles Milton, 

of the Geological Survey's chemical laboratory, who 

reported the following properties:

The refractive indices range from 1.56 to 1.57, optically positive, strong dispersion both of bisectrices and 

optic axes (p>v). The crystals are flat, tabular parallel to 010 and have good development of 100, 201, 

and 001. The optic angle is medium-sized, and an 

axis emerges not far from the normal to 010. The 

crystals have excellent basal cleavage, indicating 001. 

The crushed fragments almost invariably show albite 

twinning, the fragments resting on the 001 cleavage; 

Carlsbad twinning was also observed. Good microchemical tests for calcium and aluminum were obtained. 

The crystals are insoluble in HC1 and float in bromoform (density 2.80).

Were it not that these crystals are apparently secondary, that they seem to be very much more fragile 

than feldspars, and that the optic angle is only moderate, they would unhesitatingly be called labradorite.

The degree of alteration of the basaltic glass in 

cores 8 and 13 is obviously greater than in core 9. 

This appears to be significant, as cores 8 and 9 are 

rather close together, and the difference in alteration 

is consistent throughout the length of these two cores. 

The sediment of core 9 evidently accumulated more 

rapidly and under less oxidizing conditions than that 

of cores 8 and 13 (see pp. 14-15), which suggests that 

perhaps the dominant factors in the alteration of basaltic glass on the ocean floor are the amount of oxygen 

in the water and the length of time the particles are 

exposed to the oxidizing water. The relation between 

alteration and oxidation is suggested by the composition of the basaltic glass and of the palagonitic alteration product given by Murray," which show that most 

of the iron was changed from the ferrous to ferric form 

in the alteration from basaltic glass to palagonite. The 

same sort of thing is shown by Correns' analyses 1 of 

the light-brown glass rind of a basalt fragment dredged 

from the mid-Atlantic ridge. The iron determinations,

98 Oral communication.

'9 Murray, John, and Renard, A. F., Deep-sea deposits, Challenger Kept., p. 

307, 1891.

i Correns, C. W., Die Sedimente des aquatorialen Atlantischen Ozeans: Auswertung der Ergebnisse: Wiss. Ergeb. Duetschen Atlantischen Exped. Meteor, 1925-27, 

Band, 3, Teil 3, Lief. 2, pp. 288-289, 1937.

in percent, from the analyses of Murray and Reriard 

and of Correns are given in table 6.

TABLE 6.—Relative oxidation of iron in fresh basaltic glass and in 

basaltic glass altered on the sea floor

FejOs----------- ------------ --------

FeO-..— _—.__—_.—_———_-

Challenger analyses

Fresh 

glass 

(percent)

1.73 

10.92

Altered 

rim 

(percent)

14.57

Meteor analyses

Fresh 

glass 

(percent)

2.30

7.55

-Altered 

rim 

(percent)

16.56 

.93

The oxygen in the bottom waters is derived from the 

cold polar surface water, which sinks in the higher 

latitudes and flows generally equatorward below the 

warmer, and therefore lighter, surface water of the 

middle latitudes. The amount of dissolved oxygen 

that is available for oxidizing particles on the ocean 

floor is therefore a function of the distance i'rom the 

polar seas, the speed of the bottom current, and of the 

environmental conditions of the abyssal organisms that 

consume oxygen. Correns 2 has pointed out that in 

the deep parts of the ocean the constriction in the cross 

section of large, slow-moving currents where they flow 

across ridges on the ocean floor increases their velocity 

enough to winnow out the finest particles and thereby 

increase the proportion of coarse grain-size in the sediments accumulating on the ridges. Thus, in such sites 

where the bottom water moves relatively fast, oxygenrich water is continuously in contact with the sediment, 

and the carbon dioxide formed by oxidation of organic 

matter in the sediment is continually swept away. 

But where the bottom water moves more slowly and in 

places sheltered by ridges, the oxygen content of the 

water close to the bottom decreases, and its carbon 

dioxide content increases. Wattenberg's 3 abundant 

data on the relation between oxygen content and depth 

in the equatorial Atlantic show clearly this oxygen 

diminution within a few hundred meters of the bottom, 

particularly in the western Atlantic.

On the other hand, not all the alteration of the 

basaltic glass occurred while the glass was exposed on 

the sea floor. Some of the alteration was a diagenetic 

change that occurred after the glass was buried in the 

sediment, as is indicated by a piece of vesicular basaltic 

glass from the lower part of core 5. This p^iece of 

basaltic glass scoria, which was nearly a centimeter in 

diameter, was embedded in a foraminiferal marl. The 

glass had a thin surficial film of the colorless palagonitic 

material of low refractive index, and a zone of the sediment surrounding the glass was stained buff with iron 

oxide. This stain faded out rather abruptly in all 

directions away from the nucleus of basaltic scoria.

2 Correns, C. W., Anzeichen von Beziehungen zwischen Stromungei und Bildung 

kiistenferner (eupelagischer) Sedimente: Neues Jahrb., Beilage-Band 57, Abt. A., 

pp. 1109-1117,1928.

3 Wattenberg, H., Die deutsche atlantische Exped. Meteor; Bericht iiber die 

chemischen Arbeiten: Gesell. Erdkunde Berlin Zeitschr., pp. 309-314, 1927.
32 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

The depth of alteration and the variety of alteration 

products derived from the basaltic glass contrast 

sharply with the freshness of the alkalic volcanic glass 

in the upper and lower ash zones of these cores.

VOLCANIC ROCK IN CORE 11

Core 11 represents only 34 centimeters of the sea 

floor because of the hard rock encountered at this depth. 

The hardest rock at the base of this core is an olivine 

basalt, according to Dr. H. E. Merwin,4 of the Geophysical Laboratory, who examined a thin section of it. 

The upper 15 centimeters of the core is a globigerina 

ooze, which rests on and within irregular cavities of 

the upper surface of a clayey rock illustrated in plate 

7, B. This clayey rock grades downward through 

closely similar rock that is strongly impregnated with 

manganese oxide and that contains nodular lumps of 

much altered basalt. Below the manganiferous part 

the clayey rock grades into the hard, more nearly 

fresh basalt at the base. The lower part of this core is 

described in some detail because it suggests that the 

material represents an altered rock which may be a 

submarine lava flow, though the evidence is inadequate 

and additional cores in that area are necessary to test 

this possibility.

The material immediately beneath the globigerina 

ooze (see pi. 7, B) is composed largely of a clay mineral 

resembling beidellite. Within this clay are scattered 

grains of more or less rounded sand and foraminiferal 

shells. The Foraminifera include globigerinas and other 

calcareous types like those that occur in the overlying 

ooze, but their original calcium carbonate tests have 

been replaced by a zeolite resembling phillipsite. 

(See pi. 7, (7.) Some of the lozenge-shaped crystals of 

the unidentified mineral described on page 31 are also 

present in the clay matrix. In places this clay matrix 

contains brown films that outline "ghost" areas of 

shapes resembling shards and pumiceous fragments. 

The similarity of this clayey rock in form and mineral 

composition to the small altered fragments of basaltic 

glass in cores 8 and 13 suggests that this clayey part of 

the rock is altered basaltic glass. The gradation downward from clay that has a vesicular upper surface 

(see pi. 7, B) through manganese-stained clay that 

contains lumps of deeply altered basalt into comparatively fresh olivine basalt at the base suggest the possibility of a submarine lava flow which, in moving over 

the bottom, incorporated some of the sand, Foraminifera, 

and other bottom sediments in its more brecciated and 

apparently glassy surface part. The alteration of this 

glassy surface part is obviously much more complete 

and deep than the alteration rims of the small fragments 

of basic volcanic rock scattered through the sediment 

of the other cores. The greater depth of alteration of 

this rock may have been due to the heat supplied by a

4 Oral communication.

large mass of lava. This heat may also have accounted 

for the replacement of the calcium carbonate of the 

foraminiferal tests by the zeolite—a reaetion not found 

elsewhere in these sediments. Much of the manganese 

in the lower part of this core is in the form of small, 

ellipsoidal pellets separated more or less distinctly 

from one another by thin lenses or irregular layers of 

clay-like material. This is very closely similar to the 

manganese-impregnated zone around the basalt pieces 

dredged by the Discovery from the Carlsberg Ridge.6 

The presence of hard and nearly unaltered basalt at the 

base of this core would not necessarily indicate that all 

the brecciated and altered zone of the supposed flow 

rock had been penetrated, for this fresh rock may be 

only a larger and therefore not completely altered 

fragment similar to the smaller, more deeply altered, 

but nevertheless crystalline lumps of basalt in the clay 

matrix above.

If this rock in core 11 represents an unusually large 

boulder of basaltic rock of ice-rafted origin, it must 

have been altered after it reached the sea floor, because 

the soft, clayey zone of altered material could hardly 

have been preserved during the plucking and transportation by ice. If it is a transported boulder whose 

alteration occurred on the sea floor, it is peculiar that 

the alteration should be so much more extensive than 

is found on the small pieces of basaltic glass and other 

basic rock scattered through the cores; furthermore, 

such a hypothesis would leave quite unexplained the 

conversion of the tests of pelagic Foraminifera to the 

zeolite. The possibility that the rock represents a 

volcanic island which subsided so recently that only 

15 centimeters of globigerina ooze has accumulated on 

it seems rather improbable and also leaves unexplained 

the type of alteration and the replacement of the tests 

of the pelagic Foraminifera.

The globigerina ooze overlying the altered volcanic 

rock in core 11 does not contain shards of alkalic 

volcanic glass of the upper ash zone, as do the tops of 

all the other cores. This absence of shards may not 

be of much significance, for in the other cores the shards 

decrease in abundance upward and are rather sparse 

at the top. On the other hand, the absence of shards 

from the upper part of core 11 might mean that a submarine lava flow had been extruded on the sea floor 

above the upper ash zone, which it covered and partly 

incorporated. According to this hypothesis, no ashbearing sediment is accessible so that it can be reworked 

into the uppermost layer of globigerina ooze.

BASALTIC MUD IN CORE 10

The sediment in core 10 differs from all the others by 

reason of a large proportion of highly distinctive clayey 

mud. As noted on page 6, the coring device buried 

itself in the soft mud at this station. From the glo6 Wiseman, J. D. H., Basalts from the Carlsberg Ridge, Indian Ocean: British Mus. 

(Nat. Hist.), John Murray Exped., Sci. Kept., vol. 3, No. 1, pp. 4-5, fig. 2-A, 1937.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 5

A. FECAL PELLETS OR FILLED BORINGS IN THE BASALTIC MUD AT THE TOP OF CORE 10. SAMPLE B-179.

B. FECAL PELLETS IN MUDDY FORAMINIFERAL MARL NEAR THE TOP OF CORE 12.

Some of the long tubular bodies may perhaps be filled borings. The large, irregular, roundish pellets or lumps are rather common in the glacial marine deposits, but their origin

is unknown. Sample B-207. N

GEOLOGICAL SURVEY PROFESSIONAL PAPER 19fl PLATE fi

SAMPLE W-2

Core 3 

Percentage by weight

SAMPLE W-13

CoreS 

Percentage by weight

Foraminifera, pelagic, 97 percent; sponge 

spicules and tacnylite, 3 percent.

Foraminifera, mostly pelagic, 50 percent. 

Clay floeules, 45 percent. Sponge 

spicules, diatoms, and Eadiolaria, 

.5 percent.

Foraminifera, silt, clay, eoeeoliths, 

sponge spicules, diatoms, calcite particles, and secondary crystals.

Few Foraminifera, silt, clay, coccoliths, 

spicules, and carbonate particles.

Predominantly coccoliths; some silt, 

clay, and fine carbonate particles.

Predominantly coccoliths; some clay 

and considerable finely divided -calcite 

particles of indeterminate origin.

Many coccoliths and carbonate particles 

and clay.

Few coecoliths; mostly clay and indeterminate carbonate particles.

Coccoliths rare and very small; chfefly 

clay and finely divided carbonate 

particles of indeterminate origin.

0.004

0002

OOOI

Pebbles of limestone, quartz, granite, 1 

and other rock types. 1

Grains of limestone and other rock T 

types, quartz, and a few large Fora- 1 

minifera.

Foraminifera, mostly pelagic, about 80 

percent; remainder grains of sand and 

few large diatoms.

nifera, 2§ pe jcen t.

percent; sand 2 percent.

Calcite the dominant constituent; in- j 

eludes fragments of Foraminifera and I 

a few coccoliths but predominantly I 

fine particles of calcite of indetermi- 1 

nate origin. m 

Noncalcareous constituents include 

silt-size particles of many minerals and 

clay.

1

-

i t

SAMPLE W-17 

Taken from anchor flukes 

at core station 10

Percentage by weight 

O 10 *2Q.

025

0.062

0.004

aooz

0,001

Foraminifera, chiefly pelagic.

Foraminifera, chiefly pelagic.

Foraminifera and a relatively small percentage of large diatoms.

Calcareous constituents, 75 percent. 

Foraminifera and recognizable fragments of Foraminifera constitute 20 to 

25 percent; these include many very 

small, probably immature, forms 0.02 

to 0.05 mm. in diameter. Coccoliths 

constitute 15 to 20 percent. Remainder of calcareous part consists of particles of calcite df various shapes and 

sizes but of indeterminate origin.

Noncalcareous constituents, 25 percent, including diatoms, sponge spicules, Radiolaria, and clay.

- SAMPLE.W-ltf 

Taken from water ««it ports 

of sampler at core station IO 

Percentage by weight 

O 6IO 7 *20

05

0,125

0062

Q03(

0016

0.008

0004

0.002

OOOI

0.0005

Pebbles of limestone, shale, and clay- 1 

atotie. 1

Granules of limestone, mudstone, ||l| 

quartz, and tachylite. 1

Foraminifera, mostly pelagic, about 50 LI 

percent; remainder grains of mud- 1 

stone, limestone, tachylite, quartz, 1 

and feldspar. j |

Foraminifera, mostly pelagic, about 95 I 

percent; remainder grains of tachylite [j 

with few floes of clay and grains of 

quartz and feldspar. jS?

Foraminifera, mostly pelagic, about 50 1 

percent; remainder grains of quartz, 11 

calcite, and basal tic and alkalic glass. II

1

Predominantly grains of magnetite, 

augite, labrsdorite, and basaltic glass.

Predominantly nearly pure clay of 

beidellite type mixed with a moderate 

amount of finely divided carbonate

dorite, and basaltic glass constitute 20 

to 25 percent.

-r 1

I

,

20

8

'•o g

as « 

<

V) "i

o

0.25 p 

QC

2

OJ25 J 

K

Z 

O

0.062 £

S 

tf)

> ot b >oc

g i1« 

CALCULATED ETERS, ON

3

, s

iI ETERS.H

< 

a

OBOCA

STANDARD PYRAMID DIAGRAM SHOWING THE SIZE DISTRIBUTION, KINDS OF ORGANISMS, AND MINERAL PARTICLES IN SEDIMENTS OF FOUR TYPES FROM THE NORTH ATLANTIC.

Sample W-2, blue mud from core 3; sample W-13. a gravelly foraminiferal marl from core 8, top of mid-Atlantic ridge; sample W-17, a fine-grained glohigerina ooze taken from anchor lake* at rite of core 10; sample W-18, a diatinctive clay Dice that io the upper part of core 10, takeo from water-exit ports of

coring device when core 10 was hauled aboard. 

228324—40 (Face p. 32)

GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 7

B. VESICULAR UPPER SURFACE OF CLAYEY ROCK 

THAT IS INTERPRETED AS AN ALTERATION 

PRODUCT OF THE BASALTIC LAVA AT THE 

BOTTOM OF CORE 11.

The surface of this clayey rock appears to have retained the 

vesicular form of a lava.

A. ZEOLITE CRYSTALS (a) PROBABLY PHILLIPSITE, IN THIN SECTION OF THE CLAYEY ROCK 

SHOWN IN 7, B.

C. PALAGONITE RIMS SURROUNDING FRAGMENTS OF I l\- 

ALTERED BASALTIC GLASS.

Basaltic glass at a. Delicate concentric banding within the palagonite 

rims is visible at b.

I). FORAMINIFERA SHELLS REPLACED BY A ZEOLITE RESEMBLING PHILLIPSITE.

These are embedded in the clayey rock shown in 7, B.

PAET 1. LITHOLOGY AND GEOLOGIC INTEKPRETATIONS 33

bigerina ooze collected from the anchor flukes we know 

that the floor of the sea is covered with normal globigerina ooze, and from the presence of mud in the waterexit ports 32 centimeters above the top of the core we 

know that the peculiar mud at the top of the core was 

at least a little thicker than is represented in the core. 

Approximately 1 meter at the bottom of this core and 

80 centimeters at the top consist of the distinctive 

mud—a homogeneous, dark-gray sediment that shrank 

greatly upon drying. (See pi. 2.) Although about 50 

percent of this mud is made up of silt-sized particles of 

basaltic glass, magnetite, augite, and calcic plagioclase, 

it contains but little quartz sand or other common 

clastic material, and exceedingly few Foraminifera. 

The remainder of this mud consists predominantly of 

clay minerals resembling beidellite or hydromica. The 

distribution of these constituents is shown hi the diagram, plate 6 (sample W-18), which is based on a complete mechanical analysis of this same type of mud that 

was collected from the water-exit ports of the coring 

device. As noted on page 30, however, that particular 

sample was abnormal because it contained some coarse 

sand and pebbles.

A few normal and common types of pelagic and 

bottom-dwelling Foraminifera were found in the uppermost part of core 10 (sample H-95). In sample W-18, 

which came from the water-exit ports of the coring 

device, above the top of the core, pelagic Foraminifera 

are rather common (see pi. 6), but, as Foraminifera are 

virtually absent from the lower part of the upper clayey 

mud zone and increase in abundance at the top, it is 

suggested that this mud may grade upward into the 

overlying globigerina ooze, just as the lower clayey mud 

zone grades into the foraminiferal marl between the 

mud zones. The basal part of the upper mud zone 

(B-182) is somewhat more silty and has a sharp contact with the underlying foraminiferal marl. (See pL 2.)

A sample of this basaltic mud (W-15), taken 67 centimeters below the top of core 10, was analyzed by E. T. 

Erickson in the chemical laboratory of the Geological 

Survey. Before analysis this sample was leached of: 

its sea salts in distilled water, as is shown by the small 

amount of Cl reported. This analysis is given here as 

reported and also recalculated to 100 percent without 

calcium-magnesium carbonate. In this recalculation 

it was assumed that all the carbon dioxide was present 

in the form of carbonates and that the CaO and MgO 

were combined with it in the same proportions that 

they were found to be present in the fraction of the 

sample soluble in hot dilute HCL This analysis was 

recalculated on a carbonate-free basis so as to compare 

it with analyses of other sediments on a carbonate-free 

basis. The analysis of this basaltic mud is not much 

like those of the common sediments, shale, mudstone, 

or clay; nor, on the other hand, is it like the analyses of 

basalt. It is surprisingly similar, however, to the analysis of a large group of oceanic red clays, despite the

228324°—40——4

SiO2——— ——————————————— ——

AlaOs------- --------- -—— - -.- __ - _ ---

FeO . .

MnOs-. --------------- __ ------ ---------

MgO--————————— ————————

CaO—— —— ———————————————

NajO

KaO . - .- .

HsO-————— —— ———— —— —— — ———— TT"O4-

Ti02— ———— —— —————————————

CO2 - - - -

P2 05— —— — —— ———— —— — —— —— ——

SO3—— —— ——————————————————

Cl - -

A

44.14

12.44

5.74

3.22

Not det.

3.94

10.32

1.31

2.19

3.66

5.48

1.52

6.28

.05

.12

.02

Not det.

100.43

B

52.27

14.73

6.80

3.81

2.05

2.76

1.55

2.59

4.33

6.49

1.80

.06

.14

.02

100.00

C

54.48

15.94

8.66

.84

1.21

3.31

1.96

2.05

2.85

* . Lrt

.98

.30

.38

100.00

fact that the basaltic mud is quite unlike the red clays 

in appearance and mineral composition. (See table 7, 

B and C.) The most striking difference between these 

two analyses is the state of oxidation of the iron. More 

than half the iron in the mud from core 10 is in the 

ferrous state, whereas less than one tenth of that in the 

red clays is ferrous iron.

TABLE 7.—Analyses of mud from core 10 (Sample W~15) and 

oceanic red clays

A. Sample taken 67 centimeters below top of core. Analysed by E. T. Erickson. 

B. Analysis A recalculated as free from CaCOs, MgCO3 .

C. Composite of fifty-one samples of "red clay." Analyzed by G. Steiger, with special determinations by W. F. Hillebrand and E. C. Sullivan.

Although the chemical composition of the basaltic 

mud in core 10 is similar to that of the red clays we 

believe the basaltic mud probably had a quite different 

origin and history. The abundance of basaltic minerals and fresh basaltic glass points to a volcanic source, 

and the extreme scarcity of Foraminifera and coccoliths 

suggests deposition so rapid that they were masked out 

by the bulk of the other material.

Basaltic particles comparable with those found in the 

basaltic mud zones of core 10 presumably were discharged into the water of the Mediterranean over the 

Nerita Bank off the coast of Sicily during the submarine 

eruption of 1831, for according to Washington's 6 

account "* * * the surface of the sea was seen to 

rise to a height of 80 ieet, the column maintaining itself 

for 10 minutes, and then again sinking down. This-was 

repeated every quarter to half an hour, and was accotftpanied by a dense cloud of black smoke and loud 

rumblings." The black smoke presumably consisted of 

basaltic dust particles.

It is perhaps futile to speculate further upon the 

possible origin of the volcanic muds in core 10. Nevertheless, the basaltic composition, the restriction to core 

10, and the fact that the upper mud zone has, at least 

approximately, the same stratigraphic position as the 

volcanic rock in core 11 suggests a genetic relationship 

with deeply altered volcanic rock like that found in 

core 11.

The clay particles and basaltic grains in the greater 

part of this upper mud zone make up a homogeneous

6 Washington, H. S., The submarine eruptions of 1831 and 1891 near Pantelleria: 

Am. Jour. ScL, 4th ser., vol. 27, pp. 133-134, 1909.
34 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

mixture in which there is no discernible tendency 

(other than the comparatively thin basal silty layer) 

toward size gradation according to different settling 

velocities. This suggests that the bulk of the material 

did not settle at the site of this core from a cloud of 

particles thrown into suspension. Had the material 

been diffused upward even a few meters in such a suspension, most of the dense, silt-sized mineral and glass 

particles would have settled out from the cloud of 

minute particles of flaky clay minerals. A submarine 

volcanic eruption, perhaps in the vicinity of core 11, 

may have discharged into the sea finely divided basaltic 

particles and at the same time have thrown into suspension much clay, derived largely from the deeply 

altered surface of earlier submarine lava flows. Such 

a mixture of material, having settled to the bottom, 

would, by reason of its fine grain, make a quite labile 

sediment that would tend to collect in the deeper 

depressions or areas on the sea floor. It might move 

into these lower places either as mud flows on gentle 

slopes or by reworking under the influence of bottom 

currents, perhaps set up by the eruption. The homogeneity of the basaltic mud zones in core 10, with the 

sharply defined base (of the upper one) and gradational

upper parts, suggests that most of the material reached 

its present site as mud flows and that mud-feeding 

animals reworked the uppermost material long thereafter, so that it grades upward into the overlying 

sediment. That mud-feeding animals were effective 

in reworking the upper part of the basaltic mud is 

indicated by the abundance of coprolitic pellets and 

mud-filled borings in the mud at the top of core 10. 

(See pi. 5, A)

Additional cores in the part of the North Atlantic 

where cores 10, 11, and 12 were taken should prove to 

be of exceptional interest, for it is only in this way 

that submarine volcanic activity and its extent can be 

definitely established. Such information might also 

reveal the time of the postulated volcanic activity 

and perhaps, as suggested on page 7, relate it to 

foundering of a part of the Thulean basaltic province, 

which includes part of northwestern Scotland, northern 

Ireland, Iceland, Jan Mayen, and southwestern Greenland.

As with so many phases of this work, only with 

additional and longer cores can the questions raised 

in this investigation be satisfactorily answered.
PART 2. FOEAMINIFERA

By JOSEPH A. CUSHMAN and LLOYD G. HENBEST

PREPARATION OF SAMPLES

The procedure followed in sampling the cores from 

the North Atlantic was essentially the same as that 

described in the report on a deep-sea core coUected in 

1935 southeast of New York City.1 The cores were 

split longitudinally into two parts and allowed to dry 

before they were sampled. With drying, most of the 

sediments became hard enough to be handled more or 

less like indurated rock, so that it was possible to remove with a hacksaw segments from any part of a core 

desired. Several of the globigerina oozes, however, 

remained friable, and required a different method of 

sampling.

At the outset it was decided that to examine thoroughly every centimeter of the cores would require 

more time and assistance than we could devote to this 

study; so, it was necessary either to take long samples 

and thereby run the risk of combining different facies, 

or to take short but representative samples from every 

lithologic zone. Inasmuch as such zones were recognizable by differences in texture, color, composition, 

manner of contracting on drying, or other peculiarities, 

the latter plan was not only feasible but gave opportunity to obtain data that are more significant. In 

addition to some supplementary sampling for studies 

not recorded separately, 184 samples were taken from 

the cores. These are indicated as the "H" series of 

samples, except three which are indicated as belonging 

to the "B" series.

To avoid contamination, constant care was exercisjed 

in ah1 operations. : Each zone of friable sediment was 

cleared as far as possible of extraneous material, and 

the sample was scooped out with a small spoon shaped 

from thin sheet iron. The difficulty of avoiding contamination can easily be appreciated, yet it is almost 

certain that whatever contamination existed was insufficient to change the results of the paleontologic 

studies. Fortunately, only a few zones of very friable 

sediment were encountered. Most of the sediment was 

hard enough after drying to be handled and to withstand without breakage the trimming away of the thin 

layers of dragged material that were formed on the 

outside of the core by the core barrel and through the 

center of the core by the band saw used for splitting

1 Cushman, J. A., Henbest, L. G., and Lohman, K. E., Notes on a core sample 

from the Atlantic Ocean bottom southeast of New York City: Geol. Soc. America 

Bull., vol. 48, p. 1298, 1937.

the cores. Generally it was easy to distinguish the 

layer of extraneous material from the undisturbed 

sediment. The zone of drag on the outside of the cores 

was, in most places, only 2 to 4 millimeters deep, but 

locally this depth was increased by the presence of 

pebbles.

The samples were very carefully washed through 

200-mesh bolting silk, constant care being taken to 

avoid contamination. After drying, each sample was 

searched for metazoan fossils as well as for unusual 

foraminifers and lithologic specimens. The sample was 

then divided and about three-fifths of it, along with foraminifers that were picked out during the search for 

metazoan fossils, was sent to the Cushman Laboratory, 

where Miss Frances L. Parker thoroughly searched the 

samples for Fora minifera and arranged and mounted

the specimens.

ACKNOWLEDGMENTS

The samples were washed by F. S. MacNeil of the 

Geological Survey. The authors are especially indebted to Miss Frances L. Parker of, the Cushman 

Laboratory, who searched the samples for Foraminifera end made a preliminary classification of the 

specimens, and to W. H. Bradley of the Geological 

Survey for a very careful criticism of the text. The 

illustrations on plates 8-10 were drawn by Miss Patricia 

G. Edwards of the Cushman Laboratory. 

DISTRIBUTION IN THE CORES AND LIST OF SPECIES

The species of Foraminifera found in the cores are 

divided into two groups, according as they ar§ of 

pelagic or bottom-living habit, and their distribution 

in each core is plotted on a separate chart. (See figs. 

11-21.) The numbers in the following list of species 

correspond with those appearing on the charts (figs. 

11-21). Some of these Foraminifera listed have not 

been specifically identified, because specific identification would involve considerably more detailed work 

than has been attempted for this paper.

PELAGIC SPECIES

1. Globigerina pachyderma Ehrenberg. (Living habits are not 

definitely known, but despite the fact that it is apparently 

feottom-dwelling during a part if not all of its life history, it has 

been included with the other globigerinids among the pelagic 

forms.)

2. Globigerina bulloides D'Orbigny.

3. Globigerina inflata D'Orbigny.

35
36 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

4. Globorotalia scitula (H. B. Brady). (Not definitely known 

to be pelagic.)

5. Globorotalia hirsuta (D'Orbigny).

6. Globorotalia truncatulinoides (D'Orbigny).

7. Globorotalia menardii (D'Orbigny).

8. Orbulina universa D'Orbigny.

9. Globigerinoides rubra (D'Orbigny).

10. Globigerinoides conglobata (H. B. Brady).

11. Globigerinella aequilateralis (H. B. Brady).

BOTTOM-DWELLING SPECIES

12. Karreriella bradyi (Cushman).

13. Quinqueloculina oblonga (Montagu).

14. Quinqueloculina venusta (Karrer).

15. Massilina tennis (Czjzek).

16. Sigmoilina schlumbergeri A. Silvestri.

17. Triloculina tricarinata D'Orbigny.

18. Pyrgo murrhina (Schwager).

19. Pyrgo serrata (L. W. Bailey).

20. Pyrgo irregularis (D'Orbigny).

21. Ophthalmidium acutimargo (H. B. Brady).

22. Ophthalmidiuminconstans (H. B. Brady).

23. Nonionbarleeanum (Williamson).

24. Nonion pompilioides (Fichtel and Moll).

25. Nonion sp. (?).

26. Bolivinita ?, n. sp. (?).

27. Bulimina aculeata D'Orbigny.

28. Bulimina inflata Seguenza.

29. Bulimina rostrata H. B. Brady.

30. Buliminella elegantissima (D'Orbigny).

31. Virgulina subdepressa H. B. Brady.

32. Virgulina advena Cushman.

33. Virgulina campanulata Egger.

34. Bolivina sp. (?).

3'5. Bolivina subspinescens Cushaman.

36. Uvigerina sp. A.

37. Uvigerina sp. B.

38. Uvigerina sp. C.

39. Uvigerina sp. D.

40. Eponides umbonata (Reuss).

41. Gyroidina soldanii D'Orbigny.

42. Patellina corrugata Williamson.

43. Epistomina elegans (D'Orbigny).

44. Pulvinulinella sp. A.

45. Pulvinulinella sp. B.

46. Cassidulina subglobosa H. B. Brady.

47. Cassidulina crassa D'Orbigny.

48. Cassidulina laevigata D'Orbigny.

FIGURE 11.—Distribution and temperature significance of Foraminifera in core 3.
Bottom-living Foraminifera

FIGURE 12.—Distribution and temperature significance of Foraminifera in core 4.
38 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

FIGURE 13.—Distribution and temperature significance of Foramimfera in core 5.

49. Ehrenbergina serrata Reuss.

50. Chilostomella avoided Reuss.

51. Sphaeroidina bulloides D'Orbigny.

52. Pullenia sphaeroides D'Orbigny.

53. Pullenia quinqueloba (Reuss).

54. Riipertia stabilis Wallich.

55. Laticarinina pauperata (Parker and Jones}

56. Elphidiumsp. (?).

The specimens illustrated on plates 8-10 represent 

the character of the species used in this work for temperature determinations even though their exact nomenclature or classification cannot now be presented. 

The specimens illustrated were taken, wherever possible, 

from the surface or topmost sample of a core.

On the charts (figs. 11-21) the first two columns show 

the number and depth of each sample. The vertical 

length of the sample and its position in centimeters 

below the top of the core are plotted as nearly as possible to scale. Three of the samples have the letter B 

before the number (B-35A in core 4; B-108 and B-109K 

in core 8). All others have prefixed the letter H.

For the pelagic forms a black rectangle indicates

that the particular species is abundant or common; a 

stippled rectangle indicates 6 to 25 specimens; and 1 

to 5 dots in a rectangle represent the exact number of 

specimens found.

For the bottom-dwelling forms a black rectangle 

indicates merely the presence of one or more specimens. 

Not all bottom-living species were plotted, because 

lack of time for an exhaustive study prevented giving 

attention to rare specimens, to species found in only one 

core, or to species that otherwise appeared to have 

little significance. For this reason the relative abundance of bottom-living species was not estimated.

The temperature significance was determined and 

plotted separately for the pelagic and the bottom-living Foramimfera. Relative temperature is indicated 

in the columns headed "warmer" and "colder" by 

large black dots so plotted as to show departures from 

the norm (represented by the vertical line separating 

the two columns), which is based on the temperature 

conditions exhibited by the Foraminifera in the top 

sample of each core and thus represents the present-day 

temperature of the water at that collecting station.
PART 2. FORAMINIFERA 39

FIGUEE 14.—Distribution and temperature significance of Foraminifera in core 6.

PELAGIC FORAMINIFERA

Although the record of foraminifers that have a 

pelagic habit is probably incomplete, enough townet 

samples have been taken from the seas to demonstrate 

that comparatively few genera and species occupy the 

pelagic realm.

The pelagic species of the world belong to the genera 

Globigerina, Globigerinoides, Globigerinella, Orbulina, 

Hastigerina, Hastigerindla, Pulleniatina, Sphaeroidinella, and Candeina, all of which are members of the 

family Globigerinidae, and to the globorotalid genera 

Globotruncana and Globorotalia. Tretomphalus is free 

swimming during the later part of its life but is normally restricted to near-shore or shallow-water areas.

Approximately 26 species of pelagic habit have been 

described. This small number of species and genera 

and their general similarity of shell morphology and 

moderate size may make them appear, from the standpoint of taxonomy, as insignificant members of the 

order Foraminifera, but the principal pelagic species 

produce an enormous number of individuals. They

have been in the first rank of recognizable lime-precipitating agents during and since the middle of the Mesozoic. The small number of pelagic species and their 

comparatively simple taxonomy, their independence of 

local bottom conditions that do not disturb the chemical and physical stratification of the water, and their 

exceptionally broad distribution within their marine 

climatic realms make them a valuable source of information on paleoecology.

All the globigerinids in the core samples except 

Globigerina pachyderma, an Arctic species, are supposed 

to be pelagic. The globigerinids characteristic of very 

warm surface water were not found in abundance in 

the top samples of the cores, but in some of the lower 

zones in several cores warm-water species are present 

in great abundance, thus indicating that at the time 

when the sediments of these zones were deposited the 

Gulf Stream must have extended farther north than it 

does at the present time.

The fauna at the top of each core reflects the temperature of the present time and may, therefore, be
40 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES
Bottom-living Foraminifera

FIGURE 16.—Distribution and temperature significance of Foraminifera in core 8.
42 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES
PART 2. FORAMINIFERA 43

0>

<-: o 

E o

u. >

® 5 Q o

• o>

5-

Pelagic Foraminifera Bottom-living Foraminifera

Core 

No.10

40

O

78- 

86-

IO2-

I 14-- 

127-

139-

154-- 

166-

196-

215- 

223-

241 - 

257-

282-

296 H 112

FIGURE 18.—Distribution and temperature significance of Foraminifera in core 10.

Bottom-living Foraminifera

FIGURE 19.—Distribution and temperature significance of Foraminifera in core 11.
44 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

J3PIOQ

J8WJBM

9joo jo do} M0|8q

LUO Ul L)}d8Q

I I I I I

fs — U) — (0 f)
FIGURE 21.—Distribution and temperature significance of Foraminifera in core 13.
46 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

used as a convenient norm with which the temperatures indicated by the faunas below can be compared 

and plotted. The departures from the temperature 

norms as indicated by the foraminifers have been plotted 

in figures 11 to 21. It is evident from these charts 

that several alternations of periods colder and warmer 

than the present have occurred during the time represented by the sediments in these cores. The zones 

containing Foraminifera of a more tropical or a more 

arctic facies than that represented by the top of the 

core will be referred to respectively as warm or cold, 

whereas those of an intermediate aspect or resembling 

present-day temperatures will be referred to as normal.

Globigerina bulloides D'Orbigny (pi. 8, figs. 2a, b, c.) 

is one of the most generally distributed globigerinids 

in the core samples. It is abundant in all warm and 

normal temperature zones, and though abundant in a 

few of the cold zones it is commonly subordinate, rare, 

or absent in the coldest ones. The distribution of 

this species in the present oceans is somewhat uncertain, because the taxonomic limits of the form are under 

question. Brady and others have considered it almost 

universal, but they may have used too much latitude 

in its taxonomy. In the tropical Atlantic its occurrence 

is spotty, though locally very abundant according to 

Schott.2 Heron-Alien and Earland 3 report it as 

abundant in the New Zealand area and very widely 

distributed elsewhere.

Globigerinoides rubra (D'Orbigny) (pi. 8, fig. 9) is 

extensively distributed in the tropical and warm-temperate waters of the North and South Atlantic, Pacific, 

and Indian Oceans, and in the Mediterranean Sea. 

The species was originally described from the West 

Indies, where it seems to be more prolific and more 

typical than elsewhere. Schott 4 indicates in the 

Meteor report that G. rubra, is one of the more prolific 

species collected in net hauls from the tropical Atlantic. 

In core 3 it is rare throughout and absent from the cold 

zones. It is present in the lower warm zone of core 5 

(H-13). It is rare in samples H-61 (top) and H-72 of 

core 8, rare in 5 samples of core 9, rare in the globigerina 

ooze of core 11, rare in the warmer zones of core 12, and 

absent from ah1 of the other samples.

Globigerinoides conglobata (H. B. Brady) (pi. 8, fig. 

10) is a characteristic tropical Gulf Stream form. 

Brady 5 reports its range in the Atlantic as from latitude 

40° north to 35° south; he found its distribution in the 

Pacific to be more restricted. Later investigators have 

extended somewhat its range in the Pacific region. 

This species was observed in several of the net hauls of 

the Meteor expedition in the tropical Atlantic. It

2 Schott, W., Die Foraminiferen in dem aquatorialen Teil des Atlantischen Ozeans: 

Wiss. Ergeb. Deutschen Atlantischen Exped., Meteor, 1925-27, Band 3, Teil 3, Lief. 

1, pp. 59, 95, etc., 1925.

3 Heron-Alien, Edward, and Earland, Arthur, Foraminifera: British Antarctic 

(Terra Nova) Exped., vol. 6, No. 2, p. 187,1922.

4 Op. cit., pp. 62, 63, 100.

* Brady, H. B., Foraminifera: Challenger Kept., Zoology, vol. 9, p. 603,1884.

appears to be most characteristic and most numerous in 

the tropical part of the Gulf Stream. G. conglobata is 

found sparingly in only the warm zones in core 3, and 

hi the lowest warm zone in cores 5 and 12. Elsewhere, 

it is absent.

Globorotalia menardii (D'Orbigny) (pi. 8, fig. 3) is a 

very prolific species in the pelagic fauna of the tropical 

and temperate waters of the North and South Atlantic. 

It is reported as abundant in the Pacific around the 

Hawaiian and Philippine Islands, where the shells are a 

prominent constituent of the globigerina oozes. It has 

been reported elsewhere in the tropical Indian and 

Pacific Oceans and off the Juan Fernandez Islands. 

Heron-Alien and Earland 6 failed to find the species in 

the Antarctic Ocean, even at stations where preceding 

investigators had reported its occurrence. Brady 7 reports that its northern limit in the Atlantic Ocean is 

55°1 1' north latitude and its southern limit 50° 36' south 

latitude. As now recognized, the species has a worldwide distribution in the tropical and warm-temperate 

zones. G. menardii is present in all samples in core 3, 

except those from two cold zones. Only a few specimens were.found in two moderately cold zones. The 

remaining zones in core 3 are near normal or warmer 

than normal. In core 4 it is present only in the top 

sample. The climate represented by the other samples 

in core 4, as indicated by the pelagic foraminifers, was 

colder than that represented by the top sample. G. 

menardii is absent from the other cores.

In analyzing the significance of the Foraminifera in 

the cores taken by the Meteor, Schott 8 used G. menardii 

as an indicator of surface water temperatures comparable to those now prevailing in the tropical part of the 

Atlantic. G. menardii is a common constituent of the 

globigerina ooze now accumulating in that region. The 

cores taken by the Meteor, however, revealed a zone 

of sediment 20 to 30 centimeters below the sea floor 

that does not contain G. menardii. Schott interpreted 

this zone as representing a period of cold water belonging to the last glacial stage of the Pleistocene. The 

sediment underlying this zone of colder water contains 

G. menardii and was thought by Schott to represent the 

last interglacial epoch.

BOTTOM-LIVING FORAMINIFERA

Information on the distribution of bottom-dwelling 

Foraminifera relative to temperature is less detailed 

and definite than that for the pelagic forms. The 

pelagic foraminiferal faunas are comparatively simple 

in composition, for they contain relatively few but very 

prolific species that generally have a very broad geographic distribution. On the contrary, many bottom6 Heron-Alien, Edward, and Earland, Arthur, Foraminifera: British Antarctic 

(Terra Nova) Exped., vol. 6, No. 2, p. 26,1922.

1 Op. cit., p. 691.

8 Schott, W., Die jungste Vergangenheit des aqua'torialen Atlantischen Ozeans auf 

Grund von Untersuchen an Bodenproben der Meteor Expedition: Naturf. Gesell. 

Rostock Sitzungsber. u. Abh., 3d ser., Band 4, pp. 54-57,1933.
PART 2. FORAMINIFERA 47

dwelling faunas are composed of a large number of 

species whose distribution is variously involved with 

local factors, such as depth, temperature, kind of bottom, intensity of light, and food supply. Although 

existing bottom faunas have been rather extensively 

described, the record of their environment is not yet 

sufficiently definite or comprehensive to be used as the 

basis of ecological determinations with as much assurance as is possible with the pelagic faunas. Nevertheless, the climatic distribution of several bottomliving species is fairly well-known, a few being characteristic of cold water and others of warm water.

The information on the bathymetric distribution of 

the bottom-dwelling Foraminifera is less satisfactory 

than that on climatic distribution. Investigations now 

under way at the Cushman Laboratory in cooperation 

with the Woods Hole Oceanographic Institution promise 

to yield much definitive information, but the studies 

are not sufficiently advanced to apply the results to 

the study of these cores.

Among the enigmatic problems encountered in the 

study of the core faunas is the occurrence in a few unrelated samples of solitary specimens, in part broken or 

worn, of Elphidium or the closely related genus Elphidiella. It seems significant that in nearly all samples 

in which it was found, there was only a single specimen. 

Those found in samples H-74, H-83, and H-133 are in 

zones indicated as warm by other Foraminifera, but 

those found in samples H-5, H-22, H-100, and H-107 

are in zones indicated as colder than normal.

Species of Elphidium and Elphidiella are characteristic of shallow-water, near-shore marine faunas, 

especially in the northern hemisphere, and they have 

been an increasingly prolific constituent of such foraminiferal faunas during and since the Miocene. An 

exception in the North Pacific Ocean has been recorded 

by Cushman 9 and apparently another in the North 

Atlantic Ocean by Cushman, Henbest, and Lohman. 10 

Specimens have been dredged in deep water near Islands 

hi the Pacific, but the eroded shells and the anomalous 

location indicate that they had been transported from 

shallow to deep water. The presence of Elphidium and 

Elphidiella in these deep-sea cores can hardly be construed as evidence for shallow water, because the rarity 

of specimens in our samples, in contrast with their 

great abundance in their normal habitat, suggests 

that they are not indigenous. For these reasons we 

must look for a more satisfactory explanation of their 

presence.

We have not yet encountered a record of Elphidium 

and Elphidiella living as pelagic organisms. The 

records of deep-water dredgings almost uniformly indicate their absence from the abyssal benthos. Trans9 Cushman, J. A., A monograph of the Foraminifera of the North Pacific Ocean: 

, U. S. Nat. Mus. Bull. 71, pt. 4, pp. 30-34, 1914.

10 Cushman, J. A., Henbest, L. G., and Lohman, K. E., Notes on a core sample 

from the Atlantic Ocean bottom southeast of New York City: Geol. Soc. America 

Bull., vol. 48, p. 1304,1937.

portation of shells of these organisms for many hundreds 

of miles by currents on the ocean bottom seems unlikely. Flotation of shells for a few days by gas 

generated in dead sarcode is not entirely improbable, 

though not yet observed or described. However, icebergs and seaweed are transporting agents of great 

capacity and wide distribution and seem to be the most 

likely factors in these and similar problems of erratic 

distribution.

Rafting by icebergs seems possible under conditions 

that would enable the ice to gouge out or incorporate 

and carry shallow-water or littoral sediments. It is 

probably a common occurrence for shallow-water or 

littoral sediments to become incorporated in ground 

ice, shore ice, or the bottoms of grounded icebergs and 

later to be carried to sea when the ice breaks up. At 

least one of the specimens, Elphidiella groenlandica 

(Cushman), known only from the shallow water around 

Greenland (found hi core 5, sample H-5), suggests this 

mode of transportation, because the indigenous Foraminifera in this sample indicate a cold-water environment such as would be expected in areas occupied by 

floating ice.

Seaweed is another important rafting agent. The 

transportation, for example, of near-shore living microorganisms as well as certain larger organisms by sargasso weed broken loose from the West Indies and 

carried to sea by currents is widely known. That mode 

of rafting is by no means restricted to the Sargasso 

Sea.

A similar problem of erratic specimens was encountered among the macrofossils. See chapter on "Miscellaneous fossils and faunal distribution."

Rupertia stabilis Wallich (plate 10, fig. 15) was found 

only in cores 8, 12, and 13, the cores from the shallowest 

water. It is especially common in core 8 and rather 

common in core 13, but in core 12 it was found inxmly 

one sample (H-133). The distribution is about evenly 

divided between warm, medium, and cold zones, thus 

indicating that temperature is not a critical factor in 

its distribution. The absence of this foraminifer from 

the cores taken in deeper water, between cores 8 and 12, 

suggests that depth is an important control. This suggested conclusion is modified, however, by the possibility that the texture of the substrate in cores 9, 10, and 

11 might be a factor as well as depth. In cores 8 and 

13, R. stabilis is found in globigerina ooze of rather 

coarse texture. The ooze in cores 9, 10, and 11 is 

generally finer in texture and contains more clay. If 

depth is a principal control of the distribution of R. 

stabilis, the absence of this species from the cores from 

greater depths in the eastern Atlantic would indicate 

that the ocean level was probably not low enough during the glacial stages to bring the abyssal bottom of the 

region within the depth range of this species. This 

evidence, though indefinite, lends some support to the 

conclusion, originally reached in a study of the other
48 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

invertebrate fossils in the cores, that extreme changes in 

ocean level have not occurred during the time represented by our core samples.

Globigerina pachyderma Ehrenberg (plate 8, figs, la, 

b, c) is of particular interest. Most of the species of 

globigerinids and globorotalids in the core samples are 

exclusively pelagic, except Globigerina pachyderma 

Ehrenberg and possibly Globorotalia scitula (H. B. 

Brady) (plate 8, figs. 5a, b, c). G. pachyderma may be 

pelagic in its early stages, but little is definitely known 

of this aspect of its habits. It is a cold-water form 

originally described from the Davis Straits by Ehrenberg. Brady, 11 Heron-Alien and Earland, 12 and others 

have considered this form as an indicator of cold water. 

Brady states that Globigerina pachyderma is peculiar to 

the high latitudes. Its southernmost range observed in 

the North Atlantic is in the "cold area" in the Faeroe 

Channel at about latitude 60° north. Brady writes 13 

"Within the Arctic Circle it is the most common representative of the genus, occurring sometimes alone 

and sometimes in company with small specimens of 

Globigerina bulloides. I have never succeeded in finding it in tow net gatherings, although small examples 

of the tropical Globigerina bulloides are not uncommon 

amongst the surface organisms of the same areas."

In dredgings from the North Atlantic Ocean, Globigerina pachyderma constantly appears in inverse ratio 

to such pelagic species as Globigerinoides rubra, G. conglobata, and Globorotalia menardii, which are known to 

be characteristic of tropical and warm-temperate surface water like that of the Gulf Stream.

The presence of Globigerina pachyderma or a homeomorph thereof in the Antarctic Ocean was definitely 

established by Heron-Alien and Earland. 14 They 

proposed the idea that this species is a precise 

homeomorph of the true G. pachyderma from the Arctic Ocean and that in the Antarctic Ocean the supposed 

G. pachyderma is a variant of the Arctic species G. dutertrei. If this is true, G. pachyderma is not an example of 

bipolarity, as sometimes supposed. These authors 

agree with Brady's conclusions that the species is probably not, as reported by Murray, 15 a pelagic form.

BATHYMETRIC DISTRIBUTION

In general, the bottom-dwelling Foraminif era are most 

prolific and varied in the cores from the shallowest 

water and least so in those from the deepest water. In 

this respect they exhibit, hi common with the metazoan 

fossils, a bathymetric distribution that is parallel with 

that of marine bottom-living animals of the present 

day. Although the distribution of fossils in the cores 

is treated at greater length in the chapter on "Miscel11 Brady, H. B., Foraminifera: Challenger Kept, vol. 9, p. 600,1884.

12 Heron-Alien, Edward, and Earland, Arthur, Foraminifera: British Antarctic 

Terra Nova Exped., Protozoa, vol. 6, No. 2, pp. 33-36,1922. 

" Brady, H. B., Foraminifera: Challenger Rept., vol. 9, p. 600,1884. 

" Heron-Alien, Edward, and Earland, Arthur, op. cit., pp. 33-36. 

»• Murray, John, The ocean, p. 165, New York, Holt & Co., 1913.

laneous fossils and significance of funal distribution," 

it is appropriate here to direct attention to a few general 

features of the distribution of the Foraminifera.

Cores, 3, 4, and 9 represent rather well the character 

of the foraminiferal population in the cores from the 

deepest water. In these cores the bottom-dweUing 

Foraminifera occupy a very subordinate position in 

number of individuals and include generaUy a smaU 

number of species.

Core 3 contains pelagic foraminifers in aU of the 18 

samples that were extracted but bottom-living forms are 

comparatively rare throughout.

In core 4, 13 samples contain a great abundance of 

pelagic forms; the remaining 6 samples also contain 

them but they are less abundant. In all 19 samples 

the bottom forms are comparatively rare.

In core 9, 4 samples out of 16 contain an abundance 

of pelagic foraminifers; the remainder, with one exception, contain a moderate number. The bottom forms 

are generally subordinate, in some samples very rare 

or absent. In 7 samples, diatoms (mainly Coscinodiscus] compose a large part of the sediment. In one sample of diatom ooze (H-86), bottom-dwelling foraminifers, excepting Globigerina pachyderma, are absent, and 

metazoans are represented only by echinoid spines and 

silica sponge spicules. Shards of alkalic volcanic glass 

are present in large numbers. The pelagic foraminifers indicate cold water.

The core from the shallowest water, No. 8, contains 

not only a large amount of globigerina ooze but also 

a varied and prolific to moderately prolific bottom 

fauna of foraminifers. Throughout this core, the 

pelagic fauna is generally very prolific. Large diatoms 

(Coscinodiscus) and radiolarians were not seen in the 

samples studied for Foraminifera. The bottom fauna, 

both protozoan and metazoan, is more varied and profuse than in the other cores. The core from the next 

shallowest water, No. 13, and the third shaUowest, No. 

12, contain bottom faunas decreasing in variety and 

numbers. The cores from water of intermediate depth 

are intermediate in these aspects of faunal character.

Though relatively pure globigerina oozes are common 

in the cores, as well as those that are more argillaceous 

and arenaceous, shells of bottom-dwelling foraminifers 

are hardly numerous enough in any core to characterize 

the sediment, unless Globigerina pachyderma is included 

among the bottom-living species.

In passing from west to east, core 7 is the first to 

include species of Foraminifera that are European hi 

character. In cores 8 to 13 the character becomes 

increasingly European.

TEMPERATURE INDICATIONS

In attempting to determine the temperature changes 

of the past, the top sample of each core was taken as 

normal, because the top sample represents the present-
PART 2. FORAMINIFEBA 49

day conditions at each collecting locality, except core 

station 10. In core 10 the top sample cannot be taken 

to represent present-day conditions, because the core 

bit penetrated farther than its length into the bottom 

sediment, as indicated by the presence of sediment in 

the water-exit port.

The pelagic and bottom-living Foraminifera were 

studied separately for indications of temperature, and 

the results were plotted separately in figures 11 to 21. 

No attempt was made to express the appraisals in 

terms of degrees, but a relative scale was established for 

each core. The top sample of each core, representing 

the present-day temperature at the collecting locality, 

was taken as the normal. Departures from this norm 

are plotted as warmer or colder, and the apparent extent 

of the departure is indicated on the chart by the distance from the norm. Both positive and negative 

evidence was used in the temperature determinations, 

the absence of known cold-water forms being given a 

certain amount of weight, particularly if such negative 

evidence was supported by absence of cold-water 

species in the samples next above and below.

The temperature changes indicated by the individual 

samples within each core are generally greater than the 

temperature differences similarly indicated as existing 

between the top samples of the different cores. However, a standard or norm of temperature for the whole 

set rather than for individual cores could not be 

attempted at the present time, because factors of depth 

and geographic distribution 16 affect the composition of 

the existing bottom faunas more than temperature alone 

and to a degree probably greater than the difference in 

temperature existing in the area represented by these 

cores. These three major factors are variously concomitant and are only partly separable in fauiial analyses. Of course, it must be admitted that the temperature norms could not be maintained for each individual 

core entirely separate from the others, because the background of previous information on ecology naturally 

tended to introduce a common denominator for the 

entire series.

Though the trends of change are generally similar, 

the pelagic and bottom-dwelling foraminifers do not 

always indicate temperature changes that are exactly 

parallel nor equally divergent from the arbitrary norm. 

This lack of parallelism is to be expected, because extensive chemical and thermal stratification of ocean water 

makes the connection between local climate and the 

bottom layers in abyssal areas more indirect than 

such a connection with the surface layers that are inhabited by the pelagic Foraminifera. Extensive climatic 

changes are probably u. ways accompanied by more or 

less local irregularity. Inasmuch as the temperature 

of the surface water of the North Atlantic Ocean is

w Factors of geographic distribution include the areal pattern of such ecologic controls as submarine topography, chemical composition of the water, bottom conditions, 

turbidity, and food supply that jet limits to migration,

228324°—40——5

controlled at the present time principally by the climate 

of the tropical Atlantic Ocean and Caribbean Sea and 

as the temperature of the bottom layer of water is controlled by the climate of the Arctic region, it would 

seem likely that a lack of parallelism in the climatic 

changes of the tropical and Arctic regions would result 

in a corresponding lack of parallelism in the temperature changes of the surface and bottom layers of water 

of the North Atlantic. It therefore seems more likely 

that the lack of precise parallelism in the temperature 

changes indicated by the Foraminifera were rather a 

result of temporary climatic changes than of broad, 

large-scale geoclimatic changes. The depositional record 

of the Foraminifera does not show annual or short-period 

oscillations.

At the present time, temperature, as well as many 

other ecological factors, usually cannot be interpreted 

on the basis of shell anatomy alone. Some exceptions 

or partial exceptions are known, but no consistently 

workable principles have been discovered. The most 

reliable source of information on the ecology of foraminiferal faunas is still the known distribution of the 

species composing the fauna.

AGE AND CORRELATION

The Foraminifera in the cores are species or varieties 

that have been recorded in existing oceans or in Recent 

and Pleistocene sediments. No Foraminifera known 

to be exclusively characteristic of Pliocene or earlier 

epochs were found. These circumstances set a limit 

to the time span with which we have to deal, but a 

number of difficulties, that are for the present insurmountable, stand in the way of determining precisely 

the age and correlation of the faunas by strictly 

paleontologic methods. One of the principal obstacles 

is that the historical range of the pelagic species 

remains as indefinite, within certain limits, as their 

taxonomy is generalized. Another is that good stratigraphic sequences of beds bearing late Cenozoic to 

Recent Foraminifera are rare and few of these have 

been completely described. This is true not only for 

the Foraminifera enclosed in sediments of epeiric seas, 

from which most marine faunas heretofore available 

to paleontologists are derived, but it is particularly 

true for deep-sea faunas. All the bottom faunas in 

the cores are of a deep-sea facies and therefore belong 

to the group whose history is least known.

The evolutionary and faunal changes in the Foraminifera as a whoJe during and since the Miocene have 

been so gradual that the historical aspect of faunal 

differences cannot be clearly distinguished from the 

complex of existing geographic differences. For example, the shallow-water Foraminifera now living off 

the coast of eastern Florida and those living in the 

abyss at the location of core 12 differ from each other 

more than the Pleistocene Foraminifera at Cornfield
50 GEOLOGY AND BIOLOGY OF NOETH ATLANTIC DEEP-SEA CORES

Harbor, near Point Lookout, Md., 17 differ from those 

now living off the coast of Maryland.

Because of these obstacles, our method of determining 

the age of the faunas and the associated sediments 

was the indirect one of comparing the temperatures 

indicated by the Foraminifera with the physical 

history of the Recent and Pleistocene epochs. The 

faunal differences related to ecology and geographic

" Cushman, J. A., and Cole, W. 8., Pleistocene Foraminifera from Maryland: 

Cushman Lab. Foram. Research Contr., vol. 6, pt. 4, pp. 94-100, pi. 13,1930.

distribution were also obstacles to the direct use of the 

Foraminifera as agents for the detailed correlation of 

horizons from core to core; however, by indicating 

warm and cold periods that were presumably of broad 

geographic extent, the Foraminifera did furnish criteria 

that could be used along with zones of volcanic ash and 

peculiarities of lithology for suggested correlations, 

which have been worked out by Bramlette and 

Bradley. (See pp. 5-7.)
PLATES 8-10

51
	PLATE 8

FIGURE 1. Globigerina pachyderma Ehrenberg. X 90. a, Dorsal view; 6, ventral view; c, peripheral view. Core 3, H-158.

2. Globigerina bulloides D'Orbigny. X 60. a, Dorsal view; b, ventral view; c, peripheral view. Core 4, H-15.

3. Globorotalia menardii (D'Orbigny). X 40. Dorsal view. Core 3, H-166.

4. Globigerina inflaia D'Orbigny. X 60. a, Dorsal view; b, ventral view; c, peripheral view. Core 4, H-15.

5. Globorotalia scitula (H. B. Brady). X 70. a, Dorsal view; b, ventral view; c, peripheral view. Core 4, H-15.

6. Globorotalia hirsuta (D'Orbigny). X 50. a, Dorsal view; b, ventral view; c, peripheral view. Core 3, H-158.

7. Globorotalia truncatulinoides (D'Orbigny). X 50. a, Dorsal view; b, peripheral view. Core 4, H-15.

8. Orbulina universa D'Orbigny. X 33. Core 3, H-158.

9. Globigerinoides rubra (D'Orbigny). X 70. Core 3, H-160.

10. Globigerinoides conglobata (H. B. Brady). X 40. Core 12, H-132.

11. Globigerinella aequilateralis (H. B. Brady). X 50. Core 8, H-78. 

	52
GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 8

PELAGIC FORAMINIFERA FROM THE NORTH ATLANTIC DEEP-SEA CORES.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 9

BOTTOM-LIVING FORAMINIFERA FROM THE NORTH ATLANTIC DEEP-SEA CORES.
PLATE 9

FIGUKES 1, 2. Karreriella bradyi (Cushman). 1, Young stage, X90; 2, adult stage, X 50. Core 7, H-48.

3. Quinquelcculina oblonga (Montagu). X 70. Core 6, H-33.

4. Quinqueloculina venusta Karrer. X 33. Core 5, H-13.

5. Massilina tenuis (Czjzek). X 50. Core 5, H-14.

6. Sigmoilina schlumbergeri A. Silvestri. X 35. Core 7, H-48.

7. Triloculina tricarinata D'Orbigny. X 50. Core 5, H-6.

8. Pyrgo murrhina (Schwager). X 50. Core 4, H-15.

9. Pyrgo serrata (L. W. Bailey). X 33. Core 13, H-142.

10. Pyrgo irregularis (D'Orbigny). X 25. Core 8, H-69.

11. Opthalmidium acidimargo (H. B. Brady). X 65. Core 3, H-158.

12. Opthalmidium inconstans (H. B. Brady). X 50. Core 8, H-71.

13. Nonion barleeanum (Williamson). X 65. a, Side view; b, apertural view. Core 7, H-48.

14. Nonion pompilioides (Fichtel and Moll). X 65. a, Side view; b, apertural view. Core 7, H-48.

15. Nonion sp. (?). X 65. a, Side view; 6, apertural view. Core 12, H-133.

16. Bolivinita (?) sp. (?). X 40. Core 12, H-133a.

17. Bulimina aculeata D'Orbigny. X 40. Core 12, H-133a.

18. Bulimina inflata Seguenza. X 50. Core 13, H-140.

19. Bulimina rostrata H. B. Brady. X 90. Core 4, H-15.

20. Buliminella eleganlissima (D'Orbigny). X 145. Core 3, H-171.

21. Virgulina subdepressa H. B. Brady. X 50. Core 4, H-30.

22. Virgulina advena Cushman. X 50. Core 9, H-89.

23. Virgulina campanulala Egger. X 80. Core 4, H-15. 

24 Bolivina sp. (?). X 90. Core 13, H-145.

25. Bolivina subspinescens Cushman. X 70. Core 5, H—11.

26. Uvigerina sp. A. X 50. Core 5, H-l.

27. Uvigerina sp. B. X 65. Core 5, H-l.

28. Uvigerina sp. C. X 50. Core 13, H-156.

29. Uvigerina sp. D. X 50. Core 12, H-131.

53
PLATE 10

FIGURE 1. Eponides umbonata (Reuss). X 80. a, Dorsal view; b, ventral view; c, peripheral view. Core 3, H-159.

2. Gyroidina soldanii D'Orbigny. X 50. a, Dorsal view; b, ventral view; c, peripheral view. Core 4, H-15.

3. Patellina corrugata Williamson. X 120. Core 8, H-78.

4. Epistomina elegans (D'Orbigny). X 50. a, Dorsal view; b, ventral view; c, peripheral view. Core 7, H-48.

5. Pulvinulinella sp. A. X 90. a, Dorsal view; b, ventral view; c, peripheral view. Core 3, H-158.

6. Pulvinulinella sp. B. X 130. a, Dorsal view; b, ventral view; c, peripheral view. Core 3, H-158.

7. Cassidulina subglobosa H. B. Brady. X 90. Core 5, H-l.

8. Cassidulina laevigata D'Orbigny. X 65. Core 13, H-156.

9. Cassidulina crassa D'Orbigny. X 120. Core 12, H-130.

10. Ehrenbergina serrata Reuss. X 60. Core 5, H-6.

11. Chilostomella ovoidea Reuss. X 70. Core 9, H-79.

12. Sphaeroidina bulloides D'Orbigny. X 130. Core 5, H-l.

13. Pullenia sphaeroides D'Orbigny. X 65. a, Side view; b, apertural view. Core 7, H-48.

14. Pullenia quinqueloba (Reuss). X 70. a, Side view; b, apertural view. Core 13, H-135. f.

15. Rupertia stabilis Wallich. X 25. Core 8, H-69.

16. Laticarinina pauperata (Parker and Jones). X 50. Core 7, H-48. 

54
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 196 PLATE 10

BOTTOM-LIVING FORAMINIFERA FROM THE NORTH ATLANTIC DEEP-SEA CORES.

INDEX

Acknowledgments for aid___________________ ____._ xi, xiv, 2, 35 

aculeata, Bulimina___ _______________ _____________ 36, pi. 9 

aeutimargo, Ophthalmidium___________________________ 36, pi. 9 

advena, Virgulina________________________________ 36, pi. 9 

aequilateralis, Globigerinella________________________ 36, pi. 8 

Age of sediments_ _________________ _ ____________ viii, 49-50

Alkalic glass, occurrence and character of,_______________ 2-3, 32, pi. 3 

Analyses, chemical.._________________________.. x, 1-2,21,31,33 

mechanical,_________________________ viii, 2, 28-30, pis. 3, 6 

Annelids, reworking of sediments by.__.___..________________ 22 

Antevs, Ernst, quoted__ _________________ ______ __ ___ 13

Archeology, significance of core study for......_______________. xiii-xiv

Ash, volcanic, composition and distribution of _________.. vii, 2-3, 22, pis. 3, 4

B

Barium, in sediments___ ____ ______ ____ ___________ viii, 25 

barleeanum, Nonion_____________________________. 36. pi. 9 

Basaltic glass, occurrence and character of _______________ viii, 30-32, pi. 7, C 

Basaltic lava, alteration of_____________________________ 32, pi. 7 

Basaltic mud, in sediments____________ ________ 24-25,32-34, pis. 2,5,6 

Basaltic pyroclastics, character and distribution of ______ __.. ______ 30-32 

Blue mud, accumulation of, rate of _ ________________________ 13

occurrence and character of____________________ 5, 19, 27-29, pi. 6 

Bolivinasp.?____________________________________ 36, pi. 9

subspinescens_________________________________ 36, pi. 9 

Bolivinita?, n. sp.?________________...__.____.______ 36, pi. 9 

Boron, insediments..____________________._____ viii, 25-26 

Bottom currents, evidence of__________________________ vii, 14-15 

Bottom-dwelling species of Foraminifera____________ 36-39, 40-48, pis. 9,10 

Bradley, W. H., introduction by.. __________ _________ ___ xiii-xv

with Bramlette, M. N., Lithology and geologic interpretations___ 1-34, pis. 3-7 

bradyi, Karreriella_________________________________ 36, pi. 9 

Bramlette, M. N., and Bradley, W. H., Lithology and geologic interpretations__________—________.____________ 1-34, pis. 3-7 

Bulimina aculeata__________________________________ 36, pi. 9

inflata._____________________________________. 36, pi. 9

rostrata_____________________________________ 36, pi. 9 

Buliminellaelegantissima- —--__________________________ 36, pi. g 

bulloides, Globigerina___________________________ 35, 46, 48, pi. g

Sphaeroidina___________.______________________ 38, pi. 1.

C

campanulata, Virgulina_____——____.__—___.__.._____.. 36, pi. 9 

Candeina_.___________—————_———___———________ 39 

Carbonate, in sediments________________._____ viii, 17-21, pis. 3, 6 

Carnegie Institution of Washington, work on deep-sea cores by_. _____ vii, xi, xiv . Cassidulina crassa...—„__——.—————————_—————____ 36, pi. 10 

laevigata___________——_._-_—__——.._______ 36, pi. 10 

subglobosa________________________________36, pi. 10 

Chilostomella ovoidea________________.______________ 38, pi. lo 

Clay. See Red clay.

Clay minerals, in sediments.————_———————————————__ 24-25, pis. 3, 6 

Climate, relation of sediments to___________ vii, viii, x, xiii, 8-13, 48-49, pi. 4 

Coccoliths, occurrence and character of.—_———....__.———. 3-4, 14-18, pis. 3, 6 

rate of accumulation of.__——_—————___————________ 13-14 

conglobata, Globigerinoides.. ——...——————__..————..... 36, 46, 48, pi. 8 

Core samples, methods used in obtaining—————...__——___ xiv-xv, 26, 35 

Core stations, location of__...——————————._——————___._ xiv, pi. 1 

Correlation of zones represented in the cores. __._ ____ viii, 5-7, 49-50, pi. 3, 4 

corrugata, Patellina——...——————————————————————————— 36, pi. 10 

Cosmic spherules, occurrence of————————————.——————___..__.. 25 

crassa, Cassidulina——__——————————————————————————— 36, pi. 10 

Crinoids, in sediments...——————————————————————————————_ ix 

Currents, bottom, evidence of...——._——————_——————_____ vii, 14-15 

Cushman, J. A., and Henbest, Lloyd, Foraminifera_________ 35-50, pis. 8-10

Diatomaceae. .__——.—————————————————————————————— viii-ix 

Diatoms, distribution of, in sediments___——..___————__ viii-ix, 14, pi. 6 

dutertrei, Globigerina.._—————————————————————————————— 48

E

Echinodermata....——.————

Echinoids, associations of———

reworking of sediments by. 22

Page

Ehrenbergina serrata_______________________________ 38, pi. 10 

Elasipoda, abundance of__________.______..____________ 22 

elegans, Epistomina____________________________ ___ 36, pi. 10 

elegantissima, Buliminella—___________________________ 36, pi. 9 

Elphidiella______________________________________ viii, 47 

groenlandica.__._—_____________________________ 47 

Elphidium...____________..——_____________________ viii

sp. 38,47

Epistomina elegans. _______________________________ 36, pi. 10 

Eponides umbonata____________________.___ _ ____ 36, pi. 10 

Erickson, E. T., analysis by.__________._______________. 1,21,33

Faraday Hills, features of________.______..._______... xiv, 14, pi. 3 

Faunas, distribution of.______________________________ ix 

Fecal pellets, evidence of, in sediments—._____.._____ viii, 23, pi. 5, A, B 

Foraminifera, age and correlation of______________________ viii, 49-50 

distribution and environmental significance of —————————————.vii-viii,

3-4, 12-13, 16, 17-18, 35-49, pis. 3, 4, 6

list of species of-____________________—_.___—___ 35-36,38

replacement of, by a zeolite____.________.___...——_ 32, pi. 7, D

Foraminiferal marl, meaning of term. _______________ __ __ vii-viii, 17

Fossils, miscellaneous, distribution of______ ______ __________ ix

Foundering of ocean floor, suggested__..______.__-..._.____.. 7

G 

Gastropods, environment of._______._____-......_____.___.. ix

Glacial marine deposits, age of____ . ___________ __________ vii 

borings or fecal pellets in___....—,._._..._——__..—— 23, pis. 5, A, B

distribution and succession of__________________-.--... 7-12, pis. 3, 4 

features of_____________________________ vii, 3-5, 23, pis. 1, 3, 4 

sources of._______________________ _____...____ 7-8

Glass shards, occurrence and character of_ ________ viii, 2-3,30-32, pis. 3,7, C

Globigerina. _____________________________________ 39, pi. 8

bulloides____............................ ——-......——.. 35,46,48, pi. 8

dutertrei_____________.-.._____——..—_—————...—— 48 

inflata________________________________________ 35, pi. 8

pachyderma____________--.....____...___.._... 35,39,48, pi. 8

Globigerina ooze, distribution of.____._____——...——— —...——_. 18

meaning of term____________..____..—___..———... vii-viii, 17

rate of accumulation of. _______.____———_——————_———— 13

Globigerinella_________.___:.___._________..——___ 39, pi. 8

aequilateralis____________________ _.___———___ 36, pi. 8

Globigerinoides.___.__._________.._———.—..——_—— 39, pi. 8

conglobata-..———————————— —————- 36,46,48, pi. 8

rubra_____________________________________ 36,46,48, pi. 8 

Globorotalia—........—.__..-.———————————————— 39, pi. 8

hirsuta———————————————————————— 36, pi. 8

menardii___________________________________ 36,46, pi. 8 

scitula——_...............-——————————...——.——. 36,48, pi. 8

truncatulinoides.__________________________-____ 36, pi. 8 

Globotruncana. ____________....___————————————————— 39

Grain size of sediments__..___..__——___.. viii, 2,15-16, 29-30, pis. 3, 6 

groenlandica, Elphidiella________________—_..————————— 47 

Gyroidina soldanii._________________.__.____——___ 36, pi. 10

H

Hastigerina_______________——_—————————————————— 39 

Hastigerinella.___________________.——————————————— 39 

Henbest, L. G., with Cushman, J. A., Foraminifera_________ 35-50, pis. 8-10 

hirsuta, Globorotalia ...________________—————.———————— 36, pi. 8 

Hjort, J., with Murray, J., quoted___..___——————— — — ———— 15,20,23 

Holothuroidea, reworking of sediments by_____——__————————— 22-23 

Howard, C. S., analyses by______________——.——————————— 2

inconstans, Ophthalmidium____...——_..————————————————— 36, pi. 9

inflata, Bulimina..______________.__.-.—.——. ——————- 36,pi.9

Globigerina......_—————————————_-..—————— 35, pi. 8

Introduction to complete report..————————————————————————— xiii-xv 

irregularis. Pyrgo___——.___——.——.——————————————-—- 36, pi. 9

Karreriella bradyi...————__._-——————..__....———— 36,pl.9

55
56 INDEX

L Page

laevigata, Cassidulina______________. _______________ 36, pi. 10 

Laticarinina pauperata.______________________________ 38, pi. 10 

Lava, basaltic, alteration of____________________________ 32, pi. 7 

Lithologic zones in cores, correlation of________________ vii, 5-7, pis. 2, 3 

Lilhology and geologic interpretations-.____________ vii-viii, 1-34, pis. 3-7 

Location of region studied....._____. ___ _ _____ —______ vii, xi, pi. 1

M

Marl, foraminiferal, meaning of term_ ____________________ vii-viii, 17 

Massilina tenuis___________ _________ ___ __ ________ 36, pi. 9 

Mediterranean Sea, sediments in, significance of-_______________ xiii-xiv

submarine volcanic activity in_________________________ 33 

menardii, Globorotalia_____________________________ 36,46, pi. 8 

Mid-Atlantic ridge, sediments on crest of _ ___________________ 14-15 

Milton, Charles, analysis by_____________________________ 31 

Mineralogy of the clastic sediments_________________________ 23-25 

miranda, Pourtalesia__---_____________________________ ix 

Mollusca._______-_______________________________ ix 

Mud, basaltic.____________________________ 24-25, 32-34, pis. 2, 5,6

blue._——_————.....__————-..—.-. 5, 13, 19, 28, 29, pi. 6 

Mud-feeding organisms, roleof________________________ vii, 22-23,24 

Murray, J., and Hjort, J., quoted________________________ 15,20,23

and Renard, A. F., quoted____..._____________________ 23 

murrhina, Pyrgo__________________________________ 36, pi. 9

N

Nonion barleeanum__—_________________________ __ 36, pi. 9 

pompilionoides_________________________.._____ 36, pi. 9 

sp.?—-.——————_——.........__————————_... 36, pi. 9

O

oblonga, Quinqueloculina_____________________________ 36, pi. 9 

Ophiuroids, associations of______________________________ ix, 22 

Ophthalmidium acutimargo___________________________ 36, pi. 9

inconstans___________________________________ 36, pi. 9 

Orbulina______________________________________ 36, pi. 8

universa___—_——______——________________ 36, pi. 8 

Organic content of sediments...___________________________ ix-x 

Ostracoda_______________________________________ ix 

Outline of complete report______________________________ v 

ovoidea, Chilostomella______________________________ 38, pi. 10 

Oxygen content in ocean water, relation of, to depth_______________ 31

pachyderma, Globigerina_________________________ 35, 39, 48, pi. 8 

Palagonite, character and occurrence of______________ viii, 30-32, pi. 7, C 

Patellina corrugata_ _______________________________ 36, pi. 10 

pauperata, Laticarinina_____________________________ 38, pi. 10 

Peach, B. N., quoted. ________________________________ 15 

Pelagic species of Foraminifera_______________ _______ 35-46,48, pi. 8 

Pelecypods, environment of.________.____________________ ix 

Phillipsite, in sediments___________________________ 31, pi. 7, A 

Piggot, C. S., coring device designed by________ ________ vii, xiv-xv, 26

foreword by..___________________________________ xi-xii 

Plankton, abundance of ____________. ___ _______________ 13

relation of, to organic content__________________________ x 

Pleistocene, stages or substages of, interpretations of glacial marine zones of.. 10-12 

pompilionoides, Nonion______________________________ 36, pi. 9 

Porosity of the sediments___________________________ viii, 26-28 

Pourtalesia miranda__________________________________ ix 

Pteropod shells, distribution of__________________________ viii, ix

significance of ________________________________ 7,15-16,19 

Pullenia quinqueloba_______________________________ 38, pi. 10

sphaeroides... _____________________________ ___ 38, pi. 10 

Pulleniatina______________________________________ 39 

Pulvinulinella sp_________________________________ 36, pi. 10 

Pyrgo irregularis__________________________________ 36, pi. 9

murrhina____________________________________ 36, pi. 9

serrata——.......—.—.„.......———.——.....——..._____ 36, pi. 9

Q

quinqueloba, Pullenia______________________________ 38, pi. 10

Quinqueloculina oblonga._____________________________ 36, pi. 9

venusta.....________________________________ 36, pi. 9

R

Radiolaria, presence of.______________________________ 21, pi. 6 

Radium, concentration of, on ocean bottom______________________ xi 

Bare elements, spectroscopic tests for.___—________________ viii, 25-26

Page

Red clay, analysis of.——————————————————————————————— 33 

rate of accumulation of.————————————————————————————— 13 

Region sampled, extent of______————..———.——————.__ vii, xi, pi. 1 

Renard, A. F., with Hjort, J., quoted_.________——_________ 23 

rostrata, Bulimina____._____—————————.—————————.—— 36, pi. 9 

rubra, Olobigerinoides____________._—__.——..__. 36, 46, 48, pi. 8 

Rupertiastabilis——...——__———..—————.......... 38, 47, pi. 10

S 

Sampling and examination of cores, methods of...------—...—.._ xiv-xv, 26, 35

schlumbergeri, Sigmoilina.-.——————————————————————————— 36, pi. 9 

scitula, Globorotalia.-———_—————.„————......_... 36, 48, pi. 8

Sediments, age and correlation of.._...—————_—————.__ viii, 5-7, 49-50 

carbonate content of________—————_—————————.. 17-21, pi. 3, 6 

grain size of.._________________-__----- viii, 2, 15-16, 29-30, pis. 3. 6

mineralogy of ———————————————————————————————————— 23-25 

organic content of—————————————————————————————————— ix-x 

porosity of—_—__——..—————————————————. 26-28

rate of deposition of___———————————————————————..——— 13-14

siliceous organisms in.—__.__————————————————————.——— 21

sulphates in.. ————————————— ——————————————————— 21

temperature of the ocean as indicated by——————————————————. 8-9

terrigenous material in.——__——————————————————.——... 7-8

Selenium content of sediments———————————————————————————— x

serrata, Ehrenbergina——————————————————————————————— 38, pi. 10

Pyrgo———————————————————————— 36, pi. 9

Shrinkage, differential, in core material—————————————————._——.. 26,28 

Sigmoilina schlumbergeri————_———————————————————————— 36, pi. 9 

Siliceous organisms, remains of..—————————————————————————— 21 

Slumping, evidence of.——————————————————————————————— 7,15-16 

Solar radiation, effects of.——————————————————————————————— 12 

soldanii, Gyroidina.________-_————-——--——-——————— 36, pi. 10 

Spectroscopic tests of sediments-___——————___—————____ viii, 25-26 

sphaeroides, Pullenia-————————————————————————————— 38, pi. 10 

Sphaeroidina bulloides——......———————————————————————— 38, pi. 10

Sphaeroidinella___————————————————————————————————— 39 

Sponge spicules, presence of——......—————————————————————— 21, pi. 6

stabilis, Rupertia...——————————-————.———... 38,47, pi. 10

Steiger, George, analyses by——————————————————————————— 25-26,33 

Stratigraphic units in cores———— —————————————— ————————— 2-5, pi. 3 

subdepresa, Virgulina.——————————————————————————————— 36, pi. 9 

subglobosa, Cassidulina—————————————————————————————— 36, pi. 10 

subspinescens, Bolivina————-————————————————————————— 36, pi. 9 

Sulphates in the sediments.- ——————————————————— ————————— 21 

Summary of complete report—.——————————————————————————— viii-x

T

Tarr, R. S., quoted———————————————————————————————— 4 

Temperature, relation of type of sediment to______ vii, viii, x, 8-13, 36-49, pi. 4 

tenuis, Massilina- __ ___——__————————-———————————— 36, pi. 9 

Texture of sediments, relation of, to organic content..—————————_.—... x 

Thfiel, Hjalmar, quoted.——————————————————————————————— 22 

Tidal currents, evidence of______—————-..._———.———_— vii, 14-15 

Tretomphalus—__————————————————————————————————— 39 

tricarinata, Triloculina——————————————————————————————— 36, pi. 9 

Triloculina tricarinata——_———————————————..——————————— 36, pi. 9 

truncatulinoides, Globorotalia____——————..——————————..—— 36, pi. 8

U

umbonata, Eponides—————_—————————————————————————— 36, pi. 10 

universa, Orbulina-————————————————————————————————— 36, pi. 8 

Uranium, in ocean sediments———————————————————————————— xi 

Uvigerinasp.._—————————————————————————————————— 36,pi. 9

venusta, Quinqueloculina-——————.————————————————————.. 36, pi. 9

Virgulina advena___——_—__————————————————————— 36, pi. 9

campanulata__———————————————————————————————— 36, pi. 9

subdepressa——.——.—..————————————————————————— 36, pi. 9

Volcanic ash, composition and distribution of...___—_—_. vii, 2-3, 22, pis. 3, 4

Volcanic glass, occurrence and character of.________ viii, 2-3, 30-32, pis. 3, 7, C

Volcanic rock, alteration of.__._..——.—————.———————————— 32, pi. 7

W 

Washington, H. S., quoted—.——————————————————————————— 33

Zeolites, occurrence of__________——.__....—————„ 31-32, pi. 7, A,D

replacement of foraminiferal shells by________„________ 32, pi. 7, D

Zones represented in the cores, correlation of- — -.—-_———————— viii, 5-7, pi. 3

O
The use of the subjoined mailing label to return

this report will be official business, and no

postage stamps will be rectuired

UNITED STATES PENALTY FOR PRIVATE USE TO AVOID 

DEPARTMENT OF THE INTERIOR PAYMENT OF POSTAGE. $soo

GEOLOGICAL. SURVEY

OFFICIAL BUSINESS

This label can be used only for returning 

official publications. The address must not 

be changed.

GEOLOGICAL SURVEY,

WASHINGTON, D. C