Antarctic Ocean-Floor Fossils: Their Environments and Possible Significance 
as Indicators of Ice Conditions 1 
Charles W. Thomas 
ABSTRACT: Seven Antarctic marine environments are examined with respect to 
their geology and to the skeletal remains of marine microorganisms. While all 
assemblages live in the same water mass, they vary significantly from place to place. 
Geology and oceanography of each locality appear to produce less effect upon the 
character of populations than do topography and bay ice. The latter features sug- 
gest a possible use of fossils as indicators of conditions of bay ice. 
During the establishment by the U. S. 
Navy of permanent scientific bases in the Ant- 
arctic, from 1955 to 1957, coring and Orange 
Peel sampling of the ocean bottom was car- 
ried out under the general supervision of Dr. 
Willis L. Tressler, Senior Oceanographer as- 
signed to U. S. Naval Task Force 43. This 
subdivision of command was responsible for 
the Navy’s commitment in Antarctica. The 
author of this report was Chief of Staff. 
General areas of ocean-bottom sampling con- 
sidered in this paper are: Ross Barrier, Mc- 
Murdo Sound, Hallett Inlet, Robertson Bay, 
Sabrina Coast, and Knox Coast. During the 
period of this study the Bay of Whales, once 
carved in the Ross Ice Shelf, was not extant, 
having been erased by iceberg-calving some 
time between 1947 and 1954. Since it was not 
possible to carry out sampling there, the Gould 
material, collected from the Bay of Whales in 
1929 and analyzed by Warthin (1934), is 
considered in this paper. 
The region represented in Gould’s sampling 
is from the Bay of Whales to the Knox Coast 
(Clark Peninsula) (Fig. 1). This sector en- 
compasses ca. 2,100 miles of the periphery of 
Antarctica, extending through ca. 90° of longi- 
tude. This continental periphery is washed by 
the Circumpolar Countercurrent, an easterly 
current generated by prevailing winds and di- 
rected by Coriolis force. Surface temperatures 
range from — 1.62°C to — 2.13°C; bottom 
1 Paper presented at the Eleventh Pacific Science 
Congress, Tokyo, 1966. Hawaii Institute of Geo- 
physics Contribution No. 195. Manuscript received 
October 18, 1966. 
temperatures, from — 1.00°C to — 1.85°C. The 
surface current attains velocities as high as 3 
knots (author’s observation). 
THE STATIONS 
Sampling was undertaken at the following 
stations : 
Bay of Whales'. In 1929 (when the Gould 
material was collected), the Bay of Whales 
was an indentation in the Ross Ice Shelf 13 
miles long by 5 miles wide. During its life 
the embayment’s shape and dimensions were 
constantly changing. As far as anyone knows, 
bay ice was swept out of the bay every year. 
Breakup generally occurred in January or Feb- 
ruary when winds produced waves which en- 
tered the bay and cracked the ice. The Gould 
collection of sediments was made at 78°34'S, 
163°48'W in 548 m of water. The outer limits 
of the Ross Ice Shelf are known to fluctuate 
(Thomas, I960) and an embayment (Discovery 
Inlet) once occupied the area where the sam- 
pling was made. However, this location now 
generally features hummocky sea ice during the 
greater part of the year. It is free of fast ice 
during the summer months. 
Arrival Bay : This is a cove in Ross Island 
on the eastern side of McMurdo Sound. It is 
separated from Winter Quarters Bay (where 
Scott’s "Discovery” was frozen in for two 
years) by Hut Point. Ross Island is of Tertiary 
orogeny and consists chiefly of beds of lava 
and tuff. Mt. Erebus, an active volcano, is 
situated on the northwest side and Mt. Terror 
(now extinct) on the northeast side. There 
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