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ostracode fama in these samples to consist of a
mixture of three components representing three
distinct zoogeographic provinces (fig. 94). Tne first
component Is thought to be a shallow-water
assemblage of cold-temperate species from the
Aleutian Province, which extends today Prom near
Vancouver Island to Bristol Bay. Numerous phytal
for ms pon
Paradoxostoma, and
within the photic eone. Several of the cold-temperate
indicator species are known to be living in the Gulf of
Alaska and near the Pribflof Islands.
I ASIA
F@m =-North Pacific Ocean (modified from US.
Navy, Chief of Naval Operations, 19771, showing
modern boundaries of cold-temperate and subfrigid
marine climates. Cold-temperature zone is termed
the Hokkaidan Province in the western Pacific and the
Aleutian Province in the eastern Paciflc; subfrigid
zone is termed the Bering Province. Arrows Indicate
interpreted origins of fossil faunas wcurring In
Aleutian Island samples (fig. 93).
The second component Is represented by species
that are very similar to westwn Pacific faunas from
the cold-temperate Hokkaido Province. The
ostracodes are congeneric wlth ostracode assemblages
ocuurring along Japan and the Kuril Islands (for
example; - ~inharchinella [Barentsovia],
Bythocythetorn~rpha, and Pectocythere). Because so
?ew Quaternary rniorofaunas have been documented
from the western Pacific, it is difficult to determine
whether these forms are conspeclfic.
The third component has a modern distribution in
colder water (subfrlgid to frlgid marine climates) than
ls currently present in the Aleutians. We interpret the
presence of this component to Indtcate that the
thermal regime at the time of deposition of these
species was much colder. Thls colder water fauna has
migrated from the Berlnu and Arctic Provinces of Asia
and Norm America, and ;ncludes the ostracode species
Elofsonella conciha neoconcinna, ~lnrnarchinella
m a ) barentzovoensls, and Eucytherldea
-ic fotaminller.l ~ssernblalru fmm the
Aleutlan Islands samples contaln n;merow fossil
Jpecies as well as cold-temperate species indigenous to
the North Pacifio. EIphidium clavatum is a common
member of thesa assembhges and, in conjunction with
6. bartletti & orbiculare, & subarcticum, and
~ucc-@da, represents the mldarctic fauns
which edsted in this area during the glacial episodes.
The occurrence of Cassidurina californierr, Elphidiella
groanlandlea, and numerous other neritic species
Lndlcates the presenae of cold-temperate Paclfic
faunas. These benthic foraminiferal speaias, like the
cold-temperate ostracode species, are presently living
In the Gulf of Alaska. Agaln, because organia stain
was not used, it Is *own whether these species were
living there at the time of collection.
Thls analysls suggests that: (1) During the
Reiatocene, cold-arctic waters extended as far south
as the Aleutian Islands; and (2) durhg the Holocene,
cold-temperate water masses from the North Paclffc
have extended as far north as the PribhoP Islands.
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