Thule, Bellingshausen, and Cook
islands are the southernmost
volcanoes in the arc. Volcanic
heat keeps the crater on Thule Island
ice free. In 1962, steam was rising
from the water in Thule's summit
crater and ash was noted on the
island's southwest flank. A caldera has
been tenatively identified between the
islands of Thule and Cook, thus these two islands may
be pieces of a larger island that once existed there.
Unlike most of the South Sandwich Islands, where most volcanoes are made of basalt, part of Cook Island is composed of andesite and dacite. Bellingshausen is a small youthful andesite cone with active fumaroles but no historic eruptions.
Sources of Information:
Click here to view the sources used in the South Sandwich Islands section.
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