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Compositions of Igneous Rocks in the Thurston Island Area, Antarctica: Evidence for a Late Paleozoic-Middle Mesozoic Andinotype Continental Margin
Craig M. White and Campbell Craddock
The Journal of Geology
Vol. 95, No. 5 (Sep., 1987), pp. 699-709
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/30065729
Page Count: 11
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Outcrops in the Thurston Island area of West Antarctica consist primarily of plutonic rocks that range in composition from gabbro to granite and yield isotopic dates from 347 to 97 Ma. They intrude amphibolite-grade gneisses of probable early Paleozoic or late Precambrian age and are associated with a suite of basaltic to rhyolitic volcanic rocks of unknown, but probably pre-Tertiary, age. The plutonic rocks have mineralogical and chemical compositions typical of I-type batholiths, and most have calc-alkaline geochem-ical affinities. The assemblage of igneous rocks in the Thurston Island area resembles the igneous suites at active (Andinotype) continental margins; its existence is evidence for a long period of subduction in this part of West Antarctica.
The Journal of Geology © 1987 The University of Chicago Press