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The geology of Cape Dubouzet, northern Antarctic Peninsula: continental basement to the Trinity Peninsula Group?

Hervé, Francisco; Lobato, Jorge; Ugalde, Ignacio; Pankhurst, Robert J.. 1996 The geology of Cape Dubouzet, northern Antarctic Peninsula: continental basement to the Trinity Peninsula Group? Antarctic Science, 8 (4). 407-414. 10.1017/S0954102096000582

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Abstract/Summary

Cape Dubouzet is mainly composed of a volcanic-subvolcanic complex of extrusive rhyolitic breccias, a banded rhyolite and a semi-annular body of dacite porphyry rich in xenoliths of metamorphic rocks. Major and REE geochemistry indicate that the volcanic rocks are calc-alkaline and that they are genetically related by fractional crystallization of a plagioclase-bearing assemblage from a common magma. Rb-Sr data suggest that the rhyolitic complex is of Middle-to-Late Jurassic age, and that it is intruded by Late Cretaceous stocks of banded diorite and gabbro. All these rocks are partially covered by moraines whose clasts are of local provenance. Xenoliths in the dacite porphyry suggest that the northern tip of the Antarctic Peninsula is underlain by a metamorphic complex composed of amphibolites, meta-tonalites and pelitic gneiss containing garnet, sillimanite, cordierite, hercynite, and andalucite. Such rocks are not known in the Scotia metamorphic complex, nor in the Trinity Peninsula Group and its low grade metamorphic derivatives, which also occur as rare xenoliths in the dacite. Previous dating of xenoliths collected from the moraines suggested a late Carboniferous age for this amphibolite-grade metamorphism. Both the Jurassic-Cenozoic magmatic arc of the Antarctic Peninsula and the accretionary complex rocks of the Trinity Peninsula Group were thus developed, at least in part, over pre-existing continental crust.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1017/S0954102096000582
Programmes: BAS Programmes > Pre 2000 programme
ISSN: 0954-1020
Additional Keywords: Antarctic Peninsula, Mesozoic, metamorphic basement, silicic volcanism, xenoliths
Date made live: 15 Nov 2016 10:57 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/515143

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