Mid-Cretaceous ductile deformation on the Eastern Palmer Land Shear Zone, Antarctica, and implications for timing of Mesozoic terrane collision

Vaughan, Alan P.M.; Kelley, Simon P.; Storey, Bryan C.. 2002 Mid-Cretaceous ductile deformation on the Eastern Palmer Land Shear Zone, Antarctica, and implications for timing of Mesozoic terrane collision. Geological Magazine, 139 (4). 465-471. https://doi.org/10.1017/S0016756802006672

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Abstract/Summary

Ar–Ar dating of high-strain ductile mylonites of the Eastern Palmer Land Shear Zone in the southern Antarctic Peninsula indicates that reverse movement on the shear zone occurred in late Early Cretaceous times (Albian), and not latest Jurassic times as previously supposed. The Eastern Palmer Land Shear Zone forms a major tectonic boundary, separating suspect arc terranes from rocks of Gondwana continental affinity. The dated mylonites are developed in Lower Jurassic plutonic rocks at Mount Sullivan, eastern Palmer Land, and form part of a zone of ductile reverse deformation up to 25 km wide. Biotite from a fine-grained mafic mylonite yields an Ar–Ar cooling age of 102.8±3.3 Ma. Movement of this age on the Eastern Palmer Land Shear Zone is coeval with circum-Pacific deformation, possibly related to a mantle superplume event, and provides support for allochthonousterrane models for the Antarctic Peninsula with accretion in post-Early Cretaceous times.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1017/S0016756802006672
Programmes:	BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Antarctica in the Dynamic Global Plate System
ISSN:	0016-7568
Additional Keywords:	Antarctic Peninsula, Gondwana, superplumes, orogeny, structural geology
Date made live:	27 Mar 2012 08:36 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/17477

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