Oblique dilation, melt transfer, and gneiss dome emplacement
Date
2010
Authors
McFadden, R.R
Teyssier, C
Siddoway, Christine Smith
Whitney, Donna
Fanning, Christopher
Journal Title
Journal ISSN
Volume Title
Publisher
Geological Society of America Inc
Abstract
The upward transfer of partially molten crust and the formation of gneiss domes and metamorphic core complexes commonly take place by localization of normal or oblique extension in the middle and upper crust. In Marie Byrd Land, Antarctica, a transition from wrench to oblique extension occurred during oblique plate divergence along the East Gondwana margin and intracontinental crustal extension associated with the West Antarctic Rift System in mid-Cretaceous time. Migmatites in the Fosdick dome record steep fabrics formed during wrenching, and associated granite networks display crystallization ages of 117-115 Ma. These steep fabrics are overprinted by subhorizontal foliation and leucogranite sheets with crystallization ages in the 109-102 Ma range. Syntectonic emplacement of granite sheets in the South Fosdick detachment zone indicates that detachment tectonics led to rapid exhumation of the terrain by 100 Ma. This study has implications for understanding melt transport, magma accumulation, and the formation of detachments in an oblique tectonic setting.
Description
Keywords
Keywords: Antarctica; Crustal extension; Crystallization age; Gneiss dome; Leucogranites; Marie Byrd Land; Metamorphic core complex; Mid-Cretaceous; Oblique extension; Rift systems; Tectonic settings; Upper crust; Crystallization; Domes; Fabrics; Granite; Tectonics
Citation
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Source
Geology
Type
Journal article