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Cretaceous oblique detachment tectonics in the Fosdick Mountains, Marie Byrd Land, Antarctica

Open-File Report 2007-1047-SRP-046

By:
, , , ,
DOI: 10.3133/ofr20071047SRP046

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Abstract

The Fosdick Mountains form an E-W trending migmatite dome in the northern Ford Ranges of Marie Byrd Land, Antarctica. Pervasively folded migmatites derived from lower Paleozoic greywacke and middle Paleozoic plutonic rocks constitute the dome. New field research documents a transition from melt-present to solid-state deformation across the south flank of the dome, and a mylonitic shear zone mapped for 30 km between Mt. Iphigene and Mt Richardson. Kinematic shear sense is dextral normal oblique, with top-to-the-SW and -WSW transport. A U-Pb age of 107 Ma, from a leucosome-filled extensional shear band, provides a meltpresent deformation age, and a U-Pb age of 96 Ma, from a crosscutting granitic dike, gives a lower age limit for deformation. The shear zone, here named the South Fosdick detachment zone, forms the south flank of the migmatite dome and was in part responsible for the exhumation of mid-crustal rocks.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Cretaceous oblique detachment tectonics in the Fosdick Mountains, Marie Byrd Land, Antarctica
Series title:
Open-File Report
Series number:
2007-1047-SRP-046
DOI:
10.3133/ofr20071047SRP046
Year Published:
2007
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Description:
6 p.
Larger Work Type:
Report
Larger Work Subtype:
USGS Numbered Series
Other Geospatial:
Antarctica
Additional Online Files(Y/N):
N