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 3...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.482.8839 http://pubs.usgs.gov/of/2007/1047/srp/srp046/of2007-1047srp046.pdf |
| Summary: | 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 melt-present 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. |
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