Cretaceous oblique detachment tectonics in the Fosdick Mountains, Marie Byrd Land, Antarctica
Open-File Report
2007-1047-SRP-046
By: R. McFadden, C.S. Siddoway, C. Teyssier, C.M. Fanning, and S.C. Kruckenberg
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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.
Suggested Citation
McFadden, R., Siddoway, C., Teyssier, C., Fanning, C., Kruckenberg, S., 2007, Cretaceous oblique detachment tectonics in the Fosdick Mountains, Marie Byrd Land, Antarctica: U.S. Geological Survey Open-File Report 2007-1047-SRP-046, 6 p., https://doi.org/10.3133/ofr20071047SRP046.
ISSN: 2331-1258 (online)
Study Area
| 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 |
| Larger Work Title | Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007 |
| Other Geospatial | Antarctica |
| Additional Online Files (Y/N) | N |