Main Andean sinistral shear along the Cooper Bay Dislocation Zone, South Georgia?
Open-File Report
2007-1047-SRP-034
By: M.L. Curtis
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Abstract
The Cooper Bay Dislocation Zone (CBDZ) represents a major NW-SE trending tectonic boundary within
the island of South Georgia that juxtaposes components of a Middle Jurassic to mid-Cretaceous island-arc and back-arc-
basin system. New detailed structural data from the southern end of the dislocation zone reveal that earliest
displacement along the boundary appears to have been associated with dip-slip reverse shear, characterised by
widespread proto- to meso-mylonitic granitic rocks within the basement assemblage exposed to the southwest of the
shear zone. Along the northeast margin, highly sheared and mylonitised metasedimentary and metabasic rocks reveal
sinistral strike-slip kinematics and a sub-horizontal mineral lineation. Narrow zones of sinistral shear are locally superimposed within the basement rocks along the SW margin, that together with the presence of brittle sinistral faults
suggest that the strike-slip component of deformation postdates the dip-slip. Comparison with the tectonic history of the
Rocas Verdas Marginal Basin, Fuegian Andes, suggests that the sinistral shear event preserved along the CBDZ maybe
be related to Late Cretaceous, main Andean orogenic transpression, although a Cenozoic event cannot to ruled out.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Main Andean sinistral shear along the Cooper Bay Dislocation Zone, South Georgia? |
| Series title | Open-File Report |
| Series number | 2007-1047-SRP-034 |
| DOI | 10.3133/ofr20071047SRP |
| Year Published | 2007 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Description | 4 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 |
| Google Analytic Metrics | Metrics page |