New Rb-Sr mineral ages temporally link plume events with accretion at the margin of Gondwana
Open-File Report
2007-1047-SRP-012
By: M.J. Flowerdew, J.S. Daly, and T.R. Riley
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Abstract
Five of six Rb-Sr muscovite mineral isochron ages from the Scotia Metamorphic Complex of the South
Orkney Islands, West Antarctica, average 190 ± 4 Ma. The muscovite ages are interpreted to date foliation-formation
and thus also accretion and subduction at the Gondwana margin. Coincident picrite and ferropicrite magmatism,
indicative of melts from deep-seated depleted mantle, permits a causative link between accretion and the arrival of the
Karoo – Ferrar – Chon Aike mantle plume in the Early Jurassic. Three biotite Rb-Sr mineral isochron ages are
consistently younger and average 176 ± 5 Ma. The biotite ages may record post-metamorphic cooling or more likely
retrogressive metamorphic effects during uplift.
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | New Rb-Sr mineral ages temporally link plume events with accretion at the margin of Gondwana |
| Series title | Open-File Report |
| Series number | 2007-1047-SRP-012 |
| DOI | 10.3133/ofr20071047SRP012 |
| 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 |
| Online Only (Y/N) | N |
| Google Analytic Metrics | Metrics page |