Description
Variable composition including granodiorite, tonalite, trondhjemite, and granophyre. Intrusions include: (1) calc alkaline Trendall Crag granodiorite; (2) Cooper Island granophyre, cogenetic with tholeiitic mafic rocks of the Drygalski Fjord Complex; (3) undifferentiated granitoids including mylonitic granodiorite within the Cooper Bay Shear Zone, dated at 162±2 Ma (Curtis et al.,2010)1.
Age
Middle - Late Jurassic
Map Reference
Curtis, M. L. Geological Map of South Georgia (1:250 000 scale). Sheet 4, (British Antarctic Survey, 2011). Available here.
References
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Curtis, M. L., Flowerdew, M. J., Riley, T. R., Whitehouse, M. J. & Daly, J. S. Andean sinistral transpression and kinematic partitioning in South Georgia. J. Struct. Geol. 32, 464–477 (2010). ↩