New Rb-Sr data from the Central Zone of the Damara Orogen, Namibia
Pan-African Rb-Sr whole-rock and mineral ages have been determined for three granitoids and three pegmatites in the low-pressure/ high-temperature Central Zone (CZ) of the Damara Orogen. There is a trend towards more evolved granite types and an increase in ( 87Sr/86Sr)I ratios with time. This can probably be ascribed to the partial melting of crustal material at progressively higher structural levels as the orogeny progressed. In common with the granitoid- and alaskite-hosted uraninite deposits, tin (cassiterite), tungsten (scheelite) skarn, and gold skarn or vein-type mineralisation in the CZ is either hosted by or associated with the younger, late-/post-tectonic intrusions. The Rb-Sr whole-rock dates do not support recent suggestions that Damaran stanniferous pegmatites have been modified by Jurassic-Cretaceous or post-Karoo greisenising fluids
Communications of the Geological Survey of Namibia
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New Rb_Sr data from the Central Zone of the Damara Orogen.pdf | 1.08 MB |