3:30 PM - 4:00 PM
[SRD41-01] The Granitoid Series and Related Mineralization in the Earth History
Keywords:Granitoid series, Sulfide mineralization, Oxide mineralization
Oxidation status of the earth surface has been changed in the earth history. The oldest foliated granitoids in the Greenland showed low Fe2O3/FeO ratios equivalent to the ilmenite series. In the Berberton region of South Africa, the Archean TTG suites appear to belong also to the ilmenite series, but pink granites younger than 3.0 Ga were found to be the first magnetite series.
In the western Australia, aeromagnetic map shows the Archean Pilbara craton of the ilmenite-series granitoids, but Proterozoic Yilgarn craton is composed dominantly of the magnetite-series. Au-mineralized sheared zones are hosted in the green stones, with the Au-mineralizing systems: a broadly uniform, low to moderate salinity, mixed aqueous-carbonic fluid capable of carrying Au, but limited capacity to transport base metals. The oldest Sn deposits are known to occur together with biotite and aplitic granites of 1.8 - 1.6 Ga (Rb-Sr), within the Bushvelt ultramafic to mafic body. These granitic magmas were found partial melting products of the middle crust by heat brought-up by the Bushvelt ultramafic magmas. The oldest Li-mica pegmatite-bearing dikes (age: 2.5 Ga) have been mined in the western Australia.