Granite ages within the Archaean Pilbara Block,Western Australia |
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| Authors: | J R de Laeter J G Blockley |
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| Institution: | 1. Department of Geophysics and Geochemistry , Australian National University , Canberra, A.C.T., 2600;2. Department of Physics , Western Australian Institute of Technology , Bentley, Western Australia, 6102;3. Geological Survey of Western Australia , 66 Adelaide Terrace, Perth, Western Australia, 6000 |
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| Abstract: | Within the Pilbara Block of Western Australia, a complex of migmatite, gneissic and foliated granite near Marble Bar is intruded by a stock of younger massive granite (the Moolyella Granite) with which swarms of tin‐bearing pegmatites are associated. The age of the older granite has been determined by the Rb‐Sr method as 3,125 ± 366 m.y., and that of the Moolyella Granite as 2,670 ± 95 m.y. Initial Sr87/Sr86 ratios suggest that the older granite is close to primary crustal material, but that the Moolyella Granite consists of reworked material. It probably formed by partial remelting of the older granite. |
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| Keywords: | Cooma Granodiorite fluid‐rock interaction major and trace elements O and Sr isotopes partial melting of sedimentary source Rb‐Sr dating |
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