Palaeozoic Victoria,Australia: Igneous rocks,ages and their interpretation |
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| Authors: | J R Richards O P Singleton |
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| Institution: | 1. Research School of Earth Sciences , Australian National University , P.O. Box 4, Canberra, A.C.T., 2600;2. Department of Geology , University of Melbourne , Parkville, Vic., 3052 |
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| Abstract: | A reconnaissance traverse across Victoria yields 160 K‐Ar dates on igneous rocks from 94 localities. These are supplemented by Rb‐Sr dating in critical cases, and major‐element analyses (some new) on a proportion of the samples. All dates quoted in text and tables, new and previously‐published, have been revised in terms of the latest decay‐constant conventions. The dates range from Early Ordovician (480 Ma) in the west to Late Devonian (360 Ma) among the high‐level intrusives of Central Victoria. The relatively complex age pattern, and the petrochemical character of the rocks, are compared with the published chronology of neighbouring States, and are interpreted in terms of a long‐duration regime of westwards compression, which began in the deformations of the Adelaide System of South Australia, and continued until the Mid‐Devonian Tabberabberan Movement. |
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| Keywords: | Fossils Precambrian Cambrian explosion atmosphere atmospheric oxygen |
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