Archaean volcanism and sedimentation near Meekatharra,Western Australia |
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| Authors: | JA Hallberg DN Carter KN West |
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| Institution: | 1. Division of Mineralogy, CSIRO, Wembley, W.A. Australia;2. Shell Minerals Exploration (Australia) Pty. Ltd., Melbourne, Vict. Australia |
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| Abstract: | Archaean volcanic rocks and volcanogenic sediments exposed in a regional syncline south of Meekatharra, Western Australia are described. Initial volcanic activity produced a suite of high-Mg basalts containing 10–19% MgO. Pillowed tholeiitic basalts overlie the high-Mg basalts. These lower units are thought to have been derived from a central fracture zone. The uppermost units consist of volcanogenic sediments interlayered with andesite and dacite flows which appear to have been derived from a marginal andesite pile to the east. The Archaean sequence has been tightly folded, cross-faulted and intruded by post-Archaean dykes.The central succession is predominantly submarine, although the marginal andesite pile may be in part subaerial. Whilst there are some similarities with the Marda complex to the southeast (Hallberg et al., 1976), the rocks near Meekatharra are more analogous to those associated with modern island arcs. |
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