The Mushandike Granite; further evidence for 3.4 Ga magmatism in the Zimbabwe Craton

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doi: 10.1017/S0016756801004939
Authors:Dodson, M. H.; Williams, I. S.; Kramers, J. D.
Author Affiliations:Primary:
Australian National University, Research School of Earth Sciences, Canberra, Australia
University of Zimbabwe, Zimbabwe
Volume Title:Geological Magazine
Source:Geological Magazine, 138(1), p.31-38. Publisher: Cambridge University Press, London, United Kingdom. ISSN: 0016-7568
Publication Date:2001
Note:In English. 24 refs.; illus., incl. 1 table, geol. sketch map
Summary:SHRIMP U-Pb zircon analyses on zircon have resolved the previously discrepant published ages for the Mushandike granite (2920 ± 170 m.y., 3450 ± 130 m.y.) in favour of the older; indistinguishable values of 3374 ± 7 and 3368 ± 11 m.y. being determined for the magma crystallization age. With other published data from elsewhere in southern Zimbabwe, these results imply a widespread magmatic event at ∼ 3350 m.y. A single zircon core giving an age of 3460 m.y., and the granite's previously measured Nd model age suggest the Mushandike magma possibly incorporated remobilized basement similar to the ∼ 3500 m.y. Tokwe gneisses 30 km to the W. Published Rb-Sr and Pb-Pb datasets show evidence of late Archaean disturbance of Sr and Pb isotope systematics. In the absence of exposed contacts of the Mushandike granite and neighbouring Mushandike stromatolitic limestone, the new U-Pb emplacement age suggests the limestone is unconformable on the granite. [J.F.]
Sections:Age determination
Subjects:Absolute age; Archean; Cratons; Crystal zoning; Dates; Granites; Igneous rocks; Magmatism; Neoarchean; Nesosilicates; Orthosilicates; Plutonic rocks; Precambrian; Silicates; U/Pb; Zircon; Zircon group; Africa; Southern Africa; Zimbabwe; Zimbabwe Craton; Mushandike Granite; Mushandike National Park
Coordinates:S200000 S200000 E0310000 E0300000
Abstract Numbers:01M/2407
Record ID:2002046452
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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