3430 to 3417Ma calc-alkaline volcanism in the McPhee Dome and Kelly Belt, and growth of the eastern Pilbara Craton

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doi: 10.1016/S0301-9268(97)00061-2
Authors:Barley, M. E.; Loader, S. E.; McNaughton, N. J.
Author Affiliations:Primary:
CRA Exploration Pty., Box Hill, Victoria, Australia
Other:
University of Western Australia, Nedlands, West. Aust., Australia
Volume Title:tectonics and metallogenic evolution of the Pilbara Craton
Volume Authors:Barley, M. E., editor
Source:The tectonics and metallogenic evolution of the Pilbara Craton, edited by M. E. Barley and S. E. Loader. Precambrian Research, 88(1-4), p.3-23. Publisher: Elsevier, Amsterdam, International. ISSN: 0301-9268
Publication Date:1998
Note:In English. 61 refs.Special issue; illus., incl. 3 tables, geol. sketch maps
Summary:The McPhee Dome and Kelly Belt in the eastern Pilbara Craton contain well-preserved, proximal, shallow-marine, dominantly-intermediate, volcanic successions. These have SHRIMP U-Pb zircon ages of 3430±3 and 3417±9Ma respectively, which are younger than geochemically similar ∼3.52 and ∼3.47 to 3.45Ga suites in other eastern Pilbara greenstone belts. Basalts, andesites and dacites from the McPhee Dome are similar in composition to modern arc rocks, whereas dacites and rhyodacites from the Kelly Belt have geochemical characteristics of Archaean tonalite-trondhjemite-granodiorite (TTG) magmas. The geochemistry of the McPhee Dome basalts, basaltic andesites and dacites most likely reflects infracrustal fractional crystallization of a mantle derived magma combined with assimilation of older crust, or a silicic melt. In contrast the Kelly Belt dacites and rhyodacites were most likely derived by melting of subducted mafic crust. The extensional submarine environment of pre-3.4 Ga, dominantly mafic and intermediate volcanism in the eastern Pilbara differs from that of approximately coeval granitoid magmatism. The pre-3.4 Ga granitoids have the major and trace element features of TTG suites and appear to have been emplaced into already thick crust culminating in core complex formation. Available data are most consistent with growth of the eastern Pilbara Craton in convergent tectonic settings, involving pulses of extensional shallow-marine, arc-like volcanism between 3.52 and 3.42 Ga, overlapping with, and/or punctuated by, periods of crustal thickening and the intrusion of complex TTG granitoid batholiths. Abstract Copyright (1998) Elsevier, B.V.
Sections:Petrology
Subsections:General
Subjects:Absolute age; Archean; Assimilation; Batholiths; Calc-alkalic composition; Crustal thickening; Dates; Extension tectonics; Fractional crystallization; Geochemistry; Intrusions; Ion probe data; Magmas; Magmatism; Major elements; Marine environment; Mass spectra; Melts; Metals; Nesosilicates; Orthosilicates; Precambrian; Rare earths; Sampling; Shallow-water environment; SHRIMP data; Silicates; Spectra; Tectonics; Trace elements; U/Pb; Volcanism; Whole rock; Zircon; Zircon group; Australasia; Australia; Pilbara Craton; Western Australia; Copper Gorge; Duffer Formation; Kelly Belt; McPhee Dome; North Pole Dome
Abstract Numbers:98M/4236
Record ID:1998034863
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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