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A Proterozoic Wilson cycle identified by Hf isotopes in central Australia; implications for the assembly of Proterozoic Australia and Rodinia

R. G. Smits, W. J. Collins, M. Hand, R. Dutch and J. Payne
A Proterozoic Wilson cycle identified by Hf isotopes in central Australia; implications for the assembly of Proterozoic Australia and Rodinia
Geology (Boulder) (January 2014) 42 (3): 231-234

Abstract

Current models for the assembly of Proterozoic Australia suggest that the North Australian craton (NAC), West Australian craton (WAC), and South Australian craton (SAC) had amalgamated by at least 1.6 Ga, with possible rafting and reattachment of the SAC by ca. 1.3 Ga. In this scenario, the younger (1.2-1.1 Ga) Grenvillian-aged Musgrave Province of central Australia, which separates all three cratons, has been considered postcollisional to intracratonic. However, new and recent U-Pb and Lu-Hf isotopic analyses of zircons from the Musgrave Province indicate continuous active-margin magmatic activity between 1.7 and 1.2 Ga. A distinctive inverted U-shaped pattern of the Hf array for this 500 m.y. period is evidence of part of a Proterozoic Wilson cycle, with subduction initiation at 1.7 Ga and eventual ocean closure by 1.2 Ga. We estimate that the cycle began at 2.2 Ga. Overlap of the Musgrave zircon age spectra and Hf isotopic array with the along-strike Albany-Fraser orogen (AFO) suggests derivation of the Musgrave Province from the WAC, not the NAC or SAC as previously thought. The Musgrave Province link to the WAC confirms that Australia did not assemble until at least early Grenvillian time (ca. 1.2 Ga). Moreover, because the SAC was part of the much larger Mawson continent, the 1.2 Ga collision was of transcontinental magnitude similar to that of the type-Grenville orogen in Laurentia. This favors an Australia-Mexico (AUSMEX) configuration at 1.2 Ga, rather than the southwestern United States and East Antarctica (SWEAT) or Proterozoic Australia-western United States (AUSWUS) models. The Musgrave-AFO marks a major, underestimated phase of Rodinian assembly.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 3
Title: A Proterozoic Wilson cycle identified by Hf isotopes in central Australia; implications for the assembly of Proterozoic Australia and Rodinia
Affiliation: University of Newcastle, New South Wales Institute of Frontiers Geoscience, Newcastle, N.S.W., Australia
Pages: 231-234
Published: 20140110
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 29
Accession Number: 2014-009759
Categories: StratigraphyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014081
Illustration Description: illus. incl. geol. sketch map
S28°00'00" - S24°30'00", E127°00'00" - E134°00'00"
Secondary Affiliation: University of Adelaide, AUS, AustraliaGeological Survey of South Australia, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201407
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