Tectonic models for Proterozoic Australia: implications from the magmatic record  

Authors / CoAuthors

Champion, D.C.

Abstract

The evolution of the Paleo- and Mesoproterozoic of Australia is controversial. Early tectonic models were largely autochthonous, in part driven by the chemical characteristics of Proterozoic felsic magmatism: overwhelmingly potassic, often with elevated Th and U contents, and with evolved isotopic signatures, consistent with crustal sources and the implication they were not generated within continental arcs. This model has been increasingly challenged over the last 30 years, driven by the recognition of the diversity of Proterozoic magmatism, of linear magmatic belts often with subduction-compatible geochemistry and juvenile isotopic signatures, and of across-strike trends in isotope signatures, all consistent with continental margin processes. These, and other geological evidence for crustal terranes, suggest subduction-related tectonic regimes and collisional orogenesis. Current tectonic models for the Australia Proterozoic invoke such processes with varying number of continental fragments and arcs, related to assembly/break-up of the Nuna Supercontinent. Problems still exist however as the observations of early workers still largely hold-much Proterozoic magmatism was intracratonic, and interpreted backarc magmatism largely lacks obvious related arcs. This has led to more recent hybrid arc-plume models. No one model is completely satisfactory, however, reflecting ambiguity of geochemical data and secular arguments (when did modern-style tectonics actually begin).

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nonGeographicDataset

eCat Id

73415

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Keywords

• External Publication

( Theme )

• geochemistry

( Theme )

• tectonic history

( Theme )

• geology

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2012-01-01T00:00:00

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Australian Government Security ClassificationSystem    

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Creative Commons Attribution 4.0 International Licence    

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geoscientificInformation

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Abstract for the IGC, Brisbane, 2012

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[-44.0, -10.0, 112.0, 156.0]

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