A field guide to basin architecture and crustal evolution in the Paleoproterozoic-earliest Mesoproterozoic sequences of Mount Isa, northern Australia: a record of (Nuna) supercontinent breakup  


Authors / CoAuthors

Gibson, G.M. | Southgate, P.N. | Neumann, N.L. | Henson, P.A. | Young, B.

Abstract

Paleoproterozoic-earliest Mesoproterozoic sequences in the Mount Isa region of northern Australia preserve a 200 Myr record (1800-1600 Ma) of intracontinental rifting, culminating in crustal thinning, elevated heat flow and establishment of a North American Basin and Range-style crustal architecture in which basin evolution was linked at depth to bimodal magmatism, high temperature-low pressure metamorphism and the formation of extensional shear zones. This geological evolution and record is amenable to investigation through a combination of mine visits and outcrop geology, and is the principal purpose of this field guide. Rifting initiated in crystalline basement -1840 Ma old and produced three stacked sedimentary basins (1800-1750 Ma Leichhardt, 1730-1670 Ma Calvert and 1670-1575 Ma Isa superbasins) separated by major unconformities and in which depositional conditions progressively changed from fluviatile-lacustrine to fully marine. By 1685 Ma, a deep marine, turbidite-dominated basin existed in the east and basaltic magmas had evolved in composition from continental to oceanic tholeiites as the crust became increasingly thinned and attenuated. Except for an episode of minor deformation and basin inversion at c. 1640 Ma, sedimentation continued across the region until onset of the Isan Orogeny at 1600 Ma.

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document

eCat Id

74397

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ED  

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Commonwealth of Australia (Geoscience Australia)  

  Custodian

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Keywords

  • GA PublicationRecord
( Theme )
  • crustal structure
( Theme )
  • sedimentary basins
( Theme )
  • geochronology
( Theme )
  • tectonic history
( Theme )
  • sequence stratigraphy
Australian and New Zealand Standard Research Classification (ANZSRC)
  • Earth Sciences
  • Published_External

Publication Date

2012-01-01T00:00:00

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Creative Commons Attribution 4.0 International Licence    

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geoscientificInformation

Series Information

Record 2012/053

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