Crustal architecture and geodynamics of North Queensland, Australia: insights from deep seismic reflection profiling  

Authors / CoAuthors

Korsch, R.J. | Huston, D.L. | Henderson, R.A. | Blewett, R.S. | Withnall, I.W. | Fergusson, C.L. | Collins, W.J. | Saygin, E. | Kositcin, N. | Meixner, A.J. | Chopping, R. | Henson, P.A. | Champion, D.C. | Hutton, L.J. | Wormald, R. | Holzschuh, J. | Costelloe, R.D.

Abstract

A deep seismic reflection and magnetotelluric survey, conducted in 2007, established the architecture and geodynamic framework of north Queensland, Australia. Results based on the interpretation of the deep seismic data include the discovery of a major, west-dipping, Paleoproterozoic (or older) crustal boundary, interpreted the Gidyea Suture Zone, separating relatively nonreflective, thick crust of the Mount Isa Province from thinner, two layered crust to the east. East of the Mount Isa Province, the lower crust is highly reflective and is subdivided into three mappable seismic provinces (Numil, Abingdon and Agwamin) which are not exposed at the surface. To the west of Croydon, a second major crustal boundary also dips west or southwest, offsetting the Moho and extending below it. It is interpreted as the Rowe Fossil Subduction Zone. This marks the boundary between the Numil and Abingdon seismic provinces, and is overlain by the Etheridge Province. The previously unknown Millungera Basin was imaged below the Eromanga-Carpentaria basin system. In the east, the Greenvale and Charters Towers Provinces, part of the Thomson Orogen, have been mapped on the surface as two discrete provinces, but the seismic interpretation raises the possibility that these two provinces are continuous in the subsurface, and also extend northwards to beneath the Hodgkinson Province, originally forming part of an extensive Neoproterozoic-Cambrian passive margin. Continuation of this passive margin at depth beneath the Hodgkinson and Broken River Provinces suggests that these provinces (which formed in an oceanic environment, possibly as an accretionary wedge at a convergent margin) have been thrust westwards onto the older continental passive margin. The Tasman Line, originally defined to represent the eastern limit of Precambrian rocks in Australia, has a complicated geometry in three dimensions, which is related to regional deformational events during the Paleozoic.

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document

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• External Publication

( Theme )

• geodynamics

( Theme )

• seismic sections

( Theme )

• structural geology

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• tectonic history

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• Earth Sciences

• Published_Internal

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2011-07-25T00:00:00

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