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New constraints on the seismic structure of West Australia: Evidence for terrane stabilization prior to the assembly of an ancient continent?

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Reading, AM and Kennett, BLN and Goleby, B (2007) New constraints on the seismic structure of West Australia: Evidence for terrane stabilization prior to the assembly of an ancient continent? Geology, 35 (4). pp. 379-382. ISSN 0091-7613

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Abstract

We present a new, near-comprehensive survey of the variations in seismic structure across the West Australian craton at the scale of the main terrane groups. Analyzing data from distant earthquakes recorded at temporary and permanent stations located across the region, we
found the best-fi tting structure by modeling the conversions from P- to S-wave motion (the receiver function) that take place as the seismic energy travels upward through the lithosphere.
Such methods can be used to delineate the extent of cratonic and orogenic terranes in regions where geological exposure of the surface is limited, and they provide an effective alternative to active-source seismic techniques for deep crustal targets. The seismic structure is consistent within several of the individual Archean terranes, most notably the Pilbara, Murchison, and
Southern Cross. These terranes are underlain by lower crust of low seismic velocity and show a sharp seismic Moho. The structure shows signifi cant contrasts between neighboring terranes; thus, major tectonic units have a velocity profi le that is a signature of that terrane or terrane group. We infer that the seismic structure of the Archean crust and upper mantle was fixed before craton assembly and preserved through the subsequent collision and accretion of
the tectonic units that formed the West Australian craton.

Item Type: Article
Keywords: Archean, craton, Australia, seismic structure, receiver function, tectonics, lithosphere
Journal or Publication Title: Geology
Page Range: pp. 379-382
ISSN: 0091-7613
Identification Number - DOI: 10.1130/G23341A.1
Date Deposited: 04 Sep 2007
Last Modified: 18 Nov 2014 03:21
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