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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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posted on 2023-05-16, 19:52 authored by Anya ReadingAnya Reading, Kennett, BLN, Goleby, B
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-fitting 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 significant contrasts between neighboring terranes; thus, major tectonic units have a velocity profile 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. © 2007 The Geological Society of America.

History

Publication title

Geology

Volume

35

Issue

4

Pagination

379-382

ISSN

0091-7613

Department/School

School of Natural Sciences

Publisher

Geological Society of America

Place of publication

USA

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the earth sciences

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