On the origin of recent intraplate volcanism in Australia

Davies, D.R. and Rawlinson, N. (2014) On the origin of recent intraplate volcanism in Australia. Geology, 42 (12). pp. 1031-1034. ISSN 0091-7613, 1943-2682 DOI https://doi.org/10.1130/G36093.1

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Many intraplate volcanic provinces do not appear to originate from plate-boundary processes or upwelling mantle plumes. Edge-driven convection (EDC), where a small-scale convective instability (induced by local variations in lithospheric thickness) displaces hot mantle material upward, provides an alternative hypothesis for such volcanism. Recently, EDC has been postulated as the trigger for Quaternary intraplate volcanism in Australia, due to the proximity of a craton edge. However, the Precambrian shield region of the Australian continent has a boundary that is at least 10,000 km long, yet the Newer Volcanics Province (NVP) is contained within a 400 � 100 km region. This brings into question EDC as a causal mechanism, unless nucleation at a single location can be explained. Here, we use a combination of seismic tomography and geodynamic modeling to show, for the first time, that (1) the source of the NVP is restricted to the upper mantle, and (2) mantle upwelling triggered by EDC is localized and intensified beneath the NVP as a result of three-dimensional variations in lithospheric thickness and plate motion-induced shear flow. This study helps to solve the global puzzle of why step changes in lithospheric thickness, which occur along craton edges and at passive margins, produce volcanism only at isolated locations. © 2014 Geological Society of America.

Item Type: Article
Uncontrolled Keywords: NILAREP
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Geology
Volume: 42
Page Range: pp. 1031-1034
Identification Number: https://doi.org/10.1130/G36093.1
Depositing User: Sarah Humbert
Date Deposited: 04 Apr 2017 17:28
Last Modified: 04 Apr 2017 17:28
URI: http://eprints.esc.cam.ac.uk/id/eprint/3876

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