Decompression melting driving intraplate volcanism in Australia: Evidence from magnetotelluric sounding

Aivazpourporgou, Sahereh, Thiel, Stephan, Hayman, Patrick C., Moresi, Louis N., & Heinson, Graham (2015) Decompression melting driving intraplate volcanism in Australia: Evidence from magnetotelluric sounding. Geophysical Research Letters, 42(2), pp. 346-354.

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A long-period magnetotelluric (MT) survey, with 39 sites covering an area of 270 by 150 km, has identified melt within the thinned lithosphere of Pleistocene-Holocene Newer Volcanics Province (NVP) in southeast Australia, which has been variously attributed to mantle plume activity or edge-driven mantle convection. Two-dimensional inversions from the MT array imaged a low-resistivity anomaly (10-30Ωm) beneath the NVP at ∼40-80 km depth, which is consistent with the presence of ∼1.5-4% partial melt in the lithosphere, but inconsistent with elevated iron content, metasomatism products or a hot spot. The conductive zone is located within thin juvenile oceanic mantle lithosphere, which was accreted onto thicker Proterozoic continental mantle lithosphere. We propose that the NVP owes its origin to decompression melting within the asthenosphere, promoted by lithospheric thickness variations in conjunction with rapid shear, where asthenospheric material is drawn by shear flow at a "step" at the base of the lithosphere.

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7 citations in Scopus
7 citations in Web of Science®
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ID Code: 84949
Item Type: Journal Article
Refereed: Yes
Keywords: Australia, decompression, magnetotelluric, melt, shear, volcanoes, Magnetotellurics, Melting, Shear flow, Shearing, Decompression melting, Lithospheric thickness, Magnetotelluric soundings, Mantle lithosphere, Southeast australia, Structural geology, accretion, lithosphere, magnetotelluric method, mantle convection, plate tectonics, volcanism
DOI: 10.1002/2014GL060088
ISSN: 0094-8276
Divisions: Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2015 American Geophysical Union
Deposited On: 23 Jun 2015 06:22
Last Modified: 25 Jun 2017 00:01

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