Author:
Jennings S.,Heinson G.,Hasterok D.,Kay B.
Abstract
AbstractIntraplate volcanic provinces present significant natural hazards to many populated regions globally but their origins are poorly understood. Though hypotheses involving mantle plumes are predominant, the Newer Volcanics Province of southeast Australia—a relatively young (< 4.5 Ma), EW trending collection of over 400 volcanic centres—is increasingly attributed to some combination of edge-driven convection (EDC) and shear-driven upwelling (SDU). In this paper, we provide magnetotelluric (MT) data in support of these geodynamic processes. Three-dimensional inversion of 49 new broadband MT sites, in combination with 143 previously collected broadband, long-period, and geomagnetic depth soundings, reveals an elongate zone of moderately low resistivity (∼ 10–300 Ω m) spanning the Mt Gambier subprovince at a depth of between 20 and 40 km. The newly defined Gambier Conductor is contiguous to, and orientationally aligned with, significant step in the seismically-defined lithosphere-asthenosphere boundary (LAB) presented by earlier studies. Moderately low resistivity is interpreted as fluid-catalysed alteration of iron-bearing crust resulting from percolating magmatic volatiles. We argue that localised low resistivity (< 10 Ω m) at ~ 25 km depth in the mid-lower crust is associated with 1.2–3.6% partial melt. Supporting evidence indicates possible crustal thickening from 5.8 Ma at a rate comparable to estimates of SDU-induced surface eruptions and previous NVP production rate estimates.
Publisher
Springer Science and Business Media LLC
Reference51 articles.
1. Blackburn, G. Radiocarbon dates relating to soil development and volcanic ash deposition in South-East South Australia. Aust. J. Earth Sci. 29, 50–52 (1966).
2. McDougall, I., Allsopp, H. L. & Chamalaun, F. H. Isotopic dating of the Newer Volcanics of Victoria, Australia, and geomagnetic polarity epochs. J. Geophys. Res. 71, 6107–6118 (1966).
3. Boyce, J. The Newer Volcanics Province of southeastern Australia: A new classification scheme and distribution map for eruption centres, newer volcanic province. Aust. J. Earth Sci. 60, 449–462 (2013).
4. Boyce, J., Nicholls, I., Keays, R. & Hayman, P. Victoria erupts: The Newer Volcanics Province of south-eastern Australia. Geol. Today 30, 105–109 (2014).
5. Smith, B. W. & Prescott, J. R. Thermoluminescence dating of the eruption at Mt Schank, South Australia. Aust. J. Earth Sci. 34, 335–342 (1987).
Cited by
3 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献