Stagnant slabs at the transition zone linked to widespread volcanism in Eastern Australia and Zealandia

Nov 19, 2019·
Dr. Ben Mather
Dr. Ben Mather
· 0 min read
Abstract
The eastern margin of Australia and Zealandia has experienced extensive mafic volcanism since Australia broke away from Antarctica approximately 80 million years ago. A plume origin has been proposed for age-progressive volcanism observed in leucitite suites on the continent and the Lord Howe rise offshore. Aside from these exceptions, the majority of eruptions in the region exhibit no clear age progression. From our plate reconstruction of the Australia-Zealandia region over the last 80 million years that has most likely accumulated at the transition zone. Compilations of P and S-wave tomography add support for an anomalous transition zone in the region. The relationship between 143Nd/144Nd and 206Pb/204Pb isotopic ratios in volcanic samples suggest a high degree of lithospheric interaction that is increasingly more pronounced at high latitudes. We propose that widespread, non-age progressive volcanism results from sporadic upwellings triggered by changes in plate kinematics which entrains stagnant subducted material at the transition zone. The most pronounced pulse of volcanism occurs at 23 Ma and coincides with an abrupt increase in plate velocity and subduction flux. This provides a framework through which to explain non-age progressive volcanism in a region of anomalous mantle composition.
Date
Nov 19, 2019 2:30 PM — 2:45 PM
Location

Port Lincoln, South Australia

events
PyGPlates Intraplate Volcanism
Dr. Ben Mather
Authors
Dr. Ben Mather
ARC Industry Research Fellow

I am an ARC Industry Research Fellow in the School of Geography, Earth and Atmospheric Sciences at The University of Melbourne. I am an expert in fusing Earth evolution models with data to understand how groundwater moves critical minerals through the landscape. Related research interests include the cycling of volatiles within the Earth, probabilistic thermal models of the lithosphere to unravel past tectonic and climatic events, and understanding the how enigmatic volcanoes form.

I am a vocal advocate for the integral role of geoscience in responding to challenges we face in transitioning to the carbon-neutral economy. As an expert in my field, I have been interviewed in national and international print media, TV, and radio on a wide variety of subjects including earthquakes, volcanoes, groundwater, and critical minerals.