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Tony Doré
March 30, 2023 @ 12:15 pm - 1:00 pm
Continental-scale strike-slip faults and their influence on Atlantic and Arctic break-up
Abstract:
An idea that has wide currency in plate tectonics is that extending continental margins will undergo gradual stretching, including the exhumation of continental mantle, unless affected by an extraneous heat source, for example a mantle plume, forming a magma-rich margin. Such margins are typically more abrupt and characterized by seaward-dipping reflectors and underlying high-velocity intrusions. We propose an alternative, or additional mechanism for such margins involving the reactivation of continental transform or transcurrent faults, structures of lithospheric scale originally formed during continental assembly. In this concept. rapid development of abrupt margins results in significant lateral thermal gradients, triggering melt formation. The mechanism also explains the curious near-absence of pre-breakup extension at many such margins, and the frequently short-lived nature of the subaerial magmatic episode prior to the formation of normal oceanic crust – even at margins proposed to be under plume influence. These ideas are supported by lithospheric modelling, by examination of “leaky” transforms in the oceanic and continental domains, and by case-studies from the Arctic and North-Central Atlantic.
Bio:
Tony Doré held senior geoscience and leadership positions with ConocoPhillips and Equinor, and on retirement from Equinor joined the Energy and Geoscience Institute as Global Chief Scientist, based in London. His career involved a long period in Norway, where he formed strong links with universities such as Bergen, Oslo and Tromsø. This association continues with his current role as advisor to postdoctoral work in Bergen. He has worked, and published on, basins all over the world, with emphasis on NW Europe, Arctic and the Americas. Present interests include tectonic evolution of the Arctic, Gulf of Mexico, transform margins, cratonic basins and exploration risk analysis. Tony was recently appointed as Executive Editor of the diamond open access structural geology journal, Tektonika.