The School of Geography, Earth and Environmental Sciences organises a regular series of research seminars throughout the academic year to which everyone is welcome to attend. Speakers - both external and internal to the University - will talk on topics related to all aspects of Earth Sciences.
Today's speaker is Dr Andrew McCaig from the University of Leeds.The Atlantis Massif is an oceanic core complex where gabbro and ultramafic rocks have been exhumed onto the seafloor by movement of a convex-up detachment fault. This talk will focus on the exhumation history of the Massif, contrasting the deformation history of the detachment fault zone seen in IODP Hole 1309D, and in shallow sea-bed coring on Expedition 357. Numerical modelling results of exhumation, heat flow and hydrothermal circulation show that the main gabbro sampled in Hole 1309D has to have cooled rapidly from above, consistent with palaeomagnetic and geochronological data. In contrast, the extensive high temperature mylonites seen in ODP Hole 735b, in a similar setting on the Southwest Indian Ridge, show that this detachment must have been isolated from any hydrothermal activity.