21/01/2019 Karin Sigloch (University of Oxford)
Quest for a mantle plume under La Réunion, western Indian Ocean: results of the RHUM-RUM experiment.
The RHUM-RUM experiment aims to clarify the presence or absence of a mantle plume under La Réunion, an intra-plate volcanic hotspot that emerged 65 Ma ago with the eruption of the Deccan flood basalts on India, has since burned a 5,500-km long hotspot track into the Indian Ocean seafloor, and remains among the most active volcanoes on earth.
For 13 months in 2012-2013, RHUM-RUM deployed 57 German and French broadband ocean bottom stations at 2500 to 5400 m depth and over an area of 2000 × 2000 km2, centered on La Réunion Island. The network was complemented by 30 RHUM-RUM land stations that operated for 2-3 years on La Réunion, Mauritius, Madagascar, the Seychelles, and the Iles Eparses.
I will discuss findings about mantle structure from surface to core, focusing on seismic tomography results. This includes mantle body-wave tomography, which reveals La Réunion as part of a hemispheric plume cluster rooted in the African superswell. Rayleigh-wave tomography yielded surprising flow patterns of asthenosphere under the Somali plate and beyond.
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