Understanding the structure and dynamics of the lithosphere-asthenosphere system

A workshop on the structure and dynamics of the lithosphere-asthenosphere system was organized at the College de France, Paris, from 19-20 November 2013. The primary focus of the workshop was to enhance understanding of the dynamics interaction between the colder, more brittle lithosphere and the warmer, more ductile asthenosphere by combining constraints from observations and modelling. The dynamics nature of the interaction of the lithosphere and asthenosphere can be best understood when we “stop looking at just one single dataset”, as said by Alan Jones from the Institute of Advanced Studies, Dublin. The worjshop kicked off with a session on the lithosphere-asthenosphere boundary (LAB) across many different oceanic settings. The undoubted highlight of this session was a talk given by Dr. Catherine Rychert, Ocean and Earth Science (OES) at the University of Southampton, on the nature of the LAB beneath hotspots including Hawaii, Iceland and Afar. The results presented by Dr. Rychert allowed for a compelling case to be made regarding melt channeling towards axis of volcanism via pre-existing structures. You can see Kate’s talk at:


Dr. Nicholas Harmon (OES) Southampton chaired a session on upper mantle structure in contrasting oceanic and continental settings. The focus of this session was to understand the nature of the LAB in oceanic and continental settings by bringing together seismological, geochemical and geodynamic evidence.

OES PhD students Saikiran Tharimena and Ryan Gallacher presented posters with results from their ongoing doctoral work on imaging the Ontong Java plateau using SS precursors and surface wave tomography of the Afar triple junction respectively. Saikiran’s work provided evidence for a deep, viscous and radially anisotropic mantle root of the Ontong-Java Plateau which will provide insight into the nature and dynamics of the upper mantle beneath Ontong-Java Plateau. Ryan’s work showed focused mantle low velocities beneath Afar and the Main Ethiopian Rift, offset from the surface magmatic segments. This is interpreted as partial melt in the mantle generating active upwelling by melt buoyancy.