Orals

Subduction drives plate tectonics, generates the major proportion of subaerial volcanism, forms continents, and entrains surface material back to the deep Earth. Therefore, it is arguably the most important geodynamical phenomenon on Earth and the major driver of global geochemical cycles. Seismological data show a fascinating range in shapes of subducting slabs. Arc volcanism illustrates the complexity of geochemical and petrological phenomena associated with subduction. Surface topography provides insight in the orogenic processes related to subduction and continental collision.

Numerical and laboratory modelling studies have successfully built our understanding of many aspects of the geodynamics of subduction zones. Detailed geochemical studies, investigating compositional variation within and between volcanic arcs, provide further insights into systematic chemical processes at the slab surface and within the mantle wedge, providing constraints on thermal structures and material transport within subduction zones. However, with different technical and methodological approaches, model set-ups, inputs and material properties, and in some cases conflicting conclusions between chemical and physical models, a consistent picture of the controlling parameters of subduction-zone processes has so far not emerged.

This session aims to follow subducting lithosphere on its journey from the surface down into the Earth's mantle, and to understand the driving processes for deformation and magmatism in the over-riding plate. We aim to address topics such as: subduction initiation and dynamics; changes in mineral breakdown processes at the slab surface; the formation and migration of fluids and melts at the slab surface; primary melt generation in the wedge; subduction-related magmatism; controls on the position and width of the volcanic arc; subduction-induced seismicity; mantle wedge processes; the fate of subducted crust, sediments and volatiles; the importance of subducting seamounts, LIPs, and ridges; links between near-surface processes and slab dynamics and with regional tectonic evolution; slab delamination and break-off; the effect of subduction on mantle flow; and imaging subduction zone processes.

With this session, we aim to form an integrated picture of the subduction process, and invite contributions from a wide range of disciplines, such as geodynamics, modelling, geochemistry, petrology, volcanology and seismology, to discuss subduction zone dynamics at all scales from the surface to the lower mantle, or in applications to natural laboratories.