Includes the following sessions:
GD1.1/GMPV2.10/SM1.13/TS9.6 Global tectonics and links between surface and deep mantle processes: a tribute to Kevin Burke
Convenors: Mat Domeier (mathew.domeier@geo.uio.no), Lewis Ashwal (lewis.ashwal@wits.ac.za), Susan Webb (susan.webb@wits.ac.za)
Kevin Burke (1929-2018) was one of the greatest geologists of our time and his original and thought-provoking contributions were published steadily for six decades. In this session we commemorate the pioneering work of Kevin and contributions are invited from across the diverse fields that interested him, including Plate Tectonics and the Wilson Cycle at large, the origin of Precambrian greenstone belts, the evolution of the Caribbean and the uplift history of Africa. Kevin often asserted that plate tectonics is an incomplete theory without a clear understanding of its interaction with mantle plumes. He therefore set out to explore this issue more than a decade ago, and with collaborators proposed a simple conceptual mode where the link between plate tectonics and the Earth's deep mantle can be viewed as a simple mass-balance: subducted lithospheric slabs restore mass to the mantle and trigger a return flow toward the surface—including mantle plumes—rising from the margins of two stable and antipodal thermochemical piles in the lowermost mantle. The surface manifestations of plumes include large igneous provinces which punctuate the process of plate tectonics via the creation of new plate boundaries. We welcome contributions that examine surface and deep Earth links based on both observations and numerical models (although notably the latter never seduced Kevin).
SM4.7/GD3.5/GMPV7.6/TS9.5 Hotspots, LIPs and LLSVPs: a global investigation with joint constraints from geochemistry, seismology and geodynamics
Convenors: Maria Tsekhmistrenko (maria.tsekhmistrenko@seh.ox.ac.uk), Catherine Chauvel (catherine.chauvel@univ-grenoble-alpes.fr), Cinzia Farnetani (cinzia@ipgp.fr), Alessandro Forte (forte@ufl.edu), Bernhard Steinberger (bernhard.steinberger@geo.uio.no)
Seismic tomography images large low-velocity provinces (LLVPs) at the core-mantle boundary (CMB), deep mantle plumes, and the connection between them. Geochemistry provides constraints on the age and nature of the material sampled by plumes. Geodynamic modelling suggests interaction of subducting slabs with low-velocity piles at the CMB and traces the geographical source of erupted material. What is needed now is to combine approaches and confront observations from the different fields to build a clear picture of the link between deep structures and surface expressions in volcanoes.
This session aims to bring together scientists from these different fields to better constrain the complex processes in the mantle at all depths with a focus on mantle plumes. We invite contributions from (1) seismic observations and seismic tomography models of mantle plumes and LLSVPs. (2) geodynamic modelling on the origin of LLSVPs and their connection to mantle plumes. (3) tectonic studies with new data (or old data with new flavour). (4) geochemical and petrological studies constraining the nature and evolution of thermochemical plumes. (5) all studies that use novel data collection and visualization techniques to further understand deep mantle structures and their connections to the surface observables.
GD2.1/CL1.33/PS1.12/SM4.19/TS9.9 Plume-lithosphere interactions: geodynamic, tectonic, geophysical, geochemical and planetological evidence
Convenors: Alexander Koptev (alexander.koptev@ifg.uni-tuebingen.de), Anouk Beniest (a.beniest@vu.nl), Taras Gerya (taras.gerya@erdw.ethz.ch)
The emplacement of mantle plumes below lithosphere of different origin and structure is one of the key questions for understanding the 4.5 billion years Earth’s and planetary (e.g., Venus, Mars) evolution and tectonic, seismic and magmatic activity. Although it is widely known that focused mantle upwelling can result in thinning of lithosphere and associated voluminous melt generation, the exact consequences of plume-lithosphere interaction on for example surface evolution and intraplate deformation remain in many aspects unclear. This problem becomes even more acute in the light of current debates on the significance of the lithosphere rheology and lithosphere-asthenosphere boundary and the contribution of mantle plumes to long-term terrestrial and planetary climate change through greenhouse gas emissions from intensive volcanic activity. The methods used to discover plumes, visualize them and understand their behavior vary greatly. We aim with this session to bring together scientists from different fields to exchange their methods and results about mantle plume research. We invite abstracts that offer new insights into the interaction between the plume head and the overlying lithosphere from geophysics, geochemistry, geology, geomorphology, geodynamics, planetology and paleoclimatology perspectives.