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GD3.2

Lower mantle heterogeneity – linking slab and LLSVP dynamics
Convener: Abigail Bull  | Co-Conveners: Grace E. Shephard , Dan J. Bower 
Posters
 / Attendance Wed, 15 Apr, 17:30–19:00  / Blue Posters
Tomographic models reveal a lower mantle dominated by broad regional areas of lower-than-average shear-wave speeds beneath Africa and the Central Pacific. The origin and long-term evolution of the anomalous regions, termed LLSVPs (“large low shear velocity provinces”), remains enigmatic and studies to further the community's understanding of the time-dependent dynamics of the LLSVPs have gained increased interest and effort amongst the broad geodynamic community. Of particular debate is the stability, longevity and thermal versus chemical nature of these provinces. Furthermore, the LLSVPs are encircled by regions of higher-than-average shear-wave speeds, commonly associated with Mesozoic and Cenozoic subduction. The structure and evolution of the deepest mantle is therefore intrinsically linked with the history of plate motion at the surface, and resolving both domains is key to generating holistic geodynamic models. Intimately tied to the discussion is constraining the history of subduction in global plate reconstructions. Using palaeomagnetic and paleogeographic constraints, plate reconstructions are being pushed back to the Early Paleozoic with ever-increasing temporal and spatial resolution and can be coupled with 3D whole mantle models. Modelling slab-LLSVP interaction within the lowermost mantle also requires a multi-scale and multi-disciplinary consideration, not limited to, absolute reference frames and net lithospheric rotation, phase transitions as well as the relation to deep-seated plume generation and distribution. We invite abstracts covering the multi-scale and intertwined aspects of lower mantle dynamics, including slab and LLSVP interaction.