Mantle convection and possible mantle plumes beneath Antarctica – insights from geodynamic models and implications for topography

• Published in: Geological Society, London, Memoirs
• Main Authors: Bredow, E., Steinberger, B., Gassmöller, R., Dannberg, J.
• Format: Book Part
• Language: unknown
• Published: 2022
• Subjects: Antarctic; Pacific; Tilting; West Antarctica; Antarc*; Antarctica
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5003341

This chapter describes the large-scale mantle flow structures beneath Antarctica as derived from global seismic tomography models of the present-day state. In combination with plate reconstruc11 tions, the time-dependent pattern of paleosubduction can be simulated and is also shown from the rarely seen Antarctic perspective. Furthermore, a dynamic topography model demonstrates which kind and scales of surface manifestations can be expected as a direct and observable result of mantle convection. The last section of the chapter features an overview of the classical concept of deep-mantle plumes from a geodynamic point of view and how recent insights, mostly from seismic tomography, have changed the understanding of plume structures and dynamics over the past decades. The long-standing and controversial hypothesis of a mantle plume beneath West Antarctica is summarised and addressed with geodynamic models, which estimate the excess heat flow of a potential plume at the bedrock surface. However, the predicted heatflow is small while differences in surface heat flux estimates are large, therefore the results are not conclusive with regard to the existence of a West Antarctic mantle plume. Finally, it is shown that global mantle flow would cause tilting of whole-mantle plume conduits beneath West Antarctica such that their base is predicted to be displaced about 20◦ northward relative to the surface position, closer to the southern margin of the Pacific Large Low Shear Velocity Provinc