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Quaternary fault reactivation in Antarctica associated with Glacial Isostatic Adjustment

Available research on glacial isostatic adjustment (GIA) in Antarctica is sparse, and there are few records of how the stress field is affected by it compared to Arctic and northern regions. Circum-Antarctic coastal and offshore tectonics reveal the presence of faults and rift systems, particularly in West Antarctica, the Weddell Sea, and Prydz Bay. These areas are characterized by a series of complex faults that displace upper sedimentary sequences to depths of 2.5 km. In this study, we investigate the potential for reactivation of glacially induced faults (GIFs) by altered lithospheric stress conditions during ice advances and retreats in past glacial periods. We compiled available information on the dip and strike directions of Antarctic rift systems from the literature and databases. Using finite element simulations that incorporate fault geometries, various rheological and current stress parameters in solid and ice sheet models, it is possible to analyse the probability of fault reactivation due to GIA for the last 200 ka. Because West Antarctica has been subject to greater changes in its ice sheet in recent recorded years compared to East Antarctica, identifying potential sources of GIFs could help us better understand how seismotectonics in Antarctica have been affected by past glacial phases and what the implications of current global climate trends might be.


Ingra Malucelli Barbosa1, Holger Steffen2, Rebekka Steffen2, Elisabeth Seidel1, Karsten Gohl3, Christian Hübscher1
1Institute of Geophysics, University of Hamburg, Hamburg, Germany; 2Geodetic Infrastructure, Lantmäteriet, Gälve, Sweden; 3Alfred Wegener Institute Helmholtz-Centre for Polar and Marine Research, Bremerhaven, Germany
GeoBerlin 2023