Palaeoshoreline records of glacial isostatic adjustment in the Dry Valleys region, Antarctica

Abstract

AbstractWe present a new record of crustal deformation for the Dry Valleys and surrounding region of Antarctica. Values of crustal tilt resulting from the differential uplift of lacustrine strandlines are derived and linked with age data to provide a history of solid earth deformation since deglaciation. We present tilt directions and gradients for 13 strandlines formed c. 18 100–2100 cal yr BP. Derived gradient magnitudes increase exponentially with age and indicate an ongoing response to deglaciation since the Last Glacial Maximum. Azimuths of crustal tilting are consistently down to the SE towards West Antarctica. This tilt pattern is opposite to that predicted by models of glacial isostatic adjustment for Antarctica. Tilt magnitudes are significantly larger than tilted strandlines documented elsewhere in the world, suggesting an influence from thin crust and weak mantle underlying the region. This study presents the first use of lacustrine strandline tilts to document crustal deformation due to glacial unloading in Antarctica and provides an important new datum for constraining glacial isostatic adjustment models.