Lithospheric Erosion in the Patagonian Slab Window, and Implications for Glacial Isostasy

The Patagonian slab window has been proposed to enhance the solid Earth response ice mass load changes in overlying Northern and Southern Icefields (NPI SPI, respectively). Here, we present first regional seismic velocity model covering entire north-south extent of window. A slow anomaly uppermost mantle indicates warm temperature, low viscosity, possibly partial melt. Low velocities just below Moho suggest that lithospheric thermally eroded over youngest part slowest is north 49°S, implying NPI northern SPI overlie lower viscosity than southern SPI. This comprehensive mapping provides key evidence supporting previously hypothesized connection between post-Little Ice Age anthropogenic loss rapid geodetically observed glacial isostatic uplift (?4 cm/yr).