522 / 2024-09-18 10:11:08

Ancient Tunnel Valleys in the George V Basin of Wilkes Land margin: insight for early glaciation of East Antarctica

Tunnel Valleys,Antarctica

George V Basin (GVB) of the East Antarctic sector is glacially carved estuaries that serve as sediment traps, preserving history of glacial sediment supply over at least for 34 million years.  Knowledge of the GVB’s dynamics is thus key to understanding ice sheet variability and its impact on climate. Here we document the first conclusive evidence of spectacular meltwater channels cutting into a sedimentary substrate has observed in the GVB interpreted as tunnel valleys. Detailed seismic stratigraphic and facies analysis reveal that the valleys were formed after Eocene-Oligocene boundary and filled trough the Oligocene based on the examination of multichannel seismic data from the WEGA survey and IODP318 between 140°E and 155°E. We focus on the geomorphology and stratigraphy of the infill of the the tunnel valleys to gain the first reconstruction of the formation mechanism to better understand the linkage between the tunnel valleys and the regional response of the East Antarctic Ice Sheet EAIS.