Impact crater morphology: The origin of the Mertz and Ninnis Glaciers, Antarctica

Abstract

East Antarctica, like West Antarctica, poses several questions about its geologic, geomorphic, and glaciologic history. Among these are questions regarding the origins of the Wilkes Subglacial Basin, the Gamburtsev Mountains, the Wilkes Land Anomaly, subglacial lakes, subglacial topography, and the enigmatic Mertz and Ninnis Glaciers. Located immediately inland of George V Coast at the northern extremity of the Wilkes Subglacial Basin, the Mertz and Ninnis Glaciers display characteristics that have posed questions of their sizes, their accompanying subglacial topography, their existence in tandem within the continental ice sheet and their extensions as glacier tongues offshore in the Southern Ocean. The present study examines in particular the underlying craterform morphology as the potential explanation for these several features based upon surveys of the subglacial topography, which include ground-based geophysical survey, airborne radiosound survey, airborne geophysical survey, and satellite remote sensing of the geomorphology beneath the continental ice sheet. On the basis of these investigations, we propose that the Mertz and Ninnis Glaciers are the result of parallel channelizing subglacial valleys and that the entire Mertz and Ninnis Glacier complex is a function of meteorite crater morphology beneath the East Antarctic continental ice sheet.