Geophysical studies in the Ross Sea region

Abstract

Geophysical studies in the Ross Sea and over the Ross Ice Shelf have defined the major structural features of this morphological depressed region (the Ross Embayment) between East and West Antarctica. Deep sedimentary basins or troughs containing over 2500 m of sediments occur either side ofa basement ridge which runs north-south through central Ross Sea and apparently extends under the Ross Ice Shelf This ridge marks the boundary zone between two regions which had a different late Cenozoic tectonic history. Under the Ross Ice Shelfthe structural trends to the east of this boundary zone change to an approximately northwest-southeast direction, parallel to the Transantarctic Mountains. The crust is thinner under this region than in either East Antarctica (40 km) or West Antarctica (30 km), This thinner crust suggests that the Ross Embayment may result froni crustal rifting, and its formation and structural trends may be related to plate motions and changes in motion in the south Pacific Ocean during the late Cretaceous and Cenozoic. The Transantarctic Mountains are one of the major morphological and geological features of Antarctica, coinciding with the large rapid change in crustal thickness from the Ross Embayment to East Antarctica. The history of the formation of this mountain belt remains one of the outstanding problems of the region.