Continental ice significance for troughs evolution on glaciated shelves of Arctic and Subarctic

Abstract

Submarine troughs are most typical features of topography of Arctic and Subarctic glaciated shelves. Analysis of recent data on relief and Quaternary sediments as well as sea floor seismic profiling enables to distinguish three types of the shelf troughs and a number of their genetic varieties, it indicates also that geomorphic appearance of troughs has been modeled by Pleistocene ice sheets covering sea floor. Ice bed topography had been already formed before the continental glaciation came into being. At that moment Pre-Quaternary river valleys dissected the Cretaceous surface to the depth of 300-500 m. Glaciers and meltwater broadened and deepened the large cuts. A supposed mechanism is described of Pre-Quaternary river valleys transformation into glacial trough valleys.