Geomorphology and structural position of the Ob'trench (Indian Ocean)

Abstract

Morphology of depressions which the Ob'trench consists of is discussed using data of recent geological and geophysical studies. Some regularity in the trench topography indicates that it becomes younger eastward. The eastern part of the trench is proved to be formed simultaneously with the Naturalist basin. Seismic data compared with deep sea drilling results and the bottom sediments composition analysis suggest the Ob'trench came into being on a carbonate platform in Eocene-Oligocene time and at first stages developed as subcontinental rift.