Geoscientific Investigations in the Tethyan Himalayas.

Abstract

The marine sediments of the Tibetan Tethys Himalaya investigated in the area of Gamba (South Tibet) comprise the stratigraphic range from Upper Aptian (partly even Neocomian) to Paleocene (Ilerdian). They represent a complete record of the last stage of the depositional and tectonic evolution along the northern continental margin of the Indian subcontinent, the passive southern margin of the Tethyan Ocean. The investigated sequence is approximately 3500 m thick. It is stratigraphically and lithofacially described and subsequently subdivided into lithostratigraphic units (Groups, Formations, Members). -- There are five units altogether to be distinguished: The Gamba Group (Upper Aptian to Santonian) which in the lower part comprises black shales and siltstones with intercalated sandstone turbidites, and pelagic marls in the upper part (Gambacunkou Formation); the limestones and calcareous marls rich in fossils of the Zongshan Formation (Campanian to Maastrichtian); the sandstones and interbedded black bituminous limestones of the Jidula Formation (Upper Maastrichtian to Lower Paleocene); the partly nodularly textured limestones of the Zongpu Formation (Middle Paleocene to Ilerdian); and finally the greenish-grey marlstones and continental red beds of the newly established Zongpubei Formation (Eocene).