Evolution of the Tethys in Yunnan and Tibet

Abstract

Of the five ophiolite belts recognized in Yunnan and Tibet, two represent Palaeotethys and two Mesotethys. The Lancangjiang belt is regarded as the suture between Gondwana and Eurasia because it is the northern limit of Glossopteris flora and cool-water faunas. Palaeobiogeographic data and ophiolite studies suggest that the Palaeotethys closed in the Late Permian resulting in the extention of the western margin of the Yangtze plate, while the Mesotethys which opened after the closure of the Palaeotethys, disappeared at the end of the Mesozoic. These oceans opened where the metamorphic basement is younger and less crystallized.