PALEO-TETHYS EVOLUTION RECORDED IN THE CHANGNING-MENGLIAN BELT, WESTERN YUNNAN, CHINA

As a trunk part of the Paleo-Tethyan archipelago ocean, the Changning- Menglian belt of Western Yunnan, China, presents varied volcano-sedime ntary records ranging in time from Early Devonian through Middle-Late Triassic. The typical pelagic sediments represented by radiolarites ca n not only signify a continuously evolved ocean but also constitute a complicated basin comprising different tectono-sedimentary units. It i s likely that oceanic plateaus of diverse origins played a key role in constructing the pattern of eastern Tethys. The opening and closing o f the Yunnan Tethys are discussed in the paper as well. (C) Academie d es sciences/Elsevier, Paris.