STRATIGRAPHY,SEDIMENTOLOGY AND TECTONIC PALAEOGEOGRAPHY OF THE NANPIHE GROUP IN THE CHANGNING-MENGLIAN ZONE,SOUTHWESTERN YUNNAN

The Nanpihe Group is located in the western part of the Changning-Menglian zone in southwestern Yunnan.Although its stratigraphic successions have been reworked chaoti-cally by tectonism,there exist a lot of stratal slices with relatively continuous sequences. The sedimentary characteristics and tectonic settings enable the distinction of three mem-bers:upper,middle and lower members.The lower member of the Nanpihe Group is made up of a series of turbidites,fluxoturbidites,debris flow deposits and contourites.The middle and upper members of the group consist of the deposits on the margins of the deep-water oceanic basin.The tectonic settings of the group represent the deep-water exten-sional continental slope to oceanic basin margin environments on the passive continental margin.The principal source of detritus lay to the western Baoshan-Gengma block.