SILURIAN CONODONT SUCCESSION AND CHRONOSTRATIGRAPHY OF THE BAIZITIAN REGION IN YANBIAN, PANZHIHUA, SICHUAN

The actual evidence and primary information are presented for the first time in China for the continuous Silurian strata from the Lower Silurian, through the Middle Silurian and Upper Silurian, to the Top Silurian, and finally to the Lower Devonian. Nine conodont zones, two conodont assemblage zones and one graptolite zone have been distinguished in a descending order, resulting in the establishment of six stages, i.e. the Panzhihuan, Yongxingian, Qinghean, Chahean, Toudihean and Zhiliuan Stages, and four Series, i.e. the Top Silurian, Upper Silurian, Middle Silurian and Lower Silurian. These results of research have provided the basic information for the establishment of the stratigraphic stages above the Silu-rian Ankang Stage in China. Apart from the graptolite facies in the Longmaxi Formation, the Silurian strata are dominated, without exception, by the carbonate rock facies in which the conodonts are well developed. The complete and continuous conodont succession have provided favourable conditions and foundation for establishment of the Silurian chronostratigraphic system of the shelly-facies in China or even within wider region.