Upper Devonian conodonot and brachiopod biostratigraphic in Quanzhou area, Guangxi

The Devonian strata are developed in northeastern Guilin area, where there exist large quantities of fossils, which are of great significance for studying the Devonian biostratigraphy in southern China. The authors collected and studied conodonts and brachiopods from Changlongjie Formation, Xikuangshan Formation and Menggongao Formation in the Middle-Upper Devonian strata of the study area and obtained 104 pieces of conodonts and 34 brachiopod fossils. 20 species of 21 genus of conodonts as well as 9 species of 6 genus of conodonts were identified. According to the important conodonts fossils, 8 conodont zones were set up from the bottom to the top in the study area:Icriodus brecis Zone, Schmidtognathus hermanni-Polygnathus cristatus Zone, Schmidtognathus wittekindtii Zone, Palmatolepis linguiformis Zone, Palmatolepis triangularis Zone, Palmatolepis rhomboidea Zone, Icriodus cornutus Zone, Palmatolepis gracilis manca-Rhodalepis polylophodontiformis Zone, which indicates that Changlongjie Formation, Xikuangshan Formation and Menggongao Formation correspond to the upper part of Frasnian stage, the bottom part of Famennian stage and the middle and upper part of Famennian stage, respectively. In addition, the authors indicated Frasnian stageFamennian stage boundary in the study area according to the first appearance of Palmatolepis triangularis, 2 combinations were established in the study area:Cyrtospirifer Zone and the Yunnanella-Tenticosififer Zone, which correspond to Palmatolepis falsiovalis Zone, Palmatolepis linguiformis Zone, Palmatolepis marginifera.