Stratigraphic correlation of the Givetian (late Middle Devonian) deposits in Qujing,Yunnan, southwestern China and the paleogeographic implications

Detailed description of spatio-temporal framework fossil-bearing strata is fundamental significance for understanding the evolution organisms and regional tectonics. The Qujing Haikou formations are two lithological units exposed in eastern Yunnan, southwestern China, both bear rich fossils indicative a Middle Devonian age, while their relationship or lateral correlation remains unclear. Based on detailed observations outcrops these Qujing, as well typical rock characteristics fossil contents, we propose that basically contemporaneous heterotopic facies. From north to south area, transition from Formation gradual shows an increase carbonate component (in terms cumulative thickness rocks) offset, decrease siliciclastic component. distribution Haikou/Qujing indicates development marine environment area during Givetian, part South China Sea connected Paleo-Tethys Ocean, supports transgression might have peaked late Devonian. available biostratigraphic evidence favors expansion Ocean prior