New Advances in the Study of Cretaceous and Paleogene Boundary on the Wutaigang Section of the Nanxiong Basin, Guangdong Province

Shanghudong and Wutaigang are typical areas responsible for the name Shanghu Formation, where abundant mammal fossils occur. Although the Early and Middle Paleocene mammal fauna was studied in detail long ago, the microfossils in this area have not been reported till now. In recent years, a lot of ostracods, gastropodas and charophytes were found from the Upper Member of Zhenshui Formation to the Lower Member of Shanghu Formation within the Wutaigang section. These ostracods belong to the Porpocypris assemblage and can be subdivided into the Porpocypris orbiculata zone and the P. sphaeroidalis zone. The first occurrence of the P. sphaeroidalis zone almost coincides with that of the Bemalambda zone. The authors suggest that the first occurrence of P. sphaeroidalis limits the bottom boundary of Paleocene, and hence the E/K boundary should lie between the P. sphaeroidalis zone and the P. orbiculata zone.