The classification and correlation of Sinian sequence stratigraphy on the slope zone in northwestern Hunan Province

Based on a study of the Tianping and Daping sections in Zhangjiajie City, Hunan Province, the authors carried out the classification and correlation of Sinian sequence stratigraphy on the slope facies in the western Hunan Province. Doushantuo Formation is divided into five 3rd grade sequences (ZSQ1-5), and Dengying Formation is divided into four 3rd grade sequences (ZSQ6-9). The lower four 3rd grade sequences (ZSQ1-4) constitute the lower 2nd grade sequence of Sinian, whereas the top 3rd grade sequence ZSQ5 and the four 3rd grade sequences of Dengying Formation(ZSQ6-9)constitute the upper 2nd grade sequence of Sinian. The Sinian sequence stratigraphic classification frameworks between the platform and the slope facies are consistent approximately, hence the correlation could be carried out directly. However, the sequence stratigraphic correlation between the basin and the slope facies can only be carried out in the 2nd grade sequence.