The discovery of the Jiannan shelf in the southeastern part of the KaijiangLiangping shelf

On the basis of outcrops, cores and seismic data in this study and the previous data, the author in this study proposes a new shelf, i. e., the Jiannan shelf that represents the southeastward extended part of the Kaijiang-Liangping shelf penetrated from the Xuanhan-Daxian-Liangping-Kaijiang zone southeastwards to the Jiannan area during the Changxingian, and may be connected with West Hubei shelf in the east. Compared with the Kaijiang-Liangping shelf, the Jiannan shelf has the following features. (1) The Jiannan shelf is a shallow-water shelf. (2) The Jiannan shelf was initiated during the early-middle Changxingian and terminated due to the filling up during the late stages of the Changxingian. (3) The Jiannan shelf and its adjacent areas exhibit a carbonate ramp model in which the Changxingian bioherms occur as excellent dolostone reservoirs with good physical properties.