New progress in the study of the Jurassic of central Yunnan

Based on the Chuanjie section at Lufeng County, the lithological units of the Upper and Lower Lufengian System (group and formation) used for the Kunming stratigraphic area for more than half a century are revised; the Lufeng Formation (including the Shawan Member and Zhangjia'ao Member) is redefined and renamed; the Chuanjie Formation, Laoluocun Formation and Madishan Formation are newly erected besides the Anning Formation that is still used; and the Upper Jurassic is separated in the Lufeng area for the first time. Based on fossil vertebrate faunas occurring in various formations, the Early, Middle and Late Jurassic are erected respectively. By further investigation and study, the authors confirm that the Upper Triassic Shezi Formation and the Jurassic were continuously deposited in the Kunming area. By correlation, the authors determine the base of the Middle Jurassic Chuanjie Formation and the top of the Upper Jurassic Anning Formation in the Kunming area, while the green sandstone member of the Zhanghe Formation and the yellow mudstone member of the Tuodian Formation are lacking in the Chuxiong basin. In addition, fossil insects are first discovered in the Late Jurassic Tuodian Formation. The insects fossils are associated with Estheria. The types of the insects and Estheria are different from those of the boreal faunas. Based on those new research results, the authors propose a scheme of stratigraphic correlation of the Jurassic in the Kangdian (Xikang-Yunnan) stratigraphic subregion.