Wang Guofu, Pan Shigang, Li Jun, Ren Xinxin & You Hailu (2019)
Age determination of dinosaur-containing fossil formations in the Lower Jurassic Anlongbao, southeastern margin of the Chuxiong Basin, Yunnan.
Journal of Stratigraphy 43(4): 432-441 (in Chinese)
http://oversea.cnki.net/kcms/detail/detail.aspx?dbCode=cjfd&QueryID=4&CurRec=10&filename=DCXZ201904010&dbname=CJFDLAST2020Dinosaur fossils represented by basal sauropodomorphs are rich in the southeastern Chuxiong Basin, Yunnan Province, China, and these fossil-bearing horizons were assigned to the Middle Jurassic in the local 1â200000 geological map, contradicting with the fact that basal sauropodomorphs have never been found in the Middle Jurassic strata worldwide. During the investigation into dinosaurs in the Anlongbao area of the southeastern Chuxiong Basin, the authors found that the previous division and assignment of the Lower Jurassic Fengjiahe Formation were incorrect in this area. Here, we redefine the formation and determine the dinosaur-bearing horizons in this area. And subsequently the Fengjiahe Formation is considered herein to consist of cyclothem interbeds of purplish red silty mudstone, mudstone and purplish red, grayish yellow siltstone and muddy siltstone, overlying the Upper Triassic Shezi Formation and underlying the Middle Jurassic Zhanghe Formation. Its middle and upper parts yield rich dinosaur fossils, and its age is considered to be Early Jurassic. Lithostratigraphic and biostratigraphic studies show no obvious sedimentary discontinuity between the Fengjiahe Formation and the overlying strata as well as between this formation and the underlying strata in this area, indicating that the Lower Jurassic was very probably deposited continuously, a rare phenomenon in central Yunnan Province. Moreover, the middle and upper parts of the Lower Jurassic in this region are rich in dinosaur fossils, providing an important chronostratigraphic basis for studying the early evolution of dinosaurs.