[N] 2012 Shaximiao Formation is of Bajocian-Callovian in age
Li, K., Liu, J., Yang, C. & Hu, F. (2011) Dinosaur essamblages from the Middle Jurassic Shaximiao Formation and Chuanjie Formation in the Sichuan-Yunnan Basin, China. Volumina Jurassica, 2011 IX: 21-42
The Shaximiao Formation (Sichuan Basin, China), and the coresponding Chuanjie Formation of the neighboring Yunnan Basin (Sichuan-Yunnan Basin), representing continental Mesozoic strata, are distinguished from the other Chinese Mesozoic units because of the large area over which they are distributed, their lithological charateristics and their abundant vertebrate fossils.
This paper analyses and summarizes the dinosaur fossils from the Shaximiao Formation and compares them to other vertebrate groups of the same or simular ages, both in China and abroad. For the first time, this paper presents the viewpoint that the upper member of the Shaximiao Formation is of Middle Jurassic age (Bathonian-Callovian).
Furthermore, we claim that the entire Shaximiao Formation is of Bajocian-Callovian age (middle-late part of Middle Jurassic). This conclusion is supported by the age inferred from invertebrate fossils and radiometric dating (165-178 Ma).
The composition, evolution and geological age of the vertebrate fauna (particularly dinosaur fossils), as well as their comparison to the dinosaur fauna from the other parts of the Sichuan-Yunnan Basin (Chuanjie Fm.) is discussed.
Middle Jurassic dinosaur assemblages from China show marked differences compared with other dinosaur assemblages in the world, and this is explained by geographical isolation.