Shixi Fm

The Shixi Formation was named by the Beijing College of Geology in 1961. The type locality is Shixi of the Qianshan County. The key section is the Huobashan section in Xixiang of the Yiyang County, Jiangxi (117º27'48″, 28º31'18″)

The Shixi Formation is a group of multi-colored sandstone, mudstone, volcanic clastic rock, volcanic lava, a layer of conglomerate occurs at the bottom. It is 275 to 1052 m thick.

The formation yields bivalves Nakamuranaia sp.; insect Ephemeropsis sp., Notocupes sp.; ostracods Rhinocypris jurassica, Darwinula sp., Cypridea sp., conchostracans Yanjiesthera ehulinensis; plant Manica sp., Onychiopsis sp., Ptilophyllum sp., Otozamites klipsteinii, Brachyphyllum sp.

"The age distribution shows that the Daguding Fm, Ehuling Fm, and Shixi Fm of the Wuyi Gr were not continuously upward succeeded but prograded laterally in the Ganzhou Basin (see Section 5.1). The procedure of the progradation could be interpreted as follows: the Daguding Fm was firstly founded, and it is the representative of the earliest volcanic eruption for theWuyi Gr; the Ehuling Fm had been laterally and distally accumulated while the Daguding Fm was succeeded by the persistent volcanism; the Shixi Fm had thereafter been deposited and constructed with pyroclastics and sediments in a further distal basin far away fromcraters. The three formations show different contact relationship in the Xinjiang Basin, where the Daguding Fm may have been underlain by the Ehuling Fmand Shixi Fm, and the latter two formations were mostly coeval." [quote from Li, Xianghui et al., 2019. "Refined chronostratigraphy of the late Mesozoic terrestrial strata in South China and its tectono-stratigraphic evolution", Gondwana Res. 66: 143-167. https://doi.org/10.1016/j.gr.2018.09.006]