Xipo Fm

Jiang Chunfa et al. named this formation in 1966. The named section is located between Niejiawan and Pipaxia, Liangdang County, Baoji-Chengdu Railway. In 1960, the Shaanxi Regional Survey Team created the name “Liufengguan Group” to represent the Silurian in Feng County, Shaanxi Province. In 1963, Jiang Chunfa and others discovered the early Triassic ammonoids for the first time in this set of strata, thus changing the age to the Early Triassic, and in 1966, they divided this group into Xipo Fm and Renjiawan Fm from bottom to top. In 1968, the 15th Division of the Survey Team of Shaanxi Geological Bureau used these two names for the first time, and the Xipo Fm and Renjiawan Fm were used to represent the flysch deposits of the early and late Early Triassic in Fengxian area, Shaanxi Province. In 1979, Jiang Chunfa et al made a detailed division of its sedimentary formation.

Synonym:

It is a sedimentary cycle composed of gray thick layer and middle layer calcareous siltstone, calcareous slate and gray thin layer limestone, siliceous limestone and argillaceous banded limestone. There is fine sandstone, brecciated limestone and submarine landslide layer in some part, with oblique bedding and pictographic mold, and the rhythm is obvious. Thickness is 1373 m.

Ammonoids: Lytophiceras sp.

This formation is a turbidity current deposit.