Research on fossil plants of Late Triassic Shangtian Formation in the Helan Mountain

In this paper, the fossils of the Shangtian Formation in the Helan Mountain area were studied, and 14 species of 12 genera were identified. In combination with the data provided by previous researchers, there are 35 species of 20 genera in the Shangtian Formation, which include Filicopsida and Spermatophyta of 19 specie in 9 genera, Cycadopsida of 6 species in 4 genera, Sphenopsida of 4 species in 1genus, Coniferae of 3 species in 3 genera, Ginkgopsida of 2 species in 2 genera. Many plants have the characteristics of Danaeopsis-Bernoullia flora belonging to northern provinces of China, but some species of southern provinces in China and Cycadopsida were also found in this flora. Studies show that the Helan Mountain was dominated by a semi-arid subtropical continental climate in the late Late Triassic, which was developed towards humid heat.