Late Permian Jiefangcun Flora From Hunchun Of Jilin, China

Angara floras are mainly distributed in the northern and northeastern China, covering the region of the Heilongjiang, northern Jilin, Inner Mongolia, to the Ningxia-Tianshan Mt of Xinjiang. Tectonically, the region bearing the Angaran floras is situated in the southern and southeastern edges of the Siberian Plate.This thesis in the first systematic report of the Jiefangcun flora from the Jiefangcun of Hunchun, China, and newly describe 30 species of 22 genera (including 2 new species). Based on the characters of the floristic assemblages, the author considered that the Jiefangcun flora is dominated by the Angaran taxa such as Paracalamites, Prynadaeopteris, Comia, Iniopteris, Zamiopteris, Noeggerathiopsis etc., but mixed with some Cathaysian elements e. g. Lobatannulaira, Schizoneura, Taeniopteris etc. The age of this flora is assigned to Late Permian according to the stratigraphic ranges of the known taxa of the flora and the comparisons of it with the similar floras home and aboard.Based on the floristic characters, the author discussed on the reconstruction of the paleoclimate implied by the flora, and considered that the Hunchun area was probably in temperate climatic area during the Late Permian, and the climate was more mild and humid than the inland areas of Angara Land, due to the Hunchun area was closer to the sea. Phytogeographically, the division line between the Angaran- and Cathaysian Floristic regions, in the eastern Jilin is along Yanji-Tumen-Hunchun, and extending to Vladivostok of Russia, and this phytogeographical line probably is corresponding to the suture line between Siberian Plate and Sino-Korean Plate.The research work reported in this thesis provides new data for the study of Late Permian Angaran flora in Northeast China, and it would also be more significant for the study of the paleogeography and paleoclamite during the Late Permian time in the studied areas.