THE LATE TRIASSIC FLORA AND COAL PROSPECTS AT BAOJISHAN,JINGYUAN, GANSU

The fossil flora described in this paper occurs in the Upper Triassic Nanying’er Group in the vicinity of Longfengshan and Baojishan. Jingyuan County, Gansu Province. The flora includes two phyla, Pteridophyta and Gymnospermatophyta, and five classes, Articculatae, Filices, Pteridospermopsida, Ginkgopsida and coniferae. There are a total of 11 genera. According to the elements of the flora and its distribution features, three assemblages may be distinguished: Assemblage Ⅰ: Sphenopteris-Neocalamites, Carnian in age; Assemblage Ⅱ: Danaeopsis-Bernoullia, early and middle Norian in age; Assemblage III: Dictyphyllum-Podozamites, late Norian-Rhaetian in age. The late Norian-Rhaetian stage is an important coal-forming period in the area. The upper sector of the strata of this period, i.e. Beds 12-16, is a zone favourable for coal accumulation. The synclinal structure and paleofluvial areas provide good coal-forming conditions.