| Abstract: | One hundred and thirteen species of spores and pollens belonging to 58 genera were found from 66 core samples taken from two boreholes of the Early and Middle Jurassic deposits in the Qiquanhu coal-field of the Turpan Basin, Xinjiang have been investigated in this paper. Two of the species are described as new. Three sporo-pollen zones from lower to upper are described as follows: Sporo-pollen zone Ⅰ (equivalent bed: Badaowan Formation) . The pteridophytic spores are slightly more abundant than the gymnospermous pollen in this assemblage. The most abundant spores are Cyathidites minor, C. australis and Undulatisporites pflugii, U. taenus and so on. The second important fern spores are Osmundacidites, Lycopodiumsporites, Apiculatisporis and Duplexisporites. The most important gymnospermous genus is Cycadopites which ranks highest in the assemblage and includes C. nitidus and C. typicus.The other gymnospermous pollen include Classopollis, Pinuspollenites, Protoconiferus Piceites. Besides, there are a few pollen grains of Taeniaesporites and Chordasporites surviving from the Late Triassic in this assemblage. The present assemblage may be compared with the Early Jurassic sporopollen assemblage from the Daling Formation of the North-East Guangxi. Therefore, the Badaowan Formtion may be referred to Early Jurassic in age, probably Early Lias. Sporo-pollen zone Ⅱ (equivalent bed: Sangonghe Formation) In this assemblage the gymnosperms are predominant.Of them, Podocarpidites and Pinuspollenites increase obviously, and Quadraeculina and Protoconiferus are common. Few surviving elements are observed. The most abundant spores are those of Cyathidites, and the particularly abundant pollens are those of Cycadopites, This assemblage may be compared with the Late Lias sporo-pollen assemblage from the Fuxian Formation of the Northern Shangganning Basin. Therefore, the Sangonghe Formation should belong to Early Jurassic, probably Late Lias in age. Sporo-pollen zone Ⅲ (equivalent bed: Xishanyao Formation). The contents of the spores and pollens are almost equal in this assemblage. Cyathidites and Cycadopites are the most important spores and pollen. Osmundacidites and Quadraeculina are common. Neoraistrickia, Lycopodiumsporites and Eucommiidites troedssonii are present. Ancient striate bisaccate pollen disappears. The characteristics of this assemblage show some resemblances to those of the Middle Jurassic Yanan Formation in Chongxin county of Gansu province. So the Xishanyao Formation should belong to Middle Jurassic. |
