关键词: 海侵—海退层序, 上古生界, 贵阳乌当剖面

Abstract:

Located at the oldland margin from the Devonian to the Carboniferous, the Devonian System at the Wudang section includes the Mangshan Group clastic rocks and the Gaopochang Formation dolomites, and can be grouped into 5 thirdorder sequences.The Carboniferous System to the Permian Chuanshanian Series includes the Xiangbai, the Jiusi, the Shangsi, the Baizuo, the Huanglong, the Maping and the Liangshang Formation,which can be divided into 5 thirdorder sequences. The Xiangbai Formation and the Liangshan Formation  are constituted by coalmeasures, the other formations are marked by carbonates. Compared with the coeval strata in the southern part of Guizhou and the Guangxi area that are characteristic of the integrity records of strata (the Devonian System can be divided into 13 thirdorder sequences and the Carboniferous to the Permian Chuanshanian Series can be grouped into 6 thirdorder sequences), many thirdorder sequences from the Devonian to the Permian Chuanshanian Epoch are absent. Therefore, the Wudong section of the Devonian System to the Permian Chuanshanian Epoch is of a typical example that the hiatus is larger than the deposits, which might be resulted from the stronger response of regression than that of transgression. As the result of the largescale and slowspeed transgression in the transitional period from the Carboniferous to the Permian, the study area together with the adjacent areas became a sea area. This transgression is genetically related to the thirdorder rise of sealevel changes of the SQ19. Therefore, divisions of thirdorder sequences of the Permian Yangsingian and Lepingian are similar to those in the southern part of Guizhou as well as in Guangxi.

Key words: transgressive-regressive sequences, the Upper Paleozoic, the Wudang section in Guiyang