1.Chinese Academy of Geological Sciences,Beijing.100037 2.Chengdu Institute of Geology and Mineral Resources,Chengdu.610081,Sichuan 3.Key Laboratory for Sedimentary Basin and Oil and Gas Resources,Ministry of Land and Resources,Chengdu.610081,Sichuan 4 China University of Geosciences(Beijing),Beijing.100083
Abstract：The turn from the early to the late Katian of the Late Ordovician is considered to be a key point during the history of sedimentary evolution and basin-mountain conversion. At that period,almost all of the carbonate sediments changed into clastic sediments in southern Sichuan-northern Guizhou Provinces. Therefore, the research on sedimentary characteristics and lithofacies palaeogeographic transition has an important significance on recognizing sedimentary evolution and basin-mountain conversion. In order to reveal the change of lithofacies palaeogeography at this turning point,two lithofacies palaeogeography maps of the topof Jiancaogou Formation of the early Katian and the bottom of Wufeng Formation of the late Katian are mapped with the method of sequence lithofacies palaeogeography. The early Katian is divided into seven palaeogeographic units, i.e., pelaeouplift,exposed zone, denuded zone, tidal flat,restricted platform,open platform and shoal;and the late Katian is divided into pelaeouplift,tidal flat,shallow shelf,deep-water shelf and shoal. By the means of sequence lithofacies palaeogeography,the exposed zone and its distribution range is restored for the first time and the evolution process of lithofacies palaeogeography at the turn of the early-late Katian is revealed more clearly.
Chen Chao,Mou Chuanlong,Liang Wei et al. Lithofacies palaeogeography of the early Katian and lateKatian of Late Ordovician in southern Sichuan-northern Guizhou Provinces[J]. JOPC, 2014, 16(5): 641-654.
