安徽巢湖石炭系和州组地层学和沉积学研究新进展

石炭纪—二叠纪旋回层是由晚古生代冈瓦纳冰川的冰期与间冰期的交替而造成的海进—海退循环沉积的层序,出现在全球尤其是北半球的很多地区。根据岩石微相和沉积构造特征,安徽巢湖凤凰山石炭系和州组,可识别出5个海进—海退沉积序列;根据和州组中有孔虫的分布特征,自下而上可分为5个有孔虫带,确定其地质年代是从维宪期晚期到巴什基尔期早期。这5个海进—海退沉积旋回,与华南其他地区和欧美地区的同时代地层中出现的大的海进—海退事件基本一致。

BIOSTRATIGRAPHIC AND SEDIMENTOLOGICAL PROGRESS OF THE CARBONIFEROUS HEZHOU FORMATION AT CHAOHU,ANHUI PROVINCE

Late Paleozoic cyclothems are transgressive-regressive depositional sequences in the Carboniferous and Permain shallow marine successions and represent glacial-interglacial cycles during the Gondwana glaciation.However , few studies have been carried out on the cyclothems outside North America and Europe.The Fenghuangshan section , which is located at Chaohu City of Anhui Province and belongs to the Lower Yangtze Block , was selected for a case study to evaluate possible cyclothemic deposits in Paleotethyan region.The Hezhou Formation is composed of shallow-marine carbonates with frequently and cyclically intervening siliciclastic rocks and / or exposure surfaces.A detailed analysis of microfacies and sedimentary structures of the Hezhou Formation reveals five transgressive-regressive depositional sequences in 29.6-m-thick strata.The Hezhou Formation consists of five foraminiferal zones indicating an age from the late Visean to early Bashkirian.The five transgressive-regressive depositional sequences can be correlated with those in other areas of South China and even in Euramerica.