中国南方二叠纪层序地层划分与对比

对中国南方二叠纪时期不同沉积盆地类型的沉积层序进行了深入研究,综合各种盆地类型的沉积层序,该期可识别11个层序单元(S₁～S₁₁),其中,栖霞、茅口、吴家坪三阶分别含三个层序,长兴阶两个层序,S₁、S₆、S₇、S₁₁为Ⅰ型,其余为Ⅱ型。层序对比显示,上、中、下扬子的层序数量相近,界面特征各不一致,靠近古陆处在P/C、P₁/P₂界线间缺少层序1～2、3～5个不等;华南太平洋构造域影响区层序体系域具HST>TST结构,特提斯域控制区则具HST

Characteristics and Correlation of Permian Depositional Sequences in South China

Permian sequence stratigraphy in different kinds of sedimentary basins in South China is discussed in this paper,which is based on the great geological investigation on a large scale and analyses of previous works. Eleven depositional sequences S₁ S₁₁ are recognized in Permian in most Parts of South China,in which the S₁ S₃,S₄ S₆,S₇ 9 are determined in Qixia Stage,Maokou Stage and Wujiaping Stage respectively,and the S 10 S 11 are limited in Changxiny Stage.of them,the depositional sequences S₁,S₆,S₇,S₁₁ have a feature of the type-Ⅰ sequence boundary surface,and others have a feature of the type-Ⅱ surface.S 1 or S 2 depositional sequences could not be deposited somewhere between the Carboniferous and Permian,also S₃ or S₅ could not be between the Lower and Upper Permian. There are variable indicators for distinguishing the boundary surface types in all of the upper,middle and lower Yangtze Craton accoriding to comparison in South China.Clay layers with high Fe and Al,paleokarst fills with meteoric dolomite,and dolomitic caps are easily found on both type-Ⅰand type-Ⅱ boundary surfaces in the upper Yangtze Craton and its margins,and isolated carbonate platform.There are little exposure markers on boundary surfaces of most depositional sequences in the middle and lower Yangtze Craton except the basal boundary surface of the S₇ in the middle craton and the S₉ in the lower eraton.We think it might be related to the different tectonic settings of sedimentary basins. Loss of depositional sequences is also characterized by another way. S₃ to S₅ depositional sequences are difficult to be found out in most basins nearby paleocontinents.One example is that S₄ or S₅ in the S₇ S₁₁ could not be tracked at Hechi,Guangxi,and Xishui,Guizhou in the north of the Daxin paleocontinent.It is proposed that this could be the result of the Dongwu Movement,which leaded to the formation of Daxin Paleocontinent,South Yangtze River Paleocontinent and Yunkai Paleocontinent. It is supposed that the HSTTST pattern of depositional sequences in Yangtze Craton and its margins.western Cathayan Craton margin was influenced by tectonism of the Pacific tectonic field.And the HSTTST pattern in Youjiang Basin and Qingzhou-Haifang Strike-slip Basin,and host Cathayan Craton to a great extent was controlled by the Tethys tectonic field. It can be correlative on the amount,hierarchy,and boundary surface of the depositional sequences in the Lower Permian among North America,Russia,and South China,but not be the depositional sequences in the Upper Permian among them.It is inferred that the divergence of Pangea could be responsible for the situation.Any of the depositional sequences in South China has no analogues in North China.