中国南方二叠纪层序地层时空格架及充填特征

据华南二叠纪不同沉积盆地层序地层区域分布、纵向演化及其充填特征分析研究,初步建立了上扬子克拉通-右江盆地-钦防盆地、中扬子克拉通及全区的层序地层时空格架模型;提出层序充填可分为两个阶段:早二叠世碳酸盐缓坡-台地层序充填阶段,晚二叠世陆源碎屑为主与火山碎屑相混层序充填阶段;认为全区二叠纪四个Ⅰ型层序受控于构造隆升事件,晚二叠世层序TST普遍发育火山碎屑沉积,古陆边缘HST或少量SMT/LST大多由三角洲沉积体系进积叠加而成,上扬子克拉通及右江地区的生物礁以海侵和高位型为特色。

Patterns and Fills of Permian Sequence Stratigraphy in South China

The patterns of thime evolution and space distribtion of the Permian sequence stratigraphy in South China,which are recognized as in the paper by Wang et al.in this period of the journal,are well confined by the research on sequence fills of the eleven depositional sequences. It is proposed that two stages of depositional sequence fills can be classified,i.e.,(1)Fills by carbonate ramp and platform depositional sequences could have been undertaken during early Permian,into which sub fills could have been done by carbonate ramp and platform depositional sequences respectively.(2)Fills could have been completed by depositional sequences in dominant terrigenous clastics environments mixed by volcanic clastics during late Permian.It can be subclassified into two subdivisions as sediments with coal in wet climate in the Wujiaping Stage and as coarse clastics in extensional pull aparting faults during the Changxing Stage. It is supposed that the four type I sequence boundary surfaces in Permian could be directly relevant to the tectonic upwarding events.The basal boundary surface of the S 1 might have been controlled by the Yunnan Movement (or named of Guizhou Guangxi Movement) that had taken roles in the middle Yangtze Craton and on the western margin of the Cathayan Craton.The boundary surface of the S 6 might have been in fluenced by the first episode of the Dongwu Movement (also called Dachang Movement) which had acted similar areas as the S 1 The S 7 boundary surface had ever widespread related to the Dongwu Movement all over the South China during the gap between the Early and Upper Permian.And the boundary surface on the S 1 base might have been under impacts by the Guiyang Movement almost the yangtze Craton. One of the most characteristically depositional sequence fills is volcanic clastics in some horizons in the TST of late Permian,during which a few horizons of the transgressive systems tracts (TST) had ever been filled by volcanic clastics.There is a typical sequence pattern of sedimentary facies in the TST with volcanic clastics.It is common that the sequence from calsiclastic turbidite facies to volcanic turbidite facies,to marlstone facies in the TST.The other is the delta system along the margins of paleolands.Most of the delta systems constitute the high systems tracts (HST),and/or few shelf marginal systems tracts (SMT) or lowest systems tracts (LST). Reefal fills can be found in the upper and middle Yangtze Cratons and Youjiang Basin,and four types of reefal fills can be differentiated in the depositional sequence fills.They are TST type,HST type,LST type,and SMT type,in which TST type and HST type are predominant along the synsedimentologicall strike slip faults.Reefs in high abundance and diversity filled in the TSTs had been lived in deep water,mostly in slope,deep ramp,and/or inter platform.Reefs in the HSTs are of low abundance and diversity of species and community,and they had been lived in shallow sea such as carbonate platform,shore,shelf and isolated platform