川滇黔桂地区二叠纪不同成因盆地层序地层模型

Sequence Stratigraphic Characteristics of the Permian, Sichuan-Yunnan Guizhou-Guangxi Region

通过不同类型沉积盆地层序界面性质、层序类型、结构、组成、完整性、对称性以及层序发育特征和控制因素研究表明，不同成因沉积盆地，其层序内部构型及成因格架各异。克拉通盆地层序发育主要受全球海平面变化及碳酸盐自旋回控制，ＬＳＴ以陆上暴露不整合面及其上风化残积相为特征，ＴＳＴ以海侵上超不整合面上相对薄的超覆型退积准层序组为特色，ＨＳＴ表现为厚层加－进积丘礁滩组合；对于被动陆缘裂谷盆地，主控因素包括全球海平面变化和同沉积断裂活动，ＬＳＴ期，孤台以陆上暴露不整合面及残积相为标志，台盆表现为水下间断不整合面及上覆混屑浊积岩，ＴＳＴ以台盆硅灰岩－硅岩退积准层序组不断向斜坡和孤台上超为特征，ＨＳＴ期，孤台以加积－进积丘礁滩组合为主，台盆为加积型钙屑重力流沉积，弧后裂谷盆地层序特征与被动陆缘裂谷盆地相似，但其台盆加深加宽，层序以硅质岩及火山碎屑浊积岩为主，揭示层序发育主要受同沉积断裂活动、全球海平面变化及火山活动控制；被动陆缘走滑盆地层序发育主要受控于不同沉积断裂活动及全球海平面变化，层序组成以放射虫硅质岩和深水泥岩为主；前陆盆地ＬＳＴ以造山侵蚀不整合面及盆底扇沉积为特征，ＴＳＴ表现为巨厚层浊积扇－扇三角洲弱进积－弱退积充填型准?

Based on plate location, crust type, sedimentary association and volcanism etc, the Permian in Southwest China can be classified into five types of sedimentary basins, i.e., cratonic basin, continental marginal rifting basin, retroarc rifting basin, continental marginal strike-slipping basin and foreland basin, in which both nature of sequence boundary surface and type, texture, composition, completeness, symmetry, development and controls of sequence stratigraphy have been studied in detail in this paper. The author suggests that the genetic framework and internal architecture of sequence stratigraphy of genetically distinct sedimentary basins are obviously different. Aa far as cratonic basin is concerned, sequence development is predominently controlled by eustatic sea level and carbonate autocycling. LST is characterized by eluvial facies above subaerally erosional unconformity, TST by relatively thin retrogradation-overlapping parasequence sets above transgressive onlapping unconformity and HST by thick aggradation-progradation mound-reef-shoal association. The eustatic sea level change and synsedimentary faulting are the main controls of sequence, within continental marginal rifting basin. LST possesses feature of subaearialy exposed unconformity on isolated platform and mixed clastic turbidite above submarine hiatus unconformity in interplatform basin, TST of retrogradation parasequence sets of onlapping isolated platform, and HST of aggrasdation-progradation mound-reef-beach assemblage on isolagted platform and aggradation parasequence sets of carcalceous gravity-flow sediments in interplatform basin. Sequence characteristics of retroarc rifting basin is similar to those of continental marginal rifting basin, but a great quantity of pyroclastic turbidite develops in interplatform basin, reflecting main sequence controls are synsedimentary faulting, eustatic sea level change and volcanism. Synsedimentary faulting and euatatic sea level change serve as predominent controls in continental marginal strike-slipping basin, of which sequence stratigraphy is mainly composed of radiolaria siliceous rock and deep-water shale. As for foreland basin, LST is characterized by orogenic erosional unconformity and overlaying basin-floor fan sediments and TST of filling parasequence sets of turbidite-fan delta sediments, HST possesses intensive progradation parasequence sets formed by fan delta-alluvial fan plain sediments,demonstrating that the main sequence controls are orogeny and related provenance supply, and then relative sea-level change.