伸展型复合盆山体系下江汉盆地中、新生代幕式沉降与迁移
Mesozoic-Cenozoic Episodic Subsidence and Migration of Jianghan Basin in Extensional Composite Basin-Mountain System

江汉盆地与周缘山系构成伸展型复合盆山体系，周缘山系的差异隆升可能与江汉盆地沉降、迁移和构造变形具有协同演化关系.通过沉降史模拟，表明江汉盆地裂陷期具有幕式特征，可分为3个裂陷幕：裂陷Ⅰ幕发生在晚白垩世，裂陷Ⅱ幕发生在古新世沙市组-早始新世新沟咀组沉积时期，而裂陷Ⅲ幕则发生在早始新世荆沙组-渐新世荆河镇组沉积时期.沉降中心发生有规律的迁移，裂陷Ⅱ幕沉降中心由裂陷Ⅰ幕条带状、多方向、多中心向西迁移到江陵凹陷，裂陷Ⅲ幕沉降中心向东迁移到潜江凹陷.伸展型复合盆山体系下盆地沉降中心有规律的迁移可能受多种因素的影响，其盆地周缘山系的差异隆升与盆地沉降中心的迁移显示出此消彼长的响应关系.晚白垩世末至始新世初盆地东缘山系(大别造山带、幕阜山和鄂东冲断带)剥蚀隆升，盆地沉降中心向西迁移.始新世末至渐新世盆地西缘山系(黄陵隆起、湘鄂西冲断带)抬升，盆地沉降中心向东迁移，沉降中心呈现出远离隆起端的“背离式”迁移.地幔底辟作用的差异性变化控制着盆地沉降中心的迁移.
An extensional composite basin-mountain system is formed by Jianghan basin and its peripheral mountains, and there might be coupling relationship between the basin and orogenic belt. In this study, the subsidence history analysis shows the feature of episodic subsidence in Jianghan basin, which is divided into three rifting stages: Episodic Ⅰ Late Cretaceous, Episodic Ⅱ Paleocene ShashiEarly Eocene Xingouzui phase and Episodic Ⅲ Early Eocene Jingsha-Oligocene Jinghezhen phase. The subsidence center migrated regularly,and it moved to Jiangling depression in the Episodic Ⅱ and Qianjiang depression in the Episodic Ⅲ. The regular migration of subsidence center in the extensional composite basinmountain system might be affected by many factors. In the meantime, it displays the response relationship between the migration of subsidence center and the peripheral mountains. The east mountains (Dabie orogen, Mufushan massif and Edong fold-thrust belt) uplift as the subsidence center migrates westward. And west mountains (Huangling massif and Xiang'exi fold-thrust belt) uplift as the subsidence center migrates eastward. In addition, the subsidence center shows the character of “deviation type” which migrates farther away from where the orogen uplifts. Meanwhile, the migration of subsidence center may also be affected by the changes of mantle diapir