塔里木盆地及邻区寒武纪——三叠纪构造古地理格局的初步重建

塔里木陆块寒武纪——三叠纪主要经历了从东冈瓦纳大陆西北缘裂解、到向劳亚大陆聚合的演化过程,北部长期为被动大陆边缘环境,南部主要为裂谷、持续裂解以及漂移过程中陆块地体增生拼合,主要为弧后前陆盆地或隆起。塔里木盆地一级层序地层、区域不整合事件、次级构造单元的构造演化等,与板块边界上构造活动及其板块运动轨迹的变化具有明显的一致性,板块边界上的挤压造山活动,造成盆地隆升以及盆地岩相古地理格局的剧烈变化。引发塔里木盆地早二叠世大火成岩省的地幔柱活动,垂向上也造成石炭系穹隆状剥蚀抬升。塔里木叠合盆地的形成是小陆块上不同时期不同盆地类型复合的产物,而在世界其他大板块上,它们在横向上可能处于不同位置,不会发生垂向叠合,而以不同时代的不同盆地出现。塔里木陆块较全球典型克拉通盆地规模小,在与周边陆块碰撞汇聚时受改造强烈,构造变形程度大并由陆块边缘向陆块内扩展,南、北两侧陆块边界上的强烈构造作用易于对整个盆地产生强烈影响,发育挤压期盆地隆起和前陆盆地等。

Preliminary Reconstruction of Tectonic Paleogeography of Tarim Basin and Its Adjacent Aeras from Cambrian to Triassic, NW China

Tarim basin rifted from the northwest margin of East Gondwana supercontinent and drifted to Laurentia supercontinent during the period from Cambrian to Triassic. While its north margin is passive continental environment and south mainly is back arc foreland basin or uplift as a result of different blocks or terranes accretion. First order sequences, regional uncomformity events and tectonic evolution of secondary tectonic units in Tarim basin all related to tectonic activity in plate boundary and change of plate motion track. Compressional orogeny along plate boundary caused uplifts in the basin and significant change of lithofacies paleogeography framework. Carboniferous strata were erosioned in dome shape and uplifted by vertical activity of mantle plume, which led to the large igneous provinces in the early Permian. Tarim superimposed basin, product of multi prototype bains in small blocks composited in the different periods, differed from that in the other plates with no vertical composite influenced by variations in the lateral migration. Tarim block is smaller than other global typical craton basins, underwent tectonic reworking intensely because of the collision with adjacent blocks ,such as Kazakhstan/Altyn-Qilian and Qiangtang block, with strong tectonic deformation extending from magin to the inside.