塔里木多旋回叠合盆地地质结构特征

塔里木盆地现今的地质构造特征是在长期的地质演化过程中,不同阶段的不同类型的原型盆地复合与叠加的结果。在纵向上,为区域不整合面分隔;在横向上,为大型断裂带切割,因此,表现出纵向分层、横向分块的不均一特征。构造层序的叠置表现出连续、间断或倒序特点,从而出现了新生代前陆坳陷与中生代断陷的叠置,新生代前陆坳陷与中生代断陷、古生代克拉通被动大陆边缘的叠置,中生代边缘坳陷与早古生代边缘坳陷的叠置,中生代断陷在前陆冲断带后缘的叠置,新生代前陆坳陷与古生代克拉通内坳陷的叠置,中新生代隆起与古生界克拉通内坳陷的叠置,新生代前陆冲断带与古生代大陆边缘的叠置等7种样式。沉积盆地的地质结构对盆地内含油气系统的发育与油气分布起制约作用。晚海西期与晚喜马拉雅期是塔里木盆地的关键成藏时期,相应的古隆起、古斜坡与前陆冲断带决定了油气聚集的部位。

Characteristics of Geologic Framework of Multicycle Superimposed Basin in Tarim Basin

The Geologic structures of Tarim Basin nowadays has been resulted from the long geological evolution and the composition andsuperimposition by the different proto-type basins during their different geologic period. It is thus separated vertically by regional unconformitiesand cut horizontally by large-scale fault zones, the outline, as a result, indicates the strong heterogeneities in the geological structures such aslayering vertically and fracturing horizontally.The superimposition of tectonic-sedimentary sequences exhibits such styles as continuous, hiatusand reversion. Basically, there are seven superimposed styles as follows, the superimposition between Cenozoic foreland depressions andMesozoic fault-depressions, the superimposition between Cenozoic foreland depressions and Mesozoic fault-depressions and Paleozoic cratonicpassive margin, the superimposition between Mesozoic marginal depressions and Early Paleozoic marginal depressions, the superimpositionbetween Mesozoic fault-depressions and the hinterland of foreland thrust belts, the superimposition between Cenozoic foreland depressions andPaleozoic intra-cratonic depressions, and the superimposition between Meso-Cenozoic uplifts and Paleozoic intra-cratonic depressions as wellas the superimposition between Cenozoic foreland thrust belts and Paleozoic continental margins.The geologic framework of sedimentary basinhas played an important role in the development of petroleum system and the oil/gas distribution.The late Hercynian and the late Himalayanperiods are the critical moments for oil and gas reservoirs forming in Tarim Basin.The related paleo-uplifts, paleo-slopes, and the foreland thrustbelts has controlled the favorable positions of oil/gas accumulation.