摘要
河套盆地经历40余年勘探，近期获得重大突破，吉华2X井和松5井高产油流证明临河坳陷内中-新生代层系具有较大的勘探潜力，因此开展中-新生代盆地构造演化研究，对分析沉积充填过程与圈闭形成条件具有借鉴意义。通过野外露头调查、岩心观察、地球物理资料解释及构造演化阶段分析等综合研究认为：临河坳陷及周边地区中-新生代发育挤压、伸展、走滑和反转等多种构造变形样式，经历了挤压拗陷（早白垩世李三沟组沉积期）、拗-断转换（早白垩世固阳组沉积期）、隆升剥蚀（晚白垩世—古新世）、弱断陷（始新世—渐新世）、强烈断陷（中新世—上新世）和走滑改造（更新世—全新世）等多期构造演化阶段，盆地类型属于多旋回叠合盆地。建立了早期差异挤压、晚期差异伸展叠加盆地成因模型。
Abstract
A major breakthrough, marked by two high-yield wells (Jihua 2X and Song 5), has been made recently in the Linhe Depression of the Hetao Basin after more than 40 years of exploration, thus revealing the great hydrocarbon potential of its Mesozoic-to-Cenozoic strata.A study on the tectonic evolution of the basin from the Mesozoic to Cenozoic may be of great contribution to the analysis of the deposition process and conditions for forming oil/gas traps.As a result, an integrated analysis of field outcrops, cores, geophysical data, and structural evolution of the basin was carried out and shows that a variety of structural deformation patterns are developed in the Linhe Depression and its surrounding areas from the Mesozoic to Cenozoic, including compression, extension, strike-slip, and inversion structures.The study area thereby experienced multiple-stage evolution from compressional depression (during the deposition of Lisangou Formation in the Early Cretaceous), depression-to-faulting conversion (during the deposition of Guyang Formation in the Early Cretaceous), uplifting and denudation (during the Late Cretaceous to Palaeocene), to weakly rifted depression (during the Eocene to Oligocene), strongly faulted depression (during the Miocene to Pliocene), and strike-slip transformation (during the Pleistocene to Holocene).The basin belongs to the multi-cycle superimposed type.And a genetic basin model was established to incorporate an early differential compression and a superimposition with late differential extension.
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