塔里木盆地北缘构造演化及其含油气远景

塔里木盆地北缘自中元古代以来,经历了6个演化阶段:(1)新疆古板块发育时期(Pt₂—∈₁);(2)被动大陆边缘形成时期(∈₂—O₁);(3)塔里木古板块向伊宁—中天山古板块俯冲时期(O₂—C₁):(4)碰撞前陆拗陷时期(C₂—P);(5)碰撞山前拗陷时期(T—N₁);(6)碰撞复活山前拗陷时期(N₂—Q)。塔里木盆地北缘可分为塔北隆起带和库车—拜城掩冲断褶带两个次级构造单元。塔北隆起带是一个较高的基岩隆起,上古生界遭到严重剥蚀,发育古潜山和背斜构造,且紧邻生油凹陷,油气前景较好。库车—拜城掩冲断褶带具有上、下两层结构,上层由中新生界构成,以一系列逆掩断层和褶皱为特征;下层由古生界构成,被动陆缘型沉积建造掩伏于南天山推覆体之下,形成了丰富的油气资源。本区除中新生界含油气外,预计古生界还具有大量的气资源。 

TECTONIC EVOLUTION AND OIL AND GAS POTENTIAL IN NORTHERN TARIM BASIN

The northern Tarim Basin has undergone 6 evolutionary phases since the middle Proterozoic:1)The development of Xinjiang paleoplate (Pt₂-∈₁); 2)The formation of the passive continental margin (∈₂-O₁); 3)The subduction of the Tarim paleoplate to the Yining-Middle Tianshan paleoplate (O₂-C₁); 4)The colliding foreland depression period(C₂-P); 5)The depression period of colliding predmount(T-N₁); 6)The colliding reactivated predmount depression(N₂-Q). The northern Tarim Basin can be subdivded into 2 tectonic parts: i.e. the northern Tarim uplift belt and the Kuche-baicheng thrust fold belt. The former is a high basement uplift in which Paleozoic strata was erosed seriously, and ancient buried hills and anticlines were well developed. It is the most promising zone owing to its bordering on the Manjiaer and Ku-che oil generation depressions.The latter consists of a double-deck structure, the upper is characterized by a series of thrust faults and folds in the Meso-Cenozoic strata; the lower is made up of the Paleozoic strata. The sedimentary formation of the passive continental margin overridden by the south Tianshan nappe is important source rocks. Besides the oil-bearing Meso-Cenozoic strata, it is expected that there are a great amount of Paleozoic gas resources in this zone.