塔里木盆地的构造演化

TECTONIC EVOLUTION OF THE TARIM BASIN

从地震大剖面显示,塔里木盆地发育为手风琴式的演化史。大体上形成有3层“断—坳”结构:①震旦系的“断”,古生界—三叠系的“坳”;②侏罗系的“断”,上白垩系的“坳”;③古近系的“断”,新近系的“坳”。断陷与坳陷分别由拉张与挤压应力场所致,这种应力场的变化是由相邻洋壳板块俯冲倾角由小到大的变化所引起的。由于地壳的多旋回运动,多次发生构造沉积演变,构成了多套生储盖组合,多领域、多种圈闭类型的油气藏,从震旦系—古生界—中生界—新生界,各断陷—坳陷结构的盆地都有可能形成油气藏的地质条件。

Seismic sections show that the Tarim basin evolved in an “accordion” way. Generally, the basin has three “fault-depression” structures: ① Sinian fault, Paleozoic-Triassic depression; ② Jurassic fault, late Cretaceous depression; and ③ Palaeogene fault, Neogene depression. These faults and depressions were made respectively by tension and compression stress fields, and changes of such stress fields were due to the changes of subduction dips from small to large of the neighboring oceanic crust. Due to the multicyclic movements of the crust, tectonic sedimentary changes took place frequently. As a result, sets of oil generation, reservoir and capping associations were produced. From Sinian to Paleozoic to Mesozoic and to Cenozoic, each fault-depression structure may have its own geologic conditions to form oil-gas pools.