The rhombic basins of the Meso-Cenozoic in en echelon arrangement area kind of tensile tectonics

i. e.

pull-apart basins in Hexi Corridor region.The evolution has undergone three stages: 1.During the Early-Middle Jurassic

the crust was activated under the tensile stress process and the fault-blocks broke and subsided inharmoniously along NWW stretched fault zone. 2.In the Late Jurassic-Early Cretaceous

the basins intensely tensioned.The NE trending fault-subsided basins occured in the overlaying and displacement sections between boundary slide-faults because the slide faults sliped to result in lateral tensile stress

thus forming a tectonic framwork in the alter-nation of depressions and uplifts. 3.Since the Cenozoic

the basins were influenced by compreso-shear stress caused by the collision of the Indian plate and the pulling-apart process was stopped. The fault-subsided basins then cbanged into depressions. forming the structures and topographic landscope of north and south zoning. The types or sedimental facies

structural traps

oil-gas pools attd their distribution directions may vary in different evolution stages

but they are controlled by the faults. So the most favourable way for oil exploration is tofind oil traps along these faults.