Abstract: Through the studies of surface geology and interpretation of great number of high-quality seismic sections, structural type of the southwest depression in Tarim basin may be divided into two major types, six subtypes and ten small types. The major types are: (1) basement rolling-in type, including basement thrust, strike-slip torsion, thrust-torsion complex and basement flexure: (2)caprock detachment type, involving tension fault depression, dual thrust, imbricate thrust, detachment anticline, gravity sliding and bend-faulted anticline. An oil reservoir has recently been discovered in detachment anticlines and the upper of dual structure. Therefore, it is estimated that various detachment structures, folded fault systems associated with torsion structure, basement flexure structure and basement rolling-in anticline are prospective area for oil and gas exploration in Tarim basin.

Key words: Tarim basin, Structural type, Basement rock, Caprock, Oil and gas exploration