TARIM UNDERTHRUST BENEATH WESTERN KUNLUN: EVIDENCE FROM WIDE-ANGLE SEISMIC SOUNDING

Abstract

This paper describes the results of a wide-angle seismic profile, over 700km long, across the southern margin of the Tarim Basin. A crustal structure that best fits the observed data, that tests and verifies the earlier discovery that the crystalline basement dips southward from the area of the petroleum industry seismic reflection profiling and geological investigation is presented. The profile also reveals that the Moho dips southward beneath the southern Tarim, at an angle in concordance to that of the crystalline basement. This result is thought to be the first evidence for the underthrusting of the Tarim crust beneath the western Kunlun. Additional evidence of underthrusting is that the relatively weak western Kunlun crust has contracted, and expressed by a lower crust, which is more than 20km thick, with an uplift of the Kunlun basement, accompanied by northward-directed thrusts.