干旱区生态环境知识资源中心

The Kareim Basin covers an area of 370 km(2) southwest Of Quseir. It is filled with Hammamat sediments and encircled with ophiolites, tectonic melange, metavolcanics, metavolcaniclastics and granites. In the northeast and west, the basin is delimited by thrust and reverse faults whereas normal faults delimit the northwestern and southeastern boundaries. Pull-apart tectonics associated with major NW-SE left-lateral strike-slip faults was responsible for the basin opening. There are indications that syndepositional tectonics occurred during basin formation. The upward grain size variation of the sediments proposes a gradual change from extension to compression. In addition to an external ENE-WSW to NE-SW horizontal compressive stress, the heat-producing contents in the elastic sediments and the high fluid pressure in the basin contributed to heating and strain softening of the underlying lithosphere and facilitated the inversion. The basin center was uplifted and small marginal basins were formed. The steep strike-slip and normal faults were kinked and undulated, and the low angle and kinematic favorable faults were reactivated as reverse faults and thrusts. NW-SE and NE-SW folds were formed in different scales and geometries. The degree of basin inversion can roughly be expressed by the calculated shortening amount that ranges from 20 to 76 %. Different degrees and types of deformation were identified on both mesoscopic and microscopic scales.