Paleozoic Structural Deformation of Bachu Uplift,Tarim Basin of Northwest China:Implications for Plate Drifting

摘要

Based on high-resolution 2D seismic profiles,the Paleozoic structural deformation char-acteristics of Bachu （巴楚） uplift of northwestern Tarim basin,NW China,are exhibited in this article. The deformation happened during three main geological periods:the end of Middle-Late Ordovician （O2-3）,the end of Early-Middle Devonian （D1-2）,and the end of Late Permian （P2）. In the Bachu uplift,there developed a series of NW-trending thrust faults and imbricate structures due to the effect of the NW-SE compression stress towards the end of Middle-Late Ordovician （O2-3） （middle Caledonian movement）,and there developed some NNE-trending thrust faults and fault blocks under the control of the NEE-SWW compression stress at the end of Early-Middle Devonian （D1-2） （early Hercynian movement）. However,at the end of Late Permian （P2） （late Hercynian movement）,some NE-trending thrust faults and associated folds developed as a result of the NE-SW compression stress. The first-stage （O2-3） deformation is obviously more violent than those of the latter two stages （D1-2and P2）,which implies that the Tarim plate drifted quickly to the north at around the same time basin.