柴达木盆地北缘晚中生代—新生代构造应力场——来自构造节理分析的证据

柴达木盆地的构造演化，尤其是中、新生代的构造演化历史及其影响程度一直存在争议。在冷湖0号、冷湖4号、鄂博梁、结绿素等剖面开展了野外构造节理测量，应用地层恢复技术，分析了柴北缘晚中生代—新生代构造应力场的演化过程。结果表明：晚侏罗世之后，柴北缘主要受东西方向的挤压，这与区域上的研究结果一致；早白垩世北西—南东向的挤压应力可能再次影响了侏罗系；晚白垩世受南北挤压应力的影响，地层隆升遭受剥蚀；始新世下干柴沟期至上新世狮子沟期，柴北缘处于弱活动时期，接受稳定沉积；上新统狮子沟组沉积之后，由于阿尔金山的隆升，盆地北缘主体受北西—南东向应力的影响，涉及地层包括上干柴沟组、下油砂山组和上油砂山组；早、中更新世七个泉期之后，受南北向构造应力场的强烈影响，在狮子沟组、上油砂山组和下油砂山组中都有其分量，较老地层的地表露头中也有记录，这期构造运动对柴北缘油气运聚具有破坏和二次成藏的作用。因此，围绕柴北缘其他地质剖面开展更进一步的构造节理测量和分析工作，对油气资源勘探具有指导意义。

The stress field of Late Mesozoic-Cenozoic tectonics in the northern Qaidam basin, Northwest China: Evidences from the analysis of joints data

The tectonic evolution of Qaidam basin, especial on the Mesozoic and the Cenozoic period, is still in debated. In order to determine the stress field of the northern Qaidam basin and to discuss the tectonic evolution of this area in the Mesozoic-Cenozoic, we carried out joints data measurements from sections of Lenghu No.0, No.4, Eboliang and Jielusu. We then deduced the stress direction applying the strata recovery technique to the different formations. The results suggest that the northern Qaidam basin mainly experienced E-W compression after the Middle-Late Jurassic, which is in accordance with previous results. Following the track on Jurassic strata we can conclude on NW-SE compression since the Early Cretaceous and on S-N compression after the Late Cretaceous which made the strata uplift and denudation. From the Eocene Xiaganchaigou epoch to Pliocene Shizigou epoch, northern Qaidam basin stays in a weak condition and accepts stable deposition. After the deposition of the Shizigou Formation, the NW-SE direction stress which caused by the uplift of Altyn Tagh Mountains, strongly affected the Shangganchaigou, Xiayoushashan and Shangyoushashan formations. Obviously, the strongest stress of N-S direction plays an important role to the Shizigou, Shangyoushashan and Xiayoushashan strata, even to the outcrop of Xiaganchaigou, Lulehe formations and Jurassic layer. This event not only destroys the previous petroleum system of northern Qaidam basin, but also is important to the motion and accumulation of petroleum again. Thus, more work related to joint data analysis of other profiles in northern Qaidam basin need to carry out, and it is signification to guide the exploration of the oil and gas resources in the Qaidam basin.