藏北羌塘中部中更新世以来构造活动的证据

在西藏1∶5万双湖区戈木日东部地区4幅区域地质调查期间，对羌塘中部大沙河泥火山群、河流构造阶地、活动断层进行了详细的野外调查，查明泥火山60个，获得的2个泥火山喷出物热释光年龄分别为151.97ka±12.92ka和10.76ka±0.91ka，表明泥火山群自晚更新世至早全新世存在多次喷发活动。大沙河实测剖面显示，大沙河存在Ⅱ级河流阶地，3次新构造活动。获得的6个热释光年龄分别为中更新世（167.17ka±14.21ka）、晚更新世（113.27ka±9.63ka、83.84ka±7.13ka 、75.47ka±6.41ka、42.22 ka±3.59ka）和全新世（7.61ka±0.65ka）。结合大沙河流域特殊的泥火山-断层构造组合，认为中更新世以来大沙河地区受北西西向活动断层的控制，经历了3次阶段性差异隆升与强烈剥蚀。

Evidence of tectonic activities happened since the Middle Pleistocene in central Qiangtang,northern Tibet,China

A detailed field geological survey of Dashahe mud volcano group, river terrace structure and active faults was included in the 4 sheets Eastern Gemu Mountain area, Shuanghu Region during the 1∶50000 field investigations, during this time, we have identified 60 mud volcanoes, of which two TL age were 151.97 ± 12.92ka and 10.76 ± 0.91ka, which indicated that there were a few eruption events from Late Pleistocene to Middel Pleistocene. Measured Dasha River section confirms the existence of II terrace and three times new tectonic movements. Six TL ages were obtained, respectively belong to the Mid-Pleistocene(167.17 ± 14.21 ka), Late Pleistocene(113.27 ± 9.63ka, 42.22 ± 3.59 ka, 83.84 ± 7.13 ka, 75.47 ± 6.41 ka),Holocene(7.61 ± 0.65 ka). Combined with a special mud volcano - fault structure in Dasha River, it is concluded that in the Mid-Pleistocene, this area was controlled by NWW active faulting, and had experienced three stages with a strong differential uplifting and intensive erosion.