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文章以青藏高原东缘龙门山活动构造的地貌标志为切入点,在汶川-茂汶断裂、北川断裂、彭灌断裂和大邑断裂等主干活动断裂的关键部位,对断错山脊、洪积扇、河流阶地、边坡脊、断层陡坎、河道错断、冲沟侧缘壁位错、拉分盆地、断层偏转、砾石定向带、坡中槽、弃沟和断塞塘等活动构造地貌和断裂带开展了详细的野外地质填图和地貌测量,利用精确的地貌测量数据和测年数据,定量计算了龙门山主干断裂的逆冲速率和走滑速率,结果表明在晚新生代时期龙门山构造带仅具有微弱的构造缩短作用,其中逆冲速率的速度值小于1.1mm/a,走滑速率的速度值小于1.46mm/a,表明走滑分量与逆冲分量的比率介于6∶1~1.3∶1之间,以右行走滑作用为主。在此基础上,对各主干活动断裂的逆冲速率和走滑速率进行了定量的对比研究,结果表明自北西向南东4条主干断裂的最大逆冲分量滑动速率具有变小的趋势,而走滑分量的滑动速率则具有逐渐变大的趋势,显示了从龙门山的后山带至前山带主干断裂的走滑作用越来越强。由此推测现今的龙门山及其前缘盆地不完全是由于构造缩短作用形成的,而主要是走滑作用和剥蚀卸载作用的产物。另外,根据沉积、构造、盆地充填体的几何形态、地貌、古地磁等标定和对比了龙门山在中生代和新生代的走滑方向,表明龙门山构造带在中生代与新生代之交走滑方向发生了反转,即由中生代时期的左行变为新生代时期的右行。
Based on the geomorphological landmarks of the Longmenshan activity in the eastern margin of the Qinghai-Tibet Plateau, the paper analyzes the faults at the key sites of faults such as the Wenchuan-Mauwen Fault, the Beichuan Fault, the Peng-Guan Fault and the Dayi Fault. , River terraces, slope ridges, fault scarps, faulty channels, gully lateral wall dislocations, pull-apart basins, fault deflections, gravelly directional belts, sloping basins, abandoned ditches and fault blocks. The detailed geological mapping and geomorphological measurements of the fault zone were carried out. The accurate geomorphologic data and dating data were used to quantitatively calculate the thrust rate and the strike slip rate of the Longmenshan main fault. The results show that during the Late Cenozoic period, The tectonic belts have only weak tectonic shortening, of which the velocity of thrust is less than 1.1mm / a and the velocity of slip is less than 1.46mm / a, indicating that the ratio of slip to thrust is between 6: 1 ~ 1.3: 1, with the main right-hand skidding. On the basis of this, a quantitative comparative study on the thrusting rate and the strike slip rate of each active fault has been carried out. The results show that the maximum thrust component slip rate decreases from northwest to south east, The slip rate of the strike-slip component tends to become larger and larger, indicating a more and more slippery strike from the back mountain of Longmenshan to the main fault of the former mountain. It is speculated that today’s Longmenshan and its frontal basins are not completely formed by tectonic shortening, but are mainly the result of strike-slip and denudation unloading. In addition, the strike-slip directions of the Longmenshan during the Mesozoic and Cenozoic periods are calibrated and compared according to the sedimentary, tectonic and basin geometry, geomorphology and paleomagnetism, indicating that the Longmen Shan tectonic belt was in the strike-slip direction during Mesozoic and Cenozoic The reversal occurred from the left bank of the Mesozoic era to the right bank of the Cenozoic.