川藏交通廊道冷曲河段巨型滑坡复活期次与成因机制研究

Investigating the age, the recurrence interval of giant fossil landslides is extremely useful for determining conditions that lead to the landslides, as well as estimating the hazards of future events and understanding Quaternary geologic history in high mountains areas. Nevertheless, determining the age of giant landslide events is always related to certain uncertainties, independent of the dating approach being used. The Basu section of Nu River and the Lengqu River section of the Sichuan-Tibet Highway within the Sichuan-Tibet traffic corridor exhibits extreme landslide activity and large-scale landslide and super large-scale landslide are widely distributed in this area. Consequently, the landslides have become a major concern for the proposed construction of the Sichuan Tibet railway and expressway. This study proposes, firstly, to analyze the age of the landslide by a combination of different dating methods. Terrestrial Cosmogenic Nuclides (TCN) will be utilized to focus on primary landslide features, e.g. the main scarp, sliding surface and slide shoulders. Features related to the occurrence of the landslides, e.g. landslide ponds, will be analyzed by means of Optically Stimulated Luminescence (OSL), Electron spin resonance (ESR) and Radiocarbon (14C) dating. This will be supported by relative dating methods of rock weathering based on the Geomorphology, Stratigraphy and Engineering Geology. Secondly, the project aims to establish a reliable age, occurrence probabilities and future evolution processes of giant landslide events by independent absolute and relative dating of landslide deposits and pond deposits considering the analysis of landslide causes and processes. Thirdly, according to the evolution processes and the formation mechanisms of the typical giant landslides, the formation mechanism and triggering mechanism of the huge ancient landslides in the traffic corridor of Sichuan and Tibet are summarized. The study is of a high methodical value because it provides the most reliable time, developments and recurrence constraints of individual landslides.Thereby, the research of giant landslide in the traffic corridor of Sichuan and Tibet, natural disaster prevention and control and large project construction will greatly benefit from the methodical approaches put forward by the project, and shall serve the national policy of "the Belt and Road".

巨型滑坡每次活动准确的年代对于揭示一个地区滑坡在时间上的活动规律，进而评价该地区的滑坡灾害风险至关重要。由于各种测年技术各自的局限性以及采样部位差异，往往对同一滑坡得出不同的测年结果。川藏交通廊道怒江八宿段及支流冷曲河段巨型滑坡集中分布、且多期多阶段活动，已成为拟建的川藏铁路和高速公路建设的关键控制性节点之一。本项目拟利用地貌学、沉积学、工程地质学确定巨型滑坡的相对年代，研究TCN、OSL、ESR、14C等多种测年方法和在滑坡不同取样部位获得的多种介质的测年机制；通过研究滑坡的成因与过程、相对年代、绝对年代，以及结合地层层序分析的交叉验证，研究古滑坡测年机制并提出综合测年方案；确定研究区域巨型滑坡发生时间与复活期次和重建滑坡演化过程；并推演区域性巨型滑坡形成机理和触发机制。为川藏交通廊道内巨型滑坡灾害风险评价、自然灾害防治、大型工程建设等科学问题研究提供范例，服务“一带一路”国家战略。

巨型滑坡每次活动准确的年代对于揭示一个地区滑坡在时间上的活动规律，进而评价该地区的滑坡灾害风险至关重要。由于各种测年技术各自的局限性以及采样部位差异，往往对同一滑坡得出不同的测年结果。川藏交通廊道怒江八宿段及支流冷曲河段巨型滑坡集中分布、且多期多阶段活动，已成为拟建的川藏铁路和高速公路建设的关键控制性节点之一。本项目在冷曲河段开展了古滑坡识别编目和过剩地形对古滑坡潜在风险位置的指示作用研究、古滑坡和古滑坡二次复活滑坡易发性评价对比研究的基础上，利用地貌学、沉积学、工程地质学确定巨型滑坡的相对年代，研究TCN、OSL、ESR、14C等多种测年方法和在滑坡不同取样部位获得的多种介质的测年机制；探讨了TCN古滑坡测年方法应用进展和测年限制因素、OSL古滑坡测年方法应用进展和堰塞湖的湖相沉积物OSL测年中的饱和含水量研究、古滑坡定年精度的提高途径；进行了德恒隆滑坡、乱石包滑坡、苏哇龙滑坡TCN测定、以及青藏高原东南缘冷曲流域旺北村滑坡、旺北东1号滑坡、旺北东2号滑坡、八宿滑坡等典型古滑坡的TCN测定，和冷曲河段沙木村古堰塞湖湖相沉积、八宿滑坡堰塞湖湖相沉积以及林卡滑坡堰塞湖湖相沉积OSL测定，进行灾变过程剖析研究。通过研究滑坡的成因与过程、相对年代、绝对年代，以及结合地层层序分析的交叉验证，研究古滑坡测年机制并提出综合测年方案；确定研究区域巨型滑坡发生时间与复活期次和重建滑坡演化过程；并推演区域性巨型滑坡形成机理和触发机制。为川藏交通廊道内巨型滑坡灾害风险评价、自然灾害防治、大型工程建设等科学问题研究提供范例，服务“一带一路”国家战略。