Abstract:
Located in the southeastern part of the Qinghai-Tibet Plateau, the Milin region is characterized by strong internal and external dynamics, leading to frequent geological disasters. In this area, glacial lake debris flow deposits are widely distributed, with large areas, significant depth, and complex sedimentary relationships. Understanding the stages of glacial lake debris flow and their relationship with tectonic activities in the Milin region is crucial for reconstructing the regional geological environment and studying the genesis of debris flows. This knowledge is also essential for predicting future debris flow events in the region. Through field investigations, satellite imagery interpretation, UAV aerial photography, and laboratory tests, this study identified the accumulation characteristics of glacial lake debris flows in the Milin area, studied the development timeline of these flows, and revealed the relationship between debris flows and tectonic activity, along with their influencing factors. The main findings are as follows: (1)The longitudinal slope of the glacial lake debris flow accumulation area in the Milin region is small, and the area exhibits three distinct plane forms: fan-shaped, fish-tail shaped, and stacked. (2)The glacial lake debris flows in the study area can be divided into three periods: 62.2-74 ka, 37.3-44.9 ka, and 16.1-23.6 ka. Debris flows closer to the lower reaches of the Yarlung Zangbo River tend to have an earlier formation age. (3)The factors affecting the time coincidence rate include the distance between the fault zone and the debris flow gully, the scale of the fault, and the nature of the fault. The time coincidence rate is negatively correlated with the distance between the fault zone and the debris flow gully, and positively correlated with the scale of the fault.