中文摘要：

堰塞是重要的极端地表过程之一,往往会造成灾难性的后果,对古堰塞湖的研究有助于对区域堰塞风险的认识。本文以青藏高原东缘大渡河上游石广东古滑坡堰塞湖为研究对象,地质证据显示该古堰塞湖的堵江高坝高约23 m,堵江滑坡的体积约1.6×10^7 m^3,堰塞湖的最小蓄水量为2.0×10^7 m^3。并选取两个湖相沉积剖面,采用单片再生法（single aliquot regeneration,SAR）与标准生长曲线法（standard growth curve,SGC）相结合的方法,测定了7个样品的光释光（optically stimulated luminescence,OSL）年龄,测年结果表明堰塞湖形成于距今约3.0 ka,结束于1.6 ka,即全新世晚期。初步推测堵江的古滑坡体可能由于地震诱发。

英文摘要：

Background, aim, and scope Dadu River is as one of the river in eastern fringe of the Tibetan Plateau. As it lies in the intersection of Xianshuihe, Anninghe and Longmenshan fault belt, thus the unique tectonic background and geomorphology have contributed to the formation of many landslide-dammed lakes. At present, the research on landslide dammed lake mainly reflects the two major aspects-mechanism of formation and disaster prevention and mitigation, and using the method of chronology is seldom discussed systematically. Damming is one of an important earth surface process, and always leads to disastrous results. The study of paleo-dammed lake contributes to the understanding of the regional risk of blocking river. In this paper, we study Shiguangdong（SGD） landslide dammed lake at the upstream of Dadu River in the eastern margin of the Tibetan Plateau. The sediment evidences show that the dam height is about 23 m, the volumes of landslide and minimum storage capacity are 16 million cubic metres and 20 million cubic metres. In recent years, more and more scholars have paid more attention to the relationship between the lake and the landscape. Materials and methods Two profiles were chosen and collected 7 optically stimulated luminescence（OSL） samples of which 4 samples from SGD1 profile and 3 samples from SGD2 profile, all the samples were kept from light in a dark place. First, the samples were processed chemically to remove carbonate and organic matter, then 38—63 μm quartz components were selected from the sample of purification, for the OSL dating experiment. The method of single aliquot regeneration（SAR） combined with standard growth curve（SGC） was adopted to study the optically stimulated luminescence dating of seven lacustrine samples, which were collected from these two profiles in Shiguangdong. Results The 7 effective OSL ages（1.8 ka, 10.6 ka, 2.6 ka, 3.0 ka, 2.0 ka, 1.6 ka, 1.7 ka, on the depth of 5.5 m, 6.7 m, 6.8 m, 7.7 m,0.9 m, 1.4 m, 4.6 m） results showed that the Shiguangdong