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塔合曼滑坡体是发育在新疆帕米尔高原东部1895年塔什库尔干7级地震区北端的一个大型滑坡体,总体呈“舌”形,由崩塌区、滑坡区和堆积区三部分组成,在滑坡区和堆积区分别形成了平行与垂直于滑坡体滑动方向的滑坡体台阶。本文介绍了该滑坡体的基本特征并采用宇宙成因核素测年技术对其形成年代进行了测定,简要论述了该测年技术的基本原理、野外采样原则及样品前处理过程。采自滑坡体不同部位的6个片麻岩巨砾样品的~(10)Be暴露年龄结果非常一致,表明该滑坡体发生在6.8±0.2ka,同时也表明了~(10)Be暴露测年是研究大型滑坡的有效测年手段。结合该滑坡体被慕士塔格断层断错并形成断层陡坎、滑坡体内发育的冲沟规模以及巨砾表面较厚的岩石漆,我们认为该滑坡体并非1895年地震的产物。
The Tarhaman landslide body is a large-scale landslide body developed at the northern end of the Tashkur MS 7 MS 1895 east of the Pamirs in Xinjiang. It is generally “tongue-like” in shape and consists of three parts: the collapsed area, the landslide area and the accumulation area. The landslide area and the accumulation area respectively form the landslide steps parallel and perpendicular to the sliding direction of the landslide body. This paper introduces the basic characteristics of the landslide body and uses the cosmic dating technique to measure the age of the landslide body. The basic principle of the dating technique, the principle of field sampling and the sample pretreatment process are briefly discussed. The results of ~ (10) Be exposure ages of 6 gneiss boulders collected from different parts of the landslide show very consistent results, indicating that the landslide body occurred at 6.8 ± 0.2 ka and also showed ~ 10 Be dating exposure It is an effective dating method for studying large landslides. Combined with the fact that the landslide body was broken by the Muztagata fault and formed a fault scarp, the gully scale developed in the landslide and the thick lacquer on the surface of the boulder, we think this landslide body is not the product of the 1895 earthquake.