西昆仑山北缘下更新统西域组中上部泥石流沉积的发现及其意义

The discovery of debris flow sediments in the middle-upper Xiyu Formation of Lower Pleistocene on the northern margin of West Kunlun Mountains and its significance

报道了在西昆仑山北缘的恰哈、桑株、柯克亚等地的西域组中上部地层中发现数十层泥石流沉积。容重测量表明,泥石流以粘性泥石流为主,典型沉积相组合为AC、AA1C、DAA1BC、AA1BC、AA1B、A1BC,反映泥石流沉积从上游向下游由扇顶向扇缘环境演化,泥石流沉积时代对比为早更新世早中期。青藏高原西北缘西域组中上部泥石流沉积的发现,为分析该区西域组沉积时期的构造背景、地貌条件、气候特征提供了重要的新资料,为研究青藏高原隆升及其引发的地质灾害效应提供了新的证据,对泥石流地质灾害的防治提出了预警。

Dozens of layers of debris flow were discovered in Qiaha,Sangzhu and Kekeya areas on the northern margin of West Kunlun Mountains.Density measurements show that they are mainly clayey debris flows.Typical combinations of sedimentary facies are AC,AA1C,DAA1BC,AA1BC,AA1B and A1BC,suggesting that the sedimentary facies of debris flow evolved from top to edge of the alluvial fan,and the age of debris flow sediments is early-middle Early Pleistocene through comparison.The discovery of debris flow sedimentation in middle-upper Xiyu Formation on the northern margin of Tibetan Plateau provides important new information on tectonic background,geomorphic conditions and climate characteristics for analyzing sedimentation age of Xiyu Formation in the north margin of West Kunlun Mountains and also supplies new evidence for the uplift of Tibetan Plateau ant its geological disaster effects,thus putting forward warning for the prevention and treatment of debris flow disaster.