祁连山东段金塔河流域层状地貌时代与成因探讨  

Age and Genesis of the Stepped Geomorphic Surfaces in Jinta River Basin of the Eastern Qilian Mountains

作　　者：高红山[1] 潘保田[1] 李吉均[1] 邬光剑[2] 李炳元[3] 业渝光[4] 

机构地区：[1]兰州大学西部环境教育部重点实验室和地理科学系,甘肃兰州73000 [2]中国科学院青藏高原研究所,北京100085 [3]中国科学院地理科学与资源研究所,北京100101 [4]国土资源部青岛海洋地质研究所,山东青岛266071

出　　处：《山地学报》2005年第2期129-135,共7页Mountain Research

基　　金：国家自然科学基金项目 (4 0 1710 10 ) ;教育部博士点基金项目 (2 0 0 3 0 73 0 0 17);教育部青年教师奖励基金联合资助~~

摘　　要：祁连山东段金塔河流域分布着两级夷平面(山顶面与主夷平面)、一级剥蚀面和多级河流阶地,它们是晚新生代青藏高原阶段性隆升的产物。通过电子自旋共振(Electronspinresonance ,简写为ESR)、热释光(Lumines cence ,简写为TL)、红外释光(Infra redstimulatedluminescence ,简写为IRSL)和14 C等绝对测年手段并结合区域对比的研究表明,该区山顶面形成于老第三纪,主夷平面形成于中新世至上新世,剥蚀面解体于1 4MaB P 左右。其后金塔河流域发育5～6级阶地,形成时代大致为1 2 4MaB P 、0 78MaB P 、0 14MaB P 、0 0 6MaB P 、0 0 3MaB P 和0 0 1MaB P 。结合河流阶地的形成年代、发育特征以及邻区阶地的发育模式研究表明。In the Jinta River basin, two planation surfaces and one erosion surface are developed, which are Summit Surface, Main Surface and Erosion Surface. The Summit Surface have formed in Oligocene and early Miocene, and the Main Surface between 20～3.6 Ma B.P., according to the Qinghai-Xizang Plateau research. The ESR chronology on gravel beds, show that the erosion surfaces dismantled around 1.4 Ma B.P.. Therefore, a dramatic uplift event was foreseen in east Qilian Shan at around 1.4 Ma B.P.. However, dismantling of the erosion surface in the Yellow River watershed west to Liupan Shan occurred around 1.8 Ma B.P.. The discrepancy in timing the dismantling of the erosion surface may reflect, to some extent, regional differential uplifts of the Tibetan Plateau during the late Cenozoic. With subsequent uplifting of the Tibetan Plateau, episodic river down-cutting, stream captures and headwater erosions can be seen widely throughout this region, created several alluvial terraces in the Jinta River valley. According to the ESR (Electron spin resonance),TL (Luminescence),IRSL (Infra-red stimulated luminescence) and ()^(14)C dating methods, the ages of 6 terrace is 1.24 Ma B.P., 0.87 Ma B.P., 0.78 Ma B.P., 0.42 Ma B.P., 0.25 Ma B.P., 0.14 Ma B.P. and 0.01 Ma B.P. respectively. After analyses on the ages of gravel bed accumulations and the ages of channel down-cuttings, we find that climate variations play significant roles in controlling regional geomorphic evolutions even within the tectonic active regions.

关 键 词：形成时代 剥蚀面 河流阶地 金塔河 祁连山东段 

分 类 号：P931.2[天文地球—自然地理学]