天山托木尔河流域第四纪冰川沉积序列及其初步年代学  

Sequences of the Quaternary Glacial Sediments and Their Preparatory Chronology in the Tomur River Valley,Tianshan Mountains

作　　者：赵井东[1] 王杰[2] 上官冬辉[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冰冻圈科学国家重点实验室,甘肃兰州730000 [2]兰州大学西部环境教育部重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2009年第4期628-633,共6页Journal of Glaciology and Geocryology

基　　金：中国科学院知识创新工程重要方向性项目(KZCX2-YW-301);国家自然科学基金项目(40501007;40601022);科技部科技基础性工作专项项目(2006FY110200)资助

摘　　要：托木尔河源于天山最大现代冰川作用中心托木尔峰西南坡的托木尔冰川,在第四纪冰期与间冰期的气候旋回中,遗留下了5套形态较为完整的冰川沉积.应用ESR测年技术对第一与第二级冰碛阶地(对应于第三套冰碛中地形较完整部分的冰碛,分布在托木尔河大桥与古库瓦河汇合口之间)以及第五套最高冰碛平台进行测年,依据初步的测试结果并结合地貌地层学原理可得出:5套冰碛分别形成于小冰期、新冰期、末次冰期、MIS6和MIS12,每次冰川作用过程中还包含着若干次级的冰川波动.根据现存的冰碛地形可推得:新冰期、末次冰期与MIS6时的冰川为山谷冰川,规模最盛时冰川长分别为47 km、60 km、≥70 km.The Tomur River originates on the southwestern slopes of the Tomur Peak,the largest modern glaciation centre in the whole Tianshan Mountains.Five sets of moraines are well-preserved in this valley during the Glacial-interglacial cycles in Quaternary,recording a complex history of Quaternary glacial landscape evolution.ESR dating technique was applied to determine the first and the second glacial terraces（The tills distribute from the Tomur Bridge to the confluence of the Guwar River and the Tomur River） and the oldest glaciated plateau of this valley.The ages of the first and the second glacial terraces and the glacial plateau are 18.720.1 ka BP,20.8 ka BP and 418.9 ka BP,respectively.Considering the principles of geomorphology and stratigraphy and these preliminary dating results,the following conclusions could be drawn： the tills deposited in Little Ice Age,Neoglaciation,Last Glaciation,MIS 6 and MIS 12,respectively.The glacial landforms indicate the ancient glacier was about 47 km,60 km,≥70 km in length at their maximum extent in Neoglaciation,Last glaciation and MIS 6.The age of the oldest glaciated plateau demonstrates that at least this segment of Tianshan Mountains began to develop glacier in MIS 12.

关 键 词：冰川地貌 冰期与间冰期旋回 海洋氧同位素阶段(MIS) 天山 

分 类 号：P534.63[天文地球—第四纪地质学]