基于年代学约束的白马雪山晚第四纪冰川作用  

GEOCHRONOLOGY CONSTRAINTED ON LATE QUATERNARY GLACIATION OF BAIMAXUE SHAN

作　　者：张威[1] 毕伟力[2] 刘蓓蓓[3] 刘啸[1] 张兵[4] 李超[4] 

机构地区：[1]辽宁师范大学城市与环境学院,大连116029 [2]中国科学院青藏高原研究所,北京100101 [3]北京大学城市与环境学院,北京100871 [4]昆明理工大学外国语言文化学院,昆明650500

出　　处：《第四纪研究》2015年第1期29-37,共9页Quaternary Sciences

基　　金：国家自然科学基金项目（批准号：41230743,41271093,40971010和40961001）资助

摘　　要：白马雪山（5429m）地处横断山脉腹地,海拔3800m以上保存着确切的第四纪冰川遗迹,对其进行深入研究,可以为重建西南季风影响区的环境演变历史以及区域冰期-间冰期系列对比提供依据.本文采用野外地貌调查与电子自旋共振测年（ESR）相结合的方法,查明白马雪山第四纪冰川发育的地貌特点,并对研究区的冰期系列进行划分.结果显示,白马雪山晚第四纪以来至少发生5次冰川作用,分别为中梁赣冰期（475±62ka,MIS 12）;倒数第二次冰期（MIS 6）,年代分别为166±22ka、142±17ka、209±23ka、153±15ka、120±16ka和180±20ka;末次冰期早期（MIS 4）,年代分别为57±6.8ka、67±8.7ka、81±11ka、77±11ka和64±7.7ka;末次盛冰期（19±2.5ka,LGM,MIS 2）以及全新世新冰期/小冰期（MIS 1）.研究区的冰川作用与青藏高原的脉动式抬升具有一定的对应关系.In the Baimaxue Shan （5429m）, the inner part of the Hengduan Mountains, typical glacial erosion and sedimentary landforms can be identified above the altitude of 3800m a.s.l., such as eirques, horns, aretes, U-shaped valleys, and lateral and terminal moraines. These glacial features indicate several glacial advances and a glaciated environment for Baimaxue Shan during the Late Quaternary. And these glacial landforms provide evidences not only for the evolution of the southwest monsoon but also for the correlation of different climate regions during the Quaternary glacial-interglacial cycles. The glacial sedimentary landforms mainly consistof moraines both in the glacial valley and in the piedmont. Five sets of moraines can be identified in the glacial valley A. The first set of moraines was formed above an altitude of 4450m a. s. 1. The second set of moraines was deposited between 4400m a.s.1, and 4230m a.s.1. The third set of moraines ranges from 4100m a.s.1, to 3920m a.s.1. The fourth set of moraines spans an elevation from 4090m a.s.1, to 3900m a.s.1. The fifth set of moraines was deposited near the valley-mouth, and stretched to an altitude of 3800m a.s.1, outside of the valley. Fourteen samples were taken for electron spin resonance （ESR） dating from the five sets of moraines. Five and six samples were taken from the third and fourth set of moraines, respectively. And one sample was taken from each of the other three moraines. According to the field investigation and ESR dating results, we ascertained the basic geomorphology features of the Quaternary glaciers and the glacial sequences in the study area. During the Late Quaternary, glaciers near the main peak of the Baimaxue Shan advanced at least five times. The five glacial advances can be assigned to the Zhonglianggan glaciation （MIS 12, MIS = Marine Oxygen Isotope Stage）（475± 62ka） and the Penultimate glaciation （MIS 6） during the Middle Pleistocene （166±22ka, 142±17ka, 209±23ka, 153±15ka, 120±16ka, and 180±20ka）, the ea

关 键 词：白马雪山 ESR测年 冰期系列 冰川地貌 

分 类 号：P534.63[天文地球—第四纪地质学] P512.4[天文地球—古生物学与地层学]