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冰川冻土 ›› 2014, Vol. 36 ›› Issue (1): 63-70.doi: 10.7522/j.issn.1000-0240.2014.0008

• 冰冻圈与全球变化 • 上一篇    下一篇

东天山黑沟流域冰川沉积序列及OSL测年研究

殷秀峰1,2, 赵井东1, 伍云飞1,2   

  1. 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. 中国科学院大学 北京 100049
  • 收稿日期:2013-09-23 修回日期:2013-10-25 出版日期:2014-02-25 发布日期:2014-03-18
  • 通讯作者: 赵井东,E-mail:jdzhao@lzb.ac.cn E-mail:jdzhao@lzb.ac.cn
  • 作者简介:殷秀峰(1988-),男,江西九江人,2011年毕业于江西师范大学,现为硕士研究生,主要从事第四纪冰川与全球变化研究
  • 基金资助:

    国家自然科学基金项目(41371028;41230743;41071010);中国科学院知识创新工程重要方向性项目(KZCX2-EW-QN304);中国科学院西部之光项目;冰冻圈科学国家重点实验室自主课题(SKLCS-ZZ-20120003);中国科学院青藏高原研究所环境变化与地表过程重点实验室开放基金项目资助

OSL dating of glacial deposits and glaciations in the Heigou River valley, eastern Tianshan Range, China

YIN Xiufeng1,2, ZHAO Jingdong1, WU Yunfei1,2   

  1. 1. State Key Laboratory of Cryospheric Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2013-09-23 Revised:2013-10-25 Online:2014-02-25 Published:2014-03-18

摘要:

黑沟源于东天山最大现代冰川作用中心博格达峰的南坡. 在第四纪冰期与间冰期旋回中,该流域的冰川均发生过多次规模较大的进退,在谷中留下了较为完整的冰川沉积序列. 这些冰川地形包含有重要的古气候变化信息,对其研究可重建黑沟流域的冰川演化史. 应用OSL对该流域的冰川沉积物进行定年,测定结果表明冰水沉积物(沙质透镜体)比冰碛物更适宜应用单片再生剂量(SAR)测年技术进行测定. 基于测得的年龄并结合地貌地层学原理可初步得出:晚第四纪期间,黑沟流域共发生了5次规模较大的冰川作用,分别为全新世期间的小冰期(16世纪以来冷期的冰进)与新冰期(距今3~4 ka的冰进),末次冰期晚冰阶(MIS 2)与早冰阶(MIS 4)以及倒数第二次冰期(MIS 6).

关键词: OSL测年, 冰川地貌, 第四纪冰川, 天山

Abstract:

The Heigou River originates on the southern slope of the Mount Bogda, the largest glaciated center in the eastern Tianshan Range. Ancient glaciers advanced and retreated dramatically during the glacial-interglacial cycles in Quaternary, the spectacular glacial depositional landforms were produced and well-preserved in the Heigou River valley, recording a complex history of Quaternary glacial cycles and landform evolution. These glacial landforms are a direct imprint of fluctuation of the ancient glaciers. Dating the glacial landform could determine the temporal and spatial variations of the ancient glaciers in this valley and also provide essential information for reconstructing the paleoenvironment in this region. Optically stimulated luminescence (OSL) dating technique was used to determine the ages of the fluvioglacial deposits (the sand lenses that sandwiched between tills in moraines) and glacial tills in this valley with single aliquot regenerative-dose (SAR) protocol. Based on the dating results, and considered the principle of geomorphology and stratigraphy, the data of palaeoclimate as well as the glacial histories in the other valleys of the Tianshan Range, the following conclusion could be drawn: five glacial advances occurred in the Heigou River valley, they are glacial advances of Little Ice Age (glacial advances in the cold periods since the 16th century) and Neoglaciation (glacial advances during the last 3-4 ka) in Holocene, and other three glacial advances in the late and early period of last glaciation and penultimate glaciation, are equivalent in age to MIS 2, MIS 4 and MIS 6. In addition, the dating results of glacial tills and fluvioglacial deposits show that the SAR protocol was appropriate for equivalent dose (De) determination of fluvioglacial deposits and that OSL did not work to date glacial tills in this study, because the signals in quartz grains in glacial tills was not completely bleached. The glacial landforms indicate that the ancient glaciers at their maximum extensions during the LIA, Neoglaciation and the last glaciation were 7.6 km, 11 km and 14 km long, respectively.

Key words: OSL dating, glacial geomorphology, Quaternary glaciations, Tianshan Range

中图分类号: 

  • P534.63