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中国沙漠 ›› 2003, Vol. 23 ›› Issue (6): 703-708.

• 研究简报 • 上一篇    下一篇

普若岗日冰原西侧冰前风沙地貌的形成与我国冰川型沙漠的发现

李孝泽, 姚檀栋, 屈建军, 张伟民, 董光荣   

  1. 中国科学院 寒区旱区环境与工程研究所, 甘肃 兰州 730000
  • 收稿日期:2002-05-28 修回日期:2002-10-28 出版日期:2003-12-20 发布日期:2003-12-20
  • 作者简介:李孝泽(1964-),男(汉族),甘肃靖远县人,博士,研究员,主要从事沙漠演化研究。E-mail:leeyan@ns.lzb.ac.cn
  • 基金资助:
    国家自然科学基金(编号:40272079);中国科学院知识创新工程重大项目"西部生态环境演变规律与水土资源可持续利用研究"之专题"过去2000年来气候变化主要影响因素(编号:kzcx1-10-02)";国家重点基础研究规划"青藏高原形成演化及其环境资源效应"(G1998040802);中国科学院沙坡头沙漠研究与试验站开放基金(编号:200009)共同资助

The Formation of Proglacial Desert on the West of Icefield Puruogangri and Discovery of Glacial-Type Desert in China

LI Xiao-ze, YAO Tan-dong, QU Jian-jun, ZHANG Wei-min, DONG Guang-rong   

  1. Key Laboratory of Desert and Desertification, Cold and A rid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2002-05-28 Revised:2002-10-28 Online:2003-12-20 Published:2003-12-20

摘要: 在青藏高原中央、普若岗日冰原西侧流石坡地带山麓面上,分布有约100 km2的由戈壁与沙丘组成的地貌,这是世界罕见的、也是我国发现的首例中纬度、高海拔地区冰前沙漠沉积。野外地貌、地层测量和室内样品的粒度、矿物、14C测年分析等结果表明,其形成时代约为16 ka BP以来;沉积特征在沙丘沉积序列中表现为风成砂夹零星腐殖质层,在戈壁中表现为砾石表面具次生方解石或碳酸钙沉淀层;演化模式为冷直线式;形成条件为以下伏冰碛物为主要砂源,以行星西风环流和高原冬季风引起的地面西风为主要动力,以持续的寒冷半干旱为气候背景;成因主要与冰原西缘冰川作用形成丰富的冰碛物砂源有关;因此,这类沙漠与一般冰缘沙漠以河湖相砂为源具有显著区别,可称为"冰川型沙漠"。由于其形成兼与冰原、气候和环流的变化密切相关,所以它是高原腹地全新世气候环境变化的重要记录。

关键词: 普若岗日冰原, 冰前风沙地貌, 冰川型沙漠, 全新世环境

Abstract: There are about 100 km2 of aeolian landforms consisting of gobi and sand dunes on the piedmont surface of rock stream slope at west side of Puruogangri icefield in the center of the Qinghai-Tibet Plateau.This is one of the world s rare proglacial desert deposits and also the first example found in the mid-latitude and high-altitude region of China.Field observation,stratigraphic measurements,indoor sample analyses including particle size and minerals and 14C dating showed that they had been formed since 16 ka BP.Some of the most striking depositional features are that scattered humus layers are intercalated in the sand dune sedimentary sequence;on the surface of gobi gravel there are secondary calcite or CaCO3 precipitates.The desert exhibited a cold rectilinear evolutional pattern.It was formed with underling glacial tills as the main sand source,with the planet westerly circulation and west winds caused by the plateau s winter monsoon as the main driving forces,and with persistent cold and semiarid weather as the climatic background.In other words their origin is related to the abundant sand supply from glacial tills at the west side of the ice field.Such desert is quite different from the periglacial desert with fluviolacustrine deposits as sand source and therefore is called glacial-type desert.Since its origin is closely related to the changes of icefield,climate and atmospheric circulation,it provides important records of Holocene climate and environmental changes in the hinterland of the plateau.

Key words: Puruogangri ice field, proglacial aeolian sand landform, glacial-type desert, Holocene environment

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