布尔津河支流喀纳斯河源于中俄蒙三国交界处友谊峰的南坡,为额尔齐斯河的重要源区.友谊峰连同奎屯峰等高峰形成了阿尔泰山最大的现代冰川作用中心.在第四纪期间,这些冰川都发生了规模较大的进退,在河谷中留下了形态较为清晰的冰川地形.应用OSL单片再生剂量测定技术对采自主U型谷两侧的高大侧碛垄进行了定年,测年结果分别为(27.2±2.0)ka(K-1)与(16.1±1.5)ka(K-2).基于地貌地层学原理、并结合已有的年代学资料(OSL与14 C)与古气候研究资料,末次冰期以来喀纳斯河流域共有5次规模较大的冰进,分别为小冰期、新冰期、末次冰期晚冰阶(MIS 2)、末次冰期中冰阶(MIS 3中期)与末次冰期早冰阶(MIS 4).
The Kanas River originates on the southern slopes of the Youyi Peak,the largest modern glaciation center in the Altay Mountains in China.Glaciers had advanced and retreated dramatically during the glacial-interglacial cycles in the Quaternary.Multiple moraine complexes were preserved in the headwaters of the Kanas River,recording a complex history of Quaternary glacial cycles and landscape evolution.In this study,two fluvioglacial deposits,which collected from the lateral moraines in the main U-shaped valley,were determined by optically stimulated luminescence(OSL) dating technique with single aliquot regenerative-dose(SAR).It is determined that the ages are 27.2±2.0 ka(K-1) and 16.1±1.5 ka(K-2).Based on the principles of geomorphology and stratigraphy,the previous dating results(by 14C,OSL) and the available palaeo-environmental data,five glacial advances have been confirmed in the Kanas River valley since the Last Glaciation.Three glacial advances have appeared during the last glacial cycle,corresponding to MIS 4,mid-MIS 3 and MIS 2.Two glacial advances occurred in the Holocene,which corresponded to Neoglaciation(the largest glacial advance in the last 3~4 ka in West China) and the Little Ice Age(glacial advance in the cold period since the 16th century).