Distribution and timing of Holocene and late Pleistocene glacier fluctuations in western Mongolia
Distribution and timing of Holocene and late Pleistocene glacier fluctuations in western Mongolia
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DOI：
10.3189/2016aog71a030
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发表时间：
2016-01
影响因子：
2.9
通讯作者：
F. Lehmkuhl;M. Klinge;H. Rother;Daniela Hülle
中科院分区：
文献类型：
--
作者：
F. Lehmkuhl;M. Klinge;H. Rother;Daniela Hülle
抽象。尽管是亚洲中北部古冰川学研究的关键地点，拥有最多的现代和更新世冰川，以及潮湿的俄罗斯阿尔泰和干燥的戈壁阿尔泰之间的过渡带，但对蒙古西部全新世和晚更新世冰川的精确程度和时间知之甚少。在这里，我们提出了详细的信息，现代和晚全新世冰川的分布，和新的成果解决地貌分化和数值测年（光释光，OSL）更新世冰川序列在这些地区。对于蒙古阿尔泰，年代学结果表明，大型冰的进步与海洋同位素阶段（MIS）4和2。这与来自蒙古中部的Khangai山脉的结果形成对比，该结果表明在MIS 3期间还发生了显着的冰进展。在更新世期间，俄罗斯和蒙古阿尔泰西部较潮湿的部分的冰川平衡线高度（ELA）低约500至> 1000米，而蒙古阿尔泰东部较干燥的地区为300-600米。更新世ELAs在Khangai山脉被压低了700-1000米，这表明在主要的冰川作用的时间比在蒙古阿尔泰东部更潮湿的条件。这种古ELA模式表明，冰期期间从干燥地区到潮湿地区的降水梯度比现在更加明显。
Abstract. Despite being a key location for paleoglaciological research in north-central Asia, with the largest number of modern and Pleistocene glaciers, and in the transition zone between the humid Russian Altai and dry Gobi Altai, little is known about the precise extent and timing of Holocene and late Pleistocene glaciations in western Mongolia. Here we present detailed information on the distribution of modern and late Holocene glaciers, and new results addressing the geomorphological differentiation and numerical dating (by optically stimulated luminescence, OSL) of Pleistocene glacial sequences in these areas. For the Mongolian Altai, geochronological results suggest large ice advances correlative to marine isotope stages (MIS) 4 and 2. This is in contrast to results from the Khangai mountains, central Mongolia, showing that significant ice advances additionally occurred during MIS3. During the Pleistocene, glacial equilibrium-line altitudes (ELAs) were ~500 to >1000m lower in the more humid portion of the Russian and western Mongolian Altai, compared to 300-600 m in the drier ranges of the eastern Mongolian Altai. Pleistocene ELAs in the Khangai mountains were depressed by 700-1000 m, suggesting more humid conditions at times of major glaciation than in the eastern Mongolian Altai. This paleo-ELA pattern reveals that the precipitation gradient from the drier to the more humid regions was more pronounced during glacial times than at present.