The late Pleistocene glaciation in the Bogchigir Valleys (Pamir, Tajikistan) based on 10Be surface exposure dating
The late Pleistocene glaciation in the Bogchigir Valleys (Pamir, Tajikistan) based on 10Be surface exposure dating
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DOI：
10.1016/j.yqres.2012.09.002
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发表时间：
2012-09
影响因子：
2.3
通讯作者：
I. Röhringer;R. Zech;U. Abramowski;P. Sosin;A. Aldahan;P. Kubik;L. Zöller;W. Zech
中科院分区：
文献类型：
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作者：
I. Röhringer;R. Zech;U. Abramowski;P. Sosin;A. Aldahan;P. Kubik;L. Zöller;W. Zech
来自帕米尔高原的冰川年表不仅可以提供对过去温度变化的见解，还可以提供与北半球西风带和季风环流有关的过去降水变化的见解。我们提出了来自Bogchigir山谷的18个新的暴露年龄，以补充和完善我们之前在这些山谷的研究。该地区最广泛的冰期发生在~ 100 ka，在海洋氧同位素阶段（MIS） 5期间，这表明降水增加可能来自西风带和季风环流。随后的冰川推进发生在~ 80-75 ka，沉积了典型的“楚库尔”冰碛裂片。间接证据表明，~ 65 ka和40 ka的冰川推进，后者可能也记录了MIS 3期间季风水分供应的增加。在~ 28和24 ka， MIS 2的冰川推进幅度较小，反映了末次冰期的干旱化趋势。消冰作用开始于~ 21 ka，在~ 16和12 ka被小的静止或前进打断。局部定标点和冰川气候模拟将非常有助于减少系统方法学上的不确定性（仍然至少有10%），并得出更详细的古气候结论。
Glacial chronologies from the Pamir may not only provide insights into past changes in temperature, but also into past changes in precipitation related to the northern-hemispheric westerlies and the monsoonal circulation. We present 18 new exposure ages from the Bogchigir Valleys that complement and refine our previous studies in these valleys. The most extensive dated glaciation in the area occurred ~ 100 ka, during Marine Oxygen Isotope Stage (MIS) 5, and indicates increased precipitation likely from both the westerlies and the monsoonal circulation. A subsequent glacier advance, which deposited characteristic ‘chukur’ moraine lobes, occurred at ~ 80–75 ka. Circumstantial evidence points to glacial advances at ~ 65 and 40 ka, the latter likely also documenting increased monsoonal moisture supply during MIS 3. Less extensive glacial advances occurred during MIS 2 at ~ 28 and 24 ka and reflect the aridization trend during the course of the last glacial cycle. Deglaciation started ~ 21 ka, interrupted by minor stillstands or readvances at ~ 16 and 12 ka. Local calibration sites and glacier-climate modeling would be very helpful to reduce the systematic methodological uncertainties (still at least 10%) and to draw more detailed paleoclimatic conclusions.