Deglaciation and landscape history around Annapurna, Nepal, based on 10Be surface exposure dating
Deglaciation and landscape history around Annapurna, Nepal, based on 10Be surface exposure dating
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DOI：
10.1016/j.quascirev.2008.11.013
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发表时间：
2009-06
影响因子：
4
通讯作者：
R. Zech;M. Zech;P. Kubik;Krishna Kharki;W. Zech
中科院分区：
文献类型：
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作者：
R. Zech;M. Zech;P. Kubik;Krishna Kharki;W. Zech
高喜马拉雅山是构造、地貌和气候研究的关键地区，因为它的地形起伏很大，位于季风降水丰富地区和干旱/半干旱青藏高原之间的过渡地带。我们提出了10 Be表面暴露年龄22巨石从尼泊尔安纳普尔纳地区。年龄提高晚第四纪景观的历史和地貌过程中运作的喜马拉雅山的这一部分的理解。虽然我们的研究本质上是侦察，但它突出了灾难性事件的重要性，如山体滑坡和泥石流，对高山的剥蚀。例如，Dhampu-Gandaya滑坡（约4.1±0.6 ka）和Kali Gandaki山谷600 m冲积层（约2.1± 0.6 ka）的全新世暴露年龄表明了灾难性事件的频繁发生和程度及其对自然灾害的影响。我们还提供了一个解释晚第四纪冰川年代学在尼泊尔喜马拉雅山的研究地点紧密间隔的差异。喜马拉雅山的地形控制和空间可变的降水决定了冰川对温度和降水变化的敏感性。相应地，一些冰川与北方冰盖同步推进，而另一些冰川则在海洋同位素第3阶段和全新世早期季风降水增加时达到最大程度。
The High Himalaya is a key area for tectonic, geomorphological and climate studies, because of its extreme relief and location at the transition zone between areas with abundant monsoonal precipitation and the arid/semiarid Tibetan Plateau. We present10Be surface exposure ages on 22 boulders from the Annapurna area in Nepal. The ages improve understanding of the Late Quaternary landscape history and the geomorphological processes operating in this part of the Himalaya. Although our study is reconnaissance in nature, it highlights the importance of catastrophic events, such as landslides and debris flows, for denudation of high mountains. Holocene exposure ages for the Dhampu–Chooya landslide (∼4.1±0.6 ka) and for 600m of alluviation in Kali Gandaki Valley (∼2.1±0.6ka), for example, indicate the frequent occurrence and extent of catastrophic events and their implications for natural hazards. We also offer an explanation for the differences in Late Quaternary glacial chronologies at closely spaced study sites in the Nepal Himalaya. Topographically controlled and spatially variable precipitation in the Himalaya determines the sensitivity of glaciers to changes in temperature and precipitation. Accordingly, some glaciers advanced in-phase with Northern Hemisphere ice sheets, whereas others reached their maximum extent at times of increased monsoonal precipitation during Marine Isotope Stage 3 and the early Holocene.