Holocene proglacial loess in the Ranwu valley, southeastern Tibet, and its paleoclimatic implications
Holocene proglacial loess in the Ranwu valley, southeastern Tibet, and its paleoclimatic implications
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藏东南然乌河谷全新世冰期黄土及其古气候意义
DOI：
10.1016/j.quaint.2014.04.016
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发表时间：
2015-06
影响因子：
2.2
通讯作者：
Zhu, Liping
中科院分区：
文献类型：
--
作者：
Yang, Yibo;Lin, Yongchong;Jiang, Tao;Zhu, Liping
青藏高原广泛分布着冰川和风成沉积物。尽管冰川作用在北方许多冰川地区的黄土形成中起着重要作用，但青藏高原的冰前黄土却鲜有报道，其起源、物质来源和古气候意义至今仍不清楚。我们在西藏东南部然乌河谷发现了小面积的冰前黄土沉积。粒度、地球化学和地貌证据以及当地沙尘暴的观测表明，来古冰川（长约30 km）的冰水沉积物是当地黄土的主要来源。我们还发现，来自该冰川的冰川风是主要的搬运媒介，从而推测然乌黄土的形成时间约为2000年。6.6 ka，与新冰期早期来古冰川的推进有关，在封闭和深切割的冰川谷中产生了冰川风和局部沙尘暴。这是由两个冰芯的基础放射性碳年龄和青藏高原全新世冰川冰帽的合成支持。黄土层和古气候指标表明，在约2000年有两个干旱阶段。6.6-6 ka和ca. 2.9 ka到现在，对应于印度夏季季风的两个有据可查的减弱阶段。这项研究强调，虽然当地的风成沉积物总是覆盖一个小的区域，他们也有可能记录一些线索的区域气候变化在一些高山地区。其形成机制和古气候意义有待进一步研究。
Glaciers and aeolian sediments are widespread on the Tibetan Plateau. Although glaciations have played an important role in the formation of loess in many glaciated regions in the Northern Hemisphere, proglacial loess on the Tibetan Plateau is rarely reported, and its origin, source, and paleoclimatic implications remain unclear. We have found a small area of proglacial loess deposits in the Ranwu valley, southeastern Tibet. Grain-size, geochemical and geomorphologic evidence, as well as observations of local dust storms, reveal that the outwash sediments of the Laigu glacier (∼30 km long) are the primary source for the local loess. We also found that the glacial wind from this glacier is the main transport vector, and thus speculate that the onset of the Ranwu loess, at ca. 6.6 ka, correlates with the early Neoglacial advance of the Laigu glacier, which generated glacial winds and local dust storms in the closed and deep-incised glacial valley. This is supported by the basal radiocarbon ages of two ice cores and a synthesis of Holocene glacial stadials on the Tibetan Plateau. Loess layers and paleoclimatic proxies indicate two drought stages at ca. 6.6–6 ka and ca. 2.9 ka to the present, corresponding to two well-documented weakened stages of the Indian Summer Monsoon. This study highlights that, although local aeolian sediments always cover a small area, they also have potential to record some clues of regional climate changes in some alpine regions. Much more detailed studies should be done to reveal their specific formation mechanisms and paleoclimatic implications.
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影响因子：
64.8
作者：
L. Zhou;F. Oldfield;A. Wintle;S. Robinson;J. T. Wang
通讯作者：
L. Zhou;F. Oldfield;A. Wintle;S. Robinson;J. T. Wang
影响因子：
2
作者：
Jia-Fu Zhang;Liping Zhou
通讯作者：
Jia-Fu Zhang;Liping Zhou
影响因子：
4
作者：
Y. Küster;R. Hetzel;M. Krbetschek;Mingxin Tao
通讯作者：
Y. Küster;R. Hetzel;M. Krbetschek;Mingxin Tao
2006年4月16日至17日北京大尘暴：地球化学性质及沙源指示
影响因子：
0.8
作者：
Ju, Jian-Ting;Zhang, Wen;Feng, Jin-Liang;Zhen, Xlao-Lin;Zhou, Li-Ping;Gao, Shao-Peng;Zhu, Ll-Ping
通讯作者：
Zhu, Ll-Ping
影响因子：
2.3
作者：
Jimin Sun
通讯作者：
Jimin Sun