Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changes

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	Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changes
	Kaiser, Knut 1; Lai, Zhongping2 ; Schneider, Birgit 3; Schoch, Werner H.4; Shen, Xuhui 5; Miehe, Georg 1; Brueckner, Helmut 1
	2009-09-01
发表期刊	ISLAND ARC
卷号	18 期号:3 页码:404-427
关键词	Colluvial Eolian Fluvial Lacustrine Lhasa River
摘要	P>The Tibetan Plateau is highly sensitive to environmental changes and affects the settings of a far larger territory in Central Asia and beyond. Thus, knowledge on past environmental changes in that area is essential. Even though the Kyichu (Lhasa River) Valley and its tributaries is an easily accessible area, the Late Quaternary landscape evolution of southern Tibet is in general scarcely known. Therefore, 12 sedimentary sections in the middle and lower catchment were subjected to multidisciplinary analyses (sedimentology, paleopedology, AMS (14)C and luminescence dating, and charcoal determination) aiming at results on regional paleoenvironmental changes. At the altitude studied (3600-4000 m above sealevel), no glacial relics could be detected, indicating that the valley positions have been unglaciated since the Last Interglacial. The lack of fluvial-lacustrine structures above the floodplain is due to the aggradational character of this tectonically (sub-)active valley, which caused an alluvial burying of older valley bottoms. During the Late Pleistocene the mouth area of the Kyichu was occupied by a lake which was part of a larger dam-lake in the superordinate Yarlung Zhangbo Valley. On the valley flanks, loesses were predominantly deposited before the Last Glacial Maximum (LGM), whereas eolian sands were predominantly deposited around and after the LGM. Paleosols of Last Interglacial, Last Glacial and Holocene ages regularly occur at terrestrial sites representing temperate to cool and humid to semiarid conditions during soil formation. Ages of colluvial sediments indicate that the widespread barren valley slopes were primarily formed by Late Pleistocene erosion followed by a secondary Holocene erosion phase. Charcoal spectra indicate a Late Holocene change from a forest environment to a pastoral environment with sparse grasses, herbs and dwarf shrubs. It is assumed that the Late Holocene environmental changes, such as loss of forests/woodlands and erosion, have at least been reinforced by humans, enhancing a regional climatic aridification and cooling trend.
语种	英语
引用统计
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/5885
专题	青海盐湖研究所知识仓储盐湖地质与环境实验室
作者单位	1.Univ Marburg, Fac Geog, D-35032 Marburg, Germany 2.Chinese Acad Sci, Qinghai Inst Salt Lakes, Xining 810008, Peoples R China 3.Univ Leipzig, Dept Geog, D-04103 Leipzig, Germany 4.Lab Quaternary Woods, CH-8135 Langnau, Switzerland 5.China Earthquake Adm, Lab Earthquake Observat Space, Beijing 100036, Peoples R China
推荐引用方式 GB/T 7714	Kaiser, Knut,Lai, Zhongping,Schneider, Birgit,et al. Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changes[J]. ISLAND ARC,2009,18(3):404-427.
APA	Kaiser, Knut.,Lai, Zhongping.,Schneider, Birgit.,Schoch, Werner H..,Shen, Xuhui.,...&Brueckner, Helmut.(2009).Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changes.ISLAND ARC,18(3),404-427.
MLA	Kaiser, Knut,et al."Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changes".ISLAND ARC 18.3(2009):404-427.