DOI: 10.1016/j.quascirev.2013.09.016
Scopus记录号: 2-s2.0-84887148791
论文题名: Constraining holocene lake-level highstands on the tibetan plateau by 10Be exposure dating: A case study at tangra yumco, southern tibet
作者: Rades E.F. ; Hetzel R. ; Xu Q. ; Ding L.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2013
卷: 82 起始页码: 68
结束页码: 77
语种: 英语
英文关键词: Beach ridge
; Exposure dating
; Lake terrace
; Palaeo-climate
; Southern Tibet
; Tangra Yumco
Scopus关键词: Beach ridge
; Exposure dating
; Palaeo-climate
; Southern Tibet
; Tangra Yumco
; Beaches
; Lakes
; age determination
; bedrock
; dating method
; geochronology
; granite
; Holocene
; lake
; paleoclimate
; China
; Qinghai-Xizang Plateau
英文摘要: Many lakes on the Tibetan Plateau are surrounded by palaeo-shorelines that document former lake-level highstands and hence past changes in climate. Establishing accurate chronologies for these shorelines is crucial to correlate lake-level fluctuations with palaeo-environmental histories that are commonly inferred from lake sedimentary records. Here we apply surface exposure dating to constrain the age of two lake-level highstands at one of the largest Tibetan lakes - Tangra Yumco - which has well developed palaeo-shorelines located up to ~185m above the current lake. For sampling we focussed on wave-cut bedrock terraces that vary considerably in width, because they were carved into rocks of different erodibility. Samples from the highest strath terrace (~180-185m above the lake) at three different sites yield tightly clustered 10Be ages between 7.39±0.19 ka and 7.87±0.27 ka (internal errors), which constrain the end of an early Holocene lake-level highstand at 7.6±0.6 ka (external error). The consistency of the 10Be ages indicates that bedrock erosion by wave attack reduced the inherited 10Be component to negligible amounts, because otherwise samples would show considerable age scatter. Two bedrock samples from a lower terrace (~140-145m above the lake) and one amalgamated clast sample from a beach ridge on the same terrace yield 10Be ages between 4.04±0.14 ka and 4.50±0.15 ka. These ages document that the lake level dropped by ~40m between ~7.6 ka and ~4.3 ka. Granite boulders from the two investigated terraces yield apparent 10Be ages that are ~6 ka and ~27 ka older than the ages of the respective terraces, indicating that this sample type is not reliable in this setting. Overall, our results demonstrate that exposure dating of bedrock terraces provides a valuable tool to reconstruct lake-level histories on the Tibetan Plateau. © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60435
Appears in Collections: 过去全球变化的重建
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作者单位: Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Corrensstraße 24, 48149 Münster, Germany; Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Building No. 3, 16 Courtyard, Lincui Road, Chaoyang District, Beijing 100101, China
Recommended Citation:
Rades E.F.,Hetzel R.,Xu Q.,et al. Constraining holocene lake-level highstands on the tibetan plateau by 10Be exposure dating: A case study at tangra yumco, southern tibet[J]. Quaternary Science Reviews,2013-01-01,82