Event layers in the Japanese Lake Suigetsu 鈥楽G06鈥?sediment core: description, interpretation and climatic implications
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- 作者：Gordon Schlolaut ; Achim Brauer ; Michael H. Marshall ; Takeshi Nakagawa ; Richard A. Staff ; Christopher Bronk Ramsey ; Henry F. Lamb ; Charlotte L. Bryant ; Rudolf Naumann ; Peter Dulski ; Fiona Brock ; Yusuke Yokoyama ; Ryuji Tada ; Tsuyoshi Haraguchi ; Suigetsu 2006 project members
- 关键词：Floods ; Earthquakes ; Microfacies ; Microscopy ; 渭XRF ; East Asia ; Lacustrine ; Typhoons ; LGM
- 刊名：Quaternary Science Reviews
- 出版年：1 January, 2014
- 年：2014
- 卷：83
- 期：Complete
- 页码：157-170
- 全文大小：6503 K
文摘
Event layers in lake sediments are indicators of past extreme events, mostly the results of floods or earthquakes. Detailed characterisation of the layers allows the discrimination of the sedimentation processes involved, such as surface runoff, landslides or subaqueous slope failures. These processes can then be interpreted in terms of their triggering mechanisms. Here we present a 40聽ka event layer chronology from Lake Suigetsu, Japan. The event layers were characterised using a multi-proxy approach, employing light microscopy and 渭XRF for microfacies analysis. The vast majority of event layers in Lake Suigetsu was produced by flood events (362 out of 369), allowing the construction of the first long-term, quantitative (with respect to recurrence) and well dated flood chronology from the region. The flood layer frequency shows a high variability over the last 40聽ka, and it appears that extreme precipitation events were decoupled from the average long-term precipitation. For instance, the flood layer frequency is highest in the Glacial at around 25聽ka BP, at which time Japan was experiencing a generally cold and dry climate. Other cold episodes, such as Heinrich Event 1 or the Late Glacial stadial, show a low flood layer frequency. Both observations together exclude a simple, straightforward relationship with average precipitation and temperature. We argue that, especially during Glacial times, changes in typhoon genesis/typhoon tracks are the most likely control on the flood layer frequency, rather than changes in the monsoon front or snow melts. Spectral analysis of the flood chronology revealed periodic variations on centennial and millennial time scales, with 220聽yr, 450聽yr and a 2000聽yr cyclicity most pronounced. However, the flood layer frequency appears to have not only been influenced by climate changes, but also by changes in erosion rates due to, for instance, earthquakes.