A high-resolution analysis of environmental changes during the last thousands years deduced from the cored sediments in Lake Kizaki, central Japan

根据日本中部木崎湖的岩心沉积物推断出过去数千年环境变化的高分辨率分析

• 批准号: 10640436
• 负责人: KUMON Fujio
• 金额: $ 2.3万
• 依托单位: Shinshu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640436/
• 关键词: Lake Kizaki; lacustrine deposit; climatic change; organic carbon; eolian dust; turbidite; flood sediment; Medieval Warm Period; メケレス型ピストンコアラー; 有機炭素量; 硫黄含有量; 風成塵量; 環境変遷

The surface cores of 2 to 3 m long were taken from the major basin floor at three sites of Lake Kizaki, using a new mechereth-type piston corer. Three ィイD114ィエD1C datings revealed that the cored sediments cover about 1500 to 1800 years before present. The sedimentation rate ranges from 1.3 to 1.9 mm/year (52 to 62 mg/cmィイD12ィエD1/year), and is lager than that estimated before this study. This high ratio is due to many turbidite layers which are estimated to be caused by large floods. The turbidite layers are characterized by the features such as relative high-density, low C and N contents and high C/N ratio. Major turbidite layers are enable to be correlated each other, suggesting large turbidity flows of basin scale. C/N ratio ranges from 10 to 13, suggesting that most organic materials are plankton of lake origin with minor amount of land plant materials. C and N contents fluctuate in short and long terms. The sort-term fluctuation is caused by turbidite dilution, and long-term fluctuation seems to be due to climatic changes. The warm period of the early Medieval Age and cool period of late Medieval Age (the Little ice Age) are identified in the proxy curve. Organic C and N contents of lake sediments are confirmed to be a good indicator of past climate.

使用新型机械活塞式取样器，从木崎湖三个地点的主要盆地底部采集了2至3米长的表层岩心。三次D114同位素D1C测年表明，取心沉积物覆盖了距今约1500至1800年。沉积速率范围为1.3至1.9毫米/年（52至62毫克/厘米水柱D12水柱D1/年），比本研究之前估计的要大。这一高比例是由于许多浊积岩层，估计是由大洪水造成的。浊积岩层具有相对高密度、低C、N含量和高C/N比等特征。各主要浊积岩层间可相互对比，显示出盆地规模的大型浊流。C/N比值在10 ~ 13之间，表明有机质主要为湖泊浮游生物，少量为陆生植物。C和N含量在短期和长期内波动。短期波动是由浊流稀释作用引起的，长期波动则可能是由气候变化引起的。在代用曲线中，中世纪早期的暖期和中世纪晚期的冷期（小冰期）被识别出来。湖泊沉积物中有机碳和氮的含量被证实是一个很好的指示过去的气候。

项目成果

Kumon, F.: "Saijo, Y. &Hayashi, H.(des.), Lake Kizaki, Blackwell Sci. Pty. Ltd."Paleolimonological Studies. 2000

Kumon, F.：“Saijo, Y.

Kumon, F.: "The records of earthquakes and floods in lake sediments - lacustrine turbidites -. Monthly Earth"vol. 22, no. 3. 156-161 (2000)

Kumon, F.：“湖泊沉积物中地震和洪水的记录 - 湖相浊积岩 -。地球月刊”卷。

多里英、公文富士夫、小林舞子、酒井潤一: "長野県北西部、青木湖の成因と周辺の最上部第四紀層"第四紀研究. 39. 1-13 (2000)

Ei Tari，Fujio Kumon，Maiko Kobayashi，Junichi Sakai：“长野县西北部青木湖的起源及其周围第四纪地层”第四纪研究39。1-13（2000）。

Kumon, F.: "Paleolimnological Studies."In Saijo, Y. & Hayashi, H.(eds.) Lake Kizaki, Blackwell Sci. Pty. Ltd.. (in press).

Kumon, F.：“古湖沼学研究”。载于 Saijo, Y.

公文 富士夫: "湖底堆積物中の地震や洪水の記録―湖成タービダイト―"月刊地球. 36,no.2. 156-161 (2000)

公文富士夫：“湖泊沉积物中的地震和洪水记录 - 湖相浊积岩”，地球月刊 36，第 2. 156-161 期（2000 年）。