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High resolution reconstruction of paleoclimate around the Japanese alpine area based on lake sediments analyses

基于湖泊沉积物分析的日本高山地区古气候高分辨率重建

基本信息

批准号：
15340168
负责人：
KUMON Fujio
金额：
$ 10.18万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340168/
关键词：
Paleoclimate Takano Formation total organic carbon glacial age Lake Nojiri pollen analysis marker tephra MIS 5 気候変動氷期間氷期 MIS 5 古環境有機炭素含有率 MIS3

项目摘要

The paleoclimate during the last 60,000 years have been reconstructed in detail, based on the drilled lake sediments from Lake Nojiri. Total organic carbon (TOC) and total nitrogen (TN) are used as new excellent proxies of paleoclimate as well as pollen analysis data. These data have about 50 years interval in average, and can provide one of standard climate changes around East Asia in the Last Glacial and Post-glacial periods.The drilled sediments of Takano Formation in Nagano City, 54.5 meters long, is composed of homogenous silty clay, and are intercalated with many tephra layers. Radiometric ages of several wide-spread marker tephras offers keys of age estimation of sediments. TOC and TN contents are measured in 1cm interval, about 26 years average. The vertical profile of TOC and TN contents varies concordantly with marine ^<18>O isotope curve and also with ^<18>O isotope curve of Greenland ice cores from 160,000 years to 40,000 years age. This result is the first detailed reconstruction of paleoclimate of Japanese land area.These reconstructions are one of best paleoclimate data in and around Japan in time resolution and long coverage. These data can be a standard of paleoclimate in Japan, because they can be correlated with other areas by the means of marker tephra.On the other hand, we have tried to clarify the process how TOC and TN contents in lake sediments reflect climate change. The modern relationship among TOC contents in sediment, biological productivity of lake water and weather factors in Lake Kizaki, central Japan were examined from 1982 to 2002. The study have revealed that winter temperature which means duration of cold season, control annual biological productivity in lake water, resulting in the amount of accumulated organic matters.

根据野尻湖钻探的湖泊沉积物，详细重建了过去 6 万年的古气候。总有机碳（TOC）和总氮（TN）被用作古气候和花粉分析数据的新的优秀代理。这些数据平均间隔约50年，可以提供东亚地区末次冰期和冰后期气候变化的标准之一。长野市高野组钻探沉积物长54.5米，由均质粉质粘土组成，夹有许多火山灰层。几种广泛分布的标记火山灰的辐射年龄为沉积物年龄估计提供了关键。 TOC和TN含量以1cm间隔测量，约26年平均值。 TOC和TN含量的垂直剖面与海洋^ 18 O同位素曲线以及格陵兰冰芯160,000年至40,000年的^ 18 O同位素曲线变化一致。该结果是日本陆地区域古气候的首次详细重建。这些重建是日本及其周边地区在时间分辨率和长覆盖范围方面最好的古气候数据之一。这些数据可以成为日本古气候的标准，因为它们可以通过标记火山灰与其他地区进行关联。另一方面，我们试图阐明湖泊沉积物中TOC和TN含量反映气候变化的过程。对1982年至2002年日本中部木崎湖沉积物中TOC含量、湖水生物生产力和天气因素之间的现代关系进行了研究。研究表明，冬季气温（即寒冷季节的持续时间）控制着湖水中的年生物生产力，从而导致有机物的积累量。