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Studies on the changes in Indian monsoon by drilling in the Paleo-Kathmandu Lake

古加德满都湖钻探研究印度季风变化

基本信息

批准号：
14340152
负责人：
SAKAI Harutaka
金额：
$ 9.41万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

We carried out core drilling of muddy lacustrine sediments at four sites in the southern part of the Kathmandu Valley. The total 800 m long cores were recovered and studied in order to reconstruct changes in paleoclimate and paleoenvironments in the valley during the last one million years. We reconstructed paleoclimatic curves of the last 700 kyr, on the bases of analyses of pollen, diatom, clay mineral, organic materiall and detrital grains, with 200 to 〜2000 years interval. Paleomagnetic and sedimentological studies on the drill cores and surface exposures revealed that le lake was born at about 1 Ma, caused by the uplift of the Mahabharat range to the south of Kathmandu. Surface geological survey in the southern part of the valley indicates that the lake-water drained two times at about 200 Ka and 12 Ka.δ 13C value of organic lacustrine mud shows at least seven times fluctuation ranging from -30 to -19 ‰. A fluctuation diagram of pollen assemblage shows similar pattern to that of δ 13C value, and indicative pollens of cold and dry climate increase when d13C has high value. It suggests that grasses including C4 plants expanded their distribution during the glacial period. Total organic carbon(TOC) and carbon/ nitrogen ration (T/N) shows inversed correlation with d 13C, and pollen concentration has good correlation with TOC and C/N. It implies that TOC and pollen concentration were controlled by land plants vegetated in the valley slope. When it was warm and wet climate, C3 land plants seem to have expanded their distribution. Pollen concentration, total valves of diatom and C/N ratio before ca. 350 ka show larger amplitude and larger value than those after 300 ka. During the middle Pleitocene from ca. 650 to 350 ka, frequency of diatom valves is characterized by monodominance of Cyclotella sp 1 and sp 2. These curious incidents are likely to be related to MIS stage 11 problem.

我们在加德满都河谷南部的四个地点进行了泥质湖相沉积物的岩心钻探。总共800米长的岩心被恢复和研究，以重建在过去的一百万年在山谷中的古气候和古环境的变化。根据孢粉、硅藻、粘土矿物、有机质和碎屑颗粒的分析，重建了距今70万年以来的古气候曲线，时间间隔为200 ~ 2000年。对钻孔岩芯和地表暴露的古地磁和沉积学研究表明，勒湖诞生于大约1 Ma，由加德满都以南的Mahabharat山脉的隆起造成。盆地南部的地表地质调查表明，湖水在200和12 Ka时有两次排泄，有机湖泥的δ 13 C值至少有7次波动，波动范围为-30 ~-19 ‰。花粉组合的波动图与δ 13 C值的波动图相似，当δ 13 C值高时，指示气候寒冷干燥的花粉增多。这表明，包括C4植物在内的禾本科植物在冰期扩大了分布。总有机碳（TOC）和碳氮比（T/N）与d13 C呈负相关，花粉浓度与TOC和碳氮比有较好的相关性。这表明，土壤总有机碳和花粉浓度受河谷植被的控制。当气候温暖湿润时，C3陆生植物的分布范围似乎有所扩大。花粉浓度、硅藻总瓣数和C/N比。350 ka后的振幅和值均大于300 ka后的振幅和值。在中更新世，从约。650 ~ 350 ka，硅藻瓣的出现频率以小环藻sp1和sp2的单优势为特征。这些奇怪的事件很可能与MIS第11阶段问题有关。

项目成果

期刊论文数量（90）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Tectono-metamorphic evolution of the far-Eastern Nepal Himalaya

尼泊尔喜马拉雅远东地区的构造变质演化

DOI：
发表时间：
2004
期刊：
Himalayan Journal of Sciences 2,4 (special issue)
影响因子：
0
作者：
Santa Man Rai;Harutaka Sakai;Bishal N.Upreti;Yutaka Takigami;Subesh Ghimire;Dibya R.Koirala;Tej P.Gautam;Desh R.Sonyak;Chandra P.Poudel
通讯作者：
Chandra P.Poudel

酒井治孝: "約100万年前に始まった琉球弧と西南日本弧の地殻変動"月刊地球. 24巻・11号. 813-819 (2002)

Harutaka Sakai：“大约 100 万年前开始的琉球弧和日本西南部弧的地壳变形”，《地球月刊》第 24 卷，第 11 期。813-819 (2002)。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

Uplift process of the Himalayan range and Tibetan plateau : with special references to the birth and change of monsoonal climatic system

喜马拉雅山脉和青藏高原的隆升过程：特别提到季风气候系统的产生和变化

DOI：
发表时间：
2005
期刊：
Jour Geol.Soc.Japan 111
影响因子：
0
作者：
Takeshita;H.;Harutaka Sakai
通讯作者：
Harutaka Sakai

Pleistocene rapid uplift of the Himalayan frontal ranges recorded in the Kathmandu and the Siwalik basin

加德满都和西瓦利克盆地记录的更新世喜马拉雅锋锋山脉快速隆升

DOI：
发表时间：
2005
期刊：
Palaeogeogr.Palaeoclimatol.Palaeoecol. 226
影响因子：
0
作者：
Harutaka Sakai;Hideo Sakai;Wataru Yahagi;Rie Fujii;Tatsuya Hayashi;Bishal Nath Upreti
通讯作者：
Bishal Nath Upreti

Middle to late Pleistocene climatic and depositional environmental changes recorded in the drilled core of lacustrine sediments in the Kathmandu Valley, central Nepal

尼泊尔中部加德满都谷地湖泊沉积物钻孔岩芯记录的中更新世中晚期气候和沉积环境变化