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Uplift of Himalayas and its induced Global Environmental Changes

喜马拉雅山隆起及其引起的全球环境变化

基本信息

批准号：
11304030
负责人：
SAKAI Harutaka
金额：
$ 25.11万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

We carried out geological field investigation and core drilling for academic purpose in the southern part of the Kathmandu Basin, in order to clarify the uplift process of the Himalaya and changes in Indian monsoon during the last 3 myr. Regarding on the drilled cores, we undertook the following studies.1. Paleomagnetic study : we measured natural remanent magnetization and stepwise alternating field demagnetization, and detected two excursions corresponding to Mono Lake and Laschamp excursion.2. 14C age determination : we measured AMS C 14 ages of twelve pieces of carbonized fragment, and clarified that the draining of lake water started at 11 kyr B.P.3. Pollen analysis : we analyzed pollen assemblage of topmost 30 m at 10 cm interval, and obtained a curve of paleoclimatic changes during the last 50 kyr.4. Diatom analysis : we examined the existence and assemblage of fossil diatom, and detected 5 genus 11 species of Centrales and 22 genus and 38 species of Pennales, some of which are useful as indicators of paleoenvironments of the lake.5. Paleobotanical Study : we collected and identified fossil-leaves from more than 160 horizons and examined their significance as indicators of paleoclimate.6. Grain-size distribution : we analyzed grain-size distribution of topmost 30 m, and clarified the difference between lacustrine and fluvial sediments.7. Clay analysis : we carried out clay of topmost 50 m by XRD decomposition method, and obtained a curve of paleoclimatic change during the last 450 kyr.8. Inorganic chemical analysis : we carried out radioactivation analysis of clay of topmost 30 m, and examined the relationship between changes of major and rare-earth elements and climatic changes.9. Organic chemical analysis : we measured amount of total organic carbon and C/N ratio of topmost 30 m at 10 cm interval, and examined the relationship between their changes and environmental and climatic changes.

我们在加德满都盆地南部进行了地质野外调查和岩心钻探，以弄清喜马拉雅山脉的抬升过程和最近3年印度季风的变化。对于已钻取的岩心，我们开展了以下研究工作1.古地磁研究：测量了自然剩余磁化强度和阶梯交变退磁强度，发现了与莫诺湖和拉尚漂移对应的两次漂移。~(14)C年龄测定：测定了12块碳化碎片的~(14)C年龄，确定湖水排出始于11KYR B.P.3。孢粉分析：分析了距地面30米、间隔10厘米的孢粉组合，得到了近50年来的古气候变化曲线。硅藻分析：考察了化石硅藻的存在和组合，共检出5属11种中部硅藻和22属38种硅藻，其中一些化石硅藻对湖泊古环境有一定的指示意义。古植物学研究：我们收集和鉴定了160多个层位的树叶化石，并研究了它们作为古气候指标的意义。粒度分布：分析了最上层30m的粒度分布，明确了湖泊沉积与河流沉积的区别。粘土分析：用X射线衍射法对表层50m的粘土进行分解，得到了近450年来的古气候变化曲线。无机化学分析：对海拔30m以上的粘土进行放射性分析，探讨常量元素和稀土元素变化与气候变化的关系。有机化学分析：每隔10 cm测定30 m土层总有机碳含量和C/N比，并探讨其变化与环境和气候变化的关系。