Uplift of Himalayas and its induced Global Environmental 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，以学术为目的，阐明喜马拉雅地区近3myr的隆升过程和印度季风的变化。对于钻取的岩心，我们进行了如下研究。古地磁研究：测量了自然剩余磁化强度和逐步交变磁场退磁强度，检测到与Mono Lake和Laschamp相对应的两次偏移。14C年龄测定：测定了12块碳化碎片的AMS - 14C年龄，明确了湖水的排水开始于11kyr B.P.3。3 .花粉分析：以10 cm为间隔，对最上层30 m的花粉组合进行了分析，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，检出了5属11种中央硅藻和22属38种Pennales硅藻，部分硅藻可作为湖泊古环境的指示物。古植物学研究：我们从160多个地层收集并鉴定了化石叶子，并检验了它们作为古气候指标的重要性。粒度分布：分析了最上层30 m的粒度分布，明确了湖相沉积与河流沉积的区别。粘土分析：采用XRD分解法对最上层50 m的粘土进行了分析，得到了近450 kyr的古气候变化曲线。无机化学分析：对最上层30 m粘土进行了放射性分析，考察了主要元素和稀土元素的变化与气候变化的关系。有机化学分析：以10 cm为间隔测量了最上层30 m的总有机碳量和碳氮比，并考察了它们的变化与环境和气候变化的关系。

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.