FORMATION OF THE HIMALAYAS AND GLOBAL ENVIRONMENTAL CHANGE-COOPERATIVE RESEARCH FOR ESTABLISHMENT OF THE RESEARCH INSTITUTE OF THE HIMALAYAS-

本研究的主要内容和成果概括如下：1.从喜马拉雅山隆升引起的环境变化看淡水软体动物的时空分布阐明了喜马拉雅地区新近纪晚期和第四纪淡水软体动物区系的变化。至于5Ma时以大量古北界成分向喜马拉雅山南部地区引入为特征的显著动物区系变化，则最有可能是由于喜马拉雅山隆升导致强烈季风系统的形成，从而使水鸟的迁徙变得活跃.西瓦利克群与喜马拉雅隆升有关的地质事件建立了西瓦利克群沉积时期古低速的估算方法。该方法明确地显示了各层位的古低速.博卡拉盆地的水环境调查了Phewa湖的水质和营养盐输入。由于地质条件的限制，大部分河水在入湖前就已沉入地下，控制着湖泊的水质.西瓦利克山区地质灾害对沿着乔科拉的滑坡进行了详细调查。一个有趣的倾倒结构与滑动表明，陡倾地层沿着的主要构造线，砂岩和泥岩之间的刚性对比，并迅速切割的河流是倾倒的主要原因。

Focuses and results of this research project are summarized as follows ;1. Time and space distribution of freshwater mollusca with reference to the environmental change caused by the Himalayan upliftThe faunal change of freshwater mollusca during the late Neogene and Quaternary in the Himalayan area was illuminated. As for the remarkable faunal change at 5Ma characterized by the introduction of many species of palaearctic elements to the southern area of the Himalayas, it is the most probable that the migration of water birds became active by the formation of intense monsoon system caused by the Himalayan uplift.2. Geological events in the Siwalik Group concerned with the Himalayan upliftThe method for estimation of the palaeoflow velocity during the sedimentation of the Siwalik Group was established. Based on the method, the palaeoflow velocity of each horizon was shown definitely.3. Water environment in Pokhara BasinThe water quality and the nutrient input in Phewa Lake was investigated. Because of the geological condition, the most of river water sink into the underground before reaching the lake, and it controls the water quality of the lake.4. Geological disaster in the Siwalik hillsThe detail investigation about the landslide along the Chor Khola was carried out. An interesting toppled structure with sliding indicates that steeply dipping strata along the major tectonic line, contrasting rigidity between sandstone and mudstone, and rapid dissection by a river were the major causes of the toppling.