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

1.结合喜马拉雅抬升引起的环境变化，阐述了喜马拉雅地区新近纪晚期和第四纪淡水软体动物的区系变化。对于5 Ma以来以多种古北界成分引入喜马拉雅南部地区为特征的显著区系变化，最有可能的是喜马拉雅隆升导致的强烈季风系统的形成，使得水鸟的迁徙变得活跃。西瓦利克群中与喜马拉雅隆起有关的地质事件建立了斯瓦利克群沉积过程中古水流速度的估算方法。在此基础上，明确显示了各层位的古低速分布。博卡拉盆地的水环境调查分析了菲瓦湖的水质和营养物质的输入。由于地质条件的原因，大部分河水在入湖之前就下沉到地下，控制着湖泊的水质。Siwalik山区的地质灾害对Chor Khola沿线的滑坡进行了详细的调查。一个有趣的具有滑动的倾倒结构表明，沿主构造线陡峭的地层，砂岩和泥岩之间的刚性反差，以及河流的快速剥离是导致倾倒的主要原因。

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.