Last 2000 years changes of climate, sea-level and eolian dusts detected by sedimentologic investigations of brackish lake sediments

水月湖近2000年来的矿物学特征是日本中部风沙浓度、海平面和降雨量变化的指示。水月湖的非冰川纹状沉积物表明，没有大量的陆源物质流入湖盆。ODP第127航次794和795站晚第四纪细粒沉积物中伊利石结晶度和石英/伊利石比值的顺序变化与Prell等人（1986）的氧同位素变化标准记录有很好的相关性。这表明，这些参数是有用的，以检测沉积物中的风尘浓度。也就是说，中国北方古土壤在湿润气候条件下大量形成。用铁矿物组成和伊利石/伊利石比值来反映海平面和降水的变化，研究表明，北方气候变化与海平面变化是平行的 ...更多信息 日本海南部若狭湾的水位变化在公元250，820，1170，1320，1500和1880年，当北方气候湿润时，若狭湾海平面上升。这是因为当时亚洲季风在全球温暖的气候中活动，活跃的季风将湿润的大气带入中国北方。在公元250、820、1050 - 1200、1320、1500和1880年，水月湖周围似乎下了大雨，若狭湾的海平面也在上升。这表明对马海流的流入，提供了潮湿的大气和海平面上升。公元350-550年和1350-1400年，若狭地区降水量大，但中国没有海平面上升，气候干燥凉爽，在此基础上，在中国和日本海沿着气候变暖之前，对马海峡附近的海平面上升，对马海流强烈流入日本海。这一事实表明，对马海峡海平面上升可能是东亚季风活动强度加快的触发因素。少

Mineralogical characteristics of last 2000 year records in meromictic lake, Lake Suigetsu, are the indicators of eolian dust concentrations, sea-level and rainfall changes in central Japan. Non-glacial varved sediment in Lake Suigetsu shows that there was no large influx of terrestrial materials into lake basin Sequential chages of illite crystallinity and quartz / illite ratio in late Quaternary fine-grained sediments at Site 794 and Site 795 of ODP Leg 127 of were well correlated to standard records of oxygen isotope change by Prell et al. (1986). This suggests that these parameters are useful to detect eolian dust concentration within sediments. In other words, occurrence of hydrated illite and small concentration of illite suggest that paleosol were greatly formed under wet climate in northern China. Sea-level and rainfall changes were detected by iron mineral composition and chlorite / illite ratio.Investigations show that climatic changes in northern China were parallel to sea-le … More vel changes of the Wakasa Bay in southern part of the Japan Sea. In 250,820,1170,1320,1500 and 1880 A.D., sea-level was risen in the Wakasa Bay when northern China was in wet climate. It is because that Asian monsoon was active in globally warm climate at these times, and that active monsoon took humid atmosphere into northern China. In 250,820,1050-1200,1320,1500 and 1880 A.D., there seems to have been heavy rainfall around Lake Suigetsu with sea-level rising in the Wakasa Bay. This suggests of influxing of Tsushima Current, supplying humid atmosphere and rising of sea-level. In 350-550 and 1350-1400 A.D., preciptations were heavy in the Wakasa region, though there are no rising of sea-level, and dry and cool climate in China.On the basis of mentioned above, there are sea-level rising around the Tsushima Strait and intense influx of the Tsushima Currents into the Sea of Japan before the beginning of warm climate in China and coastal area along the Sea of Japan. This fact sggests that sea-level rising in Tsushima Strait may be a trigger to accelerate intensity of monsoon activity in the East Asia. Less