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

近2000年来的矿物学特征反映了日本中部风尘浓度、海平面和降雨量的变化。绥格苏湖非冰期变异沉积物表明，没有陆源物质大量进入湖盆，晚第四纪细粒沉积物中的伊利石结晶度和石英/伊利石比值的序列变化与Prell等人的氧同位素标准记录有很好的相关性。(1986年)。这表明这些参数对探测沉积物中的风尘浓度是有用的。也就是说，水化伊利石的出现和少量的伊利石表明，中国北部古土壤是在湿润气候下大量形成的。用铁矿物组成和绿泥石/伊利石比值反映了海平面和降雨量的变化。研究表明，中国北部的气候变化与海…平行日本海南部的和歌沙湾有更多的变化。公元250、820、1170、1320、1500年和1880年，和卡萨湾海平面上升，中国北部处于湿润气候。这是因为此时的亚洲季风活跃在全球温暖的气候中，活跃的季风将湿润的大气带到了中国北部。在公元250、820、1050-1200、1320、1500和1880年，绥格苏湖周围似乎出现了强降雨，和卡萨湾的海平面上升。这意味着对马洋流的涌入，提供了湿润的大气和海平面的上升。公元350年至公元500年和1350年至1400年，若间地区降水较多，但海平面没有上升，中国气候干燥凉爽。在此基础上，对马海峡周围海平面上升，对马洋流在中国和日本海沿岸温暖气候开始之前强烈流入日本海。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。较少

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