摘要
Our research group have investigated chronology and sedimentology of terrestrialsediments including loess-paleosols sediments over the last 75 ka at Lanzhou, northwestern China,and over the last 45ka at Tokyo, central Japan. Based on chronology of high resolution dating ofESR, TL, and IRSL and tephrochronology in these sediments, we investigated to reconstructactivities of Asian summer and winter paleomonsoons by using magnetic susceptibility, colorreflectance and eolian dust concentrations over the last 75ka. Relations between standard curves ofdelta <sup>18</sup>O in GISP2 and color reflectance in loess-paleosol sediments of Linxia over last 140 kashows that color reflectances are good proxy records indicating Asian summer paleomonsoonactivity in time and are closely related to standard curve of delta <sup>18</sup>O in GRIP since the lastinterglacial. Also, relations between standard curve of delta <sup>18</sup>O in GISP2 and eolian dustconcentrations over the last 75 ka at Lanzhou shows the Asian winter paleomonsoon activitieshave coincided with climatic changes in North Atlantic by GISP2 ice cores, and suggests thatresponse of winter monsoon was rapid in global cooling stages, but slow in warming stage. Otherresults of our research in terrestrial sediments show as follows; 1) Horizons of Heinrich eventsfrom H1 to H4 in loess-paleosol sequences at Lanzhou. 2) Magnetic susceptibility and MSfrequency dependent are possible to be available as proxy records for pedogenesis of tile KantoLoam in Japan. 3) 8.2ka cooling event was recognized in Holocene loess-paleosol sequences atLanzhou.
Our research group have investigated chronology and sedimentology of terrestrial sediments including loess-paleosols sediments over the last 75 ka at Lanzhou, northwestern China, and over the last 45ka at Tokyo, central Japan. Based on chronology of high resolution dating of ESR, TL, and IRSL and tephrochronology in these sediments, we investigated to reconstruct activities of Asian summer and winter paleomonsoons by using magnetic susceptibility, color reflectance and eolian dust concentrations over the last 75ka. Relations between standard curves of delta ^(18)O in GISP2 and color reflectance in loess-paleosol sediments of Linxia over last 140 ka shows that color reflectances are good proxy records indicating Asian summer paleomonsoon activity in time and are closely related to standard curve of delta ^(18)O in GRIP since the last interglacial. Also, relations between standard curve of delta ^(18)O in GISP2 and eolian dust concentrations over the last 75 ka at Lanzhou shows the Asian winter paleomonsoon activities have coincided with climatic changes in North Atlantic by GISP2 ice cores, and suggests that response of winter monsoon was rapid in global cooling stages, but slow in warming stage. Other results of our research in terrestrial sediments show as follows; 1) Horizons of Heinrich events from H1 to H4 in loess-paleosol sequences at Lanzhou. 2) Magnetic susceptibility and MS frequency dependent are possible to be available as proxy records for pedogenesis of tile Kanto Loam in Japan. 3) 8.2ka cooling event was recognized in Holocene loess-paleosol sequences at Lanzhou.
