Measurements on modern soil color suggest well functional relationships between the soil formation process and the present climatic factors. The redness and yellowness of soil are chiefly caused by the contents of hem...Measurements on modern soil color suggest well functional relationships between the soil formation process and the present climatic factors. The redness and yellowness of soil are chiefly caused by the contents of hematite and fullonite, and their correlations to climate are the best in humid regions in tropic and warm temperate regions. The lightness of soil mainly correlates to the organic accumulation, humification and carbonatization processes, and its correlation to climate can only be found in the humid-arid extratropical belt. The humidity and surface roughness of soil have so strong influence on soil color that there are great errors on the measurement of colorness in the field. The study on soil colors of typical loess sections shows that soil color can record the characteristics of Asia monsoon and the global climatic fluctuations well at millennial and ten-thousand-year scales. It can also indicate the pedogenesis and the climatic characteristics which magnetic susceptibility could not be展开更多
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...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.展开更多
基金the Cadreman Teachers Foundation, the Hundred Talents Project of CAS and the National Key Projects for Basic Research on the Tibetan Plateau (Grant No. G1998040809).
文摘Measurements on modern soil color suggest well functional relationships between the soil formation process and the present climatic factors. The redness and yellowness of soil are chiefly caused by the contents of hematite and fullonite, and their correlations to climate are the best in humid regions in tropic and warm temperate regions. The lightness of soil mainly correlates to the organic accumulation, humification and carbonatization processes, and its correlation to climate can only be found in the humid-arid extratropical belt. The humidity and surface roughness of soil have so strong influence on soil color that there are great errors on the measurement of colorness in the field. The study on soil colors of typical loess sections shows that soil color can record the characteristics of Asia monsoon and the global climatic fluctuations well at millennial and ten-thousand-year scales. It can also indicate the pedogenesis and the climatic characteristics which magnetic susceptibility could not be
文摘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.
