Based on the tree ring width index of Pinus tabulaeformis, precipitation in the last 140 years was recon-structed at south margin of the Tengger Desert. The results indicated that there were obvious fluctuations of dr...Based on the tree ring width index of Pinus tabulaeformis, precipitation in the last 140 years was recon-structed at south margin of the Tengger Desert. The results indicated that there were obvious fluctuations of dry-wet changes in precipitation: two wet periods occurred during 1868―1876 and 1932―1939, and two dry periods during 1877―1894 and 1924―1932, however, the years 1887 and 1888 were a little wet. There were small changes in precipita-tion during 1895―1923 and 1940―2000. As compared to the average, the maximum increasing range of precipitation amounted to 56% during the wet periods, and 42% during the dry periods. And the range of variability of precipitation exceeded 30% in 19 years. There was no obvious consistent drying or wetting trend in the last 140 years. But since 1940 fluctuating scope of precipitation tended to be smaller, while the frequency of the fluctuation tended to be larger. Power spectrum analyses suggested that precipitation of south mar-gin of the Tengger Desert had significant periodicities of 2.46―2.64 a and quasi periodicity of 11.67 a.展开更多
为探讨腾格里沙漠南缘末次冰消期的气候演变,通过测量土门剖面52L～41FD层段的6个测年样品的年代和83个常规样品的微量元素的质量分数,分析了土门剖面微量元素特征反映的该地区末次冰消期的古气候环境变化.分析结果表明:微量元素按其质...为探讨腾格里沙漠南缘末次冰消期的气候演变,通过测量土门剖面52L～41FD层段的6个测年样品的年代和83个常规样品的微量元素的质量分数,分析了土门剖面微量元素特征反映的该地区末次冰消期的古气候环境变化.分析结果表明:微量元素按其质量分数从高到低依次为Mn、P、Sr、Rb、Cr、V、Zn、Ni、Cu、Nb,各元素的质量分数在砂黄土、古土壤和湖相沉积中表现为相对峰态,而在沙丘砂层段中表现为相对谷态;在垂直方向上,各微量元素的质量分数随着各沉积相的多次更替,构成了10条峰谷交替的锯齿状形态的元素波动过程线;结合研究区地理位置与微量元素特征,以Zn、P的质量分数为代表的气候替代性指标指示本区东亚冬、夏季风变化,据此划分出了8个冷暖波动事件:"冷干事件"C1(11 870～11 640 a BP)、C2(12 650～12 050 a BP)、C3(13 340～13 010 a BP)、C4(13 810～13 620 a BP),"暖湿事件"W1 (12 050～11 870 a BP)、W2 (13 010～12 650 a BP)、W3 (13 620～13 340 a BP)、W4(14 850～13 810 a BP).本研究与格陵兰GRIP冰芯和中国南京葫芦洞H82石笋之间较高的同步性表明:腾格里沙漠南缘末次冰消期的气候波动可能受北半球的高纬动力驱动.展开更多
腾格里沙漠南缘土门剖面末次冰消期层段由3层沙丘砂、2层湖相沉积、2层古土壤和5层黄土构成。主元素氧化物中，Si02含量在沙丘砂层呈现峰态，而在黄土、湖相沉积及古土壤呈现谷态；A1203、TFe（Fe203＋FeO）、CaO、MgO、Na20、K20和TiO...腾格里沙漠南缘土门剖面末次冰消期层段由3层沙丘砂、2层湖相沉积、2层古土壤和5层黄土构成。主元素氧化物中，Si02含量在沙丘砂层呈现峰态，而在黄土、湖相沉积及古土壤呈现谷态；A1203、TFe（Fe203＋FeO）、CaO、MgO、Na20、K20和TiO2则在沙丘砂层呈现为谷，在黄土、湖相沉积及古土壤中呈现为峰，Si02分别与A1203等氧化物在垂直方向上呈镜像对称。结合研究区地形，对元素氧化物特征分析后，认为可用硅铝比高低变化指示本区东亚冬夏季风变化。划分出了9个冷暖波动事件，按时间先后依次为：C5（14930-14847 a BP）、W4（14847-13810 a BP）、C4（13810-13620 a BP）、W3（13620-13340 a BP）、C3（13340-13010 a BP）、W2（13010-12650 a BP）、C2（12650-12050 a BP）、W1（12050-11860 a BP）和C1（11860-11600 a BP）。本研究层段与格陵兰GRIP冰芯及南京葫芦洞石笋记录的末次冰消期冷暖变化有较高的相似性，可能本区末次冰消期季风气候变化受北半球高纬驱动。展开更多
基金supported by the Na tional Natural Science Foundation of China(Grant No.40271114)the Specialized Research Fund for the Doctoral Program of Higher Educa-tion of China(Grant No.20040027024)the National Key Projects for Basic Scientific Research(Grant No.G2000048701).
文摘Based on the tree ring width index of Pinus tabulaeformis, precipitation in the last 140 years was recon-structed at south margin of the Tengger Desert. The results indicated that there were obvious fluctuations of dry-wet changes in precipitation: two wet periods occurred during 1868―1876 and 1932―1939, and two dry periods during 1877―1894 and 1924―1932, however, the years 1887 and 1888 were a little wet. There were small changes in precipita-tion during 1895―1923 and 1940―2000. As compared to the average, the maximum increasing range of precipitation amounted to 56% during the wet periods, and 42% during the dry periods. And the range of variability of precipitation exceeded 30% in 19 years. There was no obvious consistent drying or wetting trend in the last 140 years. But since 1940 fluctuating scope of precipitation tended to be smaller, while the frequency of the fluctuation tended to be larger. Power spectrum analyses suggested that precipitation of south mar-gin of the Tengger Desert had significant periodicities of 2.46―2.64 a and quasi periodicity of 11.67 a.
文摘为探讨腾格里沙漠南缘末次冰消期的气候演变,通过测量土门剖面52L～41FD层段的6个测年样品的年代和83个常规样品的微量元素的质量分数,分析了土门剖面微量元素特征反映的该地区末次冰消期的古气候环境变化.分析结果表明:微量元素按其质量分数从高到低依次为Mn、P、Sr、Rb、Cr、V、Zn、Ni、Cu、Nb,各元素的质量分数在砂黄土、古土壤和湖相沉积中表现为相对峰态,而在沙丘砂层段中表现为相对谷态;在垂直方向上,各微量元素的质量分数随着各沉积相的多次更替,构成了10条峰谷交替的锯齿状形态的元素波动过程线;结合研究区地理位置与微量元素特征,以Zn、P的质量分数为代表的气候替代性指标指示本区东亚冬、夏季风变化,据此划分出了8个冷暖波动事件:"冷干事件"C1(11 870～11 640 a BP)、C2(12 650～12 050 a BP)、C3(13 340～13 010 a BP)、C4(13 810～13 620 a BP),"暖湿事件"W1 (12 050～11 870 a BP)、W2 (13 010～12 650 a BP)、W3 (13 620～13 340 a BP)、W4(14 850～13 810 a BP).本研究与格陵兰GRIP冰芯和中国南京葫芦洞H82石笋之间较高的同步性表明:腾格里沙漠南缘末次冰消期的气候波动可能受北半球的高纬动力驱动.
文摘腾格里沙漠南缘土门剖面末次冰消期层段由3层沙丘砂、2层湖相沉积、2层古土壤和5层黄土构成。主元素氧化物中，Si02含量在沙丘砂层呈现峰态，而在黄土、湖相沉积及古土壤呈现谷态；A1203、TFe（Fe203＋FeO）、CaO、MgO、Na20、K20和TiO2则在沙丘砂层呈现为谷，在黄土、湖相沉积及古土壤中呈现为峰，Si02分别与A1203等氧化物在垂直方向上呈镜像对称。结合研究区地形，对元素氧化物特征分析后，认为可用硅铝比高低变化指示本区东亚冬夏季风变化。划分出了9个冷暖波动事件，按时间先后依次为：C5（14930-14847 a BP）、W4（14847-13810 a BP）、C4（13810-13620 a BP）、W3（13620-13340 a BP）、C3（13340-13010 a BP）、W2（13010-12650 a BP）、C2（12650-12050 a BP）、W1（12050-11860 a BP）和C1（11860-11600 a BP）。本研究层段与格陵兰GRIP冰芯及南京葫芦洞石笋记录的末次冰消期冷暖变化有较高的相似性，可能本区末次冰消期季风气候变化受北半球高纬驱动。
