摘要
中国黄土和南极冰芯各自记载了15万年以来环境演化的信息,通过两者的对比研究,可以揭示全球性环境变化的普遍特征和区域特点。对比表明:15万年以来,中国甘肃临夏北塬黄土剖面中磁化率反映的气候变化与南极Vostok站冰芯中δD反映的温度变化趋势非常相似,在以万年计的时间尺度内,所反映的气候变化趋势是一致的,但相同时段两者的变化幅度,特别是在距今14～8万年的末次间冰期期间,差别较大。
The information of environmental changes for past 150,000 years have been recorded by both of Chinese loess deposits and deep Antarctic ice core. The research of comparing the records from these two different kinds of sediments can reveal the common characteristics of global palaeoclimatic changes and local features.
Recent research showes, due to larger deposit rate, more paleosol layers, high sensibility and good distinguishability in revealing environmental changes, the Beiyuan loess profile, at Linxia, China, is a model record of environmental change for past 150,000 years (Fig. 1, 2, 3). According to the distribution of loess and paleosols, the profile can be divided into several stratal units, i.e. S0<8,500 a.B.P. ; L1-1, 25,000-8,500 a.B.P. ; Sm, 53,000-25,000 a.B.P.; L1-2, 80,000-53,000 a.B.P.; S1; 140,000-80,000 a.B.P.; L2 >140,000 a.B.P..Among these, stage Sm was composed of three weak pedogenic paleosol layers with two loess in between, stage S1; including three paleosol layers of drab soil type and two loess layers, L1-2, contained two weak weathering layers. The measure of the magnetic susceptibility shows (Fig. 4), the magnetic susceptibility of paleaosol layers is much more high than that of loess layers; the magnetic susceptibility of loess layers are about 20 C. G. S., that of paleosol layers in Sm stage is as 1.5 times as loess layers and that in S0 and S1 is 3-4 times more than loess layers. Pollen analysis at Beiyuan profile reveals the concentration of pollen is high in paleosols and low in loess. There is proper amount lignosa at paleosols, but, in loess most of all was herb. At the stage from paleosol to loess, the dark coniferous forest major with pine, dragon spurce and fir were largely developed.
Comparing the record of Beiyuan loess at Linxia, China with that of Vostok ice core at Antarctic, we can find the two records are very analogous in revealing general tendency of environmental changes (Fig. 5). The stage L2 of Beiyuan profile corresponds to stage H of Vostok ice
出处
《南极研究》
CSCD
1991年第3期15-24,共10页
基金
国家自然科学基金
国家教委博士点基金的资助
关键词
黄土
冰芯
磁化率
孢粉
南极
中国
Chinese loess, Antarctic ice cores, magnetic susceptibility, pollen, δD
