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西北干旱区河西走廊东段、石羊河终闾湖泊边缘的三角城剖面全新世早期至末次冰消期 2 92— 6 0 0cm处 15 5个样孢粉组合 ,显示云杉、圆柏属含量极高 ,两者之和达 40 %— 6 0 % ,且百分比互为消长。云杉百分比与孢粉浓度、植被分异度成正比。通过对云杉、圆柏属生态习性、传播性能、与其它组分关系、当地特殊的自然地理条件的综合分析 ,笔者认为剖面中高含量的云杉、圆柏属来自流域上游祁连山 ,是石羊河搬运的结果 ,孢粉组合中其它成分有当地的 ,也有来自山上的。剖面附近表土花粉分析支持这种观点。云杉、圆柏属是判断流域环境变化的主要因子 ,孢粉组合中其它成分可辅助判断环境变化的细节。流域环境重建模式和具体的变化过程是 :孢粉组合中的主要成分指示流域山上的植被状况 ;云杉花粉含量高时 ,流域有效湿度大 ,山上云杉林范围扩大 ,终闾区湖泊发育 ,整个流域生物分异度、密度 ,孢粉浓度都大 ;圆柏属花粉含量高 ,流域干旱 ,山上云杉林范围急剧减少 ,整个流域生物分异度、密度减小 ,孢粉浓度降低。圆柏属受干旱影响较小 ,数量有所减少 ,但因补偿递减率的作用 ,百分比增加。这可为重建我国西部干旱区湖泊孢粉记录的古环境作参考。
In the eastern section of the Hexi Corridor in the northwest arid section, the Triangle section near the edge of the lake at the end of the Shiyang River, 15 5 sporopollen assemblages at the interval of 92- 600 cm from the Early Holocene to the last stage of ice expulsion show that spruce and juniper Extremely high, the sum of the two reached 40% - 60%, and the percentage of each other up and down. The percentage of spruce is proportional to the sporopollen concentration and the degree of vegetation differentiation. Through the comprehensive analysis of the ecological habits of spruce, juniper, propagation and other components and the local special natural and geographical conditions, the authors believe that the high content of spruce and juniper in the profile comes from the Qilian Mountains in the upper reaches of the basin, As a result of river handling, other components of the sporopollen assemblage are local and also from the hills. Surface pollen analysis near the profile supports this view. Spruce, juniper is to determine the basin environmental changes in the main factors, other components of the spore-pollen assemblage can help determine the details of environmental changes. The pattern of basin environmental rebuilding and the specific process of change are as follows: The main components in the sporopollen assemblage indicate the vegetation status in the basin; when the pollen content of spruce is high, the effective humidity in the basin is large; the range of spruce forest in the mountain expands and the lake in the terminal area develops; The biological diversity, density and sporo-pollen concentration of the whole basin are large. The pollen content of Sabina is high, the drought area of the Sabina and the spruce forest in the mountain area are drastically reduced. The biological diversity and density of the whole basin are reduced and the spore pollen concentration is reduced. Juniperus is less affected by the drought, the number has decreased, but due to the role of compensatory decline rate, the percentage increases. This can be used as a reference for rebuilding the ancient environment recorded by sporopollen in lakes in arid areas of western China.