金华市表层土壤Rb/Sr分布特征及环境指示意义

The distribution and the environmental implications of rubidium and strontium ratio of Jinhua soil

以金华市为研究区域,共采集了518个表层土壤样品,对样品中铷(Rb)元素和锶(Sr)元素的含量进行了测定与分析.测定结果为:金华市表层土壤中Rb的平均含量为122.70 mg/kg,变异系数为35%;而Sr的平均含量为75.50 mg/kg,变异系数为60%.结果表明:金华市表层土壤中Rb含量略高于Sr含量,而Sr含量的空间变异性高于Rb含量,与Sr元素相比,Rb元素具有更好的风化稳定性;表层土壤中Rb/Sr含量比的空间分布规律较为明显,总体上呈现由西南向东北降低的趋势,与金华市的年均降水量具有较好的一致性.Rb/Sr含量比与年均降水量呈较强的正相关关系,进一步表明Rb/Sr含量比可以用来指示亚热带季风区的降水量.最后,建立了Rb/Sr含量比与年均降水量的回归关系式,可初步用于反演古环境的降水量.

Taking Jinhua as the study area, the surface soil was sampled, then X-fluorescence spectroscopy was used to analyze Rb and Sr in the soil, GIS technology was used to analyze the relationship of the average annual precipitation of Jinhua and the spatial distribution of Rb/Sr of Jinhua soil. The result showed that the average content of Rb was 122.70 mg/kg, coefficient of variation was 35%, and the average content of Sr was 75.50 mg./kg, coefficient of variation was 60%. The average content of Rb was higher than Sr, and had a lower spatial variation than Sr. The spatial distribution of Rb/Sr decreased form southwest to northeast, and was more like the distribution of average annual precipitation. The average annual precipitation of Jinhua and Rb/Sr ratios showed a positive relationship, that proved .the Rb/Sr ratios could take as the indicator of precipitation. The regression model was given to calculate the precipitation in the climate study.