【摘要】 对南京老虎山黄土-古土壤剖面全样和三个粒级组分(<2μm、2～45μm和>45μm)的Rb/Sr比值进行了系统研究。结果表明,Rb/Sr比值是衡量黄土和古土壤化学风化强度的良好地球化学指标;粒度分组是利用Rb/Sr比值研究古环境变化的有效方法。通过粒度分组,可以排除不同粒度组分之间由于Rb/Sr初始比值不同造成的互相干扰。<2μm粒级的(Rb/Sr)-Sr反相关图的R2值最大(达0.97),说明该粒级指示化学风化作用的灵敏度最高,研究Rb/Sr比值这一地球化学指标最理想。更多还原

【Abstract】 Rb and Sr contents and Rb/Sr ratios of bulk samples and three subpopulation of different size (< 2 μm, 2 to 45 μm and >5 μm, respectively) are analyzed for both loess and paleosol layers of the Laohushan profile, Nanjing, China. The results indicate that variation in Rb/Sr ratio can be served as an effective geochemical indicator of chemical weathering intensity of loess and paleosol, and that grain size subpopulation is a helpful method for defining paleoenvironmental change, because individual subpopulation may be minimized varying initial Rb/Sr ratios from size to size. Negative correlation between Rb/Sr ratios and Sr contents of < 2 μm fraction with R2=0.97 may imply that this size is sensitive to intensity of chemical weathering and is an ideal subpopulation for proxy of Rb/Sr ratio.更多还原