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陕西洛川黑木沟黄土剖面中碳酸盐的87Sr/ 86Sr比值从 0 .71 0 4变化到 0 .71 2 0 ,其中古土壤碳酸盐的Sr同位素比值一般比黄土的高 .在剖面上 ,Sr同位素比值的变化显示人们所熟悉的 1 0 0ka左右的冰期 间冰期循环周期 ,而且与相同时期古海水的Sr同位素组成变化相似 .这一研究结果说明黄土中碳酸盐的Sr同位素组成变化可以指示风化程度和古气候的变化 ,古海水Sr同位素组成的周期变动主要是大陆地壳物质风化作用程度变化的结果 .
The 87Sr / 86Sr ratio of carbonates in the Heiqingou loess section of Luochuan, Shaanxi Province changed from 0.71 0 4 to 0 .71 2 0, in which the Sr isotopic ratio of carbonate in the ancient soil was generally higher than that in the loess. The change of Sr isotopic ratio shows the familiar glacial cycle of about 100 ka during glacial period and similar to the change of Sr isotopic compositions of paleo-seawater at the same period.The results of this study show that Sr isotopic composition of carbonate in loess Can indicate the degree of weathering and paleoclimate changes. The periodic variation of Sr isotope composition of pale-sea water is mainly the result of changes in the degree of weathering of continental crustal material.