【摘要】 通过对长江三峡库区不同母岩上发育的紫色土样品进行X射线荧光光谱的化学全量分析及化学蚀变指数CIA值、风化特征值和质量迁移系数的详细计算,揭示了不同母岩上发育的紫色土化学风化强度和主量元素的迁移特征:母岩为砂岩发育的紫色土具有较高的CIA值,母岩为粉砂岩和泥岩上发育的紫色土的CIA值较低;不同元素组分迁移行为在剖面上的表现有明显的差异,CaO在所有剖面上净迁出,多数剖面均有Al2O3、Fe2O3的净获得;母岩为砂岩发育的紫色土剖面上Ca、K、Na、Al、Fe、Si6种元素均流失,而粉砂岩、泥岩发育的紫色土以上6种元素相对富积,Mg元素的迁移系数远小于Ca元素,其迁移性较小,在母岩和土壤中的含量相对稳定;Na元素的迁移系数较大,迁移速率较快.更多还原

【Abstract】 Geochemical compositions of 30 purple soil samples in the Three Gorges area were awalyzed. The Chemical Index of Alteration （CIA） of the purple soil that developed in basal rocks of sandstone is high, while the CIA of the purple soil that developed in basal rock of mudstone and siltstone is low. The CaO contents are lost in all sections but the Al₂O₃ and Fe₂O₃ contents remain constant. The contents of Ca, K, Na, Mg, Al, Si are lost for those formed in basal rocks of sandstone but enriched for those formed in basal rocks of mudstone and siltstone. The transference of Mg element is weak but that of Na element is intense. So Na element transfers fast than Mg element.更多还原