吴起全新世土壤剖面常量元素地球化学特征

Geochemical Characteristics of Major Elements of Holocene Soil from Wuqi, Shaanxi Province

土壤的化学成分不但与化学风化作用有关,还与其物源的化学组成紧密相关。对来自于陕西省吴起县城南偏东17 km的土壤剖面(0~1.6 m)进行年代学和化学元素分析,探讨吴起土壤剖面的时代、成因、物源及化学风化程度。14C年代学结果表明吴起土壤剖面为全新世时期形成的黑垆土;化学元素组成的高度一致性、UCC标准化曲线及元素比值与典型风成沉积物趋势总体接近佐证了吴起土壤剖面的风成成因;化学风化程度研究显示吴起土壤剖面处于初等弱风化阶段和去Na、Ca阶段;示踪元素比值分布指示吴起土壤剖面与洛川古土壤、灵台古土壤、灵台红粘土、镇江下蜀土存在相似的源区。

The composition of the sediment depends on the chemical weathering and the chemical composition of the source.In order to discuss the age,genesis,provenance and degree of chemical weathering,the chronology and chemical elements analyses were carried out on the samples from the soil sequence in Wuqi County,Shaanxi Province and compared with typical aeolian sediments.The results of the14 C chronology show that the Wuqi soil profile was formed during the Holocene period.The high consistency of chemical composition,UCC-normalized diagram and element ratio with the trend of typical aeolian sediments are close to the evidence of the aeolian genesis of Wuqi soil profile.The chemical weathering intensity study shows that the Wuqi soil profile is in the primary weak weathering stage and the removal of Na and Ca stages.The trace element ratio distribution indicates that the Wuqi soil profile is similar to that of Luochuan paleosol,Lingtai paleosol,Lingtai red-clay and Zhenjiang Xiashu soil.