【摘要】 为掌握黎塘富含铁锰结核土壤区碳酸盐岩稀土元素特征,对研究区岩石样品进行了采样分析,并对其形成环境进行了讨论。结果表明:研究区碎屑岩岩石样品远高于碳酸盐岩,碳酸盐岩不同地层具有一定差异,碳酸盐岩轻稀土元素之间、重稀土元素之间分馏不明显,而碎屑岩具有一定分馏特征。碳酸盐岩Y/Ho的比值以及Ce以负异常为主,表明碳酸盐岩应为海相-氧化环境,δCe与LaN/SmN、DyN/SmN的相关性表明经过了后期成岩的改造作用。碎屑岩Y/Ho的比值以及Ce基本无异常,表明碎屑岩应为湖相成因,当时沉积水体氧化还原条件基本无变化。碳酸盐岩不同地层δCe的差异,说明了氧化性随地质时期的变化,这种变化推断为后期土壤铁锰结核的形成起到了重要的作用。更多还原

【Abstract】 In order to study the geochemical characteristics of rare earth element of carbonate rocks in the Fe-Mnnodule-rich soil region in Litang,the rare earth elements( REEs) contents of rock samples were analyzed using inductively coupled plasma mass spectrometry( ICP-MS). The results showed that the total rare earth elements contents of clastic rock were higher than carbonate rock. There were differences in the concentrations of rare earth elements among carbonate rocks of different strata. It was unobvious fractionation between light rare earth element( LREEs) and heavy rare earth element( HREEs) in the carbonate rock,but there is somewhat fractionation in the clastic rock. The value of Y/Ho and negative anomaly of δCe in carbonate rock indicated that the sedimentary environment belonged to oxidation and to marine carbonatesedimentary environment,and the relations of δCe-LaN/SmN,δCe-DyN/SmNreflect the later effect of diagenesis. The value of Y/Ho and no anomaly of δCe in the clastic rock indicated that the sedimentary environment belonged to lacustrine deposit with no changing of redox conditions. The differences of δCe in the carbonate rocks showed that the oxidability was changed with geologic time. The formation of Fe-Mn nodules were attributed to changing oxidability.更多还原