广西某地花岗岩风化壳中稀土元素特征与iREE矿床成矿机制

发布时间：2018-03-07 05:10

本文选题：风化壳剖面　切入点：稀土元素　出处：《地球科学》2017年10期 　论文类型：期刊论文

【摘要】：为了解风化壳中离子交换相稀土元素的特征,对广西某地花岗岩风化壳剖面样品进行了X射线衍射及主量、稀土元素地球化学特征的研究.剖面自上而下可划分为腐殖土层(A1)、亚粘土层(A2)、网纹状风化层(B1)和全风化层(B2);自A1至B2,粘土矿物的含量和化学风化蚀变指数快速降低;与母岩相比A1、A2、B1中全相Ce、Nd和HREE相对富集,B2中全相稀土与母岩特征相似,所有样品的离子交换相HREE亏损,Y相对富集;离子交换相轻、重稀土一起富集在B2中.据此推测,花岗岩中褐帘石、榍石等易风化的稀土矿物为离子交换相稀土提供了主要的物源,锆石、磷钇矿等难风化的稀土矿物的残留及表生稀土矿物的形成使全相HREE相对富集;离子交换相轻、重稀土元素的分馏程度随风化程度的增加而变化.
[Abstract]:In order to understand the characteristics of ion exchange phase rare earth elements in weathered crust, X-ray diffraction and principal amount were carried out on the samples of weathered crust section of granite in Guangxi. From top to bottom, the profile can be divided into humic soil layer (A1), subclay layer (A2), reticulate weathering layer (B1) and total weathering layer (B2), and from A1 to B2, the content of clay minerals and chemical weathering alteration index decrease rapidly. Compared with the parent rocks, the relative enrichment of the whole phase Cendd and HREE in the A1CU A2B1 and HREE is similar to the characteristics of the parent rocks, the HREE depletion of all samples is relatively enriched, the ion exchange phase is light and the heavy rare earth is enriched in B2. The weathering rare earth minerals such as cinnamon and sphene in granites provide the main material source for the ion exchange phase rare earths. The residual of refractory rare earth minerals such as zircon and yttrium phosphate ore and the formation of epigenetic rare earth minerals make the whole phase HREE relatively enriched. The fractionation degree of heavy rare earth elements changes with the increase of weathering degree.
【作者单位】：国土资源部成矿作用与资源评价重点实验室中国地质科学院矿产资源研究所;广西壮族自治区地质调查院;国家地质实验测试中心;
【基金】：中央级公益性科研院所基本科研业务费专项资金(No.K1506) 中国地质调查局地质大调查项目(No.DD20160056)
【分类号】：P618.7

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