赣南宁都地区变质岩离子吸附型稀土矿床地球化学特征及找矿意义  

Geochemistry characteristics of ion-absorbed rare earth deposits in low-grade metamorphic rock in the Ningdu area,southern Jiangxi Province and its prospecting significance

作　　者：周雪桂 王水龙 袁承先 龚敏 邹东风 缪向亮 刘茜 ZHOU Xue-gui;WANG Shui-long;YUAN Cheng-xian;GONG Min;ZOU Dong-feng;MIAO Xiang-liang;LIU Xi(Geology and Mineral Resource Exploration and Development Center of Jiangxi Province,Nanchang 330030,China)

机构地区：[1]江西省地矿资源勘查开发中心,南昌330030

出　　处：《华东地质》2018年第3期194-201,共8页East China Geology

基　　金：江西省地质矿产勘查开发局"赣南变质岩风化壳离子型稀土矿成矿规律与资源潜力评价(编号:赣地矿办发[2013]70号)"项目资助

摘　　要：赣南浅变质岩离子吸附型稀土矿床是江西省近些年来新发现的稀土矿类型。文章主要研究赣南地区新元古代青白口纪库里组和神山组浅变质岩稀土矿点,通过野外地质调查和室内综合研究,总结了该类稀土矿床的地球化学特征。结果表明:该区浅变质岩以SiO_2含量中等、K_2O/Na_2O值较高、全碱含量中等、TFe_2O_3+MgO及CaO较低为特点;稀土元素总量较高,轻、重稀土元素分馏明显,轻稀土富集,Eu中等亏损,部分矿点已达到化学风化晚期阶段;各矿点风化壳的稀土元素配分模式与原岩类似,稀土元素富集程度主要受控于原岩稀土元素丰度和风化指数CIA。Ion-absorbed rare earth deposits in low-grade metamorphic rock are new-type rare earth deposits found recently in Jiangxi Province. This study mainly focused on Neoproterozoic low-grade metamorphic rocks of the Shenshan and Kuli Formations in southern Jiangxi Province. Based on field geological survey and experimental tests, the geochemical characteristics of the deposits of this kind were summarized. The low-grade metamorphic rocks in the study area are characterized by moderate SiO 2 and total alkalicontents , high K 2O/Na 2O ratios, low TFe 2O 3＋MgO and CaO contents. They show high total ΣREE and ΣLREE, distinct LREE/HREE fractionation, as well as moderate Eu depletion. This study shows that parts of occurrences have been at the late stage of chemical weathering. Besides, the weathering crust in each rare earth ores display similar REE distribution patterns as their protoliths. The enrichment degree of REEs depends mainly on REE abundances and CIA values of protoliths. And weathering crust inherits the REE patterns of the protolith.

关 键 词：地球化学特征 离子吸附型稀土矿床 浅变质岩 宁都地区 赣南 

分 类 号：P588.3[天文地球—岩石学] P618.7[天文地球—地质学]