川西德昌馒头山离子吸附型重稀土矿床的发现及其地质意义  

The discovery and geological significance of the Mantoushan ion-adsorption type heavy rare earth deposit in Dechang,western Sichuan

作　　者：郭金承 聂飞[1,2] 吴松洋 刘洪 邹佳作 冉光辉 雷栋 来永革 GUO Jincheng;NIE Fei;WU Songyang;LIU Hong;ZOU Jiazuo;RAN Guanghui;LEI Dong;LAI Yongge(Civil-military Integration Center of Geological Survey,China Geological Survey,Chengdu 610036,China;Chengdu Center,China Geological Survey(Geosciences Innovation Center of Southwest China),Chengdu 610218,China)

机构地区：[1]中国地质调查局军民融合地质调查中心,四川成都610036 [2]中国地质调查局成都地质调查中心(西南地质科技创新中心),四川成都610218

出　　处：《沉积与特提斯地质》2024年第1期86-99,共14页Sedimentary Geology and Tethyan Geology

基　　金：攀西冕宁—德昌地区稀土及多金属矿产地质调查(DD20220965)。

摘　　要：冕宁—德昌稀土成矿带是我国重要硬岩型稀土资源基地,已发现的稀土资源均与喜马拉雅期形成的碳酸岩-碱性杂岩体有关,作者在该地区开展地质调查时在德昌馒头山新发现了与二叠纪晚期钾长花岗岩相关的离子吸附型稀土矿床,因此,本文通过对德昌馒头山地区开展矿产地质调查,经3个浅钻验证,该地区风化壳厚度最深可达17 m,并根据风化程度将风化壳由地表至基岩,依次划分为腐殖土层、黏土层、全风化层和半风化层,风化壳全相稀土氧化物品位(TREO)变化范围为0.07%~0.19%,平均为0.12%,高于工业品位的0.05%;离子相稀土氧化物(SREO)品位变化范围为0.02%~0.056%,平均为0.03%,高于边界品位的0.02%;重稀土配分范围为50%~72%,平均为62%。稀土品位变化在风化壳剖面呈现出“上低—下高”和“上高—下低”两种类型,全风化层和黏土层是主要赋矿层位。这是首次在冕宁—德昌稀土成矿带发现离子吸附型重稀土矿,具有重大经济价值和科学意义。The Mianning-Dechang rare earth metallogenic belt is one of the most important rare earth resource areas in China.All discovered rare earth deposits are related to the carbonatite-alkaline complex that formed during the Himalayan period.It is controversial whether ion adsorption rare earth deposits exist along this metallogenic belt.In this paper,we conducted a detailed survey of Mantoushan potash feldspar granite in Dechang and verified through three shallow drill coress that the thickness of the weathering crust in this area reached 17 meters.According to the degree of weathering,the weathering crust is divided into humus,clay,full regolith,and semi-regolith.The total phase rare earth oxide(TREO)grade of the regolith crust varies between 0.07%and 0.19%,with an average of 0.12%,which is higher than the industrial grade of 0.05%.Additionally,the grades of separated quantities of rare earth oxides(SREO)range between 0.02%and 0.056%,with an average of 0.03%,which is higher than the cutoff grade of 0.02%.The partition range of heavy rare earth is between 50%and 72%,averaging at 62%.The variation of rare earth grade within the weathering crust profile exhibits two patterns:"upper low-lower high"and"upper high-lower low".The full regolith and clay layers are identified as the primary ore-bearing layers for both patterns.The Mantoushan deposit is the first ion adsorption heavy rare earth ore deposit found in the Mianning-Dechang rare earth metallogenic belt,which has great economic value and scientific significance.

关 键 词：钾长花岗岩 风化作用 离子吸附型重稀土矿 川西 

分 类 号：P618.91[天文地球—矿床学]