广东韶关红岭黑云母花岗岩和离子吸附型稀土矿床地球化学特征  

Geochemical characteristics of Hongling biotite granite and ion-adsorbed rare earth deposits in Shaoguan,Guangdong

作　　者：郭敏 黄玲玲 孙社良 黄孔文 贺强翔 向安平 GUO Min;HUANG Linlin;SUN Sheliang;HUANG Kongwen;HE Qiangxiang;XIANG Anping(Guangdong Geological Survey Institute,Guangzhou 510080,China;Chengdu Center,China Geological Survey(Geosciences Innovation Center of Southwest China),Chengdu 611230,China)

机构地区：[1]广东省地质调查院,广州510080 [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),成都611230

出　　处：《成都理工大学学报（自然科学版）》2024年第4期561-578,595,共19页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：广东省地质勘查与城市地质专项项目广东省稀土资源调查评价(2022-14);国家自然科学基金项目(41802095)。

摘　　要：离子吸附型稀土矿产是中国优势资源,对其开展深入的研究,有助于提升中国关键金属资源的安全保障程度。对广东韶关红岭地区新发现的离子吸附型稀土矿床的钻孔中的风化壳剖面和深部的新鲜黑云母花岗岩开展了全岩主量元素、微量稀土元素和锆石U-Pb年代学分析,旨在查明成矿母岩的地球化学特征和稀土元素在风化壳中的富集特征。新鲜花岗岩的锆石U-Pb年龄为(162.0±0.5)Ma。红岭花岗岩的SiO_(2)(平均值为73.73%)、Al_(2)O_(3)、K_(2)O质量分数和A/CNK值均较高(平均值为1.2),属于钙碱性岩浆岩;结合微量元素特征,红岭岩体起源于下地壳变沉积岩部分熔融形成的S型花岗岩。红岭花岗岩稀土元素总量较高(平均值为225.3×10^(-6)),是形成离子吸附型稀土矿的优质物源。从表土层、全风化层到半风化层,稀土元素质量分数由小到大再变小。风化层的稀土元素质量分数整体较高,平均值为608.9×10^(-6);轻/重稀土元素比值平均为5.5,属于轻稀土元素富集型。风化层中的稀土元素继承了深部花岗岩的地球化学特征。花岗岩的稀土元素质量分数较高,并且风化层中高的化学蚀变指数表明研究区具有较好的离子吸附型稀土矿的找矿潜力。China is rich in ion-adsorbed rare earth deposits and their extensive study can help secure key metal resources for the country.In this study,we analyze the weathered crust section of the newly discovered ion-adsorbed rare earth deposit in the Hongling area of Shaoguan,in the Guangdong Province of China,and examine the fresh granite,trace elements,and zircon U-Pb chronology of the whole-rock major elements.The aim is to identify the geochemical characteristics of the ore-forming bedrock and the mechanism of enrichment of rare earth elements in the weathered crust.The zircon U-Pb age of Hongling biotite monzonite was(162.0±0.5)Ma,which is consistent with the metallogenic age of tungsten-tin rare metals in the Nanling area.The Hongling granite had high contents of SiO_(2)(average,73.73%),Al_(2)O_(3),K_(2)O,and A/CNK(average,1.2),and was classified as calc-alkaline magmatic rock.This,combined with the characteristics of the trace elements,led us to determine that the Hongling pluton had originated from S-type granite formed by the partial melting of metasedimentary rocks in the lower crust.The Hongling granite also had a high content of rare earth elements(average,225.3×10^(-6)),which constitute a high-quality source for the formation of ion-adsorbed rare earth minerals.The content of rare earth elements increased from low to high,and then decreased from the topsoil layer,the upper part of the total regolith,and the lower part of the regolith to the semi-regolith.The content of rare earth elements in the regolith was relatively high on the whole,with an average value of 608.9×10^(-6).The average ratio of light to heavy rare earth elements was 5.5,and they were classified as enriched and light rare earth elements.The rare earth elements in the regolith of the Hongling area had inherited the geochemical characteristics of fresh Hongling granite.The latter had a high content of rare earth elements,while the high chemical alteration index of the regolith suggests that the study area had good ore-prospecting potential

关 键 词：黑云母花岗岩 离子吸附型稀土矿 岩石成因 南岭 广东韶关 

分 类 号：P595[天文地球—地球化学]