摘要
滇西梁河县新发现的那俄铍矿是一含绿柱石岩浆热液伟晶岩脉型铍矿床,矿体产状多数为北东-南西向延伸,延伸走向长50~1220 m,厚度0.36~3.70 m,品位0.045%~1.79%,并伴生有铌钽铷等多种稀有金属。该矿床围岩主要为二长花岗岩、石英二长闪长岩等。二长花岗岩类SiO 2=65.02%~73.65%,Al 2 O 3=13.27%~16.80%,K 2 O/Na 2 O=1.18~2.07,A/NCK=1.05~1.15,表现出高硅、富碱、低镁铁的特点;石英二长闪长岩(花岗闪长岩)类SiO 2=51.03%~65.88%,Al 2 O 3=15.97%~18.56%,K 2 O/Na 2 O=0.57~0.86,A/NCK=0.83~1.10;花岗伟晶岩SiO 2=75.16%,Al 2 O 3=13.52%,K 2 O/Na 2 O=1.39,A/NCK=1.08,δEu=0.13~0.36,分异指数>85,与围岩差异较大,认为那俄铍矿为岩浆热液演化晚期分异结晶形成。研究区所在的勐养岩体锆石U-Pb年龄127.9±1.0~115.2±1.1 Ma,均为早白垩世。通过对研究区的区域大地构造演化、岩石地球化学和U-Pb年代学特征研究认为,那俄地区在早白垩世经历了早期陆内应力调整期、中期构造活跃期、晚期岩浆热液成矿期三个差异明显的构造-岩浆阶段,而那俄铍矿的形成则是晚期岩浆热液作用的结果。
The Na’e beryllium deposit is a newly discovered beryllite-bearing pegmatite vein type deposit which is closely related to magmatic hydrothermal fluids.The beryllium ore bodies are about 50~1220 m long,0.36 m to 3.70 m thick,mostly trending in the NE direction,with ore grade between 0.045%and 1.79%,associated with many rare metal elements such as Nb,Ta,Rb and Cs.The wall rocks of this deposit are mainly monzogranite and quartz monzogranite.The monzogranite contains SiO 2 about 65.02%~73.65%,Al 2 O 313.27%~16.80%,K 2 O/Na 2 O 1.18~2.07 and A/CNK 1.05~1.15,characterized by high silicon,rich alkali and low magnesium and iron.The granodiorite contains SiO 2 about 51.03%~65.88%,Al 2 O 3 of 15.97%~18.56%,K 2 O/Na 2 O 0.57~0.86 and A/CNK 0.83~1.10.The granite pegmatite has SiO 275.16%,Al 2 O 313.52%,K 2 O/Na 2 O 1.39,and A/CNK 1.08;with values ofδEu 0.13~0.36,and the differentiation index greater than 85,which is quite different from that of the surrounding rocks.It is considered that the Na’e beryllium deposit was formed by differential crystallization in the late stage of magmatic hydrothermal evolution.Zircon U-Pb ages of the Mengyang pluton in the study area range from 127.9±1.0 Ma to 115.2±1.1 Ma,belonging to Early Cretaceous time.Combined with regional tectonic evolution,petrochemistry and U-Pb geochronology of the study area,research suggests that the Na e area experienced three distinct tectonic magmatic stages in Early Cretaceous,i.e.,the intracontinental stress adjustment,tectonic active period and magmatic hydrothermal mineralization,and the formation of this deposit was the result of the late magmatic hydrothermal process.
作者
燕利军
王胜江
陈曹军
严志安
佘中明
邓志祥
吴清华
殷伟
YAN Lijun;WANG Shengjiang;CHEN Caojun;YAN Zhi’an;SHE Zhongming;DENG Zhixiang;WU Qinghua;YIN Wei(Yunnan Institute of Geological Survey,Kunming,Yunnan 650216;Key Laboratory of Sanjiang Metallogeny and Resources Exploration and Utilization,MNR,Kunming,Yunnan 650051;Yunnan Geological Survey Foundation Management Center,Kunming,Yunnan 650224)
出处
《地质与勘探》
CAS
CSCD
北大核心
2021年第4期739-750,共12页
Geology and Exploration
基金
云南省自然资源厅地质勘查基金项目“云南省1∶5万盈江县旧城梁河街河头村矿产地质调查”(编号:D201716)资助。
关键词
伟晶岩型铍矿
岩石地球化学
U-PB年代学
早白垩世岩浆岩
那俄铍矿
梁河县
滇西
pegmatite vein type beryllium deposit
petrogeochemistry
U-Pb geochronology
Early Cretaceous granite
Na’e beryllium deposit
Lianghe County
western Yunnan Province
