摘要
红岭钨矿床位于大东山‒贵东岩浆岩带的南侧,产于燕山早期热水复式岩体的中部。在红岭钨矿区出露中细粒斑状黑云母花岗岩、细粒黑云母花岗岩和中细粒白云母花岗岩。三种花岗岩SiO2含量为71.08%~75.53%,Na_(2)O+K_(2)O含量和A/CNK值分别介于7.50%~9.13%和0.97~1.42之间。其中斑状黑云母花岗岩和黑云母花岗岩属于过铝质花岗岩,而白云母花岗岩A/CNK>1.1,属于强过铝质花岗岩。锆石U-Pb年代学显示,黑云母花岗岩的年龄为161.6±1.3 Ma,白云母花岗岩的年龄为162.0±1.7 Ma,两者误差范围内一致,说明是同一岩浆活动的产物。同位素地球化学数据显示,三种花岗岩具有相似的Sr-Nd同位素组成,它们Sr同位素初始比值为0.7087~0.7214,ε_(Nd)(t)值为-15.9~-13.8,两阶段Nd模式年龄介于2065~2232 Ma之间,暗示成岩物质来自古元古代地层的重熔。元素地球化学研究显示,斑状黑云母花岗岩和黑云母花岗岩Nb/Ta值明显大于5,Zr/Hf>25,Y/Ho值<28;而晚期白云母花岗岩Nb/Ta值明显小于5,Zr/Hf<25值,Y/Ho>28。因此,红岭钨矿区三种花岗岩是同一S型花岗质岩浆不同演化阶段的产物,由早期到晚期花岗质岩浆挥发分的饱和程度逐增加,而含矿的细粒白云母花岗岩则是晚期富挥发分残余岩浆固结的产物。岩浆晚期阶段,挥发分的高度聚集可能是导致钨超常富集的关键因素。
The Hongling tungsten deposit is located in the central part of the Reshui complex,south of the Dadongshan-Guidong batholith.The granites exposed in the Hongling deposit include fine-grained biotite granite,medium-grained biotite granite,and medium-fine grained muscovite granite.The granites have geochemical features similar to those of typical tungsten-bearing granites in South China.They have SiO2 contents varying from 71.08%to 75.53%,with Na_(2)O+K_(2)O contents and A/CNK values varying from 7.50%to 9.13%and 0.97 to 1.42,respectively.The biotite granites are peraluminous,whereas the muscovite granite is strong peraluminous.Zircon U-Pb dating yielded ages of 161.6±1.3 Ma for the fine-grained biotite granite and 162.0±1.7 Ma for the muscovite granite,respectively.The granites have narrow ranges of Sr-Nd isotopic compositions,showing relatively high initial ^(87)Sr/^(86)Sr ratios(0.70^(87) to 0.7214)and negativeε_(Nd)(t)values(-15.9 to-13.8),and two-stage model ages of 2065 Ma to 2232 Ma.It is suggested that they derived from partial melting of Paleoproterozoic meta-sedimentary rocks.The whole-rock Nb/Ta and Zr/Hf ratios decrease from the biotite granites to muscovite granite,while their Y/Ho ratios increase.We argue that the overall granites in the Hongling deposit are S-type granites that experienced different degrees of fractionation.The super-enrichment of tungsten is possibly related to the concentration of volatile components in the late stage of granite evolution.
作者
吴剑
汪礼明
公凡影
叶天竺
WU Jian;WANG Liming;GONG Fanying;YE Tianzhu(CAS Key Laboratory of Minerology and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Team 932 of Geology Bureau for Nonferrous Metals of Guangdong Province,Shaoguan 512026,Guangdong,China;Geology Bureau for Nonferrous Metals of Guangdong Province,Guangzhou 510080,Guangdong,China;Development and Research Center,China Geological Survey,Beijing 100037,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2023年第3期695-710,共16页
Geotectonica et Metallogenia
基金
国家自然科学基金重点项目(41930424)资助。
关键词
红岭钨矿
S型花岗岩
Nb/Ta值
挥发分
钨富集成矿
Hongling tungsten deposit
S-type granite
Nb/Ta ratio
volatile components
tungsten-rich ore deposit
