摘要
为了查明南秦岭镇安西部大型钨钼多金属矿集区成矿物质来源,在矿床基础地质研究的基础上,运用岩石地球化学、硫化物单矿物硫同位素地球化学和锆石U-Pb同位素、辉钼矿Re-Os同位素地球化学等方法,对复式中酸性侵入体与钨钼成矿的时空关系和成因联系进行深入研究。结果表明:懒板凳岩体田湾单元、王家坪隐伏岩体和花岗细晶岩脉富集Si元素,且Mg#值和稀土总量较低,稀土元素配分曲线呈明显的四分组效应并具有强负Eu异常,岩浆分异结晶程度高;懒板凳岩体九间屋单元和王家坪隐伏岩体锆石U-Pb同位素年龄分别为(222.7±2.6)Ma和(201.6±4.7)Ma,棋盘沟钨矿床和江口钼矿床中辉钼矿Re-Os同位素模式年龄分别为(199.7±3.9)Ma和(198.7±3.9)Ma;钨钼矿床中硫化物单矿物δ34S值为3.6‰~10.2‰,推测成矿物质来源于复式岩体晚阶段形成于190~200Ma之间的高分异演化酸性侵入体。
The large tungsten-molybdenum polymetallic ore concentration area in the western of Zhen’an,Shaanxi Province is located in the north of the southern Qinling tectonic belt,where faults,joints and complex intermediate-acid intrusions are closely related to skarn type and quartz vein type tungsten-molybdenum mineralization.Although certain exploration and research achievements have been made in the study area,it is still unclear which period of magmatic activity in the complex massif is related to mineralization.That is,the source of ore-forming materials is still unclear,which restricts the further exploration and prospecting.On the basis of the basic geological study of the deposit,related magmatic rock samples were collected for geochemical testing and zircon U-Pb isotope dating,sulfide mineral for sulfur isotope analysis,and molybdenite for Re-Os isotope dating.Based on the spatio-temporal relationship between complex massif and tungsten-molybdenum mineralization,it is considered that the Tianwan unit of Lanbandeng rock mass,Wangjiaping concealed rock mass and granitic fine-grained dike are rich in SiO2,and the Mg#and the total REE content are low.The REE distribution curve shows obvious tetrad effect with strong negative Eu anomaly,and the magmatic differentiation crystallization degree is high.Zircon U-Pb isotope ages of Jiujianwu unit of Lanbandeng rock mass and Wangjiaping concealed rock mass are(222.7±2.6)Ma and(201.6±4.7)Ma,respectively.The Re-Os isotope model ages of molybdenite in Qipangou tungsten deposit and Jiangkou molybdenum deposit are(199.7±3.9)Ma and(198.7±3.9)Ma,respectively.The sulfide mineralδ34S of tungstan-molybdenum deposit ranges from 3.6‰to 10.2‰.The source of ore-forming materials should be the acid intrusion formed in late stage between 190 Ma and 200 Ma,which is represented by Tianwan unit of Lanbandeng rock mass,Wangjiaping concealed rock mass and granitic dike.
作者
韩珂
杨兴科
HAN Ke;YANG Xingke(CCTEG Xi’an Research Institute(Group)Co.,Ltd.,Xi’an 710077,Shaanxi,China;School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,Shaanxi,China)
出处
《黄金科学技术》
CSCD
北大核心
2024年第1期13-30,共18页
Gold Science and Technology
基金
陕西省地勘基金成果集成项目“陕西秦岭成矿带金矿成矿规律与找矿预测”(编号:61201506280)资助。
关键词
钨钼矿集区
成矿物质来源
复式岩体
镇安西部
南秦岭
tungsten-molybdenum ore concentration area
ore-forming material source
complex rock mass
western area of Zhen’an
southern Qinling
