摘要
大场金矿位于北巴颜喀拉造山带中段,其成矿作用与热液活动有密切关系。大场金矿含金石英脉中的锆石可分为岩浆锆石和热液锆石2大类。准确的区别出不同成因的锆石对进一步准确确定该矿床的成矿年龄的研究具有重要的意义。通过在扫描电镜下2类锆石的阴极发光图像特征对比以及锆石微区测试的微量元素特征进行对比,在阴极发光图像下热液锆石形态呈局部溶蚀状,无环带或弱环带,呈半透明到不透明;岩浆锆石阴极发光显示较强的发光性和清晰的环带,阴极发光图像为灰色、灰黑色。岩浆锆石的稀土表现为轻稀土亏损,重稀土强烈富集型。稀土配分曲线为左倾式,具有较高的Ce正异常和适度的Eu负异常。热液锆石相对岩浆锆石富集轻稀土,其稀土配分模式比较平坦,轻重稀土分异强度较岩浆锆石弱。Th/U比值以及Th和U含量明显高且变化范围很大。具有弱的Ce正异常,适度Eu负异常。
Dachang Gold Deposit is located in the North Bayanhar acrogenic belt.The mineralization is closely related to hydrothermal activity.In the Dachang Gold Deposit,there are magmatic zircon and hydrothermal zircon in the goldbearing quartz vein.To accurately distinguish the different causes of zircon has great significance to determine the age of deposit.By the scanning electron microscope,and compared with the feature of the cathodoluminescence image and zircon trace element characteristics of two types of zircons,the cathodoluminescence images show that morphology of the hydrothermal zircon is partial dissolution,a ring or weak ring structure and translucent to opaque.Cathodoluminescence image of magmatic zircon shows strong luminescence and clarity ring structure,the color is gray or black.Zircon rare earth elements of magmatic zircon manifeste the loss of light rare earth elements,and strongly enriche in heavy rare earth type.Rare earth element patterns are left-leaning style,with a high positive Ce anomalies and moderate negative Eu anomalies.While hydrothermal zircon relative to magmatic zircon enriches in light rare earth elements,their rare earth element patterns are more flat heavy rare earth elements fractionation than magmatic zircons from the weak intensity.Th/U ratios and Th and U were significantly higher and vary widely,and has weak positive Ce anomalies,moderate negative Eu anomalies
出处
《长江大学学报（自科版）（上旬）》
CAS
2012年第7期38-40,6,共3页
JOURNAL OF YANGTZE UNIVERSITY (NATURAL SCIENCE EDITION) SCI ＆ ENG
关键词
大场金矿
热液锆石
岩浆锆石特征
Dachang Gold Deposit
hydrothermal zircon
magmatic zircon
