摘要
内蒙古道伦达坝铜多金属矿床位于大兴安岭南段西坡,矿体主要产于粉砂质板岩与黑云母花岗岩的接触带。对该矿床的地层和岩浆岩进行了稀土元素和微量元素地球化学研究。结果表明:稀土元素质量分数为(18.09～532.08)×10-6,平均为235.60×10-6,磁黄铁矿的稀土元素质量分数最低,硅化砂岩最高;轻稀土元素与重稀土元素质量分数之比为7.02～12.53,平均为9.95;Eu异常为0.22～0.72,平均为0.42,呈明显的Eu负异常;Ce异常为0.97～1.07,平均为1.02,无明显Ce异常;La与Yb质量分数球粒陨石标准化后的比值w(La)N/w(Yb)N为6.57～18.72,平均为10.61,曲线呈明显右倾型;La与Sm以及Gd与Yb质量分数球粒陨石标准化后的比值w(La)N/w(Sm)N、w(Gd)N/w(Yb)N分别为2.87～4.12和1.48～2.46,轻稀土元素分异程度强于重稀土元素;重要成矿元素Sn、Cu、Ag等浓集系数很高。对矿石矿物组合进行详细观察和矿物化学研究认为:二叠系建造是该矿床主要的矿源层,其最终富集成矿与黑云母花岗岩等中酸性侵入体有成因联系;硅化砂岩有利于圈闭成矿物质,二者接触带是有利的成矿和找矿部位。
The Daolundaba copper-polymetallic deposit in Inner Mongolia is located in the west side of southern Da Hinggan Mountains.Ore bodies are mainly formed in the contact zone of silty slate and biotite granite. Geochemistry of rare earth element （REE） and trace element was studied for the formation and magmatite of deposit. The results showed that mass fraction of REE was （18.09-532.08） ×10^-6 with an average of 235.60×10^-6 ; the mass fraction of REE in pyrrhotite was lowest, and that of siliceous sandstone was highest; ratio of mass fractions of light REE （LREE） and heavy REE （HREE） was 7. 02-12. 53 with an average of 9.95; Eu anomaly was 0.22-0.72 with an average of 0.42, and was obviously negative; Ce anomaly was 0.97 1.07with an average of 1. 02, and was not obvious; ratio of mass fractions of La and Yb with chondrite standardization （w（La）N/w（Yb）N） was 6.57-18.72 with an average of 10.61, and the curve was significantly right-leaned; ratio of mass fractions of La and Sm with chondrite standardization （w（La）N/w（Sm）N） and that of Gd and Yb （w（Gd）N/w（Yb）N） were 2.87-4. 12 and 1. 48-2. 46, respectively, and the differentiation of LREE was stronger than that of HREE; concentration coefficients of important metallogenic elements including Sn, Cu and Ag were very high. The observation of ore mineral assemblage and the study on mineral chemistry suggested that Permian construction was the main source of ore in deposit, the ore concentration was genetically related to intermediate-acidic intrusion including biotite granite; siliceous sandstone was favorable to trap metallogenic material, and the contact zone was important for mineralization and prospecting.
出处
《地球科学与环境学报》
CAS
2013年第1期24-33,共10页
Journal of Earth Sciences and Environment
基金
国家自然科学基金项目(41030423
41173062
40973035)
国家重点基础研究发展计划("九七三"计划)项目(2009CB421003
2006CB403500)
高等学校学科创新引智计划项目(B07011)
关键词
铜矿床
微量元素
地球化学
成矿机制
道伦达坝
内蒙古
copper deposit
trace element
geochemistry
metallogenic mechanism
DaolundabaInner Mongolia
