摘要
南楼山组火山岩为一套中酸性钙碱性岩系,属三叠世,Rb-Sr等时线年龄222±10Ma.其SiO2含量多大于57%,Al2O3多大于15%,MgO<6%,岩石富Na2O,Na2O/K2O>2者占半数,Yb为1.74μg/g,(La/Yb)N=14.2,LREE富集,δEu为0.80～0.92,弱负铕异常,Sr含量达405～1128μg/g,强烈富集,Sr/Y=44.5～48.9,SrI值为0.70533和0.7046,显示出埃达克岩的特征.官马金矿床产在南楼山火山岩系的隐爆热液角砾岩及其与围岩接触带中.火山岩浆为成矿热源和物源,属火山热液矿床.
The Late Triassic Nanloushan formation, with a Rb Sr age of 222±10 Ma, belongs to an acid intermediate volcanic rock series. The contents of SiO2 and A12O3 in most of the Nanloushan rocks are more than 57%and 15%respectively, with MgO less than 6%. The amount of the rocks that are enriched in Na2O with Na2O/K2O >2 make up half of the total. The content of Yb in the rocks is 1.74 μg/g and (La/Yb)n=14.2. The rocks are rich in LREE, with slight negative Eu anomaly (δEu 0.80 -0.92). The content of Sr is highly enriched with 405 to 1128 μg/g, Sr/Y ranging from 44.5 to 48.9, and the initial volume of Sr ( SrⅠ) 0.70746 and 0.70533 respectively.The Nanloushan volcanic rock series show the characteristics of adakite rock. The Guanma gold deposit occurs in the inner and outer contact zone of the crytoexplosive volcanic breccia and the wallrock of Nanloushan volcanic rock series. The volcanic magma of Nanloushan stage is the source of both heat and material for ore forming. The Guanma gold deposit is of the volcanogene hydrothermal type.
出处
《地质与资源》
CAS
2004年第3期137-142,共6页
Geology and Resources
基金
原地矿部科研室向基金资助.
