浙江“常山式”萤石矿床特征及成矿模式

"常山式"萤石矿床是近年在钦杭成矿带发现并被评价的一种新类型矿床,与产于碳酸盐岩中的充填交代及层控型萤石矿床不同,其矿体赋存位置及矿石特征有其独特性。以往勘查的矿体主要分布在岩前短轴背斜的南东翼、岩前岩体与寒武系碳酸盐岩外接触带。位于背斜转折端的苦麻岭矿床的发现,丰富了"常山式"萤石矿床的成矿理论。研究表明,寒武系碳酸盐岩岩性差异与成矿关系并不密切,矿体顶底板Ca F2含量特征说明成矿作用以充填为主。燕山晚期高氟岩体侵位是矿床最重要的控制因素,岩体外接触带的"虚脱冒落"构造及层间构造带为主要控矿构造。通过矿床地质特征及成矿规律研究,总结了矿床成因,建立了成矿模式,为浙西北乃至华南地区寻找同类型矿床提供了新思路。

Geological characteristics and metallogenic model of "Changshan-type" fluorite deposits

"Changshan-type"fluorite deposits are a new type of deposits discovered in the Qinzhou-Hangzhou metallogenic belt recently. A study of orebody characteristics shows that they are different from filling-metasomatic and stratabound type fluorite deposits in carbonate rocks in location of orebody and characteristics of ores. The orebodies discovered in the past are located on the southeast limb of Yanqian brachyanticline as well as the outer contact zone of Yanqian granite and Cambrian carbonates. The discovery of the Kumalin deposit in the hinge zone of anticline enriches the metallogenic theory of the "Changshan-type" fluorite deposits. The lithologic differences of Cambrian carbonates had no obvious relationship with mineralization. Filling is the main metallogenic mode, as shown by the CaF₂ content of immediate roof and floor. Studies show that the high-F magma that invaded in the late Yanshanian epoch was the most important factor for the formation of the deposit. The roof-fall structure in the outer contact zone of Yanqian granite and interformational tectonic zone seem to be the main ore-controlling structure. Based on the study of the geological characteristics and metallogenic regularity, the authors have summarized the genesis of the deposit, established the metallogenic model and provided the new train of thought for the same type of deposits in northwest Zhejiang and even the whole South China.