浙西北岩前高氟岩体地球化学特征及其与新类型萤石矿床成矿关系

浙江八面山特大型萤石矿田属新类型矿床。矿体特征研究表明，其赋存形式及矿石特征与一般萤石矿床不同，具独特性。本文通过岩石学及地球化学特征表明，浙西北岩前岩体富含挥发分，属高氟高硅、贫钙低钛低磷、钙碱性、准铝质一弱过铝质（铝饱和指数ASI：0．96～1．17）岩石。岩浆来源较复杂，既有壳源，也有壳幔混合源，岩浆分异作用强烈。稀土元素分析结果表明，岩体稀土元素含量较高，轻重稀土比值较小（2．24—3．52），Eu亏损明显（8Eu=0．01—0．03），轻重稀土分馏较弱。研究还表明，岩前岩体并非过去认为的S型花岗岩，而具有A型花岗岩的特征。矿田萤石矿体与岩前岩体在空间、时间上关系密切，岩体不仅为萤石成矿提供了氟源，侵位形成的构造还为新类型萤石矿提供了赋矿空间。

Geochemical Characteristics of the Yanqian High-F Granite and Its Relationship with the New-Type Bamianshan Fluorite Deposit in Northwest Zhejiang Province

The Bamianshan super-large fluorite deposit in Zhejiang Province is a new-type fluorite deposit.which exhibits unique occurrences and ore characteristics obtained from its orebody investigation.Petrological and geochemical studies undertaken in this study reveal that the Yanqian granite is rich in volatile components,with high-F and SiO2,and low CaO,TiO2 and P2O5.The granite belongs to calci-alkalic and para-aluminous-week peraluminous rock (ASI=0.96~1.17).The magma origination is complicated by a mixture of crustal and crust-mantle sources.The magma differentiation is strong.The granite is also rich in REE,with lower LREE/HREE values (2.24~3.52),and displays obviously negative Eu (δEu=0.01~0.03).The LREE and HREE differentiation is week.And the granite is not the previously determined S-type,but A-type.The Bamianshan fluorite orebodies in the ore field are located close to the Yanqian granite spatially and temporally.The granite not only offers ore-forming element F for the Bamianshan ore field,but also provides space for ore precipitation after the magma invaded.