南岭萤石矿床成矿规律及成因

Metallogenic regularities and genesis of the fluorite deposits in Nanling region

南岭成矿带是我国最重要的萤石矿聚集区之一。本文从矿床类型、空间分布格局、成岩成矿时代、稀土元素组成、成矿流体特征、成矿物质来源、矿床成因等方面对区内萤石矿床进行了研究与总结。南岭萤石矿床的数量东多西少,储量则是"中间大,两头小",矿床类型中亚带以伴生型为主,东亚带和西亚带主要为单一型。成矿时限介于160~100 Ma之间,集中在160~135 Ma,由中亚带向西亚带和向东亚带有变年轻的趋势。单一萤石矿床以大气降水为主的成矿热液沿破碎带循环、淋滤,使花岗岩中的F以及地层中的Ca再次活化、富集、重结晶成矿,成矿相对于成岩具有较为明显的滞后性,时差为10~20 Ma。伴生型萤石矿床首先经历岩浆-热液-成矿作用,由花岗岩浆的F与地层的Ca结合形成,成岩与成矿作用近于同步,后期又经历了大气降水改造和重结晶。

Nanling region is one of the most important fluorite ore-concentrated rich areas in China.In this study,mineralization styles,spatial distribution,geochronology,rare earth element composition,ore-forming fluids and genesis of fluorite deposits in this region are systematically investigated.Fluorite deposits decrease in number from the eastern to the western subzone,and most of the reserves are concentrated in the middle subzone.The middle subzonemainly hosts the associated type mineralization,while the single type fluorite deposits are commonly found in the eastern and western subzones.Their ages range between 160~100 Ma with a peak between 160 Ma to 135 Ma.Deposits in middle subzone are older than that those inthe eastern and western subzones.The single type fluorite deposits have significant time lag between mineralization and its associated granite emplacement(10~20 Ma).They are considered to have crystallized from meteoric waters which constantly leached and enriched fluorine from granite and calcium from strata.The associated type fluorite deposits were primarily produced by magmatic hydrothermal activity.