赣南隆坪萤石矿床成矿时代及成因初探：来自萤石Sm-Nd测年及黑云母电子探针的证据

隆坪萤石矿床是赣南已探明的大型单一萤石矿床，矿体产于永丰复式岩体外接触带北东向硅化破碎带中。文章首次 采用Sm-Nd等时线法对隆坪萤石矿进行测年和稀土元素分析，并对永丰复式岩体中黑云母矿物成分进行了系统的测试；获 得了隆坪萤石矿的成矿年龄为158±3 Ma，与永丰复式岩体的成岩时代基本一致，表明该矿床萤石成矿作用与晚侏罗世岩浆 活动关系密切。隆坪萤石矿中萤石轻稀土元素略富集，重稀土相对平坦，具微弱Ce正异常（δCe=1.08~1.11，平均1.09） 和 微弱Eu负异常（δEu=0.91~0.98，平均0.95），指示了萤石矿床的成矿流体经历了相对较高的温度。黑云母电子探针分析结 果证实永丰复式岩体形成于相对高温、低压和高氧逸度的环境，岩浆起源于古老地壳物质的部分熔融，岩浆结晶分异晚阶 段岩浆期后热液富含F等挥发分。隆坪萤石矿床形成于晚侏罗世，成因类型为岩浆期后热液充填型。

A Preliminary Study on Metallogenic Age and Genesis of Longping Fluorite Deposit in Southern Jiangxi Province: Evidence from Sm-Nd Isochron Dating of Fluorite and Electron Probe of Biotite

The Longping fluorite deposit is the large single fluorite deposit discovered in southern Jiangxi Province, China. The ore body occurs in the NE-trending silicified fractured zone within the outer contact zone of the Yongfeng complex. In this paper, for the first time, the Sm-Nd Isochronal method is used to estimate the age of Longping fluorite deposit, and rare earth elements and the mineral composition of biotite in the Yongfeng complex are systematically studied. The ore-forming age of the Longping fluorite deposit is 158 ± 3Ma, which is consistent with the diagenetic age of the Yongfeng complex, indicating that the Yanshanian fluorite mineralization in this area was closely related to the Late Jurassic magmatism. The fluorite in the Longping fluorite deposit is enriched in light rare earth elements, and the heavy rare earth elements remain relatively unchanged, with weak Ce positive anomalies (δCe= 1.08-1.11, average 1.09) and weak Eu negative anomalies (δEu=0.91-0.98, average 0.95), indicating that the ore-forming fluids of the fluorite deposit experienced relatively high temperature. The results of electron probe analysis of biotite show that the Yongfeng complex was formed in a relatively high temperature, low pressure, and high oxygen fugacity environment. The magma originated from the ancient crustal materials and the hydrothermal fluid was rich in F and other volatiles after the magma phase. The Longping fluorite deposit may have mineralized in the Late Jurassic, and the genetic type is hydrothermal filling after the magmatism