华北板块北缘东段稀有-稀土成矿作用综述

    RARE METAL AND RARE EARTH ELEMENT MINERALIZATION IN THE EASTERN SECTION OF THE NORTH MARGIN OF NORTH CHINA PLATE: A Review

    • 摘要: 华北克拉通北缘东段稀有-稀土矿产资源主要分布在板块边缘或不同时代的构造接合处, 受郯庐断裂带、索伦-西拉木伦-长春-延吉断裂带等区域性大断裂控制, 主要经历了吕梁期、印支期和燕山期等3期的构造-岩浆事件. 区内的稀有-稀土矿产与中元古代和中生代岩浆岩关系密切. 目前, 研究区内已发现稀有-稀土矿床或矿点10余处, 主要分布于辽宁省和内蒙古东部地区, 成矿类型以碱性花岗岩-碱性岩型为主, 伟晶岩型次之. 区内稀有-稀土成矿均与碱性岩浆作用有关, 成矿岩体的年代学研究表明, 成矿作用可分为3个阶段, 即燕山期的120~140 Ma、印支期的200~230 Ma以及与吕梁运动有关的2 500~2 510 Ma. 本区稀有-稀土元素富集成矿过程主要与碱性岩浆的高度演化密切相关, 在水和挥发分作用下, 岩浆强烈分异结晶, 导致成矿元素迁移聚集, 随着温度、压力等成矿条件的变化, 含矿流体在岩浆作用晚期随着主要造岩矿物的晶出而富集成矿.

       

      Abstract: The rare metal and rare earth mineral resources in the eastern section of the north margin of North China Plate are distributed mainly in the plate margin or tectonic junction of different ages, controlled by regional major faults, such as Tancheng-Lujiang fault belt and Suolun-Xilamulun-Changchun-Yanji fault zone, and experienced mainly three stages of tectono-magmatic events including Lyuliangian, Indosinian and Yanshanian. The rare metal-rare earth minerals in the area are closely related to Mesoproterozoic and Mesozoic magmatic rocks. Over 10 rare metal-rare earth deposits or ore occurrences have been found so far, distributed mainly in Liaoning Province and eastern Inner Mongolia, dominated by metallogenesis of alkaline granite-alkali rock type, followed by pegmatite type. The mineralization of rare metal-rare earth elements is related to alkaline magmatism. The geochronology of ore-forming rock mass shows that the mineralization can be divided into three stages: Yanshanian (120-140 Ma), Indosinian (200-230 Ma) and Lyuliangian(2500-2510 Ma). The enrichment and mineralization process of rare metal-rare earth elements is closely related to the advanced evolution of alkaline magma. Under the action of water and volatiles, the magma experienced strong fractional crystallization, resulting in migration and accumulation of ore-forming elements. With the change of mineralization conditions such as temperature and pressure, the ore-bearing fluids were concentrated and mineralized in the late stage of magmatism with the crystallization of major rock-forming minerals.

       

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