Abstract: The geological characteristics and mineralization of the endogenetic rare earth elements (REE) deposits related with carbonatite-alkaline complexes are reviewed. The REE deposits mainly include primary magmatic and hydrothermal types. The former is relatively rare, and REE minerals crystallized from carbonatite magma. The REE minerals in hydrothermal deposits are intergrowth with calcite, fluorite, barite, quartz. They occur as ore veins intruding carbonatite-alkaline complexes and wall rocks, or as fracture or void filling fine-grained, polycrystalline aggregates overprinting earlier carbonatitic minerals. Previous researches showed that REE mineralization was controlled by the crystallization and accumulation of carbonate minerals during carbonatitc magma-hydrothermal processes. However, REE enrichment mechanism is still debate, i.e. liquid immiscibility of carbonate-silicate magmas, fractional crystallization of carbonate minerals from carbonatite magma, extraction of carbonatitic liquids, and hydrothermal alteration of carbonatites. Note carbonatites normally show light REE enrichment and mineralization, and absent heavy REE minerals. Therefore, high temperature and pressure experiments on REE partition coefficients between volatile-rich carbonate and alkaline silicate melts or fluids, and REE partition behavior between carbonate and co-precipitating minerals during carbonatite magma evolution, will be a key to reveal the REE mineralization mechanism.

Key words: carbonatite-alkaline complex, endogenetic REE deposits, REE enrichment mechanism, immiscibility, fractional crystallization, hydrothermal alteration

摘要： 综述与碳酸岩?碱性杂岩体相关的内生稀土矿床的基本特征和成矿作用研究进展。根据矿化特征, 该类矿床大体可以分为原生岩浆型和热液型, 前者稀土矿物是从碳酸岩岩浆中直接结晶出来, 矿化主要产于碳酸岩岩体中; 后者稀土矿物通常与方解石、萤石、重晶石、石英等矿物共生形成脉体, 穿插于碳酸岩杂岩体及围岩中, 或作为裂隙或空洞充填物, 或呈细粒多晶集合体叠加在碳酸岩中早期形成的矿物之上。以往的研究对于稀土富集成矿的主要机制是碳酸岩和硅酸岩岩浆的液态不混溶作用或碳酸岩岩浆中碳酸盐矿物的分离结晶作用, 还是岩浆期后热液蚀变或不混溶的碳酸岩质流体的萃取作用, 存在很大的争议; 同时，与稀土成矿相关的碳酸盐体系选择性地富集轻稀土, 该类矿床中很少见到重稀土矿物, 亦是有待解决的问题。因此, 加强稀土元素在富挥发份的碳酸岩熔体和碱性硅酸岩熔体或流体之间, 以及碳酸盐矿物及共沉淀相与碳酸岩熔体之间分配行为的高温高压实验研究, 将是揭示该类稀土矿床成因的关键。

关键词: 碳酸岩-碱性杂岩体, 内生稀土矿床, 稀土富集机制, 不混溶, 分离结晶, 热液蚀变