鲁西碱性岩——碳酸岩型稀土矿稀土元素赋存状态及矿床成因

Occurrence and Origin of Rare Earth Elements in Alkalicarbonate Rock Type Rare Earth Deposits in Western Shandong Province

摘要:

鲁西微山—淄博地区是我国重要的碱性岩碳酸岩型稀土矿产成矿带和找矿有利区，已发现稀土矿床（点）9处，具有很好的找矿潜力。但是关于矿床中稀土矿物的微观矿物学特征尤其是稀土元素赋存状态研究工作鲜有报道。本次通过开展稀土元素赋存状态和规律研究，认为郗山稀土矿在岩浆演化晚期阶段形成少量独立矿物氟碳铈矿和氟碳钙铈矿，并伴随着天青石等矿物生成；大量的稀土矿物氟碳铈矿和氟碳钙铈矿在岩浆期后热液活动阶段形成。从矿床时空分布、构造和岩浆岩等3个方面分析了鲁西地区稀土矿（点）控矿因素，建立了鲁西碱性岩碳酸岩型稀土矿床“岩石圈上涌导致富稀土的碳酸盐化地幔部分熔融＋岩浆热液继承性成矿”的成矿模型。

Abstract:

WeishanZibo area in western Shandong province is an important metallogenic belt and favorable prospecting area of alkalicarbonate rare earth deposits in China. Nine rare earth deposits (spots) have been discovered with good prospecting potential. However, there are few reports on the microscopic mineralogical characteristics of rare earth minerals in the deposit, especially on the occurrence of rare earth elements. In this study, the occurrence and regularity of rare earth elements have been studied by electron probe. It is considered that a small number of independent minerals, such as bastnaesite and bastnaesite were formed in the late stage of magmatic evolution, accompanied by celestite and other minerals. A large number of rare earth minerals, such as bastnaesite and bastnaesite were formed in hydrothermal activity stage after magmatic period. From the aspects of temporal and spatial distribution, structure and magmatic rocks, the orecontrolling factors of rare earth deposits (spots) in western Shandong province have been analyzed, and a metallogenic model of alkaline rockcarbonate rare earth deposits has been established, including partial melting of carbonate rock mantle induced by upwelling of the lithosphere and the inheritance of magmatic hydrothermal mineralization.