LIN Fang-mei1, PENG Jian-tang1, 2, HU A-xiang1, DENG Mu-kun1
(1. Key Laboratory of Non-ferrous Metals Metallogenic Prediction of the Ministry of Education, School of Geosciences and Info-physics, Central South University, Changsha 410083, China;
2. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China)
Abstract: Xikuangshan antimony deposit, located in central Hunan Province, China, is the largest antimony deposit in the world. Many studies have been done on this deposit but there still exist many different opinions on its ore genesis and the metallogenic mechanisms involved. Fluorite from the Xikuangshan deposit has received little attention during the past several decades. Geological characteristics of fluorite from this deposit are described in this paper. As well, a REE geochemistry study was carried out on fluorite samples collected from the deposit. It is revealed in this study that fluorite usually contains higher REE concentrations (100.09×10-6～139.38×10-6). Furthermore, its normalized REE pattern is characterized by obvious LREE-depletion, MREE and HREE enrichment, and a weak negative Eu anomaly. MREE3+ and HREE3+ substituting Ca2+ into fluorite are mainly controlled by their ionic radius. Behaviour of REE distribution between fluorite and hydrothermal fluids has little relationship with the stabilities of REE complexes in the ore-forming fluid. In addition, it is concluded that the fluorite formed under a reduction condition where fluorite precipitation is predominately caused by drastic variations of temperature and pressure. Ca and F in the fluorite are likely derived from limestone and deep magmatic rocks from the mining area respectively.
Keywords: fluorite; REE; ore-forming fluids; precipitation mechanism; Xikuangshan antimony deposit
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ACTA MINERALOGICA SINICA Vol. 35, No. 2, 2015, Page 214-220
