庐枞盆地酸性蚀变岩帽中铝-磷酸盐-硫酸盐矿物（APS）成因机制研究

与斑岩-浅成低温热液矿床有关的酸性蚀变岩帽具有重要的勘探和理论意义，明矾石超族是其代表矿物，钾钠明矾石已有详细研究，但反映物理化学特征的铝-磷酸盐-硫酸盐矿物即APS研究甚少。APS是交代磷灰石或直接从热液流体中沉淀的成因尚有争议，钾钠明矾石中代表低温的Pb在APS中却表明高温环境。尚不清楚的APS成因机制和元素意义制约了对酸性蚀变岩帽形成条件的深入认识和寻找新的勘探指标。庐枞盆地是长江中下游成矿带重要矿集区，发育大范围酸性蚀变岩帽，形成的APS因其稳定结构和特殊化学性质，是限定成矿条件的优良指示矿物。选择盆地内矾山、钱铺、笔架山APS为主要研究对象，开展矿物学、原位化学和同位素等研究，探讨APS元素关系，确定酸性蚀变岩帽形成条件；阐明APS形成机制，分析其与钾钠明矾石和磷灰石之间的共生关系，确定成因联系。研究结果将深化对APS及酸性蚀变岩帽形成过程的理论认识，推动酸性蚀变岩帽的找矿指示。

Recently the lithocap associated with porphyry-epithermal system have attracted wide attention and have important exploration and theoretical significance. Alunite supergroup are its representative minerals, K - and Na - alunite have been detailed studied, but aluminum phosphate - sulfate minerals (APS) belonging to alunite supergroup, which can reflect the physical and chemical characteristics, are rarely studied. It is not clear that APS minerals replaced apatite or deposited directly from hydrothermal fluids. And Pb element in the K- and Na-alunite formed in the low temperature, while in the APS it indicates the high temperature environment. Therefore, the unknown genetic mechanism of APS and the significance of elements restrict the further understanding of the formation conditions and the search for new chemical exploration indicators in lithocap. The Luzong Basin is an important ore concentration area in the middle and lower reaches of the Yangtze River, where a wide range of lithocaps and alunite deposits are developed. Due to its stable structure and special geochemistry, the magmatic hydrothermal APS is an excellent indicator mineral to limit the ore-forming conditions. This project chooses APS from Fanshan, Qianpu and Bijiashan areas in the Luzong Basin as the study mineral, through mineralogy, in-situ major and trace elements, and in-situ isotopes of APS to discuss the relationship of elements in APS and then determine different physical and chemical conditions of lithocap, to elucidate the formation mechanism of APS and deeply analyze the intergrowth relationship between APS and K -, Na - alunite and apatite, and clarify their genetic relationship. The above research results will deepen the theoretical understanding of APS and the formation process of lithocap and promote the indication of lithocap and epithermal deposits for ore prospecting.