云南来利山锡矿床白云母标型特征研究

来利山锡矿床作为滇西地区著名的锡多金属矿床之一,为了探讨其矿床成因,为找矿勘探提供科学依据,对该矿区白云母进行标型特征研究。研究表明:白云母是该矿区的重要矿物之一,主要分布在第一、二成矿阶段及其附近围岩中;在光学显微镜下,成矿阶段白云母多呈竹叶状或扇状(放射状)集合体,围岩中白云母呈半自形—自形,解理清晰;电子探针数据显示,不同成矿阶段的白云母成分略有差异,说明其成因受到成矿热液演化影响;围岩中的白云母成分显示为多硅白云母,Na-Mg图解显示,围岩主要为中低温、中—高压环境,其中变质砂岩为高压环境,褪色角岩为高—中压环境。上述成果对于该区进一步找矿工作具有指导意义。

Study on typomorphic characteristics of muscovites in Lailishan tin deposit of Yunnan Province

Lailishan tin deposit is one of the most famous tin polymetallic deposits in western Yunnan. To investigate its ore genesis and provide scientific basis for exploration and prospecting, the authors studied typomorphic characteristics of muscovites in the mining area. The results show that muscovite is one of the most dominant minerals in this mining area, which is mainly distributed in the first and second mineralization stage and the adjacent wall rocks. The authors found that the muscovites of mineralization stages are mostly spatulate or flabellate (stellated) aggregation under optical microscope. And the muscovites of the wall rocks are mostly subhedral-euhedral and have clear cleavage. The EPMA data indicate that muscovites of different mineralization stages have different compositions, which show that the genesis of the muscovites is affected by the metallogenic hydrothermal evolution. The muscovites of the wall rocks are typically phengite. The Na-Mg diagram indicates that the wall rocks were mostly formed in medium-low temperature and medium-high pressure. The metasandstones were formed in high pressure, and the hornstones were formed in medium-high pressure. The results of this study have a guiding significance for further prospecting in this area.