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鲕状黄铁矿是都龙锡锌多金属矿床中的特殊硫化物矿物之一。本文通过扫描电镜观测其矿物微形貌结构特征,并利用电子探针分析其化学成分,为认识该类矿物成因及其与成矿作用的关系提供依据。扫描电镜观测显示,该矿床中黄铁矿鲕粒主要由黄铁矿微晶组成,在鲕粒纹层孔隙中发现了丝状体、杆状体、球状体等微生物成因显微组构。这些微生物化石与热液喷流沉积成因硫化物矿床、热泉、海底热液喷口中的微生物化石具有诸多相似特征,表明该矿床形成过程中可能存在热水沉积成矿作用,微生物在黄铁矿鲕粒形成过程中可能起到转换硫源、吸附金属元素、粘结黄铁矿微晶等作用。电子探针观测显示,黄铁矿鲕粒中的Zn含量较高,暗示鲕状黄铁矿可能作为后期成矿作用Fe、Zn、S等成矿元素的物源之一。从鲕粒边部到中心Zn含量逐渐递减的趋势,并由交代作用在鲕粒边部形成富Zn边。
Oolite pyrite is one of the special sulphide minerals in the Du Long tin zinc polymetallic deposit. In this paper, the microscopic morphological features of minerals are observed by scanning electron microscopy. The chemical composition of the minerals is analyzed by electron probe, which provides the basis for understanding the genesis of this mineral and its relationship with mineralization. Scanning electron microscopy observations showed that the oolites of pyrite in this deposit are mainly composed of pyrite microcrystals. Microfacies of filaments, rods, spheroids and other microorganisms were found in the pores of oolitic patterns. These microbial fossils have many similarities with hydrothermal jet deposits due to the formation of sulfide deposits, hot springs and microbial fossils in the seabed hydrothermal vents, indicating that there may be hydrothermal sedimentary mineralization during the formation of the deposit. Ooids may play a role in conversion of sulfur sources, adsorption of metal elements, bonding pyrite microcrystal and so on. Electron probe observations showed that the Zn content of pyrite oolites was high, suggesting that oolitic pyrite may be one of the sources of metallogenic elements such as Fe, Zn, S and so on. From the edge of the oolitic edge to the center of the Zn content gradually decreasing trend, and by the account of the role of the edge of the oolitic edge to form a rich Zn.