Comparative study of mineral textures in Kuroko and Sea-floor hydrothermal ore deposit

本研究的目的是通过对矿物结构的对比研究，厘清黑子等块状硫化物矿床与海底热液矿床的成因。通过对闪锌矿矿物结构的显微观察和系统分类，重点研究了闪锌矿矿物结构与化学成分的关系及其空间分布。已经澄清了两者之间明显的亲密关系。秋田县松明矿区上部黑色矿床划分出3种类型的黑子矿，其空间分布可能受形成后成岩作用的控制。另一方面，对深泽矿金山沢东卫星矿体中的黑色矿石进行了详细的地下观测和系统取样。将矿石划分为6种类型，并明确了矿体中的分布，在不稳定斜坡上形成的黑色矿石可能被破坏或滑动，被移走再沉积。在显微镜下，基质中普遍可见玉髓石英和黄铜矿病变织构。它们可能是主成矿后热液的持续循环所致。为了与海底热液矿床进行比较，对东太平洋隆起（EPR） 13 n的样品进行了显微观察，发现两者既有相似之处，也有不同之处，这些不同之处可能与成岩作用等表观成因有关。

The purpose of this study is to clarify the genesis of massive sulfide deposits such as Kuroko and sea-floor hydrothermal ore deposits based on the comparative study of the mineral texture. Special attentions are paid for the relationships between mineral texture and chemical compositions of sphalerite and their spatial distributions according to the microscopic observation and systematic classification of mineral textures. It has been clarified the distinct intimate relationships between both. 3-types of Kuroko ore are distinguished for the Upper black ore deposits of Matsumine mine in Akita Prefecture and their spatial distributions might be controlled by the diagenetic processes after the formation. On the other hands, detailed underground observations and systematic sampling have been done for the black ore in the satellite ore body of Kanayamazawa East, Fukazawa mine. The ore is classified into 6-types and their distributions is clarified in the ore bodey, where black ore formed on the unstable slope might be distructed and/or slided to be removed and resedimentated. Matrix-filling by chalcedonic quartz and chalcopyrite diseased textures are universally observed under the microscope. They might be caused by the continued circulation of hydrothermal water after the main ore formation. To make comparison with sea-floor hydrothermal ore deposits, microscopic observations have been made for the specimen collected from East Pacfic Rise (EPR) 13ﾟ N.There are some similarities and differences between both and the latter could be depend on the epigenetic process such as diagenesis.