Ore and skarn mineralogy of the Yamato mine, Yamaguchi Prefecture, Japan with emphasis on silver-, bismuth-, cobalt-, and tin-bearing sulfides.
Ore and skarn mineralogy of the Yamato mine, Yamaguchi Prefecture, Japan with emphasis on silver-, bismuth-, cobalt-, and tin-bearing sulfides.
复制标题
日本山口县大和矿的矿石和矽卡岩矿物学，重点研究含银、铋、钴和锡的硫化物。
作者：
Nagashima;M.;Akasaka;M.;and Morifuku;Y.
通过对日本山口县大和矿区矿石矿物组合和化学成分的详细研究，阐明了该矿床的夕卡岩型存款特征。特别关注的是该矿的含银、铋、钴和锡的硫化物矿物和自然金，这是本文首次描述。从矿山垃圾场收集了毒砂占主导地位的块状矿石、富石榴石、富单斜辉石石榴石和含硅灰石的夕卡岩矿石样品。毒砂是最丰富的矿石矿物（>80体积%）在块状矿石中，与贫As/游离和含As黄铁矿有关。矽卡岩标本中的主要矿石矿物为黄铁矿、磁黄铁矿、毒砂、黄铜矿、方铅矿和闪锌矿，沿着少量辉银矿、银铅铋硫酸盐、辉铋矿、自然铋、辉铋矿、白钨矿、锡铁矿、类锡铁矿、砷铜矿、钴矿、辉砷铋矿和富钴紫砷铜矿。此外，在脉石矿物的空隙中还观察到自然金。根据矿物组合和结构特征，主要矿石矿物形成于成矿早期，Bi、Ag、Co、Ni、As、Sn等成矿作用发生于成矿中期。自然金为晚期沉积。根据铁、锌在锡矿和闪锌矿之间的分配关系，估计成矿中期的形成温度为312±5 °C。大和矿的矿物学性质和成矿过程与山阳和山阴地区与钛铁矿系列花岗岩有关的常见矽卡岩和脉型矿床的矿物学性质和成矿过程一致。
Assemblages and chemical compositions of ore minerals from the Yamato mine, Yamaguchi Prefecture, Japan, were investigated in detail to clarify its characteristics as a skarn deposit. Special attention was paid to silver‐, bismuth‐, cobalt‐, and tin‐bearing sulfide minerals and native gold at the mine, which are described here for the first time. Samples of arsenopyrite‐dominant massive ore, and garnet‐rich, clinopyroxene‐garnet‐rich, and wollastonite‐bearing skarn ores were collected from the mine dump. Arsenopyrite is the most abundant ore mineral (>80 vol.%) in the massive ore, in association with both As‐poor/free and As‐bearing pyrite. The major ore minerals in the skarn specimens are pyrite, pyrrhotite, arsenopyrite, chalcopyrite, galena, and sphalerite, along with minor argentite, Ag‐Pb‐Bi sulfate, matildite, bismuthinite, native bismuth, molybdenite, scheelite, stannite, stannoidite, cassiterite, cobaltite, gersdorffite, and Co‐rich violarite. In addition, native gold is observed in the interstices of gangue minerals. Based on the mineral assemblages and textures of the specimens examined, the major ore minerals formed in the early stage of mineralization, and the Bi‐, Ag‐, Co‐, Ni‐, As‐ and Sn‐mineralization occurred in the middle stage. Native gold was deposited in the late stage. The estimated formation temperature of the middle mineralization stage was 312±5 °C, according to iron and zinc partitioning between stannite and coexisting sphalerite. The mineralogical properties and mineralization process of the Yamato mine are consistent with those of common skarn‐ and vein‐type ore deposits associated with ilmenite‐series granitoids in the San‐yo and San‐in districts.