明延鉱山の帯状分布について

抄録

The ore deposits of Akenobe Mine is subvolcanic hydrothermal copper-lead-zinc-tin-tungsten quartz vein. The ores consist mainly of chalcopyrite, sphalerite, cassiterite, galena, bornite, wolframite, scheelite, arsenopyrite, magnetite, and subordinate amount of pyrrhotite, pyrite, bismuthinite, native bismuth, molybdenite, etc. The ores are associated with quartz, chalcedonic quartz, fluorite, calcite, siderite, chlorite, apatite, manganiferous calcite, and clay. minerals.
The geology of this district is composed of mainly Paleozoic sedimentary formations, gabbroic intrusive rocks, granophyric rock and many kinds of dike rocks.
For the purpose of zonal distribution investigation. the writer was availed to great number of chemical analyses of ores and geologic data. From the results of observations based on these data, understood remarkable arrangement of ores within vein groups, are as follow :
(1) The zoning at Akenobe is showing on both horizontal and vertical.
(2) Five zones are recognized, SnW-CuSn-CuZn-PbZn-AuAg, which are consist of from central to peripheral zone.
(3) The zonal arrangement is controlled by many factors, such as pre-ore NE faults, interstructure of vein flssures, erosion of surface, post-ore movement, difference in country rocks, and repeating of mineralizations, gradient of temperature and pressure, etc.
(4) The most important factor in the localization of zoning is pre-ore NE faults. Those are lie along the gabbroic intrusions.
The writer conculudes that main paths of mineralizing solutions are the NE pre-ore fanlts and mineralized solution had ascend through its faults. Therefore characteristic zonal distribution was formed.
These geological features are important in prosecting.