Characteristies and time-spatial analysis of epitharmal Au-Ag mineralization and acid-sulfate alteratin

对岛弧地质环境中与年轻火山活动有关的浅成热液金银矿床的成因和形成过程进行了研究，在野外和实验室工作的基础上，从矿石地质学、地球化学和岩石学的角度阐明了金银矿床的形成环境和元素的聚集过程。为了提高和提高化学分析的准确性，还进行了基础实验。研究了表热和中热条件下低硫化和高硫化两种金矿化类型的矿石和蚀变矿物组合，确定了这两种类型的物理化学条件和时空关系。并将研究领域扩展到日本东北部和印度尼西亚的同类地区进行对比研究。作为结束语，阐明了高硫化型金矿化受岩浆流体的强烈影响，而低硫化金矿化受大气降水的影响。前者先于后者，位置更靠近侵入岩。这两种类型的金矿化都与岩浆活动密切相关，起源的高温流体以硫化物络合物的形式溶解各种金属，可能是由于降压沸腾和/或与大气水混合而在浅层环境中导致冷却、氧化或稀释而有效地沉淀了它们。

On the genesis and formation process of the epithermal Au-Ag deposits related to young volcanic activities in the island arc geologic environ- ment, it is investigated to clarify the formation environment and con- centration process of the elements from the viewpoints of ore geology, geochemistry and petrology based on the field and laboratory works. Basic experiments are also conducted in order to improve and obtain high accuracy in chemical analyses.Both low- and high-sulfidation types of gold mineralizations in epi- and meso-thermal conditions are investigated on their assemblages of ore and alteration minerals to determine the physicochemical conditions and time-spatial relationships of the both types. Study fields are also extended to the same types in northeast Japan and Indonesia to make comparative study.As a concluding remarks, it is clarified that the high-sulfidation type gold mineralization is stongly affected by the magmatic fluids, but the low-sulfidations is by meteoric water. The former is prior to the latter and is located closer to the intrusive rock. Both types of gold mineralizations are strongly related to the magmatic acitivity, and the originated high temperature fluids dissolving various metals in the style of sulfide complexes might have effectively precipitated them due to the boiling by pressure decrease and/or mixing with meteoric water to cause cooling, oxidation or dilution in shallow environment.