GOLOGICAL CHARACTERISTICS AND GENESIS OF GLOD DEPOSIT IN THE WESTERN PART OF VOLCANIC BRECCIA AT DIANFANG

Prospecting resources to succeed in Dianfang gold deposit is focused in the western part of the volcanic breccia body and five new gold ore bodies are delineated.Morphology of the ore bodies is strictly controlled by fractures and they occur in ring and radiate fractures and the altered cataclastic rock zones.There are two types of ore,i.e.the quartz vein type gold ore and altered cataclastic rock type gold ore.Silicification and pyritization(limonitization) are the main wall rock alteration.The metallogenic process is divided into two periods and four stages.Researches on isotopes and fluid inclusions show that the ore materials are mainly derived from mantle and characterized by multi-sources and low salinity.The ore fluid is dominated by magmatic hydrothermal fluid and the ore is formed at medium and low temperatures and mainly in Late Yanshanian Period.