九十三沟金矿床地质特征

THE GEOLOGICAL CHARACTERISTICS OF JIUSHISANGOU GOLD DEPOSIT

九十三沟金矿床产于延边复向斜北东端杜荒子－ 汪清中生代陆相火山断陷盆地东部的石英闪长斑岩内接触带角砾岩中，近南北向断裂构造控制金矿体的产出．成矿物质来自白垩纪浅成侵入体石英闪长斑岩，成矿热液为富含钾质的气水溶液． 矿床属岩浆期后中低温热液型金矿床．

Jiushisangou gold deposit is located in the northeast of Yanbian synclinorium—the east part of Duhuangzi Wangqing Mesozoic continental volcanic block basin Mesozoic volcanic rocks broadly spread in this area Pb isotope from quartz diorite porphyry shows that the tectonic setting of magmatism was the late period of orogenic activity (reversion orogenic belt period)in the continental margin(original arc) The content of ΣREE for the magmatic rocks is on the low side(56 86×10 6 ～118 02×10 6 ) The chondrite normalized REE patten are slightly right dipping flat curve, without europium anomaly In the illustration of (Sm/Eu) S/(Sm/Eu) N vs Sm,all kinds of rocks and ores distributed in the same level time and showed the same magmatic source derived from upper mantle Based on the relation of (Yb) N and (Ce) N and the type of REE distribution,these magma was consisted of eclogate and garnet clinopyroxenite The orebody occured in the inner and outer contact zone of quartz diorite porphyry The main orebody occured in breccia of inner contact zone Orebody was controlled by the fault nearly S N striking Potassium metasomatism is the main alteration of wallrock Orebodies occur in pyrite phyllic alteration zone Gold and polymetal sulfide fill in the fracture of pyrite phyllic altered zone and form veinlet disseminated ore Based on the research in geochemical features of S isotope and REE,we determine that metallogenic materials were derived from quartz diorite porphyry,ore forming fluid was K rich gas water solution,mineralization carried out under the condition of higher S isotopic fugacity and the temperature of 220～120℃ To sum up,Jiushisangou gold deposit belongs to post magma of low to moderate temperature hydrothermal gold deposit related to quartz diorite porphyry