机构地区: 南京大学地球科学与工程学院地球环境计算工程研究所
出 处: 《地球化学》 1995年第C00期141-149,共9页
摘 要: 乳山金矿床位于牟平-乳山金矿带中部的昆嵛山花岗岩体内,是胶东近年来探明的一个重要石英脉型金矿床。流体包裹体地球化学研究表明,该矿床流体包裹体的气相成分以H2O、CO2为主;液相中的阳离子贫Na+、K+,富Ca2+、Mg2+,而且Na+/K+>1、(Ca2++Mg2+)>(Na++K+);成矿流体的盐度(NaCl当量)约为5%-9%,主要成矿期的温度为220-280℃,矿后期则为130-200℃。昆嵛山岩体和乳山金矿床的同位素年龄分别为134.3-124.5Ma和80±Ma,矿岩时差大(45-55Ma),氢、氧同位素研究证实,金矿床成矿热液中的水主要为大气降水,在不同的w/R值条件下。 The Rushan gold deposit, one of the important quartz-vein type gold deposits,is located in the Kunyushan granitic pluton. It lies in the central part of the Muping-Rushan gold metallogenic belt. A detailed study on fluid inclusion geochemistry indicates that the gaseous phase of the fluid inclusions is dominated by H_2O and CO_2, while the liquid phase is poor in Na+, K+, and rich in Ca(2+), Mg ̄(2+), and characterized by Na ̄+/K ̄+>1 and Ca ̄(2+)+Mg ̄(2+)>Na ̄++K ̄+. The salinity (wt.% NaCl equiv.) of the mineralizing liquid ranges from 5 to 9, the main mineralization stage has a temperature of about 220-280℃, and the late stage temperature is at about 130-200℃. The isotopic ages of the Kunyushan pluton and Rushan gold deposit are 134.3-124.5Ma and 80±Ma, respectively, indicating a great time interval between the crystallization of the pluton and the formation of the deposit (45-55Ma). The hydrogen and oxygen isotopic data show that the mineralizing solution is mainly derived from meteoric water. A genetic model is proposed to explain the metallogenetic mechanism of the gold deposit.