摘要
江西贵溪冷水斑岩型Ag—Pb—Zn矿床产于晚侏罗世火山—侵入杂岩体中,矿化与次火山岩,主要是花岗斑岩的侵入有关.矿化和蚀变分带明显,自下而上依次出现铜矿化带、锌—铅矿化带和银矿化带以及相应的绿泥石化带,绢云母化带和碳酸盐化带.不同成矿阶段矿物的硫、碳、氧同位素组成有所不同,其变化具有较明显的规律. 矿区的铅同位素组成主要显示单阶段演化的特点,其成矿年龄约为100百万年,晚于火山—侵入杂岩体的形成(140百万年).早期矿化阶段成矿溶液的δ^(18)O_(H_2O)=9.90‰,δ^(34)S_(∑S)≈4‰,证明溶液中的水和硫主要来白岩浆,晚期成矿溶液6^(18)O_(H_2O)为4.89‰,表明大气降水逐渐增加.矿物稳定同位素组成的规律性变化表明成矿溶液是向着温度逐渐降低,氧逸度逐渐升高和pH缓慢增加的方向演化的.
Lcngshui porphyry Ag-Pb-Zn deposits occur in the laic Jurassic Lcngshui volcano-intrusive complex. The mineralization is closely associated with the subvolcanic granite porphyry of this complex. The Cu. Zn—Pb and Ag mineralization developed successively from the early to late mineralization stage. The stable isotop evidence shows that isotopic compositions vary with the Physico-chemical conditions. The lead isotopic compositions arc characterized by the monostagc evolution. The age calculated iYom the lead isotop is about 100 m.y. δ^(18) O_(H_2O) = 10.77‰andδ^(34)S_Σa≈ 4‰at the early mineralization stage. This indicates that the ore-forming materials originate mainly from the magma itself. The δ^(18)O_(H_2O)andδ^(34)S decreases wilh lower temperatures from the carly to late mineralization stage, while oxygen fugacity increases. It is evident that meteoric water in the ore—forming fluid increases gradually.
出处
《南京大学学报（自然科学版）》
CAS
CSCD
1989年第3期158-166,共9页
Journal of Nanjing University（Natural Science）
关键词
斑岩型
银铅锌矿床
稳定同位素
Porphyry Ag-Pb-Zn deposit
mineralization stage
ore-froming fluid
stable isotopic composition
physicochcmical condition
