摘要
洞子沟银矿床是新近发现的产于中元古代裂谷的银多金属矿床 ,矿床地质特征和成因在过去的研究中作过报道 ,但对其成矿时代不十分清楚。本文通过对洞子沟银多金属矿床中切割矿体的辉绿岩脉进行Sm Nd同位素年龄的测定 ,结合矿床地质特征的研究和Pb同位素的分析 ,认为洞子沟银多金属矿床和中元古代团山子期 -大红峪期火山喷发作用有关 ,其成矿年龄应为 1683～ 152 1Ma ,属中元古代。
s: Dongzigou(洞子沟) silver-polymetal deposit is new type silver deposit in North China Craton. The minerogentic background and geological characteristics reported in the past, it is suggested that the is volcanogene hydrothermal one related middle Proterozoic (1 683～1 625 Ma) volcanic action. The mineralitic age is not very clear because the direct timing technique is not available for most ore. Fortunately, a basic dyke intruding into the ore body has been discovered in Bianqianggou(边墙沟), south of Dongzigou(洞子沟) miner field. The isotopic composition of six whole rock samples from the basic dyke can yield two comparative precise lines respectively, the first Sm Nd isochron age is (1 521±4)Ma with INd =0.511 017,εNd(t)=+6.8,the second one is 1 521 Ma with INd =0.510 825,εNd(t)=+3.0. The likely explanation of these ages is that the basic dyke is intruded into the ore body at～1 521 Ma, and the mineralitic age should be older than 1 521 Ma. The lead isotopic age also take out about 1 600～1 700 Ma data. Based on these studies, it can be deduced that the mineralitic age is between 1 683 Ma to 1 521 Ma.
出处
《前寒武纪研究进展》
2001年第1期58-63,共6页
Progress in Precambrian Research
基金
原地矿部资源与环境"九五"攻关项目! (No .950 2 0 0 3)
