摘要
凡河元古宙坳拉谷关门山铅锌矿床及外围铅矿点,矿石中的铅是以正常铅为主,单阶段模式年龄为1807—1995Ma,铅质来源主要是造山带铅,铅源岩为大于2000Ma的太古宙结晶基底。矿石中异常铅具有线性关系,它是由矿石中的正常铅与放射成因铀铅组成的。结合地质观察认为1807—1995Ma是正常铅受到均一化时间,不是成矿时间。该时间大于容矿条带状白云岩的年龄1526—1600Ma。矿体受断裂构造控制,具有穿层性,矿体生成于容矿岩石成岩以后。矿床成因是属后生的。成矿时间(主矿化期)为1400—1500Ma左右,最晚矿化时间为294Ma。矿床成因属元古宙坳拉谷碳酸盐岩密西西比河谷型(MVT)后生铅锌矿床。
The lead element of the ores from Guanmenshan Pb-Zn deposits is mainly normal lead which single-stage model age is 1807-1995 Ma.The lead source was from orogenic belt.Its source rock is Archaeazoic crystall basement,>2000Ma.The anomalous lead of the ores has linear relation, which is composed of normal lead and radiogenic uranium-lead.In the light of field observation,1807-1995Ma is considered to be the time of normal lead homogenization,not of ore-forming,because the time is more earlier than the age of host rock-banded dolomite,1526-1600Ma.A orebody was controlled by fault structures and formed after the host rock diagenesis.So the oreforming age(principal mineralization age)is about 1400-1500Ma,the latest time is 294Ma.The deposit is Mississippi valley-type epigenetic Pb-Zn deposit of Proterozoic aulacogen carbonate rock.
出处
《国土资源》
1993年第1期24-37,共14页
Land & Resources
