| 青海赛坝沟金矿地质特征及成矿时代 |
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| 引用本文：.2002.Geological Characteristics and Oreforming Age of Saibagou Gold Deposit, Qinghai Province[J].Mineral Deposits,21(1):45~52 |
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| 基金项目:国土资源部“九五”资源与环境科技攻关项目（95-02-005） |
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| 中文摘要:青海赛坝沟金矿是近年在柴达木盆地北缘地区发现的一个较为典型的金矿床。文章对该金矿床形成的地质背景’矿床基本地质特征和成矿时代进行了研究，并对矿床成因进行了较为深入的探讨。研究结果表明，矿床主要赋矿围岩为花岗闪长岩一英云闪长岩形成时代为新元古代代表着柴北缘造山带的基底矿床严格受NW向韧-脆胜剪切带控制，与金矿化有关的蚀变主要为硅化黄铁绢英岩化和黄铁矿化，绢云母Ar- Ar法测得蚀变糜棱岩型金矿石的年龄为( 426±2)Ma，另见有含金石英脉切穿印支期花岗岩脉[全岩K-Ar年龄为(210±3)Ma]，矿化可分为两期。该矿床应为加里东期和晚华力西一印支期复合造山作用形成的造山型石英脉亚型金矿床。 |
| 中文关键词:造山型金矿 地质特征 成矿时代 青海赛坝沟 |
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| Geological Characteristics and Oreforming Age of Saibagou Gold Deposit, Qinghai Province |
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| Abstract:The Saibagou Au deposit , discovered some five years ago and located in the northwestern part of Qinghai Province , is a quite typical gold deposit . The granodiorite-tonalite intrusive body, which was formed in Upper Proterozoic with Rb- Sr age of ( 946 +24) Ma , constitutes the main host rock . Based on petroche mical, REE and trace ele ments studies of this rock body , the authors hold that the granodiorite- tonalite body resulted from ocean crust melting and represents the basement of the North Qaidam orogenic belt. The N W-trending ductile-brittle shear zone in this region is the main factor controlling the formation of some deposits or ore spots, whereas the for ms , modes of occurrence and sizes of the orebodies are controlled directly by faults or fissures induced from the regional N W-trending shear zone . In this deposit , the quartz vein type ore is predominent , and the mylonite-type gold ore possesses the second place . The hydrothermal alterations related to gold mineralization consist primarily of silicification , pyritization and sericitization , and show weak zonation from the orebody to its wall rock. rothermal alteration sericite separated from mylonite- type gold ore yields an Ar- Ar age of ( 426 +2) Ma . Inaddition, there exists a goldbearing quartz vein that cuts the Indosinian ranite in the east of the ore district, whose whole- rock K- Ar age is ( 21 0 +3) Ma based on the l: 50000 regional geological map . It can thus be concluded that this deposit is an orogenic quartz vein subtype gold deposit and underwent a multiple orogenic process comprising Late Caledonian ductile deformation and Late Variscan to Indosinian orogeny. |
| keywords:orogenic gold deposit, geological characteristics, metallogenetic epoch, Saibagou, Qinghai Province |
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