川西农都柯火山岩型低温热液Au-Ag多金属矿床的特征与成因 |
点此下载全文 |
引用本文:.2001.Characteristics and Origin of the Nongduke Volcanic Epithermal Au-Ag Polymetallic Deposit in Western Sichuan Province[J].Mineral Deposits,20(3):199~207 |
Hits: 3574 |
Download times: 1926 |
|
基金项目:国家“九五”科技攻关项目(96-914-03-05 |
|
中文摘要:农都柯矿床是在义敦岛弧带中旨次发现的火山岩型浅成低温Au- Ag多金属矿床。该矿床产丁弧后扩张盆地的勉戈组流纹岩巾,受韧性剪切带控制。矿床中发育一套典型的低温热液矿物组合,包括辉锑铅矿、辉锑银铅矿、辉锑矿、砷黝铜矿、自然金、黄铁矿、闪锌矿、雌黄、雄黄、登红石(HgO)等。蚀变作用以硅化和绢云母化为主,伴生重品石化和蒙脱石化。按照现行的火山岩型低温热液金-银矿床的分类原则,该矿床应属丁-高硫的酸性硫酸盐型。流体包裹体研究表明,主要成矿过程发生在221~ 130℃之间:成矿流体的温度与盐度演化趋势暗示着矿床之下存在一隐伏岩浆房。硫、铅同位素显示成矿物质主要来自弧后火山岩,矿床是岩浆热液与大气降水对含矿火山岩(矿源层)联合作用的结果。 |
中文关键词:义敦岛弧 火山岩 低温热液 Au- Ag多金属矿床 |
|
Characteristics and Origin of the Nongduke Volcanic Epithermal Au-Ag Polymetallic Deposit in Western Sichuan Province |
|
|
Abstract:The Nongduke deposit is the first volcanic epithermal Au- Ag polymetallic deposit found in the Yidun arc zone. The deposit occurs in the rhyolite area of Miange Formation within the back-arc spreading basin and is controlled by a shearing belt . There develops a typical epithermal mineral association in the deposit, which consists of zinckenite, diaphorite, antimonite, tennantite, native gold, pyrite, sphalerite, orpiment, realgar, and mercury oxide. The alterations are mainly silicification and sericitization, and, subordinately, baritization and mont morillonitization. According to the current classification of the volcanic epithermal goldsilver deposits, the Nongduke deposit should be of high-sulfur acid sulphate type. Fluid inclusion studies show that the main ore-forming process occurred in the temperature range of 130~221℃. The correlation trend between Th and salinity of the ore-forming fluids implies that a buried magma chamber might exist under the deposit. The S, Pb isotope data also indicate that the ore-forming metals were mainly derived from the back-arc volcanics. The deposit was produced by the combined interaction of magmatic fluids and meteoric water recycling through the ore-bearing volcanics . |
keywords:Yidun arc, volcanics, epithermal solution, Au- Ag poly metallic deposit |
View Full Text View/Add Comment Download reader |