| 山东蓬家夼金矿床成矿流体地球化学特征 |
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| 引用本文：.2000.Geochemical characteristics of ore-forming fluids in the Pengjiakuang gold deposit, Shandong Province[J].Mineral Deposits,19(3):235~244 |
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| 基金项目:中国科学院创新工程项目KZCX1-Y-03和中国科学院黄金九五重大项目KZ951-A1-404-02-02专题 |
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| 中文摘要:胶东地区存在3种类型的金矿床，蚀变岩型（焦家式）和石英脉型（玲珑式）已经广为重视。最近在胶莱盆地的东北缘发现了一种新型金矿床 层控型金矿床，以蓬家夼金矿床和宋家沟金矿床为代表。蓬家夼金矿床赋存在胶莱盆地东北缘拆离断层带中，产于莱阳组砾岩与荆山群地层的构造接触部位，是在燕山期火山-岩浆活动期间在大气水和岩浆水的参与下形成的。围岩遭受了强烈的硅化、绢云母化、碳酸盐化和黄铁矿化等蚀变作用。单个矿体最大长度800 m。宽度在500 ~ 700 m之间，金品位(1~43)×10-6。矿石中流体包裹体发育，主要为气液相N aCl-H2O包裹体以及少量的含液相CO2的NaCl-CO2-H2O型包裹体。成矿热液气相成分以H2O、CO2为主；液相成分中富Na+、Cl-，贫K+、F-；fO2为8 9×10-40～5.9×10- 40Pa; 氧化还原位为0.46 ~ 0.52 eV，为弱还原环境。成矿流体δ18OH2O为0 6‰~ 4.0‰，δDH2O为-90‰ ~ -98‰，反映出成矿流体由大气水和岩浆水混合组成酌特点。流体混溶、水-岩反应和古大气水的混入是造成蓬家夼金矿床流体化学组成变化、金沉淀成矿的主要因素。 |
| 中文关键词:流体包裹体 成矿流体 地球化学 蓬家夼金矿床 山东 |
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| Geochemical characteristics of ore-forming fluids in the Pengjiakuang gold deposit, Shandong Province |
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| Abstract:The are th ree types ofgold deposits in Jiaodong gold metallogenic area. The altered rocktype ( Jiaojia type) and quartz vein type (Linglong type) were discovered several years ago. In recent years, a new type of gold deposits, viz., stratabound gold deposits, such as the Pengjiakuang gold deposit and the Songjiagou gold deposit, were discovered on the northeast-ernmargin of Jiaolai basin. The Pengjiakuang gold deposit occurs in a detached fault between conglome rate of Early Cretaceous Laiyang Formation and metamorphic complex of Lower Proterozoic Jingshan Group on the margin of Jialai basin. Formed be fore Yanshanian volcanic period, it was related to meteoric water and magmatic water. The host rocks have been extensively subjected to pyritization, silicification, sericitization and carbonatization. Individual ore-bodies have maxrmum length of 800 m, oblique extension of 500~ 700 m and gold grade of l×10-6~ 43×10-6. The ore-forming fluids are rich in Na+ and Cl- but relatively impoverished in K+ and F-. In the main ore-forming stage. fO2 and Eh values are 8. 9×10-40 ~ 5.9×10-40 Pa and 0.46 ~ 0.52 eV respectively. The fluids in the inclusions have a wide range of homogenization temperatures from 200℃ to 340℃; nevertheless, the best tem perature range for gold deposition is from 280℃ to 320℃. According to the data of hydrogen, oxygen isotopic com position (δ18OH20=0.6‰~ 4.0‰, δDH2O= -90‰ ~ -98‰), the conclusion can be reached that ore-forming fluids of the Pengjiakuang gold deposit seem ed to be a kind of mixed hydrothermald solution which was mainly composed of meteoric water and magm aticwater. Fluid immiscrbility and fluid-rock interaction might have been the main factors for gold deposition in the mine. |
| keywords:fluid inclusion, ore-forming fluid, geochemical characteristics, Pengjiakuang gold deposit, Shandong Province |
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