| 华南加里东期金矿床的基本特征 |
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| 引用本文：.2002.Water/ rock Ireraction During Formation of Skarn-type Deposits in Yueshan Ore field, Anhui Province[J].Mineral Deposits,21(1):1~9 |
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| 基金项目:国家攀登课题A-30 |
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| 中文摘要:华南加里东期金矿床分布广泛, 既可产在华南加里东褶皱带内, 也可发育在毗邻的江南隆起上。其共同特征是矿床产在加里东期构造变形带或变质带中， 受深大断裂带及其分支构造所控制，成矿物质主要来自赋矿围岩。产在隆起上的矿床赋矿围岩时代较老，均为元古宙变质细碎屑岩类~ 矿物及元素组合比较简单，常见单金型。产于褶皱带中者其围岩除元古宙-寒武纪变质细碎屑岩外，还有火山岩、侵入岩及沉积岩，时代为元古宙-志留纪; 矿物及元素组合比较复杂,可见到砷、锑、汞、碲矿物及沥青出现。隆起上的矿床属于加里东期改造作用形成， 褶皱带中者为改造、受改造及斑岩成矿作用的产物。成矿时代除加里东期外，还有燕山期及震旦纪矿化存在。两种构造中的矿床成矿差异主要受物质来源岩石类型、后期叠架作用及岩浆活动所控制。 |
| 中文关键词:加里东期金矿床 华南褶皱带 成矿共性与差异 控制因素 江南隆起 |
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| Water/ rock Ireraction During Formation of Skarn-type Deposits in Yueshan Ore field, Anhui Province |
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| Abstract:The Yueshan ore field is a typical skarn-hydrothrmal Cu-Au ore field in the Middle and Lower Yangtze Valley metallogenic belt. The skarn rocks and ores in the skarn ore deposits show spatial zoning. Wall-rock alterations are well developed around the ore bodies. Their formation can be subdivide d into three stages: the early stage, comprising scapolitization, diopsidization, garnatization, albitization, zoisitization , tre molitization and actinolitization; the middle stage, composed of epidotization, chloritization, silicification and carbonization; the last stage, consisting of carbonization, silicification, argillation, sericitization and chloritization . Analyses in thispaper indicate that the skarn rocks are metasomatic ones formed by the water- rock interaction between the magmatic dominant fluids and the wall rocks . In the ore-for ming process of the skarn ore deposits, the Yueshan intrusive body underwent alteration through high to lower temperature of wate-rock interaction processes. The concentrations of such elements as Si, K, Fe, Mn and Mg got higher in the hydrothermal solution during alteration , which see ms to be of great importance in the enrichment of ore-forming material in the fluid ore-forming system.There were no sharp changes in the volume of dioritic rocks after the high temperature alteration; nevertheless, after the low to moderate temperature alteration, except carbonization, the rock volume increase dover 20 percent , and some space was thus provide d for the location of ore bodies. Infiltration is the major transportation for m of the ore-forming elements, and is also a necessary condition for the formation of large-size ore bodies.The zonal structures of skarn rocks , mineralizations and alterations are products of time- space separation of themineral and element associations through a series of dissolution and deposition reactions , and also a reflection of complex results of such processes or factors as the fluid infiltration velocity , the rate of homogeneous phase reactions, the rate of multiphase reactions , and the velocity of dissolution and deposition waves during the wate-rock interaction. The water-rock ratios in this ore field were lower than 0.1, and the water-rock interactions took place in an open fluid system. The concentration gradient accelerate d the fluid migration and the fur the r water- rock interaCtlon. |
| keywords:skarn ore deposits, water rock interaction, fluid ore-for ming syste m, dyna mics, Yueshan ore field |
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