Sedex型矿床成矿系统  

METALLOGENIC SYSTEM OF SEDEX TYPE DEPOSITS: A REVIEW

作　　者：韩发[1] 孙海田[1] 

机构地区：[1]中国地质科学院矿床地质研究所

出　　处：《地学前缘》1999年第1期139-142,共4页Earth Science Frontiers

摘　　要：系统总结了Ｓｅｄｅｘ型矿床产出的构造背景、地质环境、矿床地质地球化学特征、矿化流体来源及成矿模式等问题。结合某些最新研究成果，对该类型矿床的Ｐｂ、Ｓｉ、Ｂ同位素地球化学进行了综合研究，并以加拿大科迪勒拉地区页岩容矿的ＺｎＰｂ矿床、中国大厂锡多金属矿床及澳大利亚布罗肯希尔ＰｂＺｎＡｇ矿床为例，深入讨论了Ｐｂ、Ｓｉ、Ｂ的来源及其对矿床成因的指示意义。对产于不同地质环境下现代海底热液成矿系统的研究证明，有沉积物覆盖和无沉积物覆盖海底成矿热流体的化学组成及Ｐｂ、Ｓｒ、Ｂ稳定同位素地球化学明显不同。前者富含与陆壳物质有关的金属组合及ＮＨ４，并富含放射成因Ｐｂ和Ｓｒ的组分，后者富含与洋壳玄武岩有关的金属组合，但特别贫ＮＨ４。这种不同与古代Ｓｅｄｅｘ型和塞浦路斯型矿床之间化学组成的差别十分相似，它意味着前者成矿物质主要来源于下伏陆壳岩石，并为其富含Ｂ，Ｂａ，Ａｇ，Ａｓ，Ｓｂ，Ｗ，Ｓｎ，Ｈｇ，Ｍｎ等元素提供了合理的解释。在此基础上，笔者指出，在特定地球化学背景下，上述那些元素也能形成独立的Ｓｅｄｅｘ型矿床。The tectonic settings,geological environments,geology geochemical features and the source of ore forming fluids for Sedex type deposits are reviewed in this paper.The Pb,Si,B isotope geochemistry for deposits of this type is especially studied in the light of some recent data,and taking the shale hosted Zn Pb deposits in Canadian Cordillera,the Dachang tin polymetallic deposits in China and the Broken Hill Pb Zn Ag deposits in Australia as examples,the paper goes further into constraints from Pb,Si,B isotope on the origin and source of these deposits.The models of ore genesis are also discussed.In order to make a comparison between the modern and the ancient massive sulfide deposits,this paper has a description and discussion on metallogenesis of the modern geothermal systems.The results show that chemical and Pb,Sr,B isotope compositions of the hydrothermal fluids and ores from sediment covered and sediment free ridges are quite different.The former is enriched in Pb,Ba,Ag,As,Sb,Sn,Mn,Cd,Rb,Cs,Sr,Br,I,B elements,and NH 4 as well as in radiogenic Pb and Sr components,but poor in Cu metal relative to the latter,which is very similar to that between Sedex type and Cyprus type of deposits.This suggests that the ore sources of Sedex type deposits are mainly derived from continental sediments and explains why contents of the elements mentioned above are generally high in them.Based on these facts,it is concluded that sediment hosted W, Sn,Sb,Mn,Hg or B deposits should occur in certain districts with some specific geochemical backgrounds besides Pb Zn (Ba) (Ag) deposits known in the world.

关 键 词：SEDEX型矿床 矿床地质学 成矿模式 成矿系统 

分 类 号：P611[天文地球—矿床学]