中国东部铜矿床类型、成矿环境、成矿集中区与成矿系统

TYPES,GEOLOGICALBACKGROUND,METALLOGENIC PROVINCESANDORE_FORMINGSYSTEMATICSOF MAJORCOPPERDEPOSITSINEASTERNCHINA

通过对我国东部２２ 个大型以上及４０ 余个中型铜矿床的综合调研， 并与国外对比得出如下结论： ①中国中东部陆壳是在几个古陆块基础上增生起来的， 铜矿成矿作用在空间上向板块边缘推移， 与块体边缘地球化学急变带有密切联系， 在时间上越来越新； ②大型铜矿可分６ 大成矿期， 以中生代最重要， 次为晚古生代、中（ 新） 元古代； ③我国东部地壳运动频繁而又比较强烈， 就形成大型铜矿床的环境而言， 内生成分较多的矿床类型比外生成分较多的矿床类型可能更有利。铜矿床可分９ 大类型， 斑岩型最有潜力。提出并论证铜质得以大规模堆积的４ 类成矿系统； ④划分出９ 个成矿集中区、远景区； ⑤分析了中国东部中生代火山侵入岩带的构造性质及中国东部斑岩铜矿规模上不如美洲西岸的原因。

Based on a comprehensiveinvestigationinto 22 large_sized and over 40 medium_sized copper depositsin eastern Chinain comparison with some copper depositsabroad ,this paper hasreached thefollowing conclusions:(1) The continental crustin eastern China was formed by accretion around several older massifs throughout the geological ages, which led to the migration of the metallization oflarge copper depositstowardsthe marginsofthe old plates with thelapse oftime. Therefore,large copperdepositsin eastern China mostly occuralong marginsofplatforms,accre tionary fold belts and intracontinentalfaulted downwarping belts,showing close relation to the geochemical sharp_ chanege zones along massif margins .( 2 ) There are six major metallogenicepochsforlarge copper deposits in eastern China. Of these the Mesozoicis the most important one,and nextcome Late Paleozoicand Mesoproterozoic.(3) Amongthe ninetypesofcopper de positsfoundin eastern China,the porphyry typeis mostimportant,followed by submarine sedi ments_hosted massive sulfide type,skarn type , VMS, and Cu_Ni type. The submarine sedi ments_hosted massivesuilfidetype,subaerial hudrothermalsedimentary type and subvolcanic hy drothermalvein type copper deposits are three new types proposed by the authors. The EasternChinesecontinentis characterized by varied plate tectonic styles as well as frequent and rather strong crustalactivation .Therefore,sofarastheformation oflargecopper depositsisconcerned, the environmentseemsto be morefavorableforthe depositsof mainly endogenic originthan those dominated by exogenic origin .Thecomplicated multi_cycle crustalactivityin eastern Chinaledto the presence of metallogenicinheritance and 》isolocalization' metallization within a single mining regime.(4) The papersuggests and demonstratesfour metallogenic systematicsin which coppermaterialcan beaccumulated massively.(5) Nine metallogenicprovincesand prospects were delin eated, of which the Lower Yangtze depressive zone,Jiangnan axis and Xikang_Yunnan axis provinces are most important.In addition,this paper also deals with the tectonic property of Mesozoic volcanic_intrusive domainsin eastern China and thefactorsresponsibleforthe factthat porphyry copper depositsin eastern China are much smaller in size and quantity than those inwestern America