安徽沿江地区岩浆成矿带

安徽沿江地区可分为三个岩浆成矿带：内带（主带） 、北（ 外） 带和南（ 外） 带。内带沿长江断裂带分布，与地幔隆起带一致，幔源高钾碱性玄武岩浆通过不同程度的ＡＦＣ混合机制和结晶分异机制，形成了不同的岩石组合和矿床，基性岩到酸性岩均有分布，其共同点是高钾富碱，侵入岩以高钾钙碱性岩系为主，火山岩以橄榄安粗岩系为主，广义矽卡岩型Ｃｕ、Ｆｅ、Ｓ、Ａｕ 及火山岩型Ｆｅ、Ｓ矿床是主要的矿床类型；南（外） 带以花岗闪长斑岩为主，高硅低碱，属钙碱性岩系，是上地壳下部易熔组分重熔的产物，成矿元素也由主带的Ｃｕ、Ｆｅ、Ｓ、Ａｕ 转向Ｐｂ、Ｚｎ（Ａｇ） 、Ｃｕ、Ｍｏ、Ｗ 等，是斑岩型Ｍｏ、Ｃｕ 矿床的远景带；北（外） 带比较复杂，主体部分属钙碱性岩系，花岗岩与花岗闪长岩侵入体是下地壳重熔的产物，部分花岗闪长斑岩形成广义矽卡岩型Ｃｕ、Ａｕ 矿床，另一部分以幔源物质为主的闪长玢岩，形成斑岩型Ｃｕ 矿。不同的岩浆成矿带受不同的基底控制。Ｎｄ 、Ｓｒ、Ｐｂ 同位素研究表明，主带和北带存在太古宙麻粒岩相变质基底，南带岩浆岩则源于元古宙角闪岩相到绿片岩相变质基底。地幔隆起与幔源物质参与成矿作用，以及由地幔隆起带来的高热流是成矿的最有利条件。建议深入研究幔脊

THE MAGMATIC METALLOGENETIC BELT AROUND THE YANGTZE RIVER IN ANHUI

Three magmatic metallogenetic belts can be delimited around the Yangtze River in Anhui such as the inner belt(major), north(outer) belt and south(outer)belt The inner belt extends along the Yangtze rift coinciding with the mantle rise The mantle-sourced high pottassium alkaline basaltic magma formed variety of lithological association and deposits ranging from basic to acidic by varying extent AFC-mixing mechanism and crystalization differentiation mechanism The rocks are commonly with high pottassium and rich alkali The intrusive rocks are mainly of high potassium calc-alkaline series and volcanic rocks of oliver latite series The major deposits include the broad-sensed skarn-type copper, iron,sulphur and gold ones and the iron-sulphur ones The south(outer) belt is substantially composed of granodiorite porphyry with high silicon and low alkali belonging to calc-alkaline series resulted from the remelting of the lower easily fusible part of the upper crust The ore-forming elements change into Pb,Zn(Ag),Cu,Mo,W,etc from Cu,Fe,S and Au in the major belt So the south belt is prospective for porphyry type Mo and Cu deposit The north(outer)belt is complicated Its principle part belongs to calc-alkaline series The granite and granodiorite intrusives are resulted from the remelting of lower crust Some of granodiorite porphyrys formed the broad-sensed skarn type Cu and Au deposit while the mantle-sourced diorite porphyrite the porphyry type Cu deposit Different magmatic metallogenetic belts are controlled by diverse basements The Nd,Sr and Pb isotopic study indicates that the major and north belts have granulite facies metamorphosed basement whereas the south belt of magmatic rocks are sourced from the Proterozoic amphibolite facies to green schist facies metamorphosed basement The favourable metallogenetic conditions are mantle rise,mantle-sourced substance participating in ore-forming and high thermal flow brought about by mantle rise