摘要
根据华南六个有代表性金矿的成矿时代、断裂构造、围岩、侵入岩、中基性岩墙、成矿类型、成矿阶段、矿石组成、成矿温度、包裹体成分以及稳定同位素等多方面研究，发现华南大部分金矿具有共同特征：主要成矿时代为燕山期，远落后于围岩时代；是沿地壳级大断裂形成的后生矿床；六个金矿的铅同位素组成均可分出高值区（组）和低值区（组），表明成矿物质有深浅两个不同来源；不同金矿氢、氧同位素指示成矿热液水为深源岩浆水与古大气降水两个来源水的混合。因此，华南金矿成矿物质和成矿热液水，既有通过地壳断裂来自深部下地壳或上地幔的，又有就地取材汲取上地壳古老变质围岩的，从而称为深浅二元混合成矿模式。
In recent years,gold mining and prospecting have been developed rapidlyin South China. The representative gold deposits,such as Hetai,Xinzhou,Nancbong,Longshui,Pangxidong and Baoban, are considered to be of diffe-rent ages and genetic types,The genesis of the gold deposits is interpretedcommonly by the polynary theory. According to country rocks,intrusions,intermediate-basic dikes, mineralization types, mineralization stages,oremineral compositions,mineralization temperatures, fluid inclusion compositi-ons and isotopic ages, however, we have found that they are mainly Yansha-nian(100 × 10￣6～114×10￣6 a or 150 ×10￣6～180 × 10￣6 a) products and all belong tothe same epigenetic mineralization type,formed much later than pre-Cam-brian and Caledonian metamorphic country rocks and granites. The deepfaults, which cut into lower crust or upper mantle and provided favorablecbannels for deep-source gold materials,frequently occur flanking these golddeposits. In the diagrams of ￣(208)Pb/￣(204)Pb versus ￣(206)Pb/￣(204)Pb and ￣(207)Pb/￣(204)Pbversus ￣(206)Pb/￣(204)Pb(101 data ),the distribution of ore lead isotopes in thesegold districts can be divided into the high value region(A,B,C,D, E andF)and the low region(A',B',C',D',E'and F'),The high value regioncorresponds to the upper crustal metamorphic country rocks(W)of golddeposits, whereas the low corresponds to deep Yangtze series(Series Ⅱgranites)( Ⅱ ). This shows that lead isotopes of these gold deposits werederived from two sources-one from upper crustal metamorphic rocks,and theother from deep sources,including Series Ⅱ granites,intermediate-basicdikes,lower crust and upper mantle. In the diagram of δD_(H_2o) versus δ￣(18)O_(H_2o),138 data for these ore deposits fall mainly into the transitional area betweenthe meteoric water line and the magmatic water district,suggesting thatwater of these hydrothermal gold deposits may be divided into two kinds meteoric water and deep source water,including magmatic water. Therefore,although the gold deposits in South China appear very complicated in ageand genetic type,they are actually rather simple and belong to the sameepigenetic meso-epithermal type formed much later than country rocks.They are Yanshanian in age and their mineralization materials and watersources must have been derived from deep crust or upper mantle throughdeep faults,as well as from upper crust and paleometeoric water,So,themetallogenic model might be called binary(deep and low-source)mixed modelof gold mineralization.
出处
《矿床地质》
CAS
CSCD
北大核心
1995年第1期1-11,共11页
Mineral Deposits
关键词
二元混合成矿
成矿模式
稳定同位素
gold ore deposits in South China,binary mixed mineraliza-tion,metallogenic model,stable isotopes
