安徽铜陵天马山矿床与大团山矿床流体成矿作用对比研究

CONTRAST IN FLUID MINERALIZATION BETWEEN TIANMASHAN AND DATUANSHAN ORE DEPOSITS, TONGLING, ANHUI

对安徽铜陵天马山矿床和大团山矿床的成矿地质背景和成矿流体特征 ,特别是流体成矿作用进行了较系统的对比研究 ,在此基础上探讨了在铜陵天马山和大团山矿区分别形成层控矽卡岩型金硫矿床和层控矽卡岩型铜矿床的主要原因 .研究结果表明 ,在天马山矿区之所以形成金硫矿床 ,主要与岩浆岩岩体本身含金高而含铜低 ,围岩地层中有含有机质的赋金黄铁矿层存在 ,并且主成矿阶段的成矿流体以岩浆流体为主有关 ;而在大团山矿区之所以形成铜矿床 ,主要原因是岩浆岩岩体本身含铜高 ,成矿流体富铜 ,且主成矿阶段的成矿流体以地下水流体为主 .当然 ,流体成分演化和物理化学条件改变方面的差异导致铜或金在流体成矿过程晚期逐步分散也是这两个矿区分别形成不同类型矿床的重要原因 .

A comprehensive contrast in the metallogenic geological background and metallogenic fluid feature, especially fluid metallogeny has been performed between the Tianmashan and the Datuanshan ore deposits, Tongling, Anhui. The major reasons for the formation of the stratabound skarn Au S ore deposit in Tianmashan and for that of the stratabound skarn Cu ore deposit in Datuanshan are analysed in accordance with this contrast. The magmatic pluton in Tianmashan is rich in Au and poor in Cu, but that in Datuanshan is rich in Cu and Au. The wallrock strata in Tianmashan contain Au bearing pyrite layers with some organic substance but those in Datuanshan contain no such layers. Moreover, the metallogenic fluid in Tianmashan is dominated by magmatic fluid in the major metallogenic stage, but that with high content of Cu in Datuanshan by groundwater fluid. These three contrasts account for the formation of the stratabound skarn Au S ore deposit in Tianmashan and that of the stratabound skarn Cu ore deposit in Datuanshan. In addition, the differences between compositional evolution and physico chemical condition variation of the metallogenic fluid resulting in gradual dispersing of Cu or Au in the late stage of the fluid metallogeny is also an important cause for the generation of the stratabound skarn Au S ore deposit in Tianmashan and that of the stratabound skarn Cu ore deposit in Datuanshan.