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

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.