Study On Geochemical Characteristics And Gold-bearing Mineral Of The Longtoushan Gold Deposit In Guangxi

On the basis of analysis on the geological characteristics,the mineral assemblage , the ore structure and texture , ore-forming elements ,rare earth elements, stable isotopes and geochemisry of fluid inclusions ,and by synthesis of the informations summed up by predecessors, this paper attempt to discuss the genesis of gold deposit .And the studies of the characteristics of Pyrite and the occurrence of gold in Pyrite try to find the distribution of the invisible gold.The deposit belongs to middle-lower temperature sub-volcanic hydrothermal gold deposit. Pyrite is the major gold-bearing mineral in the deposit. The ratios of Co/Ni of pyrite are all> 1. In order to solve the problem of the gold occurrence, selective solution were used and the result shows that the supermicro grain gold inclusion occupy 95.5% and the lattice gold is 4.5%。The total content of REE in ores and granite rocks is lower than the regional stratigraphy. The right dipping of REE partitioning curves shows rich in light rare earth elements. The oxygen isotope compositions in the fluid suggest a mixing genesis of magmawater with meteoricwater. The character of sulfur isotope shows multiple origins of sulfur in mineralization fluid, mainly from volcanic-intrusive complex and the basement strata. It is assumpted from lead isotope characters that lead is mainly origin from Mesozoic volcanic rocks and partly from basement rocks. It is therefore believed that the ore forming matter of the deposit is mainly origin from magma of the mantle and partly from strata. The temperature for mineralization is middle-lower temperature.