The southern part of Barru is exposed to mineralized tracheal rocks in contact with the limestone of the Tonasa Formation, while in the northern part there is an intrusion of mineralized dacite which penetrates the marl of the Tonasa Formation. The research objective was to determine the chemical characteristics of sulfide alteration and mineralization in trachea and pyrite in limestone. Using petrographic and XRF methods, it is known that sericite, orthoclast alteration and mineralization of galena, chalcopyrite, pyrite in trachea are probably the source of different magma. The calcite carbonate mineral in limestone undergoes sulfide substitution that also results in chemical transformations of Ca, Si and S. Weathering of limestones correlates with hydrothermal solutions, which is supported by a moderate alteration index for the formation of clay minerals, which apparently does not affect limestones. Simultaneously, at moderate alteration conditions Na2O decomposition, K2O replacement pyrite in the cavity filling and occurs in the sulfide phase, hematite oxidation. [ABSTRACT FROM AUTHOR]