Portal de Periódicos da CAPES

Patrones químicos y origen del depósito de oro de La Libertad, Chontales, Nicaragua

2011; University of Costa Rica; Issue: 17 Linguagem: Inglês

10.15517/rgac.v0i17.13316

2215-261X

Mauricio Darce, Beatriz Levi, Olav Nyström,

Botany and Geology in Latin America and Caribbean

The La Libertad region is situated in the central part of Nicaragua, within a broad discontinuous belt of Tertiary volcanic rocks that contains several epithermal gold and silver deposits and extends from Guatemala (and Mexico) to Costa Rica. A chemical comparision between altered and unaltered basic lavas of this area shows that chemical changes associated with the geothermal field type of alteration centered at the mining district reach more than 5 km away from it. Water content, CO2, K and S have beeen added, titanium seem to have been inmobile and Cl partily lost from the fossil geothermal system. Gold, originally concentrated in the glass of basic lavas, was leached during zeolite facies conditions and precipitated with silica in fractures, forming veins on the center of the geothermal field. An estimate shows that the amount of Au released during the alteration was sufficient to give origin to La Libertad deposit.