Keywords
campos geotérmicos
volátiles
gases nobles
manto superior
produccióngeotérmica
central america
geothermal fields
volatiles
noble gases
upper mantle
geothermal production
How to Cite
Abstract
Gases from geothermal production wells in Costa Rica, Nicaragua, and El Salvador were collected and analyzed for major and noble gas composition in order to determine the sources of volatiles in activeCentral American volcanic systems. Ratios of 3He/4He indicate that the upper mantle is the principal source ofhelium, with minor amounts derived from the crust in the Berlín field of El Salvador. The Miravalles field ofCosta Rica is characterized by high CO2/3He ratios which are likely a product of increased devolatilization inthe southwestern portion of the Cocos plate. The Momotombo field of Nicaragua shows high nitrogen and methane concentrations, both of which are likely the product of local contributions within the Nicaraguan Depression. The Central American arc is, in general, characterized by high N2/3He ratios and high 3He/4Heratios, a combination which is unusual for island arc systems. The results demonstrate that understanding thegas systematics in geothermal systems, both during initiation and during commercial production, is essential inthe planning and maintenance of this important resource.