New geochemical investigations in Platanares and Azacualpa geothermal sites (Honduras)

作者：Barberi Franco; Carapezza Maria Luisa^*; Cioni Roberto; Lelli Matteo; Menichini Matia; R****di Massimo; Ricci Tullio; Tarchini Luca

来源：Journal of Volcanology and Geothermal Research, 2013, 257: 113-134.

DOI：10.1016/j.jvolgeores.2013.03.011

• Geothermal perspectives of Honduras
• Water and gas geochemistry
• Geothermometric estimations
• CO2 soil flux investigation for the assessment of permeability at depth

Platanares and Azacualpa geothermal sites of Honduras are located in an inner part of the Caribbean Plate far from the active volcanic front of Central America. Here geology indicates that there are not the conditions for the occurrence of shallow magmatic heat sources for high-enthalpy geothermal resources. Geothermal perspectives are related to the possibility of a deep circulation of meteoric water along faults and the storage of the heated fluid in fractured permeable reservoirs. Geochemical geothermometers indicate a temperature for the deeper part of the geothermal reservoir close to 200 degrees C for Platanares and of 150-170 degrees C for Azacualpa. Calcite scaling, with subordinate silica deposition has to be expected in both sites. CO2 soil flux investigations have been carried out in both areas and reveal the presence of positive anomalies likely corresponding to the presence at depth of fractured degassing geothermal reservoirs. Compared with the geothermal areas of Central Italy whose reservoirs are hosted in carbonate rocks, e.g. Latera (Chiodini et al., 2007), the CO2 soil flux measured in Honduras is significantly lower (mean of 17 g/m(2)day at Platanares and of 163 g/m(2)day at Azacualpa) probably because of the dominant silicate nature of the deep reservoirs.

• 出版日期2013-5-1