Results from a Soil CO2 Flux and Shallow Temperature Survey at the San Jacinto-Tizate Geothermal Power Project, Nicaragua

Abstract

A 609 point soil CO2 gas flux and shallow temperature survey was undertaken to determine if postulated structural features are associated with elevated CO2 flux and/or shallow (¡Ü 1m) subsurface temperatures in an area of ~20km2 in and around the San Jacinto-Tizate geothermal power project, Nicaragua. The main objective of the survey was to assist with well targeting and in helping to refine the conceptual model of the San Jacinto-Tizate geothermal system.

The survey confirmed the previously mapped NNE striking faults, and indicates that there is fairly widespread permeability on those faults, and also on the margin of a diorite intrusive which marks the eastern margin of the field. This survey also indicates a previously unmapped NNE trending fault passing through the El Tizate area. In addition, a large area of anomalous CO2 flux occurs on a major mapped fault to the west, and along with a magnetotelluric anomaly and distant thermal features provides evidence for a geothermal system just to the west of El Tizate.