Regional and Local Geologic Structure of the Momotombo Field, Nicaragua

Abstract

The regional geologic-tectonic setting of northwestern Nicaragua is the result of subduction. Differential plate margin movement and segmentation formed a deep rift paralleling the Middle American Trench. Deep seated shear faults provided access to sublithospheric magmas to create the Nicaraguan volcanic chain. Volcan Momotombo is the southernmost volcano of the Marabios Range of northern Nicaragua. It host a proven geothermal resource knows as the Momotombo Geothermal Field, located within a small graben structure and measuring less than one square kilometer. This geothermal productive area appears not to be a geothermal reservoir, but rather part of a thermal convection system. Wells in the central and eastern part of the field have diminished in output and temperature. The presence of a temperature inversion zone, clearly distinguishable in the eastern end of the field, indicated that no conductive heating of the productive zone is taking place.