A Geochemical Reconnaissance of Thermal and Nonthermal Waters in Nicaragua

Abstract

Instituto National Electridad (INE), the Nicaraguan utility company, commissioned a Master Plan for Electrical Development in that country which included a Geothermal Resources Inventory. Geothermal exploration and evaluation integrated geological, geochemical, and geophysical surveys. The geochemical reconnaissance had a two fold purpose: 1) to detect and define areas of regional geothermal potential, and 2) to support site specific targets for exploration drilling suggested by the other surveys. Two hundred thirty-five localities were sampled: 43 springs and 192 wells. Samples from cooler springs and wells were collected around thermal waters so that relative anomalies might be recognized. The area covered over 20,000 square kilometers, in or bordering the Nicaraguan Depression. Several geochemical anomalies were discovered, aligned along north south or northwest southeast trends. Geophysics has defined several deep, primary reservoirs. Thermal manifestations are usually absent at the surface but are present where secondary, shallower reservoirs occur.