Geothermal Features of Armenia: A Country Update

Abstract

Sixty heat flow values ranging from 38 to 157 mW/m2 have been estimated for Armenia from geothermal gradient determinations in 90 locations and a limited number of thermal conductivity determinations. The highest values of heat flow (90-157 mW/m2) occur in the central part of the country, which is characterized by vigorous Quaternary volcanic activity, manifestations of thermal springs, intensive aeromagnetic anomalies, and minimal negative values of Bouguer anomalies. To the northeast and southeast from this region, heat flow goes down to background values which is estimated to be 45-55 mW/m2. It is found that a substantial part of the heat flow anomaly is caused by local shallowdepth heat sources, which must be cooling magmatic chambers related to recent volcanic activity. Based on magnetic investigations, depths, sizes, and current temperatures of magmatic chambers are estimated. An aeromagnetic data analysis shows that Curie point depth in Armenian territory varies from 5 (in volcanic region) to 12-13 km. Reservoir temperatures of mineral waters, estimated by silica geothermometry, generally range from 40oC to 160oC. The Eastern volcanic belt is thought to be the main area of geothermal potential in Armenia where both dry and hydrothermal resources are expected. The zones of deep faults almost everywhere in Armenian territory are promising for hydrothermal resources.