Interplay of Volcanism and Structural Control in Defining the Geothermal System(s) along the Liquine-Ofqui Fault Zone, in the South-Central Chile

Abstract

Two distinct domains of the geothermal systems, viz. structural (or non-volcanic) and volcanic have been identified in the southcentral Chile, based on the chemistry of the thermal discharges and structural analysis of the lineaments. These two domains are distinct in their ways of heating up of meteoric water, which is the feeder to these geothermal systems. The geothermal system(s) of the volcanic domain are associated with the regional volcanic centers. The process of heating is through deep circulation of meteoric water in the case of the geothermal system(s) of the structural (non-volcanic) domain. In the case of the geothermal system(s) of volcanic domain, the heating of the meteoric water is through absorption of heat and condensation of steam and gases by meteoric water during lateral circulation. However, these thermal discharges do not exhibit the typical signatures of steam heated waters, which are subdued through water-rock interaction and other near surface processes