SOURCE OF GROUND-WATER IN THE DESERTS OF NORTHERN CHILE - EVIDENCE OF DEEP CIRCULATION OF GROUND-WATER FROM THE ANDES

Ground water in the Pampa del Tamarugal basin part of the desert of Northern Chile is the main water resource for cities and agricultural activities in the region. As the area received virtually no precipitation, the source of the ground water is rains in the high Andes. Aquifer recharge has been linked to a drainage system associated with this part of the Andes. Ground‐water flow is from northeast to southwest, and a flow component from east to west is also observed in some parts of the basin. In general, the water becomes very saline towards the western part of the basin, giving rise to salt lakes (salares) in ground‐water discharge areas. However, isotopic, chemical, and geological evidence plus ground‐water temperatures distribution, suggest the existence of a different recharge mechanism linked to a regional ground‐water flow system. It is suggested that low‐salinity water emerges from ground water recharged in the high Andes through a basement fault system underneath the basin. This model has implications for the future exploration for new fresh‐water resources. Copyright © 1990, Wiley Blackwell. All rights reserved