SURFACE ALTERATION MINERALS AS FLUID FLOW INDICATORS IN A GEOTHERMAL SYSTEM: THE CASE OF LICANCURA, NORTHERN CHILE

MAZA S.N.; MORATA D.; CAMUS, E.; GODOY B.; PIZARRO, M.; MORATA D.

Granada

Congreso; 16 International Clay Conference; 2017

International Clay Conference

Geothermal activity can be evidenced on surface by mean of alteration minerals [1,2] Because these minerals are the result of interaction between host rocks and geothermal fluids, these minerals can give us information about characteristics of the geothermal fluids (i.e. temperature, pH) [3, 4] and allow tracking changes on it. Within this group of minerals, it is important to highlight clay minerals, because of their susceptibility to minor changes, reflecting the processes occurring in the system [5, 6], which allow us to determinate zones of geothermal fluid flow. In this work we present preliminary results in the study of surface alteration minerals of a geothermal system. The case of study corresponds to Licancura, placed 220 km2 NE to Iquique, between 3600 and 4200 m.a.s.l. in the High Andes. The outcrops in this zone corresponds to Miocene andesitic to dacitic lava and tuff rocks which have evidence of tectonic activity as faults and fractures. In this zone is possible to observe large extensions of alteration minerals on surface which give us information about paleofluids and minerals precipitating in actual hot springs zones which give us information of actual fluids. From this zones, covered by alteration minerals we took samples to analyze by X-ray diffraction, using the powder method for total rock samples and oriented clay mineral aggregates for the fraction