The Hydrothermal Alteration of the Cordón de Inacaliri Volcanic Complex in the Framework of the Hidden Geothermal Systems within the Pabelloncito Graben (Northern Chile)

Detailed mineralogical analyses in areas with surface hydrothermal alteration zones associated recent volcanism (<1 Ma) the Central Andean Volcanic Zone could provide key information to unravel presence of hidden geothermal systems. In Cordón de Inacaliri Complex, a field an estimated potential ~1.08 MWe·km?2 has been recently discovered. this work, we focus on and discharge products area, aim reconstruct geological processes responsible for space-time evolution leading records. We identified (1) acid fluids that be related to: (i) acid-sulfate alunite + kaolinite opal CT anatase, indicating steam-heated blanket massive fine-grained silica (opal-CT), likely accumulated mud pots where intersection paleowater table occurred; (ii) argillic hematite halloysite smectite I/S illite surrounding alteration; (2) neutral-alkaline such as: discontinuous pinnacle-like deposits laterally developed coarse stratification which, together remaining microorganisms, emphasize sinter deposit alkaline/freshwater/brackish alkaline-chlorine water bodies calcite aragonite deriving from bicarbonate waters. The scarce relics deposits, high degree crystallinity phases diatom remnants, addition anatase assemblages, is consistent superimposition environment previous deposit. These characters are also distinguishing feature paleosurface system Complex. diatoms heated freshwater at 5100 m a.s.l. Atacama Desert last documented deglaciation area (~20–10 ka), important factor recharge systems Pabelloncito graben.