Geological Map of the Tocomar Basin (Puna Plateau, NW Argentina). Implication for the Geothermal System Investigation

Abstract

This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau region.

Structural analysis and fluid geochemistry as tools to assess the potential of the Tocomar geothermal system, Central Puna (Argentina)

“…1c). The basin infill consists of shoshonitic lava flows of the Cerro San Jerónimo with ages from 0.78 Ma (Aquater, 1979) to 0.144 Ma (Fernandez-Turiel et al, 2021 and Pleistocene fluvial/alluvial sediments (La Vega Formation; Filipovich et al, 2020) covered by a complex sequence of pyroclastic deposits from the Alto Tocomar Formation (Filipovich et al, 2020). Volcanic products from TVC are mainly rhyolitic in composition (Petrinovic et al, 2005;2006;Petrinovic and Colombo Piñol, 2006) with ages ranging from 1.15±0.3 Ma (Aquater, 1980) to 0.55±0.1 Ma (Petrinovic et al, 1999).…”

“…However, the basin origin still remains unclear (e.g. Filipovich et al, 2020). This local extensional component of motion has been thought as the key factor for the enhanced magma storage and fluid circulation (Petrinovic and Colombo Piñol, 2006;Acocella et al, 2011;Giordano et al, 2013;.…”

“…Due to the very low availability of rainwater in the area, the rivers, which normally have a permanent regime, are mostly associated with hot springs in their headwaters (Moya Ruiz, 1993;Paoli, 2003;Giordano et al, 2013Giordano et al, , 2016. The TGS is represented at surface by several hot springs with temperature up to 70.2 • C distributed in a small area (<0.4 km 2 ) along with Middle-Upper Pleistocene travertine deposits (<160 ka; Filipovich et al, 2020). Additionally, the Tocomar area shows evidence of hydrothermal alteration and sub-surface geothermal manifestations, such as phreatic and phreatomagmatic craters (Fig.…”

“…Additionally, the Tocomar area shows evidence of hydrothermal alteration and sub-surface geothermal manifestations, such as phreatic and phreatomagmatic craters (Fig. 1c) related to the TVC activity Giordano et al, 2013;Filipovich et al, 2020).…”

“…For this study, a holistic approach has been applied integrating available geological maps (e.g. Blasco et al, 1996;Petrinovic et al, 2010;Bonali et al, 2012;Giordano et al, 2013;Filipovich et al, 2020), published volcanological and structural data (e.g. Marrett et al, 1994;Petrinovic et al, 2005;2006;Bonali et al, 2012;Lanza et al, 2013;Norini et al, 2013), hydrologic and geochemical surveys (e.g.…”