The geological and structural evolution of the long-lived Miocene-Pleistocene La Hoyada Volcanic Complex in the geodynamic framework of the Central Andes, Argentina

Bustos, Emilce; Báez, Walter; Norini, Gianluca; Arnosio, Marcelo; Silva, De

doi:10.1016/j.jvolgeores.2018.07.010

Cited by 16 publications

(7 citation statements)

References 65 publications

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“…The La Hoyada volcanic complex is formed by several Miocene-Pleistocene, SW-NE-aligned, andesitic-dacitic composite volcanoes that form the San Buenaventura range (Fig. 1D; Seggiaro et al, 2000;Montero López et al, 2010a;Bustos et al, 2019). The San Buenaventura range was developed above a complex upper-crustal basement (Fig.…”

Section: Local Geological Settingmentioning

confidence: 99%

“…The volcanic stratigraphy of the La Hoyada volcanic complex is divided into two main units (Fig. 1D; Bustos et al, 2019): (1) Lower La Hoyada (ca. 7-4.6 Ma), comprising andesitic-dacitic lava flows and domes characterized by a pervasive tectonic deformation; and (2) Upper La Hoyada (4.6-1.3 Ma), mainly represented by andesitic-dacitic effusive products and subordinate pyroclastic and epiclastic deposits that form part of at least four volcanic edifices (stratovolcanoes and domes).…”

Section: Local Geological Settingmentioning

confidence: 99%

“…The Cerro Blanco volcanic complex (Fig. 2) represents a 15-km-wide, nested caldera cluster formed by several scarps with different topographical expressions and degrees of preservation, along with associated domes and pyroclastic deposits (Montero López et al, 2010a;Báez et al, 2015Báez et al, , 2017. It is the most recent stage of the La Hoyada volcanic complex and is built on top of Upper La Hoyada volcanic complex.…”

Section: Cerro Blanco Volcanic Complexmentioning

confidence: 99%

“…This phase was mainly effusive and produced several lava domes and block-and-ash-flow deposits emplaced in the southwestern caldera border (Arnosio et al, 2005;Montero López et al, 2009. The mechanisms of lava-dome growth and destruction have been addressed by Báez et al (2017). The postcaldera activity also included phreatomagmatic-phreatic small explosions (Montero López et al, 2010a;Báez et al, 2017a;Chiodi et al, 2019).…”

Section: Cerro Blanco Volcanic Complexmentioning

confidence: 99%

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Magmatic evolution and architecture of an arc-related, rhyolitic caldera complex: The late Pleistocene to Holocene Cerro Blanco volcanic complex, southern Puna, Argentina

et al. 2022

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Through the lens of bulk-rock and matrix glass geochemistry, we investigated the magmatic evolution and pre-eruptive architecture of the siliceous magma complex beneath the Cerro Blanco volcanic complex, a Crater Lake–type caldera complex in the southern Puna Plateau of the Central Andes of Argentina. The Cerro Blanco volcanic complex has been the site of two caldera-forming eruptions with volcanic explosivity index (VEI) 6+ that emplaced the ca. 54 ka Campo Piedra Pomez ignimbrite and the ca. 4.2 ka Cerro Blanco ignimbrite. As such, it is the most productive recent explosive volcano in the Central Andes. The most recent eruptions (younger than 4.2 ka) are dominantly postcaldera effusions of crystal-rich domes and associated small explosive pulses. Previous work has demonstrated that andesitic recharge of and mixing with rhyolitic magma occurred at the base of the magma complex, at ~10 km depth. New isotopic data (Sr, Nd, Pb, and O) confirm that the Cerro Blanco volcanic complex rhyolite suite is part of a regional southern Puna, arc-related ignimbrite group. The suite defines a tight group of consanguineous siliceous magmas that serves as a model for the evolution of arc-related, caldera-forming silicic magma systems in the region and elsewhere. These data indicate that the rhyolites originated through limited assimilation of and mixing with upper-crustal lithologies by regional basaltic andesite parent materials, followed by extensive fractional crystallization. Least squares models of major elements in tandem with Rayleigh fractionation models for trace elements reveal that the internal variations among the rhyolites through time can be derived by extensive fractionation of a quartz–two feldspar (granitic minimum) assemblage with limited assimilation. The rare earth element character of local volumes of melt in some samples of the Campo Piedra Pomez ignimbrite basal fallout requires significant fractionation of amphibole. The distinctive major- and trace-element characteristics of bulk rock and matrix of the Campo Piedra Pomez and Cerro Blanco tephras provide useful geochemical fingerprints to facilitate regional tephrochronology. Available data indicate that rhyolites from other neighborhood centers, such as Cueros de Purulla, share bulk chemical characteristics with the Campo Piedra Pomez ignimbrite rhyolites, but they appear to be isotopically distinct. Pre-eruptive storage and final equilibration of the rhyolitic melts were estimated from matrix glass compositions projected onto the haplogranitic system (quartz-albite-orthoclase-H2O) and using rhyolite-MELTS models. These revealed equilibration pressures between 360 and 60 MPa (~10–2 km depth) with lowest pressures in the Holocene eruptions. Model temperatures for the suite ranged from 695 to 790 °C. Integrated together, our results reveal that the Cerro Blanco volcanic complex is a steady-state (low-magmatic-flux), arc-related complex, standing in contrast to the flare-up (high-magmatic-flux) supervolcanoes that dominate the Neogene volcanic stratigraphy. The silicic magmas of the Cerro Blanco volcanic complex were derived more directly from mafic and intermediate precursors through extensive fractional crystallization, albeit with some mixing and assimilation of local basement. Geochemical models and pressure-temperature estimates indicate that significant volumes of remnant cumulates of felsic and intermediate composition should dominate the polybaric magma complex beneath the Cerro Blanco volcanic complex, which gradually shallowed through time. Evolution to the most silicic compositions and final equilibration of some of the postcaldera domes occurred during ascent and decompression at depths less than 2 km. Our work connotes an incrementally accumulated (over at least 54 k.y.), upper-crustal pluton beneath the Cerro Blanco volcanic complex between 2 and 10 km depth. The composition of this pluton is predicted to be dominantly granitic, with deeper parts being granodioritic to tonalitic. The progressive solidification and eventual contraction of the magma complex may account for the decades of deflation that has characterized Cerro Blanco. The presently active geothermal anomaly and hydrothermal springs indicate the Cerro Blanco volcanic complex remains potentially active.

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Section: Local Geological Settingmentioning

confidence: 99%

Section: Local Geological Settingmentioning

confidence: 99%

Section: Cerro Blanco Volcanic Complexmentioning

confidence: 99%

Section: Cerro Blanco Volcanic Complexmentioning

confidence: 99%

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Magmatic evolution and architecture of an arc-related, rhyolitic caldera complex: The late Pleistocene to Holocene Cerro Blanco volcanic complex, southern Puna, Argentina

et al. 2022

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“…Pleistocene volcanic sequence consisting of several andesitic-dacitic stratovolcanoes aligned in a SW-NE direction (La Hoyada Volcanic Complex, LHVC), which constitutes the San Buenaventura range (Seggiaro et al, 2000;Montero López et al, 2010;Bustos et al, 2019). CBVC stratigraphy consists of two main ignimbrite units separated by major unconformities that represent periods of quiescent volcanic activity (Báez et al, 2015).…”

Section: Geological and Volcanological Featuresmentioning

confidence: 99%

Preliminary conceptual model of the Cerro Blanco caldera-hosted geothermal system (Southern Puna, Argentina): Inferences from geochemical investigations

Chiodi

Tassi

Báez

et al. 2019

Journal of South American Earth Sciences

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The Cerro Blanco Caldera (CBC) is the youngest collapse caldera system in the Southern Central Andes (Southern Puna, Argentina). The CBC is subsiding with at an average velocity of 0.87 cm/year and hosts an active geothermal system. A geochemical characterization of emitted fluids was carried out based on the chemical and isotopic compositions of fumaroles, and thermal and cold springs discharged in this volcanic area with the aim of constructing the first hydrogeochemical conceptual model and preliminary estimate the geothermal potential. The main hydrothermal reservoir, likely hosted within the pre-caldera basement rocks, has a Na +-Clˉ(HCO 3)c omposition with estimated temperatures ≥135°C. The unconsolidated, fine-grained Cerro Blanco ignimbrite likely acts as the cap-rock of the hydrothermal system. The presence of phreatic eruption breccias in the surrounding area of the geothermal fumaroles supports the effectiveness of the pyroclastic deposit as sealing rocks. The isotopic data of water (δ 18 O and δD) indicate a meteoric recharge of the hydrothermal reservoir, suggesting as recharge areas the sectors surrounding the CBC, mainly towards the W and NW where large outcrops of the pre-caldera basement exist. A fault-controlled hydraulic connection between the hot springs and the hydrothermal reservoir is proposed for the Los Hornitos area. The fumaroles show the typical compositional features of hydrothermal fluids, being dominated by water vapor with significant concentrations of H 2 S, CH 4 and H 2. Considering the high geothermal gradient of this area (∼104°C/km) and the relatively high fraction of mantle He (∼39%) calculated on the basis of the measured R/Ra values, the hydrothermal aquifer likely receives inputs of magmatic fluids from the degassing magma chamber. The preliminary geothermal potential at CBC was evaluated with the Volume Method, calculating up to E = 11.4*10 18 J. Both the scarce presence of superficial thermal manifestations and the occurrence of an efficient cap-rock likely contribute to minimize the loss of thermal energy from the reservoir. The results here presented constitute the necessary base of knowledge for further accurate assessment of the geothermal potential and ultimately the implementation of the geothermal resource as a viable energy alternative for small localities or mining facilities isolated from the National Interconnected System due to their remote localization.

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Genesis of megaspherulites in El Viejo Rhyolitic Coulee (Pleistocene), Southern Puna, Argentina

et al. 2020

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The geological and structural evolution of the long-lived Miocene-Pleistocene La Hoyada Volcanic Complex in the geodynamic framework of the Central Andes, Argentina

Cited by 16 publications

References 65 publications

Magmatic evolution and architecture of an arc-related, rhyolitic caldera complex: The late Pleistocene to Holocene Cerro Blanco volcanic complex, southern Puna, Argentina

Magmatic evolution and architecture of an arc-related, rhyolitic caldera complex: The late Pleistocene to Holocene Cerro Blanco volcanic complex, southern Puna, Argentina

Preliminary conceptual model of the Cerro Blanco caldera-hosted geothermal system (Southern Puna, Argentina): Inferences from geochemical investigations

Genesis of megaspherulites in El Viejo Rhyolitic Coulee (Pleistocene), Southern Puna, Argentina

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