Andres Folguera

• Dr
• Professor at National Scientific and Technical Research Council-Facultad de Ciencis Exactas y Naturales, Universidad de Buenos Aires

This research covers the study of the first month of data from a local seismological network deployed after the MW 6.4, January 18, 2021, San Juan earthquake, over the central Chilean-Pampean flat slab. Almost 1000 seismic events were detected in the first month after the MW 6.4 earthquake occurred, with ML magnitude ranging from −0.2 to 4.3. The m...

Plio-Pleistocene magmatism in the Southern Central Andes (34-38 °S) developed contemporaneously with inferred steepening and destabilization of the subducted Nazca plate associated with a slab tearing at 38°S. Within this setting, arc-related magmatic activity developed in N-S striking belts. Particularly, the studied Varvarco Volcanic Field (VVF)...

A paleomagnetic study of basaltic lava flows exposed in the northern Neuquén Cordillera, southernmost Central Andes, along the Antiñir-Copahue fault zone (ACFZ), involved 25 sites of the Cola de Zorro Formation (Pliocene–Early Pleistocene) along two different sections. The sites show exclusive normal polarity, corresponding to the Late Pliocene Gau...

El cerro Sosneado (34°45 ́30”S - 69°58 ́14”O) comprende un estratovolcán de 5.189 m.s.n.m de edad plio-pleistocena ubicado cerca de las nacientes del río Atuel, al este de la Cordillera Principal de Mendoza (Figs. 1a, b, c). Forma parte de un conjunto de centros eruptivos localizados en una posición de tras-arco, entre el actual arco volcánico y el...

Geoquímica y Geocronología del Complejo Volcánico Aconcagua (33°S),. Andes Centrales del Sur

Durante el Pleistoceno-Holoceno, en los Andes Centrales del Sur, tuvo lugar un importante período glaciar concomitante con un período de intenso vulcanismo. De esta manera, los glaciares habrían estado circundando los principales edificios volcánicos activos en ese tiempo, lo que sugiere que debió existir una interacción entre ellos. A partir de nu...

En este artículo se analiza el depocentro Alto Atuel ubicado en el margen noroccidental de la Cuenca Neuquina. Los estudios se focalizaron en las sucesiones volcano-sedimentarias jurásicas aflorantes en las nacientes del río Atuel, las cuales han sido poco estudiadas a lo largo del tiempo. Este depocentro, localizado a los 34°35’S y 70°10’O, result...

Located in a poorly studied zone of the rear arc in the Transitional Southern Volcanic Zone, the Overo volcano presents a complete record of syn-glacial, inter-glacial, and post-glacial activity, marked by significant changes in eruptive mechanisms over time. Following pre-glacial units, an effusive syn-glacial basaltic phase was succeeded by an ex...

The late Eocene to earliest Miocene volcanic arc of the Southern Central Andes (33-40°S) and North Patagonian Andes (40-44°S) exhibits distinctive features that shed light on the dynamics of subduction-related volcanic activity in extensional tectonic settings. This period is particularly significant in the Andes, as it records the opening of forea...

The early stages of Andean construction have been barely recognized due to a long history of tectonic superposition during the growth of the orogen. In this work, we present a multi‐method approach integrating sedimentological, geochronological, structural, and provenance analyses to reconstruct the architecture of the Late Cretaceous foreland basi...

The article is accesible in the page of AJS with the doi number. ABSTRACT. The south-central Chile and Argentina margin experienced a regional phase of extensional tectonics during the Oligocene-early Miocene, forming several basins across the forearc, Andean Cordillera, and retroarc regions. These basins accumulated thick successions of volcanic...

Many studies propose a significant shift in the tectonic and paleogeographic evolution of the Andes in south-central Chile and Argentina during the Late Cretaceous. It has been proposed that the preceding Jurassic-Early Cretaceous extensional regime that resulted in a low-relief volcanic arc and the backarc Neuquén basin came to an end, giving way...

In recent years, multiple Mesozoic episodes of crustal shortening and extension have been documented throughout Patagonia. These findings unveil a complex history of regional intraplate tectonic deformation. Nevertheless, there are numerous sectors in this vast region that have yet to undergo in-depth tectonic investigations, and hence aspects of i...

Continental arcs are associated with volcanism concentrated into two main belts—the main arc and back arc, often separated by fold and thrust belts. The Loicas Trough, Argentina, is a post-orogenic extensional feature that obliquely cuts the fold and thrust belts. The trough hosts large Pliocene–Holocene volcanic centres, including Domuyo and Trome...

The Indiana Deposit corresponds to a Cu–Au (Mo–Co) fault-vein deposit located in the Central Andes Coastal Cordillera Belt (∼27°S). It is hosted by strongly altered volcanic and intrusive rocks located between the NNE–striking central and principal branches of the Atacama Fault System (AFS) in northern Chile. The Indiana Deposit is part of a 10 km-...

The Aconcagua region constitutes a classical site to study the growth of the Andes, being host of the highest mountain of South America and focus of numerous investigations since its first description by Charles Darwin almost 200 years ago. The last detailed works in this area characterized it as a typical thin-skinned fold-thrust belt with a basal...

The Southern Central Andes developed though a complex succession of magmatic and deformational episodes, which after more than a century of studies, are still the subject of intense debate. One of the main controversies lies in the ambiguity regarding whether there was a single contractional phase in the Neogene or whether there were multiple contr...

Andean broken foreland zones, located to the east of the highest Andes, are associated with populated areas and sedimentary basins with relative economic importance. Understanding their seismogenic potential is crucial for urban development and infrastructure planning. In particular, the San Rafael Block is part of the broken foreland developed to...

The Salinas Grandes and Salina de Ambargasta salt pans are located in the Eastern Sierras Pampeanas in the Pampean broken foreland zone, a product of the Chilean-Pampean flat subduction zone. This region constitutes an anomalously flat morphology of 350 x 150 km and occupies an extensive area in a northeast-southwest direction. These flat depressio...

The Middle Jurassic‐Early Cretaceous evolution of the Neuquén Basin is traditionally attributed to a long phase of thermal subsidence. However, recent works have challenged this model. In view of this, we study the Late Jurassic Tordillo Formation, a nonmarine depositional unit that marks a shift to regional regression across the basin. Previous st...

Over the past decade, the three largest and most destructive earthquakes in recent history with associated tsunamis occurred: the Mw = 9.2 Sumatra-Andamam in 2004, then the Mw = 8.8 Maule in 2010, and finally the Mw = 9.1 Tohoku- Oki in 2011. Due to the technological and scientific developments achieved in recent decades, it has been possible to st...

Los primates platirrinos constituyen un grupo ecológicamente importante en la Región Neotropical, pero su registro fósil es notorio por su escasez. En Chile, se conocen solo tres fósiles neógenos: el cráneo de Chilecebus de Río Las Leñas (SGO.PV.3213), un astrágalo de Río Cisnes (SGO.PV.974), y un diente aislado de Lonquimay (SGO.PV.22204). Aquí pr...

At the southern Pampean flat-slab, the Quaternary active deformation is concentrated on the easternmost thrusts of the Southern Precordillera along the Las Peñas-Las Higueras hill (32° 10’-32° 45’). This range is bounded by Las Peñas thrust, which emplaces Cenozoic sedimentary rocks over a suite of Quaternary alluvial deposits. The Neogene mountain...

At the southern Pampean flat-slab, Quaternary active deformation is concentrated on the easternmost thrusts of the Southern Precordillera along the Las Peñas-Las Higueras range (32° 10'-32° 45'S). The Las Peñas thrust bounds this range and propagates in the piedmont through splays successively incorporated into the hanging wall. At the southern ran...

The Río Damas Formation is an Upper Jurassic volcano-sedimentary succession, whose outcrops are largely distributed between 33°S and 35.30°S in Chile and Argentina, as part of the retroarc Neuquén Basin fill. This unit was deposited during an important marine regressive phase of the basin. We studied the Río Damas Formation exposures at the Los Gat...

This Editorial is based on the recent advances presented in the Special Issues related to tectonics across South America, released in the last three years. Its objective is to display the intense work focused on different lines of research of the Andean and Pre-Andean tectonic field and also to summarize key aspects extracted from these volumes in...

We conducted a U–Pb–Hf isotope study on zircon crystals from ignimbrites of the Changhsingian to Olenekian (253–248 Ma) Los Menucos Basin in the North Patagonian Massif (NPM), Argentina, in order to evaluate the age and petrogenesis of the magmas. Additionally, a compilation of whole-rock geochemistry and U–Pb–Hf in zircon isotope data for the Perm...

Andean orogenesis is expressed in the diverse deformational records of crustal structures and sedimentary basins in western South America. Here we summarize retroarc structural styles within the Andean orogenic belt and foreland basin system through consideration of regional contractional fault geometries, their kinematic interactions with other st...

The volcanic complex of Nevados de Chillán, located in the Southern Volcanic Zone (SVZ) of the Andes, has been active for the past 640 ± 20 ka. Its volcanic activity includes dome forming eruptions, explosive events, and lava flows. The most recent eruption cycle started in January 2016. We employ DInSAR time-series from Sentinel-1 data to investig...

Los Andes Norpatagónicos se extienden entre ~40-47°S como un sistema orogénico de anatomía moderada, es decir, con una cordillera principal de valores relativamente bajos de topografía, ancho y espesor cortical. Este segmento Andino está compuesto casi exclusivamente por rocas ígneas mesozoicas que forman una asociación de arco continental: el Bato...

El presente trabajo tiene como objetivo el estudio del volcanismo cenozoico tardío en los Andes Centrales del Sur (32-33°S), en el límite sur del segmento de subducción horizontal pampeano-chileno. El mismo se enfoca en el volcanismo expuesto en el sector norte de la Faja Plegada y Corrida del Aconcagua, más precisamente en las nacientes del río Bl...

The Argentine Andes between 34° and 36°S comprise a region that lies immediately south of the transition from the Chilean-Pampean flat-slab to a normal subduction segment. Several key changes take part through this area, such as a westward shift of the magmatic arc front, the end of Paleozoic outcrops of the Frontal Cordillera denoting a decline in...

The Neogene Penitentes basin registers the earliest synorogenic infill in an inner region of the southern Central Andes, between Principal and Frontal cordilleras at 33°S, which contrast with other Neogene basins that are distributed to the east, in the foreland area. In this work, we focused on the study of the first infill of the basin, the Penit...

Orogenic belts like the Andes experience several changes during long-term evolution of the subduction margin; however, the degree to which their different components (the fore-to-retroarc domains) are jointly or separately deformed is not well understood. To investigate this problem, we provide new field and seismic data of the Chilean forearc at t...

The Bajo Grande area is located in the central sector of the Deseado Massif, in the Santa Cruz province of Argentina. In this area, there are outcrops of the Bahía Laura Volcanic Complex (BLVC) that include the Bajo Pobre, Chon-Aike and La Matilde formations, as well as the Bajo Grande Formation and the Baqueró Group (Panza et al. 2001). Several st...

The Upper Triassic magmatic and tectonic evolution of the central North Patagonian Massif is evaluated on the basis of the zircon U–Pb-Hf record and whole-rock geochemistry for volcanic rocks of the Los Menucos area. The sample analyzed on this study yields a 210 ± 3 Ma U–Pb zircon age, and the geochemical data for the Upper Triassic rocks are indi...

El presente trabajo tiene como objetivo el estudio del volcanismo cenozoico tardío en los Andes Centrales del Sur (32-33°S), en el límite sur del segmento de subducción horizontal pampeano-chileno. El trabajo se enfoca en el volcanismo expuesto en la región de la Faja Plegada y Corrida del Aconcagua, particularmente en el límite internacional con C...

El presente trabajo tiene como objetivo el estudio del volcanismo cenozoico tardío en los Andes Centrales del Sur (32-33°S), en el límite sur del segmento de subducción horizontal pampeano-chileno. El trabajo se enfoca en el volcanismo expuesto en la región de la Faja Plegada y Corrida del Aconcagua, particularmente en el límite internacional con C...

El presente trabajo tiene como objetivo el estudio del volcanismo cenozoico tardío en los Andes Centrales del Sur (32-33°S), en el límite sur del segmento de subducción horizontal pampeano-chileno. El trabajo se enfoca en el volcanismo expuesto en la región de la Faja Plegada y Corrida del Aconcagua, particularmente en el límite internacional con C...

El presente trabajo tiene como objetivo el estudio del volcanismo cenozoico tardío en los Andes Centrales del Sur (32-33°S), en el límite sur del segmento de subducción horizontal pampeano-chileno. El trabajo se enfoca en el volcanismo expuesto en la región de la Faja Plegada y Corrida del Aconcagua, particularmente en el límite internacional con C...

The Guañacos fold and thrust belt, in the northern Neuquén Andes (37°-38°S; 70°30′-71°10′W), has been studied by many researchers focusing on the Quaternary tectonic activity, from a morphological to a structural perspective. Additionally, this portion of the Andes is quite peculiar due to the numerous geomorphic processes coeval with neotectonic,...

Editor: Augusto Rapalini RESUMEN La fosa de Loncopué es una cuenca extensional del Plioceno al Cuaternario producida por la reactivación extensional del área del intrapaís de los Andes Centrales del Sur. Los estudios previos que se han realizado en esta zona se han centrado en su relleno vol-cán-sedimentario, estructura superficial y actividad neot...

During the last two decades, space geodesy allowed mapping accurately rupture areas, slip distribution, and seismic coupling by obtaining refined inversion models and greatly improving the study of great megathrust earthquakes. A better understanding of these phenomena involving large areas of hundreds of square kilometers came from the last gravit...

A set of fracture zones left by transform faults segmenting the active Chile Ridge that separates the Nazca and Antarctica Plates has been subducting beneath western Patagonia in the last 18 Myr. The subduction direction of these fractures zones has remained almost unaltered during this time lapse since these intersected the Chilean trench. In this...

El antepaís fragmentado Patagónico agrupa a una serie de serranías ubicadas en la región extraandina y constituye una de las múltiples unidades morfoestructurales de intraplaca de Sudamérica. Si bien varios aspectos del antepaís fragmentado Patagónico permanecen aún en discusión, se ha avanzado significativamente en el entendimiento de esta región...

We present a study about the San Juan Mining District hosted in the Paleozoic basement in Atacama Region. In this paper, we propose two hypotheses about the deformation and mineralization. The first hypothesis is that Cu-Co (Au) mineralization has an upper Jurassic age, coeval to the Jurassic intrusives and hydrothermal processes, controlled along...

Two compositionally different volcanic cycles are documented by geological mapping, lithofacies and petrographic analyses of Jurassic volcanic rocks in the northeastern sector of the Deseado Massif, constituting the western counterpart of the Karoo-Ferrar LIPs in Patagonia. The first cycle is of intermediate composition and is represented by andesi...

Resumen La evolución tectónica del continente sudamericano puede resumirse en dos etapas principales: 1) La etapa cratónica del Precámbrico, en la cual las masas continentales que componen el centro y oeste de Sudamérica (Amazonia, Rio de la Plata y San Francisco) se reunieron para formar parte de varios supercontinentes como Columbia y Rodinia. La...

The early Mesozoic extensional processes recognized in SW Gondwana have been related to a supercontinent precursor break-up phase, the gravitational collapse of a late Paleozoic orogen, changes in subduction dynamics or the impact of a thermal anomaly. However, intraplate extension is still lacking accurate temporal constraints for the area devoid...

The Río de la Plata estuarine has been the epicenter of the 30 November 2018 intra-crustal earthquake with a magnitude and focal depth of 3.7 and 19 km (±6 km), respectively, which alerted the Buenos Aires city population. This area has also been the locus of a series of earthquakes with magnitudes ranging from 3.7 to 5, and particularly the 1888 e...

During Mid-Cenozoic times, voluminous and genetically heterogeneous volcanism took place across North Patagonia in response to a period of plate tectonic reorganization. One of these volcanic associations is represented by the El Maitén Belt, located to the east of the main Andes for over ∼300 km. This volcanic belt reflects the evolution of a cont...

Since the initial proposal of the past existence of a southward-directed mid-ocean ridge–subduction interaction in the Andes during Late Cretaceous–Paleogene times, several studies have been devoted to uncover the tectonomagmatic evidence of this process. The collision of a spreading ridge against a subduction margin provokes important tectonomagma...

Geochemical variations in arc- and within-plate magmatic associations since Late Cretaceous times are analyzed and correlated with the main tectonic changes that influenced the Neuquén Basin evolution. The collision and southward migration of the Farallon-Aluk mid-ocean ridge along the Chilean trench since 80 Ma have played an important role in con...

The first regional tectonic uplift was registered in the Neuquén Basin at ca. 100 Ma, resulting in the inception of the first foreland basin of the Andes at these latitudes. The infill of this foreland basin is represented by the nonmarine deposits of the Neuquén Group, characterized by the presence of growth strata and fold-thrust belt detrital de...

At the northwestern Mendoza province, the Mesozoic infill of the Neuquén Basin is tectonically repeated in the Aconcagua fold-and-thrust belt. Particularly, the Tordillo Formation (commonly associated with the Kimmeridgian) represents a local low stand period of sea level, with mainly alluvial and fluvial sediments. Toward the western sector of the...

The Loncopué Trough is an extensional basin produced by the extensional reactivation of the hinterland area of the Southern Central Andes. Neotectonic extensional structures in this basin bound a broad topographic low filled with volcanic and volcaniclastic rocks. The studies carried out in the area of the Loncopué Trough have concentrated on the s...

The tectonic regime associated with the Oligo-Miocene Cura-Mallín Formation and equivalents in the Main Andean Cordillera between 35° and 40° S, the Ventana and Abanico formations to the south and north, respectively, is still matter of debate. While most authors have agreed in relating them to an extensional regime that could have interrupted Ande...

Geological observations in the Neuquén Basin indicate a Late Oligocene to Early Miocene episode of extension followed by an abrupt shift towards regional compression. However, the reasons behind this brief extensional episode and the Oligo-Miocene tectonic mode switch are not fully understood. Through the aid of numerical modelling, it has been sho...

The occurrence of a Neogene shallow subduction stage, as well as, a Pliocene slab-tearing, and steepening of the Nazca plate in the southern Central Andes are well established. However, a satisfactory explanation for the origin and connection between these complex processes is still elusive. In this contribution, we revise the late Cenozoic tectoni...

Late Oligocene to Pliocene magmatism at the latitudes of Malargüe and Chos Malal fold and thrust belts, in the Neuquén Basin, is distributed from the main Andean axis to the retroarc zone. While arc magmatism maintained relatively similar compositional and geochemical features during late Oligocene to Pliocene times, major variations are seen in vo...

Quaternary deformations described in the retro-arc region at the latitudes of the Neuquén Basin can be divided into two main groups: a northern group characterized by Quaternary deformation zones concentrated near the main topographic breaks of different morphostructural systems, and a second group located in the southern Neuquén Basin distinguishe...

The Cretaceous-Cenozoic evolution of the Patagonian broken foreland basin system at 42–43°S in the northern Chubut province of Argentina is associated with variable retroarc phases of fold-thrust belt shortening, extension, and basement uplift during changes in the dynamics of oceanic slab subduction. Basement inheritance and progressive shallowing...

This book provides an overview of newly gathered material focusing on the opening and closure of The Neuquén Basin. The Neuquén Basin contains the most important hydrocarbon reservoirs in Argentina and therefore is characterized by a profound knowledge of the sedimentation mechanisms and closure times. During the last 10 years a considerable amount...

Geochemical and geochronological data reveal that late Oligocene‐early Miocene time is a break point in the evolution of Andean magmatism. The Patagonian Andes registered the onset of arc volcanism since the late Eocene forming part of the El Maitén Belt, whose development was driven by the subduction of the Farallon/Nazca plates beneath the Andean...

The Patagonian Andes are characterized by a high relief, with numerous confined lakes in deep glacial valleys that currently experience minor rock falls. Although, there is a poorly known historical and post-glacial register of mass wasting phenomena and a complete absence of monitoring for potential future processes. In particular, the area called...

The Andes constitute an ideal tectonic setting for investigating different modes of subduction orogeny, given its segmented anatomy and the potential drivers of the upper/lower plates over the episodic periods of mountain building (e.g., Mpodozis and Ramos, 1989). In this sense, integrated analyses of orogenic sections that contemplate from the for...

The Cura Mallín Fm comprises Oligo-Miocene (24-12 Ma) volcanosedimentary rocks covering the axis of the Southern Central Andes of Argentina and Chile (36°-39°S). The tectonic mechanism for deposition of this unit is still matter of debate. There are two contradictory proposals: while some authors have proposed an extensional regime (Jordan et al. 2...

Geología de la Región del Lago Traful: implicancias en la generación de procesos de remoción en masa y su potencial riesgo geológico

New volcanic unrest has been detected in the Domuyo Volcanic Center (DVC), to the east of the Andes Southern Volcanic Zone in Argentina. To better understand this activity, we investigated new seismic monitoring data, gravimetric and magnetic campaign data, and interferometric synthetic aperture radar (InSAR) deformation maps, and we derived an ima...