Journal of South American Earth Sciences最新文献

{"title":"A review of 100 years of paleontological research in the Highest Andes","authors":"Beatriz Aguirre-Urreta","doi":"10.1016/j.jsames.2025.105902","DOIUrl":"10.1016/j.jsames.2025.105902","url":null,"abstract":"<div><div>This research describes the earliest paleontological reports from the High Andes of Argentina and Chile, dating back to the mid-19th and early 20th centuries. They were largely based on observations made during geological and exploratory expeditions. These investigations are ordered chronologically, and although often limited by logistical challenges, documented the presence of marine Mesozoic invertebrate fossils from strata exposed at high altitudes. The first records are due to John Gillies, and not to Joseph Pentland as said for many years, though their importance was unfortunately ignored. Franz Meyen and Charles Darwin deserve a central place among the earliest naturalists who contributed to the paleontology of the region. Following those pioneering observations, Alfred Stelzner played a key role in the second half of the 19th century by integrating paleontological data into regional geological mapping. A generation later, Walther Schiller, carried out some of the most systematic paleontological and stratigraphic investigations of the High Andes where he correlated marine fossil assemblages with tectonic structures.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105902"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking mineralogical facies, petrophysical properties, and non-matrix features in silicified carbonates, BM-C-33, Campos Basin","authors":"Michele Iemma,&nbsp;Vinicius Carneiro,&nbsp;André Gondim Brandão,&nbsp;João Paulo Oliveira,&nbsp;Leonardo Borghi","doi":"10.1016/j.jsames.2025.105921","DOIUrl":"10.1016/j.jsames.2025.105921","url":null,"abstract":"<div><div>In the distal southern Campos Basin, the reservoirs consist of pre-salt carbonates (Macabu Fm.), which underwent successive diagenetic processes such as silicification and dolomitization. These processes are responsible for changing the original mineral composition as well as their pore system categorized into matrix and non-matrix features. Therefore, advanced techniques such as Artificial Intelligence (AI) and related methodologies have been increasingly applied to improve the prediction of reservoir characteristics. This study aims to use open-hole wireline logs and borehole image logs (BHI) from six wells in the BM-C-33 block to investigate the distribution of non-matrix features and permeability–porosity properties, across mineralogical (calcite, dolomite, silica and clay) and reservoir facies of the Macabu Formation carbonates. The study's findings reveal a notable prevalence of silicified carbonates interbedded with restricted dolomitized layers. These highly silicified intervals exhibit a higher fracture density, with a mean P10 of around 3 fractures/m. Petrophysical models indicate average porosity and permeability values of 9 % and 0.34 mD, respectively among the six wells. The highest values occur in silicified carbonates, contrasting with the lower ones observed in dolomitized intervals. Overall the study suggest a certain favoring of the silicification process in the quality of the reservoirs.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105921"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Campanorco Subvolcanic Complex: Insights into Miocene back-arc magmatism and slab shallowing in the 24°–26°S segment of the Central Andes","authors":"Guadalupe Maro ,&nbsp;Juan Pablo Villalba Ulberich ,&nbsp;Gabriel I. Alemán ,&nbsp;Alba C. Muñoz Dada ,&nbsp;Tai Wen ,&nbsp;Chao Zhang ,&nbsp;Patrocinio Flores ,&nbsp;Edgar D. González ,&nbsp;Pablo J. Caffe","doi":"10.1016/j.jsames.2025.105930","DOIUrl":"10.1016/j.jsames.2025.105930","url":null,"abstract":"<div><div>The Campanorco Subvolcanic Complex (25°38′S–65°33′W) is a poorly known unit that comprises pheno-andesitic sills and dikes located approximately 600 km east of the Nazca Plate subduction trench, an unusual setting for typical Andean back-arc magmatism. This contribution offers new petrographic, geochemical and geochronological data. U-Pb dating on zircon yielded crystallization ages of 6.8 Ma, confirming its belonging to Upper-Miocene back-arc magmatism. This igneous system consists of amphibole-bearing rocks of the high-K calc-alkaline and shoshonitic series, related to an enriched mantle source, likely metasomatized by subduction-derived fluids. Magmatic differentiation primarily occurred through fractional crystallization of water-rich parental magmas, with low crustal contamination, typical of steady-state andesites. Magmatic enclaves are widespread and are good physical evidence for the influence of multiple episodes of magma mixing on magma evolution.</div><div>The formation of the Campanorco Subvolcanic Complex is attributed to slab shallowing during Middle to Late Miocene times, likely driven by the subduction of the Taltal and Copiapó aseismic ridges, which facilitated mantle hydration and magma generation far from the volcanic arc. This unit serves as a key indicator of the maximum extent of slab shallowing during this period in the segment between 24° and 26°S. The study of this system provides critical insights into the petrogenesis, tectonic setting, and mineralization potential of the easternmost Neogene back-arc magmatism in the Central Andes.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105930"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Panoramic Transect of the Western Flank of Eastern Cordillera Fold and Thrust Belt, Northern Andes, Colombia","authors":"C. Montes ,&nbsp;C.A. Rosero ,&nbsp;F. Lamus ,&nbsp;L.C. Perez-Angel ,&nbsp;G. Bayona ,&nbsp;J.M. Muñoz","doi":"10.1016/j.jsames.2025.105918","DOIUrl":"10.1016/j.jsames.2025.105918","url":null,"abstract":"<div><div>A ∼23 km-long, hiking-kayaking, panoramic transect along the Rionegro Canyon in the western flank of the Eastern Cordillera of Colombia reveals two deformed belts with contrasting structural styles separated by a regional fault (La Salina Thrust). East of the fault, a deformed belt is characterized by tight, horizontal and upright concentric and box folds with pervasive axial-planar cleavage within a Lower Cretaceous, mostly sandy sequence. West the fault, the structural style is characterized by thrust sheets with prominent footwall deformation and isoclinal folding in the hanging wall. At least four stacked thrust sheets that repeat Upper Cretaceous sequences define a regional-scale duplex (El Trigo-Bituima anticlinal stack duplex). Immediately west of the anticlinal duplex, a regional syncline (Guaduas) folds a ∼1.5 km-thick, middle Eocene to Oligocene molasse deposit. The western flank of the syncline is thrusted (Cambras Thrust) on to a ∼2 km-thick Miocene molasse deposit repeated by the frontal thrust of the Eastern Cordillera (Honda Thrust). Line-balancing of a 30 km-long cross-section that includes the Honda Thrust results in a shortening value of ∼60 % (∼45 km) not considering layer-parallel shortening. Reconstruction of the original geometry suggests the presence of two rift-fault systems: one to the east, where the thickness of Cretaceous sequence changes from ∼4 to 3 km, and another one ∼50 km to the west, where the ∼3 km-thick Cretaceous sequence thins to nothing. The former is reactivated as the La Salina Thrust and likely contains pre-Cretaceous basement rocks in its hanging wall, and the latter is not reactivated, as previous studies had proposed. All of this is consistent with a main pulse of growth of the Eastern Cordillera and major surface elevation gain starting in middle Eocene times.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105918"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geological and volcanological constraints on a long-lived and multi-stage collapse caldera: The Caviahue caldera, southern volcanic zone of the Andes","authors":"I.A. Petrinovic ,&nbsp;I.R. Hernando ,&nbsp;J. Martí Molist","doi":"10.1016/j.jsames.2025.105922","DOIUrl":"10.1016/j.jsames.2025.105922","url":null,"abstract":"<div><div>The Caviahue caldera represents one of the largest topographic depressions identified in the Southern Volcanic Zone of the Andes. Here we present volcanological, stratigraphic, geochronological, and structural data of the Caviahue caldera, complemented by available subsurface information. These data support the interpretation of two caldera collapse cycles: the first at 1.27 Ma (Caviahue Caldera) and the second at 0.134 Ma (Las Mellizas Caldera). Both cycles are predominantly intermediate in composition and share several key features, including the formation of multiple lava vents, widespread deposition of ignimbrite and lava sheets associated with caldera collapse, and inter-eruptive epiclastic sedimentation. The 1.27 Ma Caviahue caldera did not result from a single, catastrophic collapse event, but from incremental collapses driven by substantial lava effusion episodes similar to those observed in mafic calderas, interspersed with explosive events characteristic of silicic systems.</div><div>The Las Mellizas caldera, dated at 0.134 Ma, began with pre-caldera lava flows and syn-to inter-eruptive sedimentation within deltaic, fluvial, and alluvial settings related to a glacial environment. This was followed by a single ignimbritic eruption accompanying caldera collapse, concluding with the growth of the post-caldera Copahue volcano.</div><div>Both caldera collapse cycles show evidence of interactions between effusive and explosive volcanism and glacial conditions, as recorded in both volcanic and sedimentary deposits. This indicates the presence and persistence of glaciations in the Southern Andes prior to 1.27 Ma. The pattern of incremental caldera collapse, characterized by both effusive and explosive activity within glaciated environments, may represent a defining feature of calderas in the Southern Volcanic Zone.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105922"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coprolites from the Romualdo Formation (Lower Cretaceous, Araripe Basin, Brazil): brief comments on morphology and trophic interactions","authors":"Maria Aline Pereira Dino ,&nbsp;Rafael César Lima Pedroso de Andrade ,&nbsp;Naiara Cipriano Oliveira ,&nbsp;Fábio Hideki Yamada ,&nbsp;Antônio Álamo Feitosa Saraiva ,&nbsp;Renan Alfredo Machado Bantim","doi":"10.1016/j.jsames.2025.105931","DOIUrl":"10.1016/j.jsames.2025.105931","url":null,"abstract":"<div><div>Coprolites can provide clues about the diet and behavior of extinct organisms. We investigated 66 coprolites from the Romualdo Formation (Lower Cretaceous, Araripe Basin, Brazil), housed in the paleontological collection of the Paleontology Laboratory of the Universidade Regional do Cariri (LPU). All specimens were collected over the last decade at the Café das Antigas site (Lameiro district, Crato, Ceará), a locality that exposes laminated carbonates, carbonatic concretions, and shales of the Romualdo Formation and has yielded a diverse assemblage of vertebrate and plant remains. Using stereomicroscopy and morphometric documentation, we classified specimens into diagnostic morphotypes following previous established criteria, based on end morphology (isopolar and anisopolar) and overall outline. Five morphotypes were identified, such as cylindrical (n = 16), conical (n = 5), spiral (n = 3), ovoid (n = 14), and amorphous/irregular (n = 2), in addition to 26 indeterminate specimens. Seven coprolites (10.6 %) preserve expressive phosphatic fragments consistent with fish bones and scales, adding independent ichnological evidence that complements body-fossil evidence that teleosts were one of the main producers. Rare spiral forms may relate to fish with a spiral valve. These observations are constrained by the low proportions of inclusions and the descriptive scope of our analyses. We highlight the value of coprolites for reconstructing trophic interactions in this Konservat-Lagerstätte and outline avenues for future work to refine producer identification and detect microinclusions.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"171 ","pages":"Article 105931"},"PeriodicalIF":1.5,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress regime of Colombia from seismological tensor inversion","authors":"Olga Bohórquez-Orozco ,&nbsp;Jhon Restrepo-Berrío ,&nbsp;Héctor Mora-Páez","doi":"10.1016/j.jsames.2025.105894","DOIUrl":"10.1016/j.jsames.2025.105894","url":null,"abstract":"<div><div>This study characterizes the present-day stress field of northwestern SouthAmerica using 337 focal mechanism solutions compiled from the Colombian Seismological Network, USGS, GEOFON, and GCMT catalogues. Based on seismicity depth, geographic proximity, and tectonic context, 30 stress regions were delineated, and their corresponding stress tensors were determined. The results reveal that compressional regimes dominate north of 5° N, where the maximum horizontal stress (SHmax) trends NW–SE, controlled by the convergence between the Panama–Choco Block and the North Andean Block. Southward, the regime transitions to strike-slip faulting with E–W-oriented SHmax, associated with right-lateral and conjugate fault systems. Along the Nazca Plate subduction front, pre-trench extensional regimes evolve into post-trench compressional settings within the accretionary prism. Intermediate-depth tensors in the Cauca and Bucaramanga sectors reveal an in-slab extensional axis for the former and NW–SE compression for the latter, where seismicity patterns support the presence of a detached Paleo-Caribbean slab. The stress tensor distribution confirms that the Panama–Choco–North Andean boundary is structurally complex, while the Eastern and Central Cordilleras display second-order transpressive regimes consistent with major crustal-scale faults.</div></div><div><div>Este estudio caracteriza el campo de esfuerzos actual de la esquina noroccidental de Suramérica, utilizando 337 soluciones de mecanismos focales compiladas de los catálogos de la Red Sismológica Nacional de Colombia, USGS, GEOFON y GCMT. Con base en la profundidad de la sismicidad, la proximidad geográfica y el contexto tectónico, se delimitaron 30 regiones de esfuerzo y se determinaron sus respectivos tensores. Los resultados revelan que los regímenes compresivos dominan al norte de los 5° N, donde el esfuerzo horizontal máximo (SHmax) tiene una orientación NW–SE, controlada por la convergencia entre el Bloque Panamá–Chocó y el Bloque Norandino. Hacia el sur, el régimen transiciona a fallamiento de tipo transcurrente con SHmax orientado E–O, asociado a sistemas de fallas dextrales y conjugadas. A lo largo del frente de subducción de la Placa de Nazca, los regímenes extensionales pre-fosa evolucionan hacia configuraciones compresivas pos-fosa dentro del prisma de acreción. Los tensores de profundidad intermedia en los sectores de Cauca y Bucaramanga revelan un eje extensional dentro de la losa para el primero y compresión NW–SE para el segundo, donde los patrones de sismicidad respaldan la presencia de una paleolosa Caribe desprendida. La distribución de los tensores de esfuerzo confirma que el límite entre los bloques Panamá–Chocó y Norandino es estructuralmente complejo, mientras que las cordilleras Oriental y Central exhiben regímenes transpresivos de segundo orden coherentes con fallas corticales de gran escala.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"170 ","pages":"Article 105894"},"PeriodicalIF":1.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeochemical controls on thermal springs around Villarrica volcano","authors":"Claudia Bucarey Parra ,&nbsp;Joaquin Llano ,&nbsp;Mariano Agusto ,&nbsp;Gabriela Velásquez Vargas","doi":"10.1016/j.jsames.2025.105879","DOIUrl":"10.1016/j.jsames.2025.105879","url":null,"abstract":"<div><div>Villarrica volcano is one of the most extensively studied active volcanic systems in the South American Andean range. However, the linkage between the volcano and its surrounding thermal waters remains poorly understood. In this study, we present a comprehensive geochemical investigation based on 52 samples of water and 9 dissolved gas samples collected from 18 sites during three field campaigns. Integrated analyses of physicochemical parameters, major ion species, minor elements, stable isotope ratios, and gas compositions have allowed us to identify and differentiate distinct hydrofacies. Our findings reveal that water-rock interaction, principally through plagioclase dissolution leading to Na enrichment, is the predominant process controlling the hydrochemistry. Furthermore, while the aquifers are heated by a deep magmatic reservoir and by the regional geothermal gradient, interactions with ascending hydrothermal gases are critical to the evolving water composition. In the southern area, the thermal waters are influenced by inputs of both CO₂ and H₂S, whereas in the northeastern area waters, only CO₂ appears to dominate. Structural controls imposed by the Liquiñe-Ofqui Fault System and the Andean Transverse Faults play a predominant role in directing the ascent of gases, and influencing the geochemical signatures of the thermal waters. This study provides an update about the hydrothermal system related to Villarrica volcano, where new sampling sites were analyzed for the first time and new processes were recognized, constraining the hydrogeochemical model of the geothermal system.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"170 ","pages":"Article 105879"},"PeriodicalIF":1.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forest transpiration in Brazilian drylands: measurement and validation of a hydrological model","authors":"Nazaré Suziane Soares ,&nbsp;José Vidal de Figueiredo ,&nbsp;Carlos Alexandre Gomes Costa ,&nbsp;Italo Sampaio Rodrigues ,&nbsp;José Carlos de Araújo","doi":"10.1016/j.jsames.2025.105896","DOIUrl":"10.1016/j.jsames.2025.105896","url":null,"abstract":"<div><div>Transpiration, particularly in dryland forests, plays a major role in the water cycle. The one-million km² Caatinga Biome is a data-scarce region in the Brazilian Semiarid, where rainy and dry season are clearly distinct. This work aims to measure the natural Caatinga vegetation transpiration using sap flow monitoring (between Feb 2016 and Dec 2017) and to validate the hydrological Distributed Catchment Scale Model (DiCaSM). Measured transpiration <em>in situ</em> was on overall average 0.58 mm.day⁻¹ for rainy and transition seasons. There is evidence that sap flow does not provide a good representation of transpiration in dry seasons: sap flow is high, whereas, according to the Literature, actual evapotranspiration is negligible (&lt;0.01 mm.day⁻¹) due to a very low soil water content, and, thus, transpiration should also be negligible. Transpiration estimated by DiCaSM presented a well-defined seasonal variability, with values close to zero during the driest months, in agreement to previous literature. Overall, the findings contribute to better expertise regarding the transpiration rates in a dryland environment and may be used in water resources management contexts, as the transpiration process gives insight into local water use and availability.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"170 ","pages":"Article 105896"},"PeriodicalIF":1.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geoelectric study in the southwestern end of the Sierra de San Luis: Insights into the broken foreland in the Pampean flat-slab segment","authors":"Augusto F. Morosini ,&nbsp;Noelia B. Vilchez ,&nbsp;Silvana L. Spagnotto ,&nbsp;Andrés D. Richard ,&nbsp;Marina K. Escobares ,&nbsp;Melina A. Quiroga","doi":"10.1016/j.jsames.2025.105892","DOIUrl":"10.1016/j.jsames.2025.105892","url":null,"abstract":"<div><div>The southwestern end of the Sierra de San Luis, located within the Argentinian Pampean flat-slab segment, presents a complex tectonic architecture associated with intraplate deformation in a broken foreland setting. In this study, we use vertical electrical soundings (VES) to investigate the subsurface features in a particular sector of this region, aiming to characterize the geometry and depth of sedimentary basins and the underlying crystalline basement. Twenty-six VES were acquired using a Wenner configuration, reaching up to 316 m in depth. The geoelectrical models reveal three main resistivity domains: a high-resistivity crystalline basement (&gt;500 Ωm), a low-resistivity clastic unit (LRCU; &lt;29 Ωm), and a high-resistivity clastic unit (HRCU; 80–300 Ωm). These resistivity patterns, supported by surface geology and stratigraphic data, allow for the delineation of major tectonic blocks and depocenters. The results highlight a markedly heterogeneous basement topography controlled by N-S reverse and NW-SE oblique extensional faults. Lateral variations in sediment thickness and fault geometries indicate significant control from inherited basement eopalezoic anisotropies, including ductile shear zones and magmatic fabrics. This study provides new geophysical evidence for the segmentation of the foreland in the Sierra de San Luis and underscores the importance of integrating electrical methods in regions affected by thick-skinned tectonics. The findings have implications for neotectonic activity, structural evolution, and groundwater dynamics in intraplate settings.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"170 ","pages":"Article 105892"},"PeriodicalIF":1.5,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}