Latin American Journal of Sedimentology and Basin Analysis
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description: The Latin American Journal of Sedimentology and Basin Analysis (LAJSBA) is the official publication of the Argentinean Association of Sedimentology (AAS). Formerly AAS Revista, it has been published uninterruptedly since 1994. The numbers of the AAS Revista published between 1994 and 2004 are available on the SciELO-Argentina website. The fundamental aim of the LAJSBA is to publish original research papers, reviews and technical notes dealing with all aspects of the sedimentology, sedimentary rocks, sediment dynamics and related disciplines such as basin analysis, stratigraphy, paleoecology, paleogeography, etc. that provide a timely contribution to the advance in this field of the Earth Sciences. LAJSBA is published twice a year, in July and December. Official languages of the journal are Spanish, Portuguese and English. However, taking into account the future expansion of the LAJSBA we will consider favorably those papers submitted in English. Open Access LAJSBA is a "diamond" open access journal, which means that all of its content is available free of charge to the readers and institutions. LAJSBA does not charge authors any Article Processing Charges (APCs). The full texts of the scientific articles published in this journal are available in the Archives section. LAJSBA provides open and immediate access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Indexing Information of LAJSBA LAJSBA is cited in SCOPUS, GeoRef, Latindex, REDIB and SciELO. It has been incorporated to Núcleo Básico de Revistas Científicas Argentinas. LAJSBA is indexed by SCimago Journal Ranking since 2013 and ICI Journals Master List since 2019.
publisher: Asociación Argentina de Sedimentología
language: en
publication name: Latin American Journal of Sedimentology and Basin Analysis
issn: 1669-7316
items: Paleocurrent determination in fine-grained rocks of the Vaca Muerta Formation (Tithonian, Neuquén Basin) through anisotropy of magnetic susceptibility
items: Unveiling a landscape: mapping aeolian dunes in the Argentine Pampa plain using local entropy analysis of DEMs
items: Syn-eruptive sedimentation in the Hualcupén Formation: paleoenvironmental evidence from the Pliocene-Pleistocene period, Caviahue, Neuquén
items: Golfo San Jorge Basin: thematic synthesis, recent developments and a look forward
items: Predictions of the impact of the sea-level rise in Argentina
items: Microfacies textural variability in fluvio-aeolian sandstones from the Avilé Member, Neuquén Basin, Argentina
items: Cenozoic stratigraphy of the Golfo San Jorge Basin (Argentina): an integrated record of tectonic, climatic, and eustatic controls on basin evolution
items: Predictive analysis of total organic carbon (TOC) in shale targets: example from the Lower Cretaceous of the Austral Basin (Patagonia, Argentina) using machine learning on outcrop data
items: Structural framework and evolution of the Golfo San Jorge Basin: a synthesis
items: The Chubut Group (Cretaceous, Golfo San Jorge Basin): A synthesis of its sedimentary petrography
items: Expanding knowledge of hothouse conditions through the study of paleosols in the southern Golfo San Jorge Basin
items: Provenance and depositional processes of extrabasinal (siliciclastic) and intrabasinal (carbonate) particles of the Tithonian–Berriasian Vaca Muerta–Quintuco System (Neuquén Basin, Argentina)
items: Aknowledgement to reviewers 2021-2024
items: A synthesis of palynological data recovered from “Neocomian” deposits of the Golfo San Jorge Basin
items: Stratigraphy of the Chubut Group (Cretaceous, Golfo San Jorge Basin, Argentina): impacts of allogenic controls on the alluvial macro-architecture
items: An overview of the Late Triassic–Pleistocene magmatism in the Golfo San Jorge Basin
items: Insight into cretaceous floras: a synthesis from plant microfossils of the Chubut Group in the Golfo San Jorge Basin
items: Deciphering the origin of linear landforms using different sedimentological tools in the Fiambalá Valley (Catamarca)
items: MiSMoS (MicroScale Morphology System): an inexpensive new method to survey 3D surface micromorphology
items: Early Miocene detrital zircon age from fluvial deposits of La Marcelina Formation in the Deseado Massif, Southern Patagonia, Argentina
items: Late Quaternary palaeochannels in the distal area of the Salado-Juramento fluvial megafan, South America
items: Hydrogeomorphological changes and the erosion-deposition impact in the San Francisco River Basin, northwest Argentina: a multidecadal analysis
items: Landforms, sediments, and soils: Quaternary study cases of Argentina
items: Diagenetic evolution of the Permian Tunas Formation, Claromecó Basin, Buenos Aires province, Argentina: its impact on porosity and reservoir characteristics
items: Sand pipes as potential indicators of seismicity in the Casa Grande Formation, northwestern Argentina
items: Fire effects on rock weathering in the North Patagonian Andean Range
items: Editorial
items: Soil-geomorphic relationships in a northeastern Patagonian tidal salt marsh, Península Valdés, Argentina
items: Origin and evolution of coastal lagoons from the pampean region: Mar Chiquita, Las Brusquitas, Reta (Buenos Aires province, Argentina)
items: Recent disturbance events recorded in the sedimentary infill of Lago Guillelmo (Argentina): tephra falls and hydrogeomorphic processes

Paleocurrent determination in fine-grained rocks of the Vaca Muerta Formation (Tithonian, Neuquén Basin) through anisotropy of magnetic susceptibility
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description: This study integrates sedimentological, petrographic, and magnetic fabric analyses of the Tithonian deposits of the Vaca Muerta Formation exposed in the southern sector of the sierra de la Vaca Muerta. The sedimentological analysis allowed the identification of four facies associations (FA) and two depositional environments. FA1 comprises distal outer carbonate ramp deposits, FA2 represents mixed outer ramp deposits, and FA3 belongs to turbiditic events. These FA correspond to the lower member of the unit and constitute a mixed carbonate–siliciclastic outer ramp system. FA4 comprises the whole Los Catutos Member, and it is interpreted as outer carbonate–ramp deposits. Magnetic mineralogy studies, together with mean magnetic susceptibility values and the dominant mineralogical composition indicate a paramagnetic influence (clays, muscovite, biotite) as the primary control on the AMS properties. IRM studies indicate a minor contribution of ferromagnetic particles, such as titanomagnetite and hematite. The AMS study enabled the recognition of sedimentary fabrics, as well as inverse fabrics and petrofabrics related to post-depositional processes. Sedimentary fabrics include horizontal fabrics related to hemipelagic settling mechanisms and flow-aligned fabrics associated with flat-bed and current-ripple migration processes. Inverse fabrics are attributed to the presence of ferroan calcite while post-depositional fabrics include mechanisms such as bioturbation and dolomitization. Flow-aligned fabrics allowed the determination of two paleocurrent data sets: one trending towards NW, composed of sandy turbiditic intervals, and another perpendicular to it, trending SW–NE to E–W. The first case represents sedimentary processes that evolved across-slope while the second case implies the action of along-slope currents. Sedimentary features of these deposits, such as current-ripple lamination, erosional cut-and-fill surfaces, intraclastic fabrics, and bioturbated horizons, might …
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creator: Ignacio Tamagno
creator: Diego Alejandro Kietzmann
creator: Luis María Fernández de la Rúa
creator: María Paula Iglesia Llanos
rights: Copyright (c) 2026 Ignacio Tamagno, Diego Alejandro Kietzmann, Luis María Fernández de la Rúa, María Paula Iglesia Llanos https://creativecommons.org/licenses/by-nc/4.0
date: 2026-03-18
publication date: 2026-03-18

Unveiling a landscape: mapping aeolian dunes in the Argentine Pampa plain using local entropy analysis of DEMs
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description: The Pampa plain of Argentina, southern South America, constitutes a vast low-relief landscape whose Neogene-Quaternary history was dominated by aeolian deposition and morphogenesis. Although dunes exist in the region—mostly inactive under current climatic conditions—their full spatial extent and morphology have remained partially obscured by vegetation (grassland) and agricultural activity, rendering them difficult to detect with conventional digital elevation model (DEM) visualization techniques. To address this challenge, we developed DemEntropy, a novel method that applies a local entropy filter to a DEM to quantify topographic disorder and highlight organized geomorphic patterns. This open-source software package is freely distributed and provides a reproducible method for enhancing subtle topographic features based on their textural properties. Application of DemEntropy to TanDEM-X data for the Pampa plain yielded two significant results. First, it successfully enhanced the boundaries and aeolian morphologies of the known Central Pampean Dunefield unit (CPD), of the Pampean Sand Sea, demonstrating the robustness of the method. Second, and more notably, it revealed extensive, previously undocumented aeolian features northeast of the Tandilia range, in the loess domain (Loess and loess-like mantles and blowouts unit, LMB), where such features are not discernible in standard hillshade models. These findings demonstrate the efficacy of local entropy analysis for geomorphological mapping and reveal a more complex and extensive history of aeolian activity in the region than previously recognized. By providing this tool as a freely available software package, we aim to enable the wider community to apply this powerful technique to the study of subtle aeolian and fluvial landscapes in other vegetated and low-relief settings globally.
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creator: Rafael Grimson
creator: Alfonsina Tripaldi
creator: Daniela Negro Sirch
rights: Copyright (c) 2026 Rafael Grimson, Alfonsina Alfonsina, Daniela Negro Sirch https://creativecommons.org/licenses/by-nc/4.0
date: 2026-06-03
publication date: 2026-06-03

Syn-eruptive sedimentation in the Hualcupén Formation: paleoenvironmental evidence from the Pliocene-Pleistocene period, Caviahue, Neuquén
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description: The Hualcupén Formation constitutes the basal unit of the Pliocene-Recent Caviahue-Copahue Volcanic Complex (CCVC), located in the Southern Volcanic Zone (Fig. 1) to the north of the Patagonian Andes (37°50´S – 71°00´W). In plan-view, the complex is a rectangular depression up to 14 km wide and 18 km long, known as the Bajo del Agrio (Groeber, 1925) or Agrio/Caviahue Caldera (Pesce, 1989). The Pliocene-Pleistocene Hualcupén Formation (Muñoz Bravo et al., 1989; Linares et al., 1999; Sruoga and Consoli, 2011a) comprises a succession of effusive and explosive volcanic rocks interbedded with sedimentary units (Pesce, 1989; Varekamp et al., 2006), exposed along the caldera walls. Although the unit has been mentioned in regional studies, a detailed analysis of its deposits to comprehensively understand the relationship between volcanic and sedimentary processes in a paleoenvironmental context has been lacking. Through a detailed facies and depositional process analysis of the lower Hualcupén Formation, the main goals were to: (i) analyze the stratigraphy and sedimentology of the lower section of the succession, (ii) elucidate the interplay between volcanic and sedimentary processes, and (iii) interpret the paleoenvironmental conditions during deposition. The unit was initially defined by González and Vergara (1962) in Chile as the Cola de Zorro Formation, with Pesce (1989) assigning the name Hualcupén Formation for the equivalent Argentine unit, referring to the volcanic complex's basal unit. Lithologically, it has thicknesses between 400 and 800 m constituted by successions of potassium-rich andesites and basaltic andesites with intercalations of volcanic agglomerates (Pesce, 1989). Furthermore, Mazzoni and Licitra (2000) estimated a predominance of debris flow conglomeratic deposits in the middle-lower parts of the unit, while Mazzoni (1998) recognized a dominance of pyroclastic flow deposits in the middle to upper sections of the unit. Five informal stratigraphic secti…
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creator: Gabriela Almada
creator: Joaquín Bucher
creator: Irene Hernando
rights: Copyright (c) 2026 Gabriela Almada, Joaquín Bucher, Irene Hernando https://creativecommons.org/licenses/by-nc/4.0
date: 2026-03-03
publication date: 2026-03-03

Golfo San Jorge Basin: thematic synthesis, recent developments and a look forward
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description: This contribution provides an overview of the content of this Special Number of the Latin American Journal of Sedimentology and Basin Analysis, which explores the geological evolution of the Golfo San Jorge Basin and the challenges it faces within the current context of hydrocarbon resource depletion and global warming. The Special Number comprises eight peer-reviewed articles synthesizing current knowledge across multiple disciplines. The topics covered include: (i) magmatic evolution (Navarrete); (ii) structural geology (Allard et al.); (iii) stratigraphy and provenance (Paredes et al.; Olazábal et al.; Foix et al.); (iv) paleosol development (Lizzoli and Raigemborn); and (v) Cretaceous biostratigraphy (Pérez Loinaze; De Sosa Tomas and Vallati). These contributions present recent advances in their respective fields and highlight critical unresolved questions that must be addressed to further our understanding of the geological evolution of the Golfo San Jorge Basin.
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creator: José M. Paredes
rights: Copyright (c) 2025 José M. Paredes https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 1
ending page: 5

Predictions of the impact of the sea-level rise in Argentina
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description: Sea level is rising and it is expected to continue rising as the atmosphere is warming inducing glacier melting. Based on this melting a minimum of 0.4 m of sea level rise (SLR) is expected for the year 2100. Coastal erosion is the more evident consequence of this SLR. At estuarine areas these effects are more difficult to discern. In some areas climate is warming and rains are increasing, and are thought to continue doing so in Buenos Aires; but they are decreasing in Patagonia. Therefore, estuarine areas, freshwater and salt marshes have different responses along the Argentine coast. More important are the effects in urban areas where planners and administrators have systematically disregarded the subject. In low-lying areas as Samborombón Bay the SLR will cause a surface retreat of the salt-fresh water interactions. Therefore, General Lavalle city will be more dependant of the surface freshwater runoff of the Channel 2. Flash floods today can affect the city of San Clemente del Tuyú but the performance of the discharge pipelines depends on the meteorological effects on the tides. Flash floods have also affected coastal cities of the desertic Patagonia: Puerto Madryn and Comodoro Rivadavia have suffered unprecedented floods during recent years. Two models applied to coast evolution in response to SLR. Bruun`s model predicts shore erosion and deposition below the depth where there is no wave action (closure depth). However, in low-lying areas where there is enough sediment availability the onshore migration of bedforms (beaches, cheniers) can occur. Changes in estuarine areas are more difficult to predict. Tidal prisms can increase significantly in microtidal coasts due to SLR, but in macrotidal coasts these increments were not significant. Another effect of the SLR occurs at the hydrogeological interphase between fresh and salt waters. The simulation of these interactions should be carefully estimated considering the groundwater discharge and the climate change ef…
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creator: Federico Ignacio Isla
rights: Copyright (c) 2025 Federico Ignacio Isla https://creativecommons.org/licenses/by-nc/4.0
date: 2025-12-26
publication date: 2025-12-26
starting page: 137
ending page: 149

Microfacies textural variability in fluvio-aeolian sandstones from the Avilé Member, Neuquén Basin, Argentina
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description: Understanding the internal microtextural heterogeneity of fluvio-aeolian successions can provide valuable insights both on the depositional mechanisms associated with their origin and on their quality as reservoir rocks. Microfacies analysis enables the integration of thin-section textural studies with outcrop-scale observations, which substantially improves our understanding of depositional dynamics across different subenvironments, as well as the interpretation of petrophysical properties distribution. This approach is particularly relevant for reservoirs such as the Avilé Member of the Agrio Formation, as small-scale textural variability has become increasingly important due to the implementation of enhanced recovery techniques in recent years. This unit is characterised by fluvial and aeolian sandstones and constitutes one of the main conventional hydrocarbon reservoirs in the Neuquén Basin. In light of this, the general objective of this work was to compare aeolian and fluvial laminae to improve small-scale textural heterogeneities modelling of the defined facies from mesoscopic analysis. The methodology involved first describing and interpreting the units at the mesoscopic scale, and then characterising the different lamina types at the microscopic scale to define the microfacies. Five distinct lamina types, each representing a specific sedimentary process, were identified in the field within a well-established stratigraphic framework. Their textural petrographic characterisation allowed the definition of five corresponding microfacies —three associated with aeolian deposits and two with fluvial deposits. The results suggest a strong correspondence between textural parameters and the sedimentary process responsible for deposition. The analysis showed both differences among deposits formed by the same transport and depositional agent, and similarities between aeolian and fluvial deposits formed by analogous depositional mechanisms. This suggests that the deposi…
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creator: Eusebio Coelho Tenazinha
creator: Joaquín Perez Mayoral
creator: Gonzalo Diego Veiga
rights: Copyright (c) 2025 Eusebio Coelho Tenazinha, Joaquín Perez Mayoral, Gonzalo Diego Veiga https://creativecommons.org/licenses/by-nc/4.0
date: 2025-12-26
publication date: 2025-12-26
starting page: 168
ending page: 191

Cenozoic stratigraphy of the Golfo San Jorge Basin (Argentina): an integrated record of tectonic, climatic, and eustatic controls on basin evolution
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description: The Golfo San Jorge Basin (GSJB) preserves the thickest Cenozoic stratigraphic record in extra-Andean Patagonia (Argentina), reaching approximately 1500 meters. This record was subdivided into three major second-order transgressive regressive (TST-RST) sedimentary sequences: (1) The early Paleogene T-R cycle (~ 600 m thick; early Paleocene–late Eocene), comprising the Salamanca Formation (marine), Río Chico Group (fluvial), and part of Sarmiento Formation (pyroclastic loess). This sequence reflects a marine-to-continental transition, with an early marine stage marked by tidally-influenced, shallow-marine and inner-shelf sedimentation, followed by fluvial systems and long-lived accumulation and reworking of fine ash in a low-gradient continental setting. (2) The late Paleogene-early Neogene T-R cycle (~ 200 m thick, late Eocene-early Miocene), composed of the El Huemul Formation (marine) and the upper part of Sarmiento Formation (pyroclastic deposits). (3) The Neogene T-R cycle (~ 700 m thick; early–middle Miocene), includes the Chenque Formation (marine) and the Santa Cruz or Escalante Formation (fluvial-eolian). The three marine second order TSTs share similar temporal duration (<5 million years) and sedimentation patterns are strongly influenced by continental slope inheritance. However, the continental second-order RSTs differ significantly: (i) the early Paleogene RST lasted ~ 22 million years, compared with the ~ 10 million years of the late Paleogene-early Neogene cycle and the ~ 5 million years of the Neogene; (ii) the Paleogene records extensive global climatic fluctuations, whereas the Neogene is characterized by a single wet to dry cycle; (iii) pyroclastic deposits dominate the early Paleogene and late Paleogene-early Neogene sequences, but they are nearly absent in the Neogene; (iv) the first two second order continental cycles preserves an exceptional assemblage of continental mammal faunas, serving as a biostratigraphic reference for South America. Alth…
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creator: Nicolás Foix
creator: José Matildo Paredes
creator: Francisco Emanuel Oporto Romero
creator: José Oscar Allard
rights: Copyright (c) 2025 Nicolás Foix, José M. Paredes, Francisco Emanuel Oporto Romero, José Oscar Allard https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 68
ending page: 80

Predictive analysis of total organic carbon (TOC) in shale targets: example from the Lower Cretaceous of the Austral Basin (Patagonia, Argentina) using machine learning on outcrop data
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description: The Río Mayer Formation (Lower Cretaceous) of the Austral Basin, Patagonia, is a key source rock for unconventional reservoirs. This study explores the potential of machine learning (ML) for predicting Total Organic Carbon (TOC) content using outcrop data, a novel approach compared to traditional subsurface data applications. Employing dimensional reduction techniques (PCA, T-SNE, UMAP), the analysis revealed clear clustering of high TOC values in feature space, supporting the feasibility of predictive modeling. Three ML models —Logistic Regression, Support Vector Classifier (SVC), and KNearest Neighbors (KNN)— were tested using a feature set derived from ANOVA F-Score rankings. Dimensionality reduction improved model performance, with SVC achieving the most robust results. Despite limited labeled samples, predictions across models were consistent, identifying a promising region for high TOC. The study highlights the importance of integrating geological variables and XRD data in TOC modeling and emphasizes the need for expanded datasets and additional sedimentary sections to enhance regional interpretations.
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creator: Sebastian M. Richiano
creator: Federico Ares
rights: Copyright (c) 2025 Sebastián M. Richiano, Federico Ares https://creativecommons.org/licenses/by-nc/4.0
date: 2025-12-26
publication date: 2025-12-26
starting page: 121
ending page: 136

Structural framework and evolution of the Golfo San Jorge Basin: a synthesis
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description: The Golfo San Jorge Basin evolved through a complex multiphase structural history from the Middle Jurassic to the Neogene. Its stratigraphic record captures key tectonic events in central extra-Andean Patagonia during Gondwana fragmentation and the Andes construction, allowing us to refine and calibrate multiscale structural processes associated with extension and positive tectonic inversion. The structural architecture reflects the interplay of upper-crustal remote stress, active basement structures, coaxial and non-coaxial extensional reactivations, short-wavelength tectonic inversion, thermal subsidence, and mantle processes. A comprehensive understanding of these interactions is crucial for improving regional basin models with broader implications for tectonic and petroleum system studies.
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creator: José Oscar Allard
creator: Nicolás Foix
creator: José M. Paredes
creator: Raúl E. Giacosa
creator: Sebastián A. Bueti
creator: Francisco E. Oporto Romero
creator: Agustín R. Rodríguez
rights: Copyright (c) 2025 José O. Allard, Nicolás Foix, José M. Paredes, Raúl E. Giacosa, Sebastián A. Bueti, Francisco E. Oporto Romero, Agustín R. Rodríguez https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 19
ending page: 31

The Chubut Group (Cretaceous, Golfo San Jorge Basin): A synthesis of its sedimentary petrography
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description: This study presents a synthesis of petrographic analyses of the cretaceous Pozo D-129, Matasiete, Castillo, and Bajo Barreal formations in the Golfo San Jorge Basin, highlighting the influence of volcanic activity and sediment supply on the evolution of the Chubut Group. Data from outcrops in the San Bernardo Fold Belt and from the subsurface indicate that sandstone compositional variability was controlled by shifts in sediment source areas, linked to regional tectonic processes and active volcanism. Sandstones exhibit feldspatho-lithic and litho-feldspathic qFL, fQL, IQF to qLF composition detrital modes, with spatial and temporal variations in volcanic, pyroclastic lithic, feldspar and quartz components. The sediment sources for the outcrops in the San Bernardo Fold Belt include the Paleozoic igneous-metamorphic basement, Middle-Upper Jurassic volcanic and volcaniclastic rocks (Lonco Trapial Group), and acidic and pyroclastic sequences assigned to the Marifil Group. In contrast, the South Flank records a broader range of petrofacies, reflecting a combination of distal and local sources. In addition to the provenance of the Andes Cordillera, this sector received sediment contributions from Jurassic rocks exposed in the Deseado Region and older crystalline basement units. Andean volcanism dominates across all units, contributing direct volcanic ash fallout and reworked pyroclastic material.
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creator: Sabrina Olazábal
creator: Maisa Andrea Tunik
creator: José Matildo Paredes
creator: José Oscar Allard
creator: Nicolás Foix
rights: Copyright (c) 2025 Sabrina Olazábal, Maisa A. Tunik , José M. Paredes, José O. Allard , Nicolás Foix https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 44
ending page: 56

Expanding knowledge of hothouse conditions through the study of paleosols in the southern Golfo San Jorge Basin
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description: Hothouse periods, such as the mid-Cretaceous and early Eocene, were times of global warming with high levels of greenhouse gases, elevated temperatures, and ice-free poles that provide a case study for understanding past climate dynamics. This study examines the paleo-Ultisols from the Bajo Barreal Formation (BBF; Cenomanian) and the Las Flores Formation (LFF; early Eocene) in central Patagonia (southern region of the Golfo San Jorge Basin). Due to their prolonged soil formation, these well-developed paleosols serve as valuable climate indicators. These paleosols were analyzed using a multi-proxy approach to understand their significance during those two periods in the Southern Hemisphere. The BBF Ultisols (mid-Cretaceous, ~51° paleo-S) display kaolinite-rich Bt horizons, formed under intense chemical weathering conditions and leaching processes, linked to a temperate and humid climate. On the other side, the LFF Ultisols (early Eocene, ~52° paleo-S) with kaolinite-dominated Bt and/or Btv horizons reflect their formation under higher chemical weathering and leaching processes, under a temperate-tropical and humid climate. For the times of formation of both BBF and LFF paleo-Ultisols, both localities were within the Warm Temperate climate zone. In contrast, this zone currently extends to approximately 40° N and S latitude. Present-day Patagonia is in the Arid climate zone, with much drier and cooler climate that contrasts with the warmer, wetter conditions of the Cenomanian and early Eocene localities analyzed. These findings highlight significant latitudinal displacement of climate zones during hothouse periods, emphasizing their importance in understanding past climate dynamics and providing insights into future climate change scenarios.
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creator: Sabrina Lizzoli
creator: María Sol Raigemborn
rights: Copyright (c) 2025 Sabrina Lizzoli, María Sol Raigemborn https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 57
ending page: 67

Provenance and depositional processes of extrabasinal (siliciclastic) and intrabasinal (carbonate) particles of the Tithonian–Berriasian Vaca Muerta–Quintuco System (Neuquén Basin, Argentina)
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description: During the Early Jurassic–Early Cretaceous, between 32° and 40° S latitude, a steeply dipping active subduction zone along the western margin of Gondwana led to the development of a magmatic arc and a large back-arc depression known as the Neuquén Basin. A thick record of Tithonian–Berriasian organic rich sediments resulted from back-arc subsidence, expansion of the marine realm and flooding of the basin, which was presumably connected to the proto-Pacific Ocean through gaps in the magmatic arc. Widespread and persistent starved conditions in the basinal areas of the Neuquén Sea allowed the accumulation of a thick record of hybrid siliciclastic-carbonate sediments (“Vaca Muerta facies”), while along the eastern and southeastern cratonic basin margins, inner ramp deposits (“Quintuco facies”) were dominated by biogenic and clastic carbonates with subordinated muds, sands and salt deposits. The “Vaca Muerta Facies” is essentially composed of two (aggradational and progradational) accommodation sets. The aggradational set consists of hundred meters thick and widely distributed organic-rich silty and clayey mudstones with varying proportion of hemipelagic/pelagic siliceous and carbonate contribution, accumulated in the more distal sectors of the marine ramp under anoxic to suboxic conditions. The progradational sets, developed between the inner ramp and the deeper sectors of the basin, extend hundreds of kilometres both along and across the depositional dip, showing sigmoidal or clinoform geometries with well-defined topset, foreset, and bottomset configurations. In comparison with the aggradational sets, these intraplatform clinoforms are enriched in intrabasinal carbonate components and exhibit a reduction in organic matter content denoting a comparative increase in oxygenation of the marine bottom waters. If the productivity of pelagic biogenic carbonates was approximately constant at the basin level, the increase in the proportion of these components in the intraplat…
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creator: Luis Spalletti
creator: Ernesto Schwarz
creator: Gonzalo D. Veiga
rights: Copyright (c) 2025 Luis Spalletti, Ernesto Schwarz, Gonzalo D. Veiga https://creativecommons.org/licenses/by-nc/4.0
date: 2025-12-26
publication date: 2025-12-26
starting page: 150
ending page: 167

Aknowledgement to reviewers 2021-2024
type: item
subject: Editorial
  topic: section
creator: José I. Cuitiño
rights: Copyright (c) 2024 José I. Cuitiño https://creativecommons.org/licenses/by-nc/4.0
date: 2024-12-23
publication date: 2024-12-23

A synthesis of palynological data recovered from “Neocomian” deposits of the Golfo San Jorge Basin
type: item
description: This contribution provides a synthesis of the palynological studies carried out on “Neocomian” units of the Golfo San Jorge Basin. Additionally, a revision of the palynological zones established for these units in previous works is presented, incorporating insights from new contributions and recent taxonomic novelties. Based on the palynological record, the age of the Las Heras Group is considered as not younger than Hauterivian at the northern and southern flanks of the Golfo San Jorge Basin. In contrast, the age of this group extends to the Aptian in the western area. Nevertheless, more detailed palynological studies and an evaluation of the current status of the stratigraphic units recognized in the analyzed wells are needed to confirm and expand these results.
subject: Special Issue
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creator: Valeria Perez Loinaze
rights: Copyright (c) 2025 Valeria Perez Loinaze https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 81
ending page: 90

Stratigraphy of the Chubut Group (Cretaceous, Golfo San Jorge Basin, Argentina): impacts of allogenic controls on the alluvial macro-architecture
type: item
description: The Chubut Group (Cretaceous, Golfo San Jorge Basin) is a continental succession up to 6,000 meters thick, preserved in an endorheic basin. Its basal depositional system includes the fluvial Matasiete Formation and the lacustrine Pozo D-129 Formation, the main source rock for the hydrocarbons of the basin. The Matasiete Formation (Aptian) represents a high-accommodation, exotic fluvial system with headwaters in the present-day Cañadón Asfalto Basin (CAB), referred to as the Los Adobes Formation. Sediment was transported southward to a saline-alkaline lake (Pozo D-129 Formation) through N-S sedimentary corridors in an extensional setting. The overlying depositional system is integrated by the Castillo and Mina del Carmen formations (Albian-Cenomanian?), and it consists of reworked volcaniclastic particles in drainage catchments within a W-E elongated extensional basin, disconnected from the CAB. The subsequent depositional system includes the Bajo Barreal Formation (Cenomanian- Coniacian?), containing the main hydrocarbon reservoirs. It shows varied stacking density in hundreds of meters thick cycles, linked to climatic cycles. Low net-to-gross fluvial stratigraphy featuring small-scale channel belts and paleosols indicates a temperate, subhumid/humid climate with seasonal rainfall. High net-to-gross fluvial stratigraphy records larger-scale channel belts interbedded with paleosols developed in a warmer, humid climate with perennial rainfall. The uppermost depositional system includes the paleosol-rich Laguna Palacios Formation at basin margins, with maximum thicknesses along syncline axes, and the red-colored, anastomosing fluvial systems of the Maastrichtian Colhué Huapi Formation that fill incised valleys. Both units are equivalent to the upper strata of Meseta Espinosa and El Trébol formations in the subsurface, showing degradational features marking the onset of surface uplift in the San Bernardo Fold Belt.
subject: Special Issue
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creator: José M. Paredes
creator: Nicolás Foix
creator: José O. Allard
creator: Sabrina Lizzoli
creator: Sabrina X. Olazábal
creator: Maisa A. Tunik
rights: Copyright (c) 2025 José Matildo Paredes, Nicolás Foix, José O. Allard, Sabrina Lizzoli, Sabrina X. Olazábal, Maisa A. Tunik https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 32
ending page: 43

An overview of the Late Triassic–Pleistocene magmatism in the Golfo San Jorge Basin
type: item
description: The Patagonian Late Triassic–Pleistocene magmatic history encompasses multiple intraplate and subduction–related events associated with diverse geodynamic settings. Key episodes include the Late Triassic and Late Cretaceous–Paleocene flat slabs, the Cenozoic subduction of two mid-ocean ridges, slab break-off and tearing events during the Jurassic, Cretaceous–Paleocene, and Late Miocene–Pleistocene, as well as the influence of the mantle transition zone from the latest Eocene to the Middle Miocene. These processes collectively triggered significant magmatic episodes across the region. This overview highlights the main features of these magmatic events, their associated geodynamic contexts, and the proposed petrogenetic models, focusing on the central Patagonian region, including the Golfo San Jorge Basin and its surrounding areas.
subject: Special Issue
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creator: César R. Navarrete
rights: Copyright (c) 2025 César Rodrigo Navarrete Granzotto https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 6
ending page: 18

Insight into cretaceous floras: a synthesis from plant microfossils of the Chubut Group in the Golfo San Jorge Basin
type: item
description: This study provides a comprehensive review of key advances in micropaleontological research of the Chubut Group in the Golfo San Jorge Basin during the twenty-first century, with a particular emphasis on the plant microfossil record of two critical stratigraphic units: the Pozo D-129 Formation and the Lago Colhué Huapi Formation. The Pozo D-129 Formation, which outcrops at the Sierra Silva anticline, contains gyrogonites and utricles belonging to the Characeae and Clavatoraceae families, as well as a palynoflora assemblage that includes primitive angiosperm pollen grains. The analyzed microfossil assemblages suggest a late early Aptian age for these deposits and provide valuable insights into the freshwater paleoenvironment, which developed under semiarid conditions. In contrast, the microfossil record from the upper levels of the Lago Colhué Huapi Formation, recovered from outcrops at the headwaters of the Río Chico, did not yield charophytes but revealed rich palynological assemblages, including several megaspores from the orders Salviniales, Isoetales, and Selaginellales, along with additional palaeobotanical remains such as charcoal. These findings significantly contribute to interpreting a late Maastrichtian age and facilitate the reconstruction of the vegetation that thrived in freshwater environments under warm and humid climatic conditions.
subject: Special Issue
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creator: Andrea De Sosa Tomas
creator: Patricia Vallati
rights: Copyright (c) 2025 Andrea De Sosa Tomas, Patricia Vallati https://creativecommons.org/licenses/by-nc/4.0
date: 2025-07-02
publication date: 2025-07-02
starting page: 91
ending page: 102

Deciphering the origin of linear landforms using different sedimentological tools in the Fiambalá Valley (Catamarca)
type: item
description: The current study is centered on the morphological, textural, and compositional characterization of several linear landforms identified in the west and center of the Fiambalá Valley, in the western region of the Catamarca province (Argentina), along the terraces of the Apocango River. These landforms are slightly asymmetric to symmetric, with rounded crests, a few meters high (between 0.3 and 3.5 m) and several meters wide (from 8 to 14.5 m). They have straight to slightly sinuous ridges with NE-E to SW-W direction and are arranged as isolated bodies. The superficial cover has a bimodal frequency distribution with a primary mode in medium to coarse pebble (-4.5 to -3.5 ?) and a secondary mode in fine sand (2.5 ?). Gravel clasts are sub-rounded, with moderate sphericity, and predominantly compact-elongated shape. The analysis of high-resolution photographs of the superficial cover showed they present an open to moderate packing (44.49 - 58.60% of clasts). In a cross-sectional profile, it was observed that internally they consist of fine to medium sand (x: 2.66 - 1.31 ?). Gravel composition is made primarily by clasts of green sedimentary lithics (22.92 - 32.72%), followed by acidic volcanic lithics (15 - 21.49%), purple sedimentary lithics (13.72 - 17.04%), and basic (10.60 - 17.78%) and intermediate (9.74 - 12.93%) volcanic lithics, thus classified as lithic gravels. The sandy fraction is composed of lithics (35.71 - 47.51%), followed by quartz (23.59 - 37.92%), and feldspars (19.80 - 32.76%); consequently, classified as feldspathic litharenites. Regarding the lithic fragments, volcanic types predominate (27.41 - 37.70%), being those of acidic composition with felsitic and microgranular paste (20.06 - 31.15%) the most represented. The thicker superficial cover with open to moderate packing is interpreted as poorly evolved desert pavement. Deposit composition suggests that the main contribution of the gravelly and sandy material comes from the west (Sistema de Famati…
subject: Research Papers
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creator: Delfina Fernandez Molina
creator: Patricia L. Ciccioli
creator: Leopoldo D. Serpa
creator: Paloma Amado Silvero
rights: Copyright (c) 2024 Delfina Fernandez Molina, Patricia L. Ciccioli, Leopoldo D. Serpa, Paloma Amado Silvero https://creativecommons.org/licenses/by-nc/4.0
date: 2024-12-04
publication date: 2024-12-04

MiSMoS (MicroScale Morphology System): an inexpensive new method to survey 3D surface micromorphology
type: item
description: Microscale morphology in coastal environments is complex to study due to both the large spatial and temporal variability. No direct instrumentation is available to map the micromorphology in detail. The aim of this article is to describe the application of the newly developed MiSMoS (MicroScale Morphology System) methodology for mapping surface and small-scale morphologic features such as ripples, rills, and small courses, as well as to demonstrate its advantages and limitations. A set of measurements on a perched beach that offers varied microforms was carried out as a case study example. The MiSMoS consists of a table of 1.6 m x 1.6 m square aluminum structure with six L-shaped rails on top to mobilize a sensor-carrying structure, which is supported on 4 legs (0.60 m high). The sensor-carrying structure is built with two cameras and a Laser Distance Meter (LDM), with cameras at a fixed angle of 20°. In the operating procedure for high-resolution mapping, the sensor-carrying structure is manually moved sequentially capturing images that cover a surface of 0.60 x 0.60 m, with 75% overlap. High-resolution 3D models were generated from the images using Structure-from-Motion, Multi-View-Stereo (SfM-MVS) technique. MiSMoS has numerous advantages over commercial instrumentation: 1) it can map topography at a high resolution, 2) it is easy to build and deploy, 3) it is inexpensive, and 4) in one operation, a high-resolution map of an area of 2.25 m2 can be obtained in about 15-20 min, whereas other systems usually only provide profiles.
subject: Research Papers
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creator: Yajaira Cristina Alquinga Salazar
creator: Sibila A. Genchi
creator: Lucas Nuciari
creator: Vanesa L. Perillo
creator: M. Cintia Piccolo
creator: Gerardo M. E. Perillo
rights: Copyright (c) 2025 Yajaira Cristina Alquinga Salazar, Sibila A. Genchi, Lucas Nuciari, Vanesa L. Perillo, M. Cintia Piccolo, Gerardo M. E. Perillo https://creativecommons.org/licenses/by-nc/4.0
date: 2025-12-26
publication date: 2025-12-26
starting page: 103
ending page: 120

Early Miocene detrital zircon age from fluvial deposits of La Marcelina Formation in the Deseado Massif, Southern Patagonia, Argentina
type: item
description: The La Marcelina Formation (LMF) in the southern Deseado Massif area (c. 47° 55' S) represents a 23 m thick sedimentary succession deposited within a low-energy fluvial paleoenvironment. The age of this unit, formerly considered as Eocene due to its palynological assemblage, is adjusted by zircon U-Pb Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) from a sandstone bed at the middle part of the unit. The results reveal a maximum depositional age of ~20 Ma (Early Miocene, Burdigalian). The detrital zircon provenance analysis indicates zircon grains originated mostly in the Jurassic, with limited contributions from the Cretaceous, Permian, and Paleocene. The new age for LMF allows correlating these beds to the upper section of the continental Río Leona Formation in the southern Austral-Magallanes Basin.
subject: Short Notes
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creator: Inés Aramendía
creator: Sol Noetinger
creator: Roberto Pujana
creator: David Barbeu
creator: Juan García-Massini
creator: Sebastián Mirabelli
rights: Copyright (c) 2024 Inés Aramendía, Sol Noetinger, Roberto Pujana, David Barbeu, Juan García-Massini, Sebastián Mirabelli https://creativecommons.org/licenses/by-nc/4.0
date: 2024-08-27
publication date: 2024-08-27

Late Quaternary palaeochannels in the distal area of the Salado-Juramento fluvial megafan, South America
type: item
description: The Gran Chaco fluvial systems, South America, constitute a significant type of fluvial record for the modern Andean foreland basin. The Salado-Juramento fluvial megafan (SJFM), one of the largest systems of South America, shows distinctive morphologic and sedimentologic characteristics. The SJFM, developed after the southward Salado-Juramento river displacement, shows numerous paleochannels with an eastward distributive pattern from its apex in the Sierras Subandinas. In this work, we analyze the palaeohydrological attributes and the sedimentology of two paleochannel sections located in distal areas of the SJFM, with the aim to collect stratigraphic and sedimentologic data to infer the dynamics of infill of those paleochannels. From each succession, sediment samples for sedimentologic (mineralogy and grain size) and chronologic analyses were taken. The paleochannels with-to-thickness ratio (W/T) show values between 9.4 and 16.1 (mean 12.75) for the distal area of the SJFM, corresponding to ribbon channels. The paleochannel infill is composed of very fine to fine sand, with a sand and clay composition related to the Salado River. These deposits are covered by layers of eolian clayed silt deposits. The geomorphology, paleohydrologic attributes, sedimentology, and numerical datings suggest a distributive paleodrainage with channels active during the MIS 3 (62-28 Ka BP). A fluvial aggradational phase is interpreted for the MIS 3, mainly represented by sinuous channels infill suggesting numerous divergent rivers in the distal SJFM. By the MIS 2, the activity of the fluvial system diminishes being replaced by clayed silt eolian sedimentation.
subject: Research Papers
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creator: María Belén Thalmeier
creator: Leticia Rodríguez
rights: Copyright (c) 2024 María Belén Thalmeier , Leticia Rodríguez https://creativecommons.org/licenses/by-nc/4.0
date: 2024-12-23
publication date: 2024-12-23

Hydrogeomorphological changes and the erosion-deposition impact in the San Francisco River Basin, northwest Argentina: a multidecadal analysis
type: item
description: Modifications of wetland and forest areas are studied, in particular, to establish to what extent they are sensitive to natural changes (e.g., increased precipitation and/or temperature) in addition to human activities (e.g., advancing agricultural frontier, deforestation, channelizations). The San Francisco River Basin (SFRB; 1,789 km2) is located in the Northwest of Argentina in the Geological Province of Nortwestern Pampean Ranges (Sierras Pampeanas Noroccidentales), between 27°40'S and 28°25'S, and 65°15'W and 65°45'W). In recent decades, agricultural development and management in the middle and lower SFRB generated rural channelizations (the largest of 10 km at the basin outlet between 2005-2015), drainage of wetland forests, deforestation of native dry forest since 1995 and changes in land use. In addition, a 200 mm increase in mean annual rainfall since 1972 and an increase in extreme hydrological events, are registered. These modifications produced changes in local base level, erosive processes of retreat and the development of new river channels from upstream, increasing flow velocities, flow rates, and sediment discharge. The intensified erosive processes resulted in four new river courses in the middle and lower basin, incorporating the SFRB into the Marapa river basin, changing from arheic to endorheic behaviour, and generating the contribution of liquid and solid flows to the system of which it is now a part. The aim of this study is to examine the development of the new hydrographic network within the SFRB between 1990 and 2018 and to calculate the solid and liquid discharges generated by the new network. The hydrographic network formed by the rivers El Abra, Ovanta, San Francisco and Suncho creek, was digitized in the open-source software QGIS 3.18.3 on the basis of the visual interpretation of satellite imagery. The lengths of the rivers were automatically calculated and exported to a spreadsheet to determine the downstream expansion of the river net…
subject: Research Papers
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creator: María Antonella Isuani
creator: Sergio Miguel Georgieff
creator: María Soledad Bustos
rights: Copyright (c) 2024 María Antonella Isuani, Sergio Miguel Georgieff, María Soledad Bustos https://creativecommons.org/licenses/by-nc/4.0
date: 2024-12-23
publication date: 2024-12-23

Landforms, sediments, and soils: Quaternary study cases of Argentina
type: item
subject: Editorial
  topic: section
creator: Alfonsina Tripaldi
creator: Paula Santi Malnis
rights: Copyright (c) 2023 Alfonsina Tripaldi, Paula Santi Malnis https://creativecommons.org/licenses/by-nc/4.0
date: 2023-12-30
publication date: 2023-12-30
starting page: 93
ending page: 94

Diagenetic evolution of the Permian Tunas Formation, Claromecó Basin, Buenos Aires province, Argentina: its impact on porosity and reservoir characteristics
type: item
description: The foreland Claromecó Basin, located in the south-western sector of Buenos Aires province, Argentina, has a relevant economic and energetic interest due to the presence of coal layers contained in the Permian Tunas Formation, which might be considered effective source rock for gas resource generation. This study aims to reconstruct the diagenetic evolution of the Tunas Formation at the Claromecó Basin (PANG 0001 and PANG 0003 wells) and determine how the diagenesis affected the reservoir quality. To this purpose, core samples of the Tunas Formation were analysed using a combination of micro petrographic analyses (transmitted light, QEMSCAN, cathodoluminescence), fluid inclusions studies, and petrophysical methods (conventional core analysis, CCA). The analysed sedimentary successions are composed of sandstones interbedded with mudrocks, carbonaceous mudrocks, tuffs, and coals. Sandstones are medium- to fine-grained, framework-supported, and moderate-to-well-sorted. Authigenic minerals are calcite and laumontite, with minor proportions of quartz and feldspar overgrowths and clay minerals (illite, muscovite, and chlorite). Porosity is of secondary type, generated by fracturing and dissolution of feldspars and carbonate cement. Porosity determined by optical, QEMSCAN, and CCA analyses ranges from 0.1 to 4 %, with a permeability varying between 10-3 and 10-6 millidarcies. Fluid inclusion studies were performed in sandstone cements and calcite and quartz veins. Primary, pseudo-secondary, and secondary aqueous and organic fluid inclusions were recognized. Organic fluid inclusions show green and light blue fluorescence, which indicates the presence of hydrocarbons. Homogenization temperatures of fluid inclusions obtained from microthermometry studies range from 124 to 200 °C in cements and 110 to 230 °C in veins. These temperatures confirm a metagenesis stage for the Tunas Formation, within the wet to dry gas window. Given the petrophysical characteristics of the analyzed…
subject: Research Papers
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creator: María Belén Febbo
creator: Nora Cesaretti
creator: Silvia Omodeo-Salé
creator: Andrea Moscariello
creator: Antoine de Haller
creator: Natalia Fortunatti
creator: Giselle Choque
creator: Renata Tomezzoli
rights: Copyright (c) 2024 Maria Belen Febbo, Nora Cesaretti , Silvia Omodeo-Salé , Andrea Moscariello, Antoine de Haller , Natalia Fortunatti, Giselle Choque, Renata Tomezzoli https://creativecommons.org/licenses/by-nc/4.0
date: 2024-07-10
publication date: 2024-07-10
starting page: 65
ending page: 95

Sand pipes as potential indicators of seismicity in the Casa Grande Formation, northwestern Argentina
type: item
description: In fluvial deposits of the Casa Grande Formation (Middle Eocene), a suite of Soft Sediment Deformation Structures (SSDS) have been identified, the genesis of which could be associated with seismic movements (seismites). This formation has been linked to the early stages of evolution of the Andean foreland basin in the transition between the Puna and the Eastern Cordillera. This study focuses on describing and interpreting discordant structures understood as sand pipes and the processes related to their formation. These structures are characterized by an inverted funnel morphology and are distinguished by their metric-scale dimensions. Associated with the sand pipes, disturbed lamination, pillar and plate structures, clastic dikes, and load casts were recognized and described. Considering the characteristics of these structures, liquefaction and fluidization processes are interpreted as the formative mechanisms. Based on the deposit and structures characteristics, presence in restricted stratigraphic intervals, lateral continuity, vertical repetition, proximity to faults, and similarity to structures produced by recent earthquakes, seismic events are proposed as the triggering mechanism for the deformation.
subject: Research Papers
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creator: Mario Albertengo
creator: Cecilia del Papa
creator: Ayelén Lapiana
rights: Copyright (c) 2024 Mario Albertengo, Cecilia del Papa, Ayelén Lapiana https://creativecommons.org/licenses/by-nc/4.0
date: 2024-04-17
publication date: 2024-04-17

Fire effects on rock weathering in the North Patagonian Andean Range
type: item
description: Fire-induced rock exfoliation is a rapid mechanical weathering process characterized by an uneven heating and thermal expansion stress that causes the detachment of rock peels, flakes or spalls. We examined 18 granitoid erratic blocks on a gradient of fire severity in a burned inselberg near El Bolsón, during March 2023. Among them, 13 blocks showed fire spalling, producing 0.1 to 6 kg/m2 of sediment on rock surfaces with an average of 1.72 kg/m2. The incidence of fire spalling showed a more pronounced occurrence within areas of higher severity above dNBR 800. This study is the first mention of fire-induced weathering in the Patagonian Andes, which underlines the need to investigate the intricate relationship between forest fires and the denudation of vegetated outcrops in the region.
subject: Short Notes
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creator: Agustín Quesada
creator: Melina B. Paez
creator: Nicolás M. Bistolfi
creator: Ana P. Blazina
creator: Mariano M. Amoroso
rights: Copyright (c) 2024 Agustín Quesada, Melina B. Paez, Nicolás M. Bistolfi, Ana P. Blazina, Mariano M. Amoroso https://creativecommons.org/licenses/by-nc/4.0
date: 2024-07-10
publication date: 2024-07-10
starting page: 96
ending page: 102

Editorial
type: item
subject: Editorial
  topic: section
creator: José I. Cuitiño
creator: Giorgio Basilici
creator: M. Sol Raigemborn
rights: Copyright (c) 2023 José I. Cuitiño, Giorgio Basilici, M. Sol Raigemborn https://creativecommons.org/licenses/by-nc/4.0
date: 2023-07-12
publication date: 2023-07-12
starting page: 1
ending page: 2

Soil-geomorphic relationships in a northeastern Patagonian tidal salt marsh, Península Valdés, Argentina
type: item
description: Salt marshes ecosystems have been studied extensively based on the interaction between geo-morphological and geo-ecological processes, but a soil-geochemistry approach is currently unknown in Patagonia. This work was conducted in Riacho salt marsh, Patagonia, Argentina, and, its aim was to establish the soil-geomorphology relationship with a focus on geochemical analysis and vegetation changes (C3 vs. C4 photosynthesis pathway plants). The geochemical analysis was focused on sulfidic material occurrence and their potential acid generation, while the vegetation-geomorphology relationship was determined through the ?13C composition from soil organic matter. To achieve this, soil descriptions and laboratory analyses of soil samples were performed. Riacho salt marsh soils correspond to the Entisol Order and the Suborder Aquents. Soils corresponding to Sarcocornia perennis and Limonium brasiliense vegetation units were classified as Sodic Hydraquents, which were associated with tidal flats between Holocene beaches-ridges systems. On the other hand, the soil corresponding to the Spartina alterniflora vegetation unit was classified as Haplic Sulfaquents related to salt marsh lower levels, where waterlogging soil conditions favor the sulfidic materials formation. These soils are considered potential acid sulfate soils (PASS) due to the generation of sulfuric acid by oxidation processes. Consequently, extreme oxidation of these soils could release metals. The ?13C isotope composition of soil organic matter, in combination with the C/N ratio, indicates that the sandy C horizons from soils corresponding to high salt marsh levels would constitute pioneer salt marshes, which is consistent with the Holocene salt marshes development. The plant zonation model responds to ecological succession according to geomorphology evolution. However, future isotopic studies will be necessary to determine the contributions of different sources, both surface runoff of organic matter from contine…
subject: Special Issue
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creator: Ileana Ríos
creator: Pablo José Bouza
creator: Alejandro Bortolus
creator: Yanina Idaszkin
creator: Nicolás Scivetti
rights: Copyright (c) 2023 Ileana Ríos, Pablo José Bouza, Alejandro Bortolus, Yanina Idaszkin, Nicolás Scivetti https://creativecommons.org/licenses/by-nc/4.0
date: 2023-12-30
publication date: 2023-12-30
starting page: 95
ending page: 113

Origin and evolution of coastal lagoons from the pampean region: Mar Chiquita, Las Brusquitas, Reta (Buenos Aires province, Argentina)
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description: Low-lying coasts are specially conditioned for the origin and development of coastal lagoons. The Pampean region (Buenos Aires, Argentina) contains the surplus of a sea level fluctuation that occurred during the last 6000 years. This report studied three coastal lagoons at different stages of their evolution: Mar Chiquita coastal lagoon, Las Brusquitas estuarine lagoon, and the small coastal lagoon of Balneario Reta. The long-term evolution is considered in the case of Mar Chiquita and Las Brusquitas, while modern trends are also described for the Mar Chiquita silting problems and the urbanisation of the Reta village surrounding the lagoon. The study is based on radiocarbon datings, salinity analyses and sedimentological studies on both outcrops and piston cores. At Mar Chiquita coastal lagoon, a shallow open bay has been restricting since the Middle Holocene, causing the development of marshes and tidal flats between cheniers and regressive spits. Its evolution is therefore conditioned to high-energy events that reworked bioclastic sands (cheniers and regressive spits) and the silting of fine sediments. The sequence outcropping at the outlet of the Las Brusquitas creek extended temporally between 6190 and 2380 14C years BP; the estuarine lagoon was located at the outlet of two creeks. New outcrops exhumed and radiocarbon datings indicated this new interpretation of the site as an estuarine lagoon silted in the last 2000 years. The small estuarine lagoon (“microalbufera”) of Balneario Reta is another wetland flooded by the increase in water discharge due to artificial channels. Their connection to the sea depends on the effects of maximum tides and winds blowing from the south. The contents in diatom assemblages were interpreted as indicators of changes in salinity balances during the Late Holocene. Oligohaline specimens dominated at the three coastal lagoons; polihaline and mesohaline assemblages characterise some intervals at the Mar Chiquita and Las Brusquitas se…
subject: Research Papers
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creator: Federico I. Isla
creator: José Bedmar
creator: Camilo Vélez Agudelo
creator: Luis Cortizo
rights: Copyright (c) 2024 Federico Ignacio Isla, José Bedmar, Camilo Vélez Agudelo, Luis Cortizo https://creativecommons.org/licenses/by-nc/4.0
date: 2024-07-10
publication date: 2024-07-10
starting page: 1
ending page: 12

Recent disturbance events recorded in the sedimentary infill of Lago Guillelmo (Argentina): tephra falls and hydrogeomorphic processes
type: item
description: We studied two natural disturbances that affect the Parque Nacional Nahuel Huapi area: tephra fall events from Andean volcanoes and hydrogeomorphic processes within catchments related to heavy rains. We carried out a surface analysis, describing the main morphometric features of the selected watershed, informally called La Cantera watershed; analyzing satellite images and historical aerial photographs; looking for evidence of processes related to these disturbance events in the watershed and morphological changes in the alluvial fan generated over the delta. The subaqueous environment was analyzed through bathymetries, sediment cores, and Ground Penetrating Radar (GPR) profiles, taken in the distal deltaic environment of the watershed. In the sedimentary record of the lake, we identified 12 tephra layers deposited in the last 200 years, attributed to Cordón Caulle, Calbuco, and Osorno volcanoes. These were chronologically correlated with previously documented eruptions of these volcanic centers, using vitroclast morphology, mineral association, and stratigraphic position. We also identified 10 epiclastic layers corresponding to sediments with terrigenous components and terrestrial organic matter, interpreted as hyperpycnites. We assign two hyperpycnite deposits to a debris flow that occurred in the area in February 2015 that caused several damages and roadblocks, based on the stratigraphic position of these deposits in the cores, and the identification of sediments associated with this event on the lake surface in satellite images. After the correlation between the GPR radargram units with the lacustrine cores, we associated one major radar unit with a (1) tephra layer and (2) lobe-shaped morphologies, interpreted as a hyperpycnite deposits, located in front of the outflow of an abandoned river course. The results allow inferring a significant anthropic impact in the lacustrine record, as a result of the construction of Route 40 and gravel mining activities after 19…
subject: Special Issue
  topic: section
subject: Array
  topic: keywords
subject: Array
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subject: Array
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subject: Array
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subject: Array
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creator: Pablo Amat
creator: Gustavo Villarosa
creator: Débora Beigt
creator: Valeria Outes
creator: Julieta Cottet
creator: Lucia Inés Dominguez
creator: Alex Cottescu
creator: Andres Barbosa
rights: Copyright (c) 2023 Pablo Amat, Gustavo Villarosa, Débora Beigt, Valeria Outes, Julieta Cottet, Lucia Inés Dominguez, Alex Cottescu, Andres Barbosa https://creativecommons.org/licenses/by-nc/4.0
date: 2023-12-30
publication date: 2023-12-30
starting page: 163
ending page: 184