Journal of South American Earth Sciences最新文献

{"title":"Streamflow spatio-temporal variability of water stable isotopes and hydrochemical properties in a semiarid mountain catchment in Northwestern Argentina","authors":"Marcos Macchioli-Grande ,&nbsp;Gimena Uran ,&nbsp;Mariano Larrovere ,&nbsp;Cecilia Echegoyen ,&nbsp;María Poca","doi":"10.1016/j.jsames.2025.105717","DOIUrl":"10.1016/j.jsames.2025.105717","url":null,"abstract":"<div><div>Mountain catchments are critical sources of water. Particularly in semiarid regions, where precipitation is exceeded by potential evapotranspiration, mountain catchments are important water reservoirs for the population settled in the nearby lowlands. This study investigates the spatio-temporal variability of water stable isotopes and hydrochemical properties in the semiarid Huaco catchment, located in the Sierras Pampeanas of the Andean foreland in Northwestern Argentina. Stream water samples were collected across four sub-catchments along an altitudinal gradient. The results indicate that electrical conductivity and chloride concentrations increase downstream (from 148.1 to 307.2 μS cm⁻¹ for the former and from 17.7 to 46.4 ppm for the latter) while water stable isotopic composition (δ¹⁸O and δ²H) remain uniform across the altitudinal gradient (with averages of −5.1 ‰ and −24 ‰, respectively). These spatial variations are indicative of increasing evaporative concentration with decreasing altitude, also exhibiting decreasing streamflow with decreasing altitude. Moreover, water is diluted (with TDS up to 175 mg L⁻¹), alkaline (pH = 8.2–8.5), and transitions from bicarbonate-mixed to bicarbonate-sodium types downstream. Within the year 2022, major ions showed slight seasonal variation. Conversely, water stable isotopes remained constant within the temporal scale. This suggests groundwater as a uniform source feeding streamflow. Additionally, concentration-streamflow relationships of electrical conductivity and chloride suggest predominantly chemostatic behavior, highlighting limited variability in solute concentrations despite changes in streamflow. This integrative isotopic, hydrochemical, and hydrometric approach provides insights into the hydrological dynamics in this semiarid mountain catchment, improving the understanding of hydrological processes in these environments.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105717"},"PeriodicalIF":1.5,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763970","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":"Introduction to the scientific ideas of Professor Victor A. Ramos on the Proterozoic and Paleozoic geotectonic evolution of the Argentinean-Chilean Andes: origin, evolution, and alternatives","authors":"Nemesio Heredia ,&nbsp;Andrés Folguera","doi":"10.1016/j.jsames.2025.105713","DOIUrl":"10.1016/j.jsames.2025.105713","url":null,"abstract":"<div><div>Through a brilliant and proliferous career of 60 years, Victor A. Ramos has discussed aspects concerning the evolution of the Andes' structure, their basement, associated magmatism, basin evolution, geotectonic context, seismicity, and gravimetry. Deep thrust ramps associated with Andean structuration were interpreted by Ramos as due to crustal inheritance, either associated with Triassic extensional structures related to Pangea breakup such as lithospheric structures associated with Paleozoic accretions against the southwestern margin of Gondwana (ancient Rio de la Plata craton) from Early Cambrian onwards. Thus, in conjunction with embryonic proposals of other groups, a series of proposed amalgamated continental blocks were defined that explained the development of Paleozoic sutures, magmatic and orogenic belts, associated with ancient oceanic subductions and continental collisions: The Early Cambrian Pampean collision, the re-accretion of the southern part of the Arequipa-Antofalla terrane (Arequipa microplate) and the Cuyania collision in late Ordovician times, the Late Devonian accretion of the Chilenia terrane, the accretion of the Mejillonia and Pichidangui terranes and the collision of Patagonia in late Carboniferous times. Early hypotheses have diversified through time in multiple lines of scientific research taken from several scientific groups all across the world. We discuss their development in fertile ulterior scientific fields, their growth, and eventual transformation. Victor Ramos' scientific career exemplifies more than half a century of scientific growth in the tectonic evolution knowledge of the Andes and all the South America in general, and the description of his scientific work exposes achievements and limitations to his models that have allowed the birth of new theories. The tectonic plate paradigm was a profound dislocation of scientific ideas concerning the evolution of the Earth's crust. In Argentina, as in many other regions, this change triggered a complete revision of classical local geology and its re-interpretation, in which Victor Ramos was a pioneer.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105713"},"PeriodicalIF":1.5,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048996","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":"Spatial-spectral feature extraction using multispectral linear unmixing for land use land cover change detection","authors":"Ricardo Franco ,&nbsp;Maria C. Torres-Madronero ,&nbsp;Maria Casamitjana ,&nbsp;Tatiana Rondon","doi":"10.1016/j.jsames.2025.105722","DOIUrl":"10.1016/j.jsames.2025.105722","url":null,"abstract":"<div><div>Multispectral imagery is essential in remote sensing for the Land Use Land Cover (LULC) classification task. However, open-access platforms like Landsat and Sentinel offer low spatial resolution, causing mixed pixel issues that affect classification accuracy. This paper proposes a representation space that integrates spectral and spatial information using linear unmixing. The representation space is used to train a supervised classifier, and then classification maps are employed in LULC change detection and quantification. The proposed framework for LULC change detection allows the use of satellite images with different spatial and spectral resolutions. The representation space is tested on multispectral versions of benchmark datasets (Salinas, Indian Pines, Kennedy Space Center, and Botswana), obtaining classification accuracies up to 96 %. The proposed representation space significantly improves classification accuracy (up to 11 %) and outperforms existing multispectral classification approaches in the literature. Finally, the LULC change detection framework is tested on a time series of Landsat 8 and Sentinel-2 images corresponding to a drainage basin located in the eastern region of Antioquia, Colombia. The main advantage of this framework is that it does not modify the spatial resolution of the images in the dataset, favoring the integration of images from multiple sensors and proving useful for change detection in regions with limited data. The proposed framework for LULC change detection achieved an accuracy of 90 %.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105722"},"PeriodicalIF":1.5,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144766995","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":"Microorganisms on siliceous-speleothems: example from sandstone caves, Brazil","authors":"Cintia Fernandes Stumpf ,&nbsp;Matheus Denezine ,&nbsp;Paola Ferreira Barbosa ,&nbsp;Sérgio Leandro de Vieira Toledo ,&nbsp;Beatriz Bachega Groppo ,&nbsp;Tulio Gabriel Ramos Ribeiro","doi":"10.1016/j.jsames.2025.105711","DOIUrl":"10.1016/j.jsames.2025.105711","url":null,"abstract":"<div><div>This study investigates siliceous speleothems by characterizing their macro- and microscopic features in caves formed within the Botucatu Formation, Paraná basin, Brazil. The analyzed speleothems consist of aerial coralloids composed of amorphous opal and detrital quartz grains, with biological components such as microbial-like filaments and diatoms. Two centric diatoms morphotypes are reported: <em>Orthoseira</em> sp. and Gen. 1 sp.1 and also a possible pennate species. Whereas diatom assemblage is confined to the photic and twilight zones, microbial filaments are reported both within these zones in addition to environments with limited sunlight exposure. The presence of biofilms and diatoms may increase local pH, facilitating silica dissolution and reprecipitation processes that contribute to speleothem formation. These caves are cataloged as geosites within the Corumbataí Geopark project, a pioneering initiative aimed at becoming the first geopark in the São Paulo State. This research enhances the first report of microbial assemblage in association with siliceous speleothems from the Serra de Itaqueri caves in the São Paulo State. In addition, understanding the biochemical processes that influence the development of siliceous speleothems in quartzose lithologies is crucial for deciphering their genesis mechanisms and potential environmental implications. All these dynamics involved in these caves highlight its relevance as a strategic geosite for paleoenvironmental, ecological, and conservation studies.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105711"},"PeriodicalIF":1.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712868","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":"New localities with Pleistocene mammals from the Department of Chuquisaca (Bolivia)","authors":"Alfredo E. Zurita ,&nbsp;Carlos A. Luna ,&nbsp;Francisco Cuadrelli ,&nbsp;Daniel Barasoain ,&nbsp;Ricardo H.A. Gómez ,&nbsp;Omar Medina ,&nbsp;Ángel R. Miño-Boilini","doi":"10.1016/j.jsames.2025.105691","DOIUrl":"10.1016/j.jsames.2025.105691","url":null,"abstract":"<div><div>Since the XIX century, the mammalian palaeofauna that inhabited the Pleistocene (ca. 2.6–0.0011 Ma) of South America is well known in several regions of this subcontinent, especially in the lowlands and at high latitudes. However, there is an imbalance in our knowledge of the diversity achieved by this palaeofauna, especially in the highlands of the current territory of Bolivia, known mainly from the Tarija Valley. With the aim of improving this situation, this paper presents and describes new fossil localities yielding Pleistocene mammals from the northern Department of Chuquisaca, in the Eastern Cordillera and Subandean geological provinces (ca. 2500<em>–</em>3500 m.a.s.l.). These localities include Sucre (S), Yampárez (Ya), Yotala (Yo), Redención Pampa (Rp), Potolo (P), Quila Quila (Q), Maragua (M), and Padilla (Pa), from which eight taxa have been identified: Xenarthra: <em>Panochthus</em> sp. (Rp, Ya), <em>Glyptodon jatunkhirkhi</em> (Yo, Rp), <em>Pampatherium</em> sp. (Rp), <em>Tolypeutes</em> cf. <em>T. matacus</em> (Rp), <em>Megatherium</em> sp. (P); Perissodactyla: <em>Equus</em> sp. (Yo, Rp, Q, M); Artiodactyla: <em>Lama guanicoe</em> (Rp); Proboscidea: <em>Cuvieronius hyodon</em> (Rp). The results show that so far <em>G. jatunkhirkhi</em> is endemic to the Eastern Cordillera and Subandean ranges, while it is reported the first Pleistocene record of <em>Tolypeutes</em> (Chlamyphoridae) for Bolivia, previously restricted to the Early Holocene, in addition to the first mandibular remains of <em>G. jatunkhirkhi</em>, which allows a better characterization of this species. Overall, the recognized assemblages suggest the presence of open and arid/semiarid environments, taking into account the presence of two living sensitive species, i.e. <em>Tolypeutes T.</em> cf. <em>matacus</em> and <em>L. guanicoe</em>. The large number of specimens recorded shows the high fossil potential of some localities in northern Chuquisaca.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105691"},"PeriodicalIF":1.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711788","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":"Geochemical processes influencing As distribution in waters associated with volcanic-hydrothermal systems: A case study of Coconucos volcanic chain-Puracé volcano, Colombia","authors":"Edgar Omar Almeida Miranda ,&nbsp;Claudio Inguaggiato ,&nbsp;Luisa Fernanda Meza Maldonado ,&nbsp;Loïc Peiffer ,&nbsp;Benedetto Schiavo ,&nbsp;Gilles Levresse","doi":"10.1016/j.jsames.2025.105716","DOIUrl":"10.1016/j.jsames.2025.105716","url":null,"abstract":"<div><div>This study mainly combines hydrogeochemical and geochemical modelling approaches to elucidate the roles of mineral equilibria, water-rock interaction and fluid mixing processes, in controlling arsenic (As) mobility in eight thermal springs of the Coconucos volcanic chain - Puracé volcano in Colombia. Three distinct water groups were identified based on physico-chemical parameters and chemical composition. Group 1, near-neutral SO₄-Cl-HCO₃ waters with temperatures ranging from 54.8 to 73.3 °C, showed moderate As concentrations of 3.4 and 126.2 ppb. Waters of Group 1 are the only ones partially equilibrated, with reservoir temperatures from 118 to 226 °C estimated through solute geothermometers. Geochemical equilibrium modelling performed using PHREECQ software, allowed us to propose that As concentrations could be controlled by iron (oxyhydr)oxides at the outlet temperature and by the precipitation of sulfide minerals under higher H₂S conditions. Group 2, acid-SO₄ waters (pH 1.7–2.3) with the lowest temperatures (23.8–44.7 °C), displays As concentrations from 2.1 to 57.5 ppb and near isochemical dissolution of local andesite rock. Low As in most Group 2 waters are likely due to the dilution caused by mixing thermal water with cold water. PHREEQC simulation reveals Fe and Cu sulfides oversaturation at elevated H₂S, potentially contributing to As depletion in waters. Group 3, acid SO₄-Cl waters with pH from 2.3 to 3.6 and the highest temperatures (80.4–81.6 °C), contained the highest As concentrations (380.8–987.5 ppb). Hypotheses for such enrichment are intense water-rock interaction, As-rich mineral dissolution, and minimal secondary mineral precipitation, as evidenced by PHREEQC saturation index results.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105716"},"PeriodicalIF":1.5,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144780960","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":"Multicriteria geospatial analysis for prioritizing soil erosion risk areas in a reservoir-contributing watershed","authors":"Vinicius Soares Campos,&nbsp;Tárcio Rocha Lopes ,&nbsp;Mateus de Oliveira Macedo,&nbsp;Fernando Simões Santos,&nbsp;Joyce Alchapar Silva,&nbsp;João Paulo Francisco,&nbsp;Fabricio Leite","doi":"10.1016/j.jsames.2025.105714","DOIUrl":"10.1016/j.jsames.2025.105714","url":null,"abstract":"<div><div>Soil erosion is a serious threat to sustainable land use management, making the identification of erosion-prone areas increasingly important. This study aimed to identify areas with riska to soil erosion in the Piquiri River basin, a significant tributary of the Paraná River and a key contributor to the Itaipu Hydroelectric Plant reservoir. A Multi-Criteria Analysis (MCA) integrated with geospatial techniques was used to map areas most susceptible to erosion. Several factors were considered: topography, land use and cover, soil erodibility, landslide susceptibility, proximity to rivers, time of concentration, and pasture quality. The criteria were analyzed using the Analytic Hierarchy Process (AHP), which allowed for weighting the relative importance of each factor based on expert consultation. The factors were combined using two multi-criteria methods: Weighted Linear Combination (WLC) and Ordered Weighted Averaging (OWA). The maps indicated that the highest erosion risk areas are mainly concentrated in the upper and middle parts of the basin, associated with steep slopes and degraded pastures. Furthermore, it was found that regions close to rivers also presented high priority for intervention. The OWA method, by varying the level of risk and compensation, made it possible to simulate different decision-making scenarios. The methods were compared with MUSLE and similarity was verified between the priority areas estimated by multicriteria analysis and soil loss. The study concludes that multicriteria techniques, integrated with geospatial tools, are effective in identifying priority areas for intervention, supporting soil conservation and erosion mitigation actions.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105714"},"PeriodicalIF":1.5,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720850","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":"Spatio-Temporal variability of CO2 efflux from stony soil under a seasonally dry tropical forest","authors":"Renato Francisco da Silva Souza ,&nbsp;Vânia da Silva Fraga ,&nbsp;Bruno de Oliveira Dias ,&nbsp;Jhony Vendruscolo ,&nbsp;Emanoel Lima Martins ,&nbsp;Walter Esfrain Pereira ,&nbsp;Victor Junior Lima Felix ,&nbsp;Rodrigo Santana Macedo ,&nbsp;Salomão de Sousa Medeiros ,&nbsp;Milton Cesar Costa Campos","doi":"10.1016/j.jsames.2025.105712","DOIUrl":"10.1016/j.jsames.2025.105712","url":null,"abstract":"<div><div>Quantifying the variability of soil CO₂ efflux (SCE) in stony soils, such as the Leptosol of the Brazilian semi-arid region is essential to obtain accurate measurements of SCE and improve its global estimate. The objective of our study was to assess the temporal and spatial variability of the SCE in a Caatinga forest. The SCE was measured at 42 randomly selected sampling points in a 0.72 ha plot. The average SCE varied from 0.47 to 4.14 μmol of CO₂ m⁻² s⁻¹ in a dry and wet season, respectively. The temporal variability of SCE is explained by 93 % volumetric soil water content, while soil temperature explained 52 % independently. The non-linear relationship between volumetric soil water content and soil temperature explains 87 % of the variability. The autocorrelation spatial distance of SCE oscillated from 5.7 to 64.3 m and was smaller during the wet season. The spatial variability of SCE is related to SOC, C:N, pH, clay, volumetric soil water content, and soil temperature, but the type of relationship differs with season. The temporal variability of SCE is mainly controlled by the volumetric soil water content. To quantify SCE, a distance between points greater than 64.3 m must be adopted for the measurements to be considered statistically independent. Individually, soil attributes and environmental variables explain some SCE spatial variability, especially in the dry season. Landscape heterogeneity linked to rock fragments, Leptosols, and microtopography modulates SCE by altering moisture, temperature, and organic matter. Given the complexity of these interactions, future studies should account for such variability in Caatinga stony soils.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105712"},"PeriodicalIF":1.5,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749196","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":"Big chill is hard to kill but it is time to move on - A comment on Faria et al., “3,500 years BP: The last survival of the mammal megafauna in the Americas”","authors":"João P.G. Machado ,&nbsp;Rachel Motta Kurtz ,&nbsp;Fernando A.S. Fernandez","doi":"10.1016/j.jsames.2025.105709","DOIUrl":"10.1016/j.jsames.2025.105709","url":null,"abstract":"","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105709"},"PeriodicalIF":1.7,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711789","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":"Geomorphological evidence of a historical Landslide-dammed Lake Outburst Flood in the Cajón del Bayo basin, Southern Central Andes (36°S)","authors":"Mariana Correas-Gonzalez ,&nbsp;Stella M. Moreiras ,&nbsp;Carolina Lauro ,&nbsp;Pilar Jeanneret","doi":"10.1016/j.jsames.2025.105710","DOIUrl":"10.1016/j.jsames.2025.105710","url":null,"abstract":"<div><div>Landslide dammed lakes are created when mass movements block river valleys, posing potential hazards in the form of Landslide-dammed Lake Outburst Flood (LLOF). In the Southern Central Andes (SCA) of Argentina (36°S), a rock avalanche dammed the Cajón del Bayo basin in 1986, creating Baya Lake. This study reconstructs the historical evolution of the basin, focusing on key geomorphological changes including the rock avalanche, lake formation and subsequent outburst flood. The analysis included: a) a geomorphological mapping, identification of outburst flood deposits and remote sensing of landscape evolution; b) sedimentological description of landslide facies and lake-level variations; c) landslide-dam characterisation and stability assessment; and d) a hydrometeorological analysis of temperature and precipitation to contextualise the LLOF event. Results show that a 4.7 hm³ rock avalanche impounded the Baya Lake. Geomorphic stability indices yielded contrasted results: while one classified the dam as stable, another indicated instability. Ultimately, the dam collapsed, triggering a LLOF that released 0.14 hm³ of water from the lake and 0.3 hm³ of sediments eroded from the dam, exposing its internal structure. Although geomorphic impacts were evident immediately downstream the lake, the event was not detected at the nearest gauging station, and a regional flood frequency analysis indicate low probability of occurrence of the empirically estimated peak discharge. This highlights how LLOFs occurred in remote areas may go unnoticed and how the increased discharge from small tributaries, though significant locally, can be attenuated in larger rivers. These findings underscore the importance of identifying and studying LLOFs at both local and regional scales in the SCA, where such events are underreported and may differ from global cases.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105710"},"PeriodicalIF":1.5,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724101","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}