Journal of South American Earth Sciences最新文献

{"title":"Mineralogical characterization of fossil woods from the Las Cañas Formation (early Pliocene), Santiago del Estero, Argentina, mainly using SEM and EDX, XRD, FTIR and Confocal Raman spectroscopy","authors":"E. Baez ,&nbsp;A. Crisafulli ,&nbsp;A. Kanbour ,&nbsp;E. Figueredo","doi":"10.1016/j.jsames.2025.105679","DOIUrl":"10.1016/j.jsames.2025.105679","url":null,"abstract":"<div><div>This study conducted physicochemical and mineralogical characterization of fossil angiosperm woods, from Neogene fluvial sedimentary deposits of the Dulce River (Termas de Río Hondo Sector), Santiago del Estero Province, Argentina. Chemical and instrumental analyses demonstrated that the early Pliocene specimens comprise extensively mineralized silica polymorphs. In this work, X-ray diffraction (XRD) techniques combined with scanning electron microscopy (SEM) with backscattered electron detector (BSE) and spectroscopic techniques such as energy dispersive X-ray (EDX), confocal Raman (CRS) and Fourier transform infrared (FTIR) were applied. This research includes not only the physicochemical characterization of angiospermic logs, especially the indeterminate species of <em>Vitaceae</em> (<em>Vitaceoxylon</em> sp.) and <em>Menendoxylon mesopotamiensis</em>, but also studies the analysis of the regional geological environment that allows paleoenvironmental, paleoclimatic and paleobiogeographic inferences for the neogenic xylotaphoflora related to the outcrops of the Dulce River, in the transition between the Pampean Sierras of the Northwest (NW) and the basin of the Chaco-Pampean Plain, Argentina.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105679"},"PeriodicalIF":1.7,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716166","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":"Unraveling the water exchange dynamics of the Guarani aquifer system with underlying and overlying aquifers in Uruguay","authors":"Elias Hideo Teramoto ,&nbsp;Hendryk Gemeiner ,&nbsp;Gerardo Veroslavsky ,&nbsp;Hung Kiang Chang","doi":"10.1016/j.jsames.2025.105682","DOIUrl":"10.1016/j.jsames.2025.105682","url":null,"abstract":"<div><div>The Guarani Aquifer System (GAS) ranks among the world's largest aquifer systems, stimulating extensive research into its stratigraphy and hydrodynamic properties improving understanding into groundwater flow dynamics. Previous geochemical studies have concentrated on the hydrochemical and isotopic characteristics of the GAS, highlighting the significant role of progressive rock-water interactions in shaping its hydrochemical evolution. This study builds on previous works by incorporating hydrogeochemical and isotopic data from both the overlying Serra Geral Aquifer System (SGAS) and the underlying Paleozoic aquifers (Pre-GAS), coupled with geochemical simulations, to provide a more holistic understanding of GAS dynamics in Uruguay. Our findings reveal that the GAS is intricately interconnected with both the SGAS and Pre-GAS, forming a complex, multilayered aquifer system characterized by significant groundwater exchange among these units. Contrary to expectations, the GAS outcrop zone functions primarily as a discharge area due to its topographical position and proximity to the Tacuarembó River, with recharge occurring mainly through leakage from the SGAS. These results challenge the prevailing groundwater circulation models focused solely on the GAS and carry important implications for groundwater management, numerical flow modeling, and the estimation of groundwater residence times.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105682"},"PeriodicalIF":1.7,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633500","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":"Exploring relationships between GNSS time series, terrestrial water storage and geological features in Brazil","authors":"Yellinson de Moura Almeida ,&nbsp;Giuliano Sant'Anna Marotta","doi":"10.1016/j.jsames.2025.105686","DOIUrl":"10.1016/j.jsames.2025.105686","url":null,"abstract":"","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"164 ","pages":"Article 105686"},"PeriodicalIF":1.7,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614835","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":"Dynamic coastal vulnerability index: A machine learning approach to predict future impacts of climate change and human activity on coastal environments","authors":"M. Vadivel ,&nbsp;Ar S. Sundar ,&nbsp;Venkataradhakrishnamurty ,&nbsp;M. Soundararajan ,&nbsp;Dineshkumar Rajan ,&nbsp;V. Priya","doi":"10.1016/j.jsames.2025.105692","DOIUrl":"10.1016/j.jsames.2025.105692","url":null,"abstract":"<div><div>Coastal regions are increasingly vulnerable to the compounded impacts of climate change and human activities, necessitating the development of more dynamic and predictive assessment frameworks. This study introduces a Dynamic Coastal Vulnerability Index (DCVI), employing machine learning techniques to forecast future changes in coastal vulnerability along the shoreline of Mazatlán, Mexico. By integrating physical, environmental, and socio-economic indicators, the model utilizes a Random Forest algorithm to assign weights objectively and capture complex, non-linear relationships among variables. Initial vulnerability classification was performed using ranking and weighted overlay methods, subsequently refined through machine learning-based optimization to enhance predictive accuracy. The spatial analysis indicates that, out of a total area of 3068.50 km², approximately 56.06 % of the region is classified as moderately vulnerable, 27.71 % as low vulnerability, 5.38 % as very high vulnerability, 3.59 % as high vulnerability, and 7.28 % as very low vulnerability. These results demonstrate a heterogeneous distribution of vulnerability across the study area, emphasizing the urgent need for targeted adaptation and resilience strategies. The findings highlight the advantages of dynamic, machine learning-enhanced methodologies over conventional static models for coastal vulnerability assessments. The DCVI framework developed in this study offers an advanced decision-support tool for policymakers, urban planners, and coastal managers aiming to mitigate the anticipated impacts of climate change and anthropogenic pressures on coastal environments. The primary intention of this research is to develop a dynamic, predictive model for coastal vulnerability assessment and to inform adaptive coastal management strategies under future environmental and socio-economic scenarios.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105692"},"PeriodicalIF":1.7,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633498","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":"Using environmental conservation units as reference for evaluating contamination in river basins","authors":"Paulo Roberto Bairros Da Silva ,&nbsp;Camilo Jose Viera Iglesias ,&nbsp;Denise Parizotto ,&nbsp;Lurian Aparecida Domingos Da Cruz ,&nbsp;Valderi Dressler ,&nbsp;Jean Paolo Gomes Minella ,&nbsp;Danielle Caroline Schnitzler ,&nbsp;Frederico Fabio Mauad","doi":"10.1016/j.jsames.2025.105688","DOIUrl":"10.1016/j.jsames.2025.105688","url":null,"abstract":"<div><div>Risk assessment of sediment quality relies on using local references as a guiding criterion. However, there are knowledge gaps regarding the criteria for defining (choosing) reference sites free from contamination on the river basins scale. Under this perspective, this study establishes appropriate baselines (backgrounds) for the Várzea River basin - RS, using different criteria based on the average concentrations of the elements Al (10539.4–12454.7 mg kg⁻¹), Ba (6.0–62.0 mg kg⁻¹), B (23.0–140.4 mg kg⁻¹), Ca (990.0–3859.1 mg kg⁻¹), Co (9.6–11.1 mg kg⁻¹), Cu (36.3–234.2 mg kg⁻¹), Fe (46091.0–92750.9 mg kg⁻¹), Li (136.4–147.8 mg kg⁻¹), Mg (149.9–500.2 mg kg⁻¹), Mn (336.4–1894.1 mg kg⁻¹), K (557.0–748.5 mg kg⁻¹), Ag (0.0–70.5 mg kg⁻¹), Na (70.5–1447.4 mg kg⁻¹) and Sr (8.2–1344.0 mg kg⁻¹), which are common in the region's soils, determined from samples collected in highly preserved environmental conservation areas. The study's background results demonstrate that the use of inadequate and/or non-representative local references as an indicator of environmental quality can lead to either overestimation or underestimation of environmental contamination. The Robustness Method proved to be most suitable for assessing environmental quality in this hydrographic basin.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105688"},"PeriodicalIF":1.7,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633499","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":"A new pterosaur mandible from the Lower Cretaceous of Brazil, and its implications on the taxonomy of the genus Anhanguera (Pterosauria, Anhangueridae)","authors":"Lucas C. Piazentin ,&nbsp;Bruno A. Navarro ,&nbsp;R.V. Pêgas ,&nbsp;Alberto B. Carvalho ,&nbsp;Hussam Zaher","doi":"10.1016/j.jsames.2025.105684","DOIUrl":"10.1016/j.jsames.2025.105684","url":null,"abstract":"<div><div>Pterosaurs are extinct archosaurs specialized in an active flight lifestyle, with more than half of the species described classified as pterodactyloids. Much of the anatomical knowledge on pterodactyloids originated from specimens collected in the Cretaceous deposits of South America. The Araripe Basin in Northeastern Brazil holds a remarkable record, particularly within the Aptian–Albian Crato and Romualdo formations, from which numerous specimens have been assigned to the genus <em>Anhanguera</em>. To date, three species from this unit are recognized as valid based on relatively complete specimens: <em>A. blittersdorffi</em>, <em>A. piscator</em>, and <em>A. spielbergi</em>. Here, we describe a new anhanguerid specimen from the Romualdo Formation, comprising an almost complete lower jaw and elements of the hyoid apparatus. MZSP-PV 368 is assigned to <em>Anhanguera</em> based on the presence of a well-developed ventral mandibular crest, specific alveoli count, and tooth morphology. The specimen has an overall shape of the crest that is unique among ornithocheiromorphs and supports its referral to <em>A. robustus</em>, a species recently considered a <em>nomen dubium</em>. Phylogenetic and morphometric analyses of MZSP-PV 368 further support its affinity with <em>A. robustus</em>, highlighting the diagnostic value of mandibular crest morphology in anhanguerid taxonomy. These findings indicate that <em>A. robustus</em> represents a diagnosable taxon, herein recognized as a valid species. However, the taxonomy of the genus <em>Anhanguera</em> remains unresolved and will require additional specimens with a greater degree of anatomical overlap for further clarification.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105684"},"PeriodicalIF":1.7,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662129","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":"Effects of floating macrophytes on open-water evaporation in a Brazilian tropical reservoir","authors":"Italo Sampaio Rodrigues ,&nbsp;Carlos Alexandre Gomes Costa ,&nbsp;Adunias dos Santos Teixeira ,&nbsp;Iran Eduardo Lima Neto ,&nbsp;Fernando Bezerra Lopes ,&nbsp;José Carlos de Araújo","doi":"10.1016/j.jsames.2025.105683","DOIUrl":"10.1016/j.jsames.2025.105683","url":null,"abstract":"<div><div>This paper aims to estimate the open-water evaporation (from 1990 to 2021) in an urban reservoir in Brazil and assess the relationship between floating macrophyte coverage (MC) and open-water evaporation, as well as their spatial variability. The Surface Energy Balance System for Water (AquaSEBS) provided similar (root mean square error of 0.5 mm/day) results to reference measurements of class A pan (correction coefficient of 0.7). The discharge of sewage into this urban tropical reservoir resulted in a portion of this reservoir being covered by floating macrophytes. During the study period, positive trends of floating MC area were observed. The days with floating macrophytes depicted higher spatial variability over the open-water evaporation. Furthermore, MC was negatively correlated with the open-water evaporation flux (R² = 0.65) and led on average to a 17 % reduction (varying from 9 % to 35 %) in the estimated evaporation rate in the free water surface. Overall, the results of this study demonstrate the usefulness of remote sensing products to estimate reservoir open-water evaporation and outline the need to better understand the relationship between MC and reservoir open-water evaporation in tropical and semi-arid areas.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"164 ","pages":"Article 105683"},"PeriodicalIF":1.7,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144614836","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":"Review of the ideas regarding the evolution of the Ventania System and its tectonic relationship with the Río de la Plata Craton and Patagonia","authors":"Carlos A. Ballivián Justiniano ,&nbsp;Francisco I. Lugo ,&nbsp;Sebastián Oriolo","doi":"10.1016/j.jsames.2025.105678","DOIUrl":"10.1016/j.jsames.2025.105678","url":null,"abstract":"<div><div>The Ventania System, composed of a Tonian–middle Cambrian crystalline basement (i.e., Sauce Chico Complex, SCC) and a late Cambrian–Cisuralian sedimentary cover, has been a key region in the postulation of hypotheses on the drift of South America and the collision of Patagonia with the Río de la Plata Craton (RPC). This work compiles and statistically analyzes the U–Pb and Lu–Hf zircon data of the Ventania System. Through the application of multidimensional scaling analysis and Monte Carlo mixture modelling, results highlight the RPC, the SCC, the Eastern Pampean Ranges, and the North Patagonian Massif (NPM) as the main source areas. One of the main differences between the model presented here and that of previous authors is the greater significance of the SCC as a source, the lesser importance of the Eastern Pampean Ranges, and the role of the NPM as a source throughout the Paleozoic. The latter may be the result of age similarities of zircon populations between the SCC and the basement of the northeastern NPM. This and the isotopic data suggest a correlation between both basements as part of the southern accretionary margin of the RPC during the late Ediacaran–early Cambrian and reinforce the hypothesis of an African origin of at least part of northern Patagonia via the Sierra de la Ventana Shear Zone (SVSZ), which is located immediately south/southwest of the Ventania System and constitutes the southern border of the RPC. The SVSZ would have been decisive in the development of the Paleozoic Ventania basin, interpreted here as an episutural basin, and in the subsequent Gondwanide deformation that affected the entire system.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105678"},"PeriodicalIF":1.7,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144678806","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":"Impacts of climate change on coastal erosion and marine flooding in Rio de Janeiro city, Brazil","authors":"João Wagner Alencar Castro ,&nbsp;Willian Cruz Gouvea Junior ,&nbsp;Daniel Fernandes ,&nbsp;Caique Lima Cabral ,&nbsp;Guilherme Tenorio Smith da Costa ,&nbsp;Frederico Maciel Pinheiro Sampaio de Miranda ,&nbsp;Julia Sales Serrano ,&nbsp;Karem Moreno Carvalho ,&nbsp;Sergio Bezerra Lima Junior","doi":"10.1016/j.jsames.2025.105680","DOIUrl":"10.1016/j.jsames.2025.105680","url":null,"abstract":"<div><div>The environmental impact of climate change on shoreline erosion and marine flooding pose major challenges for public managers, especially in large coastal cities in Brazil. A significant portion of coastal cities have been protected by riprap structures against natural disasters and also by human action. Increasing storm surges observed in virtually all seasons of the year will allow higher waves to reach avenues and urban areas more frequently, requiring public managers to expand coastal protection structures. This article identifies and quantifies areas subject to beach retreat (coastal erosion) on open-ocean beaches in Rio de Janeiro city. The procedures consisted of acquiring images with moderate spatial resolution of 30.0 m from the sensors of the Landsat 5 (TM), Landsat 7 (ETM+), Landsat 8 (OLI) and Landsat 9 (OLI-2) satellites, referring to the years 1984, 1994, 2004, 2014, and 2023, supplemented by information on tides and wave climate obtained at the time of satellite passage. Results obtained suggest varied granulometric patterns, an increase in the number of storm waves and processes of stability and erosion shoreline in the last 40 yrs. The adoption of measures to replenishment the sediment stock on eroding beaches is necessary due to ongoing climate change.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105680"},"PeriodicalIF":1.7,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653122","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":"Insights into the magmatic and metallogeneticevolution of the Morro del Cobre porphyry copperdeposit from fluid inclusions and lead isotope signatures","authors":"María Verónica Bastias Torres ,&nbsp;María Celeste D’Annunzio ,&nbsp;Lorena C. Previley ,&nbsp;Nora A. Rubinstein","doi":"10.1016/j.jsames.2025.105685","DOIUrl":"10.1016/j.jsames.2025.105685","url":null,"abstract":"<div><div>The Morro del Cobre porphyry (Cu-Mo-Au) deposit, genetically linked to the upper Miocene magmatism (∼10–9 Ma), is located over the Pampean flat-slab segment (28–33°S) in San Juan province (Argentina). The analysis of the different vein systems provided insights into the physical and chemical evolution of the hydrothermal fluids responsible for the formation of this deposit. The potassic alteration is intense to moderately penetrating in veins (A-type veins -Subtypes 1 and 2-, EB-type, and EBT-type). The fluid inclusion study determined that Type III inclusions in A1 veinlets have salinities of 40.6–56.1 wt% NaCl eq. and homogenization temperatures from 365 to 472 °C. In A2 veinlets, salinities range from 37.4 to 52.2 wt% NaCl eq., with homogenization temperatures between 343 and 472.5 °C. A transitional hypogenic mineralization stage between potassic alteration and phyllic alteration is represented by B veinlets. Type III fluid inclusions show homogenization temperatures ranging from 315.2 to 397 °C and salinities of 40.6–46.78 wt% NaCl eql. Moderate phyllic alteration is extensively distributed in the area and occurs pervasively and in D-type veinlets, overprinting the potassic alteration. A supergene alteration event is widely distributed in the area. It occurs pervasively, overprinting the potassic and phyllic alteration with an assemblage of limonite, malachite, chrysocolla, turquoise and azurite, and covellite and chalcocite replacing chalcopyrite. The Pb isotopic composition indicates a genetic relationship between the ore minerals of this deposit and the magmatism preceding the porphyry-type mineralization in the area. The mineralizing magmas of Morro del Cobre involve an older Pb from the Grenvillian basement, evidenced by the presence of medium to high-grade metamorphic xenoliths and inherited zircons. Furthermore, there is probably a Pb contribution from Gondwanic magmas, as these are the principal constituent of the Cordillera Frontal. The assimilation of fertile Gondwanan basement material by the Miocene magmatism at Morro del Cobre plays a crucial role in the formation of a productive mineral deposit.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"164 ","pages":"Article 105685"},"PeriodicalIF":1.7,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605075","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}