Journal of South American Earth Sciences最新文献

{"title":"Water quality modulations under influence of rainfall and land cover in a mountain basin in southeast Brazil","authors":"Felipe Soter de Mariz e Miranda,&nbsp;André de Souza Avelar","doi":"10.1016/j.jsames.2025.105403","DOIUrl":"10.1016/j.jsames.2025.105403","url":null,"abstract":"<div><div>In the context of climate change, there are projections of an increase in storm occurrence and larger periods of drought that threaten water resources for human supply and ecosystems in South America. Based on this problem, this study aimed to understand how rainfall affects different water quality parameters and its relationship with changes in land cover. To this end, rainfall data were cross-referenced with water quality monitoring, and it was compared at two sampling points on the Rio Preto: upstream and downstream from a human settlement (Maromba District). The parameter thermotolerant coliforms was the parameter that showed the most divergence between the two sampling points, which often exceeded Brazilian legislation limits for supply and recreational use, and their variability over time was not related to rainfall. Dissolved oxygen and nitrates were the most correlated parameters with rainfall. Turbidity increases correlated to rainfall only downstream, being the parameter with the greatest difference between points in response to rain. However, the parameters that correlated in some way with rainfall remained within satisfactory values in the Maromba District. We believe that the virtual absence of agriculture in the basin is the key factor for maintaining satisfactory values of eutrophic parameters downstream, but it is noteworthy that human activity linked to tourism threatens water quality due to coliform contamination.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105403"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349585","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":"Thermal conductivity of igneous rock cores estimated from shallow wells drilled within the Las Tres Vírgenes volcanic complex, BCS, Mexico","authors":"Gómez-Ávila Marianggy ,&nbsp;Gómez-Arias Efraín ,&nbsp;Rodríguez-González Claudia Alejandra ,&nbsp;Hernández-Paz Juan Francisco ,&nbsp;Lira-Martínez Manuel Alejandro","doi":"10.1016/j.jsames.2025.105404","DOIUrl":"10.1016/j.jsames.2025.105404","url":null,"abstract":"<div><div>In this study, the thermal properties of volcanic igneous rock cores were experimentally measured, considering them ceramic materials (that allows heat transfer conduction efficiently). Five shallow wells (with depths between 42 and 55 m) were drilled, from which different samples of volcanic core rocks (including pumice, tuff, rhyolites, basalts, and basaltic andesite) were recovered. To measure the thermal properties of these materials, the cores were cut using a diamond-tipped rock cutter and dried in an oven between 105 and 120 °C for approximately 12 h to remove excess lubrication fluids. The thermal properties of the rocks (thermal conductivity, thermal diffusivity, and volumetric heat capacity) were measured in twenty-one rock core samples (from five shallow wells) by a Hot Disk Thermal Constants Analyzer. The sample thermal conductivities experimental results were corrected as a function of the log-temperature depths, showing a variation based on the depth at which they were obtained. For example, the thermal conductivity for tuff is 0.73 W/mK at 5.81 m and 1.40 W/mK at 10.20 m for the Refugio well; for pumice is 0.62 W/mK at 3.14 m and 0.52 W/mK at 11.40 m in La Reforma 1 well, and 0.52 W/mK at 3.53 m and 0.56 W/mK at 5.86 m in la Reforma 2 well; for basalt is 0.98 W/mK at 43.53 m and 1.09 W/mK at 43.98 m in La Reforma 1 well, and 1.11 W/mK at 43.30 m in La Reforma 2 well; thermal conductivity of rhyolite is 1.42 W/mK at 55.05 m in La Reforma 2 well; and for the basaltic-andesite rocks, 1.32 W/mK at 43.46 m in El Azufre well, 1.09 W/mK at 6.29 m in La Fumarola well, and 1.674 W/mK at 27.88 m in Refugio Well.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105404"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349592","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":"Concealed morphological diversity revealed by new fossils of Chelus (Testudines, Chelidae) from the Upper Miocene of the Acre Basin, Brazil","authors":"Donato J. Martucci Neto ,&nbsp;Annie Schmaltz Hsiou ,&nbsp;Edson Guilherme ,&nbsp;Leonardo A.T. Costa ,&nbsp;Gabriel S. Ferreira","doi":"10.1016/j.jsames.2025.105408","DOIUrl":"10.1016/j.jsames.2025.105408","url":null,"abstract":"<div><div>The Solimões Formation, in the Acre Basin, which outcrops between the states of Acre and Amazonas, northern Brazil, contains the country's most diverse fossil fauna of Neogene amniotes. The outcrops are mainly found on the erosive margins of the Purus, Acre, and Juruá rivers, among others, since the 19th century. So far, as recorded in other Neogene deposits in northern South America, most of the fossil turtles of the Brazilian Amazon are represented mainly by the clades Chelidae, Podocnemididae, and Testudinidae. The genus <em>Chelus</em> (Chelidae) — popularly known as mata-mata —, represented by two extant species, <em>Chelus fimbriata</em> and <em>Chelus orinocensis</em>, traditionally also includes two extinct species: <em>Chelus colombiana</em> and <em>Chelus lewisi</em>. In Brazil, fossils attributed to the genus <em>Chelus</em> have been reported since the late 19th century. Still, the first valid identifications were made in the 1980s and 1990s, and later in the 2000s, with the proposed presence of <em>C. colombiana</em> and <em>C. lewisi</em> observed in Miocene strata of the Brazilian Amazon. Here, we describe recently discovered fossils housed at the Laboratório de Pesquisas Paleontológicas at the Universidade Federal do Acre (Campus Rio Branco) and assign them to <em>Chelus.</em> Our comparative analyses show that features traditionally and recently used to diagnose the two extinct taxa are present in the same individual. This overlap leads us to question the consistency of these characteristics and consequently the validity of <em>C. lewisi</em>.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"155 ","pages":"Article 105408"},"PeriodicalIF":1.7,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Infiernillo fault, Malargüe fold and thrust belt (Andes of Mendoza), is a Miocene reverse fault: Implications for the tectonic history of the region","authors":"José Francisco Mescua ,&nbsp;Matías Barrionuevo ,&nbsp;Laura Giambiagi ,&nbsp;Julieta Suriano ,&nbsp;Macarena Bertoa del Llano ,&nbsp;Diego Cattaneo ,&nbsp;Matías Olate ,&nbsp;Maximiliano Ruiz","doi":"10.1016/j.jsames.2025.105399","DOIUrl":"10.1016/j.jsames.2025.105399","url":null,"abstract":"<div><div>The Infiernillo fault is located in the Andes of southern Mendoza province, Argentina, within the Malargüe fold and thrust belt. It has been interpreted as a normal fault active in the Miocene and the Quaternary, and is a key element in a model proposing a Quaternary extensional orogenic collapse in the region. However, recent studies have documented a contractional Quaternary deformation regime in this sector, as shown by neotectonic thrusts. Furthermore, the Miocene is the period of the main event of Andean contraction and uplift in the region. Therefore, the interpretation of the Infiernillo fault as a normal structure conflicts with the regional tectonic evolution of the Andes at these latitudes. Based on field observations and fault kinematic data, we conclude that the Infiernillo fault was a reverse out-of-sequence fault in the late Miocene, and did not have a Quaternary reactivation. This implies that the Malargüe fold and thrust belt did not undergo a collapse in the Quaternary. Our results support a model where contractional deformation can be accomodated simultaneously by several structures in different locations across the orogen during the evolution of fold and thrust belts.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105399"},"PeriodicalIF":1.7,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387117","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":"Estimating long-term leaching of As, Pb, and Zn in old mine wastes from center of Mexico","authors":"María Elena García-Arreola ,&nbsp;Luisa María Flores-Vélez ,&nbsp;Marcos Loredo-Tovías ,&nbsp;Alfredo Aguillón-Robles ,&nbsp;Rubén Alfonso López-Doncel","doi":"10.1016/j.jsames.2025.105392","DOIUrl":"10.1016/j.jsames.2025.105392","url":null,"abstract":"<div><div>The mining industry in Mexico has generated a large amount of waste containing potentially toxic elements that have been dumped directly on the ground for many years. Therefore, additional studies are needed to evaluate the environmental impact of these metals. This work performed dynamic leaching tests of potentially toxic elements from historical mining wastes from Monte de San Nicolás and Mineral de Peregrina in the Mining District of Guanajuato, Mexico. The EN 14405:2017 Standard was used L/S ratios at 0.1, 0.2, 0.5, 1, 2, 5, 10, and extended at L/S ratios, 13, 16 and 20. The studied elements were As, Pb, and Zn; the calculated mobility, or release, was determined using the equation proposed by the Dutch Building Materials Decree at liquid-to-solid ratios of 10 and 20. The pH of the tailings and the high percentages of carbonates indicate a low possibility of generating acid drainage. The As, Pb, and Zn cumulative release were greater at the Peregrina site with values of 0.904, 0.016, and 0.210 mg/kg respectively. The 100-year arsenic release estimate at the Peregrina site was 2186 mg/m² at a liquid/solid ratio of 10 and 3408 mg/m² at a liquid/solid ratio of 20, thus exceeding the Dutch decree limit in 15 and 10 years respectively.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105392"},"PeriodicalIF":1.7,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378896","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":"Neoproterozoic magmatic arcs of the Araçuaí-Ribeira Orogenic system (AROS), Brazil","authors":"Monica Heilbron ,&nbsp;Valdecir Janasi ,&nbsp;Cristina Santos Araújo ,&nbsp;Caroline Peixoto ,&nbsp;Bárbara Bueno Toledo ,&nbsp;Raíssa Santiago ,&nbsp;Sandro Mauri ,&nbsp;Adriana Alves ,&nbsp;Fabrício Caxito ,&nbsp;Miguel Tupinambá ,&nbsp;Joventine Decol ,&nbsp;Marcela Lobato ,&nbsp;Felipe Corrales ,&nbsp;Henrique Bruno ,&nbsp;Antônio Carlos Pedrosa Soares","doi":"10.1016/j.jsames.2025.105400","DOIUrl":"10.1016/j.jsames.2025.105400","url":null,"abstract":"<div><div>The last three decades of research within the Araçuaí-Ribeira Orogen (AROS) has provided new field, geochronology, isotopic and geochemical data that reveal a protracted and diachronous tectonic evolution. The two magmatic arc systems IMAS (Inner Magmatic Arc System) and OMAS (Outer Magmatic Arc System) were detected along the AROS, with some important differences along strike are attributed the previous paleogeography characterized by a V-shape Ocean, with two branches that progressively enlarge southwards. The IMAS is the internal continental magmatic arc developed on a continental block of predominantly Rhyacian age, but displaying Archean inheritance. It is a very long ca. 2000 km tectonic block with possibly differences in basement constitution that could have played a role in the heterogeneity of the arc related magmatism. In the Ribeira Orogen, U-Pb ages constrain the ca. 670-620 Ma of the maximum peak of arc magmatism, although a few Cryogenian ages that appear in parts of the IMAS may suggest that convergence could have started before. However, in the Araçuaí/Northern Ribeira Orogen, closure of the precursor basin gulf occurred much later, with 635-585 Ma tonalites and granodiorites of the Rio Doce magmatic arc, with main U-Pb peak of ages around 590 Ma and syn-collisional metamorphic peak at 580-565 Ma. Metamorphic ages constrain the collision of IMAS against São Francisco craton reworked margin between ca. 620-595 Ma. The contrasting OMAS system is detected in the central part of AROS, between the IMAS and the African derived blocks, <em>i.e.</em>, in the Cabo Frio terrane and Luis Alves craton. The OMAS testify to a long period of convergence that resulted on two magmatic stages and related basins: ca. 860-760 Ma and 670-620 Ma. The geochemical and isotopic data of these two stages indicate a progressive continentalization of the arc, that have evolved from a very primitive intra-oceanic setting (advancing stage) to a more evolved setting with increase in the contamination by subducted metasedimentary rocks and the cannibalization of the deep parts of arc itself. Finally, some important open questions for future investigations are discussed.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"155 ","pages":"Article 105400"},"PeriodicalIF":1.7,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395423","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":"Revisiting the upper Triassic Portezuelo Bayo Formation: Sedimentological and paleontological perspectives from Mendoza, Argentina","authors":"Tomas Ezequiel Pedernera ,&nbsp;Adriana Cecilia Mancuso ,&nbsp;Eduardo Guillermo Ottone ,&nbsp;Vanesa Dafne Litvak","doi":"10.1016/j.jsames.2025.105401","DOIUrl":"10.1016/j.jsames.2025.105401","url":null,"abstract":"<div><div>This study focuses on the Portezuelo Bayo Formation (Upper Triassic, Cuyana Basin) through a multidisciplinary approach that includes: petrographic analysis of volcanic and pyroclastic rocks at its base, sedimentological characterization of facies associations and depositional subenvironments, preliminary paleoclimatic reconstruction based on clay mineral assemblages, and documentation of new macrofossil plant remains and palynomorphs. Volcanic deposits from the underlying Agua de la Zorra Formation indicate both explosive and effusive volcanic activity, including pyroclastic flows, ash fall deposits, and basaltic lava flows, which likely contributed to the filling of the Agua de la Zorra paleolake. The Portezuelo Bayo Formation is interpreted as a fluvial system with well-developed floodplains and single-to multi-story channel deposits. Clay mineral analysis suggests that deposition occurred under seasonal climatic conditions, alternating between warm, humid phases and more arid seasons. The paleobotanical assemblage includes <em>in situ</em> logs, impressions, and compressions of leaves, fronds, and stems, along with opaque phytoclasts and sparse palynomorphs dominated by fern spores and conifer pollen. This vegetation is indicative of a forest ecosystem dominated by Umkomasiales and conifers, with an understory of ferns and monotypic horsetail (Equisetales) communities in associated areas. This integrated study provides valuable insights into the depositional, climatic, and ecological conditions of the Portezuelo Bayo Formation, contributing to a more comprehensive understanding of Triassic paleoenvironmental dynamics within the Cuyana Basin.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105401"},"PeriodicalIF":1.7,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143217812","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":"Misconceptions about Lu-Hf isotopic system: A comment on Gómez-Torres et al. (2025) “U-Pb, Hf isotopes and trace elements of zircon reveals a Mesoproterozoic crustal source for the Jurassic Caopas sub-volcanic intrusion: Northern part of the Nazas Igneous Province in Mexico”","authors":"Reneé González-Guzmán","doi":"10.1016/j.jsames.2025.105397","DOIUrl":"10.1016/j.jsames.2025.105397","url":null,"abstract":"<div><div>Gómez-Torres et al. (2025) [DOI: 10.1016/j.jsames.2024.105266] present geochemical data on major and trace elements in rocks and zircons, U-Pb zircon ages, and Lu-Hf zircon isotopic data from a limited sample set to investigate the petrogenesis of Middle Jurassic rhyolite in the subvolcanic Caopas intrusion. Their striking conclusion is that Mesoproterozoic crust (Oaxaquia-like rocks) served as the magma source for this intrusion through crustal reworking in a rift environment. However, I argue that there is no solid evidence to support this assumption. In this commentary, first, several formal issues, errors, and major omissions in the methodological procedures are pointed out, including a key point such as the handling of the zircon Hf model ages (TDM2_[Hf]). Then, a correct treatment of the Lu-Hf data and a more plausible interpretation of the TDM2_[Hf] are provided. This interpretation suggests that a mixing process was involved in the genesis of the Caopas intrusion between an undifferentiated basement (Oaxaquia-like, Permian, or Triassic crustal rocks) and juvenile material (fresh magma).</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"154 ","pages":"Article 105397"},"PeriodicalIF":1.7,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378897","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":"Quaternary coastal evolution of the southern edge of the atacama desert: Modeling uplift and wave erosion of pan de azúcar marine terraces (26°S, 70.6°W)","authors":"Camila Arróspide ,&nbsp;Germán Aguilar ,&nbsp;Joseph Martinod ,&nbsp;María Pía Rodríguez","doi":"10.1016/j.jsames.2024.105308","DOIUrl":"10.1016/j.jsames.2024.105308","url":null,"abstract":"<div><div>The Pan de Azúcar National Park (∼26°S, 70.6°W), located on the southern edge of the Atacama Desert, exhibits for almost 30 km an alongshore morphological segmentation. In this work, we characterized the two contrasting morphological arrangements observed in this area: (1) a wide marine terrace landward backed by a tall coastal cliff, and (2) a sequence of poorly preserved, relatively narrow marine terraces landward backed by a short coastal cliff. Three domains that feature these arrangements are identified. The Central Domain represents the first arrangement, and the Northern and Southern domains represent the second. To understand their formation, we used a simple numerical model that allowed us to better understand the long-term evolution of coastal landscapes in rocky areas. The model gives us first-order insights into the driving processes of the development of coastal morphologies: tectonic history, eustatic sea-level change, and marine erosion. Model results reveal that an initial event of slow subsidence (0.04 mm/yr) between 1 Myr and 400 kyr is likely a necessary condition to develop all contrasting domains. Also, variable uplift rates (0.25–0.35 mm/yr) during the last 400 years have allowed the emersion of dated terraces. With this tectonic history, model results suggest values of marine erosion higher than 1 m²/yr to develop a morphological arrangement such as the Central Domain. Conversely, much lower erosion rates, for instance, 0.25–0.5 m²/yr or less, are necessary to replicate the morphology observed in the Northern and Southern domains. Hence, improving numerical models is a key task in unraveling the modes and temporal and spatial variability of driving and modulating processes.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105308"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181773","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":"Five decades of collaboration with Victor Ramos","authors":"Umberto G. Cordani","doi":"10.1016/j.jsames.2024.105311","DOIUrl":"10.1016/j.jsames.2024.105311","url":null,"abstract":"","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105311"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181776","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}