Journal of South American Earth Sciences最新文献

{"title":"Hydrological regime shifts driven by climate and anthropogenic interference in the Upper Paraná River Basin, Brazil","authors":"Hua Yan","doi":"10.1016/j.jsames.2025.105834","DOIUrl":"10.1016/j.jsames.2025.105834","url":null,"abstract":"<div><div>Climate change coupled with land-use dynamics drives hydrological alterations, posing risks to water quality and sustainable water resource management. Understanding hydrological responses is key to analyzing the interplay between hydrometeorological processes, yet capturing spatiotemporal variability within basins remains challenging without an integrated assessment addressing interconnected dynamics and change points from climatic and human influences. This study developed a framework combining hydrology model, mutation test, and hydrological sensitivity analysis to evaluate this interplay in Upper Paraná River Basin, Brazil, from 1980 to 2020. The results indicated a general downward trend in the monthly average annual runoff and precipitation in the last decade. The hydrological mutation analysis identified obvious shifts in around 1999 and 2008. The results show a significant temporal shift in the drivers of runoff. Climate change dominated between 1980 and 1998, explaining approximately two-thirds of the total variation. The impact of climate change decreased by 23 % between 1999 and 2007 due to increased human activities such as reservoir construction and land-use change. From 2008 to 2020, continued precipitation reductions and anthropogenic interference led to a more complex hydrological response. Implementing targeted measures, such as regulating reservoir operations and optimizing irrigation system, offers viable pathways for ensuring the sustainable management and utilization of water resources.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105834"},"PeriodicalIF":1.5,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326178","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":"Reconstruction of permafrost cover and periglacial dynamics during the last permafrost maximum at Cofre de Perote volcano, Mexico","authors":"Jorge Angel Arano-Robledo ,&nbsp;Víctor Soto","doi":"10.1016/j.jsames.2025.105833","DOIUrl":"10.1016/j.jsames.2025.105833","url":null,"abstract":"<div><div>Synchronous with the Last Glacial Maximum (LGM), a Last Permafrost Maximum (LPM) also occurred, during which maximum global permafrost coverage was reached. Despite its strategic location and the existence of glacial evidence at Cofre de Perote, no local studies have addressed this topic. Using records of ground and air temperature, and by arithmetically adjusting present-day temperature values with the estimated cooling that occurred during the LPM, we reconstructed permafrost coverage and periglacial dynamics for this period. Between 1960 and 2020, the average temperature in the Trans-Mexican Volcanic Belt increased by 0.43 °C. Furthermore, the presence of permafrost during the LPM was confirmed: its lower limit was located at 3870 m a.s.l., covering an area of 7 km², while seasonal frozen ground extended down to 3553 m a.s.l. The active layer persisted from April to June, with an average thickness of 55 cm near the summit. The ground profile exhibited a geothermal gradient of 0.0197 °C/cm, while the vertical air temperature gradient was −0.0057 °C/m. Freeze-thaw cycles followed a parabolic trend, with a total of 148 cycles near the summit, increasing to 244 cycles at 4137 m a.s.l., and decreasing again to 84 cycles at 3870 m a.s.l. These results suggest that the periglacial conditions and landscape at this mountain during the LPM were similar to the present-day conditions at Pico de Orizaba volcano. This study contributes to the paleoclimatic reconstruction of this mountain and provides a reference framework for future scenarios in the cryosphere of intertropical regions.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105833"},"PeriodicalIF":1.5,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326186","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":"Postglacial eruptive history of Laguna del Maule volcanic field and constraints on its magmatic system","authors":"Judy Fierstein ,&nbsp;Patrica Sruoga ,&nbsp;Alvaro Amigo ,&nbsp;Manuela Elissondo ,&nbsp;Mario Rosas","doi":"10.1016/j.jsames.2025.105813","DOIUrl":"10.1016/j.jsames.2025.105813","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Laguna del Maule (LdM) volcanic field has produced &gt;100 explosive and extrusive events over the past 17 ka. More than two-thirds of these have been silicic, with most being postglacial rhyolites (72–78 % SiO&lt;sub&gt;2&lt;/sub&gt;) concentrated near the eponymous lake (LdM), an extraordinary anomaly in the Quaternary Andes and unprecedented in this 1.5–Ma-old volcanic field as a whole. The postglacial field includes &gt;70 separate vents distributed over ∼360 km&lt;sup&gt;2&lt;/sup&gt; that together produced the many distinct eruptive events, of which 55 are rhyolitic (73 %−77 % SiO&lt;sub&gt;2&lt;/sub&gt;), 18 are rhyodacitic (68 %−72 % SiO&lt;sub&gt;2&lt;/sub&gt;), 4 are dacitic (63 %–66 % SiO&lt;sub&gt;2&lt;/sub&gt;), 26 are intermediate (54–62 % SiO&lt;sub&gt;2&lt;/sub&gt;), and 2 are true basalts (50 %–53 % SiO&lt;sub&gt;2&lt;/sub&gt;). Of these, most originated from single-vent domes, cones, or craters that erupted effusive and/or explosive products, each with relatively short lifespans. Some originated from multi-vent centers, the largest one being the Barrancas complex southeast of the lake, which has as many as 18 vents that erupted over as much as 10 kyr. The LdM basin itself is ringed by 13 separate silicic centers, many of which are also multi-vent and built over time by multiple explosive and extrusive events. These surround the lake, near the middle of which is the vent for the high-silica rhyolite Plinian eruption that produced the “&lt;em&gt;Rhyolite of Laguna del Maule&lt;/em&gt;”, which was the first and largest silicic event from the postglacial field. Explosive and effusive products from all these events have been put in a time-stratigraphic framework supported by radiocarbon dating and chemical analyses to reconstruct the postglacial eruptive history. Correlations of pyroclastics to eruptive vents have provided a spatial-temporal framework that helps characterize the magmatic system beneath the LdM field. Distribution of both silicic and mafic vents support the likelihood that two separate magmatic systems produced the postglacial eruptions in the volcanic field—one in the Laguna del Maule basin and the other at the Barrancas complex—with a cluster of silicic vents at each and mafic vents situated between the two. Vent distributions, compositions of eruptive products, and temporal and spatial trends of eruptive units suggest that the abundant rhyodacitic and mafic units in the LdM basin have no common magma reservoir, but instead each had its own evolutionary trend. In contrast, there is enough affinity among some of the rhyolitic units in the Basin to imply magmatic connections and/or continuity that span both time and space, although neither geographic proximity nor temporal similarity have singular control on LdM-basin rhyolite compositions. Compositional trends through time at the Barrancas center suggest the rhyolitic eruptions at West and East Barrancas were derived from separate, zoned reservoirs that were tapped in batches, not permitting development of a large high-silica reservoir such as tha","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105813"},"PeriodicalIF":1.5,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145364651","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":"Pennsylvanian foraminifera from the Río Nevado Formation, Chibcha Terrane, Colombia: biostratigraphic and paleobiogeographic approach","authors":"Luiza Dias Ferreira Lamouche ,&nbsp;Andrés Felipe Rojas Mantilla ,&nbsp;Luciane Profs Moutinho ,&nbsp;Ana Karina Scomazzon","doi":"10.1016/j.jsames.2025.105827","DOIUrl":"10.1016/j.jsames.2025.105827","url":null,"abstract":"<div><div>This study presents the first taxonomic description, biostratigraphic analysis, and paleobiogeographic interpretation of Pennsylvanian Fusulinidae, specifically the genera <em>Fusulinella</em> and <em>Beedeina</em>, from the Río Nevado Formation in the Chibcha Terrane, Colombia. The investigated section comprises shallow marine deposits, where part of the Paleozoic sequence is exposed and tectonically deformed by the Andean Orogeny. This outcrop has previously been dated from the Pennsylvanian to the Lower Permian based on invertebrate fossil assemblages such as brachiopods, trilobites, and ammonoids, which provide lower biostratigraphic resolution compared to foraminifera. As part of an accreted terrane, determining the original paleogeographic position of this crustal block has posed significant challenges. The fusulinid assemblage described herein provides a refined biostratigraphic framework, allowing for high-resolution correlation with the Moscovian Stage. The data also align with recent conodont studies from the same samples, supporting both biostratigraphic and paleobiogeographic correlations with fusulinid and conodont faunas from the North American Midcontinent region. These results reinforce the hypothesis that the Chibcha Terrane may have originated from a region within North America prior to its accretion to northwestern South America.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105827"},"PeriodicalIF":1.5,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326002","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":"Gastropod predation and parasitism on echinoids from Jandaíra Formation (Turonian-Maastrichtian), Potiguar Basin, Northeast Brazil","authors":"J.H.B. Xavier ,&nbsp;W.B.S. Almeida ,&nbsp;C.L.C. Manso ,&nbsp;A.M. Ghilardi ,&nbsp;C.L.A. Santos ,&nbsp;D. Sedorko ,&nbsp;S.M. Scheffler","doi":"10.1016/j.jsames.2025.105830","DOIUrl":"10.1016/j.jsames.2025.105830","url":null,"abstract":"<div><div>Fossil echinoids bearing boreholes offer valuable information about the paleoecology of both the echinoids and their tracemakers, assisting paleobiological interpretations. Gastropods are the main bioeroders of echinoids, and their boring strategies vary among families. Cassidae and Eulimidae are regarded as the classical bioeroders of echinoids, whereas Naticidae and Muricidae follow alternative strategies that may also produce drill holes on echinoid tests. In this study, we searched for boreholes in seven hundred and forty-six (746) echinoid specimens of 3 different orders (Spatangoida, Cassiduloida, and Phymosomatoida), from the Jandaíra Formation (Upper Cretaceous, Potiguar Basin). Forty-five (45) echinoid specimens exhibit drill holes assigned to the ichnogenus <em>Oichnus</em> Bromley, 1981<em>,</em> attributed to gastropod activity. These bioerosion structures are interpreted as predation and parasitism. Size and site can help distinguish between the two interpretations, but those around 1 mm can be dubious. To avoid misclassification, K-means clustering was used to differentiate between two clusters (the larger representing predation and the smaller mostly representing parasitism). The tracemaker of the potential parasitic boring is probably an Eulimidae gastropod, a group not yet described for the Jandaíra Formation. In regard to drilling intensity between the orders, Spatangoida presented the highest frequency (∼8 %), however, the Fisher's Exact Test indicated that the difference to Cassiduloida (∼7 %) was not significant (<em>p</em> &gt; 0.75). In contrast, the difference between either one and Phymosomatoida was significant (<em>p</em> &lt; 0.01). Perhaps the difference in the frequency of drilled echinoids is related to differences in the preservational potential influenced by borehole presence. This study contributes to the understanding of trophic interactions in the Cretaceous marine ecosystems and expands the ichnological record of the Jandaíra Formation.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105830"},"PeriodicalIF":1.5,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326187","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 legacy data from the oil industry to evaluate volcanic formations for geological CO2 storage: A case study from the Campos Basin, Brazil","authors":"Germano Mario Silva Ramos ,&nbsp;José Antonio Barbosa ,&nbsp;Osvaldo José Correia Filho ,&nbsp;Carla Joana Barreto ,&nbsp;Jefferson Tavares Cruz Oliveira ,&nbsp;Tiago Siqueira de Miranda ,&nbsp;Aline Macrina da Silva ,&nbsp;Roberta Samico de Medeiros ,&nbsp;Tallys Celso Mineiro","doi":"10.1016/j.jsames.2025.105808","DOIUrl":"10.1016/j.jsames.2025.105808","url":null,"abstract":"<div><div>Geological CO₂ Storage (GCS) in basaltic/volcanic formations is a promising avenue for mitigating anthropogenic emissions of greenhouse gases because these regions can effectively trap CO₂ via mineralization. However, implementing CO₂ storage projects in offshore regions demands significant investment due to the requirement to explore vast areas as well as characterize any potential prospects to verify their technical and economic feasibility. Legacy data from the oil industry could be used to provide an initial assessment of potential prospects in sedimentary basins with volcanic formations. In this study, we demonstrate the immense value of legacy products, including seismic and well log data, to identify zones with higher potential for CO₂ storage. This study investigates the unconventional, mature volcanic oil reservoir of the Cabiúnas Formation in the Badejo Field, Campos Basin, Brazil, because the flood basalts that formed these reservoirs represent candidates for GCS projects in shallow water domains. Understanding the mechanism of hydrocarbon migration and accumulation in these reservoirs will provide insights into the factors that control fluid flow in basaltic rocks, helping eventual future investigation focusing CO₂ storage. This investigation employed tools commonly used by the industry for exploratory investigations and reservoir characterization, based on seismic data interpretation and attribute analysis. We also performed porosity distribution estimation with an acoustic impedance inversion method based on a neural network plugin. The legacy data allowed us to characterize the complex relationships between fractures and aspects such as paleo-topography and the control of fault zones on lateral flow. We find that the relationship between faults/fractures and the apparent porosity of the volcanic succession is critical for predicting the reservoir response to CO₂ injection. Legacy data from the oil industry that covers offshore regions that contain volcanic successions thus represents a valuable resource that can help save costs and accelerate the development of GCS projects.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105808"},"PeriodicalIF":1.5,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326176","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 first record of a thunnosaurian ichthyosaur from the upper Albian of South America","authors":"Daniel Eduardo Pomar,&nbsp;Cristian David Benavides-Cabra,&nbsp;José Alejandro Narváez-Rincón","doi":"10.1016/j.jsames.2025.105824","DOIUrl":"10.1016/j.jsames.2025.105824","url":null,"abstract":"<div><div>This study describes the first thunnosaurian ichthyosaur specimen discovered in the upper Albian beds of the Hilo Formation at Guayabal de Síquima (Cundinamarca, Colombia), representing the first record of an ichthyosaur from the Albian of Colombia and South America. The specimen comprises a segment of the axial skeleton, including 31 articulated and 2 disarticulated vertebral centra, several ribs, gastralia fragments, and disarticulated appendicular elements. We assign the specimen to Thunnosauria based on the presence of ribs with 8-shaped cross-section. Nearly all Cretaceous thunnosaurians are ophthalmosaurids, with the exception of <em>Malawania anachronus</em>. The specimen is comparable in size to some ophthalmosaurids and is larger than <em>M. anachronus</em>. However, no diagnostic features support its inclusion within Ophthalmosauridae. Therefore, despite its Albian age and size consistency with Ophthalmosauridae, we conservatively limit the systematic position of the new specimen to Thunnosauria. The abundance of organic matter, pyrite and high articulation of the specimen, suggest deposition in anoxic waters with high organic matter content, which limited benthic fauna and prevented disarticulation by scavengers. This interpretation aligns with previous analyses of the Hilo Formation's depositional environment.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105824"},"PeriodicalIF":1.5,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270229","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 convergence model for the SW Gondwana margin during the late Paleozoic based on the structural analysis of accretionary complexes in northern and south-central Chile","authors":"Juan Díaz-Alvarado ,&nbsp;Carlos Fernández ,&nbsp;Andrés Folguera ,&nbsp;Christian Creixell ,&nbsp;Verónica Oliveros ,&nbsp;Juan Carlos Moral","doi":"10.1016/j.jsames.2025.105826","DOIUrl":"10.1016/j.jsames.2025.105826","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study presents a comprehensive analysis of the convergence style in the accretionary complexes along the Chilean coast, focusing on the structural study of the Maule River section (35° S), to shed light on the complexity of the subductive southwestern Gondwana margin during the late Paleozoic. The Maule River section, part of the Coastal Accretionary Complex of Central Chile, provides insights into the structural configuration of the basal and frontal accretionary wedge, and is compared in this work with the Chañaral mélange, more than 1000 km to the north. The structural analysis reveals significant differences in the convergence parameters (subduction zone boundary azimuth, convergence direction, flow trajectories). The aim of this study is to assess the influence of convergence style on the differences in lithological, metamorphic, and structural characteristics between these two widely separated fragments of the Carboniferous accretionary complex.&lt;/div&gt;&lt;div&gt;The Maule River section is characterized by two well-differentiated sectors: the Eastern Series, comprising low-grade phyllites and quartzites, and the Western Series, consisting of albite-bearing pelitic schists, greenschists and amphibolites, recording medium-high pressure conditions and temperatures below 500 °C. To the east, the Carboniferous magmatic arc and its basement are tectonically juxtaposed to the metasedimentary wedge.&lt;/div&gt;&lt;div&gt;The Eastern Series exhibits structures with opposed vergences: eastward in the eastern area and west-northwestward in the central and western areas. In contrast, the Western Series shows different structural patterns, including isoclinal folds and abundant S-C structures. The main schistosity presents E-W to N-S directions dipping moderately to the south and east respectively. The mineral and stretching lineation trends mostly E-W to NW-SE with low plunges towards the east and southeast, indicating top-to-the-WNW displacement.&lt;/div&gt;&lt;div&gt;A 3D kinematic model applied to the structural data collected in the Maule river section results in a triclinic to monoclinic transpressive shear zone (subduction channel and its influence zone), with a constrictional coaxial component (&lt;em&gt;K&lt;/em&gt; = 5) and with the simple shear direction acting parallel to the dip of the subduction zone boundary. The particle flow trajectories (extrusion direction) fluctuated ±60° around the convergence direction of N123E ±24°, orthogonal to the margin azimuth. In the Chañaral area, both the convergence direction (N50-60E) and the extrusion trajectories predicted for the materials in the shear zone, with a low pitch on the boundary of the deformation zone, contrast with the results obtained in the Coastal Accretionary Complex of Central Chile. The differences in the late Paleozoic margin configuration may partially explain the absence of high-pressure rocks in the north (Chañaral area), although other post-accretionary processes such as tectonic erosion and block rotatio","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105826"},"PeriodicalIF":1.5,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270227","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":"Pre-Andean and Andean shortening in the Eastern Cordillera of NW Argentina at 23°S","authors":"Juan Luis Alonso ,&nbsp;Luis Quintana ,&nbsp;Jorge Gallastegui","doi":"10.1016/j.jsames.2025.105809","DOIUrl":"10.1016/j.jsames.2025.105809","url":null,"abstract":"<div><div>The Eastern Cordillera, in NW Argentina, is an imbricate thrust system involving Precambrian to Cenozoic stratigraphic units. Structural analysis shows that the Cretaceous unconformity truncates previous thrusts and related folds, but most of the Andean structures result from the reactivation of pre-Andean thrusts and folds. The total shortening for the Eastern Cordillera is about 46 km, of which 30 km are Andean in age and about 16 km correspond to the original Paleozoic imbricate.</div><div>A complete cross-section through the Eastern Cordillera and the Interandean Zone at 23°S is presented and a sequential restoration of Andean and pre-Andean structures was carried out. In this section, two basement sheets, each about 10 km thick, have been inferred below the Eastern Cordillera from displacement transfer analysis. The thrust sequence was established on the basis of quantitative analysis of displacement transfer. The first basement sheet to be emplaced reactivated the floor thrust of the previous Paleozoic imbricate system, and accounts for the cumulative shortening of Andean thrusts in the Eastern Cordillera. The second one developed in forward sequence, transferring more than 60 km to the sole thrust of the Subandean imbricate system. It is the main thrust and gave rise to the uplift and deep exhumation of the primitive Eastern Cordillera, causing a fast increase in subsidence rates in the Subandean foreland basin. Later, a second movement of the first basement sheet transferred about 8 km of displacement towards several out-of-sequence thrusts, giving rise to the intermontane Humahuaca Basin.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105809"},"PeriodicalIF":1.5,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326188","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":"Assessment of landslide susceptibility triggered by precipitation in the Metropolitan Region of Recife, Brazil","authors":"Aline Pessoa Bezerra ,&nbsp;Carlos Antonio Costa dos Santos ,&nbsp;Celso Augusto Guimarães Santos ,&nbsp;Weber Andrade Gonçalves ,&nbsp;Gabriel de Oliveira","doi":"10.1016/j.jsames.2025.105812","DOIUrl":"10.1016/j.jsames.2025.105812","url":null,"abstract":"<div><div>Landslide events can severely impact communities, underscoring the need to understand local dynamics and rainfall-related triggers when assessing susceptibility. This study pursued three main objectives: (1) to identify critical precipitation thresholds for landslide-triggering rainfall in the Recife Metropolitan Region (RMR), Brazil, from 2016 to 2022, using two empirical methods— the event duration (ED), based on accumulated precipitation, and the intensity–duration (ID), based on rainfall intensity over specific periods; (2) to create a comprehensive landslide inventory map; and (3) to develop a regional susceptibility map using machine-learning algorithms (RF, KNN, XGBoost, and NB) to identify key destabilizing factors. A total of 221 landslides were mapped across the region. The ED method showed stronger correlations with local landslide occurrences (R² &gt; 97.5 %) compared to the ID method (R² &lt; 90.5 %). Susceptibility modeling incorporated nine factors, with land use, elevation, and geomorphology emerging as the most influential in slope instability. The resulting susceptibility map was classified into five categories: very low (28 %), low (35 %), moderate (27 %), high (9 %), and very high (1 %). Model performance was validated using ROC analysis, with the RF model achieving excellent predictive capability (AUC = 0.905). These findings offer valuable insights for landslide risk management in the study area, highlighting the importance of accumulated precipitation and terrain characteristics. The susceptibility map offers an evidence-based foundation for proactive measures to mitigate landslide impacts.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"168 ","pages":"Article 105812"},"PeriodicalIF":1.5,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326177","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}