Journal of South American Earth Sciences最新文献

{"title":"Corrigendum to ‘Paleolimnology based on organic matter analysis and geochemical studies: Santa Clara Abajo Formation (Triassic), Cuyana Basin, Mendoza, Argentina’ [J. S. Am. Earth Sci., 165 (2025) 105721]","authors":"Federico Siderac , Georgina Erra , Marcos Comerio , Fernando Larriestra , Cecilia Andrea Benavente","doi":"10.1016/j.jsames.2025.105743","DOIUrl":"10.1016/j.jsames.2025.105743","url":null,"abstract":"","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105743"},"PeriodicalIF":1.5,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048998","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":"Shallow landslides assessment in the wildland-urban interface: The Palomares Basin case study","authors":"Emiliano Vega-Ruiz , Edilia Jaque , Alfonso Fernández , Ianire Galilea , Frank Tinapp","doi":"10.1016/j.jsames.2025.105740","DOIUrl":"10.1016/j.jsames.2025.105740","url":null,"abstract":"<div><div>Shallow landslides are a recurrent and destructive hazard in the Metropolitan Area of Concepción, Chile, having caused at least 17 fatalities since 1980 along with substantial economic losses. The Palomares Basin, located on the urban fringe of Concepción, is characterized by a wildland-urban interface where urban development is surrounded by hills covered with plantations. This area is particularly vulnerable to both wildfire and landslide hazards, which are exacerbated by vegetation loss and increased soil erosion. This scenario highlights a pressing territorial issue: the impact of deforestation and the forestry activities on landslide occurrence within the wildland-urban interface.</div><div>The Palomares Basin exhibits regional conditions that are typical yet often overlooked: (1) deep, well-developed soils derived from highly weathered granitic regoliths, (2) steep slopes, (3) high-intensity rainfall, and (4) socio-economic factors such as: (a) the occupation of marginal hilltop areas due to socio-economic segregation, (b) inadequate land-use planning, and (c) human-induced factors that increase landslide susceptibility, particularly deforestation.</div><div>To assess the impact of deforestation on soil mechanics and root cohesion, and the subsequent increase in shallow landslide probability, we simulated pre- and post-deforestation scenarios using the STEP-TRAMM software. The input data included rainfall events from 2019; soil depth; elevation (using 0.2 m<sup>2</sup> LiDAR pixels for individual slopes and 5 m<sup>2</sup> pixels for the entire basin); soil texture; cohesion; friction angle; landslide inventory (derived from fieldwork and remote sensing); initial soil saturation; root cohesion; and vegetation cover status (pre- and post-deforestation, as detected through multispectral and high-resolution imagery analysis).</div><div>The software quantified the spatio-temporal probability and magnitude of landslides by accounting for changes in soil cohesion resulting from the loss of tree root structures. Simulations were validated against the landslide inventory, with a focus on comparing the effects of deforestation. Results indicated a significant increase in landslide probability under deforested conditions, with the post-deforestation scenario showing up to three times more landslides and five times more displaced material. At both the single-slope and basin scales, up to 70 % of simulated landslides coincided with the landslide inventory. At the single-slope scale, the best fit for spatio-temporal and volumetric landslide generation occurred with initial soil saturation levels between 0.5 and 0.8 and a soil cohesion of 1 kPa, with minimal temporal discrepancies between simulated and actual scenarios. At the basin scale, initial soil saturation levels of 0.5–0.7 and a soil cohesion of 3 kPa were most appropriate. Under similar precipitation events, deforestation was found to substantially increase landslide risk, exacerbating","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105740"},"PeriodicalIF":1.5,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144904236","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":"Middle Ordovician graptolite biostratigraphy from volcaniclastic turbidites and a new U-PB zircon age from the Huaytiquina section, western Puna, Argentina","authors":"Blanca A. Toro ,&nbsp;Pamela A. Aparicio González ,&nbsp;Nexxys C. Herrera Sánchez","doi":"10.1016/j.jsames.2025.105737","DOIUrl":"10.1016/j.jsames.2025.105737","url":null,"abstract":"<div><div>Graptolites studies constitute the main scientific contribution to the understanding, dating, and correlation of early Paleozoic sedimentary sequences in the Argentine Puna. They also recently provided pioneering insights for a high-resolution stratigraphy in the region, based on the comparison with the conodont results. This study analyzes, for the first time, the ages independently obtained from the graptolite biostratigraphic framework of the western Puna, at the Huaytiquina section, and the U-Pb zircon age of a tuff layer found at the top of this section, corresponding to the Puna Turbidite Complex. Graptolite records from the Huaytiquina section allowed the assignment of the lower part of the Puna Turbidite Complex to the <em>Azygograptus lapworthi</em> Biozone (early Dapingian, Dp1). In the middle part of the sequence, specimens of <em>Isograptus</em> sp. and <em>Tetragraptus bigsbyi</em>, associated with the conodont <em>Baltoniodus</em> cf. <em>B. navis</em>, suggest a middle Dapingian age (Dp2) for the carbonate-bearing levels. Furthermore, the presence of <em>Isograptus divergens</em> in the Catua section, located a few kilometers southeast of Huaytiquina, supports the hypothesis that deposits corresponding to the late Dapingian (Dp3) to early Darriwilian (Dw1) may also be present in the upper part of the Huaytiquina section. The U-Pb ages maximum likelihood age of deposition (MLA) or maximum depositional age (MDA) obtained from a tuff layer identified at the top of the Huaytiquina section is 479 ± 8 Ma, with youngest zircons of darriwilian ages (461 ± 22 Ma). In addition, the recycling zircons populations are Cambro-Ordovician ages, with a smaller proportion of Neoproterozoic and Paleoproterozoic zircons. As a result, the biostratigraphic information based on recent graptolite records helps to bridge the gap between the ages of the bearer levels and the age suggested by the analyzed zircons at the Huaytiquina section.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105737"},"PeriodicalIF":1.5,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144866562","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 Maastrichtian-Danian Yacoraite Formation, Salta Group, Eastern Cordillera, Argentina: influence of paleorelief on the sedimentological composition","authors":"Pamela Alejandra Aparicio González ,&nbsp;Lubín Eric Cayo ,&nbsp;Natalia Hauser ,&nbsp;Arnold Garcia Zavaleta ,&nbsp;Ignacio Gallardo ,&nbsp;Margarita Do Campo ,&nbsp;Wolf Uwe Reimold","doi":"10.1016/j.jsames.2025.105720","DOIUrl":"10.1016/j.jsames.2025.105720","url":null,"abstract":"<div><div>The influence of paleorelief as an indicator of the source area is analyzed here for the Yacoraite Formation of the Balbuena Subgroup (Salta Group). Provenance analysis based on detrital zircon was performed on four samples from the Yacoraite Formation in the Maimará and Juella sections. This analysis was combined with Multidimensional Scaling (MDS) techniques and U-Pb chronology previously obtained for all units underlying the Yacoraite Formation in the Tres Cruces subbasin.</div><div>For the Yacoraite samples from the Maimará section, the main sources of detrital zircons correspond to the basement units (Mesón Group and Puncoviscana Complex). At the top of the Yacoraite Formation, Ordovician zircons from the Santa Victoria Group were identified. In the Juella section, a sample from the undifferentiated Pirgua Subgroup contained Triassic and Carboniferous zircons that may be derived from Permian-Triassic plutons in the Puna region of Salta Province. Other zircons from this sample, of Ordovician, Cambrian, and Neoproterozoic age, are related to the basement of the area (Santa Victoria and Mesón groups, and the Puncoviscana Complex).</div><div>MDS analysis indicates that the closest similarity is between the U-Pb age distributions of the Pirgua Subgroup and the Jurassic Tacurú Group. The sample from the base of the Yacoraite Formation in the Juella section contains zircons (90 %) from the basement. Additionally, Devonian zircons may originate from Devonian magmatism in southern Peru.</div><div>MDS suggests similarity between the U-Pb age distributions of samples from the Lower Yacoraite Formation and the underlying units, indicating that the Pirgua Subgroup, the Mesón and Santa Victoria groups, and the Puncoviscana Complex are potential sources for the lower Yacoraite Formation.</div><div>In conclusion, the paleorelief of the hinterland has been a key control on the composition of the Yacoraite Formation. Detrital zircon populations for this formation can be successfully related to locally exposed sources.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105720"},"PeriodicalIF":1.5,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889243","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 on the evolution of the interference zone between the Southern Brasília and the Central Ribeira orogens, SE Brazil: Implications from new U-Pb ages of late- to post-collisional granitoids","authors":"Marcela Perroti Simas,&nbsp;Ivo Antonio Dussin,&nbsp;Rodrigo Peternel Machado Nunes,&nbsp;Mauro Cesar Geraldes","doi":"10.1016/j.jsames.2025.105742","DOIUrl":"10.1016/j.jsames.2025.105742","url":null,"abstract":"<div><div>In southeastern Brazil, the Mantiqueira Province, formed during the Brasiliano-Pan-African Orogenic Cycle, records a complex and diachronous evolution. Contextually, the Southern Brasília (SBO) and Central Ribeira (CRO) orogens developed between the Ediacaran and Cambrian. The boundary between these orogens, and the overprinting of the older SBO by the younger CRO, remains a topic of debate, particularly in the Socorro Nappe, which spans the border region of Rio de Janeiro, Minas Gerais and São Paulo states. To contribute to this debate and to improve understanding of the tectono-magmatic evolution, this study presents field observations, petrographic data and new U-Pb zircon ages (LA-SF-ICP-MS) for four granitoids interpreted as crystallization ages: the Getulândia (608.5 ± 7.1 Ma), Capivara (602.4 ± 12 Ma and 604.1 ± 6.9 Ma) and the porphyritic Serra do Lagarto and Maromba granites (589.8 ± 8.4 Ma and 573.9 ± 4.4 Ma, respectively). Combined with published data, two petrographically and geochronologically similar groups are proposed: an older group (ca. 610-600 Ma), interpreted as late-tectonic, and a younger group (ca. 595-570 Ma), interpreted as post-tectonic relative to the evolution of the SBO. These granitoids, locally affected by shear zones and metamorphism linked to the CRO, define an extensive late- to post-collisional magmatic province from Getulândia (RJ) to Apiaí (SP). It is proposed that they were emplaced during the orogenic collapse of the SBO, later overprinted by CRO events, supporting the interpretation that the study area, which lies within the Socorro Nappe, is tectonically associated with the Paranapanema paleocontinent, and located within the interference zone between the two orogens.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105742"},"PeriodicalIF":1.5,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889242","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":"Relationship between Neogene volcanic centers and the foreland advance of deformation: The Malargüe fold-and-thrust belt 35°-36°S, 69°50′W, Southern Central Andes, Argentina","authors":"Paula A. Arcila Gallego ,&nbsp;Rafael Robertson Luco ,&nbsp;Jhon-Meyer Muñoz","doi":"10.1016/j.jsames.2025.105732","DOIUrl":"10.1016/j.jsames.2025.105732","url":null,"abstract":"<div><div>The presence of Neogene volcanic centers have been poorly studies between 35° and 36°S, 69°50′W in the Malargüe Fold-and-Thrust Belt, Argentina. This work used field observations, stratigraphic sections, whole-rock geochemistry, and ⁴⁰Ar/³⁹Ar geochronology to characterize three polygenetic volcanic successions: Butamallín, Fiero, and Picudo de la Ventana and their relationship with the synorogenic deposits. Their emplacement spans from the Early Miocene (16.7 ± 1.7 Ma), through the Late Miocene (9.8 ± 1.0 Ma), to the Pliocene (6.5 ± 0.5 Ma), with each center displaying distinctive geochemical signatures associated with retroarc magmatism, arc-related magmatism, and retroarc magmatism with depleted mantle affinities. The volcanic successions unconformably overlie synorogenic units, acting as sediment sources and influencing basin architecture. The relationship with synorogenic successions, together with paleoflow indicators and clast compositions, reveals four evolutionary stages: (1) a foreland basin in the Early Miocene, (2) the development of wedge-top basins during the Middle Miocene, (3) arc migration and volcanic expansion in the Late Miocene, and (4) the formation of piggyback basins associated with mantle-derived magmatism from the Late Miocene to the Pliocene. These results support a model of forelandward (eastward) propagation of the Malargüe Fold-and-Thrust Belt (MFTB) in the southern Central Andes of Argentina.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105732"},"PeriodicalIF":1.5,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144889240","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":"Porosity estimates in an Albian carbonate reservoir in southeastern Brazil using basic well logs, core sample measurements, and fuzzy logic approach","authors":"A. Carrasquilla ,&nbsp;H. Rocha","doi":"10.1016/j.jsames.2025.105735","DOIUrl":"10.1016/j.jsames.2025.105735","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study was performed in a carbonate reservoir located in southeastern Brazil, comprising calcarenites from the Quissamã Formation, which are significant regional oil-bearing reserves. Conventional well logs, including natural gamma ray, bulk density, neutron porosity, deep resistivity, and sonic or transit time logs, were utilized as input. Porosity estimates were produced via an artificial intelligence methodology employing fuzzy logic, and the precision of these results was verified against core sample values, considered effective porosity. The selected inference system was the Mamdani technique, which uses fuzzy sets to correlate inputs with outputs. The selected triangular membership functions and the established fuzzy rules that support the models are essential. The results achieved are considered promising; however, it is important to remember that fuzzy logic models, like any estimation method, may be susceptible to uncertainties. The results indicate that utilizing individual logs for porosity inference yields optimal outcomes with the sonic log, exhibiting a Pearson correlation coefficient of 0.75, a minimal absolute error of 2.8, and a Willmott agreement index of 0.24. This log mostly pertains to primary porosity, indicating that the estimation is only valid under these circumstances. The optimal combination for the pairings was the sonic and gamma ray logs yielding values of 0.78, 2.71, and 0.40. This estimate surpasses the prior one, as the sonic log is shown in conjunction with the gamma ray log, despite being linked to reduced porosity, since it quantifies the presence of clay or carbonate mud. The optimal combination of the three logs was sonic, density, and neutron, with values of 0.74, 2.95, and 0.37, respectively. This estimate coincides with the preceding two, as the sonic log is associated with primary porosity, while the density and neutron logs pertain more to total porosity. Using four logs: acoustic, gamma ray, density, and neutron logs produced values of 0.72, 2.94, and 0.42 using four logs. This estimate is comparable to previous ones, while there remains uncertainty on the inclusion of the gamma ray log in the group. The results obtained from utilizing all five logs are 0.51, 3.71, and −0.47, which constitutes an unsatisfactory estimate. This can be explained by the incorporation of the resistivity log, which is more related to the fluids contained within the rock's pores. The results indicate that the most accurate porosity estimate was achieved through the integration of acoustic and gamma ray logs. The acoustic log is present in all estimates, but the resistivity log is included only in the final one. As the Pearson correlation coefficient diminishes, the minimum absolute error increases, while the Willmott agreement index reveals variability. This method of assessing porosity led to the conclusion that all estimates should be considered in an accurate evaluation and that the logs can be applied with ar","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105735"},"PeriodicalIF":1.5,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144829467","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":"Interplay between structural framework and diagenetic processes in the Barra Velha Formation: A study from Tupi Field, Santos Basin, Brazil","authors":"Mariana Meireles Leite ,&nbsp;Tiago Amâncio Novo ,&nbsp;Humberto Reis ,&nbsp;Tobias Fonte Boa ,&nbsp;Fernanda Moura Costa ,&nbsp;Deniro Felipe Gonçalves Costa","doi":"10.1016/j.jsames.2025.105733","DOIUrl":"10.1016/j.jsames.2025.105733","url":null,"abstract":"<div><div>The Cretaceous pre-salt reservoirs of the eastern Brazilian passive margin basins store major oil and gas reserves, representing some of the most significant hydrocarbon discoveries of recent decades. Despite extensive research, critical questions remain about their depositional nature, post-depositional evolution, and tectonic controls. This study integrates seismic interpretation, structural restoration, petrographic analysis, and well data to reconstruct the tectono-stratigraphic architecture of the Tupi Field, Santos Basin, and assess its implications for reservoir compartmentalization and fluid flow dynamics.</div><div>The results indicate that the Tupi High functioned as a persistent structural high throughout successive rifting episodes, controlling sediment distribution and basin compartmentalization. During Rift II, an increase in crustal stretching toward the south played a key role in generating erosional or non-depositional features in northern sectors. Structural restoration and interpreted subsidence patterns support a continued tectonic influence during Rift III, extending fault activity into the upper Barra Velha Formation (BVF). These findings also reveal that deposition occurred across a mosaic of shallow, interconnected lakes, rather than a single large lacustrine system.</div><div>The diagenetic evolution of the BVF is marked by early calcite cementation, multiple dissolution episodes, dolomitization, and later silica cementation. Diagenetic patterns are primarily governed by sedimentary facies and stratigraphic position, but are also influenced by structural architecture. Mud-rich, low-permeability intervals exhibit dominant early diagenetic features with limited mineral replacement, whereas structurally elevated zones show intense late-stage diagenesis—including saddle dolomite, late dissolution, and hydrothermal quartz—associated with fault-related fluid circulation. Continued fault activity up to the top of Rift III likely enhanced vertical fluid migration. A south-to-north gradient in subsidence may have promoted fluid expulsion toward structurally higher domains post-deposition. Local controls, such as original mineralogy, facies interbedding, and porosity variability, further contributed to the observed heterogeneity.</div><div>These findings demonstrate that BVF reservoir quality reflects the multiscale interplay between depositional and tectonic architecture, early and late diagenetic processes, and post-depositional fluid dynamics—critical factors for pre-salt exploration and production strategies.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105733"},"PeriodicalIF":1.5,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852732","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":"Oxyodontherium zeballosi Ameghino, 1883 (Panperissodactyla, Litopterna, Macraucheniidae) from the Neogene of Uruguay","authors":"A. Corona,&nbsp;A.C. Badín,&nbsp;D. Perea","doi":"10.1016/j.jsames.2025.105730","DOIUrl":"10.1016/j.jsames.2025.105730","url":null,"abstract":"<div><div>Macraucheniidae comprises middle to large-sized herbivores characterized by an elongated skull, neck, and limbs. Diagnostic features of the family include a mesaxonic foot with three functional digits, a vertebral artery canal passing through the neural arch of most cervical vertebrae, and a third trochanter on the femur. This contribution provides a full comparative description of a macraucheniid mandible from an adult specimen recovered from Neogene strata in Kiyú, San José Department, Uruguay. The specimen exhibits several features consistent with an assignment to <em>Oxyodontherium zeballosi</em>, as follows: the m1 and m2 with fairly acute labial edges of mesial and distal lobes; talonid wider than trigonid, with thin entoconid linked to the hypolophid by an entolophid; hypolophid long and oblique; m3 with shorter trigonid, wide ectoflexid, and no entoconid non entolophid; low mandibular ramus of uniform high from anterior to posterior end. For further comparisons, an analysis of the holotype of <em>Oxyodontherium zeballosi</em> was performed using CT scans. This new specimen is significant because it represents the most complete mandible of the species reported to date, substantially improving our morphological knowledge. Additionally, it constitutes the first reliable record of <em>O. zeballosi</em> in Uruguay, extending the species geographic distribution to its most southeastern boundary. This species, previously reported only from Entre Ríos and San Luis provinces in Argentina, increases the known macraucheniid diversity in the Neogene of Uruguay, which is currently under investigation.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"166 ","pages":"Article 105730"},"PeriodicalIF":1.5,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144866560","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":"Tectonic influence and isotopic signature of pre-salt lacustrine carbonates in the Tupi field, Santos Basin","authors":"Deniro Costa ,&nbsp;Tiago Novo ,&nbsp;Tobias Fonte-Boa ,&nbsp;Ross Stevenson ,&nbsp;Humberto Reis ,&nbsp;Galen Halverson","doi":"10.1016/j.jsames.2025.105734","DOIUrl":"10.1016/j.jsames.2025.105734","url":null,"abstract":"<div><div>Fault networks in the Santos Basin play a key role in controlling depositional environmental conditions for sedimentation of the Barra Velha Formation. This work investigates how fault activity and reactivation affect the pre-salt carbonates and influence element distribution, integrating seismic interpretation, structural restoration and geochemical analyses for major elements (Ca, Mg, Sr, Fe, Mn) and isotopes (δ¹³C, δ¹⁸O, ⁸⁷Sr/⁸⁶Sr). Results reveal three dominant fault sets (NNW-SSE, N-S, NNE-SSW), with significant deformation in the central sector of the Iracema region indicated by section restoration. Isotopic data of δ¹³C (0.79 ‰–3.16 ‰) and δ¹⁸O (−1.22 ‰–3.86 ‰) from the studied well are consistent with other fields in the basin, which reflects that regional control overcomes local tectonic impact on deposition. However, the lacustrine depositional setting is described with episodic environmental changes as Fe and Mn present extreme outlier values and faults may influence Sr mobilization in fluid migration. The ⁸⁷Sr/⁸⁶Sr values (0.7130–0.7144) suggest a dominant felsic continental source, with minor volcanic input. These findings reinforce the role of faulting in controlling element mobility and the structural evolution of pre-salt carbonates in the Tupi field.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"165 ","pages":"Article 105734"},"PeriodicalIF":1.5,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144829546","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}