Journal of South American Earth Sciences最新文献

{"title":"Basin-scale sequence stratigraphy of the Vivian Formation (Marañón Basin, Peru)","authors":"Oscar López-Gamundí ,&nbsp;Cecilia López-Gamundí","doi":"10.1016/j.jsames.2026.105999","DOIUrl":"10.1016/j.jsames.2026.105999","url":null,"abstract":"<div><div>The Upper Cretaceous (Campanian–Maastrichtian) Vivian Formation sandstones form the main hydrocarbon reservoirs of the Marañón Basin in northern Peru. Extensive drilling has enabled detailed analysis of gamma-ray (GR)-based electrofacies, revealing their stratigraphic and depositional evolution. The Vivian Formation is situated unconformably above marine carbonates of the Chonta Formation and is overlain by the marine shales of the Cachiyacu Formation. Together, these units constitute the Vivian–Cachiyacu succession, which represents a deepening-upward sequence. Internally, the Vivian Formation represents a third-order sequence subdivided into three GR-based units: (i) a lower sand-rich interval (Vivian A) with blocky and bell-shaped motifs, (ii) a muddier, irregular intermediate interval, and (iii) an upper sand-rich interval (Vivian B) with blocky to serrated funnel-shaped motifs. This tripartite subdivision is recognized in central and distal basin areas, whereas the margins show a simpler, sandstone-dominated package interpreted as low-sinuosity fluvial deposits. The upper Vivian is overlain by the Cachiyacu shales sharply to gradationally, sometimes with intervening thin serrated bell-shaped successions. Analysis shows that the Vivian third order sequence records complete lowstand (LST), transgressive (TST), and highstand (HST) tracts. A thin, wave-reworked sandstone interval at the top, traditionally considered part of the Vivian Formation, is reinterpreted as the basal interval of the Cachiyacu major marine transgression. Compositionally, Vivian sandstones are quartz-rich (&gt;80%) and cratonic in origin. Porosity decreases predictably with depth due to overburden stress, but anomalously high porosities (8–10% above trend) appear in thin, fining-upward sandstones (Situche 1X) or isolated sands in a marine heterolithic succession (Tanguitza 1X) in the upper Vivian interval. This increased porosity is linked to wave reworking.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105999"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385920","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":"Impact of machine-learning phase picking on seismic tomography at Popocatépetl Volcano, Mexico","authors":"Karina Bernal-Manzanilla ,&nbsp;Marco Calò","doi":"10.1016/j.jsames.2026.105996","DOIUrl":"10.1016/j.jsames.2026.105996","url":null,"abstract":"<div><div>Machine-learning (ML) algorithms are increasingly used to build seismic catalogs. However, their transferability and impact on downstream applications remain uncertain. Here, we evaluate how ML-based phase picking and association affect local earthquake tomography at Popocatépetl Volcano, Mexico, one of the most active and hazardous volcanoes in North America. We tested multiple pipelines that combine the PhaseNet neural network—trained on publicly available datasets—with two phase associators, GaMMA and PyOcto. These pipelines were used to generate fully automatic catalogs of volcanic earthquakes. The pipelines show substantial variability in detection rates and in the spatial distribution of seismicity. This reflects how transferability depends on both the training context and the association algorithm. To overcome these limitations, we built a hybrid catalog using a systematic workflow that merged high-quality events from different pipelines, yielding the most complete dataset suitable for high-resolution seismic tomography. The resulting three-dimensional Vp, Vs, and Vp/Vs models reproduce several structures reported in previous tomographic studies and extend the resolvable volume to greater depths beneath the volcano. They reveal the presence of a vertically organized magmatic system composed by at least two high-Vp/Vs regions separated by a low-Vp/Vs in the firsts 18 km of the crust. We interpret these structures as two crystal-mush reservoirs connected by a volatile-bearing layer. Our results demonstrate that carefully constructed ML-based catalogs can reliably support high-resolution seismic imaging in complex volcanic settings.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105996"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385926","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":"Magma storage conditions of Navidad cone and its relation with the latest eruptions of Lonquimay volcano, Andean Southern Volcanic Zone","authors":"Soledad Riquelme-Ríos ,&nbsp;Inés Rodríguez ,&nbsp;Benigno Godoy ,&nbsp;Osvaldo González-Maurel ,&nbsp;Petrus le Roux ,&nbsp;Elisa Ramírez ,&nbsp;Harri Geiger ,&nbsp;Aracelly Acuña ,&nbsp;Gabriela Guzmán-Marusic ,&nbsp;Scarlett Chanqueo","doi":"10.1016/j.jsames.2026.105975","DOIUrl":"10.1016/j.jsames.2026.105975","url":null,"abstract":"<div><div>The Lonquimay-Tolguaca Volcanic Complex is constituted by Lonquimay volcano and Cordón Fisural Oriental, including the Navidad cone. An initial emplacement at 35–40 km depth, with different levels of crustal storage during ascent is proposed for Loquimay volcano. However, even though Navidad cone is in the vacinity of Loquimay volcano, a detailed relationship between the evolution and magmatic plumbing system of both volcanic structures is missing.</div><div>Considering its historical record (eruption occurred in 1988–1990), the Navidad cone is proposed to represent the active system of the Lonquimay Volcanic Complex, becoming an important target when trying to understand the active volcanic system of the SVZ. Therefore, the goal of this study is to determine the magmatic relationship between the Navidad cone and Lonquimay volcano, through various techniques, with a main focus on pyroxenes.Petrographically lavas from the last products of Lonquimay volcano (i.e. Lonquimay 5) show plagioclase, clinopyroxene, orthopyroxene and olivine phenocrystals, whilts orthopyroxene are absent at Navidad. Our geochemical data show that samples from Navidad are mainly andesitic, with some trachy-andesitic and trachytic compositions, whilst lavas from unit Lonquimay 5 vary from basaltic-andesite to andesite. Groundmass from Navidad has a trachy-andesite composition, whilst from Lonquimay 5 is mainly andesitic. Decreasing FeOt and MgO content with differentiation, and constant ⁸⁷Sr/⁸⁶Sr ratios (0.703960–0.703990) suggest that fractional crystallization controlled the magma evolution at both volcanic structures, with increasing ⁸⁷Sr/⁸⁶Sr ratios with differentiation suggesting more assimilation of crustal material for Lonquimay volcano.</div><div>Different thermobarometers were used for determining pre-eruptive conditions for Navidad (2–8 kbar; 1019–1068 °C), compared with those of Lonquimay volcano (0–8 kbar; 994–1150 °C). For both systems, magma ascent to chambers located at 6, 13, 17 and 22 km, connected by dikes or fissures. However, the petrographic and the geochemical signatures suggest that, even though the magmatic system feeding the volcanoes involved magma storage at similar depths, the feeding systems of Lonquimay volcano and Navidad acted slightly independently from each other.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105975"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098575","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":"Geophysical approach of the Paraná basin, by using 2.5D forward modeling of magnetic and gravity data","authors":"M.L. Pinto ,&nbsp;R.M. Vidotti ,&nbsp;E.S.F. Martins","doi":"10.1016/j.jsames.2026.105994","DOIUrl":"10.1016/j.jsames.2026.105994","url":null,"abstract":"<div><div>The tectonic framework of the Paraná Basin has been studied using a variety of geophysical methods. In recent years, the Brazilian National Agency for Petroleum, Natural Gas and Biofuels (ANP) has made its high-resolution aerogeophysical surveys (magnetic and gravity databases) of the onshore Brazilian sedimentary basins freely available. These data were used to perform 2.5D forward modeling, providing an updated geophysical framework of the Paraná Basin, particularly with respect to the major crustal domains and large fault systems. Our modeling refined the structural framework of the basin, density and magnetic susceptibility distributions, and the boundaries and crustal thicknesses of the Tocantins Province, Mantiqueira Province, Paranapanema Block, Rio Apa Block, and the São Francisco Paleocontinent. In the modeled sections, Moho depth ranges from 33 to 45 km (estimated values). Crustal discontinuities are associated with the Transbrasiliano strike-slip system, the Paraíba do Sul strike-slip system, and the Brasília Belt (Campo do Meio) thrust-fault system. The Transbrasiliano strike-slip system extends to depths of approximately 30 km and separates the Paraguay and Araguaia belts, as well as the Rio Apa and Paranapanema blocks. The Paraíba do Sul strike-slip system reaches depths of about 44 km and separates the Paranapanema Block from the Ribeira Belt. The Brasília Belt thrust-fault system extends to around 40 km depth and marks the boundary between the Goiás Magmatic Arc and the Brasília Belt/São Francisco Paleocontinent. The integration of geological and geophysical data provides a more detailed understanding of the Paraná Basin than previous studies, offering new insights into the evolution of Western Gondwana.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105994"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385432","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":"Formation of smectite from weathered Archean rocks","authors":"J.H. de Araujo ,&nbsp;M.F. Ginani ,&nbsp;F.A.B. de França ,&nbsp;L.C. de Souza","doi":"10.1016/j.jsames.2026.105980","DOIUrl":"10.1016/j.jsames.2026.105980","url":null,"abstract":"<div><div>X-ray diffraction, Thermal gravimetry analysis (TGA) measurements and chemical analysis have been conducted on samples of a green clay and host Archean rocks outcropping in a weathering profile, on Sabino mount, a region located near São Pedro do Potengi city-RN-Brazil. The results indicate that the Sabino mount green clay can be classified as a chromium montmorillonite. The origin of the clay is attributed to weathering caused of hydrothermal activity confirmed by the high chemical index of alteration (CIA) presented by the samples. The clay shows chemical relationships with the composition of the host rocks. The elements Fe, Ti and Cr, in the host rocks may be indicative of the primary genesis of the Monte Sabino clay.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105980"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175029","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":"Facies and stratigraphic characterization of the Lower–Middle Devonian of the eastern Parnaíba Basin: Implications for paleoenvironmental changes in an epicontinental sea","authors":"Thamara Welle Rodrigues Barbosa Van ,&nbsp;Mario Ferreira de Lima Filho ,&nbsp;Sonia Agostinho ,&nbsp;Zenilda Vieira Batista ,&nbsp;Emmanuel Franco Neto ,&nbsp;Bruno Caetano dos Santos","doi":"10.1016/j.jsames.2026.105993","DOIUrl":"10.1016/j.jsames.2026.105993","url":null,"abstract":"<div><div>The Parnaíba Basin developed over the continental basement during the stabilization of the South American Platform, along with other sedimentary basins. Within this framework, the Itaim, Pimenteira, and Cabeças formations represent the Lower and Middle Devonian intervals. A major flooding event during this period initiated a transgressive–regressive cycle of Eo-Eifelian to Eo-Givetian age, encompassing the entire Itaim and Pimenteira formations, as well as the basal portion of the Cabeças Formation. This study analyzes facies variations, depositional systems, stratigraphic surfaces, and mineralogical composition of the Pimenteira Formation, contributing to the paleoenvironmental understanding of the basin, with focus on areas within Picos, Pimenteiras, and São Miguel do Tapuio, Piauí State, Brazil. The Itaim Formation consists predominantly of fine-grained to very fine-grained sandstones with hummocky and tabular cross-stratification, shales, and siltstones. The Pimenteira Formation is mainly composed of fine-grained sandstones with sigmoidal and tabular cross-stratification, heterolithic shales, siltstones, and ferruginous lenses. Its contact with the Itaim Formation is marked by a maximum flooding surface, whereas the transition to the Cabeças Formation occurs through interdigitation of medium-grained sandstones and heterolithic shales of the Passagem Member. The presence of twenty facies, arranged in six depositional sequences, reveals a complex paleoenvironmental evolution marked by transitions between offshore, shoreface, and mouth bar settings, under storm influence and climate fluctuations that continually modified the wave base. Facies analysis of the Itaim, Pimenteira, and Cabeças formations indicate that the sediments were deposited in transitional environments with deltaic influence, evolving into shallow marine platform conditions dominated by storm-related processes.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 105993"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385918","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":"Multidisciplinary analysis of the structural controls on the Talacasto geothermal system, San Juan, Argentina","authors":"Gabriela Alvarez ,&nbsp;Franco E. Mancini ,&nbsp;Aixa L. Rodríguez ,&nbsp;Héctor P.A. García","doi":"10.1016/j.jsames.2026.106003","DOIUrl":"10.1016/j.jsames.2026.106003","url":null,"abstract":"<div><div>The Talacasto geothermal system, located in the eastern part of the Central Precordillera in San Juan, Argentina, has received little multidisciplinary attention despite its hydrothermal manifestations. This study integrates digital elevation models (DEMs), aeromagnetic data, and hydrographic analyses to characterize the structural controls that influence fluid circulation in the area. Structural mapping, supported by geophysical filters, revealed a complex network of lineaments dominated by N-S thrusts, with secondary NE–SW and NW–SE orientations. Fracture intensity and connectivity maps highlight zones of enhanced permeability, which coincide with the location of known thermal springs. Hydrographic analysis delineated three major drainage basins that contribute to the Talacasto springs. The convergence of surface drainage with tectonic structures indicates strong coupling between surface water recharge and subsurface fluid flow. A schematic 3D model suggests that meteoric waters infiltrating from the western catchment cross the Talacasto Range through fractured limestones and Neogene sediments, ascending along the Talacasto Fault where they emerge as thermal springs. These results demonstrate that the geothermal system is structurally controlled, with fault intersections acting as preferential pathways for fluid migration. This study represents the first multidisciplinary characterization of the Talacasto system and provides insights for evaluating its geothermal potential.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 106003"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385922","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":"Stratigraphic review of the Permian Santa Brígida formation, in the Recôncavo-Tucano-Jatobá Rift","authors":"U.C.F.F. Brito Conceição ,&nbsp;C.F.A. Rodrigues ,&nbsp;R. Dino ,&nbsp;L.S.G. Teixeira ,&nbsp;O.M.C. Oliveira ,&nbsp;M.J. Lemos de Sousa ,&nbsp;A.F. Brito","doi":"10.1016/j.jsames.2026.106007","DOIUrl":"10.1016/j.jsames.2026.106007","url":null,"abstract":"<div><div>The Santa Brígida Formation, located in the Recôncavo-Tucano-Jatobá Rift system, plays a crucial role in understanding the Permian tectono-sedimentary evolution of northeastern Brazil. Despite extensive research, there are still uncertainties regarding how it differs from adjacent units, such as the Afligidos Formation, which affect palaeoenvironmental interpretations and hydrocarbon exploration. This study provides a detailed stratigraphic review, integrating palynological and regional stratigraphic interpretations to clarify the relationship between the Afligidos and the Santa Brígida formations, as well as their respective depositional settings. The Santa Brígida Formation consists of two lithostratigraphic subdivisions: the Caldeirão and Ingá members. The Ingá Member, in particular, shows significant potential for hydrocarbon generation. Palynological data from this unit reveal the presence of both <em>Protohaploxypinus</em> sp. and <em>Lueckisporites virkkiae</em>, confirming its Permian age. The present study proposes stratigraphic standardisation and recommends unifying the Afligidos and Santa Brígida formations under the name Santa Brígida Formation of the Permian of the Recôncavo-Tucano-Jatobá Rift system, due to their lithological and chronostratigraphic equivalence. This revision improves the geological framework of the Recôncavo-Tucano-Jatobá Rift system, highlighting the Santa Brígida Formation as a key unit for hydrocarbon exploration. Furthermore, the oil-generating potential of outcropping samples underscores its economic significance, providing a solid foundation for future regional oil and gas exploration assessments.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"174 ","pages":"Article 106007"},"PeriodicalIF":1.5,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147385908","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":"Corrigendum to ‘Structural control and deformational evolution of the São Francisco gold deposit, Borborema Province (NE Brazil)’ [J. S. Am. Earth Sci. 172 (2026) 105934]","authors":"Harrizon Lima de Almeida ,&nbsp;Jucieny Sousa de Moura Barros","doi":"10.1016/j.jsames.2026.105960","DOIUrl":"10.1016/j.jsames.2026.105960","url":null,"abstract":"","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"173 ","pages":"Article 105960"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190597","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":"Biochronocorrelation of K/Pg-Danian sections near Chicxulub: application of new planktic foraminiferal scales","authors":"Ignacio Arenillas ,&nbsp;Vicente Gilabert ,&nbsp;Iván Aparicio ,&nbsp;Hermann D. Bermúdez ,&nbsp;Liliana Bolívar ,&nbsp;Thierry Calmus ,&nbsp;Daniel Ferrer ,&nbsp;José M. Grajales-Nishimura ,&nbsp;Carlos L. Liesa ,&nbsp;Kenya E. Núñez-Cambra ,&nbsp;Ligia Pérez-Cruz ,&nbsp;Reinaldo Rojas-Consuegra ,&nbsp;María del Carmen Rosales-Domínguez ,&nbsp;Ana R. Soria ,&nbsp;Jaime Urrutia-Fucugauchi ,&nbsp;José A. Arz","doi":"10.1016/j.jsames.2026.105959","DOIUrl":"10.1016/j.jsames.2026.105959","url":null,"abstract":"<div><div>Using qualitative and quantitative planktic foraminiferal stratigraphy, we correlated the Danian sediments directly overlying the Chicxulub impact-related Cretaceous/Paleogene boundary deposits (K/Pg deposits) at localities across the Gulf of Mexico, the Caribbean, and the Colombian Pacific. The aim of this study was to apply recently developed planktic foraminiferal biochronological scales to determine whether these American K/Pg sections record continuous stratigraphic succession or show evidence of a hiatus between the K/Pg deposits and the first Danian sediments deposited under normal conditions (K/Pg-Danian hiatus). To accomplish this, we reviewed, completed, and updated biostratigraphic information generated over the last three decades, incorporating new data from thirty K/Pg sections. This effort resulted in a highly comprehensive biostratigraphic database for the lower to upper Danian across the studied regions. Leveraging this database, we developed two biochronological scales with a higher resolution than the more standardized scale by extending the Dan-achrozonation and the DanAZ-acmezonation of Arenillas et al. (2021)into the middle-upper Danian. These new planktic foraminiferal scales enable the estimation of stratigraphic continuity in the K/Pg sections or, where applicable, the temporal duration of the K/Pg-Danian hiatuses. We conclude that, among the sections studied, only Bochil and Guayal (Mexico), Moncada (Cuba), Beloc HA, Nan Pak and Roche à Pierre (Haiti), and probably Isla Gorgonilla (Colombia) exhibit stratigraphic continuity between the K/Pg deposits and the first normal Danian sediments.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"173 ","pages":"Article 105959"},"PeriodicalIF":1.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080255","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}