Journal of South American Earth Sciences最新文献

{"title":"Tahnaichthys magnuserrata gen. and sp. nov., a double-hump pycnodontid (Actinopterygii, Pycnodontiformes) fish from the Albian limestones of the Tlayúa Quarry, Puebla, Mexico","authors":"Stephanie Pacheco-Ordaz ,&nbsp;Omar Mejía ,&nbsp;Jesús Alvarado-Ortega","doi":"10.1016/j.jsames.2024.105277","DOIUrl":"10.1016/j.jsames.2024.105277","url":null,"abstract":"<div><div><em>Tahnaichthys magnuserrata</em> gen. and sp. nov. is described here based on three well-preserved Albian specimens recovered in the lagoon-coastal deposits of the Tlayúa Quarry, Puebla, Mexico. This species belongs to the order Pycnodontiformes and shows the diagnostic features of the family Pycnodontidae, including the presence of a posterior parietal process distally branched, toothless reniform maxilla, anterior thin wings at the base of the haemal and neural spines, and slender dentary with two teeth. In addition, this species shows unique features never observed before in other pycnodontids as the presence of two unequal predorsal humps or prominences, including a slight hump just behind the occiput and a large hump rising in front of the dorsal fin. The predorsal scutes are thick, have a longitudinal row of unequal spines, and show thin lateral wings projected ventrally, covering a large part of the predorsal trunk region. In the new species, the modified bar-like scales of the predorsal region have tiny posterior wings ornamented with tubercles scattered or arranged in dorsoventral short ridges. In addition, the premaxilla of this new species is ventrally broad and has a large single incisiform tooth opposing two small, oval dentary teeth. This new species exhibits a peculiar mixture of osteological features that, for the moment, complicate its taxonomic designation at the suprageneric level (subfamily or tribe). Although this is the second pycnodontiform species from Tlayúa formally described, the present discovery increases the taxonomic diversity of the pycnodontids in North America and the Paleogulf of Mexico domain.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105277"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181199","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":"Soil frequency assessment in the eroded cliffs of Mendoza River terraces, Argentina: Implications for the landslide hazard and urban planning","authors":"Francisco A. Calderón ,&nbsp;Stella M. Moreiras ,&nbsp;Javier Oropeza ,&nbsp;Sebastián Vía ,&nbsp;Emilce Giolo ,&nbsp;Alfredo Cueto ,&nbsp;Sebastian Panella ,&nbsp;Carlos Frau","doi":"10.1016/j.jsames.2024.105321","DOIUrl":"10.1016/j.jsames.2024.105321","url":null,"abstract":"<div><div>This paper provides an in-depth examination of the natural soil frequencies in cliffs on the northern and southern terraces of the Mendoza River in Mendoza province, Argentina (32°S), where slope instability events have been recorded. However, in the last five years, there has been a booming and worrying trend of unregulated urbanization, with buildings being constructed just a few meters from the cliff edges. This critical situation increases the area's vulnerability to slope instability. The cliffs are potentially unstable due to low-intensity earthquakes and soil saturation. The study passively monitor the terrane by soil frequencies to delineate safe or stable zones, thus reducing exposure and the consequent risk of landsliding. We used the H/V spectral ratio method to determine the dominant soil frequencies. We did this by measuring ambient vibrations using digital accelerometers. The results were interpreted in the context of the geological characterization of the eroded cliffs along the Mendoza River terraces. Additionally, the directional variation of the frequencies was analyzed. The findings reveal frequency anomalies indicating landslide hazards in areas close to cliffs where previous collapses and landslides have been recorded. These results demonstrate the significant hazard associated with slope instability, supporting the adoption of regulatory and preventive measures in land use planning for the study area.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105321"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181774","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":"First record of a Notoungulata (Mammalia) from the Late Miocene of Quebrada La Troya, Toro Negro Formation, Vinchina, La Rioja: Taxonomy and aleoecological notes","authors":"Damián Ruiz-Ramoni ,&nbsp;Matías A. Armella ,&nbsp;Esperanza Cerdeño ,&nbsp;Patricia L. Ciccioli","doi":"10.1016/j.jsames.2024.105298","DOIUrl":"10.1016/j.jsames.2024.105298","url":null,"abstract":"<div><div>The extinct herbivorous mammals of the order Notoungulata hold significant importance in the South American fossil record, showcasing a wide range of sizes and forms. In La Rioja Province, northwestern Argentina, at the Quebrada La Troya locality, Vinchina Department, the Toro Negro Formation has revealed the first notoungulate remains of a single individual, PULR-V 222. It is identified as <em>Hemihegetotherium achathaleptum</em> (Hegetotheriidae) with an estimated body mass of 18.6–28.9 kg. The Toro Negro Formation has a low proportion of notoungulate fossils compared to other taxa, such as rodents, cingulates, and especially sloths, which differs from other coeval formations. This disparity suggests different environmental conditions during the Late Miocene. The underrepresentation of notoungulates in the Toro Negro Formation may be due to various factors, including ecological conditions and sampling biases, though the latter is not firmly supported. Additionally, PULR-V 222 exhibits hypothesized predation marks, likely made by large vertebrate predators such as the armadillo <em>Macroeuphractus</em>, sparassodonts, or contemporaneous carnivorans. This study emphasizes the need for further exploration in the Toro Negro Formation to better understand the taphonomy and ecological dynamics affecting the notoungulate representation.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105298"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180729","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":"Sediment provenance signal of the Northern Andes during the Oligocene-Pliocene: Insights from the detrital record of the forearc and intra-arc basins, northwestern Colombian margin","authors":"Sebastián Echeverri ,&nbsp;Sergio A. Celis ,&nbsp;Andrés Pardo-Trujillo","doi":"10.1016/j.jsames.2024.105316","DOIUrl":"10.1016/j.jsames.2024.105316","url":null,"abstract":"<div><div>The Cenozoic uplift and relief history of the Colombian Andes controlled the evolution of drainage systems and the filling history of sedimentary basins. The understanding of the associated polyphasic orogenic history has been reconstructed from the history of hinterland and foreland basins in eastern Colombia. In contrast, the tectonostratigraphic record of the forearc and intra-arc basins is less known, despite their potential to record both the exhumation and magmatic history of the orogen and the lesser-known history of the Central and Western cordilleras. A review of the regional stratigraphy together with provenance constraints from sandstone petrography, and U-Pb zircon geochronology a (n = 2738 new and 2456 published data) of the Oligocene-Pliocene successions in the Caribbean and Pacific forearc basins and the Amagá and Cauca intra-arc basins (NW Colombia) is used to infer the topographic evolution of the Central and Western cordilleras, as well as the distribution of depositional environments and ancient drainage systems. The results indicate that the Oligocene-Lower Miocene sandstones of the intra-arc and Caribbean forearc basins document the uplift of both the Central and Western cordilleras, as seen by the quartz-rich character with fragments associated to the Pre-Cenozoic sources, while sandstones of the Pacific forearc segment show a lithic character with volcanic fragments derived from the Cretaceous and Eocene-Oligocene sources of the proto-Western Cordillera. After the Lower-Middle Miocene, sandstones are more immature including sources derived from the cordilleran basement and volcanic fragments from the upper Oligocene-Middle Miocene magmatic arc located exclusively in the Western Cordillera. The Upper Miocene-Pliocene sandstones in general exhibit a lithic character with fragments derived from upper Oligocene-Middle Miocene and Middle Miocene-Pliocene magmatic rocks located in the Western Cordillera and intra-arc region. When the provenance record between basins is compared, changes in topographic continuity are seen through time, with some marine passages connecting the Pacific forearc with the Cauca intra-arc basin during the Oligocene-Miocene, followed by the formation of a continuous cordilleran system after the Middle Miocene that interrupts marine passages. The integrated detrital zircon signature from the different basins show that within a regional perspective, Miocene-Pliocene magmatism was continuous along the northwestern South American margin.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105316"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180731","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":"Performance and sensitivity analysis of the Morpho2DH model in extreme events in southern Brazil","authors":"Alessandro Gustavo Franck,&nbsp;Masato Kobiyama","doi":"10.1016/j.jsames.2024.105275","DOIUrl":"10.1016/j.jsames.2024.105275","url":null,"abstract":"<div><div>Debris flows are a mixture of water and sediment with a continuous fluid behavior driven mainly by gravity. Computational modeling can be used to predict areas susceptible to these phenomena. When using computational modeling, sensitivity analysis is a crucial step to evaluate and interpret the model results. Thus, the objective of this study was to evaluate the performance of the Morpho2DH debris flow model, perform a sensitivity analysis of its input parameters, recommend application criteria, and increase the use of such a model in South America and Brazil. The model was applied in two representative areas with occurrences of debris flows in southern Brazil. The methodology consisted of two steps: (i) model calibration; (ii) one-at-a-time (OAT) sensitivity analysis (SA) for selected input parameters. The sensitivities of input parameters were evaluated for total area affected, distance traveled, mean velocity, and deposited volume. The results of the SA demonstrate that the most sensitive parameters were maximum bed erosion depth, resistance coefficient, minimum flow depth, and mean particle diameter. Meanwhile, static bed sediment concentration, vegetation, and internal friction angle showed moderate sensitivity. Parameters such as liquid density, sediment concentration, and sediment density showed the lowest sensitivities. Finally, it is recommended to use the model for situations where input volume and terrain data (mainly the erosion thicknesses or soil depth) are well-defined. Additionally, the computational cost of this model should be considered, concerning the magnitude of the event to be simulated.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105275"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181200","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":"Machine learning driven multi-hazard risk framework for coastal resilience","authors":"Palanikkumar D ,&nbsp;Mashael Maashi ,&nbsp;Jamal Alsamri ,&nbsp;Marwa Obayya","doi":"10.1016/j.jsames.2024.105331","DOIUrl":"10.1016/j.jsames.2024.105331","url":null,"abstract":"<div><div>Coastal cities are increasingly vulnerable to climate-induced hazards, including sea-level rise, storm surges, coastal erosion, and extreme weather events. Buenos Aires, located along the Río de la Plata estuary, faces significant risks due to its dense population, vital infrastructure, and dynamic coastal environment. This study proposes a multi-hazard risk analysis framework, leveraging machine learning algorithms to model and predict risks in Buenos Aires’ coastal zones. Our approach integrates various datasets, including historical weather patterns, topographical and bathymetric data, urban development indices, and socio-economic factors, to assess hazard impacts' spatial and temporal distribution. The framework employs machine learning, specifically Random Forest (RF), to classify hazard-prone zones based on historical patterns and projected climate scenarios. The models are trained on datasets spanning the past three decades, capturing shifts in storm intensity, precipitation, and land use. Furthermore, Principal Component Analysis (PCA) is used to reduce data dimensionality and highlight key predictors of risk. By mapping hazard probabilities across different zones, our framework offers a nuanced view of hazard susceptibility, enabling local authorities to prioritize resources and adapt policies accordingly. This framework also introduces a novel adaptive learning component, where model parameters are periodically updated based on new environmental and urbanization data, ensuring that risk assessments remain relevant amidst changing climate conditions. Through this predictive model, stakeholders can anticipate hazard-prone areas, improving resilience planning and response mechanisms. This study thus provides a scalable, data-driven approach for addressing multi-hazard risk in Buenos Aires and offers insights into adaptive risk management strategies for coastal cities facing similar challenges globally.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105331"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181777","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":"Refining metamorphic-time paths with deformation conditions: The exhumation history of the southernmost part of Brasília Orogen, Brazil","authors":"Rafael Gonçalves Motta ,&nbsp;Renato Moraes","doi":"10.1016/j.jsames.2024.105324","DOIUrl":"10.1016/j.jsames.2024.105324","url":null,"abstract":"<div><div>In the southeastern Brazil, a thick section of lower crust crops out in the Socorro-Guaxupé Nappe, part of a Neoproterozoic orogenic collage in the southernmost part of the Brasília Orogen. Migmatites, predominantly diatexites, and granulites underwent ultra-high temperature conditions, reaching around 1000 °C and 10 kbar during their metamorphic peak. However, these rocks exhibit distinct structural characteristics within the studied area. Late-stage foliation in migmatites displays a more dispersed distribution with a predominant NW-SE orientation, whereas in granulites, the foliation predominantly trends in a WSW-ESE direction. Lineation in the migmatites is defined by feldspars and hydrated minerals, such as biotite and hornblende with a WNW-ESE direction, whereas in the granulites it is defined by anhydrous minerals like pyroxenes and feldspars, exhibiting a WSW-ENE orientation. The quartz c-axis fabric opening-angle for the residuum of granulite shows the highest values (135–154°), followed by the leucosome of granulites (113–130°) and then leucosome of migmatites (86–97°). This implies that the quartz c-axis fabric in granulites records two distinct temperature regimes: the residual portion aligns closely with the metamorphic peak temperatures, ranging between 869 and 923 °C, while another stage corresponds to temperatures near the crystallization point of the leucosome, ranging between 796 and 853 °C. The migmatites exhibit quartz c-axis fabric temperature between 633 and 685 °C. Therefore, the solid-state deformation in granulites occurred at higher temperatures compared to migmatites, which remained in suprasolidus conditions over a broader temperature range (&gt;300 °C). Thus, both units reached the metamorphic peak at same crustal level, but their exhumation histories are contrasting: while granulites were crystallized, migmatites remained partially molten, preserving distinct deformation geometries.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105324"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182205","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":"Neotectonics of Araripe basin near Patos shear zone and Araripe valley: Insights from geomorphometry","authors":"Viktor Ferreira de Oliveira,&nbsp;Wellington Ferreira da Silva Filho","doi":"10.1016/j.jsames.2024.105333","DOIUrl":"10.1016/j.jsames.2024.105333","url":null,"abstract":"<div><div>This study examines the tectonic activity in the northern segment of the Araripe Basin, located in southern Ceará state, NE Brazil, near the Patos shear zone, using morphometric indexes derived from SRTM imagery. The research integrates various morphometric parameters, including the Stream Length Gradient (SL), Asymmetry Factor (AF), Mountain-front Sinuosity (SMF), and Hypsometric Integral (HI), to develop a Composite Index of Tectonic Activity (CIT), which is further refined into the Relative Tectonic Activity Index (IAT), which indicates the degree of influence of tectonic activity on a given area. This approach facilitates a comprehensive assessment of tectonic processes and landscape evolution. The findings indicate that 26.75% of the studied region demonstrates a high IAT value, while 3.34% is categorized as very high. The majority of the area, encompassing 59.93%, shows medium tectonic activity. Through a combined analysis of these indexes and morphological assessments, which highlight the impact of horsts and grabens on the terrain, the study identifies areas most influenced by tectonic activity in shaping the landscape.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105333"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181772","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":"Soil attributes as proxies of anthropic influence in the floodplain of the Amazon Valley, Brazil","authors":"Carlos Ernesto G.R. Schaefer ,&nbsp;Kleberson Worsley Souza ,&nbsp;Hedinaldo Narciso Lima ,&nbsp;Wenceslau Geraldes Teixeira ,&nbsp;Guilherme Resende Corrêa","doi":"10.1016/j.jsames.2024.105314","DOIUrl":"10.1016/j.jsames.2024.105314","url":null,"abstract":"<div><div>Recent studies identified the presence of Amazonian Dark Earths (ADE - anthropogenic soils) at the floodplains, similarly to the well-known ADE of the upland. Previously, different parameters have been established for characterizing ADE anthropic horizons, but they are unlikely to be useful in ill-drained environments of the hydromorphic Amazon floodplain. It raises the question of to what extent can the established parameters of ADE be applied to anthropic horizons at floodplains, and what other characteristics or attributes could be used as criteria for identifying and classifying anthropic horizons in those environments. The main hypothesis is that the ADE are contrasting to typical ADE found in the uplands. So, we selected eleven representative soil profiles in the Amazon River floodplain between the cities of Coari and Careiro da Várzea, in the Amazonas State - Brazil. Soils were described, sampled and classified according to the Brazilian Soil Classification and the World Reference Base for Soil Resoucers (WRB) System. Morphological, chemical and physical attributes were described and determined. The results indicated that pH value, the organic C (OC) and Cu concentration can be characteristic for upland ADE, but not for the buried Anthrosols from the floodplain. The concentration of OC required by the IUSS Working Group WRB (2022) as one of the criteria for pretic horizon, was not reached in all soils, and some could not be considered an Anthrosol for having less than 0,6 % OC even though all other criteria were met. We postulate that this criteria should be changed in such a way that these soils classify as Anthrosols. However, other soil attributes normally used as indicators of anthropic influence on upland ADE are also noticed on floodplain soils such as: high available or total P (in Mehlich-1 or total), Ca (Ca²⁺ or CaO), Zn (Mehlich-1 or total). It was further observed that the total concentrations of Ba, Cu and Sr also proved to be good indicators of anthropic horizons of floodplains buried soils. Hence, differential soil attributes can be used as proxies of Anthrosols presence in Amazon floodplain soils, enlarging the extent of these soils in the Amazonian landscape.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105314"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182214","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 pluton-dike system as an incomplete assembled pluton: Field geology, petrography and geochemistry of the Rodríguez dike swarm and the Kranck pluton, Fuegian Andes","authors":"Mauricio González Guillot ,&nbsp;Pablo J. Torres Carbonell ,&nbsp;Sebastián J. Cao ,&nbsp;Rogelio D. Acevedo","doi":"10.1016/j.jsames.2024.105295","DOIUrl":"10.1016/j.jsames.2024.105295","url":null,"abstract":"<div><div>Dikes extending into the host-rock are a common feature at pluton roofs. Typically, the dikes are considered offshoots from differentiated magma reservoirs within the pluton, i.e. late-stage intrusions of the successive discrete magma pulses that built the pluton. We evaluate this hypothesis on a dike swarm and associated pluton, the Kranck-Rodríguez pluton-dike system, by analyzing its field geology, petrography and geochemistry (whole-rock and mineral). This system was emplaced in the shallow crust (∼1.7 kbar) within the fold-and-thrust belt of the Fuegian Andes. The Kranck pluton is a small (∼4.4 km²), composite body composed of a diverse range of lithologies, from mafic to felsic. Internal contacts are mainly sharp and subvertical, suggesting diking as a mode of assembly. The Rodríguez dike swarm extends up to 6 km from the pluton, mainly exposed adjacent to it. This swarm also displays a wide variety of lithotypes, encompassing a set of dikes affected by ductile deformation, and a younger set without it. Geochemical and petrographic analyses, along with thermobarometry, suggest that the Rodríguez dikes and lithotypes within the pluton were fed from different, deeper magma reservoirs, in an inferred trans-crustal plumbing system. We propose that the dikes represent discrete increments of the growing pluton, in a protracted process of successive injections. This ultimately led to the assembly of the pluton in the sector of the system with greater magma flux. The system developed in two major episodes, pre- and post-ductile deformation, each characterized by multiple, discrete magma injections. We consider this system as an embryonic stage of a broader model that would evolve from sheets separated by host-rock, to bodies with sheeted margins containing host-rock rafts, and eventually to relatively inclusion-free plutons, potentially forming larger bodies if provided with a greater magma supply and/or higher accretion rates.</div></div>","PeriodicalId":50047,"journal":{"name":"Journal of South American Earth Sciences","volume":"152 ","pages":"Article 105295"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181783","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}