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A new species, Ozarkodina huenickeni, from the upper Silurian - Lower Devonian in San Juan Precordillera, South America J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-14 María José Gómez; Ana Mestre; Carlo Corradini; Susana Heredia
The study on Silurian-Devonian conodonts from the Precordillera has shown a significant increase in the last 5 years. In the new conodont collections, particular specimens of Ozarkodina were obtained from the middle and upper parts of the Los Espejos Formation in the Talacasto region. The taxonomic study allows us to propose a new species of the genus Ozarkodina, named Ozarkodina huenickeni sp. nov
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Characterizing the nature and importance of lava-sediment interactions with the aid of field outcrop analogues J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-07 Natália Famelli; John M. Millett; Malcolm J. Hole; Evandro F. Lima; Isabela de O. Carmo; Dougal A. Jerram; David W. Jolley; Jessica H. Pugsley; John A. Howell
The emplacement of lava flows into poorly consolidated sediments during volcanism can lead to a wide range of lava-sediment interaction processes. Understanding these processes and their products is critical for appraising reservoir quality and connectivity in both intra- and sub-volcanic prospectivity settings. This study investigates the nature of lava-sediment interactions during the onset of magmatism
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Ostracods from the late Albian–early Cenomanian of the Sergipe–Alagoas Basin, Brazil: New taxonomic and biostratigraphic inferences J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-14 Bernardo Vázquez-García; Daiane Ceolin; Gerson Fauth; Leonardo Borghi; Bruno Valle; Aristóteles De Moraes Rios Netto
This paper presents new taxonomic reports and biostratigraphic inferences based on ostracods in the basal section of the cored well UFRJ-2-LRJ-01-SE, perforated in the Votorantim quarry, Sergipe-Alagoas Basin, Brazil. The studied material comprised 44 samples in the range 438.65 to 315.30 m, identifying 52 species of ostracods distributed in 31 genera and 16 families. Five new species are proposed:
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Rising from the ashes: The biggest South American deers (Cetartiodactyla: Cervidae) once roamed Northeast Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-16 Alline Rotti; Raúl Ignacio Vezzosi; Dimila Mothé; Leonardo dos Santos Avilla
The tragic fire at the National Museum (Brazil) in September 2018 caused invaluable losses to South American natural and cultural heritage. However, previous visits to the paleontological collection generated photographic and descriptive records of mammalian fossil specimens from the Pleistocene of Brazil. Thus, it was possible to redescribe and revise the taxonomy of Cervidae fossils from two important
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Age and geochemistry of Cambaí Complex, São Gabriel Terrane, Brazil: Arc-related TTG-like rocks J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-23 Rosemeri Soares Siviero; Olivier Bruguier; Luis A. D’ávila Fernandes; Edinei Koester; Carla Cristine Porcher; Gustavo Kraemer
The Cambaí Complex TTG-like rock assemblage representing a Neoproterozoic juvenile magmatic arc is part of the São Gabriel Terrane that crops out in the SW domain of the Dom Feliciano Belt in S-Brazil. Geochemistry of dioritic, tonalitic, trondhjemitic, and granodioritic rocks of this complex indicate their low-medium-K calc-alkaline geochemical affinity being metaluminous and with fractional crystallization
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The Piedras de Afilar Formation (Neoproterozoic, Uruguay): Sedimentology and provenance of a key unit for SW-Gondwana paleogeography J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-22 Karina Pamoukaghlián; Claudio Gaucher; Daniel G. Poiré; Robert Frei
The Piedras de Afilar Formation (PAFm) is a late Neoproterozoic sedimentary succession autochthonous to the Tandilia Terrane, part of the Río de la Plata Craton. It overlies with erosional unconformity a Paleoproterozoic igneous and metamorphic basement. According to facies analysis and lithostratigraphy, the PAFm is divided into three members for which detailed petrography, X-ray diffractometry and
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Pleistocene Ophiomorpha nodosa burrows from Buenos Aires, Argentina: Paleoenvironmental implications for ghost shrimp trace fossils along South America J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-22 Cristian A. Pereyra
Ophiomorpha nodosa Lundgren1891 is described from Puente de Pascua Formation Late Pleistocene of northeastern Buenos Aires province. The pelletal morphology and the base of ramifications of O. nodosa burrows are compared with mid-Holocene, Late Pleistocene Pehuen-Có locality and southern Brazil records. The preservation between sites differs in the degree of erosion and weathering, in situ or ex situ
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Applicability and performance of deterministic and probabilistic physically based landslide modeling in a data-scarce environment of the Colombian Andes J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-21 Roberto J. Marin; María Fernanda Velásquez; Oscar Sánchez
Physically based models have been widely used around the world to study landslide occurrence. The accuracy in a physically based landslide susceptibility/hazard assessment depends mostly on the input parameters. In this research study, three physically based models' applicability and performance were assessed using deterministic and probabilistic approaches. It was carried out in a data-scarce environment:
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Paleoenvironment and source-rock potential of the Cenomanian-Turonian Eagle Ford Formation in the Sabinas basin, northeast Mexico J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-21 Juan Josué Enciso Cárdenas; Fernando Núñez-Useche; Luis Fernando Camacho Ortegon; Genaro de la Rosa Rodríguez; Mario Martínez-Yañez; Ángeles Gómez Borrego
The Cenomanian-Turonian Eagle Ford Formation is a widespread organic-rich mudrock in Texas and northern Mexico. The economic significance of this unit for oil and gas production in USA has led to numerous investigations documenting its lithological and geochemical variability. Comparatively little is known about facies distribution and source rock potential of this unit in Mexico. Here, we studied
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Genesis and classification of carbonate soils in the State of Rio de Janeiro, Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-19 Carlos Roberto Pinheiro Junior; Marcos Gervasio Pereira; Antônio Carlos de Azevedo; Cornie Van Huyssteen; Lúcia Helena Cunha dos Anjos; Ademir Fontana; Eduardo Carvalho da Silva Neto; Jonas Nunes Vieira; Thairis Gomes Santos
Carbonate rocks occur in Brazil under diverse climatic and environmental conditions, and therefore are of great importance for pedological studies. The northwest region of the State of Rio de Janeiro, Brazil, is composed of calc-silicate rocks and marbles that occur under tropical climate with a long period of water deficit, which provides conditions for peculiar pedogenesis. The objective of this
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Crystallization ages of the basic intrusive Ediacaran magmatism in the southeastern Dom Feliciano Belt, southernmost Brazil: Implications in the belt geodynamic evolution J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-30 L. Dal Olmo-Barbosa; E. Koester; D.T. Vieira; C.C. Porcher; D.G. Cedeño
The participation of mantle-derived magmas, especially hydrous basaltic liquids, in the evolution of granitic belts in both orogenic and post-collisional environments is crucial to evaluate both mantle and crustal evolution, as well as the material transference processes between these two reservoirs. Besides, this transition in the geodynamic context creates specific conditions, promoting the generation
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Isotope stratigraphy of the uppermost Vazante Group, Brazil: Insights on paleoenvironments and regional correlation J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-15 Marcus Paulo Sotero; Fabrício de Andrade Caxito; Carlos José Souza de Alvarenga; Roberto Ventura Santos; Marco Aurélio Piacentini Pinheiro; Paulo Henrique Amorim Dias
Rocks of the Vazante Group in the Morro Agudo region (SE-Brazil) integrate a thick clay-carbonate sequence composed of twelve sedimentary facies and four facies associations (FAs), deposited in a mixed marine passive margin environment. This work carried out systematic isotope analyses of δ13C and δ18O on the two upper stratigraphic units of the Vazante Group (Morro do Calcário and Serra da Lapa formations)
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Mineralogy and geochemistry of a bauxite-bearing lateritic profile supporting the identification of its parent rocks in the domain of the huge Carajás iron deposits, Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-13 Leonardo Boiadeiro Ayres Negrão; Marcondes Lima da Costa
A bauxite-bearing lateritic profile, developed along a borehole within the supergenic Fe-deposits of the Carajás Mineral Province in Brazil, is investigated after its textural aspects, mineralogy, and geochemistry. Petrographic studies, XRD mineralogical analysis, SEM-EDS, and whole-rock chemistry were used to study selected samples. The 156 m depth borehole is composed of basaltic andesite at the
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U–Pb geochronology of the meta-volcanic rocks from Sierra de Calcatapul: Implications for the middle Triassic SYN-RIFT volcanism and tectonic evolution of northern extra-Andean Patagonia J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-16 Pablo D. González; Raúl E. Giacosa; Silvia Lagorio; Carlos Ballivian Justiniano; Ana M. Sato; M. Cecilia Cábana; Miguel A.S. Basei; Alicia Busteros; Diego Silva Nieto
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Dicynodonts (Therapsida: Anomodontia) of South America J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-15 Christian F. Kammerer; Maria de los Angeles Ordoñez
The dicynodont fauna of South America is comprehensively reviewed. Permian South American dicynodont body fossils are known only from the Rio do Rasto Formation of southern Brazil, and include a specifically uncertain representative of the trans-Gondwanan genus Endothiodon and the endemic Rastodon procurvidens. The majority of known South American dicynodonts are Triassic kannemeyeriiforms, with numerous
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Geological evolution of the Guallatiri volcano, Arica y Parinacota Region, northern Chile J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-31 José Pablo Sepúlveda; Felipe Aguilera; Manuel Inostroza; María Paz Reyes
Guallatiri volcano is an active stratovolcano located in the Arica y Parinacota Region of northern Chile. It belongs to the Central Volcanic Zone (CVZ) of the Andean range and is the youngest and southernmost volcano of the Nevados de Quimsachata volcanic chain. Guallatiri is an ice-capped volcano considered the third-highest risk center in northern Chile with a current activity characterized by two
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Spatio-temporal monitoring of soil and plant indicators under forage cactus cultivation by geoprocessing in Brazilian semi-arid region J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-10 Marcos Vinícius da Silva; Héliton Pandorfi; Gledson Luiz Pontes de Almeida; Renato Paiva de Lima; Anderson dos Santos; Alexandre Maniçoba da Rosa Ferraz Jardim; Mário Monteiro Rolim; Jhon Lennon Bezerra da Silva; Pedro Henrique Dias Batista; Rodes Angelo Batista da Silva; Pabricio Marcos Oliveira Lopes; Diego Castro da Silva
The objective of this work was to characterize the spectral responses of soil and plant indicators utilizing the Soil-Adjusted Vegetation Index (SAVI) and Leaf Area Index (LAI) in areas under the cultivation of ‘Orelha de Elefante Mexicana’ forage cactus (Opuntia stricta (Haw.) Haw.) and ‘Miúda’ (Nopalea cochenillifera (L.) Salm-Dyck) in Brazilian semi-arid region and to establish a model for characterizing
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Recent sedimentation in an Amazon tidal tributary: Integrated analysis of morphology and sedimentology J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-31 Ariane M.M. Silva; Nils E. Asp; Vando J.C. Gomes; Antonia A. Braga; José D. Gomes; Aaron T. Fricke; Pedro Walfir M. Souza-Filho; Thiago P. Souza; Pryscilla D. Almeida; Andrea S. Ogston; Charles A. Nittrouer
The Xingu River is an important tributary of the Amazon River, contributing 5% of its total water discharge. Nevertheless, it does not contribute substantially to the sediment load. The lower reach of the Xingu River forms a ria, a result of the Holocene sea-level rise. The Xingu is also classified as a tidal river, with tides >1 m at its confluence with the Amazon River. This study evaluated the morphology
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Evaluation of geomorphological approaches combined with digital elevation models for the Nash's instantaneous unit hydrograph J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-12 Maíra Martim de Moura; Samuel Beskow; Fabrício da Silva Terra; Carlos Rogério de Mello; Zandra Almeida da Cunha; Felício Cassalho
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Triassic sauropodomorph dinosaurs from South America: The origin and diversification of dinosaur dominated herbivorous faunas J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-11 Diego Pol; Alejandro Otero; Cecilia A. Apaldetti; Ricardo J. Martínez
Sauropodomorpha is the first major dinosaurian group that radiated during the Triassic. During this time the group underwent major changes in body plan, including the acquisition of features related to herbivory, large body size, and quadrupedality. By the end of the Late Triassic, approximately 30 million years after the origin of dinosaurs, sauropodomorphs predominated the niches of large herbivores
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An assessment of the wealth of information given by sponge spicules as a paleoenvironmental tool: The case of two lakes in northeast (Brazil) J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-14 Loyana Docio; Giliane Gessica Rasbold; André Luiz Carvalho da Silva; Mauro Parolin; Marcelo Galeazzi Caxambu; Ulisses Pinheiro
This study aimed to test the use of inland sponge spicules as proxy data for a Holocene paleoenvironmental reconstruction of the Trairí River valley, in the state of Rio Grande do Norte, in Northeast Brazil. Spicules were recovered from sediments from two core samples obtained from Lake Fumo and Lake Urtiga, at depths of 0.60 m and 0.96 m, respectively. The following analyses were carried out: phytolith
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Upper Triassic hemipterans from the south-western Gondwana: taxonomical, paleobiological, and paleogeographical implications J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 María B. Lara; Evelyn L. Bustos-Escalona; Adriana C. Mancuso; Andrea Arcucci
Two new hemipteran taxa are described: Dysmorphoptiloides losrastrosensis sp. nov. and Gualoscarta obscura gen. et sp. nov. (Auchenorryncha: Dysmorphoptilidae). Likewise, we report the first specimen of a corixid (Heteroptera: Nepomorpha) from the Triassic of Gondwana. The fossil material studied in this paper comes from the Gualo locality, the Carnian Los Rastros Formation, Ischigualasto-Villa Unión
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Procedures of engineering geological mapping applied to urban planning in a data-scarce area: Application in southern Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-31 Iraydes Tálita de Sena Nola; Lázaro Valentim Zuquette
Results from an engineering geological mapping study of the urban area of Ouro Preto in the state of Minas Gerais, Brazil, are presented. The goal of the study was to verify the efficacy of procedures, methods and classification schemes based on engineering geological mapping principles to generate data and maps for urban planning, restructuring (rehabilitation) and engineering projects. The study
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Late Cretaceous palynomorphs from the Golfo San Jorge Basin, Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-04 V.S. Perez Loinaze; S.R. Giordano; C.O. Limarino
A lithofacial and palynological study was carried out on the Cañadón Seco Formation in the La Frieda Oeste x-1 well (Golfo San Jorge Basin). According to sedimentological characteristics of the core four main litofacies lithofacies are defined: 1. Cross-bedded sandstones, 2. Interlaminated fine-grained sandstones and mudstones, 3. Shales, and 4. Muddy tuff. The cross-bedded sandstones correspond to
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Integrated hazards maps of the Tacaná Volcanic complex, Mexico-Guatemala: Ashfall, block-and-ash flows, and lahars J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-05 Rosario Vázquez; José Luis Macías; José Luis Arce
The Tacaná Volcanic Complex (TVC) is an active volcano, located on the border between Mexico and Guatemala, in the westernmost part of the Central American Volcanic Arc. The TVC has produced effusive and explosive activity during the past 300 ka through the emplacement of lava flows, pyroclastic deposits, debris avalanches and lahars. During the last 10 ka, at least 11 eruptions have occurred, with
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The carboniferous onset of subduction at SW Gondwana revisited: Sedimentation and deformation processes along the late Paleozoic forearc of north Chile (21°–33° S) J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-05 Christian Creixell; Fernando Sepúlveda; Javier Álvarez; Paulina Vásquez; Ricardo Velásquez
The geological record of late Paleozoic rocks is ubiquitous along the north to central Chile (21°–33° S). The most accepted evolutionary model proposes that the SW-Gondwana margin in northern Chile (north of 28° S) evolved from a passive margin setting in the Devonian to late Carboniferous that switched to an active margin setting during the early to late Carboniferous and continued during the Permian
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Late Paleozoic basins of South America: Insights and progress in the last decade J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-07 Carlos O. Limarino; Oscar R. López-Gamundí
This paper presents a synthesis of the advances in the geologic knowledge of the late Paleozoic basins of southern South America during the last decade. The information is focused on: i) progress in paleogeographic models and new perspectives, ii) distribution of late Paleozoic glacial deposits, sedimentary models and identification of discrete events, iii) paleoclimatic evolution and pieces of evidence
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The Sierra de Aguirre Formation, Uruguay: Post-collisional Ediacaran volcanism in the southernmost Dom Feliciano Belt J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-29 Hernán Silva Lara; Siegfried Siegesmund; Klaus Wemmer; Mathias Hueck; Miguel A.S. Basei; Pedro Oyhantçabal
The Sierra de Aguirre Fm. in southern Uruguay constitutes one of several post-collisional basins of the Dom Feliciano Belt, preserving an important volcanic record associated with this protracted stage of the orogenic system. This study combines new stratigraphic, structural, geochronological and isotopic geochemical results, together with a reassessment of the available geochemical data, to present
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Provenance of metasedimentary rocks of the western Dom Feliciano Belt in Uruguay: Insights from U–Pb detrital zircon geochronology, Hf and Nd model ages, and geochemical data J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-08 P. Oyhantçabal; S. Oriolo; K. Wemmer; M.A.S. Basei; D. Frei; S. Siegesmund
New isotopic and geochemical data for the Paleo- Meso- and Neoproterozoic metasedimentary cover of the southern Dom Feliciano Belt (Brasiliano/Pan-African) are presented and evaluated combined with published information. Whole-rock major and trace element geochemistry indicates that the dominant source for all the units was the upper continental crust. The geochemistry is similar even for late Ediacaran
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Geology, petrogenesis, and geochronology of the Rio Salitre Complex: Implications for the Paleoproterozoic evolution of the northern São Francisco Craton, Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-06 Pedro Maciel de Paula Garcia; Eduardo Luiz Vieira Carrilho; Bruno Pinto Ribeiro; Aroldo Misi; José Haroldo da Silva Sá; Débora Correia Rios
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Lithofaciological analysis of the exposed rocks of the Itapecuru Formation, northeastern Parnaíba Basin, Brazil: paleoenvironmental implications J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 Neila N. Ferreira; Renato R.C. Ramos; Elizabete P. Ferreira; Ismar de S. Carvalho
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Anisotropy of magnetic susceptibility analysis in Tunas Formation cores (Permian), Claromecó Basin, Buenos Aires, Argentina: Its relation to depositional and post-depositional conditions J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-02 María Belén Febbo; Renata N. Tomezzoli; Juan M. Calvagno; Guadalupe Arzadún; Leandro C. Gallo; Nora N. Cesaretti
Anisotropy of magnetic susceptibility (AMS) has been used as an important tool to study magnetic fabrics and as a basis of interpretation of depositional conditions and post-depositional processes in sedimentary successions. This contribution presents results of standard AMS and magnetic mineralogy analysis performed in core samples from the PANG 0003 well, located at the Claromecó Basin, Buenos Aires
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Bioerosion on marine Quaternary gastropods from the southern Golfo San Jorge, Patagonia, Argentina: What do they tell US? J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 Sebastian Richiano; Marina L. Aguirre; Luciana Giachetti
We present the ichnological characterization on marine gastropod shells from Late Pleistocene, mid-Holocene and modern beaches at 5 sampling sectors along the southern Golfo San Jorge, a key area at central Patagonia in terms of geological, physical and biological features of the southern Southwestern Atlantic margin. Based on bioerosion recovered in 579 gastropod shells (22% showing bioerosion and
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New record of Late Cretaceous vertebrate tracks from the Yacoraite Formation (Juella, Quebrada de Humahuaca, northwestern Argentina): aerial drone survey, preservation and sedimentary context J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-07 Carlos Cónsole-Gonella; Ignacio Díaz-Martínez; Paolo Citton; Silvina de Valais
The Yacoraite Formation is a worldwide known unit due to the diversity and abundance of vertebrate ichnological record. The complex tectono-sedimentary evolution related to the Andean Cycle generated high dip angles of bedding and, consequently, large tracksites are not easily accessible, making hard the ichnological analysis. Here, we describe a new tracksite named “La Banderita”, near Juella town
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Multi-proxy case study of a Neoproterozoic rhyolite flow in southernmost Brazil: Emplacement mechanisms and implications for ancient felsic lavas J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-11-12 Maurício Barcelos Haag; Rayane Bastos de Freitas; Carlos Augusto Sommer; Jairo Francisco Savian; Evandro Fernandes Lima; Johnathan Henrique Gambeta; Diego da Silveira Lyra; Ricardo Ivan Ferreira da Trindade
Rhyolites compose an important record in the volcanic history of Earth, with significant occurrences in volcanic arcs, large igneous provinces and post-collisional terranes, often associated with explosive events. In several geologic provinces, rhyolites dominate as the most expressive geologic units (e.g., Silicic Large Igneous Provinces - SLIPs). Despite their importance, several aspects related
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First paleoseismological results in the epicentral area of the sixteenth century Ameca earthquake, Jalisco – México J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-30 Andrés Núñez Meneses; Pierre Lacan; F. Ramón Zúñiga; Laurence Audin; María Ortuño; José Rosas Elguera; Rodrigo León-Loya; Víctor Márquez
The Trans-Mexican Volcanic Belt (TMVB) is a calc-alkaline volcanic arc cut by different active crustal fault systems that have originated several destructive historical earthquakes. Located in the central part of Mexico this region offers exceptional climatic, and fertility of soil conditions, which is the reason why more than 50% of the Mexican population now live here, increasing the seismic risk
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U–Pb geochronology and Lu–Hf zircon isotopy of the Santinho Granitic Association: A remnant of the early magmatic stages of the Florianópolis Batholith, Santa Catarina, Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-07 Miguel A.S. Basei; Vinícius X. Corrêa; Neivaldo A. Castro; Mathias Hueck
One of the main characteristics of the orogenic systems formed during the assembly of southwestern Gondwana in the Late Neoproterozoic is the widespread granitic magmatism. The Florianópolis Batholith in South Brazil is an excellent example of this process, as it is part of a ca. 1,400 km long intrusive association that is a key unit in the reconstruction of the paleogeography of Gondwana on both sides
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Structural architecture and the episodic evolution of the ediacaran Campo Alegre Basin (southern Brazil): Implications for the development of a synorogenic foreland rift and a post-collisional caldera volcano J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-06 Lucas Martins Lino; Francy Roxana Quiroz-Valle; Vinicius Louro; Miguel Ângelo Stipp Basei; Silvio Roberto Farias Vlach; Mathias Hueck; Patricio Rodrigo Montecinos Munõz; Sérgio Brandolise Citroni
During the last decades, tectonic models provided new insight into the evolution of the Luis Alves, Curitiba, and Paranaguá terranes, which are all limited by thrust and transpressive shear zones, nowadays outcropping only as deep crustal horizons and presenting poorly known lateral displacements. An essential puzzle piece to understanding the juxtaposition processes and evolution of these blocks in
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The genera Heidiphyllum and Dordrechtites, and associated fossil wood from the Triassic Ischichuca Formation, northwestern Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2021-01-04 Marisol Beltrán; Josefina Bodnar; Ricardo Melchor
New fossil plants are described from the Ischichuca Formation (Middle?–Late Triassic), La Rioja province, northwestern Argentina. A systematic description of Heidiphyllum leaves, ovulate structures of Dordrechtites and undetermined conifer wood is provided. This is the first description of these elements for the Ischichuca Formation, and the first illustration of Dordrechtites from South America, thus
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Geomorphology and sedimentary processes on the Sloggett Canyon, Northwestern Scotia Sea, Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-30 F.I. Palma; G. Bozzano; S. Principi; J.I. Isola; J.P. Ormazabal; F.D. Esteban; A.A. Tassone
The southern Argentine Continental Margin hosts the Tierra del Fuego Submarine Canyon System, located in the northwestern Scotia Sea, and formed by 4 main canyons: Valentín, Sloggett, Nueva Canyon, and Wollaston. This region is especially interesting due to its complex tectonic setting and its proximity to the polar regions where intense bottom currents associated with the Argentine Contourite Depositional
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Advanced signal recognition methods applied to seismo-volcanic events from Planchon Peteroa Volcanic Complex: Deep Neural Network classifier J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 Verónica L. Martínez; Manuel Titos; Carmen Benítez; Gabriela Badi; José Augusto Casas; Victoria H. Olivera Craig; Jesús M. Ibáñez
Advanced techniques in the recognition and classification of seismo-volcanic events are transcendental when studying active volcanoes, not only for their importance as an accurate real time seismic monitoring procedure but also for the use of their results in modeling the dynamics of the volcanic environment. It is well known that real time seismic monitoring deals with such a large amount of data
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Evidences of an unknown debris avalanche event (<0.58 Ma), in the active azufral volcano (Nariño, Colombia) J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-31 Catalina Moreno-Alfonso; John Jairo Sánchez-Aguilar; Hugo Murcia
Azufral volcano is an active composite volcano located in SW Colombia, whose edifice is mostly formed by pyroclastic deposits and lava flows. Recent road works in the region, NE of the volcano, revealed unknown deposits, one of them related to a debris avalanche event. This deposit, herein named San Roque debris avalanche deposit, outcrops along a 13 km section in the road Túquerres - Samaniego. Using
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Geochemical constraints on the origin and distribution of Cretaceous source rocks in the Ceará basin, Brazilian Equatorial margin J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 Ana Clara B. de Souza; Daniel R. do Nascimento; Alessandro Batezelli; Francisco Nepomuceno Filho; Karen M. Leopoldino Oliveira; Narelle Maia de Almeida; Márcio N. Normando; Thiago H. da Silva Barbosa
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Filamentous cyanobacteria and associated microorganisms, structurally preserved in a Late Jurassic chert from Patagonia, Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-25 J.L. Garcia Massini; D.M. Guido; K.C. Campbell; A.J. Sagasti; M. Krings
A new cyanobacterium, Patagonifilum jurassicum nov. gen. et sp., is structurally preserved in Late Jurassic hydrothermally influenced siliceous chert from the Deseado Massif, Patagonia, Argentina. The cyanobacterium occurs in the form of loosely to densely spaced, heteropolar filaments (up to 4.5 μm wide) that form turf-like stands, or spherical to hemispherical colonies on different substrates, usually
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Reconstruction of the effusive and explosive deposits of the Aruri and Salustiano formations in the Tapajós Domain, Southern Amazonian Craton, from field relationship, petrography and geochemistry J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-15 André Massanobu Ueno Kunifoshita; Felipe Holanda dos Santos; João Gabriel Motta
Proterozoic Silicic Large Igneous Provinces (SLIP) are part of the geological inventory since they record the planet's thermal evolution. The Amazonian Craton hosted the poorly understood Uatumã SLIP, which formed ca. 1.88 Ga years ago. The so-called Uatumã magmatism represents the volcanic products of SLIP. This magmatism also refers to specific stratigraphic units, such as the Uatumã, Iriri, and
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Bioerosive traces in a Pleistocene Anatid bone from Uruguay J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-23 Carolina Acosta Hospitaleche; Washington Jones; Andrés Rinderknecht
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Synkinematic interplay between felsic dykes and host rock mylonitization: how magmatism assists the formation of ductile narrow shear zones in the Sierra Chica de Córdoba, Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-09 M. Alejandra Boffadossi; Jorge E. Coniglio; M. Natalia Maffini; Lucio P. Pinotti; Stefania Radice; Fernando J. D'Eramo; Manuel Demartis; M. Eugenia Muratori; Joaquín Coniglio
This study provides new insights about mechanisms of synkinematic interplay between dyking emplacement and ductile narrow shear zones formation in the Sierra Chica de Córdoba. A detailed analysis of structural, microstructural, geometric-scaling and geochronologic data is performed in order to demonstrate the important role that minor and meso-scale felsic dykes played in the formation of paired shear
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Pululahua dome complex, Ecuador: eruptive history, total magma output and potential hazards J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-03 S. Daniel Andrade; Anais Vásconez Müller; Francisco J. Vasconez; Bernardo Beate; Jorge Aguilar; Santiago Santamaría
Pululahua is a potentially active dome complex located 15 km north of Quito. It is composed of sixteen dacitic-andesitic lava domes located inside and around a semi-rectangular depression. We divide its eruptive history into: (1) a first member characterized by effusive lava dome growth and collapse (Units I and II, >18–12 ka), (2) a second member consisting of at least four explosive eruptive phases
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A reply to Fossen et al. (2020) comment to “Neoproterozoic magmatic arc systems of the central Ribeira belt, SE-Brazil, in the context of the West-Gondwana pre-collisional history: A review” J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-24 Monica Heilbron; Claudio de Morisson Valeriano; Caroline Peixoto; Miguel Tupinambá; Franz Neubauer; Ivo Dussin; Felipe Corrales; Henrique Bruno; Marcela Lobato; Julio Cesar Horta de Almeida; Luiz Guilherme do Eirado Silva
The scope of the original manuscript of Heilbron et al. (2020) was to present a geological, geochemical, isotopic, petrologic and geochronological synthesis regarding the Neoproterozoic (850–530 Ma) Ribeira orogenic belt. The magmatic arc-related associations of this orogenic belt were developed during the amalgamation of West Gondwana and display accretionary and collisional magmatic arc signatures
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Exposing the inside of the fine-grained siliciclastic tidal shelf deposits of the Alicia Formation, Tandilia Basin, during the Ediacaran anoxia in the Clymene Ocean J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-11-19 M. Julia Arrouy; Lucía E. Gómez-Peral
In this contribution we outline the outstanding attributes and inferred depositional controls for dark mudstones of the Alicia Formation (~570 Ma) in order to reveal the intrinsic characteristics of unknown Ediacaran marine depositional conditions into the basin. The Alicia Formation represents a continuous and undeformed ~150 m thick sequence in which nine siliciclastic lithofacies were accumulated
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Timing and rates of morpho-tectonic events in a segment of the Central and Western cordilleras of Colombia revealed through low-temperature thermochronology J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-18 S. Duque-Palacio; D. Seward; S.A. Restrepo-Moreno; D. García-Ramos
New zircon and apatite fission-track analyses and aluminium in hornblende thermobarometric data are presented from Cretaceous and Triassic plutons situated along an east-west transect across the Central Cordillera, the Cauca Romeral Fault System and the eastern slopes of the Western Cordillera in the Colombian Andes. The results are combined with published apatite (U–Th)/He ages revealing three episodes
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New invertebrate peri-glacial faunal assemblages in the Agua de Lucho Formation, Río Blanco Basin, Argentina. The most complete marine fossil record of the early Mississippian in South America J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-10 A.F. Sterren; G.A. Cisterna; J.J. Rustán; N.E. Vaccari; D. Balseiro; M. Ezpeleta; C. Prestianni
A new fossil record of early Mississippian marine faunas is described from the Agua de Lucho Formation in the Sierra de las Minitas (La Rioja province, Río Blanco Basin, western Argentina). Considered Tournaisian in age based on local palynological data and biostratigraphic correlations, this faunal record is notably diverse associated with glacially influenced deposits, in contrast with other early
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The glacial paleovalley of Vichigasta: Paleogeomorphological and sedimentological evidence for a large continental ice-sheet for the mid-Carboniferous over central Argentina J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-08 Victoria Valdez Buso; Juan Pablo Milana; Mercedes di Pasquo; José Espinoza Aburto
We present new data on the Vichigasta Carboniferous paleovalley, a glacial trough crucial to understand the type of glaciation that affected western Gondwana during the Late Paleozoic Ice Age (LPIA). The filling of this paleovalley starts soon after the mid-Carboniferous glacial peak. Stage I represents pro-glacial lacustrine deposits with outwash, glacially rafted dropstones, mass transport deposits
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Taphonomy of a skeleton of Arctocephalus australis (Carnivora: Pinnipeda: Otariidae) from the Holocene of Miramar locality (southern Buenos Aires, Argentina) J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-09 Cristian A. Pereyra; Mariano Magnussen
The taphonomy of a partial skeleton of the fur seal Arctocephalus australis from the mid-Holocene of Miramar (southern Buenos Aires province, Argentina) comprising most of both hindlimbs and some vertebral elements is herein described and discussed. The main axis of the long bones is oriented perpendicular to the coastline, flexed and slightly disarticulated, while the vertebrae are somewhat arched
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Martin Vaz island geochronology: Constraint on the Trindade Mantle Plume track from the youngest and easternmost volcanic episodes J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-16 Anderson Costa dos Santos; João Mata; Fred Jourdan; Sérgio Willians de Oliveira Rodrigues; Lucas Guimarães Pereira Monteiro; Eliane Guedes; Leonardo Benedini; Mauro César Geraldes
The oceanic basins are dotted by seamounts, guyots and islands formed by the mantle plumes and oceanic lithosphere interaction. These plumes are responsible for several intraplate volcanisms such as the Emperor-Hawaii Chain in the Pacific Ocean with a remarkable bend at ca. 47 Ma. Comparatively, the Vitória-Trindade Ridge (VTR) in the South Atlantic Ocean was also generated by a mantle plume and in
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Early cretaceous Brachyoxylon woods from Argentinean Patagonia and comments on the Cheirolepidiaceae distribution J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-11-25 Carlos D. Greppi; Roberto R. Pujana; Aldo M. Umazano; Eduardo S. Bellosi
We studied fossil woods from Matasiete and Castillo Formations (Aptian–Albian) for the first time. The woods, preserved in fluvial channel and floodplain deposits, have anatomy consistent with the fossil-genus Brachyoxylon Hollick and Jeffrey. Specimens from Castillo Formation have poorly distinct growth ring boundaries, exclusively uniseriate with a mixed arrangement intertracheary radial pitting
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Population dynamics of Equus conversidens (Perissodactyla, Equidae) from the late Pleistocene of Hidalgo (central Mexico): Comparison with extant and fossil equid populations J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-14 Alexis Pérez-Pérez; Victor Manuel Bravo-Cuevas; Philippe Fernandez
The Mexican horse Equus conversidens is a representative member of the Quaternary North American megafauna. Systematics, phylogeny, and stable isotope ecology of this species are known in some detail, although information regarding population ecology is unexplored. Numerous fossil remains (isolated teeth, mandibles, skulls, and postcranial elements) of this horse have been collected from Pleistocene
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Advances in geochemical footprint, iron speciation, and Pb isotopes in the tropical regolith of north-northwestern Amazonia, Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-12-11 Adriana Maria Coimbra Horbe; Márcio Fernando dos Santos Albuquerque; Rodrigo Tokuta Castro; Sanclever Freire Peixoto
A dataset with information on samples of gabbro, charnockite, gneiss, granite, basalt, and sandstone-derived iron lateritic duricrusts, concretions, nodules, and soils was analyzed to address the multi-element chemical composition, background values, scavenger trace elements in Fe oxyhydroxides, parent rock inheritance, and weathering effect on Pb isotopes. Tropical weathering causes high mass loss
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Early Cambrian multiple-sourced plutonism in the Eastern Sierras Pampeanas, Córdoba, Argentina: Implications for the evolution of the early Paleozoic Gondwana margin J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-11-25 Alina M. Tibaldi; Juan E. Otamendi; Alejandro H. Demichelis; Matías G. Barzola; Fernando Barra; Osvaldo M. Rabbia; Eber A. Cristofolini; María P. Benito
Four major igneous suites with different geochemical characteristics are identified in the accretionary complex of the Pampean orogeny from the southern Sierras de Córdoba, Argentina. Crystallization ages of gabbroic and trondhjemitic plutonic rocks are Early to Middle Cambrian. The plutonic suites include mafic to intermediate alkaline OIB-like rocks, mafic tholeiitic N-MORB rocks, transitional mafic
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South Atlantic passive margin evolution: A thermochronology case study from the Rio de Janeiro-Três Rios section, SE Brazil J. South Am. Earth Sci. (IF 1.704) Pub Date : 2020-11-24 J.N. Gezatt; D.I.M. Macdonald; R. Stephenson; A.R. Jelinek; A. Carter
The southeastern Brazilian passive margin records a complex post-rift evolution, with two parallel high-elevation features formed after the opening of the South Atlantic. We applied apatite fission track (AFT) and U–Th/He (AHe) low temperature thermochronology to constrain the thermo-tectonic history of the Serra do Mar escarpment in the area of Rio de Janeiro state. New AFT central ages for basement