Academic literature on the topic 'Nannofossiles – Neuquén, Bassin de (Argentine)'

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Journal articles on the topic "Nannofossiles – Neuquén, Bassin de (Argentine)"

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Hunnig Bom, Marlone H., Rodrigo do Monte Guerra, Andrea Concheyro, and Gerson Fauth. "Methodologies for recovering calcareous nannofossils from bituminous claystone." Micropaleontology 61, no. 3 (2015): 165–70. http://dx.doi.org/10.47894/mpal.61.3.02.

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The usual methods applied to recover calcareous nannofossils from claystones are extremely simple, cost-effective and fast. Some samples, however, exhibit heterogeneous mixtures of biogenic materials, detrital particles and other aggregates that visually mask the coccoliths under the microscope. For instance, a high content of organic matter in associationwith calcareous nannofossil specimens was observed in outcrop samples of the Vaca Muerta Formation (Neuquén Basin, Argentina). To solve this problem, traditional preparation techniques are herein improved to aid better visualization of calcareous nannofossils. Sixteen tests were qualitatively and quantitatively evaluated, testing the efficiency of some chemicals and physicals methods such as the addition of a solvent (oxidizing agent) in the smear slide technique, as well as the use of ultrasound in the random decantation technique.
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Chaumeil Rodríguez, Micaela, Emanuela Mattioli, and Juan Pablo Pérez Panera. "Lower Jurassic calcareous nannofossil taxonomy revisited according to the Neuquén Basin (Argentina) record." Journal of Micropalaeontology 41, no. 1 (April 26, 2022): 75–105. http://dx.doi.org/10.5194/jm-41-75-2022.

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Abstract. Standard Early Jurassic biostratigraphic studies were performed in the boreal and Tethys realms (western Europe and northern Africa), and biozonations from these areas are the most accurate of the world. Comparatively, investigations in the Pacific realm are scarce, and, in Argentina, they are limited to contributions based on oil-industry subsurface and outcrop reports for the Los Molles Formation. A focused systematic analysis was not previously addressed in the area. The Neuquén Basin in west–central Argentina offers a unique opportunity to study the Early Jurassic calcareous nannofossil history in the south-eastern Pacific Ocean. Calcareous nannofossil assemblages from El Matuasto I section (Los Molles Formation) represent one of the earliest records for the Early Jurassic in the Neuquén Basin and one of the few for the eastern Pacific realm. A detailed systematic analysis allowed the recognition of major bioevents and a comparison with worldwide associations and biostratigraphic schemes. A thorough taxonomic discussion of the Early Jurassic nannofossil species of the Neuquén Basin is presented for the first time. Herein, the taxonomic features of coccoliths recorded in the Neuquén Basin are settled. The age of the calcareous nannofossil assemblages recorded in El Matuasto I is early–late Pliensbachian, covering the NJT4a to NJT4c subzones. Similarities between the Neuquén Basin and localities from the proto-Atlantic region suggest an effective connection between the Pacific and Tethyan basins during the Pliensbachian.
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Chaumeil Rodríguez, Micaela, Emanuela Mattioli, and Juan Pablo Pérez Panera. "Lower Jurassic calcareous nannofossil taxonomy revisited according to the Neuquén Basin (Argentina) record." Journal of Micropalaeontology 41, no. 1 (April 26, 2022): 75–105. http://dx.doi.org/10.5194/jm-41-75-2022.

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Abstract. Standard Early Jurassic biostratigraphic studies were performed in the boreal and Tethys realms (western Europe and northern Africa), and biozonations from these areas are the most accurate of the world. Comparatively, investigations in the Pacific realm are scarce, and, in Argentina, they are limited to contributions based on oil-industry subsurface and outcrop reports for the Los Molles Formation. A focused systematic analysis was not previously addressed in the area. The Neuquén Basin in west–central Argentina offers a unique opportunity to study the Early Jurassic calcareous nannofossil history in the south-eastern Pacific Ocean. Calcareous nannofossil assemblages from El Matuasto I section (Los Molles Formation) represent one of the earliest records for the Early Jurassic in the Neuquén Basin and one of the few for the eastern Pacific realm. A detailed systematic analysis allowed the recognition of major bioevents and a comparison with worldwide associations and biostratigraphic schemes. A thorough taxonomic discussion of the Early Jurassic nannofossil species of the Neuquén Basin is presented for the first time. Herein, the taxonomic features of coccoliths recorded in the Neuquén Basin are settled. The age of the calcareous nannofossil assemblages recorded in El Matuasto I is early–late Pliensbachian, covering the NJT4a to NJT4c subzones. Similarities between the Neuquén Basin and localities from the proto-Atlantic region suggest an effective connection between the Pacific and Tethyan basins during the Pliensbachian.
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Bown, P. R., and C. Ellison. "Jurassic-Early Cretaceous nannofossils from the Neuquén Basin, Argentina." Journal of Nannoplankton Research 17, no. 2 (1995): 48. http://dx.doi.org/10.58998/jnr2024.

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Ballent, Sara, Andrea Concheyro, and Guillermina Sagasti. "Biostratigraphy and palaeoenvironment of the Agrio Formation (Lower Cretaceous), Mendoza Province, Neuquén Basin, Argentina." Andean Geology 33, no. 1 (June 30, 2010): 47. http://dx.doi.org/10.5027/andgeov33n1-a03.

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A bioestratigraphical and palaeoenvironmental study of the Agrio Formation, at the Cuesta del Chihuido section, southern Mendoza Province (35º45'S/69º34'W), Argentina, is presented. Thirty seven species of nannofossils, thirty four of foraminifers and six of ostracods have been recognized. Nannofossils association corresponding to Zones CC4A y CC4B indicates an Upper Valanginian-Upper Hauterivian age. At the base of the section, the presence of the benthonic foraminifer Epistomina loncochensis Ballent and radiolaria suggests eutrophic conditions of surface waters and oxygen depressed sea-bottom conditions. In the middle part of the section, diversity of lagenid foraminifers and nannofossils indicates a shelf and nearshore environment with clear and well-oxygenated waters. Abundant polymorphinids, spirillinids and involitinids towards the top of the section corroborate a general regressive tendency. Mudstones and silty-sandstone intercalations containing allochthonous adherent foraminifers and adult carapaces of cytheroid ostracods represent distal storm deposits.
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Scott, Robert W. "Tithonian-Hauterivian chronostratigraphy (latest Jurassic-Early Cretaceous), Mediterranean-Caucasian Subrealm and southern Andes: A stratigraphic experiment and Time Scale." Carnets de géologie (Notebooks on geology) 22, no. 13 (August 1, 2022): 619–60. http://dx.doi.org/10.2110/carnets.2022.2213.

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New radioisotopic dates of Tithonian-Hauterivian strata in the Neuquén Basin significantly recalibrate Early Cretaceous numerical ages. In order to evaluate the implications of these revised ages, a graphic correlation experiment of twenty-three Andean Tithonian to Hauterivian sections integrated the ranges of 254 species, sequence boundaries, polarity chrons, and radioisotopic ages that compose the ANDESCS DB. This database accurately reproduces the order of Andean ammonite zones and places them in a relative metric scale of a composite reference section. The ranges in the ANDESCS DB were correlated with the LOK2016 DB that comprises Tithonian-Albian ammonites, calpionellids, nannofossils, and polarity chrons in Mediterranean-Caucasian Subrealm stage reference sections. In 2017 these ranges were calibrated to GTS2016 mega-annums (MA). Although most Andean ammonoids were endemic to the Indo-Pacific Subrealm, nannofossils, calpionellids and polarity chrons were present in both areas. This stratigraphic experiment correlates base Berriasian as defined in France within the Substeueroceras koeneni Zone. In Andean sections this boundary is correlated with the Crassicolaria/Calpionella zone boundary dated at about 141 Ma. The base of the Valanginian defined by Calpionellites darderi correlates with the Neocomites wichmanni Zone of the Neuquén Basin (NB) recalibrated at 139.50 Ma, which is confirmed by multiple dates in Argentina, Mexico, Tibet, and elsewhere. The base Hauterivian correlates with base of Holcoptychites neuquensis Zone in the NB recalibrated at 131 Ma. Top of Hauterivian is in the Sabaudiella riverorum Zone in the NB and is dated at 127 Ma below an unconformity. Previous cyclostratigraphic astrochronologic cycles are averaged and calibrate the duration of the Tithonian at 5.67 myr, the Berriasian at 5.27 myr, the Valanginian at 5.30 myr, and the Hauterivian at 5.60 myr. The age of each stage is recalibrated by adding revised durations to the most common age of base Valanginian of 139.5 Ma. These ages revise the Berriasian to Hauterivian stages time scale, and the ages of stage boundaries are on average 2.8 myr longer than proposed by the new Neuquén Basin radioisotopic dates.
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Aguirre-Urreta, M. B., A. Concheyro, M. Lorenzo, E. G. Ottone, and P. F. Rawson. "Advances in the biostratigraphy of the Agrio Formation (Lower Cretaceous) of the Neuquén Basin, Argentina: ammonites, palynomorphs, and calcareous nannofossils." Palaeogeography, Palaeoclimatology, Palaeoecology 150, no. 1-2 (June 1999): 33–47. http://dx.doi.org/10.1016/s0031-0182(99)00006-1.

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Lescano, Marina, Andrea Caramés, Andrea Concheyro, Cecilia Cataldo, Darío G. Lazo, Leticia Luci, and Beatriz Aguirre-Urreta. "Early Cretaceous calcareous nannofossils and foraminifera from the Huitrín Formation (La Tosca Member), Neuquén Basin, Argentina, and their biostratigraphic and paleoecological implications." Journal of South American Earth Sciences 112 (December 2021): 103538. http://dx.doi.org/10.1016/j.jsames.2021.103538.

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CaramÉs, Andrea, Mariano Martinez, Andrea Concheyro, Mariano RemÍrez, and Susana Adamonis. "Holothuroidea: new records from the Lower Cretaceous of the Agrio Formation, Neuquén Basin, Argentina. An integrated study with foraminifers and calcareous nannofossils." Alcheringa: An Australasian Journal of Palaeontology 43, no. 4 (August 5, 2019): 580–96. http://dx.doi.org/10.1080/03115518.2019.1641617.

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Al-Suwaidi, Aisha H., Micha Ruhl, Hugh C. Jenkyns, Susana E. Damborenea, Miguel O. Manceñido, Daniel J. Condon, Gladys N. Angelozzi, et al. "New age constraints on the Lower Jurassic Pliensbachian–Toarcian Boundary at Chacay Melehue (Neuquén Basin, Argentina)." Scientific Reports 12, no. 1 (March 23, 2022). http://dx.doi.org/10.1038/s41598-022-07886-x.

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AbstractThe Pliensbachian–Toarcian boundary interval is characterized by a ~ 3‰ negative carbon-isotope excursion (CIE) in organic and inorganic marine and terrestrial archives from sections in Europe, such as Peniche (Portugal) and Hawsker Bottoms, Yorkshire (UK). A new high-resolution organic-carbon isotope record, illustrating the same chemostratigraphic feature, is presented from the Southern Hemisphere Arroyo Chacay Melehue section, Chos Malal, Argentina, corroborating the global significance of this disturbance to the carbon cycle. The negative carbon-isotope excursion, mercury and organic-matter enrichment are accompanied by high-resolution ammonite and nannofossil biostratigraphy together with U–Pb CA-ID-TIMS geochronology derived from intercalated volcanic ash beds. A new age of ~ 183.73 + 0.35/− 0.50 Ma for the Pliensbachian–Toarcian boundary, and 182.77 + 0.11/− 0.15 for the tenuicostatum–serpentinum zonal boundary, is assigned based on high-precision U–Pb zircon geochronology and a Bayesian Markov chain Monte Carlo (MCMC) stratigraphic age model.
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Dissertations / Theses on the topic "Nannofossiles – Neuquén, Bassin de (Argentine)"

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Chaumeil, Rodriguez Micaela. "Calcareous nannofossils from Los Molles Formation, south of Huincul High, Neuquén Basin, Argentina : biostratigraphy and paleobiogeographic reconstructions for the Early to Middle Jurassic (Pliensbachian-Aalenian)." Electronic Thesis or Diss., Lyon 1, 2023. http://www.theses.fr/2023LYO10116.

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Les nannofossiles calcaires représentent un groupe diversifié de fossiles, remontant au Trias supérieur et s'étendant jusqu'à nos jours, caractérisés par leur composition calcaire et une taille inférieure à 30 µm. Parmi eux, les coccolithophoridés, qui constituent la fraction la plus importante du nannoplancton calcaire, c'est-à-dire des algues unicellulaires flagellées typiquement marins appartenant à la sous-classe Calcihaptophycidae, recouvertes de plaques de carbonate de calcium (coccolithes). Les représentants fossiles des coccolithophoridés correspond à leurs restes d'exosquelette, généralement conservés sous une forme désagrégée, comme des coccolithes individuels. Leur présence dans les océans est essentielle, car ils constituent l'un des principaux groupes de producteurs primaires marins. Les données géologiques suggèrent que les coccolithophoridés ont maintenu leurs exigences écologiques presque inchangées au fil du temps, et ainsi nous permettant de reconstruire de manière fiable les conditions paléoenvironnementales, paléobiogéographiques et paléoclimatiques. L'objectif général de cette thèse est d'étudier les associations de nannofossiles calcaires des sédiments marins du Jurassique inférieur-moyen au sud haut structural de Huincul du bassin de Neuquén (Argentine) et de combiner ces informations avec celles déjà disponibles afin d'élargir et d'améliorer les ressources biostratigraphiques du bassin. En comparant ces enregistrements avec des associations de nannofossiles calcaires provenant d'autres endroits du monde, nous visons à établir des corrélations d'âge globales et à évaluer les relations paléobiogéographiques, afin de générer un modèle biostratigraphique local. L'étude se concentre sur des échantillons provenant de trois sections d'affleurement et de deux forages d'exploration. Un total de 102 échantillons de surface et 111 échantillons de subsurface ont été étudiés. En outre, des analyses géochimiques (i.e. les isotopes stables du carbone, la matière organique totale et la composition élémentaire) ont été effectuées sur 384 échantillons d'affleurement. Des techniques de décantation aléatoire et de décantation par gravité ont été utilisées pour traiter les échantillons de nannofossiles. Le degré de similitude entre les associations de nannofossiles a été évalué en effectuant une analyse NMDS et une analyse UPGMA, en utilisant l'indice de similitude de Dice. La pyrolyse et la spectrométrie de masse du rapport isotopique ont été utilisées pour traiter les échantillons en vue de l'analyse de la matière organique totale et des isotopes stables, respectivement. Pour l'analyse élémentaire, la technique de diffraction des rayons X a été utilisée. Quarante-neuf espèces sont ici décrites, répartis dans neuf famillies et une espèce insertae sedis, dont cinq sont reconnues pour la première fois pour le bassin et le Pacifique sud-est. Six biozones et de nombreuses sous-zones sont reconnues en surface et subsurface, et sont en corrélation avec les schémas biostratigraphiques de la région de la Téthys. Elles correspondent au Pliensbachien à l'Aalénien moyen - Bajocien inférieur (NJT4–NJT9). Trois intervalles d'excursions isotopiques négatives accompagnées d'augmentations de la teneur en matière organique sont identifiés. Le premier d'entre eux est considéré comme l'équivalent temporel de le T-OAE. Les autres excursions de grande amplitude enregistrées au Toarcien moyen et dans l'intervalle Toarcien-Aalénien représentent le premier enregistrement de ce type pour l'intervalle Toarcien-Aalénien dans le bassin de Neuquén, et le deuxième enregistrement pour l'hémisphère sud. Les associations de nannofossiles calcaires du Pliensbachien sont liées à celles de la région de Téthys. Le Corridor hispanique est identifié comme la voie de dispersion des nannofossiles calcaires entre les océans Paléo-Pacifique et Téthys au cours du Jurassique inférieur, ce qui indique que son ouverture remonte au moins au début du Pliensbachien
Calcareous nannofossils represent a diverse group of fossils, dating back to the Late Triassic and extending their record to the present day, characterised by their calcareous composition and a size under 30 microns. Among them oustand the coccolithophorids, which constitute the most important fraction of calcareous nannoplankton, i.e. flagellated unicellular algae belonging to the Subclass Calcihaptophycidae, covered by calcium carbonate plates (coccoliths), and typically marine inhabitants of the photic zone. The representation of coccolithophorids in the fossil record corresponds to their exoskeletal remnants, commonly preserved in a disaggregated form, as individual coccoliths. Their presence in the oceans is key as they are one of the main groups of marine primary producers. Evidence from the geological record suggests that coccolithophorids have maintained their ecological requirements almost invariant over time, making them key to reconstruct palaeoenvironmental, palaeobiogeographical and palaeoclimatic conditions. The aim of this thesis is to study the calcareous nannofossil associations of Early-Middle Jurassic marine sediments, south of the Huincul High, Neuquén Basin (Argentina). By combining this information with that already available, we seek to expand and improve the biostratigraphic resources of the basin, determine similarities with assemblages from other regions of the world, and evaluate the response of these organisms to important palaeoenvironmental events. The study focuses on samples from three outcrop sections —named El Matuasto I, II and III— and two exploratory boreholes —YPF.Nq.BCE.x-1 and YPF.Nq.PTU.x-2—. A total of 102 surface samples, 20 core samples and 91 drill cuttings samples were studied. In addition, geochemical analyses (i.e., stable carbon isotopes, total organic matter and elemental composition) were performed on 384 outcrop samples. Random settling and gravity settling techniques were used to process the calcareous nannofossil samples. Quantitative analysis of nannofossils required counting at least 300 individuals; in case of a sample with low abundance, counting stopped at 450 fields of view. The degree of similarity between nannofossil associations was assessed by running NMDS and UPGMA analyses, both using the Dice index. Pyrolysis and isotope ratio mass spectrometry were used to process samples for total organic matter and stable isotope analysis, respectively. For the elemental analysis, the X-ray diffraction technique was executed. In all cases, samples containing shell remains and/or evidence of weathering were avoided. Forty-nine species are described, distributed in nine families and one species insertae sedis, of which five are recognised for the first time for the basin and the southeast Pacific area, and most of them are illustrated. Six biozones and numerous subzones are recognized on the surface and subsurface sections and correlate with biostratigraphic schemes of the Tethys region. These correspond to the Pliensbachian (Biozone NJT4) to the middle Aalenian - early Bajocian (Biozone NJT9). Three intervals of negative isotopic excursions accompanied by increases in organic matter content are identified. Applying the biostratigraphic framework, the first of these is considered to be the time-equivalent of the Toarcian Oceanic Anoxic Event (T-OAE). The other high-amplitude isotope excursions recorded in the middle Toarcian and in the Toarcian-Aalenian interval represent the first record of their kind for the Toarcian - Aalenian interval in the Neuquén Basin, and the second record for the southern hemisphere. The Pliensbachian calcareous nannofossil associations recognized in one of the sections are biogeographically related to those of the Tethys region. The Hispanic Corridor is identified as the pathway of calcareous nannofossil dispersal between the Pacific and Tethys oceans during the Early Jurassic, indicating its time of opening at least from the early Pliensbachian
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Backé, Guillaume. "Partitionnement de la déformation en zone de convergence. : Le cas des Andes vénézuéliennes et du bassin de Neuquén (Andes Centrales méridionales)." Pau, 2006. http://www.theses.fr/2006PAUU3042.

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Un régime tectonique partitionné transpressif consiste à un partage de la déformation à l'échelle d'une plaque lithosphérique entre des décrochements et des chevauchements. Les Andes offrent des conditions favorables pour étudier l'évolution tectonique de régions soumises à du partitionnement. Les Andes vénézuéliennes correspondent à un système partitionné juxtaposé à un processus d'échappement tectonique. La faille de Bocono découpe le cœur de la chaîne sur toute sa longueur. Dans la partie centrale des Andes vénézuéliennes, des failles normales limitant des blocs crustaux sont localisées au cœur d'un relais distensif de la faille de Bocono d'environ 100 km de long sur 25 km de large, lié au mouvement dextre de la faille dont l'âge serait Plio( ?)-Quaternaire. Le secteur septentrional des Andes vénézuéliennes est découpé par des failles sénestres N-S, parmis lesquelles la faille de Valéra, avec la faille de Bocono limitent à l'est et au sud le bloc crustal de Trujillo. L'analyse des déformations plio-quaternaires dans le sud de ce bloc montre qu'il est soumis à un processus d'échappement tectonique en direction de la plaque océanique Caraïbe. Le bassin de Neuquén présente des déformations plio-quaternaires compatibles avec un système partitionné caractérisé par la juxtaposition de décrochements orientés au N020°E et de chevauchements N-S. Le volcanisme d'arc plio-quaterniare est localisé dans des structures associées aux décrochements. Le volcanisme d'arrière-arc pourrait être associé à des structures chevauchantes, les principaux édifices volcaniques de la zone externe du bassin de Neuquén étant situés sur la surface sommitale d'anticlinaux
A Strain partitioning tectonic regime transpressive zones consists of an accommodation of the deformations at a lithosperical scale between strike-slip faults and thrusts. The Andes provide favourable conditions for the study of the tectonic evolution of areas subjected to such strain partitioning process. The Venezuelan Andes, located in the septentrional section of the Andes, corresponds to an area of strain partitioning juxtaposed with a process of tectonic escape. The Bocono fault cuts the belt over its entire length along its axis. In the central part of the Venezuelan Andes, nomal faults binding crustal blocks are located in the centre of a 100 km in length for 25 km in width releasing bend of the Bocono fault, linked to its right lateral movement and which age can be evaluated from the Plio(?)-Quaternary era. The septentrional section of the Venezuelan Andes is cut by a series of north-trending left lateral strike-slip faults, among which the Valera fault, along with the Bocono fault, bound the crustal-size Trujillo block. The analysis of plio-quaternary deformations in the meridional section of this block shows that it is subjected to a tectonic escape process towards the Caribbean plate. The Neuquén basin exhibits plio-quaternary deformations compatible with high-angle strain partitioning, characterised by the juxtaposition of strike slip faults trending N020°E and of N-S thrust faults. Plio-quaternary arc volcanism is associated with strike-slip faults-related structures. Back-arc volcanism could be partly associated with compressional structures, as the main volcanic vents in the external zone of the Neuquén basin are located along the anticlines axis
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Krim, Nesma. "Architecture stratigraphique, dynamique sédimentaire et distribution de la matière organique de la formation de la Vaca Muerta (Bassin de Neuquén, Argentine)." Thesis, Pau, 2015. http://www.theses.fr/2015PAUU3016/document.

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La formation de la Vaca Muerta, dans le bassin de Neuquén (Argentine), constitue le gisement non conventionnel le plus important d’Argentine. Dès lors, cette formation à la fois roche mère et roche réservoir a suscité un intérêt particulier dans le monde pétrolier afin de comprendre l’architecture des corps sédimentaires et la distribution de la matière organique de ce réservoir. L’étude menée dans le cadre de cette thèse se base sur la sédimentologie, la stratigraphie, la minéralogie et la géochimie dans le but de comprendre la logique de mise en place des systèmes de dépôt et les conditions d’oxygénation du milieu. Le but final de ce travail est de comprendre les conditions de dépôt et de préciser la relation stratigraphique entre les intervalles riches en matière organique et l'évolution du bassin (interactions entre remplissage et déformations/structuration). L’étude de sismique 3D menée dans la partie orientale du bassin a permis de déterminer un système de dépôt dominé par la houle, et montrer l’impact de la tectonique locale sur la géométrie des clinoformes et le contrôle eustatique des séquences sismiques. L’étude de terrain centrée dans un premier temps sur l’anticlinal de Picún Leufú en partie méridionale du bassin puis sur d’autres secteurs le long d’un transect nord-sud de plus de 500 km de long, a permis de mettre en évidence deux grands secteurs ayant évolué distinctement. Un secteur centro-méridional qui évolue pendant l’intervalle Tithonien-Valanginien depuis un environnement de plateforme silicoclastique vers un environnement de rampe mixte; ce secteur est alimenté essentiellement depuis le sud et le transport des sédiments vers le large est assuré par la combinaison entre des courants de dérive littorale, des courants de tempêtes et des courants gravitaires. Le second secteur au nord du bassin correspondant à la zone de Malargüe, et montre un environnement de rampe carbonatée pérenne pendant tout l’intervalle Tithonien-Valanginien. L’analyse et la synthèse stratigraphique des différents secteurs étudiés montrent un signal stratigraphique homogène avec la mise en place de cinq séquences transgressives-régressives dans le bassin pendant l’intervalle Tithonien-Valanginien. L’étude minéralogique et géochimique a permis d'évaluer l’impact du climat sur les terres émergées et par conséquent sur la distribution des sédiments vers le large. La géochimie révèle des conditions oxiques de la colonne d’eau faisant suite à une période initiale euxiniques qui coïncident avec le dépôt des niveaux les plus riches en matière organique. Enfin, la synthèse entre le signal stratigraphique et le signal géochimique montre l’existence de 4 ou 5 intervalles relativement riches en matière organique et préférentiellement localisés dans les cortèges transgressifs
The Vaca Muerta Formation is the principal source rock in the Neuquén Basin (Argentina). It constitutes also the major unconventional play in Argentina. Therefore, the Vaca Muerta formation stirs up large interest in the oil industry to understand the architecture and the organic matter distribution of this reservoir. Our study proposes an integrated approach, using sedimentology, stratigraphy, mineralogy and geochemistry in order to understand the depositional system and the paleoenvironmental conditions. The ultimate goal of this work is to clarify the stratigraphic relationship between organic-rich level and the basin filling. In the eastern part of the Neuquén basin, the study of 3D seismic allowed us to identify a wave-dominated depositional system and assess the role of the local tectonic and the eustatic control through seismic geometry. We carried out extensive field investigation, including logs and sampling, first in the Picún Leufú Anticline (southern part of the basin) and second, on several areas along a N-S trend over 500 km distance. This study allowed to define two major sectors which evolve differently. The first one corresponds to the central and southern part of the basin (from Picún Leufú Anticline to Chos Malal). There, an evolution from a siliciclastic shelf to a mixed ramp setting is observed during the Tithonian-Valanginian interval. Sediments were redistributed along the shoreface by longshore currents and further transported by storm and gravitary currents basinward. The second sector corresponds to Malargüe area (North area). It displays a perennial carbonate ramp during the Tithonian-Valanginian interval. Sequence stratigraphy analysis of all areas shows an homogeneous signal with five transgressive-regressive sequences in the basin. The geochemistry and clay mineralogy indicate the climate role in the evolution of the sedimentary environments. Geochemistry displays a “normal marine” environment with oxic waters and short-lived episodes of euxinia that coincides with the organic-rich levels. Lastly, the integrated approach, connecting stratigraphy end geochemistry shows four to five organic-rich intervals that coincide with the transgressive systems tract
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4

Larmier, Salomé. "Génération de fluides, migration et fracturation au sein des roches mères : cas de la formation de la Vaca Muerta, bassin de Neuquén, Argentine." Thesis, Le Mans, 2020. http://cyberdoc-int.univ-lemans.fr/Theses/2020/2020LEMA1009.pdf.

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Les fractures hydrauliques naturelles engendrées par des phénomènes de surpression de fluide sont courantes dans les roches mères. Elles se matérialisent généralement par des veines de calcite plus communément appelées « beef ». L’étude de ces veines permet de mieux contraindre l’'histoire tectonique et thermique du bassin. De plus, la compréhension de leur répartition spatiale est un paramètre clef pour l’exploitation pétrolière non-conventionnelle, les beef jouant sur le développement de la fracturation hydraulique induite. Ce travail présente une approche multidisciplinaire dans le domaine des géosciences pour contraindre au mieux le timing, la répartition, la morphologie et l’origine des fluides alimentant les beef. Le cas d’étude porte sur les beef de la formation de la Vaca Muerta, bassin de Neuquén, Argentine. Les résultats des études effectuées sur des carottes sédimentaires et des affleurements de terrain ont montrés que les hétérogénéités sédimentaires, les valeurs de TOC élevées, la maturité de la roche et les contraintes tectoniques compressives contrôlaient la fréquence ainsi que l’épaisseur des beef. Ainsi, ils deviennent des marqueurs de la maturité de la roche. Les beef présentent une morphologie 3D variant en fonction de la composition de la roche encaissante. Des observations pétrographiques ont permis de démontrer qu’ils enregistrent les déformation tectoniques contemporaines et postérieures de leur ouverture. Les fluides alimentant ces fractures évoluent au cours du temps et évoluent localement en fonction de la composition minéralogique de la roche encaissante et de la température. Pour conclure, les beef se mettent en place mécaniquement par l’action des pressions de fluides et / ou de la contrainte tectonique compressive, au maximum de l’enfouissement et au début de l’exhumation du bassin
Natural hydraulic fractures caused by fluid overpressure phenomena are common in source rocks. They generally materialize in calcite veins more commonly known as "beef". The study of these veins makes it possible to better constrain the tectonic and thermal history of the basin. Moreover, understanding their spatial distribution is a key parameter for unconventional oil exploitation, as the beef plays an important role on the development of induced hydraulic fracturing. This work presents a multidisciplinary approach in the field of geosciences to constrain the timing, distribution, morphology and origin of the fluid feeding the beef. The case study is from the Vaca Muerta formation, Neuquén basin, Argentina. The results of studies carried out on sediment cores and outcrops showed that sedimentary heterogeneities, high TOC values, rock maturity and compressive tectonic stresses controlled the frequency and thickness of the beef. Thus, they become markers of rock maturity. Beefs have a 3D morphology that varies according to the surrounding rock. Petrographic observations have shown that they record the contemporary and posterior deformation of their opening. The fluids that feed these fractures evolve over time and change locally according to the mineralogical composition of the surrounding rock and temperature. To conclude, the beefs are mechanically set in place by the action of fluid pressure and/or compressive tectonic stress, at the maximum burial and at the beginning of the exhumation of the basin
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5

Matthieu, Branellec. "Impact du mode de propagation des fronts orogéniques sur la géométrie, la localisation et la chronologie de la déformation : Cas du Bassin de Neuquén, (Argentine)." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3042/document.

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Cette thèse traite de l’enregistrement de la déformation, à différentes échelles de temps et d’espace dans la chaîne plissée de Malargüe et le bloc de San Rafael, situés dans la partie septentrionale du bassin de Neuquén en Argentine. La première partie du travail comprend une analyse de la déformation finie (chaîne de Malargüe) et de la déformation active (bloc de San Rafael) à l’échelle macroscopique. De manière générale, les coupes structurales régionales proposées mettent clairement en évidence le rôle l’héritage structural lié aux structures générées lors de l’ouverture du bassin au Jurassique. Nous montrons également que les mécanismes de soulèvement actuels du bloc de San Rafael à l’est reprennent les modalités de la déformation d’âge Miocène dans la chaîne. Contrairement au mode de structuration des prismes critiques classiques caractérisés par la localisation de la déformation le long d’un niveau de décollement, la structuration de la chaîne est ici issue d’une déformation distribuée plus largement dans la lithosphère. A l’échelle de l’endommagement mesoscopique, la fracturation régionale nous a permis d’enregistrer les différents champs de contraintes régionaux liés aux phases de raccourcissement depuis le domaine pré-plissement jusqu’à la phase syn-plissement. Ces différentes phases sont en accord avec la cinématique de la convergence de la plaque Nazca depuis le Crétacé supérieur. A l’échelle microscopique, l’analyse des propriétés de susceptibilité magnétique des roches met en évidence, d’une part, une compartimentalisation de la déformation à l’échelle de la matrice liée à l’héritage structural extensif. D’autre part, la distribution spatiale de cet endommagement ne démontre pas l’existence de gradient clair des fabriques magnétiques depuis l’avant-pays vers les zones internes ce qui confirme le caractère atypique du système Andin à la latitude de 35°S. Ce dernier étant principalement contrôlé par une déformation distribuée, liée à l’héritage structural et singulièrement différente de celle attendu dans le cadre de la théorie du prisme critique
This PhD project deals with multiscale record of the tectonic signal in the Malargüe fold-and-thrust-belt (MFTB) located in the northern part of the Neuquén basin (Argentina). The first results presented rely on the study of the macroscopic finite strain in the fold-belt and the characterization of the active deformation of the San Rafael Block uplift. The cross-sections we produce show that structural inheritance related to the Jurassic extension is the main parameter controlling the belt structure. In addition we proposed that the building mechanisms that controlled the MFTB evolution by Miocene times are the same than those triggering the present day San Rafael block uplift. The second part of this work is dedicated to mesoscopic strain pattern analysis recorded by fracture networks. Throughout the MFTB, we are able to describe the occurrence of four main fractures sets emplaced in several stress regime that are linked (1) to the inheritance and (2) to the well-known compression phases from pre-folding to syn-folding settings. Finally the third part of this work describes the microscopic damage recorded by the anisotropy of magnetic susceptibility method. We mainly evidence that there is no clear gradient of magnetic fabrics from foreland to hinterland and that deformation is compartmentalized by structural inheritance. This atypical pattern of magnetic fabrics succession reveals that the matrix damage is governed by the same strain distribution as those observed at macroscopic scale thus providing a supplementary argument to consider the Andean system at these latitudes as singularly different from a classical Coulomb wedge
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