Letteratura scientifica selezionata sul tema "Transition marine à continentale"

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Articoli di riviste sul tema "Transition marine à continentale"

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Bera, M. K., A. Sarkar, P. P. Chakraborty, R. S. Loyal e P. Sanyal. "Marine to continental transition in Himalayan foreland". Geological Society of America Bulletin 120, n. 9-10 (1 settembre 2008): 1214–32. http://dx.doi.org/10.1130/b26265.1.

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Liu, Chao, Hai Tao Xue, Shuang Wang e Yu Jiao Sun. "Study on Law of Structural Evolution and Sedimentary Evolution for North Uskyurt Basin". Advanced Materials Research 671-674 (marzo 2013): 302–5. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.302.

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North Uskyurt Basin, located on Turan Plain, northwestern Central Asian, is continental polycyclic cratonic. The structural evolution of the basin underwent six phases: basement formulation, passive edge, rifting, post-rifting, compression, early Neogene depression. Regional structural evolution takes control of complicated transition of North Uskyurt sedimentary structure. In general, basin sedimentary environment underwent basement (granite, metamorphic rocks) passive edge, late Devonian epoch carboniferous period (marine facies) rifting, late Permian epoch-triassic period (continental facies) post-rifting, Jurassic period-Cretaceous period (Marine-continental Transition Facies, marine facies) compression, late Eocene-Miocene epoch (marine-continental facies coexistence) Neogene depression, Pliocene-Holocene (continental facies). Consequently, sedimentary formation in which various sedimentary environment, such as marine facies, continental facies, are coexisted with various rock types, such as clastic rocks, carbonate rocks, is generated.
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Singh, B. P. "Marine to continental transition in Himalayan foreland: Discussion". Geological Society of America Bulletin 122, n. 5-6 (6 aprile 2010): 954–55. http://dx.doi.org/10.1130/b26532.1.

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Bera, M. K., A. Sarkar, P. P. Chakraborty, R. S. Loyal e P. Sanyal. "Marine to continental transition in Himalayan foreland: Reply". Geological Society of America Bulletin 122, n. 5-6 (6 aprile 2010): 956–59. http://dx.doi.org/10.1130/b26591.1.

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Wei, Zhifu, Yongli Wang, Gen Wang, Ting Zhang, Wei He, Xueyun Ma e Xiaoli Yu. "Enrichment Mechanism of the Upper Carboniferous-Lower Permian Transitional Shale in the East Margin of the Ordos Basin, China: Evidence from Geochemical Proxies". Geofluids 2020 (6 novembre 2020): 1–14. http://dx.doi.org/10.1155/2020/8867140.

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The organic-rich shale of the Upper Carboniferous-Lower Permian transition period in the eastern margin of the Ordos Basin, China, was formed in a marine-continental facies sedimentary environment. With a high content of total organic carbon (TOC) and a large cumulative thickness, it is considered a good source rock for shale gas development. The sedimentary environment of marine-continental transitional shale is obviously different from that of marine shale, which leads to different enrichment characteristics of organic matter. In this paper, shale samples were collected from XX# well of the Taiyuan and Shanxi Formations across the Upper Carboniferous-Lower Permian, which is typical marine-continental transitional shale. The TOC, major elements, and trace elements were measured, and the formation and preservation conditions were investigated using multiple geochemical proxies, including paleoclimate, redox parameters, paleoproductivity, and controls on the accumulation of organic matter. The TOC of Shanxi Formation is higher than that of Taiyuan Formation. In the Taiyuan Formation, TOC is positively related to the redox index (V, U, and V/Cr), indicating that the dysoxic bottom water environment is the key factor controlling organic matter accumulation. For Shanxi Formation, there is a positive correlation between TOC and paleoclimate, which indicates that the enrichment of organic matter is affected by warm and humid paleoclimate and oxic environment. In addition, the paleoproductivity is lower with a positive correlation with TOC for the marine-continental transitional organic-rich shale, suggesting that it was inferior to the gathering of organic matter.
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Mourier, Thomas, Peter Bengtson, Michel Bonhomme, Emile Buge, Henri Cappettta, Jean-Yves Crochet, Monique Feist et al. "The Upper Cretaceous - Lower Tertiary marine to continental transition in the Bagua basin, northern Peru - Paleontology, biostratigraphy, radiometry, correlations". Newsletters on Stratigraphy 19, n. 3 (26 ottobre 1988): 143–77. http://dx.doi.org/10.1127/nos/19/1988/143.

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Cui, Z., S. Davies, K. S. Carslaw e A. M. Blyth. "The response of precipitation to aerosol through riming and melting in deep convective clouds". Atmospheric Chemistry and Physics Discussions 10, n. 11 (25 novembre 2010): 29007–50. http://dx.doi.org/10.5194/acpd-10-29007-2010.

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Abstract. We have used a 2-D axisymmetric, non-hydrostatic, bin-resolved cloud model to examine the impact of aerosol changes on the development of mixed-phase convective clouds. We have simulated convective clouds from four different sites (three continental and one tropical marine) with a wide range of realistic aerosol loadings and initial thermodynamic conditions (a total of 93 different clouds). It is found that the accumulated precipitation responds very differently to changing aerosol in the marine and continental environments. For the continental clouds, the scaled total precipitation reaches a maximum for aerosol that produce drop numbers at cloud base between 180–430 cm−3 when other conditions are the same. In contrast, all the tropical marine clouds show an increase in accumulated precipitation and deeper convection with increasing aerosol loading. For continental clouds, drops are rapidly depleted by ice particles shortly after the onset of precipitation. The precipitation is dominantly produced by melting ice particles. The riming rate increases with aerosol when the loading is very low, and decreases when the loading is high. Peak precipitation intensities tend to increase with aerosol up to drop concentrations (at cloud base) of ~500 cm−3 then decrease with further aerosol increases. This behaviour is caused by the initial transition from warm to mixed-phase rain followed by reduced efficiency of mixed-phase rain at very high drop concentrations. The response of tropical marine clouds to increasing aerosol is different to, and larger than, that of continental clouds. In the more humid tropical marine environment with low cloud bases we find that accumulated precipitation increases with increasing aerosol. The increase is driven by the transition from warm to mixed-phase rain. Our study suggests that the response of deep convective clouds to aerosol will be an important contribution to the spatial and temporal variability in cloud microphysics and precipitation.
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Cui, Z., S. Davies, K. S. Carslaw e A. M. Blyth. "The response of precipitation to aerosol through riming and melting in deep convective clouds". Atmospheric Chemistry and Physics 11, n. 7 (15 aprile 2011): 3495–510. http://dx.doi.org/10.5194/acp-11-3495-2011.

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Abstract. We have used a 2-D axisymmetric, non-hydrostatic, bin-resolved cloud model to examine the impact of aerosol changes on the development of mixed-phase convective clouds. We have simulated convective clouds from four different sites (three continental and one tropical marine) with a wide range of realistic aerosol loadings and initial thermodynamic conditions (a total of 93 different clouds). It is found that the accumulated precipitation responds very differently to changing aerosol in the marine and continental environments. For the continental clouds, the scaled total precipitation reaches a maximum for aerosol that produce drop numbers at cloud base between 180–430 cm−3 when other conditions are the same. In contrast, all the tropical marine clouds show an increase in accumulated precipitation and deeper convection with increasing aerosol loading. For continental clouds, drops are rapidly depleted by ice particles shortly after the onset of precipitation. The precipitation is dominantly produced by melting ice particles. The riming rate increases with aerosol when the loading is very low, and decreases when the loading is high. Peak precipitation intensities tend to increase with aerosol up to drop concentrations (at cloud base) of ~500 cm−3 then decrease with further aerosol increases. This behaviour is caused by the initial transition from warm to mixed-phase rain followed by reduced efficiency of mixed-phase rain at very high drop concentrations. The response of tropical marine clouds to increasing aerosol is different to, and larger than, that of continental clouds. In the more humid tropical marine environment with low cloud bases we find that accumulated precipitation increases with increasing aerosol. The increase is driven by the transition from warm to mixed-phase rain. Our study suggests that the response of deep convective clouds to aerosol will be an important contribution to the spatial and temporal variability in cloud microphysics and precipitation.
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Mai, Ana C. G., Lizandra J. Robe, Luis F. Marins e João P. Vieira. "Genetic relationships between landlocked and coastal populations of Lycengraulis grossidens (Engraulidae) in south-eastern South America: evidence for a continental colonisation route with secondary transitions to the coastal region". Marine and Freshwater Research 68, n. 2 (2017): 342. http://dx.doi.org/10.1071/mf15355.

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The anchovies of the genus Lycengraulis are the product of an evolutionary transition from a marine to freshwater environment that occurred in South America during the Miocene epoch. Lycengraulis grossidens originated from freshwater lineages and is currently distributed in estuaries and coastal zones. Nevertheless, based on otolith chemistry, there are landlocked individuals in the Uruguay River. The aim of the present study was to investigate the spatiotemporal scenario by which these landlocked individuals reached their current distribution: whether through a north-to-south continental route based on the connection between basins or from the marine environment. To this end, a fragment of the mitochondrial (mt)DNA control region was analysed from individuals collected along freshwater, estuarine and marine environments. We found a significant genetic differentiation between freshwater and coastal (estuarine and marine) populations. Larger haplotype diversities and female effective population size values were found in the coastal population. Nevertheless, the outgroup rooting positioned some Uruguay River haplotypes as hypothetical ancestors in the directed network and as early offshoots in the phylogeny, suggesting the landlocked population as an ancestral lineage. Therefore, the phylogenetic history and biogeography are consistent with a north-to-south continental colonisation route putatively associated with ancient connections between the Amazon and Parana basins followed by new evolutionary transitions to the coastal region associated with Quaternary sea level oscillations.
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Cortés Sánchez, Miguel, Francisco J. Jiménez Espejo, María D. Simón Vallejo, Juan F. Gibaja Bao, António Faustino Carvalho, Francisca Martinez-Ruiz, Marta Rodrigo Gamiz et al. "The Mesolithic–Neolithic transition in southern Iberia". Quaternary Research 77, n. 2 (marzo 2012): 221–34. http://dx.doi.org/10.1016/j.yqres.2011.12.003.

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New data and a review of historiographic information from Neolithic sites of the Malaga and Algarve coasts (southern Iberian Peninsula) and from the Maghreb (North Africa) reveal the existence of a Neolithic settlement at least from 7.5 cal ka BP. The agricultural and pastoralist food producing economy of that population rapidly replaced the coastal economies of the Mesolithic populations. The timing of this population and economic turnover coincided with major changes in the continental and marine ecosystems, including upwelling intensity, sea-level changes and increased aridity in the Sahara and along the Iberian coast. These changes likely impacted the subsistence strategies of the Mesolithic populations along the Iberian seascapes and resulted in abandonments manifested as sedimentary hiatuses in some areas during the Mesolithic–Neolithic transition. The rapid expansion and area of dispersal of the early Neolithic traits suggest the use of marine technology. Different evidences for a Maghrebian origin for the first colonists have been summarized. The recognition of an early North-African Neolithic influence in Southern Iberia and the Maghreb is vital for understanding the appearance and development of the Neolithic in Western Europe. Our review suggests links between climate change, resource allocation, and population turnover.
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Tesi sul tema "Transition marine à continentale"

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Brionne, Charles. "Signatures morphosédimentaires de la dynamique juxta-glaciaire à la transition de fronts glaciaires marins à terrestres : le cas de la Côte-Nord du Québec (estuaire et golfe du St Laurent)". Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAH005.

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Cette thèse combine une double approche géomorphologique et sédimentologique associée à l’utilisation de données LiDAR, bathymétriques, photogrammétrie drone et de datations radiocarbones. Elle a permis de reconstituer les paléos dynamiques glaciaires en contexte de déglaciation pour l’Inlandsis Laurentidien depuis le dernier maximum glaciaire, il y a environ 20 000 ans, et plus précisément au passage d’une marge glaciaire ancrée en mer à une marge glaciaire continentale Deux études ont été menées conjointement, soit : (1) la cartographie, la synthèse et la proposition d’un modèle concernant les mégacannelures de la Côte-Nord du Saint-Laurent, une première pour ces morphologies et (2) la reconstruction de l’enregistrement géomorphologique et morphosédimentaire du complexe sédimentaire de Pentecôte, mimant précisément cette transition. D’une manière générale, cette thèse démontre l’importance de l’héritage structural et de la physiographie du plancher au marge glaciaire dans la reconstruction de la dynamique glaciaire de retrait de la marge du LIS oriental
This thesis combines a dual geomorphological and sedimentological approach with the use of LiDAR data, bathymetry, drone photogrammetry and radiocarbon dating. It has enabled us to reconstruct the glacial paleodynamics in a deglaciation context for the Laurentide ice sheet since the last glacial maximum, around 20,000 years ago, and more specifically during the transition from an ice margin anchored at sea to a continental ice margin: (1) mapping, synthesising and proposing a model for the megagrooves of the North Shore of the St Lawrence, a first study for these morphologies, and (2) reconstructing the geomorphological and morphosedimentary record of the Pentecôte sedimentary complex, which precisely represents this transition. Overall, this thesis demonstrates the importance of the structural heritage and physiography of the floor at the glacial margin in the reconstruction of the glacial retreat dynamics of the eastern LIS margin
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Alves, Luizemara Soares. "Estudo da margem continental ibérica ocidental com base em dados gravimétricos e magnetométricos regionais". Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6240.

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Abstract (sommario):
Os métodos potenciais são conhecidos como uma ferramenta útil para estudos regionais. Na Ibéria Ocidental, a gravimetria e a magnetometria podem ser utilizadas para auxiliar no entendimento de algumas questões sobre a estruturação tectônica offshore. Nesta região, tanto as estruturas geradas pela quebra continental, quanto às herdadas do embasamento variscano, tem uma importante contribuição para a resposta geofísica regional observada com estes métodos. Este trabalho tem como objetivo correlacionar as feições geofísicas observadas com alguns modelos geológicos do arcabouço tectônico da Ibéria Ocidental já publicados na literatura. Mapas filtrados foram usados para auxiliar no reconhecimento de diferentes assinaturas geofísicas, os quais foram calculados a partir dos mapas de gravidade Bouguer e do campo magnético total tais como o gradiente horizontal total, derivada tilt, derivada vertical, e integral vertical. O domínio crustal continental foi definido a partir da interpretação dos dados gravimétricos, utilizando gradiente de gravidade horizontal total da Anomalia Bouguer. Os dados magnéticos, originais e filtrados, foram utilizados para identificar mais três domínios regionais offshore, que sugerem a existência de três tipos de crosta não-siálica. Dois deles são propostos como domínios de transição. A região da crosta de transição mais próxima do continente tem uma fraca resposta regional magnética, e a porção mais distal é um domínio de anomalia de alta amplitude, semelhante à resposta magnética oceânica. O limite crustal oceânico não pôde ser confirmado, mas um terceiro domínio offshore, a oeste da isócrona C34, poderia ser considerado como crosta oceânica, devido ao padrão magnético que apresenta. Alguns lineamentos do embasamento foram indicados na crosta continental offshore. As feições gravimétricas e magnéticas interpretadas coincidem, em termos de direção e posição, com zonas de sutura variscanas, mapeados em terra. Assim, esses contatos podem corresponder à continuação offshore destas feições paleozoicas, como o contato entre as zonas de Ossa Morena-Zona Centro-Ibérica. Nesta interpretação, sugere-se que a crosta continental offshore pode ser composta por unidades do Sudoeste da Península Ibérica. Isto permite considerar que a Falha de Porto-Tomar pertence a uma faixa de deformação strike-slip, onde parte das bacias mesozoicas da margem continental está localizada.
Potential field methods are known as a very useful tool to regional studies. On Western Iberia, gravimetric and magnetometric data could be helpful to understand some questions about the offshore tectonic framework. In this area, both continental break-up features and inherited continental basement structures have a strong contribution to compose the regional geophysical response on gravimetric and magnetometric maps. This work aims to correlate observed geophysical features of the Iberian margin with some geological models about the tectonic framework of Western Iberia, already published on literature. Filtered maps were used to recognize different geophysical signatures, which were computed from both calculated Bouguer gravity and total magnetic field, such as total horizontal gradient, tilt derivative, vertical derivative, and vertical integration. The continental crustal domain was defined from gravity data interpretation using an enhanced total horizontal gradient of Bouguer Anomaly maps. Magnetic data was used to identify three more regional offshore domains that could indicate three types of non-sialic crust. Two of them are proposed as transitional domains. The landward transitional crust has a very weak regional magnetic response, and the seaward one is a high amplitude anomaly domain, similar to oceanic magnetic response. The oceanic crustal boundary was not confirmed, but a third offshore domain, seaward from C34 isochron, could be considered as oceanic crust by its magnetic pattern. Some basement lineaments were indicated in the offshore continental crust. Gravimetric and magnetic features coincide in terms of their direction and position with Variscan suture zones mapped onshore. Therefore these contacts could correspond the offshore continuation of these Paleozoic features, such as the Ossa-Morena Zone and Centro-Ibérica Zone suture zone. In this interpretation, offshore continental crust could be formed by units from Southwest Iberia. It allows considering the Porto-Tomar fault as a part of a swath of strike-slip deformation, where mesozoic basins are located.
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Bouton, Anthony. "Facteurs de contrôle extrinsèques des dépôts microbiens récents en domaine de transition continental-marin". Thesis, Dijon, 2016. http://www.theses.fr/2016DIJOS012/document.

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Les microbialites, dépôts lithifiés d’origine microbienne, sont des structures organosédimentaires documentées depuis plus de 3,5 milliards d’années. La compréhension de ces structures, des conditions et des modalités de leur mise en place, nous apporte des informations précieuses sur l’origine de la vie sur Terre. Cette thématique de recherche est également en plein essor du fait de ses implications économiques majeures concernant les hydrocarbures. La reconstitution des environnements associés aux structures microbiennes fossiles reste incertaine, notamment entre milieux de dépôts marins ou continentaux. Ces deux environnements contrastés ont été étudiés à travers deux exemples modernes, Cayo Coco (Cuba) en domaine marin lagunaire et le Grand Lac Salé (Utah, USA) en domaine lacustre continental dans le but d’identifier des critères diagnostiques pour discriminer ces environnements dans le registre fossile.La formation des microbialites résulte de la minéralisation et de la lithification d’un tapis microbien sous l’influence d’une composante métabolique (intrinsèque) liée à l’activité du tapis microbien, et d’une composante environnementale (extrinsèque). L’objectif de ce travail était de replacer à différentes échelles les dépôts microbiens dans leur contexte environnemental et de comprendre les influences directes des paramètres extrinsèques sur : (1) les processus de minéralisation des tapis microbiens et la formation de microbialites, (2) la morphologie des structures microbiennes, (3) la distribution spatio-temporelle des microbialites et des sédiments associés, et enfin (4) les relations entre les tapis microbiens et microbialites et leur environnement
Lithified microbial deposits, considered as microbialites, are organosedimentary structures observed since 3.5 billion years. Understanding the mechanisms and environmental conditions leading to their formation may provide valuable information about the origin of life on Earth. Our interest on this research topic has increased owing to the economic implications of these deposits, especially concerning the hydrocarbons. The reconstruction of the environments associated with microbial structures remains uncertain in the fossil record, especially between marine and continental domains. These two contrasting environments were studied through two modern examples: (1) a marine-fed lagoon area in Cayo Coco (Cuba), and the continental lake of the Great Salt Lake (Utah, USA) in order to identify diagnostic criteria allowing to distinguish both environments in the fossil record.Microbialite result from mineralization and lithification of microbial mats under the influence of metabolic chemical reactions (intrinsic) related to the activity of the microbial biomass and environmental (extrinsic) conditions. The objective of this PhD is to replace microbial deposits, at different scales, in their context of formation to highlight the significance of extrinsic parameters on: (1) the mineralization processes and the formation of microbialites, (2) the morphologies of observed microbial structures, (3) their spatial distribution, and (4) the relationship between microbial mats and microbialite and their environment
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TODDE, SAMUELE. "Geomorfologia del Margine Continentale della Sardegna meridionale". Doctoral thesis, Università degli Studi di Cagliari, 2014. http://hdl.handle.net/11584/266413.

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The study submitted in this thesis is related to the continental margin of southern Sardinia, including the continental platform and the upper portion of the continental slope to a depth of about 2000 meters, is included within the Gulf of Cagliari, limited to the west by Capo Teulada and on the east by Capo Carbonara. The continental margin of southern Sardinia has been investigated for the first time through high resolution morphobatimetric (multibeam) data not interpolated. Have been defined Geo Risks associated with characteristics of escarpment‟s gravitational processes and the dynamics of channeled flows that affect the evolution of systems of canyons. The multibeam data have been acquired during two cruises: MaGIC Canale di Sardegna 2009 and MaGIC Sardegna 2010, whit the research ship “Universitatis”; Subbottom Profile data have been acquired to support the geological interpretation. The classification of the morphobatimetric elements identified the continental shelf, the slope, areas of diffused erosion, canyons and channels and areas affected by big submarine landslides. The detailed morphometric analysis carried out for each system of canyons and channel offered further information on the evolution dynamics and on the state of activity of the margin. Were detected evidence related to uplift movements for the Sarroch Canyon, which present meander features and at least three orders of terraces. In the Pula Canyon area was observed the absence of intra-channel storage, index of tectonic activity related to the recent evolution of the western margin of the Gulf of Cagliari. Have been studied in detail five great submarine landslides in the Gulf of Cagliari, including the margin between the continental shelf and the upper continental slope. Models have been proposed of the evolutionary dynamics and triggering of landslides, related the slowly tectonic influence, the presence of hydrates, within the sedimentary package, and finally the seismic triggering as the main factor of initiation of underwater landslides
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Fabre, Sébastien. "Altération continentale et sédimentation marine au Précambrien : marqueurs de l'évolution chimique des enveloppes fluides terrestres". Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00542803.

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Ce travail multidisciplinaire vise à exploiter les enregistrements de l'évolution des enveloppes fluides terrestres au Précambrien (altération continentale et de la sédimentation marine). Des BIFs archéens (Carajás, Brésil) attestent de l'oxydation incomplète du fer dissous océanique, alors que des grès à pyrites indiquent la pauvreté en sulfates océaniques. Des expériences annuelles d'altération de roches en conditions précambriennes, support d'un modèle numérique, encadrent le temps requis pour que la pCO2 atm diminue de 300 PAL (Present Atmospheric Level) à 1 PAL entre 200 000 et 500 000 ans suite aux glaciations globales néoprotérozoïques. La consommation précambrienne de CO2atm, inférieure à l'Actuel, s'explique par l'absence de végétaux terrestres. Enfin, la modélisation de la précipitation abiotique des cap carbonates néoprotérozoïques montre que le dégazage et/ou l'évaporation d'un océan riche en CO2 expliquent la formation de ces roches au sortir des glaciations globales.
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Acremont, Elia d'. "De la déchirure continentale à l'accrétion océanique : ouverture du Golfe d'Aden". Paris 6, 2002. http://www.theses.fr/2002PA066383.

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Régnier, Damien. "Modélisation physique et numérique de la dynamique d’un pergélisol au cours d’un cycle climatique : implications pour le site de Meuse - Haute-Marne". Rennes 1, 2012. http://www.theses.fr/2012REN1S054.

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Ce mémoire présente les travaux réalisés sur la modélisation de la dynamique d’un pergélisol (sol dont la température est inférieure à 0°C durant 2 ans consécutifs) et de son impact sur les circulations hydrogéologiques. Ils contribuent aux études de l’Andra sur le stockage des déchets radioactifs et sur l’étude environnementale du site Meuse/Haute-Marne. Lors d’un cycle climatique, les périodes froides peuvent générer l’installation d’un pergélisol. Cette structure périglaciaire se propage vers les horizons géologiques profonds, et de par sa très faible perméabilité, peut immobiliser des masses d’eau importantes dans les aquifères. Ce travail présente l’élaboration de deux modèles numériques à l’aide du code Cast3M (CEA) : (i) un modèle thermique conductif pur, adaptation d’une procédure existante, pour l’étude de la propagation d’ondes de froid en milieu poreux avec transition de phase eau-glace ; (ii) un modèle élaboré, gérant le couplage thermo-hydraulique des processus du sous-sol (conduction, convection et transition de phase). Validés, ces deux modèles offrent ici trois axes de valorisation : (i) proposition d’un benchmark par l’étude de deux cas tests génériques ; (ii) étude du signal de température imposé en surface : importance des variations climatiques haute fréquence (échelle centennale) sur la propagation et la stabilité d’un pergélisol ; (iii) étude de la dynamique d’une discontinuité thermique dans un système hydrologique type rivière-plaine : temps de fermeture du système par le pergélisol selon différents paramètres (températures, flux géothermique, sens des flux hydrologiques…). Ces points étant directement reliés aux problématiques du site Andra
This manuscript deals about works realized on the permafrost modelling in porous media and its impact on the hydrogeological circulations. These are parts of the Andra’s studies on the nuclear waste storage and, on the environmental studies of the Meuse/Haute-Marne (MHM) site. During a climatic cycle, cold periods can generate permafrost (ground with temperature lower than 0°C for 2 consecutive years). This periglacial structure propagates towards deep geological layers, and, due to its very low permeability, can stop the flow of water bodies like aquifers. This work presents the elaboration of two numerical models (with Cast3M code (CEA)): (i) a model with thermal conduction, used for the study of a cold wave propagation in porous media with phase transition (water-ice); (ii) a more complex model, managing the thermo-hydraulic coupling of ground phenomenon (conduction, convection and transition of phase). After validation, these two models offer three axes of development: (i) benchmark proposition by the study of two generic test-cases; (ii) study of the local air temperature signal on MHM site : importance of high frequency temperature variations (centennial scale) for permafrost depth and stability ; (iii) study of the dynamics of a thermal discontinuity in a typical hydrological system river-plain: closure time of the system by the permafrost according to various parameters (temperatures, geothermal flow, hydrological flow directions). These points are directly linked with the problems of the MHM site
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Imbert, Hélène. "Stratégie conditionnelle contrôlant la dispersion continentale de l'anguille européenne". Bordeaux 1, 2008. http://www.theses.fr/2008BOR13598.

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L'objectif de ce travail de thèse est de tester si la dispersion des anguilles dans les bassins versants peut être considérée comme une stratégie conditionnelle où la nature et les signaux déclencheurs des mouvements changent durant l'ontogénie. Un programme de marquage-recapture est développé en amont de limite de marée dynamique afin de caractériser les facteurs endogènes contrôlant les différentes tactiques de déplacement. Les anguillettes métamorphosées (anguilles de 60 à 150 mm) adoptent un comportement majoritairement migrant tandis que les anguilles jaunes (individus de plus de 200 mm) adoptent un comportement majoritairement sédentaire. Chez les anguillettes, la migration amont est déclenchée par une forte activité de la glande thyroïde chez les individus en bonne condition corporelle. Chez les anguilles jaunes, les individus en déplacement sont minoritaires et présentent des signes de stress physiologique, suggérant que les mouvements des anguilles jaunes répondent principalement à des interactions agonistes. Ainsi, la diversité de patterns de dispersion des anguilles dans les habitats continentaux pourrait être contrôlée par une transition ontogénique. Celle-ci a lieu entre le stade anguillette qui migre vers l'amont lorsque son statut énergétique le permet et le stade anguille jaune sédentaire qui se déplace à la recherche de nourriture et d'habitat. En nous basant sur un modèle conceptuel de stratégie évolutionnairement stable (ESS), nous suggérons que les changements de densité de population sont cruciaux dans l'expression et l'évolution de ces comportements.
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Nowicki, Sophie Marie Jeanne. "Modelling the transition zone of marine ice sheets". Thesis, University College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499076.

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Gueydan, Frédéric. "La transition fragile-ductile de la croûte continentale en extension : du terrain à la modélisation". Paris 6, 2001. http://www.theses.fr/2001PA066514.

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Libri sul tema "Transition marine à continentale"

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Valentine, Page C. The shelf-slope transition--canyon and upper slope sedimentary processes on the southern margin of Georges Bank: An examination of sedimentary environments in water depths of 150-600 meters and of how they are determined by the interaction of available sediment, bottom currents, and sea-floor morphology. Washington, D.C: U.S. G.P.O., 1987.

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Valentine, Page C. The shelf-slope transition--canyon and upper slope sedimentary processes on the southern margin of Georges Bank: An examination of sedimentary environments in water depths of 150-600 meters and of how they are determined by the interaction of available sediment, bottom currents, and sea-floor morphology. Washington, DC: U.S. Geological Survey, 1987.

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Tomoya, Akimichi, a cura di. Coastal foragers in transition. Osaka: National Museum of Ethnology, 1996.

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R, Prothero Donald, Ivany Linda C e Nesbitt Elizabeth R, a cura di. From greenhouse to icehouse: The marine Eocene-Oligocene transition. New York: Columbia University Press, 2003.

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name, No. From greenhouse to icehouse: The marine Eocene-Oligocene transition. New York: Columbia University Press, 2003.

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Lei, Guobin. Geochemical processes controlling transition metal distributions in marine manganese concretions and sediments. Stockholm, Sweden: Dept. of Geology and Geochemistry, Stockholm University, 1995.

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A, Wetherall Jerry, Southwest Fisheries Science Center (U.S.). Honolulu Laboratory, University of Hawaii (Honolulu). Joint Institute for Marine and Atmospheric Research e United States. National Marine Fisheries Service, a cura di. Biology, oceanography, and fisheries of the North Pacific transition zone and subarctic frontal zone: Papers from the North Pacific Transition Zone Workshop, Honolulu, Hawaii, 9-11 May 1988. [Washington, D.C.]: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 1991.

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S, Savino Carl. The military-to-civilian transition guide: A career transition guide for Army, Navy, Air Force, Marine Corps & Coast Guard personnel. 2a ed. Fairfax Station, VA: Competitive Edge Services, 2011.

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Scharek, Renate. Die Entwicklung des Phytoplanktons im östlichen Weddellmeer (Antarktis) beim Übergang vom Spätwinter zum Frühjahr =: Development of phytoplankton during the late-winter/spring transition in the eastern Weddell Sea (Antarctica). Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 1991.

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Reims, Université de, a cura di. Recherches en aménagement du territoire, en glaciologie fluviale, marine et continentale, sur le quaternaire (glaciaire et périglaciare) en géomorphologie et en tectonique. Lille: A.N.R.T, Université de Lille III, 1985.

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Capitoli di libri sul tema "Transition marine à continentale"

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Mather, Anne E., e Martin Stokes. "Marine to Continental Transition". In A Field Guide to the Neogene Sedimentary Basins of the Almería Province, SE Spain, 186–224. Oxford, UK: Blackwell Publishing Ltd., 2009. http://dx.doi.org/10.1002/9781444300604.ch5.

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Chakraborty, Nivedita, Subir Sarkar e R. Nagendra. "Continental-to-Marine Transition in an Ongoing Rift Setting: Barremian-Turonian Sediments of Cauvery Basin, India". In Mesozoic Stratigraphy of India, 587–622. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-71370-6_20.

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May, Vincent. "Softer Solutions to Coastal Erosion: Making the Transition from Resistance to Resilience". In Coastal Systems and Continental Margins, 1–16. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0135-9_1.

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Gomes, Paulo Otávio, Benedito S. Gomes, Jorge J. C. Palma, Koji Jinno e Jairo M. de Souza. "Ocean-continent transition and tectonic framework of the oceanic crust at the continental margin off NE Brazil: Results of LEPLAC project". In Atlantic Rifts and Continental Margins, 261–91. Washington, D. C.: American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm115p0261.

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Stal, Lucas J. "Coastal Sediments: Transition from Land to Sea". In The Marine Microbiome, 283–304. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-33000-6_10.

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Dere, Caglar. "Hydrogen as a Transition Fuel in Marine Engines". In Springer Proceedings in Energy, 547–53. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-30171-1_58.

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Krohn, David. "Catalyzing Growth: An Overview of the United Kingdom's Burgeoning Marine Energy Industry". In Transition to Renewable Energy Systems, 351–79. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527673872.ch19.

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Landing, William M., e Brent L. Lewis. "Collection, Processing, and Analysis of Marine Particulate and Colloidal Material for Transition Metals". In Marine Particles: Analysis and Characterization, 263–72. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm063p0263.

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Pattyn, Frank, Ann Huyghe, Sang De Brabander e Bert De Smedt. "Role of Transition Zones in Marine Ice Sheet Dynamics". In Collected Reprint Series, 1–10. Washington, DC: American Geophysical Union, 2014. http://dx.doi.org/10.1002/9781118782033.ch20.

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Corigliano, P., L. Calabrese e V. Crupi. "Salt spray fog ageing of Al/Steel structural transition joints for shipbuilding". In Sustainable Development and Innovations in Marine Technologies, 103–8. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003358961-14.

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Atti di convegni sul tema "Transition marine à continentale"

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Westgate, Z. J., R. D. Beemer e D. J. DeGroot. "Implications of Glauconite Sands on US Offshore Wind Development". In Innovative Geotechnologies for Energy Transition. Society for Underwater Technology, 2023. http://dx.doi.org/10.3723/unfk6402.

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Glauconite is a high specific gravity, greenish black iron-potassium pellet found in shallow marine depositional environments along the US Atlantic Continental Shelf in areas associated with offshore wind developments. Glauconite affects the geotechnical properties of sediments in which it forms and poses risks to foundation installation and performance due to its transformation from a coarse-grained to a fine-grained material due to crushing. Dense, authigenic deposits exhibit less compressibility than other crushable soils, but degrade rapidly under loading due their high internal porosity, linked to their maturity. In situ cone penetrometer testing results exhibit high tip resistance, high sleeve friction, and positive or negative excess pore pressures depending on microstructure, hindering site characterisation using standard soil classification charts. Examples of high glauconite content (> 90% by weight) sand behaviour from onshore deposits along the Atlantic coast are presented, as part of the Joint Industry Project: Piling in Glauconitic Sands (PIGS). Soil properties are shown to be highly sensitive to initial specimen conditions and preparation method, affecting particle size distribution, plasticity and thixotropy, and shear strength. Its implications on offshore geotechnical site investigation and pile foundation design are discussed.
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Apotrosoaei, V. A., M. Munteanu e D. R. Roban. "Marine to Continental Sedimentary Environment Transition at the Paleogene-Miocene Boundary, South Carpathians Foreland". In 75th EAGE Conference and Exhibition incorporating SPE EUROPEC 2013. Netherlands: EAGE Publications BV, 2013. http://dx.doi.org/10.3997/2214-4609.20131079.

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Starratt, Scott W., Jason Addison, Summer Praetorius, David Bukry e Bruce P. Finney. "GULF OF ALASKA CONTINENTAL SHELF – A COMPLICATED GLACIAL TO MARINE TRANSITION IN THE LATE QUATERNARY". In GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-383317.

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Andeskie, Anna Sofia, e Kathleen C. Benison. "THE PERMIAN HUTCHINSON SALT MEMBER OF KANSAS: MARINE, CONTINENTAL, OR TRANSITIONAL?" In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-322518.

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Xu, Lifu. "Characteristics and effectiveness evaluation method of marine continental transitional shale reservoir". In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.6961.

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Hu, Xiao, Yiqun Zhang, Xiaoya Wu, Haizhu Wang e Xu Cui. "A Study on the CO2 Jet Erosion Natural Gas Hydrate with the Influence of Temperature and Confining Pressure". In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0463.

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ABSTRACT Natural gas hydrate (NGH) has been regarded as important potential energy resource. CO2 jet erosion HBS can be combined with Radial Jet Drilling (RJD) technology to achieve high efficiency and low-cost gas hydrate mining. The replacement of CO2 hydrate and CH4 hydrate can also be used to form a stable cap layer on the hydrate reservoir to achieve CO2 storage. In this study, the Arbitrary Lagrangian Euler (ALE) method is used to establish a heat-liquid-solid coupling model for water/CO2 jet erosion HBS, and the CO2 phase change is considered. The influence of different temperature and pressure on jet erosion effect was studied. The results indicate that confining pressure has an inhibitory effect on jet erosion ability, which gradually weakens as the confining pressure increases from 5-10MPa. At confining pressures ranging from 0.1-2.5MPa, the erosion volume decreases with rising temperature due to the gaseous CO2 in the submerged environment, resulting in reduced resistance. The erosion effect is influenced by the characteristics of the jet. At 2.5-5MPa, the CO2 in the submerged environment undergoes a phase transition from gaseous to liquid. At 5-10MPa, the erosion volume increases with temperature due to the liquid CO2 in the submerged environment, resulting in relatively higher resistance. The erosion effect is affected by the fluid in the submerged environment. Additionally, under equivalent temperature and pressure conditions, CO2 jet exhibits superior erosion effectiveness compared to water jet. This study can provide theoretical basis and technical ideas for using RJD technology to mine hydrate and achieve "carbon peak and carbon neutrality". INTRODUCTION Natural gas hydrate is a kind of clean energy with great potential (Sloan, 2003). It is commonly found in marine sediments and permafrost at continental margins, especially in marine sediments (Chong et al., 2016; Michael et al., 2019). The global amount of organic carbon in NGH is twice that of fossil fuels combined (Yu et al., 2019; P. Zhang et al., 2021). So far, many countries in the world have successively formulated the exploitation plan of gas hydrate (Xiao & Zhang, 2021). It can be predicted that the research and exploitation of NGH will remain the focus of global attention for a long time in the future.
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Wang, Zhuangsen. "Sedimentary control and reservoir response of marine continental transitional shale: Taking the eastern margin of Ordos Basin as an example in China". In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4978.

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Maurya, V., S. Fontes e E. La Terra. "An Enhanced and Effective Technique for Demarcation of Continental – Oceanic Transition - Application for South Atlantic Conjugate Margins". In 79th EAGE Conference and Exhibition 2017. Netherlands: EAGE Publications BV, 2017. http://dx.doi.org/10.3997/2214-4609.201701310.

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Bashkeev, A. S., Y. A. Davidenko, K. V. Abornev, S. V. Bukhalov e S. V. Iakovlev. "Some Technological Aspects of Start-Stop Electromagnetic Soundings in the Transition Zone of the Shelf". In Marine Technologies 2019. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201901818.

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Feng, X., F. Liu e J. H. Geng. "A Multi-Criteria Evaluation Framework for Gas Extractability of Marine Hydrate Reservoirs". In Innovative Geotechnologies for Energy Transition. Society for Underwater Technology, 2023. http://dx.doi.org/10.3723/ygxs2307.

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Natural gas hydrates represent a promising clean energy source, and extensive research activities are being carried out worldwide. The selection of previous production trial sites was primarily based on resource size and techno-economic feasibility. To screen out preferred sites for commercial exploitation, broader environmental impacts must be considered. This study proposes a multi-criteria framework for evaluating gas extractability from marine hydrate reservoirs, which integrates both economic benefits and environmental impacts. The economic factors include gas-in-place resources and output yield from depressurization, while the environmental factors encompass assessing risks at both local (borehole instability) and regional (submarine landslides) scales. To quantify the extractability, the framework combines the Analytic Hierarchy Process (AHP) and Fuzzy Synthetic Evaluation method (FSE) by assigning the weight of each factor and determining the membership function. The weighted averages are then calculated and compared to identify the target site. The proposed framework is preliminarily applied to evaluate the candidate site GMGS3-W17 at Shenhu area, South China Sea. Evaluations compared various weightings, indicating a preference for thick burial and high saturation to prioritize revenue dominance, while deep water, low saturation and permeability were prioritized for safety. The results highlight the trade-off between economic and environmental factors in evaluation. The proposed metrics and procedure provide decision support for site selection in the development of marine hydrates.
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Rapporti di organizzazioni sul tema "Transition marine à continentale"

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Lucking, S. K. The Enduring Mission of the Marine Corps Military Transition. Fort Belvoir, VA: Defense Technical Information Center, febbraio 2009. http://dx.doi.org/10.21236/ada508043.

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Forkin, Keith A. Proactive Marine Corps Transition Assistance In The Twenty-First Century. Fort Belvoir, VA: Defense Technical Information Center, febbraio 2015. http://dx.doi.org/10.21236/ada620284.

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Paradis, S., G. J. Simandl, N. Drage, R J D'Souza, D. J. Kontak e Z. Waller. Carbonate-hosted deposits (Mississippi Valley-type, magnesite, and REE-F-Ba) of the southeastern Canadian Cordillera: a review and isotopic data comparison. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/327995.

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The Mississippi Valley-type, magnesite, and REE-F-Ba deposits in the southeastern Canadian Cordillera are in the weakly deformed/metamorphosed Paleozoic carbonate platform of the Rocky Mountains. Most are hosted in dolostones of the middle Cambrian Cathedral, upper Cambrian Jubilee, and Upper Devonian Palliser formations and spatially associated with hydrothermal dolomite. They occur along structurally controlled facies transitions between the shallow-water carbonate platform and deeper water basin rocks of the Paleozoic continental margin. Their location and morphology reflect episodic rifting along the Paleozoic margin. The carbonate protolith was replaced by fine-grained 'replacive dolomite' followed by several stages of coarser saccharoidal, sparry, and saddle dolomites and sulfides replacing dolostone and filling open spaces. The 87Sr/86Sr, delta-18O, delta-13C, and fluid-inclusion data are consistent with high-temperature fluids interacting with host rocks and show influence of adjacent or underlying siliciclastic rocks. The large range of delta-34S values of sulfides suggests that thermochemical sulfate reduction of seawater sulfate was the main sulfur-reducing process, but bacterial sulfate reduction also occurred locally. Lead isotopes suggest a mixing trend involving highly radiogenic and non-radiogenic end members. These observations are consistent with hydrothermal fluids replacing protoliths, precipitating sulfides, and possibly REE-F-Ba mineralization.
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Greenhill, Lucy, Christopher Leakey e Dani Diz. Workshop report: Driving the transition to a resilient and inclusive future: the role of the ocean and policy coherence. Marine Alliance for Science and Technology for Scotland (MASTS), aprile 2021. http://dx.doi.org/10.15664/10023.23456.

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Through a programme of activities from January to July 2021, this Scottish Universities Insight Institute (SUII) project seeks to accelerate progress towards the ‘Just Transition’ for an environmentally sustainable, resilient and equitable economy and society in Scotland, within the framework provided by the UN Sustainable Development Goals (SDGs). The programme aims to: 1. Develop our understanding of interdependencies between marine and cross-cutting policy themes to promote policy coherence, promoting synergies and managing trade-offs. 2. Mobilise the science and policy communities in co-developing knowledge for policy impact, including understanding data and evidence needs for innovation and measuring progress.
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Greenhill, Lucy. MASTS ‘Brexit’ event – summary report. Marine Alliance for Science and Technology for Scotland (MASTS), 2017. http://dx.doi.org/10.15664/10023.25094.

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Background. As negotiations continue in relation to the UK’s departure from the European Union, considerable uncertainty remains around the final structure of any deal and the implications across all policy areas. Maritime issues are of key concern in Scotland and numerous reports and opinions are accumulating, highlighting significant areas of concern, ranging from fisheries to decommissioning, and some potential opportunities. There is a critical need for knowledge and capacity to support and influence the on-going negotiation process, at both the Scottish and UK level. Expertise regarding the broad range of marine research, operations and commerce is in demand to support discussion, promote interests and secure advances where possible. Such discussion must be based on the best available science but taking into account the socio-economic and historical context. The Marine Alliance for Science and Technology for Scotland1 (MASTS) is supporting this discussion, providing scientific expertise and promoting the development of emerging policy and progress towards sustainable marine management, during the transition period and for the post-departure UK organisation. This workshop, supported by MASTS, brought government and academia together to consider the legal, governmental and research framework under which Brexit is taking place and to identify priority areas and activities where information can be shared and options considered for enhancing scientific support for the Brexit process. The objectives were to: • Understand current status of Brexit with respect to marine systems and research capacity, including the legislative framework • Identify the priority gaps in knowledge • Develop ways to enhance communication pathways for the best scientific advice required to support the Brexit process.
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Correia, V., R. A. Fensome, R. A. MacRae, L. T. Dafoe e G. L. Williams. Mesozoic event-stratigraphy of the Scotian Margin, offshore Nova Scotia: preliminary palynological results from the Upper Member of the Missisauga Formation in Panuke B-90. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331910.

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Conceived as a continuation of the previous multidisciplinary event stratigraphy studies of the Late Cretaceous to Neogene of the Scotian Margin in the 2000s, the "Mesozoic eventstratigraphy of the Scotian Margin" project proposes a similar study for the Late Triassic to Early Cretaceous interval. The first stage of this project comprises a detailed multidisciplinary study of the composite Lower Cretaceous section from Panuke B-90 and Cohasset A-52 conventional cores. The present work reports initial palynologic data from the formal Upper Member of the Missisauga Formation in Panuke B-90. These data, combined with preliminary insights from sedimentary facies, macrofossil, and trace fossil analyses, suggest that from the base of the studied section upwards involves a transition from a neritic/shelfal to a mainly estuarine-brackish setting. This was followed by a transgressive cycle through the Upper Member of the Missisauga Formation, which culminated in a return of more fully marine environments near the base of the overlying Naskapi Member of the Logan Canyon Formation. It is apparent that this transgression is not continuous, but intercalated with smaller cycles, well documented by the fluctuations in dominance between terrestrial (pollen and spore abundance) versus marine (mainly dinoflagellate-cyst abundance and richness) palynomorph trends through this succession, presented here in three main intervals. The dinoflagellate-cyst assemblages and key bioevents recorded in this initial study indicate a Barremian age for the Upper Member of the Missisauga Formation in Panuke B-90. The overlying Naskapi Member is expected to be of early Aptian age based on previous reports of the presence of the age-diagnostic ammonite Deshayesites sp. Ongoing work on the conventional cores from Panuke B-90, and subsequently Cohasset A-52 and other wells, will contribute to a comprehensive Mesozoic event-stratigraphic framework for the Scotian Margin.
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Cossarini, Gianpiero. Results of the BGC data assimilation. EuroSea, 2023. http://dx.doi.org/10.3289/eurosea_d4.10.

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This document presents the results of simulations that include glider profiles assimilation. Simulations are performed with the Marine Copernicus operational biogeochemical model system of the Mediterranean Sea. The deliverable shows that the assimilation of BGC-glider is feasible in the contest of biogeochemical operational systems and that it is built upon the experience of BGC-Argo float data assimilation. Different configuration of the assimilation of glider data have been tested to assess the impact of the physical and biogeochemical glider observations. The deliverable also describes the pre-processing activities of the BGC-glider data to provide qualified observations for the data assimilation and the cross validation of chlorophyll glider data with other sensors (ocean colour and BGC-Argo floats). Results of the simulations show that BGC-glider data assimilation, as already shown for BGC-Argo floats, provides complementary information with respect to Ocean Colour data (which is the only or the most commonly assimilated data in biogeochemical operational systems). Beside their relatively limited horizontal spatial impact, the assimilation of BGC profiles can constrain model simulations for relevant biogeochemical processes in specific periods (summer and transition periods) and layers (surface and subsurface). Results also highlight the importance of the assimilation modelling systems that can efficiently resolve the inconsistencies between chlorophyll observations of different sensors. (EuroSea Deliverable ; D4.10)
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Jalkanen, Jukka-Pekka, Erik Fridell, Jaakko Kukkonen, Jana Moldanova, Leonidas Ntziachristos, Achilleas Grigoriadis, Maria Moustaka et al. Environmental impacts of exhaust gas cleaning systems in the Baltic Sea, North Sea, and the Mediterranean Sea area. Finnish Meteorological Institute, 2024. http://dx.doi.org/10.35614/isbn.9789523361898.

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Description: Shipping is responsible for a range of different pressures affecting air quality, climate, and the marine environment. Most social and economic analyses of shipping have focused on air pollution assessment and how shipping may impact climate change and human health. This risks that policies may be biased towards air pollution and climate change, whilst impacts on the marine environment are not as well known. One example is the sulfur regulation introduced in January 2020, which requires shipowners to use a compliant fuel with a sulfur content of 0.5% (0.1% in SECA regions) or use alternative compliance options (Exhaust Gas Cleaning Systems, EGCS) that are effective in reducing sulfur oxide (SOx) emissions to the atmosphere. The EGCS cleaning process results in large volumes of discharged water that includes a wide range of contaminants. Although regulations target SOx removal, other pollutants such as polycyclic aromatic hydrocarbons (PAHs), metals and combustion particles are removed from the exhaust to the wash water and subsequently discharged to the marine environment. Based on dilution series of the Whole Effluent Testing (WET), the impact of the EGCS effluent on marine invertebrate species and on phytoplankton was found to vary between taxonomic groups, and between different stages of the invertebrate life cycle. Invertebrates were more affected than phytoplankton, and the most sensitive endpoint detected in the present project was the fertilisation of sea urchin eggs, which were negatively affected at a sample dilution of 1 : 1,000,000. Dilutions of 1: 100,000 were harmful to early development of several of the tested species, including mussels, polychaetes, and crustaceans. The observed effects at these low concentrations of EGCS effluent were reduced egg production, and deformations and abnormal development of the larvae of the species. The ecotoxicological data produced in the EMERGE project were used to derive Predicted No Effect Concentration values. Corresponding modelling studies revealed that the EGCS effluent can be considered as a single entity for 2-10 days from the time of discharge, depending on the environmental conditions like sea currents, winds, and temperature. Area 10-30 km outside the shipping lanes will be prone to contaminant concentrations corresponding to 1 : 1,000,000 dilution which was deemed harmful for most sensitive endpoints of WET experiments. Studies for the Saronikos Gulf (Aegean Sea) revealed that the EGCS effluent dilution rate exceeded the 1 : 1,000,000 ratio 70% of the time at a distance of about 10 km from the port. This was also observed for 15% of the time within a band of 10 km wide along the shipping lane extending 500 km away from the port of Piraeus. When mortality of adult specimens of one of the species (copepod Acartia tonsa) was used as an endpoint it was found to be 3-4 orders of magnitude less sensitive to EGCS effluent than early life stage endpoints like fertilisation of eggs and larval development. Mortality of Acartia tonsa is commonly used in standard protocols for ecotoxicological studies, but our data hence shows that it seriously underestimates the ecologically relevant toxicity of the effluent. The same is true for two other commonly used and recommended endpoints, phytoplankton growth and inhibition of bioluminescence in marine bacteria. Significant toxic effects were reached only after addition of 20-40% effluent. A marine environmental risk assessment was performed for the Öresund region for baseline year 2018, where Predicted Environmental Concentrations (PECs) of open loop effluent discharge water were compared to the PNEC value. The results showed modelled concentrations of open loop effluent in large areas to be two to three orders of magnitude higher than the derived PNEC value, yielding a Risk Characterisation Ratio of 500-5000, which indicates significant environmental risk. Further, it should be noted that between 2018-2022 the number of EGCS vessels more than quadrupled in the area from 178 to 781. In this work, the EGCS discharges of the fleet in the Baltic Sea, North Sea, the English Channel, and the Mediterranean Sea area were studied in detail. The assessments of impacts described in this document were performed using a baseline year 2018 and future scenarios. These were made for the year 2050, based on different projections of transport volumes, also considering the fuel efficiency requirements and ship size developments. From the eight scenarios developed, two extremes were chosen for impact studies which illustrate the differences between a very high EGCS usage and a future without the need for EGCS while still compliant to IMO initial GHG strategy. The scenario without EGCS leads to 50% reduction of GHG emissions using low sulfur fuels, LNG, and methanol. For the high EGCS adoption scenario in 2050, about a third of the fleet sailing the studied sea areas would use EGCS and effluent discharge volumes would be increased tenfold for the Baltic Sea and hundredfold for the Mediterranean Sea when compared to 2018 baseline discharges. Some of the tested species, mainly the copepods, have a central position in pelagic food webs as they feed on phytoplankton and are themselves the main staple food for most fish larvae and for some species of adult fish, e.g., herring. The direct effect of the EGSE on invertebrates will therefore have an important indirect effect on the fish feeding on them. Effects are greatest in and near shipping lanes. Many important shipping lanes run close to shore and archipelago areas, and this also puts the sensitive shallow water coastal ecosystems at risk. It should be noted that no studies on sub-lethal effects of early 19 life stages in fish were included in the EMERGE project, nor are there any available data on this in the scientific literature. The direct toxic effects on fish at the expected concentrations of EGCS effluent are therefore largely unknown. According to the regional modelling studies, some of the contaminants will end up in sediments along the coastlines and archipelagos. The documentation of the complex chemical composition of EGCS effluent is in sharp contrast to the present legislation on threshold levels for content in EGCS effluent discharged from ships, which includes but a few PAHs, pH, and turbidity. Traditional assessments of PAHs in environmental and marine samples focus only on the U.S. Environmental Protection Agency (EPA) list of 16 priority PAHs, which includes only parent PAHs. Considering the complex PAHs assemblages and the importance of other related compounds, it is important to extend the EPA list to include alkyl-PAHs to obtain a representative monitoring of EGCS effluent and to assess the impact of its discharges into the marine environment. An economic evaluation of the installation and operational costs of EGCS was conducted noting the historical fuel price differences of high and low sulfur fuels. Equipment types, installation dates and annual fuel consumption from global simulations indicated that 51% of the global EGCS fleet had already reached break-even by the end of 2022, resulting in a summarised profit of 4.7 billion €2019. Within five years after the initial installation, more than 95% of the ships with open loop EGCS reach break-even. The pollutant loads from shipping come both through atmospheric deposition and direct discharges. This underlines the need of minimising the release of contaminants by using fuels which reduce the air emissions of harmful components without creating new pollution loads through discharges. Continued use of EGCS and high sulfur fossil fuels will delay the transition to more sustainable options. The investments made on EGCS enable ships to continue using fossil fuels instead of transitioning away from them as soon as possible as agreed in the 2023 Dubai Climate Change conference. Continued carriage of residual fuels also increases the risk of dire environmental consequences whenever accidental releases of oil to the sea occur.
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Lindfors, Axel, e Roozbeh Feiz. The current Nordic biogas and biofertilizer potential: An inventory of established feedstock and current technology. Linköping University Electronic Press, maggio 2023. http://dx.doi.org/10.3384/9789180752558.

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Abstract (sommario):
Biogas solutions in the Nordics is undergoing rapid developments and the demand for biogas is ever increasing because of the Russian war on Ukraine and the transition to fossil free industry and transportation. Furthermore, with the introduction of several multi-national companies into the biogas sector in the Nordics and with more and more biomethane being traded across national borders, it becomes increasingly important to view biogas solutions in the Nordics as a whole and to go beyond the confines of each individual nation. Since the transition and the current energy crisis require a quick response, understanding what could be done with current technologies and established substrates is important to guide decision-making in the short-term. This study aims to do just that by presenting the current biogas potential for the Nordics, including Denmark, Finland, Iceland, Norway, and Sweden. The potential was estimated for eight categories: food waste, manure, food industry waste, sludge from wastewater treatment, landscaping waste, straw, agricultural residues, and crops with negligible indirect land use effects (such as ley crops and intermediary crops). Two categories were excluded due to a lack of appropriate estimation procedures and time to develop such procedures, and these were marine substrates and forest industry waste. Furthermore, several categories are somewhat incomplete due to lack of data on the availability of substrates and their biogas characteristics. These include, for example, crops grown on Ecological focus areas, excess ley silage, damaged crops, and certain types of food industries. The specifics of each category is further detailed in Section 2 of the report. In the report, the biogas potential includes the biomethane potential, the nutrient potential, and the carbon dioxide production potential, capturing all outputs of a biogas plant. The results of the potential study show that the current biomethane potential for the Nordics is about 39 TWh (140 PJ) per year when considering the included biomass categories in the short-term perspective. In relation to current production, realizing this potential would mean a roughly fourfold increase in yearly production, meaning that a significant unexploited potential remains. On the nutrient side, the biogas system in the Nordics would, given the realization of the estimated potential, be of roughly the same size as current mineral fertilizer use (about 75 percent for nitrogen and 160 percent for phosphorous). While this represents the management of a significant portion of nutrients used in agriculture, the potential to replace or reduce mineral fertilizer use through biogas expansion remains unexplored in this study since a significant portion of nutrients come from biomass that is already used as fertilizer (e.g., manure). Finally, on the carbon dioxide side, about 4.2 million tonnes of carbon dioxide would be produced, which could be either captured and stored or captured and utilized, thereby further increasing the positive environmental effects associated with biogas solutions. In conclusion, there remains a large unexploited biogas potential in the Nordics, even when only considering current technologies and established feedstock that could be realized in the short-term (the theoretical potential is much larger since many substrate categories are excluded and the potential is limited to established technologies). Such a realization would bring large increases to biomethane production but would also mean that a significant amount of nutrients would be recirculated through the biogas system. This means that the biogas system has a key role to play in increasing both the food and energy security in the Nordic countries, in addition to its many positive environmental effects.
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10

Sprague, Joshua, David Kushner, James Grunden, Jamie McClain, Benjamin Grime e Cullen Molitor. Channel Islands National Park Kelp Forest Monitoring Program: Annual report 2014. National Park Service, agosto 2022. http://dx.doi.org/10.36967/2293855.

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Abstract (sommario):
Channel Islands National Park (CHIS) has conducted long-term ecological monitoring of the kelp forests around San Miguel, Santa Rosa, Santa Cruz, Anacapa and Santa Barbara Islands since 1982. The original permanent transects were established at 16 sites between 1981 and 1986 with the first sampling beginning in 1982, this being the 33rd year of monitoring. An additional site, Miracle Mile, was established at San Miguel Island in 2001 by a commercial fisherman with assistance from the park. Miracle Mile was partially monitored from 2002 to 2004, and then fully monitored (using all KFM protocols) since 2005. In 2005, 16 additional permanent sites were established to collect baseline data from inside and adjacent to four marine reserves that were established in 2003. Sampling results from all 33 sites mentioned above are included in this report. Funding for the Kelp Forest Monitoring Program (KFM) in 2014 was provided by the National Park Service (NPS). The 2014 monitoring efforts utilized 49 days of vessel time to conduct 1,040 dives for a total of 1,059 hours of bottom time. Population dynamics of a select list of 71 “indicator species” (consisting of taxa or categories of algae, fish, and invertebrates) were measured at the 33 permanent sites. In addition, population dynamics were measured for all additional species of fish observed at the sites during the roving diver fish count. Survey techniques follow the CHIS Kelp Forest Monitoring Protocol Handbook (Davis et al. 1997) and an update to the sampling protocol handbook currently being developed (Kushner and Sprague, in progress). The techniques utilize SCUBA and surface-supplied-air to conduct the following monitoring protocols: 1 m2 quadrats, 5 m2 quadrats, band transects, random point contacts, fish transects, roving diver fish counts, video transects, size frequency measurements, and artificial recruitment modules. Hourly temperature data were collected using remote temperature loggers at 32 sites, the exception being Miracle Mile where there is no temperature logger installed. This annual report contains a brief description of each site including any notable observations or anomalies, a summary of methods used, and monitoring results for 2014. All the data collected during 2014 can be found in the appendices and in an Excel workbook on the NPS Integrated Resource Management Applications (IRMA) portal. In the 2013 annual report (Sprague et al. 2020) several changes were made to the appendices. Previously, annual report density and percent cover data tables only included the current year’s data. Now, density and percent cover data are presented in graphical format and include all years of available monitoring data. Roving diver fish count (RDFC), fish size frequency, natural habitat size frequency, and Artificial Recruitment Module (ARM) size frequency data are now stored on IRMA at https://irma.nps.gov/DataStore/Reference/Profile/2259651. The temperature data graphs in Appendix L include the same graphs that were used in past reports, but include additional violin plot sections that compare monthly means from the current year to past years. In addition to the changes listed above, the layout of the discussion section was reordered by species instead of by site. The status of kelp forests differed among the five park islands. This is a result of a combination of factors including but not limited to, oceanography, biogeography and associated differences in species abundance and composition, as well as sport and commercial fishing pressure. All 33 permanent sites were established in areas that had or were historically known to have had kelp forests in the past. In 2014, 15 of the 33 sites monitored were characterized as developing kelp forest, kelp forest or mature kelp forest. In addition, three sites were in a state of transition. Two sites were part kelp forest and part dominated by Strongylocentrotus purpuratus...
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