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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Évolution spatio-temporelle des déformations sismiques tardi-Pleistocènes et Holocènes dans le massif du Gobi-Altaï, Mongolie : approches morphotectonique et paléosismologique / Spatio-temporal evolution of late-Pleistocene - Holocène seismic deformations through the Gobi-Altai mountain range : morphotectonical and paleosesmological approaches

Kurtz, Robin 24 November 2017 (has links)
La Mongolie occidentale a connu une sismicité intracontinentale exceptionnelle au cours de la première moitié du XXe siècle, avec 4 évènements sismiques d'une magnitude supérieure à 7.9, localisés sur des grandes structures décrochantes en régime transpressif senestre. Cette sismicité historique a été qualifiée d’essaim sismique, et des études paléosismologiques indiquent que ce phénomène a déjà pu se produire par le passé (3 à 4 ka). Mais si la partie est de la chaine du Gobi-Altaï a rompu lors du séisme du même nom en 1957 (Mw8) le long de la faille de Bogd orientale (WBF), plusieurs traces de failles affectant des formations Holocènes et présentant des longueurs > 100 km ont été documentées dans la partie ouest du massif, sans pour autant faire l’objet d’études quantitatives.Cette thèse apporte un état des lieux de l’activité sismique dans le Gobi-Altaï, au travers d’une cartographie détaillée des escarpements de failles actives au cours du pléistocène supérieur, associée à une analyse de la segmentation au regard de critères géométriques et cinématiques. Parallèlement, des investigations morphotectoniques et paléosismologiques, couplées à des méthodes de datations au 10Be in situ, OSL et 14C, ont permis de quantifier les vitesses de glissement depuis le Pléistocène supérieur, et les âges des paléo-ruptures au cours de l’Holocène sur les deux principaux décrochements analysés : les failles de la Vallée des Lacs (VOLF), et de Bogd occidentale (WBF) ; des données préliminaires permettent également de contraindre l’âge de la dernière rupture et la vitesse de glissement sur les failles de Tsogt (TF) et de Tsagaan Gol (TGF), situées respectivement dans le prolongement occidental de la WBF et de la VOLF. De plus, des mesures systématiques des décalages cosismiques horizontaux enregistrés par la morphologie, notamment le long de la rupture de surface du séisme de 1957, couplés à l’utilisation et le développement d’une approche statistique de détermination des glissements cosismiques moyens au regard de la segmentation, a permis de déterminer la fonction de distribution du glissement le long de l’EBF sur 3 cycles sismiques, suggérant d’une part une distribution du glissement assez homogène le long de la rupture, et d’autre part que le glissement du séisme généré en 1957 est d’une amplitude comparable de celle des précédents séismes, pour au moins 50 % de la rupture principale. Cette approche de détermination statistique des glissements moyens sur plusieurs cycles sismiques est prometteuse mais présente néanmoins certaines incohérences, et des voies de développement et de validations sont proposées.Les paramètres morphotectoniques et les âges des paléoséismes documentés dans cette thèse présentent une grande cohérence avec les données précédemment acquises sur l’EBF, avec des vitesses de faille lentes (0,7 ± 0,2 mm.a-1 sur la WBF et 0,5 ± 0,1 mm.a-1 sur la VOLF), des périodes de retour longues (4,0 ± 1,2 ka pour la WBF), et des décalages cosismiques relativement importants (2 – 4 m). Nos mesures de vitesses de faille indiquent par ailleurs une distribution de la déformation depuis la EBF vers les WBF et VOLF, séparant la déformation en deux faisceaux de failles, l’un se branchant au nord depuis la VOLF sur la TGF. Les déterminations des âges de paléoséismes indiquent une possibilité de cluster entre les différentes failles étudiées, avec trois ruptures potentiellement synchrones au cours de l’Holocène, dont une, rompant l’intégralité des décrochements analysés (WBF, EBF et VOLF), s’avère être temporellement corrélée au précédent cluster potentiellement identifié à 3 – 4 ka. Les paramètres présentés dans cette thèse permettent finalement de calculer des paléomagnitudes associées aux deniers évènements sur les WBF et VOLF, comprises entre Mw7,6 et Mw8 selon les paramètres et les lois considérés. Ces données fondamentales pourront servir de canevas de base pour les actuelles études d’aléas sismique en Mongolie. / Western Mongolia experienced an exceptional intracontinental seismic activity during the first part of the XXth century, with four seismic events with Mw > 7.9, located on large strike-slip faults with a transpressive left-lateral motion. This historical seismicity has been qualified as a cluster, and paleoseismological studies indicate that this phenomenon might have occurred 3 to 4 ka ago. Although the eastern part of the Gobi-Altai mountain range broke during the eponymous earthquake in 1957 (Mw8) along the Eastern Bogd Fault (EBF), several fault traces affecting Holocene formations and presenting continuous fault length > 100 km have been documented on the western part of the range, while not been the purpose of quantitative studies.This thesis first gives an inventory of the seismic activity within the Gobi-Altai, through detailed mapping of the fault scarps which show activity during the late-Pleistocene, also with an analyze of the fault segmentation regarding to geometric and kinematic criteria. Secondly, some morphotectonical and paleoseismological surveys have been carried on, along with dating techniques as 10Be in situ, OSL and radiocarbon, which allow quantifying the faults slip-rates since late-Pleistocene, and paleo-ruptures ages during the Holocene period on the two main strike slip faults analyzed : the Valley of Lakes Fault (VOLF), and the Western Bogd Fault (WBF); preliminary data also allow quantifying the slip rates and the age of the most recent event along the Tsogt Fault (TF) and the Tsagaan Gol fault (TGF), respectively located in the westward continuation of the WBF and the VOLF. Moreover, systematic lateral offset measurements have been carried on along the faults traces, and especially along the 1957 surface rupture, where a statistical approach based on probability density has been applied in order to assess the average lateral offsets successively recorded by the landforms, and reveals that the slip distribution along the EBF on 3 seismic cycles. This suggests first that the slip distributions rather even along the rupture, and secondly that the slip related to the 1957 earthquake is of the same amount than previous major ruptures on that fault, for half of the main 1957 surface rupture. This approach of average coseismic slip assessment on several seismic cycles is promising, but still presents some inconsistencies, and we propose developments and validation perspectives.Morphotectonic parameters and ages of paleo-earthquakes reported in this thesis present a strong consistency with former studies along the EBF, with slow slip-rates (0,7 ± 0,2 mm.yr-1 on the WBF and 0,5 ± 0,1 mm.yr-1 on the VOLF), and significant left lateral coseismic offsets (2 – 4 m). Our measurements of slip rates indicate furthermore a distribution of the on-fault deformation from the EBF to the WBF and the VOLF, splitting the deformation in two branches, the north one reaching the TGF and the southern one visibly branches on the TF. Assessments of the paleoearthquakes ages show three possible clusters between the studied faults during the Holocene time, and one of them may break the three faults (WBF, EBF and VOLF), and seems as well to correspond to the cluster possibly identified 3-4 kyr ago. The fault parameters presented in this thesis allow computing the paleomagnitudes related to last seismic events along the WBF and the VOLF, ranging from Mw7.6 and Mw8, depending of parameters and empirical relations considered. Finally those fundamental data may serve as basic pattern for current seismic hazard assessments in Mongolia.
12

Τεκτονική ανάλυση των ρηξιγενών ζωνών Κατούνας και Αμφιλοχίας

Γκαδρή, Ελισσάβετ 31 May 2012 (has links)
Η μελέτη του αναγλύφου με τη χρήση μορφοτεκτονικών παραμέτρων κατά μήκος ρηξιγενών ζωνών μας δίνει σημαντικές πληροφορίες για την ενεργότητα ή όχι των ζωνών αυτών και επίσης για την κατανόηση των επιφανειακών επιπτώσεων των σεισμών και τη σεισμική επικινδυνότητά τους. Στην παρούσα μεταπτυχιακή διατριβή ειδίκευσης μελετήθηκαν, με τη βοήθεια της μορφοτεκτονικής ανάλυσης, οι ΒΒΔ– διεύθυνσης ρηξιγενείς ζώνες της Κατούνας (ΡΖΚ) και Αμφιλοχίας (ΡΖΑ) στην περιοχή της Αιτωλοακαρνανίας (Δυτ. Ελλάδα). Για τον ποιοτικό και ποσοτικό προσδιορισμό της τεκτονικής ενεργότητας των ΡΖΚ και ΡΖΑ εφαρμόστηκαν διάφοροι μορφοτεκτονικοί δείκτες, όπως ο δείκτης ευθυγράμμισης ορεογραφικού μετώπου (Smf), ο δείκτης λόγου πλάτους προς ύψος κοιλάδας (Vf), ο δείκτης μήκους-κλίσης ρέματος (SL), ο συντελεστής ασυμμετρίας λεκάνης απορροής (AF), ο δείκτης σχήματος λεκάνης απορροής (Bs), και το ποσοστό τριγωνικών γεωμορφών (Pf), οι οποίοι υπολογίστηκαν με τη βοήθεια ψηφιακών μοντέλων εδάφους (DEM). Από την ανάλυση των διαγραμμάτων κατακόρυφης μετατόπισης με το μήκος στις δύο ρηξιγενείς ζώνες φαίνεται ότι αυτές παρουσιάζονται τμηματοποιημένες, ενώ μεγαλύτερη κατακόρυφη μετατόπιση, της τάξης των 750–800m παρουσιάζεται στη ΡΖΑ. Από τη συσχέτιση των δεικτών Smf και Vf, προκύπτει ότι και οι δύο ρηξιγενείς ζώνες είναι ενεργές και συγκεκριμένα ανήκουν στην τάξη 1 της τεκτονικής ενεργότητας, με ρυθμό ανύψωσης μεγαλύτερο από 1mm/yr. Επίσης, από την συσχέτιση των τιμών των δεικτών Vf – Bs – SL προκύπτει ότι η αυξημένη ενεργότητα και για τις δύο ρηξιγενείς ζώνες, συγκεντρώνεται στις περιοχές επικάλυψης και αλληλεπίδρασης των επιμέρους ρηξιγενών τμημάτων. Η ύπαρξη επιμήκων και ασύμμετρων λεκανών απορροής στη βάση των ρηξιγενών ζωνών και η σεισμικότητα κατά μήκος τους επιβεβαιώνει ότι οι ευθύγραμμοι αυτοί ρηξιγενείς πρόποδες είναι τεκτονικά ενεργοί. Τα ποσοστά τριγωνικών γεωμορφών υποδηλώνουν ότι η παραμόρφωση πραγματοποιείται με αργό ρυθμό. Οι ρηξιγενείς ζώνες Κατούνας και Αμφιλοχίας χαρακτηρίζονται από ένα ενδιάμεσο τύπο παραμόρφωσης μεταξύ εφελκυσμού, κάθετα στις ΒΒΔ – διευθυνόμενες ζώνες, και αριστερόστροφης διατμητικής παραμόρφωσης, προσδίδοντας σε αυτές ένα χαρακτήρα ζωνών μεταβίβασης (transfer zone) με διαγώνια διαστολή μεταξύ των ΔΒΔ – διευθυνόμενων τεκτονικών τάφρων του Πατραϊκού και Αμβρακικού κόλπου. / The study of the topographic relief along fault zones using geomorphological indices provides important information about the activity of these zones and understanding of the surface effects of earthquakes and possible seismic risk. In this study, a morphotectonic analysis was applied along the NNW-trending fault zones of Katouna (PZK) and Amfilochia (PZA), which are located in Aitoloakarnania (W. Greece). For the qualitative and quantitative determination of tectonic activity along the PZK and PZA zones several morphotectonic indices were implemented, such as the mountain – front sinuosity index (Smf), the ratio of valley–floor width to valley height (Vf), the stream length–Gradient index (SL), the Basin Asymmetry Factor (AF), the Drainage Basin Shape (Bs), and the percentage of triangular facets along mountain fronts (Pf). All these morphotectonic indices and the drainage basin pattern were calculated using a 30 m Digital Elevation Model (DEM). The distribution of the throw along the fault zones implies that these zones are segmented and consist of several individual fault segments, while the highest throw values, on the order of 750-800m, are located in the central segments of the PZA. The maximum throw in PZK is lower and reaches a value of 250-300m. From the correlation of morphotectonic indices Smf and Vf, it seems that both fault zones are active (class 1 of tectonic activity), with a rate of uplift > 1mm/yr. Furthermore, the correlation of Vf , Bs and SL shows that the highest tectonic uplift and subsequent activity for both fault zones concentrates on the relay zones (overlapping or underlapping) between the interacting fault segments. The presence of long and asymmetric basins on the footwall block of the fault zones and the associated seismicity along them confirms that the segments are tectonically active. The percentage of triangular facets (22-55%) suggests the low rates of deformation along these fault zones and the increased activity of them towards the southern tip zones. The fault zones of Katouna and Amfilochia appear to be characterized by an intermediate type of deformation, showing extensional deformation in a NE-orientation and sinistral shear deformation along their NNW-orientation. The Katouna and Amfilochia fault zones appears to act as a composite transfer zone accommodating left-lateral oblique extension between the more active WNW-directed grabens of Amvrakikos and Gulf of Patras.
13

Estudo do meio físico e caracterização da capacidade de suporte natural da região de Pirassununga/SP / Study of the physical environment and characterization of natural support capacity in the region of Pirassununga/SP

Lima, Meire Mateus de [UNESP] 19 April 2016 (has links)
Submitted by Meire Mateus de Lima (meiresaa@yahoo.com.br) on 2016-06-15T17:09:02Z No. of bitstreams: 1 Dissertacao_Meire_Lima.pdf: 40136639 bytes, checksum: e41d780e6e958ac46d1eda56e59ccdfb (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-16T13:41:52Z (GMT) No. of bitstreams: 1 lima_mm_me_rcla.pdf: 40136639 bytes, checksum: e41d780e6e958ac46d1eda56e59ccdfb (MD5) / Made available in DSpace on 2016-06-16T13:41:52Z (GMT). No. of bitstreams: 1 lima_mm_me_rcla.pdf: 40136639 bytes, checksum: e41d780e6e958ac46d1eda56e59ccdfb (MD5) Previous issue date: 2016-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os crescentes usos e ocupação do meio e utilização dos recursos naturais têm mostrado a necessidade do desenvolvimento de estudos integrados dirigidos a uma adequação das atividades do homem com a capacidade de suporte natural do meio físico. Desta forma, este projeto objetiva, para a região de Pirassununga, localizada no centro-nordeste paulista, aplicar um procedimento metodológico que auxilie a compartimentação do meio físico, mediante o uso de geotecnologias e aspectos geodinâmicos, visando o planejamento do uso e ocupação da terra, com fins de definir a suscetibilidade natural à erosão e a capacidade de suporte natural do meio. Tais informações poderão ser utilizadas pelos produtores rurais e órgãos públicos no intuito de orientar a tomada de decisões quanto às medidas de controle para os problemas ambientais encontrados, para a recuperação de áreas impactadas, bem como orientações para o uso e ocupação sustentável da terra, reduzindo os impactos negativos. Com base nos resultados das análises de drenagem, do relevo, morfoestrutural, morfotectônica e da evolução paleoambiental (isobases confluentes) nota-se que a região apresenta uma grande densidade de drenagem, variação altimétrica e de classes de declividade, assim como um intenso fraturamento, o que gera paisagens de abatimento e soerguimento de blocos (horsts e grabens), altos e baixos estruturais deformados e altos e baixos topográficos intercalados, exigindo, deste modo, indicações de manejo específicos para cada área. A análise da evolução da paisagem, por meio das isobases confluentes, contribui ainda para melhor definir o fraturamento regional e o domínio de processos colúvio-aluvionares, formadores das associações de solos. A integração dos diversos temas desenvolvidos neste trabalho possibilitou a geração das cartas temáticas de suscetibilidade natural à erosão, indicação de áreas para preservação ambiental e áreas para destinação dos resíduos antrópicos, sólidos e líquidos, buscando a classificação mais adequada da capacidade de suporte natural da área. A partir dos resultados constatou-se que na região de Pirassununga predominam as suscetibilidades naturais à erosão baixas e moderadas, assim como uma alta capacidade de suporte natural, acompanhando as planícies de inundação atual/subatual e os planaltos muito baixos a médios. Merecendo atenção especial a porção leste da área, por apresentar capacidade de suporte predominantemente moderada e a porção oeste, por apresentar capacidades de suporte de moderadas a muito baixas, podendo ser utilizadas de forma restrita, requerendo, todavia, estudos mais específicos para melhor dirigir tal ocupação. Considerando ainda que, com a aplicação de técnicas inadequadas de uso, manejo do solo e disposição de resíduos, a suscetibilidade natural à erosão pode aumentar significativamente e, a capacidade de suporte natural do meio ambiente ficar comprometida. Desta forma, recomenda-se que os manejos, considerando as peculiaridades de cada local individualmente, sejam definidos em função das recomendações de profissionais capacitados em cada atividade, diminuindo assim os problemas para o uso e ocupação do meio físico da região. / The increasing use and occupation of the environment and utilization of the natural resources has presented the need for the development of integrated studies driven towards an adaptation of the activities performed by people with natural support for the physical environment. This way, this project has the objective, for a region of Pirassununga, located in the center northeast of São Paulo, to apply a methodological procedure that aids the partitioning of the physical environment, with the use of geotechnologies and geodynamic aspects, seeking the planning of the soil occupation use, to define the natural susceptibility to the erosions and the capacity of natural environment support. Such information can be utilized by farmers and public agencies in the intent orientate the decision making of the control measures for the environmental problems found, for the recovery of impacted areas, as well as in orientating for sustainable soil occupation use, reducing the negative impacts. With basis on the analysis results of drainage, relief, morphostructural, morphotectonic and the paleoenvironmental (confluent isobases), it is noticed that the region presents a great density of drainage , altimetry variation and gradient classes, as well as intense fracturing, which generates a landscape of abatement and uplift of blocks (horst and grabens), high and low structural deformation and high and low interleaved topographic, demanding, in this way, specific handling indications for each area. The landscape evolution analysis, by confluent isobases, contributes to better define the regional fracturing and the command of colluvium-alluvial processes, makers of the soil association. The integration of the various developed themes in this work enabled the creation of themed letters for natural susceptibility to erosions, indication of environmental preservation areas and areas for anthropic residue destination, solid and liquid, seeking the more adequate classification of the natural support of the capacity for the area. With the results, it was found that in the region of Pirassununga prevails the natural susceptibility to low and moderate erosions, as well as high capacity for natural support, following the current and not so current flood plains and the very low to medium plateaus. Deserving special attention to the east portion of the area for presenting support capacity mainly moderate and the west portion for presenting a moderate to very low support capacity, being able to be utilized in a restrict manner, requiring, however, more specific studies to better drive such occupation. Considering that, with the application of inadequate techniques of use, soil handling and residue disposal, the natural susceptibility to erosions can increase significantly and the natural support capacity of the environment can become compromised. This way, it is recommended that handling, considering the peculiarities of each individual location, be defined due to recommendation of capacitated professionals in each activity, thus decreasing the problems for the use and occupation of the physical environment of the region.
14

Ambientes de sedimentação continental da planície costeira de Bertioga (SP): evidências geológicas e geomorfológicas de neotectônica / Continental sedimentation environments of the Bertioga coastal plain (SP): neotectonic geological and geomorphological evidence.

Abreu, Marco Henrique Meletti de 16 February 2018 (has links)
A presente pesquisa está inserida nos estudos referentes à evolução quaternária dos ambientes costeiros do litoral do Estado de São Paulo (Brasil). A planície costeira de Bertioga, com extensão de aproximadamente 45 km, largura máxima de apenas 6 km e profundidade de até 100 m na parte central (presença de um hemi-gráben), é um exemplo de evolução morfotectônica e eustática, que resultou numa configuração geológico-geomorfológica complexa (Souza, 2015). Ela reúne todos os tipos de ambientes de sedimentação (Unidades Quaternárias - UQs) comuns em extensas planícies costeiras, a saber: (a) marinho-praial - praias atuais (Pr), cordões litorâneos (LHTb) e terraços marinhos holocênicos (LHTa), e duas gerações de terraços marinhos pleistocênicos baixos (LPTb) e altos (LPTa); (b) estuarino-lagunar e paludial - planícies de maré atuais (LOL) e depressões estuarino-lagunares holocênicas colmatadas, que evoluíram para ambientes paludiais atuais (LCD); (c) fluvial - terraços aluviais, barras fluviais e depósitos de leito e de planície de inundação holocênicos a atuais (LHF) e pleistocênicos (LPF), e planícies de depósitos mistos (aluviais e de colúvios de baixada/corridas de detritos) holocênicos a atuais (LMP). Vários estudos ambientais e que envolvem direta ou indiretamente aspectos sedimentológicos têm sido feitos nessa planície costeira, abordando os seguintes temas principais: mapeamentos geológicos, geomorfológicos e pedológicos, geocronologia, hidrogeologia, neotectônica, fitossociologia e florística (vegetação) e riscos ecológicos. O presente trabalho tem por objetivo apresentar os indicadores morfotectônicos nos depósitos continentais na planície costeira de Bertioga - SP, baseada na análise e compilação de um amplo conjunto de dados disponíveis. Os parâmetros escolhidos foram: diâmetro médio e grau de seleção (em mm e em phi) dos sedimentos, depósitos e solos associados, identificação dos padrões morfotectônicos. Bem como a aplicação de técnicas em Geoprocessamento, para a extração automática da rede de drenagem. De maneira geral, os parâmetros granulométricos das UQs estudadas estão distribuídos da seguinte maneira: diâmetro médio - varia entre silte médio (5.74 fi) até areia grossa (0.33 fi); grau de seleção - varia de muito pobremente selecionado (3.24 fi) até muito bem selecionado (0.30 fi).Em relação aos solos associados nos ambientes fluviais e mistos são, Neossolos Flúvicos, Gleissolos Háplicos e Tiomórficos, Cambissolos Flúvicos e Háplicos. As altimetrias dos depósitos quaternários variam de 0 a 13 m. As características principais de cada UQ são apresentadas a seguir. LHF (altitude: 2-5 m) diâmetro médio entre 3.40-3.10 fi; grau de seleção entre 0.38-0.87 fi; NA entre 0,5-1,2 m; grãos sub-angulosos a sub-arredondados e lisos. LPF (altitude: 7,5-10 m) diâmetro médio entre 4.79-0.32 fi; grau de seleção entre 0.35-3.23 fi; NA entre 0,5-1,5 m; grãos arredondados a sub-arredondados e lisos. LMP (altitude: 5-7 m) diâmetro médio entre 1.08-4.37 fi; grau de seleção entre 1.99-2.41 fi; NA entre 0,2-1,1 m; grãos angulosos a sub-angulosos e lisos. Os resultados obtidos em campo e laboratório são apresentados iniciando-se pela caracterização da área de estudo, através das unidades geológicas quaternárias, que por sua vez são considerados exclusivas para o litoral paulista, justificando o objetivo desta pesquisa, assim, são apresetandos resultados e considerações que procuraram integrar as etapas estudadas. Assim, podemos então entender que são muitos os fatores que puderam ser interpretados a partir dos resultados gerados a partir da análises em geoprocessamento, principalmente ao analisarmos canais fluviais e suas diferentes formas de análise. Nesta etapa procuramos reforçar que as anomalias de drenagem apresentadas, nada mais são do que fortes indicadores tectônicos ou neotectônicos, quando usamos a abordagem sedimentar, no período quaternário, reforçando como a visão da paisagem, vista pela geografia demonstra uma dinâmica ilustrativa,procurando facilitar as metodologias de análises do ambiente. As evidências granulométricas das alternâncias de energia dos agentes de transporte, águas fluviais e pluviais, promoveram o deslocamento e a deposição dos sedimentos, corroborando para a delimitar espacialmente essas unidades geológicas. Com as expedições em campo, foi possível identificar, antigos leitos de canais de rios em diversos setores da planície. Sequencias de camadas de sedimentos arenosos, nas frações areias grossas e muito grossas, intercalados com grânulos e alguns fragmentos de madeira, identificados nas coletas dos sedimentos em laboratório, evidenciaram o traçado dos antigos terraços e planícies de inundação desses paleoambientes fluviais. Percebe-se que as investigações sugeridas implicam na aproximação da escala de trabalho para a melhor compreensão das relações do relevo, geologia estrutural, sedimentar e áreas afins ao conhecimento geográfico. Isso aplicaria talvez em diferentes análises locais, onde então o conjunto seria mais bem compreendido com uma boa densidade de levantamentos, porém para atingir tais ideias caberá então a novas perspectivas de análises científicas geográficas. / The present research is part of the studies concerning the quaternary evolution of the coastal environments of the coast São Paulo state (Brazil). The coastal plain of Bertioga, with an extension of approximately 45 km, maximum width of only 6 km and depth up to 100 m in the central part (presence of a hemi-graben), it is an example of morphotectonic and eustatic evolution, which results in a complex geological-geomorphological configuration (Souza, 2015). It covers all types of sedimentation environments common on extensive coastal plains as (Quaternary Units - QUs), namely: (a) marine-praial - current beaches (Pr), sandsptis (LHTb) and holocene marine terraces (LHTa), and two generations of low (LPTb) and high (LPTa) marine pleistocene terraces; (b) estuarine-lagoon and paludial - current tide plains (LOL) and colmated holocene estuarine-lagoon depressions, which evolve to current paludal environments (LCD); (c) fluvial - alluvial terraces, sediments of riverbanks and holocene to the latest floodplain (LHF) and Pleistocene (LPF), mixed sediment plains (alluvial and lowland colluvial deposits /debris courses) holocene to the latest (LMP). Several environmental studies that embrace direct or indirectly sedimentological aspects in the coast plain approach the following mean matters: geological, geomorphological and pedological mapping, geochronology, hydrogeology, neotectonics, phytosociology and floristics (vegetation) and ecological risks. The study aims to present the morphotectonic indicators in the continental sediments of Bertioga coastal plain, based on the analysis and compilation of a great data set available. The baseline studies chosen were: average diameter (in mm) and selection degree (in phi) of sediments, deposits and associated soils, and the identification of morphotectonic patterns, as well as an application of techniques in Geoprocessing for an automatic extraction of the drainage network. In overall, the granulometric baselines of the studied QUs are distributed as follows: average diameter - varies between average silt (5.74 fi) to coarse sand (0.33 fi); selection degree - varies from very poorly selected (3.24 fi) to very well selected (0.30 fi). Concerning the associated soils in fluvial and mixed environments they are, Fluvial Neosols, Háplic and Tiomorphic Gleysols, Fluvial and Háplic Cambisols. The quaternary deposits altimetry varies from 0 to 13 m. The main characteristics of each QU are presented as follows: LHF (altitude: 2-5 m) - average diameter between 3.40-3.10 fi; selection degree between 0.38-0.87; NA between 0.5-1.2 m; sub-angled to sub-rounded and smooth grains. LPF (altitude: 7.5-10 m) - average diameter between 4.79-0.32 fi; selection degree between 0,35-3,23 fi; NA between 0.5-1.5 m; rounded to sub-rounded grains. LMP (altitude: 5-7 m) - average diameter between 1.08-4.37 fi; selection degree between 1.99-2.41 fi; NA between 0.2-1.1 m; sub-angled to sub-rounded and smooth grains. The results obtained in the field and in laboratory are defined by the description of the study area, by means of the quaternary geological units, which are considered exclusive for the coast of São Paulo, thus, justifying the objective of this research, the results and considerations presented aimed to integrate the steps studied. Therefore, we can observe that there are many factors that could be interpreted from the analyzes results in geoprocessing, mainly when examining channels and their different forms of analysis. In this phase we tried to reinforce the drainage anomalies presented, they are nothing more than strong tectonics or neotectonics indicators, when we use a sedimentary approach, in the quaternary period, stressed by a landscape view seen by geography, it demonstrates an illustrative dynamic, seeking facilitates the methodologies of environment analysis. The grain size evidence of the energy alternations of transport agents, fluvial waters and rainwaters, promoted the sediment displacement and deposition, corroborating spatial delimitation of these geological units. With the expeditions on the field, it was possible to identify old river channel beds in several plain areas. Sequences of sandy sediment layers in the thick and coarse sand fractions, interspersed with granules and some wood fragments, identified in the sediment collection in laboratory study, evidenced the tracing of old terraces and floodplains of fluvial paleoenvironments. It is noticed that the suggested investigations imply the approximation of the work scale for a better understanding of the relief, structural and sedimentary geology relations and areas related to geographic knowledge. This would, perhaps, apply in different local analyzes, where the set would be better understood with a good density of surveys, but to reach such ideas shall be necessary new perspectives of geographic scientific analysis.
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Evolução geomorfológica e tectônica da porção norte da Bacia do Amazonas : região do Rio Apuaú (AM) /

Nascimento, Mayara Aline Santos Ribeiro do January 2016 (has links)
Orientador: Norberto Morales / Resumo: A paisagem na Amazônia tem mostrado um quadro geomorfológico evolutivo associado a condicionamentos tectônicos no controle da rede de drenagem, com importantes mudanças nos cursos dos rios associadas a sistemas de falhas no âmbito da Neotectônica. Esta pesquisa compreende o estudo da bacia hidrográfica do rio Apuaú, afluente da margem esquerda do rio Negro na sua porção média, a norte de Manaus, no Estado do Amazonas. Foi subsidiada por estudos estruturais e geomorfológicos apoiados em dados de campo, de sensores remotos e de datação dos depósitos aluvionares. Foram reconhecidos blocos desnivelados do relevo, com rupturas de declive (knickpoints) associadas e controladas por falhas. A rede de drenagem apresenta padrões anômalos dos cursos d’água, capturas, meandros e canais encurvados, alinhamento de canais retilíneos, marcando zonas de juntasou zonas de falhas. Os blocos controlam também a distribuição de terraços, paleoterraços e canais abandonados, e suas datações por LOE apontam para depósitos mais antigos na faixa de 53.000 a 62.200 anos, intermediários na faixa de 20.330 a 23.100 anos, e depósitos atuais. O quadro geológico-estrutural aponta para compartimentos morfotectônicos, controlados por falhas normais e falhas transcorrentes destrais associadas. As falhas normais condicionam blocos rotacionados, a rede de drenagem e a distribuição dos depósitos aluvionares, enquanto as falhas transcorrentes parecem balizar e controlar os blocos na porção norte e leste da bacia hi... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
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Evolução geomorfológica e tectônica da porção norte da Bacia do Amazonas: região do Rio Apuaú (AM) / Geomorphological and tectonic evolution of the northern portion of the Amazon Basin: Apuaú River region (AM)

Nascimento, Mayara Aline Santos Ribeiro do [UNESP] 08 November 2016 (has links)
Submitted by MAYARA ALINE SANTOS RIBEIRO null (may.aline@hotmail.com) on 2017-01-05T17:38:34Z No. of bitstreams: 1 Dissertação_Mayara.pdf: 39283902 bytes, checksum: 070cd0b333890899ac8433d3c55582b7 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-10T17:02:25Z (GMT) No. of bitstreams: 1 nascimento_masr_me_rcla.pdf: 39283902 bytes, checksum: 070cd0b333890899ac8433d3c55582b7 (MD5) / Made available in DSpace on 2017-01-10T17:02:25Z (GMT). No. of bitstreams: 1 nascimento_masr_me_rcla.pdf: 39283902 bytes, checksum: 070cd0b333890899ac8433d3c55582b7 (MD5) Previous issue date: 2016-11-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A paisagem na Amazônia tem mostrado um quadro geomorfológico evolutivo associado a condicionamentos tectônicos no controle da rede de drenagem, com importantes mudanças nos cursos dos rios associadas a sistemas de falhas no âmbito da Neotectônica. Esta pesquisa compreende o estudo da bacia hidrográfica do rio Apuaú, afluente da margem esquerda do rio Negro na sua porção média, a norte de Manaus, no Estado do Amazonas. Foi subsidiada por estudos estruturais e geomorfológicos apoiados em dados de campo, de sensores remotos e de datação dos depósitos aluvionares. Foram reconhecidos blocos desnivelados do relevo, com rupturas de declive (knickpoints) associadas e controladas por falhas. A rede de drenagem apresenta padrões anômalos dos cursos d’água, capturas, meandros e canais encurvados, alinhamento de canais retilíneos, marcando zonas de juntasou zonas de falhas. Os blocos controlam também a distribuição de terraços, paleoterraços e canais abandonados, e suas datações por LOE apontam para depósitos mais antigos na faixa de 53.000 a 62.200 anos, intermediários na faixa de 20.330 a 23.100 anos, e depósitos atuais. O quadro geológico-estrutural aponta para compartimentos morfotectônicos, controlados por falhas normais e falhas transcorrentes destrais associadas. As falhas normais condicionam blocos rotacionados, a rede de drenagem e a distribuição dos depósitos aluvionares, enquanto as falhas transcorrentes parecem balizar e controlar os blocos na porção norte e leste da bacia hidrográfica. Reconhecidas em campo, as falhas normais formam dois grandes conjuntos, orientados NE-SW a EW e NW-SE, enquanto as falhas transcorrentes destrais predominam com orientação próxima a EW e transcorrentes sinistrais NE-SW. O tratamento das populações de falhas para obtenção de eixos de paleotensões indica um evento distensivo NNW-SSE a NW-SE, interpretado como mais antigo, um evento distensivo NE-SW a EW, ao qual pode ser atribuído o ajuste dos blocos rotacionados, controlados por falhas NW-SE, e um arranjo compressivo NNW-SSE a NW-SE, responsável pelas falhas transcorrentes, ambos mais jovens. A associação entre as falhas transcorrentes destrais EW balizando os blocos abatidos e rotacionados controlados por falhas normais NW-SE promove o rearranjo da rede de drenagem e o ajuste da distribuição das coberturas superficiais, indicando atuação do regime neotectônico, decorrente da interação da Placa Sulamericana com a Placa do Caribe. / The landscape in the Amazon has shown a geomorphological evolution associated to tectonic constraints in controlling the drainage network, with important changes in the stream courses associated with fault systems within the scope of the neotectonic regime. This research comprises the study of the catchment of the Apuaú river, a tributary of the left bank of the Negro river in its middle portion, North of Manaus, in the state of Amazonas. Structural and geomorphological studies supported by field data, remote sensing and dating of alluvial deposits were carried out. Uneven relief blocks were recognized with associated slope ruptures (knickpoints) and controlled by faults. The drainage network has anomalous patterns of water courses, captures, meanders and curved channels, rectilinear alignment of channels, indicating fracture or fault zones. The blocks also control the distribution of terraces, paleoterraces and abandoned channels, and their LOE datings point to older deposits in the range 53,000 to 62,200 years, intermediate ones in the interval of 20,330 to 23,100 years and current deposits. The geological and structural framework points to morphotectonic compartments controlled by normal faults and associated dextral strike-slip faults. Normal fault constrain rotated blocks, drainage network and the distribution of alluvial deposits, while the strike-slip faults seem to delimit and control the blocks in the northern and eastern parts of the hydrographic basin. Recognized in the field, normal faults adjust into two large sets, oriented NE-SW to EW and NW-SE, while strike-slip faults predominate striking close to EW dextral and NE-SW sinistral ones. Fault population analysis to obtain paleostress axis indicates a NNW-SSE to NW-SE extensional event, interpreted as the oldest, followed by one NE-SW to EW distensive event, which can be attributed to the adjustment of rotated blocks, controlled by NW-SE faults, and a compressive arrangement NNW-SSE to NW-SE, responsible for the slip faults.The association between the EW dextral transcurrent faults controlling uneven and rotated blocks affected by NW-SE normal faults promotes the rearrangement of the drainage system and adjusting the distribution of surface covers, indicating actions of the neotectonic regime, due to the interaction of the South American Plate with the Caribbean Plate.
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Caractérisation de la déformation tectonique récente du système de failles de Belledonne et de l'avant pays alpin (vallée du Rhône) : apports d'une approche pluridisciplinaire / Characterization of the recent tectonic deformation of the Belledonne fault system and of the alpine foreland : contribution of a multidisciplinary approach

Billant, Jérémy 10 March 2016 (has links)
Le but de cette étude est de caractériser par une approche multi-disciplinaire les déformations tectoniques Plio-Quaternaire associées au système de failles de Belledonne (Alpes de l'Ouest).Ce système de faille est composé de plusieurs décrochements qui sont des Bauges au Vercors, la faille dextre NE-SW de l'Arcalod, la faille bordière de Belledonne, dextre et NE-SW, la faille sénestre NW-SE du Brion et la faille NE-SW dextre du Jasneuf.La détermination des états de contraintes tardi-Cénozoique montre que le champ de contrainte actuel responsable de la cinématique en décrochement le long du système de faille de Belledonne date de la fin du Pliocène supérieur/début du Pléistocène et a succédé au champ de contrainte causé par la collision alpine.Les failles de l'Arcalod et du Brion présentent des marqueurs morphologiques décalés mais ambiguës et d'âge incertain (probablement anté-Rissiens). La trace de la faille bordière de Belledonne n'a pu être déterminée, suggérant que la déformation associée à cette dernière soit accommodée dans une large bande de cisaillement.La faille du Jasneuf décale des morphologies d'âges supposés messiniens et anté-Rissiens. La vitesse de cette faille intégrée depuis le messinien serait de 0,13±0,03 mm/an. Considérant que cette faille est limitée à la couverture elle pourrait générer des séismes de magnitude 5,7 tous les ~500 ans.L’accommodation de la déformation actuelle dans l'avant-pays a été étudié dans la vallée de Toulaud (SW de Valence) où une faille tardi-hercynienne recoupe le canyon messinien du Rhône. Les premiers résultats indiquent que la faille décale verticalement le canyon, attestant d'une tectonique Plio-Quaternaire. / The aim of this study is to characterize the Plio-Quaternary tectonic deformations related to the Belledonne fault system (western Alps). The low deformation rates and high erosion rates in the study area imply that a multi-disciplinary approach.From the Bauges to the Vercors massif this fault system is composed of strike-slip faults that are the NE trending right-lateral strike-slip Arcalod fault, the NE trending right-lateral strike-slip Belledonne border fault, the NW trending left-lateral strike-slip Brion fault and the NE trending right-lateral strike-slip Jasneuf fault.The determination of the late Cenozoic stress states revealed that the modern stress field responsible for the Belledonne fault system strike-slip kinematics dates from late upper Pliocene/early Pleistocene and came after the stress field caused by alpine collision.Unclear and undated (but probably pre Rissian) offset morphologic markers are described along the Arcalod and Brion faults. Belledonne border fault trace is not determined suggesting that deformation is accommodated in a wide shearing band.The Jasneuf fault offset morphologies whom ages are supposed Messinian and pre Rissian. Fault slip rate integrated since Messinian would be of 0.13±0.03 mm/yr. Considering that this fault appears limited to the sedimentary cover and excluding an aseismic behavior, she can generate 5.7 Mw earthquake each ~500 years.Modern deformation in the foreland is studied in the Toulaud valley (SW of Valence city) where a late Hercinian fault cross-cut the Messinian canyon of the Rhône river. First results show that the fault offset vertically the canyon, attesting aof Plio-Quaternary tectonics along it.
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Active tectonics of the Doruneh Fault : seismogenic behavior and geodynamic role / Tectonique active de la faille de Doruneh : comportement sismogénique et rôle géodynamique

Farbod, Yassaman 12 June 2012 (has links)
Ce travail de thèse porte sur la tectonique active du système de faille de Doruneh (DFS) situé au NE de l'Iran. Une approche combinée de géologie structurale, morpho-tectonique, géomorphologie quantitative et datation par des nucléides cosmogéniques 36Cl et 10Be nous a permis de décrire la cinématique ainsi que le rôle géodynamique du DFS dans le contexte de la collision Arabie-Eurasie.Le DFS comprend trois zones avec des caractéristiques structurales, géomorphologiques et cinématiques distinctes, (a) inverse-senestre pour la WFZ (Ouest) (b) purement senestre pour la CFZ (Centre) et (c) inverse pour l'EFZ (Est). Les âges d'abandon de trois générations de cônes alluviaux quaternaires ont été déterminés à ~12, ~36 et ~100 ka. Ces âges, combinés avec les décalages mesurés, indiquent une vitesse maximum de déplacement horizontal senestre de ~5,3 mm/an pour l'Holocène. Notre analyse d'aléa sismique indique que la longueur maximale d'un segment sismogène varie de 70 à 100 km, ce qui pourrait produire des séismes caractéristiques de magnitude 7.2 à 7.4 avec des intervalles de récurrence de ~750 ans.Nous proposons un nouveau modèle géodynamique dans lequel l'EFZ est impliquée dans une zone de cisaillement dextre d'orientation NNW entre Iran central et Eurasie. Le mouvement vers le nord de l'Iran central est accommodé dans cette zone de relais en transpression par du raccourcissement sur des failles inverses d'orientation NW, et transféré vers le Nord par des faille dextres d'orientation NNW. / This study focuses on the active tectonics of the Doruneh Fault System (DFS) in the north-eastern part of central Iran. A combined approach of geological and morphotectonic mapping, fault kinematic analysis, as well as in situ-produced cosmogenic dating (36Cl and 10Be) allowed us to characterize the active kinematics and geodynamic role of the DFS in the context of the Arabia-Eurasia collision.The DFS comprises Western, Central and Eastern fault zones (WFZ, CFZ, EFZ) with distinct structural, geomorphic and kinematic characteristics. The WFZ is oblique reverse-left-lateral, the CFZ is pure left-lateral and the EFZ is reverse. Exposure ages of ~12, ~36 and ~100 ka have been determined for three generations of alluvial fan abandonment surfaces along the DFS. Combining geomorphic offsets and their related ages yields a maximum left-lateral slip rate of ~5.3 mm/yr for the CFZ during Holocene. The maximum length of independent seismogenic fault segments varies from ~70 to ~100 km that could produce a characteristic earthquake with a magnitude of Mw =7.2 to 7.4 and recurrence interval of ~750 years.We propose a geodynamic model in which the EFZ is involved in a NNW-trending dextral shear zone between Central Iran and Eurasia. This implies that the EFZ forms a complex right-lateral transpressional relay zone between the eastern and northeastern Arabia-Eurasia convergence boundaries. The northward motion of Central Iran relative to Eurasia is accommodated by shortening on NW-trending reverse faults, and is transferred northward via NNW-trending dextral faults.
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Evolu??o morfotect?nica do maci?o estrutural pereiro, Prov?ncia Borborema

Gurgel, Silvana Praxedes de Paiva 06 August 2012 (has links)
Made available in DSpace on 2015-02-24T19:48:44Z (GMT). No. of bitstreams: 1 SilvanaPPG_TESE_pag119_final.pdf: 4384081 bytes, checksum: f4e3889e03bd2b77ef4e8f1b271723a8 (MD5) Previous issue date: 2012-08-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Northeast relief was described by the Pediplanation Model. This action discards the theoretical basis of post-Cretaceous tectonic evolution of the landscape. Through this model the Massif Pereiro - MP, Borborema Province, was established as part of the Tablelands Area Residual Sertanejos. The present work aims to establish the post- Cretaceous morphotectonic evolution of the MP by geomorphological and geological mapping using Geographic Information System, Remote Sensing and dating of sediments by Single Aliquot Regenerative-dose (SAR). The MP is contained in the core semi-arid, annual precipitation of 600-800 mm / year. The MP is NE-SW, is limited by Shear Zone Jaguaribe (ZCJ) and Portalegre Shear Zone (ZCPa), the same attitude, and crossed by several other shear zones. These shear zones show evidence of brittle Cenozoic reactivation, mostly as normal faults and shallow crustal level. The Quaternary sedimentation around the MP focuses on fault escarpments in a general pattern cascade, where ages decrease from the summits of the steep foothills. The ages of 51 sediment samples indicate a correlation with global climate following pulses: Last Interestadial-UI, the Last Glacial Maximum - LGM and the transition Pleistocene / Holocene, while the latter focus on 18 of 51 samples dated. This study also finds evidence of a new quaternary basin, here called Merejo Basin. Through these results it is concluded that no evidence of post-Cretaceous tectonic evolution of morphological MP, as their retreat along the fault scarps, invariably following the trend of the shear zones. The erosion of cliffs in large time scale is controlled by weakness zones generated by faults on the other hand the erosion of cliffs in short time, with the formation of deposits and colluvial horizons pedogenizados, has climate control. It was also found that in the study area there is a preponderance of past and current tectonic erosion processes on the morphological evolution / O relevo do Nordeste foi descrito por meio do modelo de pediplana??o. Esta base te?rica descarta a atua??o da tect?nica p?s-cret?cea na evolu??o da paisagem. Atrav?s deste modelo o Maci?o do Pereiro MP, Prov?ncia Borborema, foi definido como parte do Dom?nio dos Planaltos Residuais Sertanejos. O presente trabalho tem por objetivo estabelecer a evolu??o morfotect?nica p?s-cret?cea do MP, atrav?s da cartografia geol?gica e geomorfol?gica com uso de Sistema de Informa??o Geogr?fica, Sensoriamento Remoto e data??o de sedimentos por Single Aliquot Regenerative-dose (SAR). O MP est? contido no n?cleo semi?rido, de precipita??o anual entre 600 a 800 mm/ano. O MP tem dire??o NE-SW, ? limitado pela Zona de Cisalhamento de Jaguaribe (ZCJ) e Zona de Cisalhamento Portalegre (ZCPa), de mesma atitude, e atravessado por v?rias outras zonas de cisalhamento. Estas zonas de cisalhamento apresentam evid?ncias de reativa??o fr?gil cenozoica, na sua maioria como falhas normais e de n?vel crustal raso. A sedimenta??o quatern?ria em torno do MP se concentra em escarpas de falhas, em um padr?o geral em cascata, onde as idades diminuem das cimeiras aos sop?s das escarpas. As idades de 51 amostras de sedimentos indicam correla??o com seguintes pulsos clim?ticos globais: ?ltimo Interestadial- UI, o ?ltimo M?ximo Glacial - UMG e a transi??o Pleistoceno/Holoceno, sendo que nesta ?ltima concentram-se 18 das 51 amostras datadas. O presente trabalho tamb?m encontra evid?ncias de uma nova bacia quatern?ria, aqui denominada de Bacia Merejo. Atrav?s destes resultados conclui-se que h? evidencia de tect?nica p?s-cret?cea na evolu??o morfol?gica do MP, pois as suas escarpas recuam paralelamente ?s falhas, seguindo invariavelmente o trend das zonas de cisalhamento. A eros?o das escarpas em grande escala de tempo ? controlada pelas zonas de fraqueza geradas pelos falhamentos, por outro lado ? eros?o das escarpas em curtos espa?os de tempos, com a forma??o dos dep?sitos coluvionares e horizontes pedogenizados, possui controle clim?tico. Concluise ainda que na ?rea de estudo haja a preponder?ncia da tect?nica pret?rita e atual sobre os processos erosivos na evolu??o morfol?gica

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