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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.
61

Exumação tectônica e evolução associada do relevo no arco de Ponta Grossa, sul-sudeste do Brasil

Franco-Magalhães, Ana Olivia Barufi [UNESP] 19 November 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-19Bitstream added on 2014-06-13T19:21:56Z : No. of bitstreams: 1 francomagalhaes_aob_dr_rcla.pdf: 5041816 bytes, checksum: 4e36d86919b2c22df4f361432ee24c8f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A evolução do Arco de Ponta Grossa relaciona-se aos diversos eventos de reativação da Plataforma Sul-americana no sudeste brasileiro a partir do Cretáceo Inferior. A análise multi-métodos dos traços de fissão em apatita e zircão no eixo central do Arco de Ponta Grossa permitiu identificar períodos de exumação nas seguintes épocas: (1) Cretáceo Inferior (idades de traços de fissão em zircão entre 138 ± 51 Ma e 107 ± 22), relacionado aos processos tectônicos, magmáticos e de exumação do evento de ruptura do Gondwana Sul-Ocidental; (2) Cretáceo Superior (idades de traços de fissão em zircão entre 90 ± 14 Ma e 69 ± 21 Ma; e idades de traços de fissão em apatitas entre 74 ± 14 Ma e 66 ± 2 Ma), relacionado ao alçamento do embasamento cristalino como resposta à uma anomalia térmica causada pela passagem da Pluma de Trindade sob o sudeste brasileiro, e conseqüente geração tectônica de relevo e erosão que forneceu sedimentos para as bacias de Santos e do Paraná; (3) Cretáceo Superior – Paleoceno Inferior, evento tectônico relacionado a um soerguimento regional que resultou no alçamento e erosão das bordas das bacias da Plataforma Sul-americana, em especial a Bacia do Paraná. Este evento também é associado ao tectonismo gerador das bacias do Rifte Continental Sudeste do Brasil, no segmento central; (4) Oligoceno-Mioceno (idades de traços de fissão em apatitas entre 26 ± 3 Ma e 14 ± 2 Ma) há o registro da mais recente reativação das zonas de falha NW, em especial a Zona de Falha de São Jerônimo-Curiúva, associada ao rearranjo do campo de tensões neste período, e conseqüente erosão das porções de rocha, que marca o início da sedimentação no segmento sul do Rifte Continental Sudeste do Brasil, composto pela Bacia de Curitiba, grábens de Guaraqueçaba, Sete Barras e Cananéia; e as formações Pariqüera- Açu e Alexandra... / The evolution of Ponta Grossa Arch is genetically related to the post-rift reactivation of the South American Platform since Early Cretaceous. Apatite and Zircon lowtemperature thermochronology analysis in Ponta Grossa Arch provided the following interpretations: (1) Zircon fission-track ages between 138 ± 51 Ma and 107 ± 22are related to the tectonic, magmatic and exhumation processes occurred during the Gondwana breakup in Early Cretaceous; (2) Zircon fission-track ages between 90 ± 14 Ma and 69 ± 21 Ma, and apatite fission-track ages between 74 ± 14 Ma and 66 ± 2 Ma are evidenced the basement uplift as a response of thermal anomaly induced by Trindade plume since this time, as also evidenced in other areas of SE-Brazil during Late Cretaceous. The resulting highlands were the main source-area for the Coniacian-Maastrichian sediments of the Santos (Santos formation) and Paraná (Bauru Group) basins; (3) Between Late Cretaceous and Early Paleocene, the tectonic processes caused uplift and erosion of the Paleozoic interior basins, specially the Paraná Basin. At this time, preexisting shear zones were reactivated, formed the Continental Rift Basins of SE Brazil and continental sediments were deposited in these basins at the northern part of the study-area during this time; (4) During Oligocene to Miocene, apatite fission-track ages between 26 ± 3 Ma and 14 ± 2 Ma indicate the youngest reactivation of the NE-SW Precambrian shear zones and consequent exhumation of high elevated area. The origin of the Continental Rift Basins of SE Brazil in the study area (Curitiba basin, Guaraqueçaba, Sete Barras and Cananéia Grabens, and Pariquera-Açu and Alexandra formations) is probably related to the movement along NWSE trending fault zones (São Jerônimo-Curiúva Fault Zone). Thermal histories evidenced local and sea base-level stability and peneplanation processes caused dissection in highelevated areas.
62

Géodynamique et impact de la crise d'érosion et de salinité Messinienne sur les transferts sédimentaires (bassin de Valence, bassin Adriatique) / Perched basins of Mediterranean Sea : geodynamic, and impact of the Messinian salinity crisis on the sedimentary fluxes (Valencia and Adriatic basins)

Pellen, Romain 30 June 2016 (has links)
L’évolution géodynamique et physiographique de l’espace Méditerranéen, en particulier au sein des bassins bordiers de Valence et Adriatique, sont intimement liées à l’héritage anté-Néogène. L’identification de la segmentation des bassins et leur implication dans l’histoire tectonique et environnementale au Néogène, en particulier lors de la crise d’érosion et de salinité Messinienne (MESC - 5.96-5.32 Ma), reste cependant méconnus et font l’objet de ce travail de recherche. Afin de les mettre en lumière, nous proposons une vision complète du remplissage sédimentaire Néogène des deux bassins, sur la base d’une compilation de profils sismiques et de forages industriels. Nos résultats illustrent une segmentation du domaine Valence-Provençal en trois sousbassins d’âges, de subsidences et de nature crustales différentes. Un nouveau scénario cinématique est proposé à l’échelle des bassins Valencien et Algérien. Cette segmentation met en lumière lors de la MESC un système complet de vallées incisées fluviatiles long de plus de 270 km. Associé aux différents cortèges sédimentaires, un nouveau regard est jeté sur l’événement Messinien et le paradoxe d’ouverture du bassin de l’Ebre. Au sein du domaine Adria, l’héritage Mésozoïque contrôle en premier lieu les environnements néogènes, où deux dépocentres majeurs se distinguent de part et autre du seuil composite Apulien-Gargano-Pelagosa. La propagation des fronts de déformations Albanide et Apennin se surimpose à cet héritage et contrôle la sédimentation et les mouvements verticaux de ces dépocentres La période Messinienne est alors perçue comme une phase de réorganisation tectonique majeure, cette dernière se surimposant à la MESC. / The geodynamic evolution of the Mediterranean area, especially in the Valencia and Adriatic basins, is strongly influenced by its ante-Neogene history. The localization of existing thresholds at that time, and their impact on the following tectono- sedimentary evolutions still remain largely unknown. In this work, we will try to reconstruct this evolution and better understand the part of these thresholds, in particular during the Messinian Erosional and Salinity Crisis (MESC, 5.96-5.32 Ma). We provide here a complete view of the Neogene sedimentary infilling for the both Valencia and Adriatic basins thanks to a compilation of seismic profiles correlated to industrial boreholes.Our results allow us to individualize the Valence-Provençal domain into three subbasins whose ages, subsidence and crustal nature differ. A new kinematic and geodynamic scenario for the Valencia and Neogene Algerian basins is proposed here. This segmentation provides also information about MESC. We highlight a fully incised-valley system whose length reaches more than 270 km, the latter associated with the development of several system tracts. Overall, these interpretations lets us look the Ebro basin connection paradox from a different angle.The Mesozoic Apulian-Gargano-Pelagosa composite threshold mainly control the Neogene sedimentation in the Adria domain and distinguishes two main depocenters. The propagating of the Albanid and Apennine deformation fronts control also the evolution of vertical movements and the sedimentation. Our results imply that the Messinian period corresponds to a major tectonic and/or kinematic reorganization phase within which the MSC is a superimposed event.
63

Long-snouted dolphins and beaked whales from the Neogene of the Antwerp area: systematics, phylogeny, palaeoecology and palaeobiogeography =

Lambert, Olivier 15 June 2005 (has links)
This work is mainly based on the collection of Neogene (Miocene-Pliocene) odontocetes (toothed whales) from the area of Antwerp (northern Belgium, southern margin of the North Sea Basin) preserved at the Institut royal des Sciences naturelles de Belgique (IRSNB). <p> The systematic revision of members of the long-snouted dolphin family Eurhinodelphinidae leads to the description/re-description of five species in the genera Eurhinodelphis (E. cocheteuxi and E. longirostris), Schizodelphis (S. morckhoviensis), and Xiphiacetus n. gen. (X. cristatus and X. bossi). Furthermore, the systematic status of several eurhinodelphinid species from other localities in the world is revised. A cladistic analysis with the parsimony criterion is undertaken to highlight the phylogenetic relationships of several eurhinodelphinid taxa with other fossil and extant odontocetes. Eurhinodelphinids are more closely related to the beaked whales; the latter are distinctly separated from the sperm whales. A second analysis, with a likelihood criterion, reaches nearly identical results. Then a separate parsimony analysis investigates the relationships within the family Eurhinodelphinidae; the results suggest sister-group relationships between Schizodelphis + Xiphiacetus and Ziphiodelphis + (Mycteriacetus + Argyrocetus) and a more stemward position for Eurhinodelphis. After that, anatomical, palaeogeographic, and phylogenetic data allow several suggestions about the ecological features of the eurhinodelphinids. The extinction of this family, before the end of the Miocene, is commented, related to the changes in the biodiversity of other odontocete groups and to a contemporary major sea level drop. <p>\ / Doctorat en sciences, Spécialisation biologie animale / info:eu-repo/semantics/nonPublished
64

Paleocurrent Analysis of the Upper Miocene Formation, Los Angeles Basin, California

Bennett, John Newton, Jr. January 1967 (has links)
Almost all sandstone beds occurring in the Upper Miocene formations at the Los Angeles basin were deposited by turbidity currents. Primary textures and structures indicative of turbidites occur in fair abundance throughout all three Upper Miocene formations. All accessible outcrops of the Puente, Modelo, and Upper Miocene portion of the Monterey and Capistrano Formations were scrutinized for sandstone beds containing primary sedimentary structures. Through study of these structures, the direction of current movement was determined. The pattern of current movement displayed reveals that sediment was being transported into the Los Angeles basin from all sides. Current directions and mineralogic studies indicate that essentially three source areas were supplying sediment into the basin. These source areas are 1) the San Gabriel Mountains, 2) an area to the east of the Santa Ana Mountains, and 3) a ridge of metamorphic rock paralleling the present coast line. The majority of sediment was derived from an area in the San Gabriel Mountains located northeast or the basin. This is evidenced by the fact that the thickness, grain size, and total sand content of the Upper Miocene units decrease southwestward across the basin.
65

Evolution stucturale de la marge nord-ouest hellenique dans l'ile de Levkas et ses environs (Grece nord-occidentale)

Cushing, Edward Marc 15 November 1985 (has links) (PDF)
Cette étude régionale traite largement la géologie structurale de l'île de Levkas en Grèce Nord-occidentale. Dans un premier temps il est fait rappel des données stratigraphiques qui concernent les deux domaines isopiques qui constituent file (zone de Paxos et zone ionienne), puis les datations de foraminifères planctoniques viennent compléter les attributions stratigraphiques de son Néogène. La stratigraphie des formations continentales pléistocènes à actuelles est aussi traitée. Une étude détaillée essentiellement basée sur la cartographie permet de préciser la nature et l'âge de la formation des structures plissées ou charriées affectant la série sédimentaire ionienne dans le niveau structural supérieur. On y montre notamment l'importance des phases tectoniques du Miocène moyen (Langhien inférieur) et du Pliocène inférieur, et la présence de plis ou chevauchements déversés vers 1/Est se surimposant aux structures à vergence Est-Ouest classiquement décrites en Grèce de l'Ouest. Une troisième partie montre l'importance des déformations plio-quaternaires dans la région. A Levkas, un important bombement NNE-SSW décakilométrique se forme au cours de la phase compressive du Pléistocène ancien. Celui-ci est assimilable à une voussure anticlinale sur laquelle se forment des failles extensives parfois kilométriques. Cependant des failles décrochantes plurikilométriques dextres normales (10km) fonctionnent du Pléistocène ancien(?) jusqu'à l'Actuel dans la partie occidentale de l'île, laissant supposer l'existence d'un accident décrochant dextre longeant la côte Ouest. Une quatrième partie est consacrée à l'analyse géométrique ou numérique des déformations cassantes ou souples afin de déterminer les modalités de l'application des contraintes au cours de l'histoire tectonique de l'île. Les deux derniers chapitres intègrent les données obtenues à Levkas et régionalement (géologie, géophysique, paléomagnétisme) afin de retracer l'évolution géodynamique de la partie NW de l'arc ionien-lycien puis égéen depuis le Miocène inférieur et jusqu'à l'Actuel. En annexe, de nombreuses données ont été consignées ainsi que l'architecture d'un programme de traitement des données de tectonique cassante fonctionnant sur micro-ordinateur.
66

Morphologie, architecture et dynamique sédimentaire d'une pente carbonatée moderne : le Great Bahama Bank (Bahamas) / Morphology architecture and sedimentary dynamic of a modern carbonate slope : the Great Bahama Bark (Bahamas)

Principaud, Mélanie 14 December 2015 (has links)
Une analyse de données de sondeur multifaisceaux, de sondeur de sédiments (Chirp) et de sismique multitraces, présente la morphologie et la dynamique sédimentaire actuelle ainsi que l’évolution architecturale et stratigraphique du Néogène-Quaternaire opérant le long d’une marge leeward, au nord-ouest du Great Bahama Bank. L’analyse morpho-bathymétrique révèle un talus dominé par de la boue aragonitique, et une grande variété de structures sédimentaires, liées à des processus hydrodynamiques diversifiés. Les courants de density cascading associés aux courants de marée et aux vents d’est représentent les mécanismes de transports édimentaire dominant le long de la marge. La zone de Bimini présente localement un talus court et abrupt,stabilisé en bordure de plate-forme par une barrière récifale, ce qui limite l’export off-bank de sédiments.L’architecture stratigraphique montre une évolution complexe du talus au cours du Néogène. La fin du Paléogène est marquée par un talus continu aggradant détaché de la plate-forme par un escarpement sur faille. Ilpasse à un système très peu incliné de type slope-apron, attaché à la plate-forme au Miocène et se termine par un système en accrétion fortement incliné au Pléistocène. Bien que les dépôts de talus soient dominés par de la boue, ils présentent des variations latérales rapides du Sud au Nord tout au long du Néogène (< 30 km) avec la mise en place de tabliers turbiditiques, de nappes de débrites, et de larges Mass Transport Complexes. Ces faciès interagissent depuis le Langhien avec le Santaren Drift qui s’étend et migre progressivement le long du talus jusqu’à aujourd’hui. Le maximum d’empiétement des contourites se produit au Pliocène supérieur et coïncide avec une réorganisation océanographique globale ainsi que des changements climatiques majeurs dans l’hémisphère nord liés à la fermeture de la Central American Seaway. / An analysis of multi-beam echo sounder, sub-bottom profiler (Chirp) and multichannel seismic,highligths the present-day sedimentary dynamics and the Neogene-Quaternary architectural and stratigraphicevolution along the northwestern leeward margin of the Great Bahama Bank.The morpho-bathymetric analysis reveals an aragonite mud-dominated slope, and a broad spectrum ofsedimentary structures, related to various hydrodynamic processes. The density cascading currents associatedwith tidal currents and prevailing easterly winds correspond to the dominant transport mechanisms operatingalong the margin. The Bimini area displays a short and steep slope, stabilized at shelf edge by rimmed reefalbarrier, which constrains the off-bank export of materials.The stratigraphic architecture shows a complex evolution of the slope during the Neogene. The end ofthe Paleogene is marked by a continuous aggrading slope detached from the shelf by a fault escarpment. It passesinto a low angle slope-apron attached to the platform in the Miocene, and ends with an accretionary system witha steepened slope in the Pleistocene. Although the slope deposits are mud-dominated, they show rapid lateralvariations (< 30 km) from South to North throughout the Neogene with the establishment of turbidite aprons,debrite layers and large Mass Transport Complexes. These facies interact since the Langhian with the SantarenDrift which gradually extends and migrates along the slope until today. The maximum extent of the drift occursduring the upper Pliocene and coincides with a global oceanographic reorganization and major climate changesin the northern hemisphere, related to the closure of the Central American Seaway.
67

Návrh zajištění stavební jámy hloubeného úseku tunelu na vysokorychlostní trati Brno-Přerov / Design of sheeting on a excavated section of tunnel on a high-speed line Brno-Přerov

Umlauf, Jiří January 2020 (has links)
In first part of the thesis are proposed four variants of retaining structures for deep excavation of cut-and-cover tunnel part. It is nailed slope, pile wall, nailed slope in combination with pile wall and soldier pile wall. For those structures is in following part carried out an economic analysis and the most cost effective variant is chosen. Chosen structure is further analyzed in next part. This analysis is carried out with finite element method in software PLAXIS. As a material model is chosen Hardening Soil model and input parameters were determined by empiric formulas from literature. Behavior of neogene clays, in which is the structure designed, is considered as undrained, by type Undrained A. In the last part of the thesis is described technological procedure of construction this retaining structure.
68

Palaeoekologie interakcí rostlin a členovců ze spodního miocénu mostecké pánve v severních Čechách / Palaeocology of plant-arthropod associations from the Lower Miocene of the Most Basin in northern Bohemia (Czech Republic)

Knor, Stanislav January 2010 (has links)
Terrestrial plants and insects account for the majority of the Earth's biodiversity today, and almost half of all insect species are herbivores. Thus, insects and plants share ancient associations date back for more than 400 million years. However, investigation of their interactions stands largely at the beginning in Western Europe. Nearly 4300 plant remains showing various kinds of feeding damages are available for the present study. These trace fossils are classified as so-called functional feeding-groups supply an outstanding example of the complexity, the structure and the changes of terrestrial ecosystems, are not well known during this interval. In Europe, the Neogene is characterized by palaeogeographic re- organization due to the collision of the African with the Eurasian plates. The Neogene plant record in Europe is rich and diverse offering a profound large-scale understanding of the floristic and vegetational development. A database of fossil traces from the Most Basin was compiled and analyzed by various statistical methods in terms of the diversity and intensity of palaeo-herbivory. The primary objective is to present results on the development of insect herbivory through the section of the Bílina Mine in North Bohemia, with the aim of understanding principal factors that caused the...
69

Stratigraphy and Depositional History of the Pantano Formation (Oligocene-Early Miocene), Pima County, Arizona

Balcer, Richard Allen January 1984 (has links)
The Pantano Formation comprises 1,250 m of alluvial, fluvial, lacustrine, and volcanic rocks deposited in a basin formed in response to regional extension during mid- Tertiary time in southeastern Arizona. During deposition, the locations and composition of sediment source areas varied as contemporaneous uplift occurred adjacent to the basin. The lower half of the formation was deposited as alluvial fans that prograded northward, westward, and southward; the upper half was deposited during southwestward retreat of alluvial fan deposition and the onset of lacustrine deposition. An andesite flow separates the two depositional regimes. Radiometric dates of 24.4 ± 2.6 m.y. B.P. for the andesite and 36.7 ± 1.1 m.y. B.P. for a rhyolitic tuff disconformably underlying the formation indicate that deposition occurred during Oligocene to early Miocene time. Proper stratigraphic sequencing and description, paleocurrent analysis, and gravel provenance study aided in understanding the depositional history of the formation.
70

Precambrian Geology of the Cottonwood Cliffs Area, Mohave County, Arizona

Beard, Linda Sue January 1985 (has links)
A belt of Early Proterozoic rocks crops out in the Cottonwood Cliffs area, northwest Arizona. The belt contains an eastern and a western assemblage separated by the Slate Mountain fault. The western assemblage consists of mafic to felsic metavolcanic rocks, metapelites, and metaconglomerates. The eastern assemblage consists of phyllites, felsic to intermediate metavolcanic rocks, metagraywackes, and metagabbro bodies. The belt is bounded to the east by foliated granodiorite. The Valentine granite intruded the belt on the west and north. Steeply-plunging lineations and fold axes, and northeast-trending vertical foliation dominate the structural fabric. The regional elongation direction is near-vertical, as indicated by mineral and pebble lineations, and is parallel to fold axes. Although only one deformational event is evident, the intensity of that event may have obliterated evidence of any earlier deformation. Tertiary basalts and the Peach Springs Tuff locally overly the metamorphic rocks. Cenozoic normal faults in the area are mostly of minor displacement.

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