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Emprego de dados gravimétricos e de altimetria por satélite como subsídio à análise morfoestrutural na região da Bacia de Pelotas - Rio Grande do SulGagg, Gilberto January 2014 (has links)
Dados de gravimetria e de altimetria por satélite foram usados como subsídio à análise morfoestrutural na região da Bacia de Pelotas-RS. Na abordagem gravimétrica foi usado o modelo geopotencial EGM2008 através das anomalias Bouguer e na abordagem batimétrica foi usado o modelo global DTU10BAT. Através dos mapas de anomalias Bouguer e perfis gravimétricos gerados, verificou-se que as anomalias Bouguer aumentam positivamente da costa em direção às maiores profundidades oceânicas, o que caracteriza um progressivo afinamento crustal associado à deriva continental. O comportamento das anomalias Bouguer obtidas por dados satelitais evidenciaram a presença de uma ruptura conhecida como Charneira Albo-aptiana na plataforma continental. A incidência de valores de anomalias significativamente positivas na região do Baixo de Mostardas sugere a presença de uma massa de maior densidade nesta região. A resolução dos dados gravimétricos utilizados não permitiu evidenciar a presença de paleocanais na região, sendo necessária uma maior resolução espacial, associada a outros métodos de investigação. O uso de dados de altimetria por satélite (modelo DTU10BAT) permitiu a análise batimétrica da plataforma continental e a investigação da configuração morfológica da região, que foi dividida em três faixas: Torres- Farol Solidão, Farol Solidão-Farol da Conceição e Farol da Conceição-Farol Sarita. Foi gerado um modelo teórico e comparado com o modelo DTU10BAT na geração do mapa de anomalias batimétricas. Os eixos de anomalias batimétricas negativas identificados estão frequentemente associados à direção de paleodrenagens, assim como as anomalias positivas tem relação com linhas de paleoestabilizações do nível do mar ou altos estruturais. Foi definida uma sequência de descontinuidades na altura do Farol da Conceição que apresentou expressiva coincidência com paleocanais delineados na mesma região através de outros estudos. Todos os dados foram processados e integrados em um sistema de informações geográficas. Os dados gravimétricos e batimétricos oriundos de missões satelitais são uma grande ferramenta nos estudos regionais para áreas que envolvam aplicações geológicas e mesmo oceanográficas. / Data from satellite altimetry and gravity were used to the morphostructural analysis in the Pelotas Basin-RS region. The EGM2008 geopotential model through the Bouguer anomalies was used in the gravimetric approach and the DTU10BAT global model was used in the bathymetric approach. Through the Bouguer anomalies maps and the gravimetric profiles that were generated, it was observed that Bouguer anomalies increase positively from coast towards to the major ocean depths, what characterizes a progressive crustal thinning associated with the continental drift. The behavior of the Bouguer anomalies obtained from satellite data showed the presence of a rupture, known as Charneira Albo-Aptiana, on the continental shelf. The incidence of significant positive anomalies values on the Baixo de Mostardas region suggests the presence of a higher-density mass in this region. Because of the resolution of the gravimetric data used in this research was not enough, it was not possible to show the presence of paleochannels in the region, requiring a greater spatial resolution data, associated with other methods of investigation. The use of satellite altimetric data (model DTU10BAT) allowed the bathymetric analysis of the continental shelf and the research of morphological configuration of the region, which was divided into three areas: Torres- Solidão Lighthouse, Solidão Lighthouse-Conceição Lighthouse and Conceição Lighthouse-Sarita Lighthouse. A theoretical model was generated and it was compared with the DTU10BAT model in the generation of the bathymetric anomalies map. The axes of negative bathymetric anomalies identified are often associated with the direction of paleochannels, as well as the positive anomalies are related to lines of sea level paleostabilizations or structural highs. It was defined a sequence of discontinuities at the Conceição Lighthouse proximities which presented a significant coincidence with paleochannels that were delineated in the same region through other studies. The data were processed and integrated in a geographic information system. Gravimetric and bathymetric data from satellite missions are an important tool in regional studies for areas that involve geological and oceanographic applications.
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Emprego de dados gravimétricos e de altimetria por satélite como subsídio à análise morfoestrutural na região da Bacia de Pelotas - Rio Grande do SulGagg, Gilberto January 2014 (has links)
Dados de gravimetria e de altimetria por satélite foram usados como subsídio à análise morfoestrutural na região da Bacia de Pelotas-RS. Na abordagem gravimétrica foi usado o modelo geopotencial EGM2008 através das anomalias Bouguer e na abordagem batimétrica foi usado o modelo global DTU10BAT. Através dos mapas de anomalias Bouguer e perfis gravimétricos gerados, verificou-se que as anomalias Bouguer aumentam positivamente da costa em direção às maiores profundidades oceânicas, o que caracteriza um progressivo afinamento crustal associado à deriva continental. O comportamento das anomalias Bouguer obtidas por dados satelitais evidenciaram a presença de uma ruptura conhecida como Charneira Albo-aptiana na plataforma continental. A incidência de valores de anomalias significativamente positivas na região do Baixo de Mostardas sugere a presença de uma massa de maior densidade nesta região. A resolução dos dados gravimétricos utilizados não permitiu evidenciar a presença de paleocanais na região, sendo necessária uma maior resolução espacial, associada a outros métodos de investigação. O uso de dados de altimetria por satélite (modelo DTU10BAT) permitiu a análise batimétrica da plataforma continental e a investigação da configuração morfológica da região, que foi dividida em três faixas: Torres- Farol Solidão, Farol Solidão-Farol da Conceição e Farol da Conceição-Farol Sarita. Foi gerado um modelo teórico e comparado com o modelo DTU10BAT na geração do mapa de anomalias batimétricas. Os eixos de anomalias batimétricas negativas identificados estão frequentemente associados à direção de paleodrenagens, assim como as anomalias positivas tem relação com linhas de paleoestabilizações do nível do mar ou altos estruturais. Foi definida uma sequência de descontinuidades na altura do Farol da Conceição que apresentou expressiva coincidência com paleocanais delineados na mesma região através de outros estudos. Todos os dados foram processados e integrados em um sistema de informações geográficas. Os dados gravimétricos e batimétricos oriundos de missões satelitais são uma grande ferramenta nos estudos regionais para áreas que envolvam aplicações geológicas e mesmo oceanográficas. / Data from satellite altimetry and gravity were used to the morphostructural analysis in the Pelotas Basin-RS region. The EGM2008 geopotential model through the Bouguer anomalies was used in the gravimetric approach and the DTU10BAT global model was used in the bathymetric approach. Through the Bouguer anomalies maps and the gravimetric profiles that were generated, it was observed that Bouguer anomalies increase positively from coast towards to the major ocean depths, what characterizes a progressive crustal thinning associated with the continental drift. The behavior of the Bouguer anomalies obtained from satellite data showed the presence of a rupture, known as Charneira Albo-Aptiana, on the continental shelf. The incidence of significant positive anomalies values on the Baixo de Mostardas region suggests the presence of a higher-density mass in this region. Because of the resolution of the gravimetric data used in this research was not enough, it was not possible to show the presence of paleochannels in the region, requiring a greater spatial resolution data, associated with other methods of investigation. The use of satellite altimetric data (model DTU10BAT) allowed the bathymetric analysis of the continental shelf and the research of morphological configuration of the region, which was divided into three areas: Torres- Solidão Lighthouse, Solidão Lighthouse-Conceição Lighthouse and Conceição Lighthouse-Sarita Lighthouse. A theoretical model was generated and it was compared with the DTU10BAT model in the generation of the bathymetric anomalies map. The axes of negative bathymetric anomalies identified are often associated with the direction of paleochannels, as well as the positive anomalies are related to lines of sea level paleostabilizations or structural highs. It was defined a sequence of discontinuities at the Conceição Lighthouse proximities which presented a significant coincidence with paleochannels that were delineated in the same region through other studies. The data were processed and integrated in a geographic information system. Gravimetric and bathymetric data from satellite missions are an important tool in regional studies for areas that involve geological and oceanographic applications.
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3D structure of the crust and upper mantle beneath Northern Fennoscandian shieldSilvennoinen, H. (Hanna) 02 December 2015 (has links)
Abstract
The crustal and upper mantle structures of the Shield on the regional scale were
investigated using the data of the POLENET/LAPNET passive seismic array and
the previously published models of active and passive seismic experiments in the
study area. This area is centred in northern Finland and it extends to surrounding
areas in Sweden, Norway and northwestern Russia. The bedrock there is mostly of
the Archaean origin and the lithosphere of the region was reworked by two orogenies
during Palaeoproterozoic.
One of the results of the thesis was a new map of the Moho depth of the study area,
for which new estimates of the crustal thickness were obtained using receiver function
method and complemented by published results of receiver function studies and controlled
source seismic profiles. The map differs from the previously published maps in
two locations, where we found significant deepening of the Moho. The 3D structure of
the upper mantle was studied using teleseismic traveltime tomography method. The
resulting model shows high seismic velocities below three cratonic units of the study
area, which may correspond to non-reworked fragments of cratonic lithosphere and a
low velocity anomaly separating these cratonic units from each other.
The regional scale studies were complemented by two smaller scale studies in upper
crust level using combined interpretation of seismic profiling and gravity data. These
studies were centred on Archaean Kuhmo Greenstone Belt in eastern Finland and
central Lapland in northern Finland located in the crust reworked during Palaeoproterozoic.
Both areas are considered as prospective ones for mineral exploration. Both
studies demonstrate the advantage of gravity data inversion in studying 3D density
structure of geologically interesting formations, when the Bouguer anomaly data is
combined with a priori information from petrophysical and seismic datasets.
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Gravimetrická měření a opakovaná nivelace na polygonu Tetčice / Gravity measurements at Tetčice polygonBitalová, Katarína January 2014 (has links)
This master's thesis deals with measurements of highs and gravity of points polygon located in village Tetčice, through which is crossing a eastern fault of Boskovice furrow. With repeated measurement should be proved effect to high levels of groundwater. Repeated measurements are realized in the range 2 stages. In thesis is in detail described calculation complete Bouguer gravity anomaly and their quantitative interpretation. From the gravimetric of dates is created map of complete Bouguer gravity anomaly and interpretative profile through Boskovice furrow. Interpretative profile has localized fault, whose tectonic activity belong to possible factors level movement in the village. Level measurements meets the requirement of precise levelling. The results of the measurements are compared and discussed with the previous stages of the research.
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Měření vertikálního tíhového gradientu na lokalitě TS-73 "Polom", Trutnov - Babí. / Measuring of the Vertical gravity gradient at the locality TS-73 "Polom", Trutnov - BabíPešek, Michal January 2015 (has links)
This master´s thesis deals with the determination of vertical gravity gradient in the shaft below the infantry bunker TS - 73 "Polom" located in village Babí. After performing position, elevation and gravity measurements detailed points, representing the two vertical profiles were calculated gravity, vertical gravity gradient, block densities ang gravity anomalies depending on the depth. Other outputs work as a topographic map and a map of full Bouguer anomalies for the wider area of the location and interpretive geologic profile.
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Gravimetrická měření a opakovaná nivelace na polygonu Tetčice / Gravity measurements and repeated leveling at polygon Tetčice.Zajíčková, Katarína January 2017 (has links)
The object of this master´s thesis was levelling and weight measurement of the Tetčice polygon through which passes the fault of the Boskovice furrow. This is the 10th period of levelling and the second period of gravimetric measurement. The theoretical part describes the geological structure of the site, technology of high-precision levelling and technology of gravimetric measurement. The first part of the practical part deals with my own levelling measurement, the calculation of the resulting cambers and heights, consequential comparasion of the results with previous periods and, especially, with evaluation of the vertical movement tendecies. The second part of the practical part deals with my own gravimetric measurement, the calculation of the complete Bouguer gravity anomaly, creation map of complete Bouguer gravity anomaly and as well as evaluation of gravimetric measurement in relation to the results of the previous periods.
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Downward Continuation of Bouguer Gravity Anomalies and Residual Aeromagnetic Anomalies by Means of Finite DifferencesArenson, John Dean January 1975 (has links)
The depths to buried bodies, characterized by anomalous gravity and magnetic properties, are determined by a combination of two numerical techniques. An upward continuation integral is solved by a method by Paul and Nagy using elemental squares and low order polynomials to describe the behavior of the gravity or magnetic data between observed data points. Downward continuation of the magnetic or gravity data is done by a finite difference technique as described by Bullard and Cooper. The applicability of the techniques are determined by comparison to depths determined by other means over the same anomalies and by comparison to various rule-of-thumb methods prevalent in the geophysical literature. The relative speed and cost of the particular computer system used is also considered in the applicability. The results show that although the initial costs of the computer program are high, the combined technique is as good as and at times better than the rule-of-thumb methods in determining the depth to the anomaly-causing body and is useful when more than just an approximate depth is of interest.
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Nouvelles méthodes de cartographie sur le socle protérozoïque du Sud de Madagascar. Nature et géométrie de la croûte continentale d'un domaine orogénique en convérgence, implications économiques.Randrianasolo, Elisa Brice 05 June 2009 (has links) (PDF)
L'objectif de cette thèse est de contraindre la nature pétrologique et géométrique de la partie profonde d'un domaine orogénique en convergence. Dans ce but, nous avons créé dans un système d'information géographique projeté (Madagascar Laborde 1923), une base de données géologique du tiers Sud de l'île de Madagascar. Les données utilisées sont variées : observations de terrain, images satellites, données topographiques, mesures gravimétriques, radiométriques et aéromagnétiques. L'analyse, le traitement, la confrontation et l'intégration de ces différentes informations (rendues compatibles) nous a permis de réaliser avec précision de nouvelles cartes géologiques de la région, ainsi que des représentations cartographiques nouvelles. Nous mettons notamment en évidence des zones de cisaillements verticales (ZC) majeures et mineures, des fractures, des dykes et des limites lithologiques.<br />Nous précisons la nature des alignements sur l'axe Bongolava – Ranotsara : (i) La structure ductile de direction N 140°, cartographiée dans plusieurs littératures, n'est qu'une impression régionale (à petite échelle) due à la déflexion N 157° des ZC de direction Nord – Sud. La faille de Ranotsara (de direction N 140°) n'existe pas en termes de faille régionale, elle est une impression (à petite échelle) de la restitution cartographique causée par le relais de failles de taille ≤60 km de long et qui sont orientées N 115°, N 140° et N 160°. <br />Nous identifions que les ZC sont les lieux de localisation d'anomalie en éléments incompatibles (U-Th). Elles sont également le lieu de concentration d'oxydes de magnétite et titanomagnétite, associé à la disparition de la biotite. Ces observations soulignent la concentration des magmas et de la fusion au sein des ZC. Ainsi, les ZC sont le lieu de concentration de magmas qui permettent l'advection de chaleur. En effet, dans le Sud de Madagascar les conditions de haute température (800°C) sont homogénéisées sur de grande surface. <br />Nous établissons une nouvelle carte des ensembles lithologiques qui met en évidence des contrastes de compétence: les ZC se développent préférentiellement dans l'ensemble d'orthogneiss peu alumineux; les ensembles de métasédiments alumineux et les gneiss migmatitiques à amphibole sont plus résistants et forment des boudins à différentes échelles ; l'ensemble de granites et syénites stratoïdes et gneiss migmatitiques à amphibole constituent les blocs les plus rigides. Nous identifions des dykes kilométriques de basaltes, de dolérites et de microgranites qui sont orientés préférentiellement sur les directions N 25° et N 120°.<br />Par croisement des données, nous montrons que la position des minéralisations économiques est contrôlée par les anisotropies kilométriques (ZC, charnières de plis, limites lithologiques) qui localisent les circulations fluides et magmatiques. Les minéralisations primaires (métamorphiques ou métasomatiques : corindons, fer et graphite) se localisent au sein des ZC. Les minéralisations secondaires (uranothorianite, or) s'expliquent par des remobilisations au sein des ZC. La position finale des minéralisations s'explique cependant par la géométrie des réseaux hydrographiques et des failles. A l'échelle du Gondwana, la géométrie des ZC majeures néoprotérozoïques contrôle le développement des systèmes de failles et de dykes (170Ma 90Ma) orientés N 160°. <br />Dans 4 régions : Satrokala, Fenoarivo, Analavoka, Lavaraty ; existent des anomalies magnétiques et gravimétriques de type «bulls eyes» qui se localisent à l'intersection des dykes N 160° et des dykes N 30°, N 140° et N 170° ; et parfois avec les ZC. Ces points correspondent à des creux topographiques circulaires (10 m - 2,5 km de diamètre) isolés ou associés en champ de point. Ces zones sont potentiellement des intrusions kimberlitiques. La présence de ces pipes à l'intersection d'anisotropies kilométriques est favorable à l'ascension rapide des magmas silicatés, soit la présence de kimberlites diamantifères.
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