Έγιναν 12 αβαθείς γεωτρήσεις (μέγιστο βάθος 1,5m) και λήφθηκαν δείγματα ανά 10 εκατοστά, στο νότιο τμήμα της λεκάνης Δαμασίου στη Θεσσαλία. Το σύνολο των δειγμάτων (36 δείγματα) αναλύθηκαν στο εργαστήριο και έγινε επί τόπου περιγραφή των πυρήνων των γεωτρήσεων. Έπιπλέον έγινε λεπτομερής χαρτογράφηση των εδαφών σε κλίμακα 1:5000. Ο στόχος της διατριβής ήταν να υπολογισθεί ο ρόλος των εδαφικών τύπων στην κατείσδυση του νερού στο καρστικό σύστημα Αμυγδαλέας - Τυρνάβου. Τα στοιχεία που προέκυψαν από τις αναλύσεις δείχνουν ότι μόνο κατά θέσεις ενισχύεται το καρστικό σύστημα, αφού η περατότητα΄που υπολογίσθηκε ήταν μικρή. Το μεγαλύτερο μέρος του ύψους της βροχής απορρέει προς τον Τιταρήσιο ποταμό, που βρίσκεται πλησίον της λεκάνης στο βόρειο τμήμα αυτής. / This study is based on a series of 12 shallow boreholes at a maximum depth of about 1,5m, within the southermost part of Damasion basin, Thessaly. From the boreholes we collected 36 soil samples for laboratory analysis while the entire borehole were described in the field using Mansel Index and lithology description. in the laboratoty samples were analysed for grain size analysis, moisture, plasticity, liquid limiti and placticity. In addition the study area were mapped in a scale of 1:5000. In this study, we have taken the opportunity to investigate the role of the soil in the infiltration of water to the karst system Amugdalea - Tyrnabou. The results showed that only in same places water contributed in the underground movement of the karst system. The hydraulic contuctivity had poor to medium values.

Les aquifères karstiques sont caractérisés par un écoulement rapide dans les conduits karstiques et un écoulement lent dans la roche encaissante (matrice). En raison de cet écoulement rapide, ces aquifères sont fortement vulnérables à la pollution. L'objectif principal de cette thèse est d’évaluer l'importance des échanges d'eau à l'interface entre les conduits et la matrice et par conséquent l’impact de ces échanges sur le transport de soluté dans le système karstique. Pour investiguer l’apport de l'équation de Brinkman à l’évaluation des écoulements d'eau, un modèle dont la géométrie du conduit est décrite par la fonction sinus a été établi. Deux scénarii sont appliqués. Le scénario A emploie la loi de Darcy dans le conduit et la matrice. Le scénario B emploie l'équation de Brinkman et la loi de Darcy dans le conduit et la matrice, respectivement. Le terme supplémentaire de l’équation de Brinkman décrivant les forces de cisaillement joue un rôle prédominant sur l'échange d’eau entre le conduit et la matrice lorsque les conduits sont sinueux. Le modèle hydrodynamique - transport a été appliqué au système karstique du Val d’Orléans. La calibration a démontré que le meilleur diamètre moyen du conduit est de 5 m, la perméabilité dans la roche encaissante est de 5,7×10-10 m2 et celle du conduit de 1,65×10-5 m2 à 5,5×10-5 m2. Les prédictions du modèle hydrodynamique - transport ont été comparées aux crues de la Loire observées dans les années 1992 et 1993 durant lesquelles les concentrations en chlorure (traceur naturel conservatif) ont été dosées dans la Loire et à la source du Bouillon. Avec un coefficient d’emmagasinement dans la matrice de 0,9 m-1, la distance pénétrée par l'eau de la crue dans la matrice est d'environ 530 m en deux mois pour une crue de 2 m (exemple de 1993). / The karst aquifers are characterized by a fast flow in the karstic conduits and a slow flow in the matrix. Because of this fast flow, these aquifers are strongly vulnerable to pollution. The main aim of this thesis is to evaluate the importance of water exchanges at the interface between the conduits and the matrix and by consequence the impact of these exchanges on the solute transport in the karst system. To investigate the contribution of the Brinkman equation to the evaluation of the water flows, a model whose geometry of the conduit is described by the sine function was established. Two scenarii are applied. Scenario A employs Darcy’s law in the conduit and the matrix. The scenario B employs the Brinkman equation and Darcy’s law in the conduit and the matrix, respectively. The additional term of the Brinkman equation describing the shear stress plays a predominant role on the water exchange between the conduit and the matrix when the conduits are sinuous. The hydrodynamic - transport model was applied to the karst system of the Val d’Orléans. The calibration showed that the best average diameter of the conduit is of 5 m, the permeability in the hosted rock is of 5.7×10-10 m2 and that of the conduit of 1.65×10-5 m2 to 5.5×10-5 m2. The results of the hydrodynamic - transport model were compared to floods of the Loire observed in the years 1992 and 1993 during which the chloride concentrations (tracer conservative naturalness) were proportioned in the Loire and Bouillon Spring. With a storage coefficient in the matrix 0.9 m-1, the distance penetrated by the water in the matrix is approximately 530 m in two months for a rising of 2 meters (example of 1993).

Made available in DSpace on 2017-07-21T18:15:37Z (GMT). No. of bitstreams: 1 Henrique Pontes.pdf: 12166815 bytes, checksum: 43e10ab43df77d7ee3bcce52071a5be6 (MD5) Previous issue date: 2014-04-23 / This dissertation seeks to understand the spatial distribution of major karst features in Furnas Formation sandstones (Silurian/Devonian) in the Ponta Grossa city (Paraná State). This geological unit, composed of quartz sandstone cemented mainly by kaolinite, is characterized here as a regional karst system composed of several features, such as caves, dolines, sinkholes, depressions in the terrain, kamenitza, alveolus, dissolution conduits, ruiniform reliefs, among others. In this study was investigated only the caves, furnas (collapse dolines) and depressions in the ground, because such elements of karst landscape in question directly influence the management of the territory, because occupation and land use in places of occurrence of these three relief features provide many geo-environmental risks, able to generate economic, environmental and social losses. The carstogenesis of the Furnas Formation karst system undergoes at least three moments of development, with the presence of mechanical removal processes and dissolution, mainly kaolinitic cement, being: 1) rock alteration in underground environment (phantomization, specifically the arenisation in the sandstone), formed from lithologic discontinuities (sedimentary and tectonic structures); 2) process of underground erosion in epiphreatic environment (oscillation zone of the groundwater level) and; 3) arenisation process and mechanical removal caused by the action of rainwater and river water. In total 227 karst features were studied, among them 41 caves (including 14 dolines) and 186 depressions in the terrain. There is a connection between these features because they are aligned, accompanying major structural lineaments, thus showing a peculiar spatial configuration, with intrinsic relationship between each element. With the overlap of the spatial data of caves, dolines and depressions in the terrain with the map of tectonic structures, was possible to see that there is no exclusive relationship with the occurrence of karst features of the Furnas Formation with the Depression of Vila Velha, showing that the karst occurs in sandstones, even in areas where the basement is not carbonate rocks. The map of land use showed that over fifty percent of the landscape in question presents agriculture use and pastoral use, as there is also a large portion of reforestation with exotic. The urban area has a tendency to expand on the karst system and part of the industrial zone is located the rocks of the Furnas Formation. Finally, the present work obtained a map of Environmental Karstic Zoning (EKZ), which presents six specific areas in this landscape, highlighting which are the restrictions of land use in each area. / O presente trabalho busca entender a distribuição espacial das principais feições cársticas das rochas da Formação Furnas (Siluriano/Devoniano), no município de Ponta Grossa (PR). Esta unidade geológica, composta por arenitos quartzosos cimentados principalmente por caulinita, é aqui caracterizada como um sistema cárstico regional, composto por diversas feições, como: cavernas, furnas, sumidouros, depressões no terreno, bacias de dissolução, alvéolos, dutos de dissolução, relevos ruiniformes, entre outras. Neste estudo, optou-se em estudar apenas as cavernas, furnas (dolinas de abatimento) e depressões no terreno, pelo fato que tais elementos da paisagem cárstica em questão influenciam diretamente na gestão do território, pois a ocupação e uso do solo em locais de ocorrência destas três feições do relevo proporcionam riscos geoambientais diversos, capazes de gerar perdas econômicas, ambientais e sociais. A carstogênese do Sistema Cárstico da Formação Furnas passa por pelo menos três momentos de evolução, com presença de processos de remoção mecânica e dissolução, principalmente do cimento caulinítico, sendo: 1) alteração da rocha em ambiente subterrâneo (fantomização, especificamente no arenito a arenização), formada a partir de descontinuidades litológicas (estruturas sedimentares e tectônicas); 2) processo de erosão subterrânea em ambiente epifreático (de oscilação do nível freático) e; 3) processo de remoção mecânica ocasionada pela ação das águas pluviais e fluviais. No total foram trabalhadas 227 feições, dentre elas 41 cavidades subterrâneas (sendo 14 furnas) e 186 depressões no terreno. Observa-se que há uma conexão entre estas feições, pois estão alinhadas, acompanhando grandes lineamentos, mostrando assim uma configuração espacial peculiar, com intrínseca relação entre cada elemento. Com a sobreposição dos dados da espacialização das cavernas, furnas e depressões no terreno com o mapa das estruturas tectônicas, foi possível confirmar a hipótese que atesta não haver relação de exclusividade na ocorrência das feições cársticas da Formação Furnas com a Depressão de Vila Velha, mostrando que o carste ocorre nos arenitos, mesmo em áreas onde o embasamento não é carbonático. O mapa de uso do solo mostrou que mais de cinquenta por cento do relevo em questão apresenta uso com finalidade agropastoril, como também há uma grande porção de reflorestamento com exóticas. A área urbana apresenta tendência de expansão sobre o sistema cárstico e parte da zona industrial está sobre as rochas da Formação Furnas. Por fim, o presente trabalho obteve um mapa de Zoneamento Ambiental Cárstico (ZAC), o qual apresenta seis zonas específicas no relevo em questão, apontando quais são as restrições de uso do solo em cada área.

Variability in the tropical ocean-atmospheric system causes global scale climate anomalies, most evident in the El Niño-Southern Oscillation’s coupled climate feedbacks. Despite being an area of high interest, many questions still remain regarding the west Pacific warm pool’s response to external forcing, particularly its response to increases in anthropogenic greenhouse gases. Paleoclimate reconstructions coupled with model simulations provide insight into the tropical Pacific’s role in past climate variability necessary to the development of robust climate projections. Most paleoclimate records, however, still lack the resolution, length, and chronological control to resolve rapid variability against a background of orbital-scale variations. Here we present stalagmite oxygen isotope (δ18O) reconstructions from Gunung Mulu National Park (4oN, 115oE ), in northern Borneo, that provide reproducible centennial-scale records of western Pacific hydrologic variability that are precisely U/Th-dated and continuous throughout most of the late Pleistocene (0-160 thousand years ago, kybp). The record comprises an entire glacial-interglacial cycle, which allows us to investigate orbital-scale climate forcings and compare two well-dated glacial terminations in the western tropical Pacific. The ice- volume-corrected δ18O records suggest that glacial boundary condtions, which include significantly lower atmospheric carbon dioxide levels, did not drive significant changes in Mulu rainfall δ18O. Similarly, Borneo stalagmite δ18O is poorly correlated to either global sea level shifts or Sunda Shelf areal exposure is not evident. The Borneo record does vary in phase with local mid-fall equatorial insolation, suggesting that precessional forcing may impart a strong influence on hydroclimate variability in the warm pool. This is best illustrated across Glacial Termination II, when the oscillation of equatorial fall insolation is large and out of phase with ice sheet decay. We also use a subset of well-dated, high-resolution stalagmite δ18O records from Mulu to investigate millennial-scale climate variability during Marine Isotope Stages 3-5 (30-100kybp). We find that regional convection likely decreased during the six massive iceberg discharges defined in the North Atlantic sediment records (“Heinrich events”). The inferred drying (increased stalagmite δ18O) during Heinrich events is consistent with a southward shift of the Intertropical Convergence Zone – the dominant paradigm to explain global climate anomalies originating in the north Atlantic (ref). However, any hydrologic variability related to Dansgaad-Oeschgar (D/O) events, millennial-scale sawtooth temperature anomalies of the last glacial period first evident in the Greenland ice records, is notably absent in the stalagmite records. . The Mulu stalagmite record’s absence of D/O signal, however, is in marked contrast to the regional west Pacific marine records and suggests D/O events and Heinrich events may be characterized by fundamentally different climate mechanisms and feedbacks.