Master of Science / Department of Geology / Allen W. Archer / Abstract This study compares the tidally influenced facies found within the Tonganoxie Sandstone Member (Stranger Formation, Douglas Group) (Upper Pennsylvanian) of northeastern Kansas with similar facies directly observed in the upper intertidal mudflats of Turnagain Arm of Cook Inlet (Alaska, USA). The two settings contain strikingly similar facies that are characteristic of upper macrotidal estuaries with a strong influence of tidal activities. Identical aspects and features found within both settings include rhythmic vertical variation in stratum thicknesses (cyclic tidal rhythmites), high estimated sedimentation and aggradation rates, and biogenic and physical sedimentary structures (e.g., drag marks, raindrop impressions, arthropod traces and tetrapod trackways, zigzag burrows, runoff washouts, and upright trees, among others). Tidal rhythmites are the most important evidence that is indicative of the tidal influence on the depositional processes of these two study areas. Such cyclic tidal rhythmites have been reported and described from several Carboniferous settings in the eastern USA. Modern analogs to these Carboniferous rhythmites are usually found within upper macrotidal estuarine depositional environments, especially within fluvio-estuarine transitional zones. These environments are distributed over a wide range of modern latitudes. Using cyclic tidal rhythmites as modern analogs for interpreting similar ancient facies is a powerful tool for paleogeographic and paleoenvironmental reconstructions, although it is somewhat a new approach.

In this study a multiproxy approach (including sedimentary techniques, diatoms, molluscs, foraminifera, sedimentary pigments, isotopes, pollen and plant macrofossils) has been adopted to assess environmental change over the last ~9,000 years at three Danish coastal sites (Kilen, Norsminde Fjord and Korup Sø). Particular focus has been placed on periods of intense human coastal occupation, identifiable in Denmark's rich coastal archaeological record (i.e. shell midden accumulation periods), to test critically, hypotheses that changes in the marine environment were contemporary with major cultural and societal changes over the last ~9,000 years. For example, it has been proposed that a decrease in salinity was responsible for the widespread oyster decline, apparent in the Neolithic layers of a number of Danish shell middens. This hypothesis, however, remains speculative to date, lacking any high-resolution and quantitative salinity data covering the Mesolithic-Neolithic transition. Inside the agricultural era, two more phases of shell midden accumulation occur (i.e. during the Pitted Ware/Single Grave cultural period and the Iron Age), suggesting that people must have returned to the sea at these times for increased exploitation of its resources. A diatom-based salinity transfer function (WAPLS-C3 model, r2 boot = 0.923, RMSEP= 0.36 square root salinity units) based on a trans-Baltic training set has been applied to fossil diatom datasets from each site for quantitative assessment of salinity change over the study period. The multiproxy results presented in this study demonstrate a close connection between environmental change and human exploitation of marine resources over the Holocene. This relationship, however, is complex, with the individual fjord systems often exhibiting spatially different responses (i.e. variations in the sedimentary regime, salinity, productivity and nutrient status) to changes in key forcing mechanisms such as sea level change, climate change and human impact upon the catchment (following the introduction of agriculture). Environmental hypotheses for cultural change are reviewed on the basis of the evidence presented in this study. Diatomenvironmental relationships have also been modelled (using multivariate techniques) at Korup Sø and Norsminde Fjord using proxy data as ‘predictor' variables for changes in the terrestrial and marine environment. These results suggest that a variety of marine, climatic, human and catchment related processes are important in explaining a proportion of the variation in the fossil diatom datasets, but these influences tend to vary temporally throughout the profile (e.g. human impact becomes important after ~3,900 BC).

This thesis uses palaeolimnological records to reconstruct Holocene ontogeny trends from four lakes in south western Greenland. The research addresses four hypotheses investigating how Holocene lake ontogeny trends vary under different climatic settings, how long-term changes in ontogeny relate to periods of established climatic change in the region, the similarities between proxies within the lakes and between the lakes, and the role of vegetation in lake ontogeny. The study region occupies the widest ice-free area of south western Greenland and is characterised by a climatic gradient. The area inland and nearer to the ice-margin is arid, receives less precipitation and is warmer relative to the coastal areas. A paired lake approach, using lake records from two inland lakes and two coastal lakes, was adopted to examine the role of climatic setting upon lake development trajectories. Specifically, diatoms were used to reconstruct DI-alkalinity from the lakes using a DI-alkalinity model created from existing training sets in the region (WA Cla model, r2boot = 0.76, RMSEP = 0.28 log alkalinity units), sedimentary pigments to investigate trends in production and sedimentary parameters to reconstruct organic and minerogenic accumulation rates. All four lakes experienced comparable Holocene long-term ontogeny trajectories; maximum alkalinity in the first ~ 1000 cal. year BP of deglaciation followed by maximum production during the peak of Holocene Thermal Maximum (HTM) warming (~7000 -6000 cal. years BP). Following the HTM, all lakes demonstrated oligotrophication and a decline in pH. Vegetation development and catchment stabilisation at the end of the HTM may be important in determining the onset of oligotrophication in vegetated catchments. However, the impact of vegetation development on lake ontogeny cannot be isolated from the changes in the lakes associated with the colder and wetter climate which occurred at the end of the peak HTM warming. The timings of the large transitions in the ontogeny trajectories are comparable with established periods of Holocene climatic variability in the region; climate forcing drives ontogeny in these lakes. However, there are short-term differences between the lakes indicating that lakes have different thresholds of ecological change and may respond differently to the same climate forcing. It is concluded that ontogeny is driven by climate but lakes may respond differently to forcing depending on catchment specific characteristics which can filter out the climate signal or cause climate to influence the lake in a more direct way.

Les études sédimentologiques et biostratigraphiques menées au Liban couplés avec données sismiques 2D de réflexion en mer ont permis de proposer un nouveau cadre tectono-stratigraphique pour la région Levantine a partir du Mésozoïque. L'interprétation sismique soutenue par une analyse détaillée des faciès à permis de représenter les environnements de dépôt au large du Liban où aucun puits n'a été foré. Le rifting dans le bassin du Levant prend fin au Jurassique moyen. L'initiation de subduction de la plaque Afro-Arabe sous l'Eurasie au Crétacé supérieur est suivie par des mouvements décrochants à partir du Miocène. L'interaction entre ces événements géodynamiques ainsi que les fluctuations du niveau marin affecte le remplissage sédimentaire du bassin. Au cours du Jurassique et du Crétacé, la marge Levantine est dominée par l'évolution de plate-forme carbonatée tandis qu'un système mixte (silicoclastic et carbonaté) en eau profonde ont prévalu dans le bassin au cours de l'Oligo-Miocène. Trois grandes voies sédimentaires sont attendus à conduire d'importantes quantités de matériel clastiques dans le bassin: (1) les canyons incisant la marge, (2) la région de Lattaquié (Syrie) et (3) le fan profond du Nil. L'analyse régionale des systèmes de drainage a été réalisée pour estimer la contribution au remplissage du bassin des différentes sources de sédiments. Un modèle stratigraphique, Dionisos, a été utilisé pour tester les scénarios du remplissage du bassin pendant le Miocène Moyen et Supérieur. Une comparaison avec les systèmes de drainage actuels a permis une meilleure évaluation de la plausibilité des volumes sédimentaires attendus pour chaque source. / Sedimentological and biostratigraphic investigations onshore Lebanon coupled with 2D offshore reflection seismic data allowed proposing a new Mesozoic-Present tectono-stratigraphic framework for the northern Levant Margin and Basin. The seismic interpretation supported by in-depth facies analysis permitted to depict the potential depositional environments offshore Lebanon as no well has yet been drilled. The Levant region has been affected by successive geodynamic events that modified the architecture of its margin and basin from a Late Triassic to Middle Jurassic rift into a Late Cretaceous subduction followed by collision and Miocene-Present strike slip motion. The interplay between major geodynamic events as well as sea level fluctuations impacted on the sedimentary infill of the basin. During Jurassic and Cretaceous, the Levant Margin is dominated by the aggradation of a carbonate platform while deepwater mixed-systems prevailed in the basin during the Oligo-Miocene, three major sedimentary pathways are expected to drive important quantities of clastic material into the Levant Basin: (1) canyons along the Levant Margin, (2) the Latakia region (coastlal Syria) and (3) the Nile Deep sea cone. Regional drainage system analysis was performed to estimate the contribution of the different sediment sources to the infill of the basin. A numerical stratigraphic forward model, Dionisos, was used to test the Middle-Late Miocene source-to-sink scenarios permitting to better assess the plausibility of the expected sedimentary volumes for each source through a comparison with actual drainage systems

Le littoral méditerranéen oriental du Maroc compris entre l’oued Kiss et le Cap des Trois Fourches s’étire sur près de 120 km. Ce littoral, objet de notre étude, est caractérisé par des unités morphologiques variées : embouchure, baies, lagune, plages, flèches sableuses, tombolo, falaises (vives et mortes). C’est une zone particulièrement intéressante pour l’étude et la compréhension de l’influence des processus naturels et anthropiques sur la dynamique sédimentaire. L’augmentation des activités industrielles et l’urbanisation croissante ont conduit ces dernières années à la construction de nombreux ouvrages le long de la côte, conduisant à des modifications dans la distribution des sédiments et à une dégradation de l’environnement naturel de certaines plages. L’étude sédimentologique couplée à l’analyse des photos aériennes de plusieurs missions a permis de caractériser les différents environnements de ce littoral, de reconstituer la dynamique des différents environnements sédimentaires et de souligner les facteurs, les processus hydrologiques et hydrographiques qui contrôlent ce littoral méditerranéen. Les analyses minéralogiques, en particulier l’étude des minéraux lourds, nous ont fourni des indications sur l’origine des sédiments, la nature du bassin versant fournisseur, également ont permis de mettre évidence deux secteurs morphosédimentaires de part et d’autre de l’embouchure de la Moulouya. Á l’Est, on trouve un secteur en démaigrissement et un secteur en accrétion est situé dans la partie Ouest de l’embouchure de la Moulouya. L'évolution morphodynamique de chacun de ces deux secteurs résulte des interactions entre les facteurs naturels et l’impact des aménagements réalisés sur cette portion de littoral / The Eastern Mediterranean coastline of Morocco ranging between Kiss and the Cap of the Three Fourches is stretched along nearly 120 km. This littoral, the object of our study, is characterized by varied morphological units: mouth, bays, lagoon, beaches, sand, tombolo, cliffs (formed and dead). It is a particularly interesting zone for the study and the comprehension of the influence of the natural and anthropic processes and sedimentary dynamics. During the last few years the increase in the industrial activities and the increasing urbanization led to the construction of many works along the coast, leading to modifications in the distribution of the sediments and to a degradation of the natural environment of certain beaches. The sedimentological study coupled with the analysis of aerial photographs (of several missions) made it possible to characterize the various environments of this littoral, to reconstitute the dynamics of the various sedimentary environments and to underline the factors, the hydrological and hydrographic processes which control this Mediterranean coastline. The mineralogical analysis, the study of heavy minerals in particular, provided indications on the origin of the sediments, the nature of the catchment supplier area and made it possible to put two morphosedimentary sectors obvious on both sides of the mouth of Moulouya. The morphodynamic evolution of each one of these two sectors results from the interactions between the natural factors and the impact from the installations carried out on this portion from littoral

A Ressonância Magnética Nuclear (RMN) é uma das técnicas mais versáteis de investigação científica experimental, com destaque para o estudo da dinâmica, estrutura e conformação de materiais. Em particular, sua utilização na ciência do petróleo é uma de suas primeiras aplicações rotineiras. Metodologias desenvolvidas especificamente para atender esta comunidade científica mostraram-se desde cedo muito úteis, sendo o estudo da interação rocha/fluido uma de suas vertentes mais bem sucedidas. Desde então, importantes propriedades petrofísicas de reservatórios de óleo e gás têm sido determinadas e entendidas, tanto em laboratório quanto in-situ, nas próprias formações geológicas que armazenam esses fluidos. Entre estas propriedades, a permeabilidade, porosidade e molhabilidade de um reservatório figuram dentre as mais importantes informações estimadas. Com essa finalidade, a determinação e correlação dos possíveis efeitos que a interação rocha/fluido pode causar nos fenômenos de relaxação magnética e difusão molecular, tais como influência da susceptibilidade magnética e geometria do espaço poroso, foram estudados em onze rochas sedimentares retiradas de afloramentos, que possuem propriedades petrofísicas similares àquelas apresentadas por rochas reservatório de petróleo. Os resultados mostraram que os tipos de interação rocha/fluido, detectáveis pelos experimentos de RMN, são por sua vez influenciados pelas características geométricas e estruturais do meio poroso, sendo possível obter essas informações pelos resultados de RMN. Assim, este trabalho teve como objetivo principal estudar e estabelecer essas correlações, afim de se obter informações petrofísicas com maior acurácia e abrangência. Em particular, o estudo da razão T1/T2, que é a razão entre os tempos de relaxação longitudinal e transversal, típicos parâmetros envolvidos numa medida de RMN, mostrou ser um parâmetro útil no estabelecimento destas correlações. Ainda, diferentes metodologias para se medir estes e outros parâmetros de RMN foram estudadas e propostas, cuja interpretação conjunta mostrou ser fundamental para o entendimento dessas correlações. A permeabilidade das rochas, importante parâmetro que define as propriedades de transporte de fluidos dentro da matriz porosa, foi estimada aplicando-se essas metodologias propostas, mostrando excelentes resultados. Através do uso da técnica de RMN em estado-estacionário, esses resultados podem ser estendidos para a escala de well-logging, fato que aumenta consideravelmente a importância desses resultados. Uma vez consolidadas as medidas in-situ, as metodologias propostas deverão auxiliar a indústria de exploração e produção de petróleo a otimizar seus métodos e estratégias de produção, reduzindo seus custos e aumentando a vida útil de seus reservatórios. / The Nuclear Magnetic Resonance (NMR) technique is one of the most versatile techniques for scientific research, specially for the study of dynamics, structure and conformational of materials. In particular, its application in oil science is one of its first routine applications. Methodologies developed specifically to match this scientific community proved to be very useful, and the study of rock/fluid interactions is one of its most successful cases. Since then, important petrophysical properties of oil and gas reservoirs have been determined and understood both in the laboratory and inside the geological formations that store those fluids. Among these properties, the permeability, porosity and wettability of a reservoir formation are the most important information to be estimated. For this purpose, the determination and correlation of possible rock/fluid interaction effects that cause alterations on magnetic relaxation phenomena and molecular diffusion, such as the influence of the magnetic susceptibility and geometry of the porous space, were studied in eleven sedimentary rock cores taken from outcrops, since they have the same petrophysical properties presented by oil reservoir rocks. The results obtained confirmed that the types of rock/fluid interactions, detectable by the NMR experiments, are for instance influenced by the porous media geometry and structure, being possible so to obtain such information using those NMR results. Thus, the main goal of this work was the study and establishment of these correlations, in order to obtain petrophysical information with greater accuracy and comprehensiveness. In particular, the study of the T1/T2 ratio, which is the ratio of longitudinal and transverse relaxation times, common parameters strongly involved in a typical NMR measurement, was found to be useful in establishing those correlations. Moreover, different methodologies to measure this and other NMR parameters were studied and proposed, whose joint interpretation proved to be fundamental for the success of these correlations. The permeability of the rocks, an important parameter that controls the fluid transport properties inside the porous matrix, was estimated using the proposed methodologies, showing excellent results. Appling the steady-state NMR technique, those results could be extended to the well-logging scale, which could improve considerably the importance of that results. Once confirmed in measurements in-situ, the proposed methodologies will be able to help the production and exploration industry to optimize their production methods and strategies, thereby reducing production costs and increasing the reservoir lifetimes.

O estudo de três testemunhos rasos (até 2,5m de profundidade) coletados na região de Jaguaruna, litoral centro-sul de Santa Catarina, permitiu reconstituir parte da história de evolução sedimentar holocênica na área. Para isso, foi feita a análise integrada de quatro tipos de variáveis: sedimentológicas, diatomológicas, palinológicas e geoquímicas (Ctotal, Ntotal, 13C e 15N). Os dados de micropaleontologia foram tratados por métodos de estatística mutivariada (análise fatorial de correspondência, análise de componentes principais e classificação ascendente hierárquica), que evidenciaram agrupamentos significativos entre os microfósseis e, desse modo, auxiliaram nas interpretações. A ca. 5000 anos AP, a área de estudo deveria ser ocupada por um conjunto de lagunas interconectadas, cuja existência pôde ser atestada pelos sedimentos de fundo lagunar, na base de um dos testemunhos, em zona atualmente colonizada por mata de restinga. A ligação da laguna com o mar, nesta época, é verificada pela presença de diatomáceas marinhas e pelo sinal isotópico e elementar da matéria orgânica preservada nos sedimentos, indicativo de origem algácea, com valores de 13C de fitoplâncton marinho. A perda da conexão da laguna com o oceano ocorreu em diferentes momentos nos três testemunhos, sendo o último registro de desconexão da laguna observado a ca. 2740-2370 anos cal AP. Variações nas assembléis de diatomáceas no registro da fase lagunar (de 5500 até 2740-2370 anos cal AP) indicaram pelo menos dois períodos de mudanças maiores na salinidade da paleolaguna. Estes períodos puderam ser comparados a dados de paleoprecipitação, publicados em trabalhos anteriores, obtidos para o Estado de Santa Catarina. Observou-se boa correlação entre períodos com maior precipitação e períodos de diminuição na salinidade das águas da laguna, o que seria relacionado à sua diluição por maior aporte fluvial, sem excluir, no entanto, a possibilidade de menor influência marinha devido a dinâmica de abertura e fechamento das conexões da laguna com o oceano. O registro da vegetação através da analise palinológica auxiliou na elaboração do modelo evolutivo da área e permitiu reconstituir parte da história da vegetação no contexto de preenchimento da bacia lagunar. O desenvolvimento da vegetação de restinga em áreas antes ocupadas por vegetação característica de borda lagunar reforçaria a idéia de progradação das fácies costeiras assoreando por completo a paleolaguna na área. A síntese dos dados palinológicos entre os três testemunhos permite interpretar que, pelo menos desde 4000 anos cal AP, a vegetação na área de estudo não sofreu grandes modificações, o que sugere clima semelhante ao presente. A análise integrada dos diferentes indicadores paloambientais sugere que a dinâmica sedimentar deve ser a maior responsável pelas mudanças observadas nos três testemunhos, com evolução dos ecossistemas ligada, principalmente, a variações no regime e substrato deposicionais, relacionadas à progradação costeira. / Sediments from three cores collected in Jaguaruna (south Brazilian coast, Santa Catarina state) were analyzed, in order to reconstruct the Holocene sedimentary evolution of the area. The palaeoenvironmental reconstruction was based on microfossil proxies (diatoms, pollen and spores), analysis of sedimentary organic matter (13C, 15N and C/N ratios), and sedimentological analysis. From at least 5000 cal yr AP, the site was occupied by a system of interconnected lagoons, whose existence is verified in the core sediments by the record of paleolagoon sediments in area occupied by restinga forest nowadays. The existence of this lagoon and of its connection with the sea is indicated by the presence of marine diatoms and by the isotopic and elementary composition of the sedimentary organic matter, which is indicative of algal origin, with 13C values of marine phytoplankton. The end of the connection between sea and lagoon was registered in different moments in the three cores and the last record of disconnection is found in ca. 2740-2370 cal yr AP. The variations of the diatom assemblages from the lagoonal phase (between 5000 and 2740-2370 cal yr AP) indicated at least two periods of major changes in the paleolagoon salinity. These periods could be compared with the published paleoprecipitation data for the Santa Catarina state, which showed a good correlation between higher precipitation and reduction in the lagoon water salinity. This correlation would be related to dilution of water salinity by the greater fluvial discharges. However, it can not be exclude the possibility of a lower sea influence related with the dynamics of opening and closing connections between lagoon and ocean. The pollen analysis allowed the reconstruction of part of the vegetation history in the context of lagoon basin sedimentary filling. The development of the restinga forest in areas previously colonized by open vegetation around the lagoon suggested the progradation of coastal facies that completely filled paleolagoon in the area. The synthesis of the palinological data showed that no major changes of the mainland vegetation ecosystem took place at least since 4000 cal yr AP. The vegetation in the study area did not suffer great modifications; with no record of climatic changes. The multi-proxies analysis suggests that the sedimentary dynamics must be responsible for the greater changes observed in the core sediments. The evolution of ecosystems could be related to variations of the depositional process and modification in the character of the substratum, related to the coastal progradation.

O estudo do intemperismo é de suma importância uma vez que a quebra química de minerais instáveis termodinamicamente na superfície da Terra por agentes do intemperismo é uma parte fundamental na ciclagem de elementos global. Esse processo é responsável pela formação dos solos dos quais depende toda a vida terrestre, desempenhando um papel central no controle da fertilidade dos solos através do fornecimento de muitos nutrientes que permitem o crescimento das plantas. Atualmente as análises relacionadas ao intemperismo são realizadas através de índices matemáticos ligados à presença ou ausência de determinados minerais e observação do comportamento dos elementos químicos ao longo do perfil de solo. Surge, portanto, a necessidade de técnicas mais rápidas e eficazes. Os objetivos do presente trabalho foram o de caracterizar e avaliar o potencial de vários instrumentos sensores próximos na identificação dos processos de intemperismo em cortes verticais originados de diferentes materiais de origem numa região de São Paulo, Brasil. Cinco perfis de solo com materiais de origem contrastantes (sedimentar e magmático) foram utilizados para a avaliação da espectroscopia como ferramenta capaz de identificar as mudanças ocorridas no perfil durante o intemperismo. Amostras de terra foram coletadas e enviadas para análises química, física, mineralógica e espectroscópica. As análises por sensoriamento próximo em laboratório foram realizadas utilizando três sensores, cada um contemplando uma região do espectro eletromagnético (raio x, visível e infravermelho). No campo, utilizou-se o sensor de raios gama e a câmera multiespectral AISA fênix que realizou a leitura, nas regiões espectrais do visível ao infravermelho de ondas curtas, de todo o perfil de solo desenvolvido sob arenito. Fez-se a descrição elementar, mineralógica e de outros atributos presentes nas amostras de terra coletadas a fim de avaliar a intensidade de intemperismo de cada horizonte dos perfis de solo. Esses dados foram utilizados na descrição do comportamento dos espectros. Os índices de intemperismo e os óxidos maiores foram quantificados a partir de modelos lineares e multivariados utilizando os dados do sensor gama e do visível ao infravermelho (Vis-IR), respectivamente. Os óxidos foram espacializados nas imagens do sensor AISA Fenix para a observação visual do comportamento dos elementos e minerais ao longo dos perfis. Calculou-se a diferença elementar entre horizontes a partir dos dados de fluorescência para comparação com o balanço de massa calculado pelos dados fornecidos pelas análises tradicionais e utilizou-se toda a região espectral, em separado e em conjunto, para a segregação das amostras de acordo com a intensidade de intemperismo. A partir do comportamento das curvas espectrais na região do visível ao infravermelho médio, foi possível identificar a diferença na textura dos horizontes, a presença de água estrutural e no solo, a influência da matéria orgânica e os principais minerais que são reflexos da intensidade de intemperismo de cada horizonte dos perfis analisados. Os dados dos sensores GAMA e FRX apresentaram altos valores de correlação com os óxidos e índices utilizados na quantificação da intensidade de intemperismo, indicando à viabilidade dos sensores para o cálculo dos índices. Os modelos de quantificação dos índices de intemperismo e dos óxidos apresentaram R² acima de 0,5. A aplicação do modelo do Vis-IR às imagens da AISA permitiu quantificar os óxidos pixel a pixel ao longo do perfil e observar a diferenciação dos horizontes, facilitando a interpretação da análise de intemperismo. Devido à especificidade de cada região espectral para analisar um objeto, a utilização de vários sensores que trabalham em diferentes comprimentos de onda pode ser uma alternativa para a mais rápida avaliação da intensidade de intemperismo ocorrendo em perfis provenientes de diferentes materiais de origem. / The study of weathering is of paramount importance since the chemical breakdown of thermodynamically unstable minerals on the surface of the earth by weathering agents is a fundamental part of the cycling of global elements. This process is responsible for the formation of soils on which all terrestrial life depends, playing a central role in soil fertility control by providing many nutrients that enable plant growth. Currently the analyzes related to weathering are performed through mathematical indexes linked to the presence or absence of certain minerals and observation of the behavior of the chemical elements along the soil profile. There is therefore a need for faster and more effective techniques. The objectives of the present work were to characterize and evaluate the potential of several proximal sensing instruments in the identification of weathering processes in vertical cuts originating from different rock parents in a region of São Paulo, Brazil. Five soil profiles with contrasting source materials (sedimentary and magmatic) were used to evaluate the spectroscopy as a tool capable of identifying changes in the profile during weathering. Soil samples were collected and sent for chemical, physical, mineralogical and spectroscopic analyzes. The proximal sensors analyzes in the laboratory were realized using three sensors, each contemplating a region of the electromagnetic spectrum (x-ray, visible and infrared). In the field, the gamma-ray sensor and the multispectral AISA fênix camera were used to read the entire soil profile developed under sandstone in the spectral regions of visible to shortwave infrared. The elemental, mineralogical and other attributes present in the soil samples collected were evaluated in order to evaluate the weathering intensity of each horizon of the soil profiles. These data were used to describe spectra behavior. The indexes of weathering and the major oxides were quantified from linear and multivariate models using gamma and visible infrared (Vis-IR) data, respectively. The oxides were spatialized in the images of the Fenix AISA sensor for the visual observation of the behavior of the elements and minerals along the profiles. The elemental difference between horizons was calculated from the fluorescence data for comparison with the mass balance calculated by the data provided by the traditional analyzes and the entire spectral region was used separately and together for the segregation of the samples according to with the intensity of weathering. From the behavior of the spectral curves in the region of visible to the medium infrared, it was possible to identify the difference in texture of the horizons, the presence of structural and soil water, the influence of the organic matter and the main minerals that are reflections of the intensity of weathering of each horizon of the analyzed profiles. The data of the GAMA and FRX sensors presented high values of correlation with the oxides and indices used in the quantification of the intensity of weathering, indicating the viability of the sensors for the calculation of the indices. The models for the quantification of the indexes of weathering and oxides presented R² above 0.5. The application of the Vis-IR model to the AISA images allowed quantifying the pixel-to-pixel oxides along the profile and observing the differentiation of the horizons, facilitating the interpretation of the weathering analysis. Due to the specificity of each spectral region to analyze an object, the use of several sensors working at different wavelengths may be an alternative for the faster evaluation of the intensity of weathering occurring in profiles from different source materials.

A Formação Piauí registra a deposição de um sistema eólico, fluvial e marinho raso acumulado em uma bacia de sinéclise intracratônica. A caracterização das associações de fácies e do arcabouço estratigráfico foi feito através de uma descrição detalhada das fácies sedimentares e levantamento de perfis de afloramentos. As fácies foram classificadas de acordo com a textura dos grãos (tamanho e seleção) e estruturas sedimentares observadas. Medidas de paleocorrentes foram feitas nas estratificações e laminações cruzadas. Os perfis foram medidos na escala 1:50 em locais com boa exposição vertical. Seis associações de fácies foram reconhecidas, dunas e interdunas eólicas, lençóis de areia eólicos, canais fluviais, canais fluviais influenciados por maré, shoreface superior e shoreface inferior. Através da correlação das superfícies estratigráficas as associações de fácies foram organizadas em tratos de sistema, que formaram oito sequências deposicionais de alta frequência, delimitados por discordâncias subaéreas. Estas sequências são compostas por um trato de sistemas de nível baixo (TSNB), que é dominado por sistemas eólicos ou fluviais, um trato de sistemas transgressivo (TST), que é formado por canais fluviais influenciados por maré e/ou depósitos de shoreface superior e inferior com empilhamento retrogradacional, e um trato de sistemas de nível alto (TSNA), que é formado por depósitos de shoreface superior e inferior com empilhamento progradacional. Duas sequências deposicionais de mais baixa frequência foram determinadas ao observar o empilhamento das sequências de alta frequência. Ambas as sequências são formadas por uma regressão inicial seguida por uma transgressão progressiva. O principal controle das variações no nível relativo do mar durante a acumulação da Formação Piauí foi glacio-eustático. Contudo, mudanças climáticas estavam associadas com as fases glacio-eustáticas e influenciaram a deposição eólica e fluvial. / The Piauí Formation records the deposition of aeolian, fluvial and shallow marine systems accumulated in a cratonic sag basin. Characterization of the facies associations and sequence stratigraphic framework was done by detailed description of sedimentary facies and logging of outcrops. The facies were classified based on grain texture (size and selection) and sedimentary structures observed. Paleocurrent orientations were measured from cross-strata. Stratigraphic sections were measured at a 1:50 scale at outcrops with good vertical exposure. Six facies associations were recognized: aeolian dunes and interdunes, aeolian sandsheets, fluvial channels, tidally-influenced fluvial channels, upper shoreface and lower shoreface. Through correlation of stratigraphic surfaces the facies associations were organized in system tracts, which formed eight high frequency depositional sequences, bounded by subaerial unconformities. These sequences are composed of a lowstand system tract (LST), that is aeolian-dominated or fluvial-dominated, a transgressive system tract (TST) that is formed by tidally-influenced fluvial channels and/or upper and lower shoreface deposits with retrogradational stacking, and a highstand system tract (HST), which is formed by lower and upper shoreface deposits with progradational stacking. Two low frequency cycles were determined by observing the stacking of the high frequency cycles. Both sequences are formed by an initial regression followed by a progressive transgression. The main control on sedimentation in Piauí Formation was glacioeustasy, which was responsible for the changes in relative sea level. Even though, climate changes were associated with glacioeustatic phases and influenced the aeolian and fluvial deposition.

O mapeamento geológico dos depósitos siliciclásticos aflorantes nas bacias marginais do nordeste brasileiro tem gerado um alto volume de designações estratigráficas ainda abertas às discussões. No intuito de subsidiar a resolução deste problema cartográfico foi escolhida a parte emersa da Bacia Paraíba, mais especificamente as sub-bacias Alhandra e Mirirí. Para isto foi realizada a caracterização mineralógica e petrográfica dos arenitos cenozóicos da Bacia Paraíba, com vistas a identificação de critérios discriminadores entre os diversos depósitos siliciclásticos aflorantes. Derivado deste processo é acrescentado o reconhecimento das áreas fontes desses arenitos e suas implicações na evolução do Cenozóico da Bacia Paraíba. Análises laboratoriais incluíram análises granulométricas, de minerais pesados e morfológica de grãos em 134 amostras de superfície e subsuperfície. Foram estudadas também 5 seções delgadas para testar a petrografia sedimentar como ferramenta no auxílio do mapeamento geológico. A identificação dos minerais pesados transparentes foi feita através microscópio petrográfico, com quantificação dos principais minerais transparentes (100 grãos/lâmina), além de várias contagens independentes (100 grãos/lâmina) das relações transparentes/opacos, do par rutilo/zircão e sobre as formas e grau de arredondamento de zircão e turmalina. Em superfície foram mapeadas como unidades siliciclásticas de base para topo a Formação Barreiras (Mioceno), Depósitos Pós-Barreiras I (Neopleistoceno) e Depósitos Pós-Barreiras II (Holoceno). Em subsuperfície, o furo estudado atravessa toda seção cenozóica e mesozóica, inclusive as unidades basais da bacia, as formações Beberibe e Itamaracá. A mineralogia acessória é dominada por minerais opacos com porcentagens superiores a 60% em todas as unidades. Em toda sucessão cenozóica, as assembléias de minerais transparentes são muito homogêneas e apresentam como minerais principais zircão, turmalina, cianita e rutilo e, subordinadamente, estaurolita, andaluzita, topázio e anfibólios cálcicos. Ocorrem como traços sillimanita, epidoto, monazita e granada. Em subsuperfície, no entanto, na unidade basal é reportada a existência de granada como mineral principal. A análise de formas de zircão e turmalina permitiu diferenciar, tanto em superfície como em subsuperfície, os depósitos estudados. Em termos gerais, existe um maior grau de arredondamento das formas de zircão e turmalina na direção do topo das unidades. Os dados de petrografia, ainda que poucos, apontam diferenças texturais, composicionais e inclusive diagenéticas entre os arenitos aflorantes na bacia. Esta ferramenta mostrou-se promissora para a caracterização das unidades da bacia. A mineralogia acessória em superfície não permite diferenciar as unidades aflorantes, mas, em subsuperfície, mostra que a Formação Beberibe tem uma assinatura de granada que a caracteriza muito bem e permite concluir, de maneira categórica, que esta unidade não aflora na área estudada. Os resultados do estudo de formas em zircão e principalmente em turmalina permitem diferenciar as unidades aflorantes pelo grau de arredondamento dos grãos, o que evidencia uma reciclagem sedimentar inclusive das unidades cretáceas. Este dado é reproduzível em subsuperfície, onde as categorias euédricas concentram-se nas unidades basais. Assim, considera-se que as principais fontes para os depósitos cenozóicos são resultantes do retrabalhamento de unidades sedimentares preexistentes, e subordinadamente, de fontes primárias relacionadas às rochas metamórficas da Zona Transversal da Província Borborema. / The geologic mapping of siliciclastic deposits which outcrop in the marginals basins of Brazilian northeast have generated a high volume of stratigraphic designations that are opened to actual discussions. In order to solve this cartographic problem, the emerging part of the Paraiba basin was chosen, specifically the sub-basins of Alhandra and Mirirí. For this reason were realized the mineralogic and petrographic characterizations of the Cenozoic sands and sandstones of the Paraiba Basin, with the purpose of identifying the discriminating criteria between the diverse siliciclastic deposits. Additionally were realized the recognition of the sandstones´ source areas and its implications in the evolution of the Paraíba Basin in the Cenozoic times. The laboratory analysis included heavy minerals, granulometric, morphology from grains in 134 surface and subsurface samples. Five thin sections were studied to testify the sedimentary petrography as a tool for geological mapping. The identify of heavy minerals was done under petrographic microscope for species descriptions, with counting of 100 grains per slide. Several independent counts (100 grains/slide) of the ratio transparent/opaque, the rutile/zircon index and shape and grain roundness of the zircon and tourmaline were also done. On the geological mapping, the siliciclastic units were considered, from the base to the top, Barreiras Formation (Miocene), deposits Post-Barreiras I (Neopleistocene) and deposits Post-Barreiras II (Holocene). On subsurface, the drill hole studied crosses through the whole Cenozoic and Mesozoic stratigraphy of the basin, including the basal units (Beberibe and Itamaracá formations). The accessory mineralogy is dominated by opaque heavy minerals with higher percentages than 60% in all units. In the whole Cenozoic succession, the assembly of transparent heavy minerals is very homogeneous and is essentially composed by zircon, tourmaline, kyanite and rutile, containing also staurolite, andalusite, topaz and calcic amphibole subordinately. Sillimanite, epidote, monazite and garnet occur as a trace minerals. Otherwise, on subsurface, garnet is reported as a principal mineral in the basal unit. The analysis of zircon and tourmalines shapes allowed to distinguish all the studied deposits. In general, the grade of roundness in grains of zircon and tourmaline increases to the top of succession. The petrografic data showed textural, compositional and diagenetic differences between the cropping out sands - sandstones of the basin. This tool seemed to be a promising to characterize the stratigraphic units of Paraíba Basin. The accessory mineralogy permitted to distinguish the Beberibe Formation, which is well characterized by the presence of garnet. On the other hand, the absence of garnet in the described sandstones let to conclude the Beberibe Formation not exposed in the mapped area. The data from shape studies in grains of zircon and tourmaline allowed to differentiate the cropping out units by the roundness grade, evidencing a sedimentary recycling, including the Cretaceous units. This data is reproducible on subsurface samples where the euedrical categories are concentrated on the basal units. At last, the main sources of the Cenozoic deposits are considered to be reworked preexistence sedimentary units, and subordinately, the primary sources comprise the metamorphic rocks from Transversal Zone of Borborema Province.