A análise das colunas geológicas consultadas a partir de diferentes livros didáticos, possibilitou compreender como o tempo geológico aparece no ensino de evolução, junto à disciplina de biologia do ensino médio e na disciplina de geografia do ensino fundamental, enfocando a origem e as transformações do relevo terrestre ao longo das eras geológicas. Foi possível observar inúmeras informações heterogêneas e problemáticas didáticas, revelando problemas de ordem estrutural e cognitiva, que podem prejudicar professores e alunos no entendimento do tempo profundo, apresentando eventos desorganizados ou omitidos. Procurou-se ressaltar os principais marcos da construção da coluna geológica assim como os principais personagens envolvidos; citando James Hutton, John Playfair, Charles Lyell, Charles Darwin. Responsáveis estes parcialmente pelas modificações do pensamento filosófico-científico da Europa durante os séculos XVIII e XIX, destituindo o antigo pragmatismo dominante da crença de um planeta com 6000 anos de idade. As escalas temporais envolvidas como o mega-intervalo Pré-Cambriano, com 4,0 bilhões de anos de duração ou representando cerca de 85% do tempo geológico, muitas vezes foi apresentado graficamente diminuído ou omitido nas colunas geológicas analisadas. Detectou-se também problemas gráficos visuais com o Eon Fanerozóico, exibindo superdimensionamento das eras e períodos sem nenhuma justificativa aparente, e ressaltando com freqüência, graficamente, a Era Cenozóica com distinto grau de importância, apesar desta apresentar o menor intervalo de tempo registrado na coluna geológica, aproximadamente 65 milhões de anos. A compreensão cognitiva do tempo geológico é complexa e os livros didáticos pouco ajudam seu aprendizado. As evidências fósseis são tomadas como decisivas para a compreensão do tempo geológico. Como parte do trabalho, foram analisadas entrevistas com crianças e adolescentes moradores de jazigos fossilíferos, a fim de compreender como as evidências que lhes são próximas possivelmente influenciaram as idéias que elaboravam sobre o passado do planeta. O trabalho termina discutindo implicações didáticas de diferentes perspectivas. / The analysis of the geologic column consulted from different didatic books hás made possible comprehend how the geologic time appears in the evolution teaching, as a discipline of the biology in the high school, and in the discipline of geography in the school focus in the origin and the transformation of the earth through the geologic era. It was possible to observe uncountable heterogeneous information, and didatic problems, revealing troubles of structural and cognitive order, which difficult teachers and students in the understanding of the deep time, introducing unordered and ommited events. It was highlighted the main steps of the construction of the geologic column as well as the characters involved: citing James Hutton, John Playfair, Charles Lyell, Charles Darwin. These were responsible by the changes of the cientific-filosofic thinking of the Europe during the XVIII and XIX, destroying the old pragmatism of the faith of a planet with 6000 years old. The temporal scales involved with the Pre-Cambrian mega interval, with 4.0 billion years or representing circa 85% of the geologic time, many times was presented graphically shorted or omitted in in the geologic columns revised. It has been detected too graphic troubles with the Eon Fanerozoic, showing over dimensioning of the era and periods without any real motive, and highligting frequently the Cenozoic Era with distinct degree of importance, however it has one of the shortest length in the geologic column, with about 65 million years. The cognitive comprehension of the geologic time is complex and the didatic books softly help your learning. The fossil evidence are considered decisive to the comprehension of the geologic time. As part of the work, it was analyzed some interviews with children and teenagers living near animals and plants fossils samples, to comprehend how the neighborhood evidence could had influence the ideas that made it about the planet past. The manuscript and discussing didatic implications, from different perspectives.

A análise das colunas geológicas consultadas a partir de diferentes livros didáticos, possibilitou compreender como o tempo geológico aparece no ensino de evolução, junto à disciplina de biologia do ensino médio e na disciplina de geografia do ensino fundamental, enfocando a origem e as transformações do relevo terrestre ao longo das eras geológicas. Foi possível observar inúmeras informações heterogêneas e problemáticas didáticas, revelando problemas de ordem estrutural e cognitiva, que podem prejudicar professores e alunos no entendimento do tempo profundo, apresentando eventos desorganizados ou omitidos. Procurou-se ressaltar os principais marcos da construção da coluna geológica assim como os principais personagens envolvidos; citando James Hutton, John Playfair, Charles Lyell, Charles Darwin. Responsáveis estes parcialmente pelas modificações do pensamento filosófico-científico da Europa durante os séculos XVIII e XIX, destituindo o antigo pragmatismo dominante da crença de um planeta com 6000 anos de idade. As escalas temporais envolvidas como o mega-intervalo Pré-Cambriano, com 4,0 bilhões de anos de duração ou representando cerca de 85% do tempo geológico, muitas vezes foi apresentado graficamente diminuído ou omitido nas colunas geológicas analisadas. Detectou-se também problemas gráficos visuais com o Eon Fanerozóico, exibindo superdimensionamento das eras e períodos sem nenhuma justificativa aparente, e ressaltando com freqüência, graficamente, a Era Cenozóica com distinto grau de importância, apesar desta apresentar o menor intervalo de tempo registrado na coluna geológica, aproximadamente 65 milhões de anos. A compreensão cognitiva do tempo geológico é complexa e os livros didáticos pouco ajudam seu aprendizado. As evidências fósseis são tomadas como decisivas para a compreensão do tempo geológico. Como parte do trabalho, foram analisadas entrevistas com crianças e adolescentes moradores de jazigos fossilíferos, a fim de compreender como as evidências que lhes são próximas possivelmente influenciaram as idéias que elaboravam sobre o passado do planeta. O trabalho termina discutindo implicações didáticas de diferentes perspectivas. / The analysis of the geologic column consulted from different didatic books hás made possible comprehend how the geologic time appears in the evolution teaching, as a discipline of the biology in the high school, and in the discipline of geography in the school focus in the origin and the transformation of the earth through the geologic era. It was possible to observe uncountable heterogeneous information, and didatic problems, revealing troubles of structural and cognitive order, which difficult teachers and students in the understanding of the deep time, introducing unordered and ommited events. It was highlighted the main steps of the construction of the geologic column as well as the characters involved: citing James Hutton, John Playfair, Charles Lyell, Charles Darwin. These were responsible by the changes of the cientific-filosofic thinking of the Europe during the XVIII and XIX, destroying the old pragmatism of the faith of a planet with 6000 years old. The temporal scales involved with the Pre-Cambrian mega interval, with 4.0 billion years or representing circa 85% of the geologic time, many times was presented graphically shorted or omitted in in the geologic columns revised. It has been detected too graphic troubles with the Eon Fanerozoic, showing over dimensioning of the era and periods without any real motive, and highligting frequently the Cenozoic Era with distinct degree of importance, however it has one of the shortest length in the geologic column, with about 65 million years. The cognitive comprehension of the geologic time is complex and the didatic books softly help your learning. The fossil evidence are considered decisive to the comprehension of the geologic time. As part of the work, it was analyzed some interviews with children and teenagers living near animals and plants fossils samples, to comprehend how the neighborhood evidence could had influence the ideas that made it about the planet past. The manuscript and discussing didatic implications, from different perspectives.

With the advancements in acquisition and processing of seismic reflection data recorded over crystalline rocks, building three-dimensional geologic models becomes increasingly favorable. Because of little available petrophysical data, interpretations of seismic reflection data in hardrock terrains are often speculative. Potential field data modeling are sometimes performed in order to reduce the ambiguity of seismic reflection interpretations. The Kristineberg mining area in the western part of the Paleoproterozoic Skellefte Ore District was chosen to construct a pilot three-dimensional geologic model in an attempt to understand the crustal architecture in the region and how the major mineral systems operated in this architecture. To contribute to this aim, two parallel seismic reflection profiles were acquired in 2003 and processed to 20 sec with special attention to the top 4 sec of data. Several reflections were imaged and interpreted by the aid of reflector modeling, borehole data, 2.5D and 3D potential field modeling, and geological observations. Interpretations are informative at the crustal scale and help to construct a three-dimensional geologic model of the Kristineberg mining area. The three-dimensional geologic model covers an area of 30×30 km2 down to a depth of 12 km. The integrations help to interpret a structural basement to the Skellefte volcanic rocks, possibly with Bothnian Basin metasedimentary affinity. The contact is a shear-zone that separates the two units, generating large fold structures, which can be observed in the region. The interpretations help to divide the Revsund granitic rocks into two major groups based on their present shape and thickness. A large gravity low in the south is best represented by the intrusion of thick dome of Revsund granite. In the north, the low-gravity corresponds to the intrusion of sheet-like Revsund granites. In general, the structure associated with the Skellefte volcanics and the overlying metasedimentary rocks are two thrusts exposing the Skellefte volcanic rocks in the cores of hanging wall anticlinal structures. Lack of coherent reflectivity in the seismic reflection data may be due to complex faulting and folding systems observed in the Skellefte volcanics. Ultramafic sills within the metasedimentary rocks are interpreted to extend down to depths of about 5-6 km. The interpretations are helpful for targeting new VHMS deposits and areas with gold potential. For VHMS deposits, these are situated in the southern limb of a local synformal structure south of the Kristineberg mine, on the contact between the Revsund granite and the Skellefte volcanic rocks. A combination of metasedimentary and mafic-ultramafic rocks are highly gold prospective in the west, similar to observations elsewhere in the region. There are still questions that remain unanswered and need more work. New data in the study area will help to answer questions related to e.g., an enigmatic diffraction seismic signal in Profile 5 and the structural relationship between the Skellefte volcanic rocks and the Malå volcanics. Although the derived 3D geologic model is preliminary and constructed at the crustal scale, it provides useful information to better understand the tectonic evolution of the Kristineberg mining area.

Antes de se fazer uma estimativa ou uma simulação geoestatística, os domínios geológicos devem ser modelados de forma que cada domínio utilize apenas dados que pertencem a ele. Na industria mineral a incerteza oriunda dos teores geralmente é levada em consideração, entretanto a incerteza gerada pelo modelo nem sempre é analisada. Sabendo que a maior fonte de incerteza está na transição de uma litologia para outra, essa dissertação visa avaliar a incerteza do modelo geológico através de simulações de funções distâncias assinaladas em zonas de maior incerteza, gerando vários modelos com diferentes proporções de cada litologias. Um estudo de caso em um banco de dados real com alta complexidade geológica é utilizado para avaliar o uso da metodologia. O método se mostrou eficaz para avaliar o impacto da diferença de volume que cada litologia pode alcançar, demonstrando a importância de medir a incerteza na construção de modelos geológicos. / Before making an estimation or a geostatistical simulation, geological domains must be modeled so that each domain uses only data that belongs to it. In the mineral industry the uncertainty derived from the grades is generally taken into account, however the uncertainty generated by the model is not always analyzed. Knowing that the greatest source of uncertainty is in the transition from one lithology to another, this dissertation aims to evaluate the uncertainty of the geological model through signed distances function simulation in uncertainty zones, generating several models with different proportions of each lithology. A case study in a real dataset with high geological complexity is used to evaluate the use of the methodology. The method proved effective in assessing the impact of the volume difference that each lithology can reach, demonstrating the importance of measuring uncertainty in the construction of geological models.

Ao modelar-se depósitos minerais é comum enfrentarmos o problema de estimar múltiplos atributos possivelmente correlacionados, onde algumas variáveis são amostradas menos densamente do que outras. A falta de dados impõe um problema que requer atenção antes de qualquer modelagem subsequente. Precisamos, ao final, de modelos que sejam estatisticamente representativos. A maioria dos conjuntos de dados de problemas práticos são amostrados de maneira heterotópica e, para obter resultados coerentes, é preciso entender os motivos pelos quais alguns dados faltam e quais são os mecanismos que influenciaram a ausência de informações. A teoria de dados faltantes relaciona as amostras ausentes com aquelas medidas através de três mecanismos distintos: Faltante Completamente Aleatório (Missing Completely At Random - MCAR), Faltante Aleatório (Missing At Random - MAR) e Faltante Não Aleatório (Missing Not At Random - MNAR). O último mecanismo é extremamente complexo e a literatura recomenda ser tratado inicialmente como um mecanismo MAR. E após uma transformação fixa deve ser aplicada aos valores complementados para que estes se transformem em valores MNAR Embora existam métodos estatísticos clássicos para lidar com dados faltantes, tais abordagens ignoram a correlação espacial, uma característica que ocorre naturalmente em dados geológicos. A metodologia adequada para tratar com a falta de dados geológicos é a atualização bayesiana, em que se inserem valores sob mecanismo MAR considerando a correlação espacial. No presente estudo, a atualização bayesiana foi combinada com transformações fixas para tratar o mecanismo de falta de dados MNAR em dados geológicos. A transformação fixa aqui empregada é baseada no erro de inserção gerado em um cenário MAR no conjunto de dados. Assim, com o conjunto completo resultante foi utilizado em uma simulação sequencial gaussiana dos teores de uma base de dados multivariada, apresentando resultados satisfatórios, superiores aos obtidos por meio da cossimulação sequencial gaussiana, não inserindo qualquer viés no modelo final. / When modeling mineral deposits, it is common to face the problem of estimating multiple attributes possibly correlated where some variables are more densely sampled then others. Missing data imposes a problem that requires attention prior to any subsequent modeling. The later requires estimation models statistically representative. Most practical data sets are often heterotopically sampled, and to obtain coherent results one must understand the reasons why there are missing data and what are the mechanisms that cause the absence of information. The theory of missing data relates the missing samples to those measured through three different mechanisms: Missing Completely At Random (MCAR), Missing At Random (MAR), and Missing Not At Random (MNAR). The last mechanism is quite complex to deal with, and the literature recommends being treated as a MAR mechanism and after a fixed transform should be applied to the imputed values so that these turn into MNAR imputed values. Even though there are classical statistical methods to deal with missing data, such approaches ignore spatial correlation, a feature that occurs naturally in geological data. The adequate methodology to deal with missing geologic data is Bayesian Updating, which approaches the MAR mechanism and accounts for spatial correlation. In the present study, bayesian updating was used combined with fixed transforms to treat MNAR missing data mechanism in geologic data. The fixed transform herein used is based on the error of MAR imputation on the data set. The resulting complete set was then used on a sequential gaussian simulation of the grades on a multivariate data set, presenting satisfactory results, superior to those obtained through sequential gaussian cossimulation, not inserting any biases on the final model.

The age of the Bridgerian/Uintan boundary has been regarded as one of the most important outstanding problems in North American Land Mammal “Age” (NALMA) biochronology. The Bridger Basin in southwestern Wyoming preserves one of the best stratigraphic records of the faunal boundary as well as the preceding Bridgerian NALMA. In this dissertation, I first developed a chronological framework for the Eocene Bridger Formation including the age of the boundary, based on a combination of magnetostratigraphy and U-Pb ID-TIMS geochronology. Within the temporal framework, I attempted at making a regional correlation of the boundary-bearing strata within the western U.S., and also assessed the body size evolution of three representative taxa from the Bridger Basin within the context of Early Eocene Climatic Optimum. Integrating radioisotopic, magnetostratigraphic and astronomical data from the early to middle Eocene, I reviewed various calibration models for the Geological Time Scale and intercalibration of 40Ar/39Ar data among laboratories and against U-Pb data, toward the community goal of achieving a high precision and well integrated Geological Time Scale. In Chapter 2, I present a magnetostratigraphy and U-Pb zircon geochronology of the Bridger Formation from the Bridger Basin in southwestern Wyoming. The ~560 meter composite section spans from the lower Bridger B to the Bridger E, including the Bridgerian/Uintan NALMA boundary in the uppermost part of the section. Analysis of samples from 90 sites indicates two paleomagnetic reversals that are correlated to an interval spanning Chrons C22n, C21r, and C21n by comparison to the Geomagnetic Polarity Time Scale (GPTS). This correlation places the Bridgerian/Uintan faunal boundary within Chron C21n, during the initial cooling phase following the peak of the Early Eocene Climatic Optimum. Based on the bio- and magnetostratigraphic correlation, I provide correlation of other Bridgerian/Uintan boundary-bearing sections to the GPTS, demonstrating that in the western North America, the Bridgerian/Uintan boundary occurs everywhere in Chron C21n. In addition, U-Pb zircon geochronological analyses were performed on three ash beds from the Bridger Formation. High-precision U-Pb dates were combined with the paleomagnetic polarity data of the same ash beds as well as the integrative chronostratigraphy of the basin to assess prior calibration models for the Eocene part of the GPTS. The data from the Bridger Formation indicate that the Option 3 age model of Westerhold et al. (2008) best reconciles the geochronological data from all of the ash beds except for one. Thus I favor this Option 3 model, which indicates the ages of 56.33 Ma and 66.08 Ma for the Paleocene-Eocene Thermal Maximum and Cretaceous/Paleogene boundary, respectively. In Chapter 3, the body size evolution of three mammalian taxa from the Bridgerian NALMA was analyzed within the context of Bergmann’s Rule, which poses a correlation between the size of endotherms and climate (latitude). The Bridgerian NALMA is from a time of global cooling following the peak of the Early Eocene Climatic Optimum, thus according to Bergmann’s Rule, the Bridgerian mammals are expected to increase in size. This hypothesis is tested among Notharctus, Hyopsodus, and Orohippus, using the size of molar dentition as a proxy for their body size. These taxa represent three different ecomorphs, and I investigated if these taxa showed a pattern of body size change consistent with the prediction made by Bergmann’s Rule, and how their ecological adaptation may have affected their response to the climate change. Prior to analyzing the body size evolution, specimens of Notharctus and Hyopsodus were identified to species based on dental characters. This practice differs from previous studies in which species identification relied on relative size of the individuals and stratigraphic levels of origin. Within the new framework of morphologically determined species identification, five species of Notharctus were recognized, among which, N. pugnax, N. robustior and N. sp. indet. exhibited statistically significant body size increase in the time span of interest. Based on morphological analyses of Hyopsodus dentition, I recognized five species. Dentition-based body size analysis showed that H. lepidus and H. despiciens exhibited a statistically significant change towards larger size within the sampled interval. When analyzed at the generic level, a statistically significant increase was observed for both Notharctus and Hyopsodus. Finally, a genus-level analysis of Orohippus showed a lack of statistically significant size increase over the study interval. Thus, among the three taxa from the Bridgerian, Bergmann’s Rule is supported by Notharctus and Hyopsodus, at least at the genus level, but not by Orohippus, although the patterns are more variable at the intraspecific level. In Chapter 4, 40Ar/39Ar dates were obtained from sanidines from the middle Eocene Henrys Fork tuff and Upper Carboniferous Fire Clay tonstein, with the goal of making highly precise measurements of these two samples, keyed to the Fish Canyon monitor standard. Analytically, both samples were well characterized, as had been shown previously. The irradiation disk was arranged such that there would have been control from the Fish Canyon surrounding each of the unknown pits. However, due to several complications in the lab during the course of the experiment, only the analyses from one run disk (Disk 677) were of the quality needed for the goals of the study. As a result, the Fish Canyon sanidine standards that were irradiated near the center of the irradiation disk had to be discarded, and thus, the neutron fluence could not be mapped out precisely across the entire disk. The 40Ar/39Ar age relative to Fish Canyon sanidines is 47.828 ± 0.205 Ma and 311.937 ± 1.282 Ma for the Henrys Fork tuff and Fire Clay tonstein, respectively (1σ, including error on the age of the monitor). Because the ages were both offset about the same amount, I explored the option of using the U-Pb ID-TIMS ages of the Henrys Fork tuff and Fire Clay tonstein to test the agreement in the chronometers. The Henrys Fork tuff was dated at 48.260 ± 0.107 Ma (1σ, including error on the age of the monitor) using the Fire Clay sanidines and assuming its age is the U-Pb zircon age. The Fire Clay tonstein was dated at 314.593 ± 0.699 Ma (1σ, including error on the age of the monitor), using the Henrys Fork sanidines and assuming its age is the U/Pb zircon age. Although the complications encountered render these data unpublishable, they show great promise as the ages of each sanidine sample, tied to the other ash using the other ash’s U-Pb age, give results that are in close agreement between the two chronometers on the same sample (e.g., 314.593 ± 0.699 Ma vs. 314.554 ± 0.020 Ma at 1σ for sanidine and zircon respectively from the Fire Clay tonstein, and 48.260 ± 0.107 Ma vs. 48.265 ± 0.008 Ma 1σ for sanidine and zircon respectively from the Henrys Fork tuff).

Northern Africa has experienced major shifts towards aridity and extensive C4 vegetation over the late Cenozoic, but due to a scarcity of spatially and temporally extensive paleoenvironmental records, the timing, patterns, and causes of these shifts are still under debate. Both long-term aridification and large amplitude orbital-scale climate variability have been recognized, with little understanding of how these two patterns relate to each other over time. African’s climate and environmental history of the last 7 Myr is of particular interest because hydrological and vegetation variability is considered the driving selection mechanism for human evolution. In addition, the age of the initiation of desert conditions in the modern Sahara desert, Earth’s largest warm desert and the largest source of dust to the modern atmosphere, is unknown. The stable isotope ratios of carbon and hydrogen in sedimentary plant leaf wax biomarker compounds have recently been shown to quantitatively track source vegetation photosynthetic pathways and the hydrogen isotope composition of plant source water, which is dominantly controlled by the amount of precipitation in Africa. These proxies have been applied to reconstruct long-term vegetation changes in East Africa and SW Africa over the last 14 Ma, as well as orbital-scale variability from various locations around the African continent, but they have not been extended further back in time or combined in tandem to robustly assess both long-term and orbital-scale climate and vegetation variability and how they relate to each other. In this thesis, I have utilized quantitative plant leaf wax stable isotope proxies to examine both orbital-scale and long-term changes in North African aridity and vegetation from a variety of regions over the last 25 Ma, with particular emphasis on the last 4.5 Ma. In Chapter 2, I investigated the evolution of hydrological and vegetation gradients from the equator to the sub-Sahara in NW Africa over the last 25 Myr using leaf wax stable isotopes at two marine sediment core locations, producing the longest existing leaf wax stable isotope record in Africa to my knowledge, and one of the longest such records globally. In this study I found that NW African environments were remarkably similar at both latitudes from 25 – 10 Ma, but at 10 Ma C4 vegetation abruptly expanded in the north, indicating sudden aridification in the Sahara region at that time. The hydrogen isotope record was stable long-term, with variability similar to that of known orbital-scale cyclicity in the Pliocene and Pleistocene, possibly suggesting that orbital-scale cyclicity or other factors obscured or were larger than any long-term changes in the hydrogen isotope ratio of precipitation. Saharan aridification at 10 Ma is consistent with climate model predictions of aridity due to the closure of the Tethys Seaway connection between the Indian Ocean and Mediterranean Sea near that time. The 10 Ma expansion in C4 vegetation is earlier than most other regions globally. To examine long-term changes in orbital-scale variability in the Eastern Sahara and Mediterranean Sea, I constructed a record of eastern Mediterranean sedimentary leaf wax carbon and hydrogen isotopes, leaf wax abundance, lignin biomarkers, and oxygen isotope ratios of planktonic foraminifera G. ruber during two 100-kyr periods of equal eccentricity near 3.0 and 1.7 Ma (Chapter 3). I found that precession-scale variability dominates the record during both periods, and Eastern Saharan precipitation and the vegetation assemblage, which was C4-dominated, do not change on average between the two periods. Chapter 4 extended the eastern Mediterranean record of Chapter 3 by sampling leaf wax stable isotopes in sapropel sediments (deposited during North African humid periods) at ~0.25 Myr resolution back to 4.5 Ma, placing the orbital-scale Chapter 3 results in long term context. I found that Eastern Saharan environments were persistently C4-dominated (>68%) throughout the entire interval, and that long-term hydrogen and carbon variability were similar in magnitude to orbital-scale cycles back to 4.5 Ma, strongly indicating that orbital-scale variability has been the dominant environmental control in NE Africa since the early Pliocene. This record contrasts sharply with observations of a transition from C3-C4 mixed vegetation to abundant C4 grasslands in East Africa over the same period of time. The results may suggest that long-term precipitation shifts did not occur in NE Africa since the Pliocene, or that the resolution of this approach is not sufficient to detect long-term shifts. It is likely that NW Africa also experienced similarly large hydrological variability over the same period of time, which may explain the unclear long-term hydrological signal in Chapter 2. The results emphasize that East Africa has not been representative of northern Africa as a whole since the Pliocene.

The Golden Throne Quadrangle is located within Capitol Reef National Park, south-central Utah. Geologic mapping of this 1:24,000 scale 7.5 minute quadrangle began in 2003 as the National Parks Service desired to have geologic maps at this scale produced within the park. Stratigraphically, ten bedrock formations and ten Quaternary deposits are exposed within the Golden Throne Quadrangle. Geologic formations range in age from Permian to Jurassic. This map contains details not included on previous geologic maps including; the members of the Carmel, Chinle, and Moenkopi Formations. Additionally, the Page Sandstone is herein mapped as an independent unit. Structurally the Golden Throne Quadrangle encompasses most of the southern quarter of the Miners Mountain uplift. The crest of this southwest verging uplift is cut by the left-lateral strike-slip Teasdale Fault zone. Preparation of a cross-section through the axis of the uplift within the quadrangle has not permitted the use of usual faulting and folding mechanisms (i.e. fault-bend folds and fault-propagation folds) for the creation of the uplift. Two structural models can account for the geometries observed in the field. The first model is a high angle reverse basement fault; the second model is a fold over an inverted basin. The Jurassic Page Sandstone, in the Golden Throne Quadrangle, is composed of the Harris Wash and Thousand Pockets Members, which are divided by the Judd Hollow Tongue, a member of the overlying Carmel Formation It represents an erg deposit and is primarily composed of eolian sandstone. Study of the formation within the Golden Throne Quadrangle helped in the understanding of its local characteristics. Previous research has helped to develop a regional stratigraphic framework for the Page Sandstone. This study cannot be easily incorporated into the regional framework of previous studies. In order to fully understand the sedimentology of the Page Sandstone additional research will need to be accomplished.

Abstract Crater counting is a method which allows us to estimate the surface ages of the planetary bodies, from which the sampling and sample delivery to laboratories on Earth are difficult or impossible. Because the number of craters on a surface unit increases over the time the surface has been exposed to space, old, geologically stable units have more craters than young and active units. When the crater production rate as a function of time is known, the absolute age of the surface unit can be determined based on its crater density. The purpose of this thesis is to investigate the role of small impact craters in crater counts to find out how modern very high-resolution space images can be utilized in age determination of planetary surfaces. The thesis focuses on how reliable crater count based datings are, if only small craters and counting areas are used in age determination. The research is carried out by utilizing crater counts on the outflow channels of Dao, Niger, Harmakhis and Reull Valles, which all are located in the eastern rim region of the Hellas impact basin, on the southern hemisphere of Mars. Crater counts are performed mainly based on the images of ConTeXt Imager (CTX) and High Resolution Imaging Science Experiment (HiRISE) aboard Mars Reconnaissance Orbiter (MRO). The results show that small craters are a very valuable tool to get information about the surface age. Instead of the size-range of counted craters, or the size of counting areas, results are dependent on the variability and scale of the surface modification history. The more variable or larger scale the modification history is, the larger surface area and wider crater diameter range are typically needed to achieve comprehensive age estimations. The crater counts on the eastern Hellas outflow channels support the earlier theories according to which the valles formed during a relatively short time interval, ~ 3.4–3.7 Ga ago. The existence of terrace structures and smaller tributary channels indicate that the outflow channels were filled by several pulses of liquids. The major fluvial activity ended no later than ~ 0.8–1.9 Ga ago, and it was probably controlled by the activity of nearby highland volcanoes. Soon after the declined fluvial activity, the outflow channels were covered by ice-rich deposits. The major reason for this was probably the changed climatic conditions, although in places e.g. impact cratering seems to have contributed to the emplacement of the deposits. The region as a whole was also resurfaced several times because of changes in local climate conditions. The most significant of the resurfacing processes seem to be the episodes of thin ice-rich mantling deposits, the most recent of which dominated the regional modification less than 10 Ma ago. In addition, the region has experienced eolian activity during the last 1 Ma. / Original papers The original publications are not included in the electronic version of the dissertation. Kostama, V.-P., Kukkonen, S., & Raitala, J. (2017). Resurfacing event observed in Morpheos basin (Eridania Planitia) and the implications to the formation and timing of Waikato and Reull Valles, Mars. Planetary and Space Science, 140, 35–48. https://doi.org/10.1016/j.pss.2017.04.001 Kukkonen, S., & Kostama, V.-P. (2018). Modification history of the Harmakhis Vallis outflow channel, Mars, based on CTX-scale photogeologic mapping and crater count dating. Icarus, 299, 46–67. https://doi.org/10.1016/j.icarus.2017.07.014 Kukkonen, S., & Kostama, V.-P. (2018). Usability of small impact craters on small surface areas in crater count dating: Analysing examples from the Harmakhis Vallis outflow channel, Mars. Icarus, 305, 33–49. https://doi.org/10.1016/j.icarus.2018.01.004 Kukkonen, S., & Kostama, V.-P. (2018). Mapping and dating based evolution studies of the Niger Vallis outflow channel, Mars. Planetary and Space Science, 153, 54–71. https://doi.org/10.1016/j.pss.2017.12.012 Korteniemi, J., & Kukkonen, S. (2018). Volcanic Structures Within Niger and Dao Valles, Mars, and Implications for Outflow Channel Evolution and Hellas Basin Rim Development. Geophysical Research Letters, 45(7), 2934–2944. https://doi.org/10.1002/2018gl077067 http://jultika.oulu.fi/Record/nbnfi-fe201902226008

Important public facilities located in Cache Valley, Utah, were studied to assess their exposure to geologic hazards. Also, the level of geotechnical and geologic expertise involved in the siting, design, and construction of critical public facilities was studied. A discussion of several individual facilities, that were exposed to some degree of hazard, was presented to illustrate the nature of the problem. Earthquake hazards probably constitute the greatest threat to facilities and to the general welfare of the public. Many earthquake hazard mitigation measures were discussed and recommendations were made, based on aseismic design criteria which has been developed for seismically active areas such as California. A goal of this study was to present information concerning the seriousness of the current geologic hazard situation in Cache Valley, Utah, in an attempt to help generate public interest in understanding and correcting the problem.