Microbes are prevalent in geologic settings and a growing body of research suggests the roles they play in geologic processes may be more important than previously thought, and therefore underestimated. This dissertation addresses the influence of microbes on the dissolution of limestone in karst settings by analyzing the stable carbon isotopes and geochemistry of air and waters from three unique cave and karst settings: West-Central Florida, the Everglades (southern Florida) and The Bahamas. In Florida, these parameters as well as air/water temperature, rainfall, and water-level fluctuations were monitored for 22 and 10 months. In the Bahamas, geochemical data were collected from at varying time-intervals from a variety of cave and surface water bodies. Results showed that microbial respiration in these environments is an important source of carbon dioxide, which contributes to the formation of carbonic acid, which appears to be the major dissolving agent at each of these sites. At the same time, microbially-mediated oxidation of both organic matter and minerals exerts a secondary dissolution control by providing additional acid and inorganic ions that dissolve rock and/or inhibit limestone precipitation. This dissertation also includes a chapter discussing the role of the USF Department Geology in the evolution of assessment for Spreadsheets Across the Curriculum (SSAC) project, which promotes quantitative literacy (QL) by teaching math in the context of other disciplines. Assessment occurred primarily in the Computational Geology course from 2005 to 2008 and showed that this teaching strategy fostered gains in math knowledge and positive math association. Simultaneously, instructors learned that pre-planning and adaptability was central to developing a successful assessment strategy, which, when combined with the heterogeneity of subjects each year, presents challenges in the yearly comparison of results. These conditions are common in educational settings, illustrating the impracticality of standardized assessment instruments and practices, and the importance of the extensive preparation required in identifying assessment goals and the best strategies for achieving them in a given setting.

Microbial communities influence the kinetics and pathways of reactions involved in the dissolution of a number of minerals (Ehrlich 1996). On a smaller scale these interactions can affect substrate permeability, porosity, and create highly localized biogeochemical conditions. However, a mechanistic understanding of the consequences of microbial surface colonization on calcite dissolution rate has yet to be achieved. More specifically, little is known about the impact of sulfur-oxidizing bacteria activity on the rate of carbonate mineral dissolution, or the nature of the microbe-limestone attachment and interaction. Through a series of laboratory and field experiments the effect of mineral surface colonization by microbial communities, obtained from an active sulfuric acid cave (Lower Kane Cave (LKC), Big Horn Basin, WY), on the dissolution rate of Madison Limestone was quantified. Results from laboratory experiments showed that a microbial biofilm, composed primarily of Epsilonproteobacteria and Gammaproteobacteria growing on a limestone surface oxidized thiosulfate and increased carbonate dissolution rates up to 3.3 times faster than abiotic rates. When all thiosulfate substrate was withheld the community oxidized stored intracellular sulfur, continuing to accelerate limestone dissolution and decreasing pH. This process is sensitive to O2 limitations. Characterization of this aggressive sub-biofilm corrosion was more closely examined by SEM imaging. By comparing mineral surface morphology of colonized chips to non-colonized chips of various carbonate substrates, it was shown that even under conditions near equilibrium with calcite, aggressive dissolution of carbonate substratum occurs exclusively beneath the biofilm. These findings support the hypothesis that (1) sulfur-oxidizing microbial communities aggressively dissolve carbonates in order to buffer the production of excess acidity by neutrophilic communities and (2) biofilm presence affects carbonate mineral dissolution by physically separating a bulk stream water from the sub-biomat environment. Furthermore, it was found that mineralogy affects the degree of establishment of microbial communities in this environment. Results from a series of four laboratory and one in situ reactor experiment showed that limestone and dolostone substratum consistently had higher biomass accumulations than silicate minerals or pure Iceland spar calcite in the same reactor. These results provide evidence to support the hypothesis that mineralogy influences microbial accumulation in sulfuric-acid karst systems. Particularly, neutrophilic sulfur-oxidizing communities accumulate in greater quantities on solid substrates that buffer metabolically-generated acidity. These results also demonstrated the dependence of microorganisms on colonization of a particular mineral surface, possibly in order to gain access to micronutrients bound within solid substrates when exposed to nutrient-limited conditions. / text

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Η παρούσα Διπλωματική εργασία επικεντρώνεται στη γεωλογική και πετρογραφική μελέτη των ασβεστολιθικών πετρωμάτων της Ανατολικής Καβάλας. Σκοπός είναι η απόκτηση νέων πληροφοριών για καλύτερη εκτίμηση και χρήση αυτών των ασβεστολιθικών πετρωμάτων ως αδρανή υλικά σε κατασκευαστικές αλλά και περιβαλλοντικές εφαρμογές. / This thesis focuses on geological and petrographic study of the limestone rocks of eastern Kavala. The aim is to gain new information to better assess and use these calcareous rocks as aggregates in construction and environmental applications.

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The Middle Devonian formations to be studied in this paper are the Jeffersonville and North Vernon Limestones. Together these formations make up the Muscatatuck Group in the Illinois Basin portion of Indiana. In the area of study, the Jeffersonville Limestone consists from the base upwards of the Geneva Dolomite Member, Vernon Fork Member, and Paraspirifer acuminatus Zone. The North Vernon Limestone consists of the Speed Member overlain by the Beechwood Member.In the study area, the subsurface Muscatatuck Group dips to the southwest at a rate of 20 to 50 feet per mile. These rocks thicken to the southwest, and range in thickness from 136 to 170 feet. Closed-structural highs are present on the top of the Muscatatuck Group over Silurian pinnacle-like reefs.Resistivity log - sonic log cross plots were constructed to analyze the subsurface carbonate facies in the study area. A total of 13 cross plots were constructed with over 1,490 points plotted.From this study five conclusions can be drawn about the application and usefulness of the cross plot method in analyzing the the surface distribution of carbonate facies. As explained in the text, these conclusions remain valid only when applied to the area of study.The conclusions are as follows:1. The positioning of the point groups on the cross plots is controlled by the amount and type of porosity present in the rocks.2. Due to the diagenetic alteration of the primary porosity in the rocks, the point groups can not be divided into depositional textures or facies.3. In this case, because of the uncomplex nature of the stratigraphy and the ease of correlation of the lithologic units on the logs, the cross plots were not useful in analyzing the subsurface distribution of the carbonate facies in the area.4. The cross plots were useful in checking the accuracy of the log correlations.5. The cross plots may be used to infer lateral porosity changes in the rock units, and possibly variations in the diagenetic alteration within these units.

Portland-limestone cements (PLC) have been used in practice for a considerable period of time in several countries. In 2008, the CSA A3000 cements committee approved the addition of a new class of cement with up to 15% interground limestone. The CSA A23.1 concrete committee also approved the use of PLC in concrete in 2009. However, to date, due to uncertainty about the performance of Portland-limestone cements in sulfate environments, their use has not been allowed in sulfate exposures. In this study, the sulfate resistance of five different Portland-limestone cements and their combinations with various amounts of supplementary cementitious materials (SCMs) were examined. Besides the standard tests performed at 23 °C, a modified version of the ASTM C1012 test was developed in this study (adopted in 2010 as CSA A3004-B) and used to investigate the possibility of thaumasite form of sulfate attack at 5 °C. It was found for tests conducted at 23 °C that while 100% cement mixes deteriorated in sulfate exposure due to conventional sulfate attack, partially replacing the Portland cements and Portland-limestone cements with 30% or 50% slag was effective in making the mixes highly sulfate-resistant. In sulfate exposure at 5 °C, all of the 100% cement mortar bars failed the test and had completely disintegrated due to the formation of thaumasite. Partially replacing cement with 30% slag was effective in controlling the deterioration at 5 °C only for Portland cements and not Portland-limestone cements. However, all the combinations of the cements with 50% slag were resistant to the thaumasite form of sulfate attack. In a parallel study, the hydration of Portland-limestone cements and the relationship between strength and porosity of mortar samples were examined. The results of hydration studies revealed that the limestone portion of Portland-limestone cements reacts with the alumina phases and produces carboaluminates, which contributes to the strength. As the limestone content of the cement increased, the shift in the optimum level of SCM providing maximum strength and minimum porosity was attributed to the availability of more alumina, which allowed more limestone to participate in the hydration reactions, forming additional carboaluminate hydrates.

Due to rapidly growing population of Ankara city (Turkey) and traffic load, it is required to widen some of the existing highways. One of them is Ankara-EskiSehir (E-90) highway that connects highly populated areas to the city center. During widening, several cut slopes were formed along the highway route. However, some instability problems such as small-sized rock falls and rock detachments have occurred along a cut slope in highly jointed, folded and sheared limestone. They caused local degradation of the cut slope. The cut slope has a slope angle varying from 71&deg / to 84&deg / and contains several shear zones. In this study, the relationships between the existing detachment zones and various parameters (e.g. block size, point load strength index, weathering, shear zone, daylight zone) considered to be important for slope instability were investigated using GIS-based statistical landslide susceptibility analyses in order to predict the further aerial extension of the detachment zones with time. During the overlay analyses, statistical index and weighting factor methods were used by means of TNT-MIPS software. The outcomes of the analyses using both methods are compared and evaluated together with the field observations to check the reliability of the methods and to assess the detachment zones that may develop in the future. Additionally, limit equilibrium analyses were also carried out for the determination of the possible large scale mass failures. The overlay analyses indicate some risky zones where detachments are likely to occur in the future. On the other hand, the limit equilibrium analysis of the rock mass using Bishop simplified method shows that except one section no mass failure is expected in the cut slope. Suitable remediation measures which include the use of wire mesh, shotcrete, toe support, and concrete barrier blocks or catch/barrier fences are recommended for these zones.

This thesis reports the results obtained, and conclusions made regarding research into the hydrochemistry of a small impounded karst area in southeastern Australia. Water samples were collected from a variety of sites over a period of approximately six years and include samples that are representative of baseflow (drought conditions) and flood (high flow conditions) the two extremes of the flow regime. Four distinct water types were found to be associated with the karst spring and cave water sites sampled. In terms of physical, chemical and computed parameter values these have been classed as TYPE 1 water (median parameter values similar to those noted for the surface stream sites sampled with catchments of non-carbonate material); TYPE 2 water (catchment predominantly of limestone); TYPE 3 water (catchment predominantly of dolomite); TYPE 4 water (high median chemical concentrations). Spatial variation within the study area is considerable and intrinsic factors such as catchment lithology, the residence time of recharge, aspect and vegetation cover are the major natural controls in determining physical and chemical characteristics.