Browsing by Author "Sutton, Sally, advisor"
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Item Open Access Changes in water chemistry and fluvial geomorphology from arsenic contaminated floodplains of Whitewood Creek and Belle Fourche River, South Dakota(Colorado State University. Libraries, 2023) Marr, Alexander E., author; Sutton, Sally, advisor; Ridley, John, advisor; Ross, Matthew, committee memberFrom 1877 to 1977 the Homestake Gold Mine in Lead, South Dakota released over 100 million megagrams (Mg) of arsenic rich mine waste into Whitewood Creek which joins the Belle Fourche River. The mine waste which contains arsenopyrite and other arsenic bearing minerals, is deposited along the floodplains of Whitewood Creek and the Belle Fourche River as overbank deposits and abandoned meander and channel fill. The introduction of mine tailings into these streams has impacted them chemically and geomorphologically for over 100 years. This study is a continuation of the work from Ji (2021) who focused on the long-term behavior of arsenic in the mine tailings. Her work involved sequential extractions of the tailings to determine the mineralogical setting of the arsenic and its rate of release. She also used statistical regression on historical data to estimate the physical and chemical removal of arsenic from Whitewood Creek's watershed. The focus of this study is to see how the tailings might have impacted the stream chemistry of Whitewood Creek and the Belle Fourche River by modeling mineral saturation indices of the stream and seep water through the geochemical modeling program, The Geochemist's Workbench. The Geochemist's Workbench was used to model the dissolution rate of arsenopyrite to calculate the rate of dissolved arsenic entering Whitewood Creek. Suspended arsenic entering Whitewood Creek was calculated using the dimensions of the creek bed, thickness of tailings, and density of arsenopyrite. In addition to chemistry, this study investigated the changes in the tailings and fluvial geomorphology of Whitewood Creek and the Belle Fourche River from 1948 to 2012. This was performed by using aerial photographs from 1971, which mapped locations of the tailings along the floodplains, and overlaying them with photographs from 1948, 1977, and 2012. Using GIS through ArcMap, the tailings and their portions that have been removed over time were digitized. Other fluvial parameters that have been determined and digitized are stream longitudinal profiles, sinuosity, contaminated floodplain width, channel migration, and total sediment deposition area. The mineral saturation indices of Whitewood Creek and the Belle Fourche River are similar to each other and differ at the most by around 2-3 orders of magnitude. The minerals that are supersaturated are mainly phyllosilicates (mostly clays), Fe, Cu and Al (hydr)oxides, and carbonates with minor sulfates and phosphates. Seep waters have lower mineral saturation indices, up to 10 orders of magnitude lower for Fe bearing minerals. The only arsenic bearing mineral that is calculated to be supersaturated is Ba3(AsO4)2; however, this mineral has not been observed in nature. Based on the range of possible arsenopyrite concentration in the contaminated sediment (15 to 0.11%), the calculation of dissolved arsenic being discharged out of Whitewood Creek ranges from 52 to 0.39 Mg per year. This range compares to Ji's (2021) daily dissolved arsenic rate range of 3.89-0.33 Mg/year. For a tailings width range of 0.6 to 3.5 m, the calculated rate of suspended arsenic being discharged ranges from 254 to 1.98 Mg per year. Although large, this range encompasses Ji's (2021) suspended arsenic transport rate range of 33 to 70 Mg per year. The overlap of values from Ji's (2021) statistical approach and this study's geochemical approach indicates that arsenopyrite may be to some degree significant in controlling As transportation in Whitewood Creek. Based on GIS results, the location and evolution of contaminated floodplains along Whitewood Creek and the Belle Fourche River are very complex. The streams are different from each other and behave as their own systems. In Whitewood Creek, locations with high tailings area and removal are controlled by a possible range of factors such as knickzone geomorphology, bedrock lithology, and changes in stream energy due to topography. In the Belle Fourche River, reaches with high tailings area and removal are found about 7 km from the Whitewood Creek confluence and a 30 km stretch where rapid floodplain reworking occurs due to neotectonics from Precambrian basement adjustments. Tailings removed area and contaminated floodplain width graphs show that the Belle Fourche River has larger storage for tailings and undergoes more floodplain reworking due to higher flood frequency and neotectonics. In contrast, Whitewood Creek has lower storage and erosion due to decreasing mine sediment load at least since 1948 and channel incision into shale bedrock in some reaches. While the reworking of tailings into the stream is lower in Whitewood Creek than the Belle Fourche River, the tailings will remain on the floodplains for many generations.Item Open Access Composition and fabric of the Kupferschiefer, Sangerhausen Basin, Germany and a comparison to the Kupferschiefer in the Lubin Mining District, Poland(Colorado State University. Libraries, 2013) Lyons, Brianna E., author; Sutton, Sally, advisor; Ridley, John, committee member; Sale, Thomas, committee memberThe Kupferschiefer, or "copper shale," is a thin carbonaceous marly shale deposited during the Late Permian within the Zechstein Basin of central Europe. A classic example of a sediment hosted stratiform copper deposit, the Kupferschiefer is mineralized with Cu and other metals of economic interest such as Pb, Zn, and Ag. The unit is overlain by the Zechstein Limestone and underlain by the Weissliegend sandstone; it is most well known in Germany and Poland. Overall, the Kupferschiefer in the Sangerhausen Basin in Germany has been less studied than its counterpart in the Lubin mining district in Poland. Some previous studies compare the Kupferschiefer from the Lubin mining district, and more rarely the Sangerhausen Basin, to other stratiform copper deposits, but few compare data from both locations. This study analyzes, compares, and contrasts geochemical, mineralogical, and petrologic data from five Sangerhausen Basin locations and four locations in the Lubin and Rudna mines of the Lubin mining district. A total of 101 samples were examined: 61 Sangerhausen samples (41 from above the Kupferschiefer-Weissliegend contact, and 20 from below the contact) and 41 Lubin mining district samples (28 from above the Kupferschiefer-Weissliegend contact, and 13 from below the contact). Of these, 62 (36 Sangerhausen and 26 Lubin mining district) were geochemically analyzed, and 65 samples were observed in thin section (35 Sangerhausen, 30 Lubin mining district). The Sangerhausen Basin Kupferschiefer exhibits textural, geochemical, and mineralization characteristics broadly similar to those of the Lubin mining district Kupferschiefer, with a few distinct differences. Sulfide mineralization, in the form of disseminated spherules, blebs, aggregates, framboids, and bedding-parallel and -perpendicular veins, is observed in both locations on macro- and microscopic scales. The most abundant sulfide in mineralized samples from both locations is chalcocite, followed by chalcopyrite. Sulfide mineralization is commonly associated with the presence of quartz and carbonate veins in Lubin mining district samples, while mineralization is rarely associated with these veins in Sangerhausen Basin samples. Fluorescence from hydrocarbons is observed in association with sulfide mineralization in some samples, and is generally more common in samples from the Sangerhausen Basin than in those from the Lubin mining district. Both locations show similar geochemical trends with stratigraphic depth, as the units transition from Weissliegend to Kupferschiefer to Zechstein Limestone. The Sangerhausen Basin Kupferschiefer exhibits P2O5 enrichment (averaging 0.26 wt.%) compared to Lubin mining district Kupferschiefer and average shale P2O5 values (averaging 0.13 wt.% and 0.16 wt.%, respectively). Copper concentrations are greater in samples from the Lubin mining district (~14 wt.% max, most samples above ~1 to 2 wt.%) compared to Sangerhausen samples (~10 wt.% max, most samples below 0.5 wt.%). The lower ~25 cm of the Kupferschiefer is enriched in ore metals (Cu, Ag, Pb, Zn, and U) in both locations, and in the Sangerhausen Basin, in middle rare earth elements (REEs) as well. This suggests that the reactions resulting from interaction between fluids migrating from the underlying Weissliegend and overlying Zechstein evaporates mostly occurred in the lower 20 cm of the Kupferschiefer. Assuming that the REEs were carried in the mineralizing fluids, the differences in REE patterns from Sangerhausen samples taken 7 and 8 cm above the basal contact of the Kupferschiefer suggest that even within a single basin the reactions resulting from fluid interaction did not occur at the same stratigraphic level at all locations. The strata-form nature of the deposit suggests large scale bedding-parallel fluid flow. On a smaller scale, the orientation of sulfide, quartz, and carbonate veins and of elongated sulfide macro-blebs suggests that the local, small-scale flow direction is preferentially bedding-parallel as well, especially in the lower 20 to 30 cm of the Kupferschiefer where the matrix is primarily composed of alternating lenses of carbon- and clay-rich pods, and carbonate-rich pods. However, the presence of bedding-perpendicular sulfide blebs and carbonate and quartz veins illustrate that flow was not exclusively bedding-parallel. The Lubin mining district probably experienced at least two pulses of fluid flow, as illustrated by the presence of veins that exhibit alternating carbonate and sulfide precipitation; similar characteristics were not observed in the Sangerhausen Basin samples. The presence of both yellow and blue fluorescence of bitumen in Sangerhausen samples, however, suggests that there were at least two pulses of hydrocarbon migration. The generally well-sorted Lubin mining district Weissliegend was more permeable than the poorly-sorted Sangerhausen Basin Weissliegend.Item Open Access Diagenesis and geochemistry of the Lower Permian Ingleside Formation, Owl Canyon area, Larimer County, Colorado(Colorado State University. Libraries, 2018) Issa, Ahmad, author; Sutton, Sally, advisor; Ridley, John, committee member; De Long, Susan, committee memberThe purpose of this study is to determine the diagenetic history and timing of hydrocarbon migration in the Lower Permian Ingleside Formation as revealed in the Ingleside roadcut at Owl Canyon area, Colorado. The studied exposure is divided into fourteen beds composed of quartz arenite sandstone, limestone, dolomite, or siltstone. Observations from outcrop and thin sections, including calcite veins, carbonate-hosted vugs, and carbonate cement, suggest carbonate mobility throughout the outcrop. Stylolites parallel to bedding may have formed by pressure solution related to compaction, and pressure solution of carbonates is one possible source of carbonate that could have precipitated in veins or as cement. The formation was affected by other diagenetic processes, in addition to compaction and carbonate cementation, including feldspar dissolution and alteration and several stages of cementation. Cements include hematite, calcite, dolomite, kaolinite, and quartz overgrowth cement. Hematite cement was determined to have precipitated very early. Poikilotopic carbonate cement was precipitated very early, but after the precipitation of the hematite cement. Blocky calcite and blocky dolomite cements, the most common cements within the formation, were precipitated after the hematite and poikilotopic cements. Kaolinite cement was probably precipitated in association with feldspar dissolution and alteration, or occurred with feldspar dissolution during modern weathering. Hydrocarbon migration probably occurred before the precipitation of the blocky carbonate cement. The relationship between S and MgO in some sandstone samples may indicate that Mg and S have been added by diagenetic fluids. Also, K2O correlates with Al2O3 probably because both elements are mainly in the same phases, clay minerals, micas, K-feldspar, or glauconite. This study of the Ingleside outcrop provides some information about the diagenesis, possible timing of possible hydrocarbon migration through the Ingleside Formation, and geochemical and mineralogical composition of the exposure, which was used to interpret the diagenetic history throughout the outcrop. Therefore, this study adds to understanding of hydrocarbon migration and the hydrocarbon pathways in this part of the Denver Basin.Item Open Access Geochemical modeling-based prediction of water-rock interaction during aquifer storage and recovery utilizing selected Colorado Front Range aquifers(Colorado State University. Libraries, 2023) Doherty, Amanda, author; Sutton, Sally, advisor; Sale, Thomas, committee member; Ronayne, Michael, committee memberThis study characterizes the Fountain Formation, Ingleside Formation, and sandstones of the Dakota Group and considers the potential of these three formations as hypothetical Aquifer Storage and Recovery (ASR) targets. Compositional data from surface rock samples, including major, minor and trace elements from bulk rock geochemical analysis and mineral identification from petrography are used to infer a generalized mineral suite to represent each of the formations of interest. Similarly, compositional analyses from domestic water well samples, including major anions and cations and selected metals, were used as generalized representations of native water from each formation of interest. Finally, compositional data from treated city water was obtained and used as a generalized representation of injection water. The generalized rock data along with the generalized native water data represent a hypothetical injection environment while the treated water composition represents a hypothetical injection water. All water and rock data were used to populate a Single Pass Mixing equilibria Model that simulated an ASR system using the USGS geochemical modeling computer program PHREEQC (PH REdox EQuilibrium). Model results include mixed solution compositions, mineral saturation indices and estimates of mineral mass precipitation during simulated injection. Results of modeling suggest there is limited geochemical water-rock interaction during ASR in the hypothetical environment in this study. Model results indicate that the mixed solution composition is controlled more by the injected solution than by reactions occurring between the injection fluid and aquifer host material. Specifically, as greater volumes of hypothetical injection water are introduced with each model step, the compositions of the resulting mixed solutions increasingly resemble those of the injected water. The model predicted the precipitation of hematite, kaolinite and quartz during injection of the hypothetical injection water. Because aluminum was below detection in the water analyses and an arbitrary value less than the detection limit was used in the model, the prediction of kaolinite precipitation is not meaningful. Further, the model was constrained to not permit mineral dissolution, limiting the applicability of the model only to the consideration of mineral precipitation. In addition, benchtop leaching experiments were performed on rock samples to provide additional information about potential water-rock interaction. Benchtop experiment results are presented, but the focus of the study is primarily on geochemical modeling results. Water analysis results presented here suggest that the formations of interest currently contain good quality water. Modeling results suggest that injection of treated water would likely not lead to volumetrically important precipitation of minerals in the formations.Item Open Access Geological control on aquifer storage and recovery (ASR) feasibility and efficiency in carbonate aquifers (Edwards aquifer and Floridan aquifer)(Colorado State University. Libraries, 2024) Simbo, Christophe Wakamya, author; Sutton, Sally, advisor; Sale, Tom, committee member; Ronayne, Michael, committee member; Ridley, John, committee memberAquifer storage and recovery (ASR) is increasingly being used to enhance freshwater security and sustainability. Though proven technology, ASR implementation and efficiency are mainly controlled by the aquifer system's geological characteristics. Aquifer or reservoir quality, aquifer geochemistry and heterogeneity, and ASR-induced stress exerted on aquifer systems affect the operation of ASR and, hence, ASR recovery feasibility and efficiency. This dissertation evaluates the feasibility of ASR operations in two major carbonate aquifers in the USA: the brackish portion of the Edwards aquifer and the Floridan aquifer. Aquifer matrix petrology and geochemistry, groundwater geochemistry, surface water geochemistry, and time series water chemistry coupled with numerical modeling with PHAST and Geochemists' Workbench (GWB), and analytical modeling were used to understand the aquifers and evaluate ASR optimization strategies. The Edwards Aquifer petrography provides insights into the aquifer texture, fabric, and aquifer/reservoir quality controlled by depositional and post-depositional processes. Though the development of porosity and permeability are likely controlled by the precursor texture of the aquifer matrix, diagenetic processes, mainly dolomitization together with fracturing and dissolution, may be the main agents affecting aquifer quality for ASR operation. Suitable aquifer zones for water storage are characterized by permeability likely controlled by intercrystalline, fracture, and vuggy porosity in dolomitic zones. Bulk aquifer geochemistry documents major and trace elements, with high MgO/CaO revealing extensive dolomitization preferentially located towards the middle of the Person and Kainer Formations, aquifer units within the Edwards aquifer system. The relatively higher content of SiO2, Al2O3, and, to some extent, K2O and TiO2 in confining layers points to a modest increase in clay minerals compared to aquifer sections. Clay minerals, together with compaction features observed in confining layer thin sections, potentially reduce confining layer permeability and porosity. However, high fracture porosity within the Regional Dense Member (RDM) confining layer separating both Edwards aquifer zones offers potential pathways connecting both zones. That these fractures may, in fact, be pathways is supported by changes in groundwater hydrochemistry in the non-targeted aquifer zone (Kainer) during the initial ASR recharge cycle. Based on injectant and groundwater chemistry and time series water chemistry of recovered water samples during the first ASR operation cycle, initial and evolved hydrochemical facies were evaluated in the Edwards aquifer ASR operation (in New Braunfels). Forward GWB water-water and water-rock interaction modeling revealed the mixing of the injectant and the native groundwater to be the main contributing factor in the hydrochemical facies evolution of groundwater during the first ASR recharge cycle. Estimated hydraulic conductivity values using the numerical PHAST model and corroborated by the Hemker analytical model support the combined effect of lateral flow and vertically-induced flow of high total dissolved solids (TDS) groundwater from the Kainer Formation into the Person Formation via the RDM confining layer during ASR recovery. Estimated hydraulic property values (hydraulic conductivity and porosity) of these three aquifer layers aided in predicting the recovery rate to optimize ASR operations. Implementation of two ASR wells, respectively screened in the Person and Kainer Formations, presents a potential long-term ASR optimization strategy at the Edwards aquifer study site. Induced arsenic releases to concentrations higher than their maximum contaminant level (MCL) of 10 μg/L hinder aquifer storage and recovery (ASR) operations worldwide. Statistical data and time series analyses of the recovered water hydrochemical data were used to assess the operational methodology maintaining the buffer zone for arsenic attenuation during ASR operations in the Floridan aquifer. Additionally, based on Injectant and groundwater hydrochemical data with geochemical data of the aquifer matrix , 1D GWB reactive transport model was used to assess the buffer zone operation methodology that holds promise in managing arsenic releases during ASR operations in the Floridan aquifer. Time series data from the Tampa ASR operations show a positive correlation between percent recovery and arsenic concentration in the recovered water, with high recovery percentages inducing mobilization of arsenic up to 38 μg/L, a value roughly four times the arsenic maximum contaminant level of 10 μg/L. Further, the developed 1D forward reactive transport model suggests underlying processes that control arsenic behavior upon injection of oxygenated source water into a reducing carbonate storage zone. Two model scenarios were used in this study. Model scenario 2 developed such that a larger oxygen front expanded up to 565 m away from the ASR well, three times further than in scenario 1, and promoted the production of Fe(III) oxides/oxyhydroxides with abundances up to 18,700 µg/Kg formed at 555 m away from the ASR well. These Fe(III) oxides/oxyhydroxides may provide sorbing sites that attenuate arsenic concentrations in the groundwater.Item Open Access Hydrogeologic characterization of the Fountain Formation: prospective aquifer storage and recovery targets in Front Range Colorado(Colorado State University. Libraries, 2018) Collazo, Daniel, author; Sutton, Sally, advisor; Sale, Thomas, committee member; Ronayne, Michael, committee memberAquifer storage and recovery (ASR) is a method of water storage that typically involves using the same well to inject water into and recover water from an aquifer. Benefits of ASR include lower capital costs than surface storage methods, negligible losses due to evaporation or potential contamination, and a much smaller land use footprint. This method of storing water is of interest for northern Colorado because of the location of existing water supply infrastructure and bedrock aquifers along the Front Range and the need for additional water storage. A potential storage zone for ASR in northern Colorado is the Fountain Formation. The Fountain is a Pennsylvanian-Permian arkosic conglomeratic sandstone with interbedded siltstone and shale that outcrops in a narrow, north-south trending belt from southern Wyoming to central Colorado. Within the outcrop belt, the Fountain is about 500 to 4500 feet thick and dips steeply to the east. The Fountain Formation was formed from sediments shed off the Ancestral Rocky Mountains, an uplift associated with the Ouachita-Marathon Orogeny, and deposited mainly in alluvial fans and braided streams. The composition of the formation is heterogeneous with permeable facies such as coarse sandstones adjacent to impermeable facies such as mudstones. This study characterizes the hydrogeology of the Fountain Formation to assess the feasibility of the Fountain as a storage zone for ASR, and in particular in northern Colorado. Data from 1262 wells in the Fountain were collected from the Colorado Division of Water Resources AquaMap database to characterize the hydraulic properties of the formation. The data were used to calculate specific capacity for each well and plotted on maps to help identify areas of interest for ASR. Within the formation there are wells with high yields and specific capacities which suggests that the Fountain can host high yield wells suitable for ASR. Water level elevation maps were also made for selected quadrangles and provide an approximation of the water level surface within the aquifer as well as the direction of water flow. Well-cemented outcrop samples were collected and tested for permeability using an air permeameter. The samples all have relatively low permeabilities, but it is likely that the less cemented lithologies have much higher permeabilities. The heterogenous lithology of the formation is likely able to store large volumes of water while preventing the water from migrating away from an ASR well. The results of this study suggest that the Fountain Formation is a feasible target for ASR implementation.Item Open Access Hydrologic characterization of upper Permian-Cenozoic sedimentary strata of Larimer County: prospective aquifer storage and recovery targets(Colorado State University. Libraries, 2017) Adam, Adam, author; Sutton, Sally, advisor; Sanford, William, committee member; Sale, Thomas, committee memberProviding adequate water storage is an on-going problem along the northern Colorado Front Range. This study compiles existing hydrogeological data from water wells to identify potential ASR sites in eastern Larimer County, Colorado. These water well data are used to evaluate both geographic localities and individual lithologic units. All stratigraphic units younger than the Pennsylvanian-Permian Fountain Formation and reported to host water wells in eastern Larimer County are considered here. A total of 1094 AquaMap water well reports have been mined for data, including depth, pumping level, static water level, lithology, location, date drilled, and yield. Additionally, specific capacity has been calculated for each well. The data points were plotted using ArcGIS and geological maps from US Geological Survey as base maps. The main parameters considered are water well yields and specific capacities. Yield is an indication of the ability of an aquifer to permit movement of water, but the yield data available may not reflect the maximum ability of a well to produce or store water. This is because water is pumped out according to the usage or purpose of the well, with irrigation and livestock wells typically yielding more than household wells. In some locations the aquifers considered can likely produce more than indicated by reported yields. Based on both hydrogeological properties and widespread occurrence in the study area the Pierre Shale Formation, the Lytle Formation, and the Ingleside Formation appear to show the greatest promise as ASR targets. Additional units that could be worth further consideration include the Jelm and Lykins Formations. Based solely on hydrogeological data, the White River, Laramie, and Fox Hills Formations would be the strongest candidates for ASR, but are geographically limited to the far northeast corner of the county. In addition, well data from unconsolidated alluvial deposits suggest strong potential for ASR, especially near the eastern edge of the County, but the combination of very high permeability and surface exposure would make ASR in these deposits challenging because of difficulty maintaining control of stored water. Based on well data, there are some specific localities that may merit further consideration for ASR, including the vicinity of Laporte, where several stratigraphic units host wells with high yields and high specific capacities. Similarly, there are wells in several stratigraphic units, including the Pierre Shale Formation, CarlileGraneros-Mowry Shales, Owl Canyon Formation, Lyons Formation, and Lytle Formation, in an area to the west of Loveland that show promise for ASR. Additionally, the Pierre Shale Formation hosts several clusters of wells indicating strong potential for ASR; the best developed of these clusters are in the northern third of the Larimer County, specifically northwest of Wellington.Item Open Access Organic geochemistry of Mesoproterozoic Nonesuch Formation at White Pine, Michigan, USA(Colorado State University. Libraries, 2012) Fourgani, Aiyda Ibrahim, author; Sutton, Sally, advisor; Ridley, John, advisor; Cavdar, Gamze, committee memberThe quality and quantity of the preserved organic matter (OM) in the Mesoproterozoic Nonesuch Formation at White Pine are evaluated in this project. Specifically, I have considered whether the rocks had source rock potential and whether there is a relationship between the OM and copper mineralization. The copper mineralization and hydrocarbons migration pathways are hypothesized to be related. There are three possibilities for the relationship. The copper ore fluid may have migrated with the hydrocarbons. The copper may also have precipitated where the hydrocarbons had accumulated, or the copper precipitated where there were accumulations of OM. Three cores (42C, 37F, and 30G) from in or near the White Pine mine were described and analyzed. The sampled core intervals are mostly from the Lower Nonesuch Formation with some from higher intervals. The overall lithology is gray laminated siltstone, with some sandy siltstone and lesser shale and sandstone. The core samples have various colors, with brown to dark brown samples hosting organic matter. The most abundant minerals are quartz, feldspar (plagioclase, orthoclase), mica, and some rock fragments; calcite and chlorite are mostly found as cement. Various analyses were done to investigate the organic matter. For estimating the maturity, kerogen type, and potential source rock quality, samples were subjected by the Rock Eval pyrolysis. Also other techniques were used for evaluating maturation, including ultraviolet microscopy and vitrinite reflectance microscopy; it was determined that the majority of samples have little to no vitrinite-like material. The organic matter as analyzed by the UV microscope is observed to be of three types, kerogen, bitumen, and oil inclusions. The oil inclusions are mostly found in the sandy siltstone samples. The organic matter is mostly not fluorescent possibly because it is overmature or immature; it contains less than about 10% pyrolyzable hydrocarbons. The organic matter may have been produced from remains of organisms like algae and fungus deposited within a lacustrine and/or transitional marine environment. The generative potential of the organic matter is in the poor to fair range. The range of TOC (total organic carbon) content is between 0.01 and 0.86 wt %. The highest value is detected above the mineralization zone in the Upper Nonesuch Formation. The kerogens of the Nonesuch Formation are types III and IV, types that usually are gas prone, or have no hydrocarbon potential. The samples may have been oxidized by copper bearing fluids which altered the organic matter and reduced its potential to produce hydrocarbons. Overall, the organic matter of the lower Nonesuch Formation at White Pine has no potential to produce hydrocarbons.Item Open Access Paleo-fluid migration and diagenesis in the Pennsylvanian-Permian Fountain Formation(Colorado State University. Libraries, 2013) Hogan, Ian, author; Sutton, Sally, advisor; Ridley, John, committee member; Sale, Thomas, committee memberThe Pennsylvanian-Permian Fountain Formation is an arkosic conglomeratic sandstone that was deposited in fluvial environments along the eastern flanks of the ancestral Rocky Mountains. The formation owes its pinkish red color to hematite cement that was precipitated early in its diagenetic history. Within the formation are whitened strata that crosscut laminations and facies boundaries, indicating that they are the result of a post depositional process. Whitened features are seen in core, indicating that they are not caused by modern weathering processes. Whitened strata similar to those present in the Fountain Formation are usually the result of the migration of reducing fluids. These fluids reduce and remove hematite cement leaving the fluid migration pathways whitened. Fluids that can cause large-scale reduction and removal of iron oxides include basinal aqueous brines and hydrocarbons. Whitening within the Fountain Formation appears in a predictable stratigraphically-controlled manner and is most common in coarse channel sandstone facies that are adjacent to laterally continuous paleosol mudstones. The predictable distribution of whitened strata in outcrop suggests that fluid followed preferential pathways. Outcrop analysis indicates that these pathways are closely associated with thin paleosol mudstones and overbank deposits that seem to have focused the paleo-fluids that then flowed laterally along them in the coarser channel sandstones. Laterally continuous paleosol mudstones therefore may have played an important role in determining the spatial location of paleo-fluid migration pathways. Fluids moved through the formation as stringers that took up less than 15% of the total rock volume. The Fountain Formation has a complex diagenetic history and has undergone multiple stages of cementation. A late stage dolomite cement contains organic matter, hydrocarbon inclusions, and is associated with bitumen. This cement is restricted to whitened strata and likely precipitated from a hydrocarbon-bearing fluid. The hydrocarbon-bearing fluid may have been the fluid that was responsible for whitening sections of the Fountain. Fluid inclusion data indicate that the precipitation of this cement took place after the formation was buried to a depth of at least 1.3km, which would have been during or after Laramide deformation. The presence of bitumen and hydrocarbon inclusions in strata that were not buried to hydrocarbon generating depths indicates that the hydrocarbon-bearing fluid likely migrated through the formation from deeper in the basin. The amount of whitening in outcrop decreases in the northern study sites and may be related to a decrease in coarse channel sandstone facies. The lesser abundance of those facies at northern study sites may be because those sites were further from the sources for coarse material and were associated with lower energy environments. Although there is less whitened rock at the northern sites, the amount of fluid that passed through them may have been similar to the amount of fluid that passed through the southern sites. Evidence of this is a higher amount of feldspar alteration in whitened strata in the northern site, which may have been caused by more fluid flow per volume of rock because there were fewer coarse channel facies to act as conduits.Item Open Access Soil weathering under mountain pine beetle killed trees, Grand County, Colorado(Colorado State University. Libraries, 2013) Denison, Christopher W., author; Sutton, Sally, advisor; Ridley, John, committee member; Stednick, John, committee memberThe objective of this study is to assess differences in soil weathering processes under mountain pine beetle killed trees, as compared to soil weathering under living trees. As pine beetle (Dendroctonus pondersoae) infected trees die, pine needles are shed and accumulate on the forest floor, which may lead to changes in soil pH and soil temperature as the organic horizon thickens and insulates the soils below. Additionally, decomposition of the dropped needles may cause chemical changes in the substrate. These changes in soil pH, temperature, and chemistry are likely to affect weathering of soil minerals. Two hypotheses related to soil weathering processes under beetle infected trees are evaluated: (1) the death of pine trees and accompanying increased pine needle decomposition has increased chemical weathering of the substrate, and (2) an increase in soil weathering under dead pine stands has increased downslope physical migration of weathered material. This study was conducted in the Kauffman Creek watershed in the mountain pine beetle infected Arapahoe National Forest of Grand County, Colorado. Soil samples were collected from a south facing hillslope and from elevations of approximately 9100 to 9400 feet, thus minimizing differences in weathering processes related to hillslope aspect or elevation. Kauffman Creek incises mountainous terrain and the study area is hosted by Paleocene - Eocene sedimentary rocks of the Coalmont Formation. Soils of Kauffman Creek are predominately inceptisols and entisols. The field site was chosen to show a range in pine beetle infestation and health conditions of pine trees on the hillside. On the hillslope there are stands of healthy (green) or recently attacked (brown) pine trees and there are other areas where the pines are in the final stages (gray) of beetle infestation (4+ years post attack) and have dropped most of their needles. A study of soil characteristics (i.e. grain size, inorganic geochemistry, mineralogy, pH, and saturated paste electric conductivity) was conducted to evaluate soil weathering processes. Analytical results indicate that the mean grain size is approximately 1.3 times coarser beneath the gray stands than beneath the healthy-appearing, green pine stands. Major element geochemistry shows average concentrations of Na and K are greater, and average concentrations of Mn and Mg are smaller, in soils beneath the gray pine stands than from those under green stands. The differences in soil chemistry within the soils beneath the gray stands, compared to the soils beneath the green pine stands, suggest increased chemical weathering of soil under the gray stands. Chemical results for soils under the brown stands suggest they also have experienced increased weathering, compared to the green stands. Petrographic results show that the modal percentage of quartz is approximately 1.2 to 1.4 times greater in the soils beneath the gray stands than in the soils under the green stands, while the modal percentages of soil aggregates and micas decrease from the soils under the green stands to the soils under gray trees. The average topsoil pH is lower in the soils beneath the brown and gray trees than in the soils beneath the healthy pines. Soil conductivity data suggests an increase in soil moisture under the brown and gray pine stands. Overall, increased pine needle litter and its decomposition appear to have increased soil weathering. Downslope migration of weathered material was not evident in the results of this study.