Browsing by Author "Ridley, John, committee member"
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Item Open Access A test of general shear versus folding for the origin of a cryptic structural feature, Nason terrane, Washington(Colorado State University. Libraries, 2013) Jackl, Max Alexander, author; Magloughlin, Jerry, advisor; Ridley, John, committee member; Baird, Graham, committee member; Stednick, John, committee memberThe Nason terrane of the Cascades Crystalline Core is a complex tectonostratigraphic terrane that has been the topic of much study due to its long deformational history and importance in the debate surrounding the Baja B.C. hypothesis. Structural patterns along Nason Ridge in the central part of the terrane have been interpreted as the result of either the presence of a major shear zone or the development of fold interference patterns. Distinguishing fold-controlled lineations from shear zone produced lineations can be a complex, but important problem. This study aims to provide a better understanding of high-temperature deformation which may be obscured due to extensive recrystallization. Outside of the cryptic zone the foliation is steeply dipping and striking to the NW with lineations which are subhorizontal. Previous observations revealed a structural zone ~1 km wide striking NW-SE. Within the zone, fold hinges and mineral lineations are typically subvertical with mineral lineations clustering tightly and trending NE, indicating that this zone has a fundamentally different structural fabric than the surrounding terrane. Fold hinge lines are more dispersed along the trend of the zone, possibly reflecting incomplete rotation of pre-existing fold hinges into a near vertical orientation. Anisotropy of magnetic susceptibility analysis indicates the magnetic fabric correlates well with lineations and foliations measured in the field, and lineations likewise shallow to near horizontal outside the zone. Quantification of the strength of the AMS fabric reveals an oblate spheroid, which is interpreted as a proxy for an oblate strain ellipsoid, indicating the presence of a component of pure shear. Asymmetrical microstructural features present include tailed porphyroclasts, mineral fish, and domino clasts. Sense of shear indicators agree with the hypothesized NE-side-up motion (Magloughlin, 1990). Electron backscatter diffraction analysis reveals biotite and amphibole possess a lattice preferred orientation (LPO), whereas quartz and plagioclase have a nearly random crystallographic fabric. The biotite and amphibole LPO was used to determine NE-side-up sense of shear in thin sections from the cryptic zone. It is clear from the agreement between outcrop scale structures, magnetic fabric, microstructures, and crystallographic fabric that a significantly different structural fabric is tightly localized on the zone. The highly focused nature of the zone and the lack of structures typically created by fold interference indicates that superposed folding is unlikely. These data, coupled with geothermobarometric constraints, point to a zone of displacement best characterized by northeast-side-up general shear.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 Depositional environment and facies architecture of the Lower to Middle Ordovician carbonate ramp succession, Öland, southern Sweden(Colorado State University. Libraries, 2014) Cigri, Ali Riza, author; Egenhoff, Sven, advisor; Ridley, John, committee member; Çavdar, Gamze, committee memberThe Lower to Middle Ordovician carbonates of Öland, southern Sweden, exhibit outcrops of up to 12 m thickness and rest conformably on Cambrian black shales of the Alum Formation. Based on lithological and sedimentological characteristics, nine carbonate facies were identified within the successions that are grouped into four facies associations (FAs). FA 1 is composed of glauconite- bearing mud- to wackestone facies. FA 2 consists of three glauconite- and one glauconite- and Fe-ooid bearing mud- to packestone carbonate facies. Deposits of FA 3 are carbonate mud- to wackestone facies. FA 4 is characterized by one Fe- ooid bearing and four other mud- to packstone carbonate facies. The studied carbonate succession is subdivided into three stratigraphic units referred to as Intervals 1 to 3. Interval 1 consists of the Köpingsklint and Bruddesta Formations located at the base of the succession. Interval 2 is composed of the Horns Udde formation in the middle level of the succession, and Interval 3 is characterized by the Gillberga Formation situated at the top of the succession. FA 1 rocks were deposited in an offshore proximal setting, whereas FA 2 records an offshore distal setting during "starved" times. FA 3 and FA 4 rocks were deposited during the "normal" times reflecting offshore proximal and distal settings, respectively. Heterozoan assemblages, allochthonous Fe- ooids, and abundance of carbonate mud within the facies suggest that the studied carbonate succession experienced temperate to sub-tropical sea-water conditions during deposition despite its paleo-latitudes equivalence to what would be temperate to cool-water environments of modern examples. Three 3rd order sequences having regressive systems tracts (RSTs) and transgressive systems tracts (TSTs) bounded by maximum regressive surfaces (MRSs) were determined within the studied succession based on the transgressive versus regressive sequence stratigraphic model. The MRSs are situated at the top of the RSTs reflecting maximum sea-level drops. Interval 1 is interpreted to represent both TST and RST characterized by glauconite-bearing facies, and have a sequence boundary (MRS) at the base. Interval 2 contains two sequence boundaries (MRSs) and is comprised of two TST and one RST characterized by carbonate facies. Interval 3 has a sequence boundary (MRS) at the top and is composed of one RST discriminated by glauconite-bearing facies. The Lower to Middle Ordovician carbonates and their subsurface equivalence have high potential in terms of conventional and unconventional petroleum exploration based on their lithologic character and positions in the Paleozoic petroleum system in the Baltic Sea of Scandinavia and adjacent areas.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 Faulting in the Foam Creek Stock, North Cascade Mountains, Washington(Colorado State University. Libraries, 2017) Kahn, Adrian Walter, author; Magloughlin, Jerry, advisor; Ridley, John, committee member; van de Lindt, John, committee memberThe Foam Creek Stock (FCS) is a tonalite pluton in the northwestern part of the Nason Terrane in Washington state, a region that has experienced a wide range of structural regimes. Faults cutting the FCS have been studied through field, microscope, fluid inclusion, and geochemical methods. The purpose of this study is to understand the nature of these faults, and their place in the regional tectonic history. The FCS is cut by two populations (P1 and P2) of small-scale faults that share similar orientations but are microstructurally and geochemically distinct. P1 faults are generally E-dipping and host a distinct, bleached alteration halo and a thin, highly altered fault core containing the secondary minerals adularia (K-feldspar), chlorite, albite, and actinolite, and remnant host minerals quartz and altered plagioclase. P1 fault cores are thin (<1 mm) and display small apparent offsets (<2 cm). P2 faults cut P1 faults, dip N, S, and E, have generally steeper dips and greater displacements (average 14.1 cm apparent offsets) than P1 faults, and host predominantly secondary adularia and fractured host rock within thicker (~3 cm), more well-developed cataclastic fault cores. P1 faults show microstructural evidence of grain boundary bulging in quartz, along with seams that are interpreted to have hosted diffusive mass transfer (DMT) within the cataclastic fault core, suggesting a component of aseismic deformation accommodated some of the strain. In contrast, P2 fault cores range from random fabric to weakly foliated cataclasite, and host aseismic DMT and coseismic pseudotachylyte, indicating strain was accommodated across a wide range of strain rates. Kinematic analysis using both outcrop and microscale observations indicates that P1 faults are reverse, whereas P2 faults are normal and sinistral. Chemical analyses of the fault cores of the two populations, using a portable XRF reveal geochemical changes accompanying faulting. The most significant changes include P1 faults are enriched in Pb (~100%), and depleted in Ti (~50%), Ca, Sr, and Zn, whereas P2 faults are enriched in K (~40%) and Rb, and depleted in Fe (~30%), Mn, Ca, Sr and Zn. Interpretation of textural relationships between primary and secondary minerals suggests the fluids that migrated through both fault populations may have been initially sodic, and a shift in composition produced a sequence of alteration reactions with the host FCS tonalite. The final product of this changing fluid-rock system was adularia precipitation within fault cores, which in turn served to strengthen the faults. Mechanical strengthening likely inhibited reshear of faults, and thus additional strain of the pluton was accommodated along newly nucleated fault planes through slip delocalization. Fluid inclusion microthermometry, combined with observed deformation mechanisms and secondary mineral assemblages, allowed for estimation of temperature of trapping of the fluids, and revealed temperature conditions of ~289 ± 24°C during P1 faulting, and ~262 ± 23°C during P2 faulting. When combined with T-t curves constructed using K-Ar and Ar-Ar data from previous studies, the estimated age of the faults is ~71.9 ± 3.5 Ma for P1 and 69.2 ± 3.5 Ma for P2. Using these ages, it is proposed that Late Cretaceous deformation of the FCS observed in this study records relative counterclockwise rotation of the converging Farallon Plate. The resultant shift from E-W compression to dextral transpression was locally expressed as reverse P1 faults followed by N-S P2 extension with a sinistral component during regional post-metamorphic uplift and dextral shear.Item Open Access Fluoroalkyl and fluoroaryl fullerenes, polycyclic aromatic hydrocarbons, and copper(I) complexes: synthesis, structure, electrochemical, photophysical, and device properties(Colorado State University. Libraries, 2020) Reeves, Brian J., author; Strauss, Steven H., advisor; Shores, Matthew P., committee member; Rappé, Anthony K., committee member; McNally, Andrew, committee member; Ridley, John, committee memberIn many fields of research, ranging from materials chemistry to medicinal chemistry, understanding the structural, electrochemical, and photophysical properties of materials is essential to establishing trends and predicting usefulness and future performance. This work has focused on the impact of strongly electron withdrawing perfluoroaryl and perfluoroalkyl substituents on the properties of fullerenes, polycyclic aromatic hydrocarbons (PAHs), hetero-PAHs, and copper(I) complexes with the goal of establishing and understanding the fundamental reasons for any observed trends. In Chapter 1, the first successful example of vacuum-deposited organic photovoltaic cells (OPVs) based on a fullerene derivative and a small-molecule donor is reported. A series of thermally robust fluorous fullerene acceptors with experimental gas-phase electron affinities ranging from 2.8 to 3.3 eV are paired with new dicyanovinyl thiophene-based molecular donors to enable direct comparison of their performance in planar and bulk heterojunction architectures in cells fabricated by vacuum deposition. Unprecedented insights into the role of the acceptor intrinsic molecular and electronic structures are obtained, which are not obscured by solvent and additive effects as in the typical solution-processed fullerene-based OPVs. Additionally, the fullerene derivative, C60CF2, was utilized in vacuum-deposited organic field effect transistors (OFETs), and it was shown to have superior device lifetime compared to C60 based OFETs. In Chapter 2, a new synthesis of 9,10-bis(perfluorobenzyl)anthracene, a promising blue organic light emitting diode (OLED) material is reported. The yield was improved from 7% to 17%, while the separations conditions were improved to only require one stage of HPLC. In Chapters 3 and 4, the trifluoromethylation of two hetero-PAHs, phenanthroline and phenanthridine, is discussed. The structure, solid-state packing, and electronic properties of the products are examined. Previously unknown structure-property relationships were established between the electronic properties and the position of CF3 groups. Additionally, the synthesis and excited-state dynamics for a series of homoleptic copper(I) phenanthroline complexes with 2, 3, and 4 trifluoromethyl groups are reported. Surprisingly, the observed time-resolved dynamics and emission trend is that addition of trifluoromethyl groups past two decreases the excited state lifetime and increases excited-state distortion.Item Open Access Geologic mapping and kinematic analysis of the Independence Mine shear zone in the Sangre de Cristo Range, southern Colorado: extensional reactivation of a Laramide reverse fault(Colorado State University. Libraries, 2023) Sitar, Michael C., author; Singleton, John, advisor; Ridley, John, committee member; Leisz, Stephen, committee member; Caine, Jonathan Saul, committee memberThe Sangre de Cristo Range in southern Colorado records some of the deepest Cenozoic structural levels in the Rocky Mountain region. Exposures of Laramide-age contractional mylonites show evidence for brittle-plastic extensional overprinting associated with the Rio Grande rift. This study examines the relation between Laramide contraction and Rio Grande rift extension by detailed geologic mapping and kinematic, geochronological, and geochemical analyses in a 50 km2 area centered on the Independence Mine shear zone (IMSZ), formerly called the Independence Mine thrust. The IMSZ is a 15- to 100-meter-thick, shallow-to-moderately (25°–62°), WSW-dipping brittle-plastic shear zone near the topographic base of the western flank of the range. It displays microstructural evidence for initiation as a top-NE contractional mylonite zone consistent with Laramide kinematics but is pervasively overprinted by deformation fabrics indicating top-SW extensional reactivation. Top-SW microstructures are characterized by phyllosilicate-lined C- and C'-shear bands and mixed brittle-plastic deformation of quartz. Mapping shows that the IMSZ is the thickest member of a system of mylonitic shear zones that dip shallowly to moderately (25°–67°) to the WSW and are hosted primarily within Proterozoic gneiss. Shear zones in amphibole-rich gneiss are commonly dominated by chlorite whereas those in quartzo-feldspathic gneiss have abundant white mica. Many of the thinner shear zones also record top-SW overprinting of top-NE fabrics. Though both top-NE and top-SW shear fabrics involve cataclasis and quartz dislocation creep, extensional overprinting appears to be mostly restricted to mylonites where secondary phyllosilicates form an interconnected weak phase. These relations are interpreted as fluid-mediated, reaction-weakening gradients where lithologically controlled rheological contrasts were variably sensitive to extensional reactivation. One top-SW shear zone adjacent to the IMSZ cuts a gabbro stock that was dated at 25.7 ± 0.7 Ma using LA-ICP-MS zircon U-Pb geochronometry. Synkinematic monazite grains in two samples of the IMSZ yield LA-ICP-MS U-Pb and U-Th-Pb ages of 24.9 ± 3.0 Ma and 22.2 ± 0.7Ma, respectively. These data are consistent with extensional reactivation occurring during Late Oligocene to Early Miocene time. The IMSZ and associated reactivated shear zones may represent mid-crustal extension that was widespread in the earliest stages of Rio Grande rifting before extension shifted to high-angle brittle-regime normal faults along the range front.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 Influence of geochemical processes on geotechnical stability of tailings storage facilities(Colorado State University. Libraries, 2023) Orcutt, Heath Marie, author; Scalia, Joseph, IV, advisor; Bareither, Christopher, advisor; Ridley, John, committee memberIncorporation of geochemically induced material changes and weathering patterns into geotechnical design and long-term stability analyses of tailings storage facilities has yet to be implemented widely or consistently. Tailings are deposited in disequilibrium with the surrounding environment and must undergo physical, chemical, and biological weathering to reach their most stable form. As a result, the geotechnical properties of the tailings (i.e., particle size, water retention capacity, shear strength, etc.) change over time. Herein, an in-depth review of published literature is provided, ranging across multiple disciplines (geochemistry, geotechnical engineering, hydrogeology, environmental engineering, mining engineering), and focusing on studies that document or allude to material property changes of weathered sulfidic base metal tailings. Synthesized visual aids are provided as a framework for beginning interdisciplinary conversation that couples geochemistry and geotechnical engineering. By drawing attention to potential geochemically induced failure modes, I hope to draw connections between geochemistry and geotechnical engineering that are fundamental to developing robust designs and advanced monitoring plans that ensure long-term tailings storage facility stability. A "proof of concept" laboratory design is presented which analyzes changes to the physical material properties (compressibility, permeability, and shear strength) of saturated fine-synthetic tailings mixed with calcite at different pH values. Overall, this report seeks to lay the foundation for future study and advance communication between experts.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 Petrogenetic analysis of the Wenatchee Ridge Orthogneiss in the North Cascade Mountains, Washington State(Colorado State University. Libraries, 2014) Zaggle, Richard Haster, author; Magloughlin, Jerry, advisor; Ridley, John, committee member; Strauss, Steven, committee memberPetrogenetic analysis of the Wenatchee Ridge Orthogneiss (WRO) in the Nason Terrane of the North Cascade Mountains has been undertaken in order to gain insight into epidote-bearing TTG plutonism associated with mid-Cretaceous orogenesis in the North American Cordillera. Discriminant analysis indicates the WRO is very similar to Archean TTGs based upon characteristic geochemical values (Yb <1, Sr/Y >150, La/Yb >15, Y<6) and thus may provide insight into Archean crustal generation processes. Samples were taken from within the pluton and from within the surrounding banded gneiss. The pluton is chemically heterogeneous and samples all show some degree of foliation which is concordant with the foliation in country rocks. Samples range from leucotrondhjemite to granodiorite and contain oligoclase, quartz, potassium feldspar, muscovite, biotite, and epidote. SiO2 is 56.3-76.8% and REE data show that the samples are highly depleted in HREEs, variably depleted in LREEs, and have an average Eu/Eu* of 1.36±0.5. Though positive Eu anomalies are typically associated with plagioclase accumulation, the WRO appears to lack any correlation between plagioclase and Eu/Eu*. Geochemical results and the tectonic setting of the WRO indicate the initial magma may have formed as a partial melt of overthickened eclogitic crust. The subsequent LREE depletion and high positive Eu anomalies in the most evolved samples may be controlled by amphibole, epidote, and/or titanite fractionation. LA-ICP-MS analyses will indicate whether these phases had significant control on the REE signature of the WRO. Deformation-driven differentiation would have controlled any fractionation of amphibole, epidote, and/or titanite in the WRO magma which has viscosities of ≥106.8 Pa•s at 1000°C. Differentiation likely occurred simultaneously with intrusion into a lower crustal zone of plastic strain, resulting in the WRO's heterogeneity, sheeted nature, and syn-tectonic fabric.Item Open Access Preparation, regioselective chemistry, and electronic properties of perfluoroalkylfullerenes(Colorado State University. Libraries, 2013) Whitaker, James B., author; Strauss, Steven H., advisor; Chen, Eugene, committee member; Finke, Rick, committee member; Williams, Bob, committee member; Ridley, John, committee memberA systematic study of how various reaction parameters affect the product distribution of gas-solid reactions was carried out in a new reactor of local design. These reactions involve the trifluoromethylation of C60, C70, and the endohedral metallofullerenes Sc3N@C80 and Y3N@C80; and in particular, the reactions were optimized to favor C60(CF3)2 and C60(CF3)4. A new solution phase homogeneous perfluoroalkylation method was used to prepare a series of 1,7-C60(RF)2 compounds with different RF chain lengths and branching patterns. A range of analytical methods including 19F NMR and UV-vis spectroscopy, APCI mass spectrometry, and X-ray crystallography were used to structurally characterize the compounds. Cyclic voltammetry, DFT E(LUMO) calculations, and gas phase electron affinity (EA) measurements were used to determine the substituent effect of the RF groups. The results conclusively showed that the solution phase E1/2, calculated E(LUMO), and EA values-- that are typically assumed to be correlated for a series of electron acceptors-- are not always correlated. Several highly efficient and selective methods were developed for the further functionalization of selected trifluoromethyl fullerenes (TMFs). These new functionalized TMFs were structurally characterized using the aforementioned analytical techniques and the X-ray crystal structures of five new derivatized TMFs were determined. Analysis of the how these newly derivatized TMFs pack in a crystalline solid revealed fullerene density values that were in general twice that of reported fullerenes that pack in the same motifs. These derivatized TMFs also exhibited extended networks of short C···C distances between fullerene cages of adjacent molecules that has been correlated to increased free charge carrier motilities in organic photovoltaic device active layers. The solution phase E1/2 values of the most commonly used fullerene derivatives in OPV devices were measured under carefully controlled conditions and revealed that poor reporting of electrochemical conditions, mistakes interpreting electrochemical data, and fullerene impurities have combined to cause significant confusion about the reported electrochemical values in the literature. A preliminary study of 32 OPV devices fabricated with active layers containing perfluoroalkylfullerenes (PFAFs) indicated that (i) PFAFs can function as suitable electron acceptors in OPVs, and (ii) that a more detailed study examining the complex electronic interplay between the fullerene electron acceptor and polymer donor is warranted.Item Open Access Shear strength of coal combustion product by vane shear(Colorado State University. Libraries, 2018) Herweynen, Wesley J., author; Bareither, Christopher A., advisor; Scalia, Joseph, advisor; Ridley, John, committee memberThe objective of this study was to evaluate the shear strength of a coal combustion product (CCP) using the vane shear test. The CCP was obtained from a CCP evaporation pond in the Eastern United States, and consisted primarily of silt-sized particles. A series of small-scale vane shear (diameter = 12.5 mm and height = 25 mm) and large-scale vane shear (diameter = 25 mm and height = 50 mm) tests were conducted on CCP. Undrained and drained strength envelopes were determined for CCP using consolidated undrained (CU) triaxial compression tests. Triaxial results were verified via consolidated drained (CD) direct shear tests on similarly prepared CCP specimens and comparing the results with the drained strength envelope. In addition, effects of the following variables on the vane shear strength of CCP were evaluated using the small-scale vane: (i) rate of vane rotation, (ii) time delay between vane insertion and beginning rotation (td), and (iii) elapsed time under the final vertical effective stress prior to shearing (tc). A fine synthetic tailing (FST), which was 100% fine grained with approximately 40% clay-sized particles, was evaluated for comparison via small-scale vane shear. FST was selected as the higher clay content and lower permeability, relative to CCP, made the material more suited for evaluating vane shear with undrained conditions. All test specimens were prepared in the laboratory via the slurry deposition method and consolidated to the target vertical effective stress. Vane shear strength results were compared to drained and undrained strength envelopes for CCP and FST. Vane shear strength results were represented in terms of peak shear strength and the initial horizontal effective stress acting on the vertical-oriented failure surface during vane shear. Vane shear tests on CCP in small-scale vane shear and large-scale vane shear yielded shear strengths that plotted between the drained and undrained strength envelopes. This was explained by the small diameter of the vane and/or high permeability of CCP that allowed drainage to occur during testing. Small-scale vane shear tests on FST yielded shear strengths comparable to the undrained strength envelope, which was justified by the considerably lower permeability of FST relative to CCP. Additional evaluation of small-scale vane shear tests on CCP revealed that rate of rotation and td had no influence on measured peak shear strength. This was attributed to the small vane size and high permeability of CCP, which allowed excess pore pressure to dissipate regardless of how fast the material was sheared. Diagenesis was observed to occur in CCP, whereby time-dependent chemical reactions lead to an increase in strength with time. In small-scale vane shear tests on CCP, peak strength was reached after approximately 72 hr. These vane shear tests that accounted for diagenesis (i.e., were allowed to remain under vertical stress for ≥ 72 hr) were found to be most comparable to the drained strength envelope identified via triaxial and direct shear testing. Thus, accurate measures of peak shear strength in CCP must account for diagenesis to occur.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.Item Open Access Static and dynamic study of metal salt hydrates of weakly-coordinating fluoroanions by vibrational spectroscopy, gravimetry, and an analysis of previously published x-ray structures(Colorado State University. Libraries, 2021) Lacroix, Matthew R., author; Strauss, Steven H., advisor; Chen, Eugene, committee member; Bandar, Jeff, committee member; Ridley, John, committee memberEighteen metal salt hydrates (Li(H2O)4(Al(OC(CF3)3)4), Li(H2O)(B(3,5-C6H3(CF3)2)4), Li(H2O)n(Ga(C2F5)4), Li(H2O)(PF6), Na(H2O)(PF6), Li2(H2O)4(B12F12), Na2(H2O)2(B12F12), K2(H2O)2(B12F12), Rb2(H2O)2(B12F12), Cs2(H2O)(B12F12), Mg(H2O)6(B12F12), Ca(H2O)n(B12F12), Sr(H2O)n(B12F12), Ba(H2O)n(B12F12), Co(H2O)6(B12F12), Ni(H2O)6(B12F12), Zn(H2O)6(B12F12), and Li2(H2O)2(TiF6)) containing weakly coordinating anions were analyzed using room temperature ATR-FTIR spectroscopy. The goal was to investigate the relative strengths of water–anion hydrogen bonds in the solid-state. In all but one case, these hydrogen bonds take the form of O–H···F hydrogen bonds. The one exception is in the salt Li2(H2O)4(B12F12) where there are both O–H···F and O–H···O hydrogen bonds present. Based on the magnitude of the redshift of the ν(OH) band(s) a qualitative scale for the comparison of the relative hydrogen bond strength is constructed. Included in this scale are additional metal salt hydrates taken from the literature. This spectroscopic study has produced some of the only room temperature spectra for water participating in hydrogen bonding in the solid-state where the νasym(OH) and νsym(OH) bands are individually resolvable. The weak nature of the O–H···F hydrogen bonds allows for resolution of ν(OH) bands only 5 cm−1 apart in some cases. The two metal salt hydrates (Li(H2O)4(Al(OC(CF3)3)4) and Li(H2O)(B(3,5-C6H3(CF3)2)4) are shown to possess the weakest O–H···F hydrogen bonds observed in the solid state at room temperature. The salt Li2(H2O)4(B12F12) contains a cyclic (H2O)4 water cluster, also known as the R4 cluster, is presented, and discussed in the context of the FTIR spectrum of water clusters. Due to the nature of the weak O–H···F hydrogen bonding between the cluster and the surrounding anions the E and B fundamental vibrations for the cluster were able to be determined. The peak-to-peak separation, and relative intensities of these two bands are consistent with computational results from the literature. This is the first time that the R4 water cluster has been successfully studied via FTIR spectroscopy without the presence of other clusters leading to ambiguity in the results. Finally, direct observation of the effect of cation acidity on the relative strength of water–anion hydrogen bonding has been directly observed for the first time in the metal hexahydrate salts M(H2O)6(B12F12) (M = Mg, Co, Ni, Zn). These results, along with the correlation curves constructed in this work, show that it is not possible to assign relative hydrogen bond strength based on O–H···X bond length, nor is it possible to accurately approximate O–H···X bond length based on degree of ν(OH) redshift. Instead, it is shown that the relative basicity of the anion is the primary factor governing the relative hydrogen bond strength, and thus the degree of redshifting experienced by the ν(OH) band(s). The cation acidity also is shown to have a lesser, but observable, effect on the relative strength of O–H···X hydrogen bond. In addition to broadening our fundamental understanding of hydrogen bonding in the solid state, this work also shows that FTIR spectroscopy can be a useful tool for rapidly assigning relative basicity of new weakly coordinating anions without need the for complex protonation experiments.Item Open Access Structural evolution and rheology of the Paposo shear zone in the Atacama fault system, northern Chile(Colorado State University. Libraries, 2018) Ruthven, Rachel Courtney, author; Singleton, John, advisor; Magloughlin, Jerry, committee member; Ridley, John, committee member; Bhaskar, Aditi, committee memberTo view the abstract, please see the full text of the document.Item Open Access Structural evolution of the Potosà uplift, Sierra Madre Oriental, northeastern Mexico(Colorado State University. Libraries, 2019) Williams, Stewart Alexander, author; Singleton, John, advisor; Ridley, John, committee member; Laituri, Melinda, committee memberThe Jurassic Minas Viejas Formation is host to a Late Cretaceous to early Paleogene-aged décollement in the Sierra Madre Oriental, Mexico. The Minas Viejas Formation is dominated by rheologically-weak evaporite that accommodated thin-skinned deformation, forming the Sierra Madre Oriental fold-thrust belt with minimal deformation to the underlying Triassic-Jurassic red beds. Thin-skinned shortening above the décollement temporally transitioned to thick-skinned shortening, resulting in exhumation of the décollement and development of the Potosà uplift, one of the largest and well exposed thick-skinned uplifts in the orogen. Detailed geologic mapping and structural analysis provide insight into the geometry and kinematics of the Potosà uplift, and (U-Th)/He thermochronometry and vitrinite reflectance record the burial history and timing of exhumation associated with the uplift. Thick-skinned deformation involved folding of sub-décollement strata into a NNW-SSE-striking anticlinorium, development of cleavage, ENE-WSW directed thrust faulting, conjugate strike-slip faulting, and formation of ENE-WSW-striking extension fractures associated with barite mineralization. These structures consistently record ENE-directed subhorizontal shortening. Shortening is directed ~062° in the southern part of the uplift and ~077° in the northern part of the uplift. Thick-skinned deformation modified pre-existing geometries of thin-skinned folds involving Cretaceous overburden strata above the Jurassic evaporite décollement. Zircon (U-Th)/He cooling dates (ZHe) and vitrinite reflectance data indicate that the entire evaporite décollement was buried to ≥185°C, consistent with development of phyllitic fabrics in the basal part of the Minas Viejas Formation. Paleocene to mid-Eocene zircon (U-Th)/He cooling dates in the Triassic-Jurassic red beds below the evaporite décollement directly record the timing of exhumation associated with thick-skinned deformation, and suggest that the thick-skinned uplift was a continuation of earlier thin-skinned shortening as opposed to a distinct tectonic event. A zircon (U-Th)/He date from the southern Potosà uplift is ~66 Ma, whereas ZHe dates in the northern part of the uplift range from ~49–43 Ma. Two samples from the nearby Aramberri uplift to the south of the Potosà uplift have mean ZHe dates of ~63–54 Ma. The transition from thin- to thick-skinned shortening may be attributed to the evolution of mechanical stratigraphy in the décollement. Thin-skinned detachment folding resulted in significant migration of evaporite away from synclinal keels, effectively eliminating a planar weak zone at the base of the décollement and creating salt welds between carbonates or shales within the décollement with underlying red beds. The along-strike differences in timing of thick-skinned exhumation and the shortening directions may also be attributed to differences in mechanical stratigraphy. Thicker intervals of evaporite in the northern part of the uplift allowed thin-skinned shortening to continue while the southern part of the uplift transitioned to thick-skinned shortening as the weak evaporite décollement was exhausted. As a result, stress-strain trajectories in the northern part of the uplift refracted clockwise towards the area with more propagation of deformation. Our findings provide a new insight into the geometry, kinematics, and timing of deformation associated with the Potosà uplift, and may provide a framework for studying other thick-skinned uplifts in the Sierra Madre Oriental, and more generally orogenic belts that record a transition in deformation styles.Item Open Access Timing, kinematics, and tectonic significance of strike-slip fault systems in the Atacama Desert of northern Chile and the Lower Colorado River corridor, U.S.A.(Colorado State University. Libraries, 2021) Mavor, Skyler, author; Singleton, John, advisor; Gallen, Sean, committee member; Ridley, John, committee member; Laituri, Melinda, committee memberTo view the abstract, please see the full text of the document.