Master of Science / Department of Geology / Saugata Datta / Tungsten (W) has become an element of greater concern in recent years. Investigations by the Centers for Disease Control implicated W as a possible link to several cases of childhood acute lymphatic leukemia (ALL) clusters in the western United States. In Fallon NV, 17 cases of ALL were reported from 1997-2001. Previously, it was difficult to attain knowledge about the geochemical behavior of W due to low concentrations and difficulties in detection in natural environments. Modern analytical techniques allow for a greater range of sensitivity, allowing for in depth W analysis. Elucidating information on the factors contributing to the fate and transport of W in low temperature environments will provide insight into how W moves through the environment and provide information to help mitigate W contamination in the future. Three sites were chosen for comparison of W concentration and how that may be linked to local geochemical factors. Fallon NV, Sierra Vista AZ, and Cheyenne Bottoms Refuge KS were chosen based on published literature and personal communications. The objectives for this study were to characterize W concentrations in these three climatologically distinct areas followed by using methods to speciate and semi-quantitatively characterize W phase association within the surficial sediments and using synchrotron X-Ray methods to define W valencies and elemental associations within the sediments. Tungsten occurs in varying concentrations in the study areas, from 17.8 mg/kg to ~25,907 mg/kg. Fallon has the highest average W concentration of the three sites as well as the highest amount of W associated with phases other than the organic matter or residual phase. Speciation of soluble W revealed no polytungstates, however tungstates are present in the samples as well as undefined W species, suggesting there are other forms of W that are readily soluble in water, hence bioavailable. Tungsten has a very heterogeneous distribution in sediments, creating dispersed but highly concentrated clumps of W hotspots. Spot analyses under X-Ray mapping reveal W may co-localize with other metals such as Ti, Co, and Zn.

Master of Science / Department of Geology / Matthew Brueseke / The Little Goose Creek area is located in Elko County, Nevada just south of the central Snake River Plain and in the northeastern Great Basin. During the Miocene, northeastern Nevada was characterized by volcanism as well as prevalent extension and basin development, including widespread occurrences of porphyritic quartz-phyric silicic lavas and domes (e.g., the Jarbidge Rhyolite), ash-flow tuffs, and basaltic volcanism. Recent workers (e.g., Colgan and Henry, 2010) have provided new constraints on the timing of extension in the northern Great Basin (U.S.A.) and indicate that much of it occurred in the mid-Miocene. Other recent work has provided new temporal and petrologic constraints on 16.1 to 15.0 Ma Jarbidge Rhyolite volcanism in the northern Great Basin west of our study area, and suggest that it is intimately linked (spatially and temporally) with the aforementioned extension. This study aims to: [1] understand the spatiotemporal link between the volcanism in the northeastern Nevada study area and potentially correlative volcanism regionally (e.g., Jarbidge Rhyolite and explosive deposits associated with the <13 Ma Bruneau-Jarbidge or Twin Falls eruptive centers); [2] determine if the sampled Jarbidge Rhyolite lavas are chemically similar to those in and around Jarbidge, Nevada. In the Goose Creek area, we report a new laser [superscript]40Ar/[superscript]39Ar age for sanidine of 13.6 ± 0.03 Ma for a crystal-poor rhyolite lava (Rock Springs Rhyolite) and a Jarbidge Rhyolite lava (13.827±0.021 Ma) as well as an age on Jarbidge Rhyolite in Wells, NV (15.249±0.040 Ma) and West Wendover, NV (13.686±0.034 Ma). These lava samples, as well as sampled ash-flow tuffs from the Goose Creek region, plot within the A-type field on discrimination diagrams. The ash-flow tuffs are younger than the Rock Springs Rhyolite based on stratigraphic relationships and are sourced from both the Twin Falls eruptive center as well as the Bruneau Jarbidge eruptive center of the central Snake River Plain based on geochemical analysis. Also, a sequence of basaltic lavas crop out in the Goose Creek drainage; these basalts have ~43 wt.% silica and are chemically similar to <8 Ma olivine tholeiite basalts that crop out to the north, along the southwestern side of the Cassia Mountains, Idaho. These results, field relationships, and prior geological mapping suggest that the lavas and ash-flow tuffs erupted into active extensional basins.

Master of Science / Department of Geology / Matthew W. Totten / Ness County has contributed 30 billion barrels to Kansas oil production since 1995, and has been an actively developing county in oil activity. The focus of this research project is to identify the reservoir qualities that make Mississippian-aged production favorable. Modern day logging techniques and seismic data allow specialists to seek out subtle heterogeneities to an oil producing formation once thought to be homogenous. Having success with horizontal drilling in other locations worldwide, large oil companies have acquired tens of thousands of acres with the intentions of drilling into the Mississippian, although some have recently backed out of the area. While some horizontal wells are producing today, complications with the compartmentalized, relatively thin Mississippian producing zones and short production longevities make horizontal drilling a high risk technique. Better understanding favorable reservoir qualities are essential for future production and development of oil fields in Ness County. This case study utilizes different variations of post and pre-stack 3D and 2D seismic data shot on about 3,200 acres spanning over 8 sections located in northwestern Ness County. The physical and chemical properties associated with the Mississippian formation in this area can be better analyzed with different methods for processing seismic data. Raw seismic signatures show little variation within the Mississippi Lime/Dolomite. Utilizing Seismic attributes derived from raw data may bring certain featured hydrocarbon bearing zones into view. Attributes such as curvature and coherency aid in interpreting physical features within the study area while spectral decomposition, amplitude, instantaneous frequency, and instantaneous Q hold detailed signatures dependent upon rock properties.

Master of Science / Department of Geology / Matthew W. Totten / Ness County, Kansas is situated along the western flank of the Central Kansas uplift, and has been an active center of oil exploration since the 1920’s. It currently ranks fourth among Kansas counties in oil production, largely from Mississippian-age carbonate reservoirs. Some production has been realized from lower Pennsylvanian-age carbonate formations, although the distribution of these reservoirs appears sporadic. The goals of this study were to develop an exploration model that predicts the development of reservoir conditions within the Marmatonage Fort Scott Limestone. A two-township area was studied to examine relationships between production rates and subsurface variations. No core was available through the Fort Scott, hence drill cuttings were thin-sectioned and examined under a petrographic microscope to see details of porosity type not easily visible under a binocular microscope. Production appears to be defined by stratigraphic variations in porosity controlled by original depositional environment. The best wells are within an oolitic limestone, with subsequent development of secondary, vuggy porosity. These conditions occur in bands along the Mississippian paleo-topographic highs. I interpret these bands to be ancient ooid shoals, with geometries and scales analogous to those previously reported from Lansing/Kansas City reservoirs in Russell County, Kansas. This study provides insights into production trends within the Fort Scott Limestone, and should be included during exploration in Ness County, Kansas.

Master of Science / Department of Geology / Charles G. Oviatt / The Dyer Mountain quadrangle, located in Utah approximately 200 km east of Salt Lake City and 20 km north of Vernal, lies on the south flank of the east-west trending Uinta anticline. The topography of the area varies from mountain peaks to deep canyons, with rolling hills of uplands in between. The elevation in the quadrangle ranges from 3124 m (10248 ft) at the top of Dyer Mountain to 1835 m (6020 ft) at the lowest point of Big Brush Creek. Most of the northern portion of the quadrangle is vegetated by aspens and pines, whereas the southern part of the quadrangle is covered with sagebrush and grasses. Due to its location on the anticline, the quadrangle contains bedrock that dips gently to the south and southeast. The ages of the rocks within the quadrangle range from the Precambrian Uinta Mountain Group to the Quaternary and Tertiary gravels. Also present are the following formations: Cambrian Lodore; Mississippian Madison, Doughnut, and Humbug; Pennsylvanian Round Valley and Morgan; Pennsylvanian to Permian Weber; Permian Meade Peak Member of the Phosphoria and Franson Member of the Park City; and various Quaternary sediments. The Lodore Formation and the Madison Limestone rest on major unconformities, and the Quaternary and Tertiary gravels overlie the Gilbert Peak erosion surface. The Uinta anticline and southerly dip of the Proterozoic and Paleozoic rocks are a result of Late Cretaceous uplift during the Laramide orogeny; Tertiary rocks within the area show little to no deformation. Limestone and various types of ores have been mined in the quadrangle, and phosphorous is currently being mined for fertilizer production. Several landslides, common at the juncture of the Quaternary and Tertiary gravels and Permian shales, were identified within the quadrangle. An anticline and syncline, trending northwest to southeast, lie in the southeast portion of the quadrangle and transect Big Brush Gorge. Geologic hazards of the area include landslides, erosion and failure of road grades, and cliffs near trails. The karst topography of the area presents dangers of sink holes, and evidence of ceiling collapse is present within Big Brush Cave, a popular destination for tourists and cavers.

Master of Science / Department of Geology / Matthew W. Totten / 3D seismic surveys have become the backbone of many exploration programs because of their high resolution and subsequent success for wildcat test wells. There are occasions when the predicted subsurface geology does not agree with the actual geology encountered in the drilled well. A case in point occurred during the drilling of several wells based upon a 3D seismic survey in Ness County, Kansas, where the predicted Cherokee Sand did not meet the expectations. By better understanding the subsurface geologic features in the subject area, this study will attempt to answer the question “what went wrong?” Seismic attribute analysis workflow was carried out and the results were correlated to the available geological and borehole data within the survey boundaries. The objective of running this workflow was to describe facies variations within the Cherokee Sandstone. Correlations between seismic attributes and physical properties from well data were used to define these variations. Finally, Distributions of the seismic facies were mapped to predict the distribution of potential reservoir rocks within the prospect area.

Master of Science / Department of Geology / Matthew W. Totten / The Spivey-Grabs-Basil oil field is a highly developed field in south-central Kansas, having large variability in its production and in the Pineville Tripolite facies. The Pineville Tripolite is the primary producing formation of this field having major isopach variations, possibly influencing production. The hypothesis that the field is highly compartmentalized is from the varied production, isopach and structure of the field. This study investigated the Pineville Tripolite facies in the Spivey-Grabs-Basil Oil Field, with the Basil area the predominant focus, and its possible compartmentalization by looking at the gas chromatograms and their biomarker signatures. This field has had several studies investigating the geophysical attributes, depositional setting and large-scale compartmentalization. Post depositional sea-level changes and possibly syntectonics exposed the Reeds Spring to a sub-aerial environment where meteoric alteration created immense porosity and the Pineville Tripolite facies. Geochemical data shows evidence that this section of the field is sourced from both a marine shale and carbonate source at peak oil maturity, deposited in an anoxic environment. Biodegradation appears very slight, with most alterations transpiring in the alkane ranges only, leaving all other susceptible hydrocarbons unaltered. Compartments within the field are harder to identify when comparing geological data to oil data. Isopach data shows altered thickness of the Pineville Tripolite from well to well, as do Pineville structure values. The isopach and structural data point to possible areas for compartments, but it is from oil geochemical data that compartments become more visible. API gravities and GOR show motley values, but do indicate two significant areas of segregation. The deepest, most southern end of the study showed lighter gravity oils than the middle, suggesting possible fill and spill between the two. However, biomarker abundance indicates three possible compartments. The southern compartment has many more biomarker volumes than do the middle compartment, both divided by a reservoir pinch-out. The third most northeastern well has high biomarker abundance, but shows no geological separators from the other wells. Production from this field may be improved by investigating the biomarkers to allocate these compartments and possible barriers close to wells.

Master of Science / Geology / Matthew W. Totten / The thermal maturity of hydrocarbon-rich source rocks can be estimated by several different methods. These methods focus on a specific geochemical or mineralogical aspect contained within the rock. Because each method has limitations, it is advisable to use several methods to better determine thermal maturation. This report summarizes two common methods used to determine thermal maturity, vitrinite reflectance and illitization. Vitrinite reflectance and illitization have both been shown to be effected by similar temperatures that are within the hydrocarbon generation window. In some previous studies these two methods give different levels of maturation when looked at in tandem. Formations such as the Woodford Shale of Oklahoma are made up almost completely of illite in the clay fraction, even at low levels of vitrinite reflectance. These are also without a clear source of potassium, which is often the limiting factor in the process of illitization. Totten et al. (2013) suggest that in place of potassium feldspars, which are a common source of K⁺ for illite (but lacking in the Woodford) that the needed K⁺ was provided by the organic material that was being altered under the same temperatures of the clay minerals. The Woodford contains large amounts of organic matter, This would be consistent with promoting illitization at lower thermal maturities than organic-poor shales.

Master of Science / Department of Geology / Allen W. Archer / The Morrowan middle Bloyd sandstone of northwest Arkansas records a fluvial to estuarine transition in a drowned incised valley system. Lower portions of outcrops contain fluvially deposited, planar-tabular cross-stratified sandstone with a uni-directional southwest paleoflow. Intervals with dune scale, intricately interwoven trough cross-stratification with northeastern paleoflow is attributed to strong tidal and wave influence in the outer estuary. Upwards the middle Bloyd changes into a muddy mid-estuarine interval with heterolithic bedding and a bi-directional northeast-southwest paleoflow. Overlying this interval a marine sand about one meter in thickness can be found containing bryozoan and crinoid fossils. Overlying the middle Bloyd, the marine Dye Shale member of the Bloyd Formation marks the transition to a dominantly marine setting.

Master of Science / Department of Geology / Matthew W. Totten / Sands rich in volcanic ash have been encountered within the late Cenozoic sequence offshore Louisiana in the northern Gulf of Mexico. These beds are identified on well logs by their high radioactivity and low density. Paleontologic markers used to date these deposits give dates that are consistent with eruptions from the Snake River Plain (SRP) and Yellowstone calderas. Lead isotope ratios from the Gulf of Mexico samples are also consistent with the SRP-Yellowstone tuffs. The objective of this study was to compare the rare earth element (REE) and other trace element data from the GOM samples to determine whether they may be differentiated from one another, and also whether they compare to the SRP data. Well cuttings and sidewall core samples from sixteen wells known to contain volcanic ash were density separated using lithium metatungstate to isolate the low density volcanic glass from the remaining minerals. The concentrated ash was dissolved and analyzed using ICP-MS. Trace and REE variations were plotted by depositional age based upon paleontological markers. Variations in most trace elements are not useful criteria for discriminating ash by age. There is a wide spread in fairly mobile elements (i.e. Sr, Ba), suggesting that each ash bed has had a different diagenetic history. REE variations, in particular the magnitude of the Europium anomaly and the degree of fractionation between light and heavy REE, are good discriminates of each ash. A few anomalous samples plot within an older field, which might be explained by reworking of older ash into younger deposits. Direct correlation to SRP-Yellowstone eruptions is hindered by the lack of SRP samples analyzed using similar methods.