Geology Commons^™

A Study On Photodegradation And The Fate Of Pyrogenic Carbon, John Thomas Howell

Master's Theses

Accounting for all possible sources of atmospheric CO₂ is a pressing issue today due to the increasing effects of climate change. Estimates suggested that on the order of 1.3 million tons of dissolved pyrogenic carbon (pyDOC) could be entering the northern Gulf of Mexico annually. Assessing the fate of pyDOC in aquatic systems is crucial to understanding ecosystem impacts and potential feedback to climate change. Current research indicates that despite a generally lower susceptibility to biodegradation than their unpyrolyzed equivalents, pyrogenic carbon is not environmentally inert. While the role of microorganisms on the fate and transformation …

Controls On Dissolution Rate Variation At A Pair Of Underflow-Overflow Springs At The Savoy Experimental Watershed, Kiefer Allen Vaughn

Graduate Theses and Dissertations

Physical dissolution experiments and numerical modeling have been used in the past to study limestone dissolution rates. Numerical models have typically used constant dissolution rates, whereas rates in nature vary in time. Limestone tablets allow natural estimation of rates over month time scales, but these rates cannot necessarily be extrapolated to geologic timescales and also do not aid our understanding of short term variability. This study characterizes natural variability in these rates and examines potential causes of that variability from first principles. This may enable more accurate projections of dissolution rates within models. This study combines measurement of physical and …

On The Temporal Evolution Of Long-Wavelength Mantle Structure Of The Earth Since The Early Paleozoic, Shijie Zhong, Maxwell L. Rudolph

Geology Faculty Publications and Presentations

The seismic structure of the Earth’s lower mantle is characterized by a dominantly degree-2 pattern with the African and Pacific large low shear velocity provinces (i.e., LLSVP) that are separated by circum-Pacific seismically fast anomalies. It is important to understand the origin of such a degree-2 mantle structure and its temporal evolution. In this study, we investigated the effects of plate motion history and mantle viscosity on the temporal evolution of the lower mantle structure since the early Paleozoic by formulating 3-D spherical shell models of thermochemical convection. For convection models with realistic mantle viscosity and no initial structure, it …

Interpretation Of Late Cretaceous Volcanic Mounds And Surrounding Gulfian Series Formations Using 3d Seismic Data In Zavala County, Texas, Laura Claire Bennett

Graduate Theses and Dissertations

The Late Cretaceous Gulfian series is a prominent and important series across the State of Texas that has been extensively studied since the nineteenth century. It is composed of series of southeast-dipping shelf carbonates and clastics deposited on the northwest margin of the Gulf of Mexico Basin. In south Texas, the Gulfian series was deposited in the Rio Grande Embayment and Maverick Basin and is comprised of the Eagle Ford Group, Austin Group, Anacacho Limestone, San Miguel Formation, Olmos Formation, and Escondido Formation that crop out and continue basinward in the subsurface. Late Cretaceous volcanism formed volcanic mounds composed of …

Unraveling Controls On Fracture Stratigraphy In Carbonates: The Influence Of Regional Stress, Mechanical Properties, And Diagenesis, Matthew H. Peppers

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Fracture characteristics analyzed from outcrops provide key insights into the migration pathways of subsurface hydrocarbons, and allow for a detailed understanding of the tectonic history in an area. This study looks to assess the impacts that various controlling factors have on the development of fracture characteristics. To complete this objective, a succession of Ordovician to Mississippian rocks was examined. The logged section includes the Cotter Dolomite, Chattanooga Shale, St. Joe Formation, and the Boone Formation (subdivided into informal Upper and Lower members). Located in northwestern Arkansas and southwestern Missouri, data were collected from roadcut exposures along Highway 71. Collected fracture …

Stratigraphy And Depositional Environment Of The Mesaverde Group In The Northern Bighorn Basin Of Wyoming, Gordon Adams

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

A sedimentological, stratigraphical and palynological study was conducted on the upper Cretaceous (Campanian) Mesaverde Group over 27.5 km of a north-south-orientated outcrop belt in the northern Bighorn Basin, Wyoming. During the Campanian, the study area lay in the western part of the Cretaceous Western Interior Seaway. The study aims to provide a stratigraphic and paleoenvironmental analysis of the Mesaverde Group and to integrate findings with data from outcrop belts to the south (southern Bighorn Basin), north (Montana) and east (Powder River Basin).

The Mesaverde Group (371 - 515 m thick) comprises a succession of mainly coarsening-upward stratal cycles, with some …

Using Kriging, Cokriging, And Gis To Visualize Fe And Mn In Groundwater, Crystal Johnson

Electronic Theses and Dissertations

For aesthetic, economic, and health-related reasons, allowable concentrations of iron (Fe) and manganese (Mn) found present in drinking water are 0.3 mg/L and 0.05 mg/L, respectively. Water samples taken from private drinking wells in the rural communities within Buncombe County, North Carolina contain amounts of these metals in concentrations higher than the suggested limits. This study focused on bedrock geology, elevation, saprolite thickness, and well depth to determine factors affecting Fe and Mn. Using ArcGIS 10.2, spatial trends in Fe and Mn concentrations ranges were visualized, and estimates of the metal concentrations were interpolated to unmonitored areas. Results from this …

Using Geometric Morphometrics To Differentiate Lower First Molars Of Microtus Species: A Review Of The Clark’S Cave Bone Deposit, Va, Mark Shelleman

Electronic Theses and Dissertations

Clark’s Cave contains a large collection of late Pleistocene mammal material. In particular, it contains a sizable amount of Microtus spp. which can be valuable paleoclimate indicators. Identification techniques traditionally used to classify these species have been shown to be unreliable. Recent studies have shown that using geometric morphometric techniques on lower first molars can be more successful. By placing landmarks and running a discriminate analysis on new and previously collected material from the cave, significant differences in Microtus species proportions were found. Specifically, showing the deposit has a larger proportion of M. xanthognathus than previously reported; resulting in a …

Basic Guide For Description Of Cuttings From Boreholes In Nebraska, Dana P. Divine, R. M. Joeckel, Jesse T. Korus

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

An Investigation Of 3d Seismic Deep Basement Events In Osage County, Oklahoma, Kevin Matthew Liner

Graduate Theses and Dissertations

Deep basement events seen in 3D seismic surveys located in Osage County, Oklahoma can be observed and may have affect overlying sedimentary formations. The 3D surveys used in this study are on the Chautauqua platform about fifty miles northwest of Tulsa, Oklahoma. Stratigraphy of the work area spans base of the Permian to Precambrian formations, with basement depth averaging around 5000 ft in the area of the 3D seismic surveys. Cores spanning Precambrian to Pennsylvanian were examined in the area of the 3D seismic surveys. Hydrothermal minerals were observed in Mississippian age cores. The basement events where tracked using OpendTect …

Toolstone Use In Ozark Prehistory: Assessing Adaptations To A Lithic Dichotomy In The Boston Mountains And Springfield Plateau, Luke Allen Morris

Graduate Theses and Dissertations

Toolstone use in the Ozark Mountains is a reactionary process reliant on how the landscape provides or constrains chipped stone for prehistoric populations. These technological adaptations are recognized at sites throughout the area, but no regional assessment of lithic assemblages provides answers as to why certain stones are used at a particular location. This thesis employs a five step mass analysis of lithic assemblages, and GIS visualizations to observe how the organization of stone technologies vary based on location within contrasting geologic contexts. The chert-bearing Springfield Plateau, and the Boston Mountains with siltstone, are two neighboring dichotomous landscapes that illustrate …

Geologic Controls On Oil And Gas Accumulation And Production From Missourian Stage Granite Wash Reservoirs In The Western Anadarko Basin, Wheeler County, Texas, Derrell Mathis

Graduate Theses and Dissertations

Up-to-date regional and local Granite Wash data of any form is either too scarce to reference or highly privatized by exploration and production companies operating in the region. The objective of this research is to correlate horizontal production data with mapped depositional trends from Upper Pennsylvanian (Missourian Stage) Granite Wash reservoirs in the Western Anadarko Basin in northeastern Wheeler County, Texas. The correlation of raster logs to define various trap type and geometries in Missourian Granite Wash reservoirs of Wheeler County, Texas is used to understand the geologic controls on oil and gas accumulation and production. The analysis includes detailed …

Subsurface Fluid Flow Through The Mississippian Section Of North-Central Oklahoma, Carolyn Brown

Graduate Theses and Dissertations

This study consisted of using drill stem tests, seismic amplitude data, and well logs to create the parameters needed to construct a groundwater flow model for a portion of Osage County. At the start, a potentiometric map of Osage County, Oklahoma was generated to use as a basis for the initial hydraulic heads and the constant heads in the model. Next, three seismic amplitude images were produced in a seismic interpretation program, OpenDtect, to base the hydraulic conductivity values on. In addition, utilizing Gamma Ray on 12 separate wells east-west across the county, a structural cross-section was created within Petra. …

Terrestrial Impacts Of The Central Atlantic Magmatic Province On Western Pangea, Todd Kenneth Knobbe

Graduate Theses and Dissertations

Earth's climate is predominantly controlled by the fluctuation of greenhouse gases, specifically CO2 and CH4, over geologic time. The late Triassic is a period of abrupt climate change that has been associated with a disruption to the global carbon cycle due the emplacement of the Central Atlantic Magmatic Province (CAMP). Evidence has shown that this global carbon cycle perturbation may be the culprit for the end-Triassic extinction. The Whitmore Point Member of the Moenave Formation is a lacustrine deposit with a disputed age of either late Triassic or early Jurassic and currently no absolute dating techniques can be applied to …

Modeling Background Radiation Using Geochemical Data, Kara Marsac

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerial gamma ray surveys have many applications in geology and science in general, such as locating mining prospects, defining radioactive plumes, and detecting nuclear weapons. Unfortunately there is currently no simple way to separate the natural gamma radiation of soil and rocks from that of contaminants such as radioactive plumes. This project used geochemical data (uranium, potassium and thorium concentrations) collected from national databases, private companies, and the NURE (National Uranium Resource Evaluation) Survey, to create forward models of exposure rates measured by aerial gamma ray surveys. We developed these techniques using an area in north central Arizona known as …

Carbon Isotope Variations Associated With A Middle Ordovician Karstic Unconformity, Patricia Suzanne Williams

UNLV Theses, Dissertations, Professional Papers, and Capstones

Large negative carbon isotope (δ¹³C) excursions have been documented from late Neoproterozoic-Paleozoic successions. These δ¹³C excursions have been widely used for regional and global stratigraphic correlation, particularly in strata with limited paleontological and radiometric age controls. Recent studies, however, argued that some negative δ¹³C excursions from stratigraphic record may have been resulted from meteoric/burial diagenesis, which commonly shifts both carbon and oxygen isotopes toward lower values. Testing the diagenetic origin of δ¹³C excursions in stratigraphic successions without independent stratigraphic framework has been difficult because it evolves into circular arguments about stratigraphic completeness …

Going With The Flow Or Against The Grain? The Promise Of Vegetation For Protecting Beaches, Dunes, And Barrier Islands From Erosion, Rusty A. Feagin, Jens Figlus, Julie C. Zinnert, Jake Sigren, Marisa L. Martínez, Rodolfo Silva, William K. Smith, Ashley Cox, Daniel Cox, Donald R. Young, Gregory A. Carter

Faculty Publications

Coastlines have traditionally been engineered to maintain structural stability and to protect property from storm‐related damage, but their ability to endure will be challenged over the next century. The use of vegetation to reduce erosion on ocean‐facing mainland and barrier island shorelines – including the sand dunes and beaches on these islands – could be part of a more flexible strategy. Although there is growing enthusiasm for using vegetation for this purpose, empirical data supporting this approach are lacking. Here, we identify the potential roles of vegetation in coastal protection, including the capture of sediment, ecological succession, and the building …

Comparing Slug Test Methods For Unconfined Aquifers, Hussain Jaber Alfaifi

Dissertations

Slug test methods are used to determine in situ aquifer hydraulic conductivity (K) more quickly and economically than a pump test can. This study compares slug test methods for unconfined aquifers, looking at how to conduct a test using a physical slug, and at different analysis methods including Bouwer and Rice (1976), Kansas Geological Survey (KGS 1994), Hvorslev (1951) and Dagan (1978). Questions that motivated this study include: How well does the Bouwer and Rice method work? What is the most effective way to conduct a slug test? Does using a large physical slug relative to the well diameter and …

Analysis Of Paleokarst Sinkholes In The Arkoma Basin Using 3-D Seismic, Michael Kumbalek

Graduate Theses and Dissertations

Paleokarst features are important to understand, both with regards to research geologists and to the petroleum industry. In terms of geology, understanding paleokarst features can yield more information about the depositional and surface environments of past times, and how diagenetic alteration affected the environment during the formation of karst features. In the petroleum industry, paleokarst features can have positive or negative consequence resulting in a potential reservoir with enhanced porosity due to the paleokarst features, or as a geo-hazard to prepare for or avoid when drilling.

Inspired by issues faced when drilling in the Ft. Worth basin, this study utilizes …

Trace Element Variations In A Stalagmite From Southwest Mexico: Implications For Paleoclimate, Chad Michael Crotty

UNLV Theses, Dissertations, Professional Papers, and Capstones

The combination of stable isotope and trace element concentrations in speleothems has been shown to be a valuable indicator for interpreting paleoclimatic conditions. Anomalous spikes in trace element concentrations have also been shown to indicate anthropogenic environmental changes to the surface, such as deforestation events. In this study, trace element concentrations (24Mg, 25Mg, 84Sr, 88Sr, 137Ba, and 238U) of a stalagmite (JX-6) from Juxtlahuaca Cave, in southwestern Mexico, were measured using an inductively coupled plasma mass spectrometer (ICP-MS). These trace element concentrations were compared to previously analyzed δ18O and δ13C values from JX-6, and to the results of previous studies …