Physical Sciences and Mathematics Commons^™

Evaluating The Use Of Environmental Tracers To Reduce Conceptual Model Uncertainty Of Hydrogeologic Models, Andrew Nordberg, Jon Graham, W. Payton Gardner

Graduate Student Theses, Dissertations, & Professional Papers

Environmental tracer concentrations for CFC12, SF6, and tritium are used in groundwater simulations to assess the ability of these tracers to reduce conceptual model uncertainty due to uncertainty of a site’s geologic and recharge characterization. The resulting groundwater simulations are characterized by site-specific hydrologic and geologic data, and with coordination from a field team with years of knowledge about the site. First-order (conceptual) uncertainty is directly addressed by using a stochastic modeling approach for spatial variability of the proposed subsurface configurations. Simulations of environmental tracer concentrations and water levels are used to assess six alternate conceptual models that are based …

Investigating Elastic Deformation Induced By Surface Loads On Planetary Bodies, Ashlesha Khatiwada, Hilary Martens, Donald F. Argus

Graduate Student Theses, Dissertations, & Professional Papers

Planetary bodies, including the Earth, deform when there is a redistribution of surface load. In this thesis, I conduct three independent projects related to surface loading, two of which investigate methods related to the modeling of surface loading and one which seeks to catalog the displacement responses of other planetary bodies to a surface load.

The first project aims to compare four methods for modeling the elastic loading response of the Earth: a homogeneous, non-gravitating, half-space method; a homogeneous, gravitating, spherical method; a homogeneous, non-gravitating spherical method; and a radially stratified gravitating spherical method. Many studies have focused on computing …

Synthetic Aperture Radar Observations At Salar De Pajonales, Chile, Michael A. A. Mcinenly

Graduate Student Theses, Dissertations, & Professional Papers

Remotely sensed microwave radars provide the spatial and temporal coverage needed to improve our understanding of the relationship between moisture content and salt pan mineralogy and, ultimately, climate variability. Moisture content in the surface and near-surface crusts found in salt pan environments, such as salt pan, has a significant impact on the backscatter values recorded by synthetic aperture radar (SAR) systems. This is because moisture affects the dielectric constant and surface roughness of the saline surface, which in turn influences the amount of electromagnetic energy reflected back to the SAR sensor. Changes in backscatter values are attributed to seasonal and …

Petrogenesis And Tectonic Implications Of Cordierite-Orthoamphibole Gneisses (Cog) In The Nw Wyoming Province, Brianna K. Crenshaw Ms

Graduate Student Theses, Dissertations, & Professional Papers

Studying cordierite orthoamphibole gneisses (COG) from five different mountain ranges across the Montana Metasedimentary Terrane (MMT) of the Wyoming Province offers a unique opportunity to elucidate the enigmatic origins and petrogenesis of the lithology in addition to gaining a further understanding of Precambrian crustal assembly processes. Geochemical analyses suggest that COG originates from a basalt that underwent metasomatic alteration, likely via seawater, prior to metamorphism. Moreover, COG is considered to represent oceanic crust that was part of the epicontinental sea adjacent to the Wyoming Province before collision with the Medicine Hat Block. Field observations of associated lithologies such as marbles, …

Diagenesis Of The Lower Permian Wolfcamp Formation, West Texas: Implications For Reservoir Quality In The Midland Basin, Kory John Talcott

Graduate Student Theses, Dissertations, & Professional Papers

This study focuses on documenting the diagenesis and pore evolution within the lower Permian Wolfcamp B Formation in two producing wells from the Midland Basin of west Texas. Both wells are located near the northeastern margin of the Midland basin, with well A located proximal to the basin margin and well B located about 20km down depositional dip. The entire Wolfcamp B interval has been cored from both wells.

In both wells, the Wolfcamp B consists of calcareous and siliceous mudstone, skeletal wackestone, packstone, grainstone, rudstone, and floatstone facies that were deposited below wave base by a combination of suspension …

A Record Of The Precambrian-Cambrian Transition In Sw Montana: A Late Neoproterozoic To Early Cambrian Stratigraphic Window, Fortunian Biostratigraphic Assemblage And Treptichnus Pedum, R. Reid Trippe

Graduate Student Theses, Dissertations, & Professional Papers

This study documents a Late Neoproterozoic through Early Cambrian stratigraphic record in the Humbolt anticline of southwestern Montana. The Precambrian-Cambrian transition includes a Fortunian-aged biostratigraphic trace-fossil assemblage with the ichnofossil Treptichnus pedum. The Humbolt anticline represents an inverted paleo-graben that exposes a stratigraphic window interpreted to be a record of rifting along the Cordilleran miogeoclinal margin, linked with the breakup of the Rodinia supercontinent. The graben subsided and captured sediment during late-stage rifting and final-stage dissociation along the rift margin. Its structural axis paralleled the rift margin. Sevier/Laramide orogenic thrusting inverted the graben into the Humbolt anticline. The Late …

Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter

Graduate Student Theses, Dissertations, & Professional Papers

The Ruby Range in southwestern Montana is a fundamental location within the Archean Wyoming craton for examining Precambrian crustal architecture and determining the thermotectonic evolution of the region. Monazite, zircon, and garnet geochronology from each of the three major units within the Ruby Range reveal two distinct metamorphic age populations: an older population ca. 2.55-2.45 Ga (the Tendoy orogeny) and a second, younger population ca. 1.78-1.72 Ga (the Big Sky orogeny). Phase equilibria modeling for the Big Sky orogeny within the confines of the Mine Gulch 7.5’ quadrangle reveal discrete pressure-temperature (P-T)histories for each of the three major …

Facies Architecture And Controls On Reservoir Behavior In The Turonian Wall Creek Member Of The Frontier Formation, Powder River Basin, Wyoming, Nathan M. La Fontaine

Graduate Student Theses, Dissertations, & Professional Papers

Inter-well heterogeneities influencing fluid migration in deltaic reservoirs are controlled by lateral lithofacies changes and vertical complexities such as low permeability thin-beds. Subsurface tools often cannot predict the spatial and stratigraphic organization of these architectural elements, nor their influence on effective reservoir properties and connectivity. This study integrates sedimentological, stratigraphic, and fluid simulation data to 1) document the facies architecture and depositional evolution of the Turonian Wall Creek Member (WCM) of the Frontier Formation, and 2) quantify the role of multi-scale stratigraphic heterogeneity on reservoir behavior. Upscaled permeability properties derived from fluid simulation of nested, small-scale facies models condition the …

Insights Into The Proterozoic To Cretaceous Evolution Of The Western Clearwater Metamorphic Core Complex, Northern Idaho, Through Petrologic And Geochronologic Analysis, Nora Dwyer

Graduate Student Theses, Dissertations, & Professional Papers

The Clearwater metamorphic core complex (CMCC) in northern Idaho contains a rare exposure of the contact of the basal section of the Mesoproterozoic Belt Supergroup with underlying Paleoproterozoic basement. Prior to this study, this contact had not been well documented. In addition, the rocks within the CMCC preserve a complex history of metamorphism, including both Mesoproterozoic and Cretaceous-Eocene regional events. Detrital zircon analysis of five coarsely recrystallized, clean quartzite samples at this contact reveal a bimodal age distribution with peaks at around 1800 - 1900 Ma and 2650 Ma. Several grains are younger than 1700 Ma, with the youngest being …

Lateral Heterogeneity And Architectural Analysis Of The Wall Creek Member Of The Upper Cretaceous (Turonian) Frontier Formation, John Zupanic

Graduate Student Theses, Dissertations, & Professional Papers

The Upper Turonian Wall Creek Member (WCM) of the Frontier Formation is part of a series of marine sandstones that were deposited on the western flank of the Cretaceous Western Interior Seaway (KWIS). The KWIS was a low accommodation shallow-marine foreland basin system that included many large deltaic complexes on its western margin. Deposition of WCM deltaic deposits was strongly influenced by fourthorder glacioeustatic cycles, oceanographic circulation patterns, and tectonics related to the active Sevier fold and thrust belt to the west. An in-depth field study of the WCM was performed on the western flank of the Powder River Basin …

Structural Analysis Of A Triangle Zone Culmination, Comb Rock, Lewis And Clark County, Montana, Shane S. Fussell

Graduate Student Theses, Dissertations, & Professional Papers

A triangle zone is a structure commonly found at the leading edge of a thrust belt, characterized by a triangular cross-section of thrust faults. In the Montana triangle zone, west-dipping thrust faults intersect east-dipping ones above a regional detachment fault. Most studies of triangle zones focus on the structure in a cross-sectional sense, but little work addresses variations along the trend. The Canadian Rocky Mountain triangle zone has long been a productive petroleum province, so understanding the southern extent of this zone, where it enters Montana, is of interest for economic purposes as well as geologic understanding. Previous studies have …

Hazardready – A Geographically Based Natural Hazard Education And Preparedness Web Application, Carson C. Macpherson-Krutsky Ms.

Graduate Student Theses, Dissertations, & Professional Papers

Earthquakes, floods, wildfires, and other natural disasters are inevitable and costly both in terms of lives lost and money spent on recovery. Scientific research on natural hazards is widely shared within the scientific community, but is less often made more widely accessible, as methods or pathways for providing scientific natural hazard information and data in non-technical language are limited. Priorities for imparting hazard information include: 1) scientific accuracy, 2) spatial granularity, 3) integration of information about all relevant hazards, 4) nontechnical content, 5) appropriate preparedness activities, and 6) engagement with existing disaster response and mitigation capabilities. In response to these …

Kinematic Constraints On Tectonics Of The Northern Basin And Range, Dylan Schmeelk

Graduate Student Theses, Dissertations, & Professional Papers

We derive surface velocities relative to North America, using data from 1989 through 2014 in the interior northwest, to investigate kinematics from the Snake River Plain (SRP) to the Canadian border. The Centennial Tectonic Belt (CTB) exhibits similarities to the main Basin and Range Province (BRP) that suggest the CTB is an extension of the BRP, including range and fault orientation, increasing velocity magnitudes westward, and a distinct high rate of strain across the Madison Range. Calculations of fault spreading rates and orientations from geodetic data show that several faults are more active than previously assumed when compared to seismic …

Facies, Architecture, And Sequence Stratigraphy Of The Devonian-Mississippian Sappington Formation, Bridger Range, Montana, Anna S. Phelps

Graduate Student Theses, Dissertations, & Professional Papers

The Late Devonian-Early Mississippian Sappington Formation in Montana is a marine unit comprised of lower and upper organic-rich shale members and a middle calcareous siltstone member. The Sappington Formation was deposited during a period of complex paleogeography in Montana, characterized by deposition in sub-basins and onlap onto structural highs, and eustatically- and tectonically-driven transgressive-regressive cycles. Detailed outcrop analysis was conducted on the Sappington Formation across the Bridger Range in southwestern Montana to better understand the Sappington Formation depositional system and changing regional paleogeography. The Sappington Formation is further interpreted in a stratigraphic architectural framework to improve the ability to predict …

The Neocene Lake Beds Of Western Montana And Descriptions Of Some New Vertebrates From The Loup Fork, Earl Douglass

Graduate Student Theses, Dissertations, & Professional Papers

Since coming to Montana in the spring of 1894 I have spent rnuoh of ay time in studying the lake bed deposits in the western part of the state, and in collecting and studying the vertebrate fossils found in them. These deposits occur in nearly every large valley in the westem part of the state. I have myself observed them in the valleys of the upper Missouri (above the re-rrion of Helena), Gallatin, Madison, Jefferson, Beaverhead, Ruby, Big Hole, Hell Gate, and Bitter Boot rivers, and their tributaries.