Earth Sciences Commons^™

Volatile Cycling And Metasomatism In Flat-Slab Subduction Zones Of The Central Andes, Coleman Hiett

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Flat-slab subduction, where an oceanic plate subducts horizontally below a continental margin for hundreds of kilometers, is an enigmatic but prevalent tectonic configuration in which chemical cycling and alteration of the continental plate is poorly constrained. Geochemical investigations in regions of modern and ancient flat-slab subduction in the Central Andes afford an opportunity to study this process. Certain elements naturally occur with varying number of neutrons in their nuclei (isotopes), and measurements of isotope ratios within geologic materials inform on chemical sources and geologic processes. This research leverages stable isotope analyses and other geochemical tools to investigate volatiles and other …

Practical Improvements For Pivot And Surface Irrigation, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Irrigation is critical to meeting global food and fiber demands. Optimizing agricultural irrigation may help sustain production levels, while reducing its demand for water. This research evaluated precision sprinklers and drip irrigation for pivots, five pivot track mitigation tools, three scientific irrigation scheduling (SIS) methods, sensors for surface irrigation cutoff, and automating surface systems to implement surge irrigation. With pivots and surface irrigation being the most common methods for irrigation in the West, small improvements from these tools could result in significant water savings.

Low energy precision application (LEPA) sprinklers and mobile drip irrigation (MDI) were tested on two pivots. …

Daytime Versus Nighttime Sprinkler Irrigation Of Two Urban Crops In A Semi-Arid Climate At High-Elevation, Samikshya Pyakurel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nighttime irrigation scheduling is a longstanding water conservation approach to reduce evaporative losses in Utah's semi-arid, urban landscapes. However, residential demand now exceeds system capacity, and the efficiency of the practice has come under question. Therefore, the objectives of this study include: 1) quantify whether a water savings exists between day and night irrigation with a water balance and energy balance approach, and 2) analyze microclimate and crop quality effects to determine any changes to evaporative demand or plant stress by irrigation timing. In 2019, we established 12 field plots in North Logan, UT (41.77° N, -111.81° W, 1380 m …

Pleistocene Deposits Of Lower Wahweap Creek And Its Tributaries, Southern Utah, Noah Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The famous landscapes of the Colorado Plateau have been created over millions of years, primarily by erosive forces of wind and water. Interruptions in the long-term erosion of the landscape occur when streams gain more sediment than they can transport, which causes deposition along channels and floodplains. The resulting sequences of terrace deposits are used by geologists to study when and how river systems have evolved.

Mammoth bones were recently discovered in stream deposits along Wahweap Creek, a tributary of the Colorado River in southern Utah. Previous work indicates that the deposits pre-date the last ice age, making it one …

Late Pleistocene Piedmont Records In The Grand Staircase Region, Southern Utah, Alexander K. Short

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Today the climate in the southwestern United States is arid, characterized by desert landscapes and habitats, periods of drought, and arroyo streams that frequently fill with, and erode, through fine riverbed sediments. A series of cliffs and benches rising from the Grand Canyon to the southern plateaus of Utah, known as the Grand Staircase - home to Kodachrome Basin State Park, Bryce Canyon, are a classical example of this environment as we know it today. However, a record spanning the past 300 thousand years is preserved on the steps of the staircase indicating periods in the past where the climate …

Bedrock Geology Map Of The Naomi Peak 7.5' Quadangle, Cache County, Utah And Novel Age Constraints On Its Cambrian Strata, Hannah R. Cothren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geologists use various “rock-clocks” in order to interpret the timing and tempo of events in Earth’s history. These include global geochemical events in the oceans (chemostratigraphy), the evolution of certain fossil species (trilobite biostratigraphy), and the radiogenic decay of uranium to lead in certain mineral such as zircon (U-Pb geochronology). Integrating these methods in the stratigraphic record in one location can provide a well-constrained timeline for a select part of the Geologic, or Deep Time, record. This technique is especially important in the Cambrian Period (538.8 to 486.9 million years; Ma), which sets the stage for life today with the …

Investigating The Use Of Quartz Luminescence And Rock-Color Alteration To Characterize Wildfire Exposure; Applied To The 2020 Mangum Fire, Kaibab Plateau, Arizona, April I. Phinney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildfires appear to be increasing in size, severity, and frequency. Land managers need information on past wildfire behavior to make effective and adaptive land management plans. However, there are only a few techniques and data sources that provide information on past fire heating. This study aims to provide new methods to equip managers with a more robust understanding of historic and modern fire behavior. Fire behavior is assessed using novel methods that can assess soil and rock response to past wildfire heat exposure.

This study examined samples from the 2020 Mangum Fire, in northern Arizona. Sediment and rock were gathered …

Natural And Experimental Slow Slip Observed Along Shallow Hematite Faults, Alexandra A. Dimonte

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fault slip relieves stress in the shallow crust by slipping suddenly during earthquakes, but some faults also slip slowly in between earthquakes. Exhumed faults, brought up to the Earth’s surface from depth, preserve a record of fault processes and slip rates informed by fault rock structures, textures, and chemistry. Hematite, a common iron oxide mineral that precipitates on fault surfaces, exhibits crystal textures that potentially indicate past slip rate. Hematite can be dated using the radioisotopic system of (U-Th)/He thermochronometry, which constrains the time when He is trapped within a crystal, a process that is a function of temperature. Exhumed …

Holocene Chronostratigraphy Of Dune Fields In Southern Utah: Geomorphic Record Of Past Aridity In The Central Colorado Plateau, Harriet S. Cornachione

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The southwestern United States is characterized by dry climate, and droughts are common. The region is currently in an extreme drought that began in 2000 CE and has lasted longer than any previous drought in at least 500 years. Models predict greater future climate extremes under human-caused climate change. Understanding of the natural range of climate variability is important to put these changes in context. Sedimentary archives of past sand dune activity can help extend the available instrumental observations (last century) and tree-ring records (last millennium).

Sand dunes are landforms that are sensitive to aridity and decreased vegetation cover. They …

Urban Soil Chemical And Nutrient Management Issues Facing Emerging Small Grower Enterprises In Utah, Frank E. Oliver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Knowledge of both soil quality and contamination has become increasingly important with the growth of urban agriculture in Utah and the United States as whole. Land is also a common limiting factor in urban agriculture, so it is important to maximize yield and net returns. In order to meet these demands, three studies were conducted across key urban agriculture sites along the Wasatch Front: 1) an urban soil survey to assess soil contamination, 2) an urban soil survey to evaluate macronutrient and salinity levels, and 3) a nitrogen fertilizer management trial for dahlia (Dahlia pinnata), a cut flower …

Evaluation Of The Geothermal Potential Of The Camas Prairie, South-Central Idaho, Connor J. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The area studied in this thesis was assessed based on the analysis of a water sample collected from the exploratory well USU Camas-1. The water sample was characterized and compared to other water samples collected and analyzed during a previous phase of this project according to its water chemistry.

Lithologic, geophysical, and temperature logs were also used to assess the study area. The depth sensitive data was analyzed to determine the characteristics of the formation as they relate to the favorable parameters of a geothermal resource, those being permeability of the subsurface, heat, and the presence of a clay seal. …

Shallow Composition And Structure Of The San Gabriel Fault, California In Drill Core And Geophysical Logs: Implications For Fault Slip And Energetics, Kaitlyn A. Crouch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthquakes are the sudden and intensive release of energy due to slip along faults. This energy may be felt on the Earth’s surface and may cause displacement of the Earth’s crust (seismic slip). As an earthquake ruptures, rocks in and around the fault are damaged and altered. When a fault displaces without earthquakes, it is referred to as aseismic creep. Faults may experience both seismic slip and aseismic creep throughout their cycles. In order to better model earthquake hazards and understand the cause of seismic slip versus aseismic creep in the shallow crust, we need to characterize the properties of …

Fingerprinting Paleo-Groundwater Sources Using Stable Oxygen And Iron Isotopes Of Iron Oxide Concretions From The "Boiler Room", Moab Area, Utah, Connor Frederickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Isotopes are naturally occurring atoms of an element that vary in the number of neutrons present in their nuclei, resulting in different atomic masses. The most common stable isotopes of oxygen are oxygen-18 (¹⁸O) and oxygen-16 (¹⁶O). Geochemical processes, such as the formation of a solid mineral from dissolved elements in a fluid, can result in preferential concentration of one isotope over the other in a process known as fractionation. By measuring the ratio of ¹⁸O and ¹⁶O in solid minerals and using known fractionation values, the isotopic ratio of the fluid from which …

Lithological And Geochemical Characterization Of Ramp Sediments And A Depositional Model Of The Ordovicain Garden City Formation, Northeastern Utah, Kenneth W. Kehoe

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Ordovician Garden City Formation is a mostly marine limestone rock formation deposited in what is known today as the Northern Utah Basin in North America ~485.5 million years ago. Previous research on the Pogonip Group, a time equivalent rock formation located in the Ibex Basin south of the Northern Utah Basin, has identified nine cycles of sea-level fall and rise. However, these nine sea-level cycles have proven difficult to identify within the Garden City Formation due to the limited contrast between rock types within the rock formation. Previous research on the Garden City has approximated these sea-level cycles through …

Multi-Proxy Approach To Robustly Capture Earthquake Temperature Rise At The Punchbowl Fault, California, Emma M. Armstrong

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthquakes produce heat along a fault surface from friction created as two blocks of rock move past each other. The amount of heat generated depends on a variety of factors, including rock type, stresses, and thickness of the fault zone. Identifying evidence for and quantifying this earthquake (coseismic) temperature rise are essential for identifying past earthquakes in the rock record. Indirect methods, such as textures and geochemical signatures that change with temperature, can serve as paleothermometers. Here we compare two paleothermometers, biomarkers and thermochronometry, from two transects across the Punchbowl fault (PF), California. The PF is an ancient fault strand …

Geologic Characterization Of The Nonconformity Interface Using Outcrop And Drillcore Analogs: Implications For Injection-Induced Seismicity, Kayla Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Starting around 2009, a greater number of earthquakes than anticipated have occurred in the midcontinent region of the United States. These earthquakes have been linked to increased rates and volumes of wastewater injection at several km’s depth into the Earth’s crust near a contact between crystalline metamorphic or igneous rock and overlying sedimentary rock, known as a nonconformity. While much is known about why these new earthquakes occur, comparatively little is known about the physical and chemical rock properties because the nonconformity contact is primarily buried under km’s of sedimentary rock in the midcontinent region. These rock properties are important …

Nitrogen Fertilizer Showed Little Effect On First- And Second-Year Corn Yield And Quality Following Alfalfa, Bailey Brent Shaffer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Silage corn (Zea mays L.) following alfalfa (Medicago sativa L.) is a common crop rotation in Utah and southern Idaho. This is done, in part, to take advantage of residual nitrogen (N) fixed by bacteria that work in symbiosis with the roots of alfalfa. After alfalfa is terminated, much of the N that was fixed by the plant is released into the soil and becomes available for use by the rotational crop. This reduces the amount of N fertilizer that growers need to apply. The Utah Fertilizer Guide currently recommends an N credit to a rotational crop following …

Constraining Deformation Mechanisms Of Fault Damage Zones: A Case Study Of The Shallow San Andreas Fault At Elizabeth Lake, Southern California., Caroline Studnicky

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthquakes nucleate at depth and rupture along the fault plane up to the Earth’s surface releasing seismic energy as the fault propagates. This energy creates the shaking we feel on the surface. Some faults do not rupture and create shaking but deform slowly and smoothly accommodating fault slip over extended time periods. This process is referred to as aseismic slip or creep. Whether a fault ruptures or creeps depends on the properties of the rocks through which the fault plane extends. In order to model seismic hazards correctly, we need to characterize the composition, deformation structures, and alteration materials of …

Spatial And Temporal Patterns Of River Incision And Terrace Deposition In Response To Climate And Tectonics In Southern Taiwan, Dominique M. Shore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geologists often look at the Earth’s surface to understand the underlying processes that cause mountain formation. As tectonic forces drive uplift of Earth’s surface, processes of erosion transport sediment to lower elevations. Climate can play a large role in landscape formation as well as increased precipitation, accelerating rates of erosion. Rivers leave markers of landscape evolution through terrace landforms, former river floodplains that are left behind when rivers incise into a valley. To better understand landscape response to uplift, this research investigated the initial linkages between uplift, hillslope erosion (mass wasting) and river incision. At some point, it is thought …

The Biggest Snowball Fight In Earth History: Stratigraphy, Facies Analysis, And Geochronology Of The Pocatello Formation, Matthew W. Ellison

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Snowball Earth Hypothesis details a time in Earth’s history (the Cryogenian period) where the entire planet was encapsulated by kilometer thick ice sheets for two, multi-million-year glaciations. The first, known as the Sturtian, lasted from 717 – 660 million years ago while the second, known as the Marinoan, lasted form approximately 650 – 635 million years ago. Snowball Earth was caused by a few processes that sort of built upon each other: Rodinia began splitting apart ~740 million years ago which allowed for increased rates of silicate weathering. High rates of silicate weathering resulted in CO₂ drawdown which …

A Thermochronometric, Microtextural, And Numerical Modeling Approach To Deciphering The Rock Record Of Deformation Processes In The Wasatch And Denali Fault Zones, Robert G. Mcdermott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fault zones are the primary features that accommodate movement of Earth’s crust, resulting in the formation of mountain belts and damaging earthquakes. Rocks modified by faulting and brought to Earth’s surface by erosion are archives of the mechanical processes involved in earthquakes and(or) aseismic creep. Thermochronometry is a radioisotopic dating system primarily sensitive to temperature and offers a means to constrain dates and rates of thermal processes. Hematite is common in fault zones, amenable to (U-Th)/He (He) thermochronometry, and exhibits distinct microtextures diagnostic of fault zone mechanics. I apply hematite He thermochronometry and microtextural analyses with a suite of other …

Pre-Eruptive Evolution Of Izu-Bonin Boninite Melts: Mixing, Cooling, And Crystallization, Jesse L. Scholpp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Subduction is the geologic process in which one tectonic plate moves beneath another as it sinks into the Earth’s mantle. Subduction initiation in the Izu-Bonin Marianas system is the result of a gravitational failure during which one tectonic plate (the Pacific plate) spontaneously sinks beneath another (the Philippne Sea plate). Fluids released by the sinking plate that caused the overlying mantle to melt by reducing its meltimg temperature, forming the Izu-Bonin Mariana island arc system.

The resulting melts initially have the chemical compositions that are rich in silica and magnesia, and highly depleted in other elements, refered to a boninite …

Boron In The Pariette Wetlands, Uinta Basin, Ut, Palak Vasudeva

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Boron is a naturally occurring mineral in shale and coal beds formed in marine environments, as found in the Uinta Basin. Mining activity and the application of excess irrigation water on agricultural lands in the Pariette watershed lead to mobilization of B via surface run off. Water quality monitoring records from 2006- 2009 reported violations of Utah B standard for irrigation water 43-100% of the time, for water flowing through the Pariette Wetlands. This study aims to determine B distribution in abiotic (water, sediments) and biotic samples (macroinvertebrates, aquatic vegetation, fish, bird eggs), and to establish correlations between B concentrations …

Effect Of Plant Derived Tannins On Nitrogen And Carbon Cycling In Pasture Soils, Kathryn A. Slebodnik

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pasture-finished beef has become increasingly popular, but nitrogen losses from these pastures are of concern. Legumes containing condensed tannins such as birdsfoot trefoil (Lotus corniculatus) and sainfoin (Onobrychis viciifolia) may serve as environmentally and economically viable alternative forages in pasture finishing systems while reducing soil nitrogen loss. The goal of this project was to understand how tannin type and concentration affects soil nitrogen cycling both in the lab and the field. This thesis: 1) compared the physical, chemical, and biological characteristics of soil samples obtained from grazed grass and tannin and non-tannin containing legume pastures, 2) …

Nitrogen Fertilizer Needs Of First-Year Small Grains Following Alfalfa, Collin Pound

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat, barley, triticale, and oats, are small grains commonly grown as hay and grain following alfalfa in Utah and the Intermountain West, especially during drought years as they require less irrigation than corn. Several studies in many parts of the world have shown that first-year corn following alfalfa rarely needs nitrogen (N) fertilizer, yet relatively few have evaluated the N needs of small grains, especially small grains grown for hay. Objectives of this research were to determine whether N fertilizer is needed to economically optimize the yield and quality of first-year small grains following alfalfa, develop N guidelines, and whether …

Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Most streams in the southwestern United States do not flow all year, and given their delicate balance of sediment and water flow, they are sensitive to climate change. At the turn of the 20th century, many streams in the Southwest rapidly incised into their floodplains, forming arroyos with a channel entrenched into near-vertical channel banks mostly composed of sand and mud. This dissertation investigates past changes in watersheds draining the Grand Staircase region in southern Utah with the goal of understanding how changes in climate and sediment influence these types of streams. Results show sediment supply is highly variable across …

Greening-Induced Runoff Loss In The Western United States, Xueyan Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study assessed how vegetation will influence long-term runoff trends across the western United States (western US) in the future. I used a land surface model with improved dynamic vegetation root processes to better quantify regional runoff trends across five regions (Upper and Lower Colorado, Great Basin, Pacific Northwest, and California). The model was driven by statistically downscaled and bias-corrected outputs from three global climate models under the Representative Concentration Pathway 4.5 and 8.5 scenarios. Vegetation greening dominated significant transpiration increases that contributed most to increasing evapotranspiration across the western US, especially during spring and summer. Consistent with these trends, …

Connections Between Hydrothermal System Geochemistry And Microbiology: Traversing Tectonic Boundaries In The South-Central Peruvian Andes, Heather Upin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Geochemistry and microbiology are inherently tied in the natural world. The study of geomicrobiology has historically taken place in extreme systems, like hot springs of Yellowstone National Park and deep-sea hydrothermal vents, because the organisms that exist there have deep lineages on the tree of life and provide insight into early life on Earth. These microbes use chemical energy from nutrients available in their environment rather than relying on photosynthesis, energy obtained from the sun, to support their metabolism. The goal of this study is to improve our understanding of geological controls (for example the tectonic setting) on hot spring …

Soil Health Assessment On Arid Rangeland Soils Impacted By Oil And Gas Exploration, Development, And Extraction, Justin Allred

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Oil and gas well pad reclamation in arid environments such as in the Uinta Basin of Utah, presents unique challenges, including remote locations, limited water, and elevated soil salinity and sodicity. Successfully reclaimed Plugged and Abandoned (P&A) well pads should resemble the surrounding rangeland once fully reclaimed. Revegetation of native species is the primary indicator of successful reclamation, but the lack of water makes it challenging to re-seed native plants, while trying to prevent the encroachment of invasive plant species such as Bromus tectorum (cheatgrass), Salsola tragus (Russian thistle), and Halogeton glomeratus (halogeton). Could successful reclamation be reflective of good …

Nanotextural And Nanochemical Constraints On The Role Of Heat In The Development Of Crystalline-Hosted, Silica-Rich Fault Mirrors In The Wasatch Fault Damage Zone, Utah, Usa, Leah M. Houser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthquakes occur on faults, or rock that has experienced displacement at depth. Experimental work on a range of rock types reveals that >90% of earthquake energy on fault surfaces is given off as heat. Heat weakens rock and promotes earthquake rupture propagation. Thin (<0.5mm), high-gloss, "polished", light-reflective exposed fault surfaces are called fault mirrors (FMs). Fault mirrors may record rapid thermal, textural, and chemical changes that occur during an earthquake event.

The Wasatch Mountains are a N-S trending mountain range in Northern Utah that are the backdrop for Salt Lake City, Provo, Ogden, and Brigham City. This mountain range is currently built by the active Wasatch fault, and includes the exposed Wasatch fault damage zone. Many segments of the Wasatch fault are overdue for a potentially catastrophic …