Digital Commons Network^™

Sensitivity Of Present And Future Seasonal Precipitation Over Central United States To The Representation Of Rocky Mountain Topography, Ranasinghe Disanayakalage Sherly Shelton Ranathunga

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

Precipitation change across the Central United States (USA) is of great interest to the research community. Studies using global climate simulations suggest that the “100^th-Meridian”, which separates the “dry west” from the “moist east” will shift to the east as the climate responds to future emissions pathways. However, these simulations are run at relatively coarse resolutions, which do not accurately represent topography. Here, we perform regional simulations using the Weather Research and Forecasting (WRF) model to explore the sensitivity of present and future precipitation patterns across the central USA to the representation of the Rocky Mountains (RM). We …

Using Raman Spectroscopy To Validate Metamorphic P-T Paths From Western New Hampshire, Alexis Thomas

Boise State University Theses and Dissertations

Constructing and interpreting pressure-temperature (P-T) paths in metamorphic rocks is crucial to understanding tectonic processes occurring at mid- to deep-crustal levels. Conventional methods for obtaining P-T paths rely on mineral chemistry, such as chemical zoning in garnets, which assumes growth at chemical equilibrium. However, studies show that garnet growth can occur with disequilibrium nucleation, which can result in a biased or potentially incorrect P-T path. An alternative, physics-based approach using Raman spectroscopy can also be used to determine P-T paths. This method involves using elastic thermobarometry of quartz inclusions within garnet. In this study, I tested the hypothesis that P-T …

Diatom-Inferred Hydroclimate Variability In Marl Lake, Wi Over The Past ~2050 Years, Christian E. Sizemore

All-Inclusive List of Electronic Theses and Dissertations

Hydroclimate variability in the Midwest has increased over the past few decades, as as evidenced by increases in average precipitation and frequency of extreme hydroclimate events. Understanding natural climate variability in this region will help communities in the Midwest to better prepare and mitigate the risks associated with extreme hydroclimate variability in the future. Natural lakes in the Midwest are often effective archives of hydroclimate; many have been shown to respond directly to changes in climate both locally and regionally. We extracted a 4.5-meter sediment core, representing approximately 2050 years of sediment accumulation, from the deepest part of Marl Lake …

Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is considered amongst the most severe threats to terrestrial and aquatic ecosystems globally. Ecosystems in the southwestern United States have specifically been impacted by intense drought conditions since 2000. Higher temperatures combined with altered precipitation stresses many ecosystems; however, ecosystem specific responses to such stressors may vary. Here, the effects of climate change on semi-arid ecosystems are analyzed for some of the most vulnerable ecosystems in the southwestern United States: lacustrine, riparian, and dryland ecosystems.

Lakes and reservoirs in arid environments often serve as drinking water sources and recreational areas where high water quality is essential. Climate change …

Exploring Overbank Sediment Deposition Variation In Heavily Modified Floodplains Of The Lower Mississippi River: A Sedimentological And Geophysical Analysis, Seth Fradella

Master's Theses

Since the 1930s, the Lower Mississippi River (LMR) has experienced large-scale modifications to the channel profile and surrounding floodplains through dams, dikes, revetments, dredging, and channel cutoffs. Although these changes have improved navigation and reduced flood risk, unanticipated changes to the major flood return period, individual flood severity and duration, and sediment regime have become increasingly apparent and sometimes problematic, such as the 2011 and 2018-2020 floods. Flood control levees along the LMR have reduced the natural floodplain area by 70-90%, resulting in heavily restricted overbank storage capacity of water and sediment. For the same flood events in recent history, …

Tales In The Teeth: Using Isotopic Analysis To Understand The Paleoecology And Social Behavior Of Brontotheres Of The Intermountain Basins During The Middle Eocene, John Michael Michalski

All Graduate Reports and Creative Projects, Fall 2023 to Present

Isotopic analysis has been a common practice used in paleontology to study ancient ecosystems, and the lives of animals therein. Oxygen isotopic analysis is of particular importance not only because of its use in studying paleoecology, diet, and migration, but also its use in studying mountain elevation, and its impact on ancient ecosystems. I use stable oxygen isotopic analysis to study the habits and ecology of brontotheres from intermountain basins surrounding the Uinta Mountains of Utah and Wyoming, USA. I studied the oxygen isotopes from 16 fossil specimens of teeth, most of which belonged to brontotheres, including the genera Palaeosyops …

Staying Fresh: Unconventional Approaches Towards Advancing Energy Sustainability, Water Resources, And Community Resiliency In The Southwestern United States, Judith Hoyt

Open Access Theses & Dissertations

This dissertation addresses critical challenges in urban heat management, sustainable energy resource utilization, and water quality communication through three studies. Study 1 investigates the impact of roof color on urban heat islands in Tucson, Arizona where approximately 70% of roofs display high albedo (i.e., light) colors. Energy consumption simulations conducted indicate that converting dark- to light-colored roofs could save Tucson approximately $1,400,000 annually in energy costs, highlighting the potential of cool roofs for energy savings and improved thermal comfort. Study 2 assesses the sources of lithium in subsurface waters in West Texas and South Central New Mexico. Water chemistry data …

Upscaling Sapflow Measurements To Footprint Transpiration Estimations In The Jornada Experimental Range, New Mexico, Usa, Habibur R. Howlider

Open Access Theses & Dissertations

This study proposes a new method for computing transpiration across an eddy covariance footprint using field observations of plant sap flow, phytomorphology sampling, uncrewed aerial system (UAS) digital image processing, and eddy covariance micrometeorological measurements. The method is applied to the Jornada Experimental Range, New Mexico where we address three key questions: (1) How do daily summer transpiration rates of Mesquite (Prosopis glandulosa) and Creosote (Larrea tridentate) individuals of different ages compare? (2) How can the contributions of plants of varying sizes and ages be integrated for terrain-wide transpiration estimates? (3) What is the contribution of transpiration to total evapotranspiration …

Investigating Styles Of Contraction And Overprinting By Rio Grande Rift Extension In The Southern Indio Mountains, Western Texas, David W. West

Open Access Theses & Dissertations

Laramide-style intracontinental deformation occurred throughout a large area in the western United States from the late Cretaceous through the Eocene. This event is largely investigated and viewed from classic exposures in Colorado and Wyoming, extending south to southern New Mexico. In this region the Laramide orogen merges with the Mexican fold and thrust belt (MFTB) and the northern limits of the Mexican orogen along a blurry boundary. In the Indio Mountain range in western Texas, Cretaceous sediments were deposited in the Jurassic-Cretaceous Chihuahua trough. They were inverted due to contraction and emplaced adjacent to the Diablo Plateau. This region lies …

New Insights Into The Diverse Intraplate Volcanism Present Within The Howland And Baker Island United States Exclusive Economic Zone, Nicholas Foresta

UNLV Theses, Dissertations, Professional Papers, and Capstones

The origin of oceanic volcanism has been attributed to various mechanisms, such as upwelling mantle plumes, lithospheric extension driven decompression melting, and small-scale convective cells in the asthenosphere. Discovering the range of magmatic drivers present in the ocean basins aids in understanding mantle geodynamics and tectonic processes. A recent seafloor exploration campaign within the Howland and Baker Island (HBI) U.S. Exclusive Economic Zone (EEZ; approximately near the equator and the International Date Line) resulted in the collection of multiple lava flow samples, which offer valuable insights into the complex origins and dynamics of intraplate seamounts. According to current absolute plate …

Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Ecological disruption events such as mass extinctions can result in the permanent alteration in clades and ecosystems. A pivotal time of change during the history of life on Earth can be seen in the Devonian Period. During this time, major transitions in marine and terrestrial system resulted in a different world at the end of the period in comparison to the beginning. One such group most heavily impacted were trilobites. Trilobites were reduced to one order by the end of the Devonian: Proetida. My dissertation focuses on phylogenetic, biogeographic, and paleocommunity patterns of this group, known as the last of …

Hydrogen Stable Isotope Constraints On Hydration Of Colorado Plateau Lower Crust From Oligocene-Miocene Navajo Volcanic Field Xenoliths, Shelby Dianne Litton

All Graduate Theses and Dissertations, Fall 2023 to Present

Understanding flat-slab subduction is crucial as it involves the horizontal movement of an oceanic plate beneath a continental margin over a long distance. This tectonic process is widespread yet not fully understood, particularly regarding how it influences the chemical makeup of the continental plate and recycling in the hydrosphere. By analyzing isotopes, which are variations of certain elements found in minerals and water, we can gain insights into the sources of chemicals and geological processes at play. Our study area included six locations within the Navajo volcanic field (NVF), a region in the Colorado Plateau. We analyzed 23 lower crustal …

Shedding Light On Past Ice-Free Intervals In Northwest Greenland: Luminescence Dating Of The Base Of The Camp Century Ice Core, Hawke Woznick

All Graduate Theses and Dissertations, Fall 2023 to Present

The goal of this thesis is to provide greater resolution on the age and character of the subglacial sediment recovered from the base of the Camp Century ice core, northwestern Greenland. Geochemical analysis indicated that the upper sub-ice sediments were geochemically different and experienced greater weathering than the basal unit underlying a one-meter silty ice lens. Analysis of feldspars within the very fine sand fraction indicates they are dominated by potassium feldspar. Sediment was dated using luminescence, which provides an age for the last time sediment was exposed to light. Luminescence analysis returned ages around 420 thousand years old, which …

Dynamics Of Climate And Tectonics On Surface Processes And Their Sedimentary Archives In The Colorado Plateau And Basin And Range, Usa And The Calabrian Forearc, Sicily, Natalie M. Tanski

All Graduate Theses and Dissertations, Fall 2023 to Present

Landscapes change over time in response to movements of the Earth’s crust and the effects of climate. This dissertation examines how these factors shape different landscapes, focusing on erosion of river canyons in elevated plateaus, how the transport history in quartz sand may be encoded in its properties, and how a paleo-delta has formed in response to sea-level change and fault displacement. I use dating techniques, field methods, and topographic analyses to offer insight into erosional patterns and rates in different landscapes.

Rivers can take a long time to adjust to changes in boundary conditions, even after those changes have …

Silica Fault Mirror Development Along The Cordillera Blanca Detachment Fault, Peru, Kayla Michelle Chaudoir

All Graduate Theses and Dissertations, Fall 2023 to Present

Earthquakes occur along planes of geologic weakness called faults. Thin, light-reflective surfaces on faults are called fault mirrors and often considered signatures of previous earthquakes along these faults. The Cordillera Blanca mountain range in the Peruvian Andes provides a natural laboratory to explore meter scale exposures of fault mirrors. Three naturally formed fault mirror samples were collected from the Cordillera Blanca detachment fault which runs along the edge of the Cordillera Blanca mountain range. Prior work on this fault reveals that it is capable of destructive earthquakes every few thousand years and is a significant earthquake hazard to the surrounding …

Shaking Off The Rust: Unraveling The Depositional And Diagenetic History Of Enigmatic Ferroan Dolostones In The Cambrian Bright Angel Formation, Tonto Group, Grand Canyon, Joseph J. Clevenger

All Graduate Theses and Dissertations, Fall 2023 to Present

Within the siliciclastic-sediment-dominated Bright Angel Formation (BAF) of the iconic Cambrian sedimentary strata (Tonto Group) in Grand Canyon National Park, Arizona, workers have identified and named prominent reddish-brown cliffs breaking up the generally slope-forming unit near, but separated from, its upper contact with the limestone-dominated Muav Formation, the "Rusty Brown Dolostones" (RBDs). Previous hypotheses suggest that the RBDs are chemically and physically altered tongues of the Muav Formation intercalated with the BAF at increasingly higher stratigraphic positions from west to east within the Canyon. A genetic association between the Muav Formation and the RBDs, as well as between the RBDs …

Accretion Of Warm Chondrules In Weakly Metamorphosed Ordinary Chondrites And Their Subsequent Reprocessing, Alex M. Ruzicka, Richard C. Hugo, Jon M. Friedrich, Michael T. Ream

Geology Faculty Publications and Presentations

To better understand chondrite accretion and subsequent processes, the textures, crystallography, deformation, and compositions of some chondrite constituents in ten lithologies of different cluster texture strength were studied in seven weakly metamorphosed (Type 3) and variably shocked ordinary chondrites (Ragland—LL3 S1, Tieschitz—H/L3 S1, NWA 5421—LL3 S2, NWA 5205—LL3 S2, NWA 11905—LL3-5 S3, NWA 5781—LL3 S3, NWA 11351—LL3-6 S4) using optical and electron microscopy and microtomography techniques.

Results support a four-stage model for chondrite formation. This includes 1) limited annealing following collisions during chondrule crystallization and rapid cooling in space prior to accretion, as evidenced by olivine microstructures consistent with dislocation …

Differential River Incision Due To Quaternary Faulting On The Río Jemez-Salado System At The Million-Year Timescale, Cameron Reed

Earth and Planetary Sciences ETDs

Analysis of long-term average bedrock incision rates along the Río Salado-Jemez system using fluvial terraces can be used to test and quantify the hypothesis that differential river incision reflects Quaternary fault slip during ongoing uplift of the Jemez and Nacimiento Mountains. Terrace flights were correlated from the Arroyo Peñasco to the Río Salado near the southern nose of the Nacimiento and along the Río Jemez. Using highest/oldest river terraces, resulting bedrock incision values average out glacial/interglacial cycles and are interpreted to reflect differential uplift. For previously mapped and correlated terraces, we applied lidar datasets to refine strath heights. We also …

Constraining The Evolutionary Stages Of A Hypogene Karst System By Combining Morphological, Geochemical And Geochronological Data - The Example Of Carbonate Breccia-Hosted Melnička Peštera, Marjan Temovski, Zsófia Ruszkiczay-Rüdiger, Kata Molnár, László Rinyu, Alexander Wieser, Oscar Marchhart, László Palcsu

International Journal of Speleology

A combination of morphological observations, geochemical data from calcite minerals and geochronology by burial age dating and U-series is used to constrain the geological and geomorphological setting and the evolutionary stages of a hypogene karst system. This methodological suit is applied to Melnička Peštera, a horizontal cave developed in carbonate breccia overlying dolomite marble in Melnica locality (N. Macedonia), where hydrothermal karst development occurred in both dolomite and calcite marble. The passage morphology of the cave, having a reverse triangle, Laughöhle cross-sections, suggests development near the water table by slowly moving waters. Calcite crusts are found throughout the cave, and …

Proterozoic Tectonic Evolution Of The Lower Granite Gorge, Grand Canyon, Arizona: A Middle Crustal Record Of Multiple Orogenic Pulses, John M. Bailey

Earth and Planetary Sciences ETDs

The well-exposed basement transect in the Lower Granite Gorge (LGG) of western Grand Canyon provides a middle-crustal record of suturing crustal blocks during the Proterozoic accretionary history of southwestern Laurentia. Orogenic evolution included at least three stages: (1) subduction-related ~1.75-1.72 Ga volcanic arc magmatism, turbidite deposition, and suturing of arc terranes with different crustal thicknesses; (2) intense northwest-southeast crustal shortening at ca. 1.71-1.68 Ga to form the Vishnu Mountains during the Yavapai orogeny; (3) dextral strike-slip shear zones development at ~1.4 Ga during long-term crustal residence and slow cooling above ~250 °C (~10 km) until ~1.3 Ga. Final cooling from …

Chemical And Morphological Characterization Of Airborne Particulate Matter At The Jackpile-Paguate Mine, Pueblo Of Laguna, New Mexico: Implications For Potential Metals Exposure, Andreanna C. Roros

Earth and Planetary Sciences ETDs

The inhalation of windblown particulate matter (PM) derived from abandoned uranium mines (AUMs) is a potential environmental health risk to Native American communities that live in proximity to these sites. However, the aeolian transport of metal-bearing PM from AUMs, as a potential exposure pathway, has not been investigated in any detail. In this study, we sampled airborne particulate matter within the Jackpile Mine located on the lands of the Pueblo of Laguna, New Mexico using passive sampling methods to understand the characteristics of dust within the mine site. The objective was to determine the elemental concentrations, mineralogy, and morphology of …

Sulfur Sequestration In Anhydrite Through Alteration Of Calcic Wall Rock, Lexi Kenis

Earth and Planetary Sciences ETDs

Heterogeneous gas-solid reactions are suggested as a potential mecha-
nism for sequestering gaseous sulfur through the alteration of calcic wall
rocks. This study explores the concept of a “hierarchy of reactions” pro-
posed by Giggenbach (1987), outlining the interplay between gas components
and redox-related minerals in volcanic wall rocks. Mt. Pinatubo provides a
more felsic composition and more oxidizing conditions compared to previ-
ously studied volcanoes, Kudryavy and Erta Ale (Henley and Fischer, 2021),
and Lascar a more oxidizing case with a similar composition. By employing
thermodynamic models and synthetic melt experiments, evaluations of effi-
ciency of sulfur sequestration across …

Carbonate And Organic Proxies And The Impacts Of Climate On Lake Systems: Paleoclimate Interpretations From Lake Chalco, Mexico, Aria Holmes

Earth and Planetary Sciences ETDs

This project incorporates several lines of evidence to better understand the climate at Lake Chalco. Chapter 1 utilizes oxygen isotopes from carbonates and show that the Inter Tropical Convergence Zone varies on primarily glacial and millennial timescales; precession is not observed. These data indicate glacials periods were shallower and interglacials were wetter periods at Lake Chalco. Chapter 2 studies carbon, nitrogen, C/N, and TOC proxies and finds that the lake conditions during the glacials and interglacials are primarily a mixed algal-macrophyte-terrestrial organic matter. Deviations show that the lake during the interglacials had more algal organic matter- reflecting influxes of nutrients …

Sand, Ice, And X-Rays: Developing Xct Methods For Frozen Samples And Refining Siliciclastic Facies Models For Perennially Ice-Covered Lakes, Utilizing Cores From Lake Fryxell, Mcmurdo Dry Valleys, Antarctica, Holly M. Levett

Earth and Planetary Sciences ETDs

Sedimentation in perennially ice-covered lakes (PICLs) is proposed to be bi-modal, with mud deposited by stream inflow and sand deposited on the ice cover by aeolian processes and then melting through by absorption of solar radiation. Here, we consider Lake Fryxell, a PICL in the McMurdo Dry Valleys, and several lake bed cores about 30 cm in length, to better understand PICL facies through time, using micro X-ray CT (XCT). Using XCT images along with sieve and laser granulometry data, we constrained the grain-size of PICL deposits to dominantly medium / fine sand with a coarse component. The presence of …

Chemical And Physical Properties Of Fine Fractions From A Village Proximate To A Uranium Mine: Insights About Soil Health, Mary P. Haley

Nanoscience and Microsystems ETDs

Thousands of abandoned uranium mines (AUM) in Native American tribal lands have not been fully remediated, leaving uranium mine wastes exposed and accessible for potential erosion and transport by wind. Analyzing the metal and organic content of the fine-grained fractions in soils could uncover the impact of mine legacy on the soil health in communities that live in proximity to AUM. This study investigates the physical and chemical properties of the fine-grained fraction (μm) of soils to quantify the effect of heavy metal-bearing particulates on the soil health in the village of Paguate and within the Jackpile-Paguate AUM located on …

Historical Structural Analysis Of The Rileyville Quadrangle, Page County, Virginia, Sydney Fergen

2024 Symposium

The Northwest corner of Virginia, within the Appalachian Mountains, formed during a collision of continents called the Alleghenian Orogeny roughly 250 million years ago(Ma). This event caused tectonic plates to collide, reforming the fractured continental crust back into a new supercontinent, Pangaea. This process took over 100 Ma and closed the Rheic Ocean. These large-scale compressional tectonics had several effects including formation of the Allegheny Plateau and Taconic Mountain range, which has gradually eroded exposing a series of plunging folds and imbricated thrust faults. This poster presents a structural analysis of the Rileyville quadrangle to help decipher regional geologic history …

U/Pb Zircon Ages Of Saltese Upland Conservation Area, Priest River Core Complex, Jessica M. Lawrence, Natalie Potter, Chad Pritchard

2024 Symposium

The Saltese Upland Conservation Area provides a window into the Priest River Core Complex with Lake Hauser gneiss grading to migmatite, garnet-baring amphibolite juxtaposed with felsite to orthogneiss rocks. U/Pb ages from LA-ICP-MS of separated zircon grains show trends very similar to detrital 207Pb/206Pb ages of the Belt Supergroup. The amphibolite displays a much stronger peak at 1.4 to 1.5 Ga , possibly related to the emplacement of Mesoproterozoic dikes. The amphibolite and granitic rocks also contain a number of grains with 238U/206Pb around 60 Ma preserving events from the uplift of the Priest River Complex in the Spokane area. …

Paleohydraulic Analysis Of Megaripples From Outburst Floods In Omak, Washington, Jessica M. Lawrence

2024 Symposium

Located in Omak, Washington atop what is observed to be a gravel point bar are giant current ripples associated with outburst floods that took place during the Pleistocene (O’Connor et al. 2020 and Minard 1985). Thorough breakdown of these giant current ripples was conducted using their geomorphologies associated with stream flow mechanisms for gravel bedforms such as hydraulic radius of cross- sectional area and velocity using Manning’s equation to determine Froude’s Number (USDA 2007). Ripple index associated with ripple wavelength and height was then compared to additional megaripples located throughout Scablands of Washington that have been correlated to the Great …

Preliminary Analysis Of Per-And Polyfluoroalkyl Substances (Pfas) In Surface Waters Of The West Plains Region Of Spokane County, Jerusha Hampson

2024 Symposium

Per-and Polyfluoroalkyl Substances (PFAS) have become a national issue as regulatory limits for these toxins have just recently been put into the Clean Water Act. The West Plains has been significantly impacted by PFAS contamination due to the decades-long use of aqueous film-forming foam (AFFF) for firefighting training at both Fairchild Airforce Base and the Spokane International Airport. Though research is still underway, it is known that PFAS contamination in West Plains groundwater is significant and widespread. This study focuses on West Plains surface waters, as there is currently less information about how these water bodies are impacted by PFAS. …

Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles., K J Walsh, R-L Ballouz, W F Bottke, C Avdellidou, Harold Connolly Jr., M Delbo, D N Dellagiustina, E R Jawin, T Mccoy, P Michel, T Morota, M C Nolan, S R Schwartz, S Sugita, D S Lauretta

School of Earth & Environment Departmental Research

Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but …