Geology Commons^™

The Role Of Heterogeneity In Earthquake Rupture Dynamics: Insights From Friction Experiments On A 1-Meter Laboratory Fault, Alejandro Aguilar

All Graduate Theses and Dissertations, Fall 2023 to Present

Tectonic faults are made of many kinds of rocks and minerals, creating natural weak and strong zones along faults where earthquakes occur. These differences can affect how faults move, including whether slip occurs slowly and quietly or suddenly and destructively during an earthquake. However, it is not fully understood how these variations influence when earthquakes start, how fast they spread, and whether they stop or grow into large ruptures. This research studies how different fault materials interact during earthquake slip. Using a large laboratory machine that simulates fault movement under realistic conditions, we recreate earthquake processes and closely measure how …

Leveraging The Iron Oxide Archive Of Mineralization, Deformation, And Exhumation Across Geologic Time, Jordan L. Jensen

All Graduate Theses and Dissertations, Fall 2023 to Present

The iron oxide mineral hematite commonly forms from groundwater near Earth’s surface and can preserve a history of fluid flow, fault slip, and landscape evolution. This record can be decoded using (U-Th)/He thermochronology, a dating method based on the temperature-sensitive ingrowth of helium from uranium and thorium decay. Because later heating and natural variation in hematite crystals can produce ambiguous (U-Th)/He results, I integrate dating with tools that reveal differences in hematite chemistry and textures. I apply these techniques to two distinct settings: ancient granitic rocks in Colorado and an active fault zone in the southern San Andreas fault (SSAF) …

Fault Structure, Deformation Mechanisms, And Why Fault Zones Matter To Society, Elizabeth S. Petrie, David A. Ferrill, Kelly K. Bradbury, James P. Evans

Geosciences Faculty Publications

Faults are widespread geologic structures that form in sediment and all rock types, occur in all tectonic regimes, and can be a blessing or a curse to society. Faults and fault zones act as conduits for underground movement of water and as plumbing systems for aquifers and springs essential for human habitation in many semi-arid and arid regions worldwide. Faults also provide pathways for natural oil and gas migration and high-permeability zones in hydrocarbon reservoirs, as well as barriers contributing to trapping and reservoir compartmentalization. By enhancing permeability in many geothermal energy systems, faults can be essential for fluid circulation …

Collaborative Research: Rapid: Fault Rupture And Spring Sampling Of The 2023 Kahramanmaras, Turkey, Earthquake Sequence Ruptures, Alexis Ault, Dennis Lowell Newell

Funded Research Records

No abstract provided.

Collaborative Research: Evolution Of The Tristan-Gough-Walvis Ridge Hotspot System: Age And Composition Of Expedition 391/397t Volcanic Basement, Katherine Elizabeth Potter

Funded Research Records

No abstract provided.

The Depositional Environment Of The Triassic Cow Branch Formation, Dan River Basin Of Virginia And North Carolina Through Petrographic Study And Geochemical Analysis, And In Relation To Taphonomic Processes And Vertebrate Morphology, Gina M. Workman

All Graduate Reports and Creative Projects, Fall 2023 to Present

The Upper Triassic Cow Branch Formation of the Dan River Basin, located in southern Virginia and northern North Carolina, has long captivated generations of geoscientists. Since the 1970s, researchers have sought to unravel the mystery surrounding the depositional environment of this ancient lake system. This world-class lagerstätte hosts a diverse assemblage of fossil fauna and flora, with a notable preservation bias toward fossil vertebrates, most prominently the archosauromorph, Tanytrachelos ahynis. The geology of the Cow Branch strata continues to evoke a persistent question: Are these sediments representative of a shallow or deep lake?

I undertook a petrographic and geochemical study …

Using Luminescence Of Quartz Temper From Archaeological Pottery To Infer Wildfire Intensity In The Southwestern Us, Brooklyn D. Dib

All Graduate Theses and Dissertations, Fall 2023 to Present

The size and frequency of wildfires have increased recently, impacting ecosystems, communities, and human health. This research uses the heat-sensitive luminescence signals of quartz sand temper within archaeological pottery to record past wildfire conditions. Pottery sherds, which are fragments of archaeological pottery, from the forest floor in sites in New Mexico and Arizona were collected from different fire contexts (no fire exposure, historical fires, prescribed burns, and modern wildfires). These forests are primarily Ponderosa Pine with a grassy understory. The interior sand grains of each sherd sample were analyzed using optically stimulated luminescence, which dates when the mineral grains were …

An Integrated Lithospheric Geotherm Model From Seismic Data And Plate Ages, Amanda R. Leaman

All Graduate Theses and Dissertations, Fall 2023 to Present

This research aims to develop advanced methods to accurately depict temperature profiles within the lithosphere, the Earth’s rigid outer layer. These temperature profiles extend from Earth’s surface to the asthenosphere, the ductile layer below the lithosphere. Constraining the poorly-known temperature distribution within the upper Earth is important for modeling the deformation of Earth’s crust over varying timescales and is essential for advancing realistic simulations of Earth dynamics. Here, I utilize enhanced global seismic data, coupled with recent advances in our understanding of mineral systems, to create several global lithospheric models in which I estimate temperature profiles from seismically observable features …

Dream Pilot Project: Analysis Of Groundwater Development At Six Villages In Ethiopia, Lindsay K. Gordon

All Graduate Reports and Creative Projects, Fall 2023 to Present

This study presents a hydrogeologic assessment of the Distributed Renewable Energy Agriculture Modalities (DREAM) pilot project, an ongoing groundwater development initiative in rural Ethiopia. This project integrates solar-powered groundwater infrastructure across six villages to improve water access, agricultural productivity, and economic stability.

Fourteen production wells were installed at Murche, four at Dalle, and additional test wells at Murche, Dalle, Chefe Kora, and Huluku. Transmissivity values and the number of wells at Murche suggest that local water needs are currently being met. In contrast, fewer wells were drilled at Dalle. This reflects the high cost of well construction relative to yield, …

Geochemical And Stratigraphic Characterization Of The Morrison Formation And Cedar Mountain Formation Contact In The Island Park Quadrangle, Uintah County, Utah, Emily Mcdermott

All Graduate Theses and Dissertations, Fall 2023 to Present

The Upper Jurassic Morrison Formation and Lower Cretaceous Cedar Mountain Formation are among the richest sources of dinosaur fossils. Despite a 24-million-year gap in time (the Jurassic–Cretaceous unconformity), these formations are difficult to distinguish due to their similar rock types and colors. In Utah's Island Park quadrangle (IPQ), these formations are not separated on existing geological maps. This study focuses on identifying and understanding the formational boundary between them using field observations, stable isotope analysis, clay mineralogy, and chemical techniques such as X-ray diffraction (XRD) and X-ray fluorescence (XRF).

Unlike other areas where a conglomerate layer marks the boundary, the …

Role Of Quartz Grain Size And Saturation On Fault Strength And Frictional Healing, Sapana Regmi

All Graduate Theses and Dissertations, Fall 2023 to Present

Rocks near the Earth's surface (less than 5 kilometers deep) often break and grind against one another to create crushed rock materials known as fault gouge. These fault gouges are filled with fragmented particles and broken rocks, which vary in grain size over time and space due to repeated earthquakes. This variation in grain size distribution along fault gouge can affect the strength of the fault, how it slips during an earthquake and how it 'heals' or recovers strength between earthquakes. Further, fault gouges often contain water from underground sources, which can influence how they slip. Previous studies have examined …

Evaluating Uplift At The Leading Edge Of The Yellowstone Hotspot - A Study Of The Shoshone River Drainage, Emma Tombaugh

All Graduate Theses and Dissertations, Fall 2023 to Present

The stationary mantle plume (or hotspot) underlying the Yellowstone region has caused parts of the surrounding landscape to rise as the continental plate migrates over it. However, scientists do not fully agree on the spatial pattern of this uplift and few measurements of the landscape have been made to provide estimates of uplift rates. To better understand uplift patterns and rates, this study examines the Shoshone River, which flows across the predicted zone of highest uplift at the northeastern, leading edge of the hotspot. Digital-terrain analysis is used to measure channel steepness and field and imagery approaches are used to …

Reevaluating The Drumian Carbon Isotope Excursion (Dice) In Western-Central Utah, Michelle M. Norman

Undergraduate Honors Capstone Projects

The Drumian Stage of the Cambrian Period is defined by the First Appearance Datum (FAD) of the cosmopolitan trilobite Ptychagnostus atavus in 504.5 Ma strata deposited on the slope and shelf of the Laurentia margin. The Drumian Global Stratotype Section and Point (GSSP), showing the best preserved example of P. atavus compared to global outcrops, is defined in the Drum Mountains of west-central Utah. Due to the inconsistent nature of fossil preservation, researchers have sought secondary proxies to identify Drumian-aged strata in the absence of age-diagnostic fauna. One key proxy is the Drumian Carbon Isotope Excursion (DICE), an ~-2.5‰ carbon …

Inconsistencies With The Drumian Carbon Isotope Excursion (Dice) In West-Central Utah, Michelle Norman

Student Research Symposium

Geologic Setting

• During the Cambrian Period (539-485.4Ma), the western US was submerged by a shallow ocean
• Carbon cycle fluctuations in stable carbon were preserved in marine sediments
• One such period of geologic time, the Drumian Age (500Ma), is defined by the first appearance of a deepwater trilobite, P. atavus, in west-central Utah
• Researchers have hypothesized we can find Drumian-aged rocks without the fossils using carbon cycle fluctuations preserved in limestone
• the Drumian Carbon Isotope Excursion (DICE) is defined as a -2.5‰ fluctuation in global carbon-bearing rocks

Earth Orbital Rhythms Links Timing Of Deccan Trap Volcanism Phases And Global Climate Change, Thomas Westerhold, Edoardo Dallanave, Donald Penman, Blair Schoene, Ursula Röhl, Nikolaus Gussone, Junichiro Kuroda

Geosciences Faculty Publications

At the end of the Cretaceous, the massive Deccan trap (DT) volcanic eruptions are regarded as the primary driver of global climate deterioration. Accurate age models are key to unravel the sequence of events related to DT volcanism onset and effects on the global climate system. We establish a direct geochemical link between DT volcanism as recorded in marine osmium isotopic data and global climate change documented in benthic foraminifera carbon and oxygen isotope records. Based on our state-of-the-art astronomically calibrated age model, two major shifts in marine ¹⁸⁷Os/¹⁸⁸Os at 66.49 and 66.28 million years ago are …

Karst Hydrologic Memory Supplements Streamflow During Dry Periods In Snow-Dominated, Mountainous Watersheds, Hyrum Tennant, Bethany T. Neilson, Devon Hill, Dennis L. Newell, James P. Evans, Seohye Choi, James P. Mcnamara, Nathaniel Ashmead, Tianfang Xu

Geosciences Faculty Publications

Analysis of PRISM and SNOTEL station data paired with USGS streamflow gage data in the western United States shows that, in snow-dominated mountainous watersheds, streamflow regimes differ between watersheds with karst geology and their non-karst neighbours. These carbonate aquifers exhibit a spectrum of flow paths encompassing karst conduits, including large fractures or voids that transmit water readily to springs and other surface waters, and matrix flow paths through soils, highly fractured bedrock, or porous media bedrock grains. A well-connected karst aquifer will discharge a large portion of its accumulated precipitation to surface water via springs and other groundwater flow paths …

Creating Place-Based Introductory Geoscience Field Trip Curricula For Indigenous Students, Kitri Spencer

All Graduate Reports and Creative Projects, Fall 2023 to Present

This project seeks to produce and evaluate a place-based geoscience field trip curriculum along the San Juan River designed for Indigenous students. The Geoscience on the San Juan River field trip uses a “place-based” approach to weave scientific concepts with the cultural knowledge and lived experiences of the students. Learning activities were designed to accommodate a wide range of learning preferences and accessibility needs with the hope of increasing Indigenous enrollment in the geosciences. The lesson plan was tested on June 4^th, 2022 during a guided rafting excursion on the San Juan River for students participating in the …

Testing For Patterns Of Deformation From The Yellowstone Hotspot Along The Gallatin River, Sw Montana, Jack Willard

All Graduate Theses and Dissertations, Fall 2023 to Present

Yellowstone has fascinated humans for thousands of years. Geologists have addressed many of the region’s mysteries, including the underlying mantle hotspot, the chain of calderas tracking the motion of the North American Plate over this hotspot, and the risks posed by the super volcano. However, the way that the hotspot impacts regional tectonics and topography remains under-studied. Influential previous work recognized the Yellowstone Crescent of High Terrain (YCHT), an arc of high topography around the Yellowstone Plateau with limbs extending to the west and south into central Idaho and northern Utah. The YCHT is also hypothesized to be the pattern …

Using Luminescence Dating To Investigate Geomorphic And Archaeologic Features At The Wiggins Fork Bison Jump Complex, Northwestern Wyoming, Emma T. Krolczyk

All Graduate Theses and Dissertations, Fall 2023 to Present

The Wiggins Fork Bison Jump Complex, located in northwestern Wyoming, is comprised of thousands of human-placed rock piles, known as cairns, that were placed within lines to form an extensive network of drivelines and funnels leading to cliffs or steep slopes. These archaeological features were used by Native Americans as a bison hunting method, where the animals were driven off cliffs for harvest. This research uses luminescence dating, which determines when sediment was last exposed to sunlight, to date the timing of driveline construction and the deposition ages of the underlying river deposits.

Research focused on Jump #4, which had …

Signatures Of Fluid-Rock Interactions In Shallow Parts Of The San Andreas And San Gabriel Faults, Southern California, James P. Evans, Kaitlyn Crouch, Caroline Studnicky, Sharon Bone, Nicholas Edwards, Samuel M. Webb

Geosciences Faculty Publications

We examine deformed crystalline bedrock in the upper parts of the active San Andreas and ancient San Gabriel Faults, southern California, to 1) determine the nature and origin of micro-scale composition and geochemistry of fault-related rocks, 2) constrain the extent of fluid-rock interactions, and 3) determine the interactions between alteration, mineralization, and deformation. We used drill cores from a 470 m long inclined borehole through the steep-dipping San Gabriel Fault and from seven inclined northeast-plunging boreholes across the San Andreas Fault zone to 150 m deep to show that narrow fault cores 10 cm to 5 m wide lie within …

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 …

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 …

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 …

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 …

Sensitivity Of Ocean Circulation To Warming During The Early Eocene Greenhouse, Sandra Kirtland Turner, Andy Ridgwell, Allison L. Keller, Maximilian Vahlenkamp, Adam K. Aleksinski, Philip F. Sexton, Donald E. Penman, Pincelli M. Hull, Richard D. Norris

Geosciences Faculty Publications

Multiple abrupt warming events ("hyperthermals") punctuated the Early Eocene and were associated with deep-sea temperature increases of 2 to 4 °C, seafloor carbonate dissolution, and negative carbon isotope (δ¹³C) excursions. Whether hyperthermals were associated with changes in the global ocean overturning circulation is important for understanding their driving mechanisms and feedbacks and for gaining insight into the circulation's sensitivity to climatic warming. Here, we present high-resolution benthic foraminiferal stable isotope records (δ¹³C and δ¹⁸O) throughout the Early Eocene Climate Optimum (~53.26 to 49.14 Ma) from the deep equatorial and North Atlantic. Combined with existing …

Magmatic Conditions Aiding Synconvergent Extension Above The Peruvian Flat Slab, Tyler A. Grambling, Micah J. Jessup, Dennis L. Newell, Nadine L. Grambling, Coleman D. Hiett

Geosciences Faculty Publications

The Cordillera Blanca and Cordillera Huayhuash contain some of the highest topography in the Andes and provide insight into tectonomagmatic processes associated with the onset of flat-slab subduction. These adjacent ranges shared a similar history of deformation and exhumation prior to the late Miocene, when synconvergent extension began in the Cordillera Blanca. Magmatism in the Cordillera Huayhuash has been inferred as coeval with magmatism in the Cordillera Blanca. Yet, extension, which has been correlated with magmatic heat flow, is limited to the Cordillera Blanca. New zircon U-Pb dates and trace and rare earth element concentrations from the Cordillera Blanca batholith …

Characterization Of Carbonaceous Fault Rocks, Pioneer Fault Zone, South-Central Idaho, Genna Baldassarre

All Graduate Reports and Creative Projects, Fall 2023 to Present

Differing crystallinities of carbonaceous material are common in fault rocks across a range of geologic settings and spatial scales and may provide constraints on strain rate, the nature of fault slip, fluid-rock interactions, and temperature variations over the earthquake cycle. The Pioneer fault at Little Fall Creek in south-central Idaho provides an excellent opportunity to study nanostructure changes of carbonaceous matter as a function of fault deformation. At this location, the Pioneer Fault exhibits a well-defined principal slip zone (PSZ) composed of multi-layered white siliceous mineralization and black carbon to graphite with a continuously exposed adjacent damage zone that includes …

Building And Using A Hydrology Experiment For Place-Based Learning With Native American Students, Michaela Shallue

All Graduate Theses and Dissertations, Fall 2023 to Present

Geoscience has a known diversity problem, specifically a participation gap of ethnic minority representation, and it is especially severe regarding Native American representation. To address this participation gap, an identity gap needs to be addressed first. Native students need to visualize themselves as geoscientists before they can commit to geoscience programs and careers. This project uses a hands-on, place-based learning activity as an opportunity for Native students to better see themselves as geoscientists.

A portable rainfall simulator was constructed, calibrated, and refined for use in teaching concepts about rainfall, runoff, and erosion. It was employed in place-based learning exercises with …