Physical Sciences and Mathematics Commons^™

The Age And Origin Of Precambrian Orthogneiss Of The Grouse Creek Block, Northern Utah And Southern Idaho, Skadi Kobe

Fall Student Research Symposium 2020

New geochronologic and isotopic analyses from the Grouse Creek block (GC) provide insight into the assembly of western Laurentia during the late Archean to Paleoproterozoic and establish the influence of the GC in the evolution of Yellowstone-Snake River Plain hotspot magmatism in the central Snake River Plain. The GC is primarily exposed in the Albion-Raft River-Grouse Creek metamorphic core complex of northern Utah and southern Idaho and includes a complex assemblage of orthogneiss, schist, amphibolite, and metasediments intruded by Oligocene plutons and overlain by Cenozoic sedimentary units. Many investigations of the GC have focused on the structural evolution of the …

Hazard Analysis Of A Segment Of Highway Sr-12 Through Bryce Canyon National Park, Southern Utah, Tomsen Reed

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Over 2.6 million people travel along highway SR-12, a National Scenic Byway, through Bryce Canyon in southern Utah each year. This highway is a major thoroughfare for tourists traveling to Bryce Canyon National Park, Grand Staircase-Escalante National Monument, and other scenic attractions. SR-12 is susceptible to rockfall and landslide hazards where it descends from the Paunsaugunt Plateau into Tropic Canyon, and these hazards have potential consequences of economic loss due to travel delays for tourists and commodities, and possible loss of life. Rockfall could have devastating effects at this location because of the traffic volume, sharp turns, low visibility, and …

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 …

Collaborative Research: Constraining The Tempo And Dynamics Of Cambrian Earth Systems In Western Laurentia, Carol M. Dehler

Funded Research Records

No abstract provided.

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 …

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 …

Fire Suppression Impacts On Fuels And Fire Intensity In The Western U.S.: Insights From Archaeological Luminescence Dating In Northern New Mexico, Christopher I. Roos, Tammy M. Rittenour, Thomas W. Swetnam, Rachel A. Loehman, Kacy L. Hollenback, Matthew J. Liebmann, Dana Drake Rosenstein

Geosciences Faculty Publications

Here, we show that the last century of fire suppression in the western U.S. has resulted in fire intensities that are unique over more than 900 years of record in ponderosa pine forests (Pinus ponderosa). Specifically, we use the heat-sensitive luminescence signal of archaeological ceramics and tree-ring fire histories to show that a recent fire during mild weather conditions was more intense than anything experienced in centuries of frequent wildfires. We support this with a particularly robust set of optically stimulated luminescence measurements on pottery from an archaeological site in northern New Mexico. The heating effects of an October 2012 …

Structural Controls On Crustal Fluid Circulation And Hot Spring Geochemistry Above A Flat‐Slab Subduction Zone, Peru, Brandt E. Scott, Dennis L. Newell, M. J. Jessup, T. A. Grambling, C. A. Shaw

Geosciences Faculty Publications

Hot spring geochemistry from the Cordillera Blanca and Cordillera Huayhuash, Peru, reveal the influence of crustal‐scale structures on geothermal fluid circulation in an amagmatic region located above a flat‐slab subduction zone. To test the influence of contrasting modes of faulting in these regions, springs were targeted along the Cordillera Blanca detachment fault, within its hanging wall, in the footwall of the detachment, and in the Cordillera Huayhuash. Hot springs along the Cordillera Blanca detachment fault zone are associated with recent extension and normal faulting, and those in its footwall and the Cordillera Huayhuash are located in the Marañon fold and …

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 …

Links Between Eruptive Styles, Magmatic Evolution, And Morphology Of Shield Volcanoes: Snake River Plain, Idaho, Katelyn J. Barton, Michelle Hurst

Utah Space Grant Consortium

Despite their similar ages and geographic locations, two low-shield volcanoes on the eastern Snake River Plain, Idaho, Kimama Butte (87 ka) and Rocky Butte (95 ka), have strikingly different profiles. In this study, these two volcanoes are examined to determine the connections between chemical composition, intensive parameters, eruption style, and topographic features of basaltic shield volcanoes. Because lava temperature, magma viscosity, and chemical composition overlap at the two volcanoes, they are probably not important controls on the differences in morphology. The main difference at the two shields, aside from general vent morphology, is the presence of late-stage, phenocryst-rich, high viscosity …

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott

Geosciences Faculty Publications

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick …

Collaborative Research: Quantifying Crustal Hydration Effects In The Colorado Plateau From Xenoliths, Dennis Newell

Funded Research Records

No abstract provided.

Crustal Composition And Moho Variations Of The Central And Eastern United States: Improving Resolutionand Geologic Interpretation Of Earthscope Usarray Seismic Images Using Gravity, H. L. Zhang, D. Ravat, Anthony R. Lowry

Geosciences Faculty Publications

EarthScope's USArray Transportable Array has shortcomings for the purpose of interpreting geologic features of wavelengths less than the Transportable Array station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce nonuniqueness in the interpretation of gravity anomalies. We model gravity anomalies from previously derived density variations of sedimentary basins, crustal V_p/V_s variation, Moho variation, and upper mantle density variation derived from body wave imaging informed by surface wave tomography to estimate V_p/V_s. Although average densities and density contrasts for …

Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life., Patricia Fryer, C. Geoffrey Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John W. Shervais, Elmar Albers, Barbara Bekins, Baptiste Debret, Jianghong Deng, Yanhui Dong, Philip Eickenbusch, Emanuelle Frery, Yuji Ichiyama, Richard Kevorkian, Et Al.

Geosciences Faculty Publications

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean …