Physical Sciences and Mathematics Commons^™

The Curacautín Eruption Of Llaima Volcano, Chile, Aaron Asdale Marshall

Boise State University Theses and Dissertations

Mafic magmas are the most common magmas erupted on Earth and on rocky bodies in the Solar System. The low viscosity of mafic magmas results in eruptions that are primarily effusive to mildly explosive. Rarely, mafic magmas erupt as more violent, explosive events, and the causes of this transition in eruptive style are hotly debated. In this dissertation, I investigated the conditions in the conduit and shallow subsurface that generated the unusually explosive mafic, Curacautín eruption of Llaima volcano, Chile. The Curacautín ignimbrite (Ci) is a basaltic andesite ignimbrite consisting of four flow units of variable thicknesses. New ¹⁴C …

Machine-Learning Reveals Aftershock Locations For Three Idaho Earthquake Sequences, Spencer F. Wilbur

Boise State University Theses and Dissertations

I explore spatial and temporal aftershock patterns related to three instrumentally recorded earthquakes in Idaho -- the Sulphur Peak, the Challis, and the Stanley earthquakes. These three M > 5 earthquakes border the eastern Snake River Plain and lie within the Intermountain Seismic Belt and Centennial Tectonic Belt. Using machine learning for event detection and phase picking from local and regional seismic networks, I generate new aftershock catalogs. I locate more aftershocks than in the USGS catalog due to lower signal-to-noise detections. Using my phase picks, I locate aftershocks using a range of velocity models and select a catalog that represents …

Computational Approaches To Understanding Subduction Zone Geodynamics, Surface Heat Flow, And The Metamorphic Rock Record, Buchanan C. Kerswell

Boise State University Theses and Dissertations

Pressure-temperature (PT) estimates from exhumed high-pressure (HP) metamorphic rocks and global surface heat flow observations evidently encode information about subduction zone thermal structure and the nature of mechanical and chemical processing of subducted materials along the interface between converging plates. Previous work demonstrates the possibility of decoding such geodynamic information by comparing numerical geodynamic models with empirical observations of surface heat flow and the metamorphic rock record. However, ambiguous interpretations can arise from this line of inquiry with respect to thermal gradients, plate coupling, and detachment and recovery of subducted materials. This dissertation applies a variety of computational techniques to …

Translating Risk Information To Protective Action: Examining Household Response To Information About Earthquake Hazards And Risk, Carson C. Macpherson-Krutsky

Boise State University Theses and Dissertations

Natural hazards have been a part of the landscape since its existence, but they are becoming more devastating as they intersect with growing populations and as climate change increases their frequency and intensity. As these changes occur, the need to understand how to reduce disaster impacts becomes paramount. Despite growing concern and increasing costs of disasters over the past decade, household preparedness, which is at the foundation of disaster readiness, has seen little to no improvement. Using two research experiments, we adopt the Protective Action Decision Model (PADM; Lindell & Perry, 2004; 2012) as a framework to investigate what motivates …

An Integrative Approach For Environmental Assessment And Water Resources Management Using Direct Current Resistivity (Dc), Geographic Information System (Gis), Remote Sensing, And Gain And Loss Method, Dina Ragab Desouki Abdelmoneim

Boise State University Theses and Dissertations

Sustainable water resource management is a crucial national and global issue (Currell et al., 2012). In arid areas, groundwater is often the major source of water or at least a crucial supplement to other freshwater resources for agriculture, industry and domestic consumption (Vrba and Renaud, 2016). The complexity associated with groundwater-surface water interactions creates uncertainty about water resource sustainability in semi-arid environments, especially with urbanization and population growth. Flood irrigation in the early 1900s increased the shallow groundwater table in the Treasure Valley (TV), but with increasing irrigation efficiencies, they have been declining since the 1960s with a mean decline …

Mafic Explosive Volcanism At Llaima Volcano: 3d X-Ray Microtomography Reconstruction Of Pyroclasts To Constrain Shallow Conduit Processes, Pedro Antonio Valdivia-Munoz

Boise State University Theses and Dissertations

Mafic eruptions, which are typically effusive to mildly explosive, can produce much stronger explosive eruptions. Eruption style is determined by the ability of gas to escape through the permeable network. If the permeability is sufficiently high to reduce vesicle overpressure during ascent, the volatiles may escape from the magma, inhibiting violent explosive activity. In contrast, if the permeability is sufficiently low to retain the gas phase within the magma during ascent, bubble overpressure may drive magma fragmentation. Rapid ascent rates may induce disequilibrium crystallization, increasing viscosity and explosivity, and have consequences for the geometry of the vesicle network. Quantitative vesicle …

Assessing Soil-Related Terroir Factors In Sunnyslope District Vineyards Of Southwest Idaho, Rachael Nicole Haggen

Boise State University Theses and Dissertations

Terroir is the set of factors including climate, soil, and management practices that influence the character of a wine. Of these factors, soil texture and chemistry is a major determinant in wine grape quality (van Leeuwen et al., 2009). Understanding the characteristics of the soil is key to making decisions that support the production of the highest possible quality grapes from the resources available. Few studies have been conducted in the Snake River Valley AVA (SRVAVA). This study seeks to build upon the data already available and provide analysis of vineyard-scale terroir in a leading grape growing district of the …

Petrogenesis Of Off-Axis Lavas Erupted Along The 8˚20’ N Seamount Chain, East Pacific Rise, Molly Kassandra Anderson

Boise State University Theses and Dissertations

Lavas erupted at off-axis seamounts provide a window into mantle heterogeneity and melting systematics that are not easily observed on-axis at fast spreading mid-ocean ridges (MORs). This is because axial melts are efficiently mixed and homogenized within shallow axial magma chambers prior to eruption. To understand the deeper magmatic processes contributing to oceanic crustal formation, we examine the compositions of lavas erupted along a chain of off-axis seamounts, adjacent to the East Pacific Rise (EPR). Essential questions include: (1) What is the range of compositional variability erupted off-axis and how does that compare to lavas erupted on-axis? (2) Is there …

Evaluating Stable Isotope And Geochronologic Techniques For Paleoclimate Reconstruction: Case Study Of The Santa Cruz Formation, Argentina, Robin B. Trayler

Boise State University Theses and Dissertations

Stable isotope analysis has become the method of choice for many studies investigating the paleoecology and paleoclimate of fossil mammal faunas. While organic tissues (collagen, keratins, proteins) persist for < 10⁵ years highly mineralized tooth enamel is resistant to alteration and degradation and faithfully preserves its isotopic composition for millions (> 10⁶) years. Reconstructing past climates from these records relies on both understanding both micro-scale mechanisms of isotope incorporation into individual teeth, and macro-scale changes in isotope compositions over hundreds of thousands or millions of years. In this dissertation I address three questions.

First, how does the geometry and …

Protracted Thrusting Followed By Late Rapid Cooling Of The Greater Himalayan Sequence, Annapurna Himalaya, Central Nepal: Insights From Titanite Petrochronology, Jesse Bennett Walters

Boise State University Theses and Dissertations

Temperature-time (T-t) paths derived from coupled Zr-in-titanite thermometry and U-Pb geochronology are useful for examining middle-crustal tectonic processes. T-t data collected from the titanite-bearing calcsilicates of the upper Greater Himalayan Sequence (GHS) along the Marsyandi River, Annapurna Himalaya, illustrate a significantly different metamorphic history than previously recorded in central Nepal. Combined with traditional thermobarometry, textural relationships, and field mapping, titanite T-t data reveal a protracted history of mid-crustal tectonics. Peak Zr-in-titanite temperatures are 750-850 °C at 10-14 kbar. T-t paths are divided into two groups, which are separated by the Chame Shear Zone (CSZ). Group I (upper) rocks show cooling …

Geologic, Geochemical, And Geophysical Characterization Of The Gold Deposits Of The Horseshoe Bend Mining District, Idaho: Building A Four Dimensional Model For Ore Exploration, Joshua Ekhoff

Boise State University Theses and Dissertations

The Eocene aged Trans-Challis Fault System of central Idaho provides the tectonic and magmatic framework for a series of Au-Ag and Cu-Mo ore deposits. From its northernmost extension near Butte, Montana to its southwestern terminus in the Boise Basin of south-central Idaho the Trans-Challis Fault System is associated with some of the richest precious metal deposits found in Idaho. However, the southernmost tip of the Trans-Challis Fault System, composed of the Horseshoe Bend and Pearl mining districts, remains understudied, receiving little economic or academic attention. As a result, how the Pearl to Horseshoe Bend mining districts fit within the established …

Integrated Geophysical Exploration Of A Known Geothermal Resource: Neal Hot Springs, Clinton Ryan Colwell

Boise State University Theses and Dissertations

I present an integrated geophysical characterization of the Neal Hot Springs geothermal system in eastern Oregon. This newly established 23 MW geothermal production site is located in a region of complex geology and intersecting faults associated with two major extensional systems; the Oregon-Idaho Graben and the western Snake River Plain. The intersection of two dominant fault orientations, coupled with a high geothermal gradient from relatively thin continental crust and radioactive decay from a shallow granitic body, produces the pathways and heat needed for deep water circulation at Neal Hot Springs. New geologic mapping, geochemistry, and measurements from several boreholes in …

Cyclic Distributional Model Of The Late Moscovian Fusulinids In The Donets Basin (Ukraine) In Response To Eustatic Sea Level Fluctuations And Its Application In Biostratigraphy And Correlation, Rimma Khodjanyazova

Boise State University Theses and Dissertations

The continuous Pennsylvanian shallow-marine, paralic, siliciclastic succession in the Donets Basin is pivotal for correlation of marine and continental strata in northern Pangaea with coeval shallow-marine mainly carbonate strata in the Moscow Basin, a historical type area of Moscovian Horizons. The details of the history of establishment, lithostratigraphy and current biostratigraphy of Podolskian and Myachkovian Horizons in the Moscow Basin that are not readily available in Western literature are reviewed.

A model of cyclic recurrence (~0.6 —1myr) of three main fusulinid assemblages in the Pennsylvanian siliciclastic-carbonate succession in the Donets Basin is proposed. A Hemifusulina-association (A) indicates the onset …

The Geothermal System Near Paisley Oregon: A Tectonomagmatic Framework For Understanding The Geothermal Resource Potential Of Southeastern Oregon, Kyle Aaron Makovsky

Boise State University Theses and Dissertations

The tectonic and magmatic framework of southeast Oregon provides the conditions necessary for the existence of geothermal energy resources. However, few detailed studies of geothermal systems in this part of the Basin and Range have been conducted. Young bimodal magmatism and faulting associated with the High Lava Plains coupled with the encroachment of the Basin and Range tectonic province and potentially the Walker Lane have created the structural configuration, heat source, and secondary permeability necessary for geothermal systems in southeast Oregon. The relative contribution of these provinces to the overall tectonomagmatic framework is less well understood. In this study, the …

Age, Provenance, And Structure Of The Weatherby Formation, Eastern Izee Sub-Basin, Blue Mountains Province, Oregon And Idaho, Bryant Douglas Ware

Boise State University Theses and Dissertations

The terranes of the Blue Mountains province of eastern Oregon and west-central Idaho provide an important link between the geology of the North American Cordillera exposed in Canada and Alaska in the north and Nevada and California in the south. The Izee basin is a volcanic-rich sedimentary sequence onlapping the volcanic arc and accretionary mélange terranes of the Blue Mountains, and comprises the marine flysch Weatherby Formation at its eastern extent. This study sought to establish the stratigraphic and structural relationships between the Weatherby Formation and the proximal Baker and Olds Ferry terranes. Small-scale mapping, structural measurements, and geochronological data …

Determining Temperatures Of Deformation In Mylonites From The Scandinavian Caledonides, With Implications For The Thermal And Kinematic Evolution Of Orogens, Andrea Marilina Wolfowicz

Boise State University Theses and Dissertations

The Titanium-in-quartz (TitaniQ) thermobarometer was evaluated in ductilely sheared rocks (mylonites) from the Scandinavian Caledonides in comparison with several other thermometric methods, including: (1) TitaniQ thermometry in cross-cutting quartz veins, (2) garnet-biotite Fe-Mg exchange thermometry, (3) metamorphic phase equilibria, and (4) quartz microstructures as calibrated experimentally and empirically. In all instances, quartz vein temperatures mimic TitaniQ temperatures of the host rocks. Similarly, TitaniQ temperatures of dynamically recrystallized quartz, ranging from ~210°C at the thrust front to 475°C at the deepest structural levels, reflect the best estimate of the final temperature of deformation. Higher temperatures are also preserved locally and more …

Hillslope Asymmetry Maps Reveal Widespread, Multi-Scale Organization, Michael John Poulos

Boise State University Theses and Dissertations

Hillslope asymmetry is the condition in which oppositely-facing hillslopes within an area have differing average slope angles, and indicates aspect-related variability in hillslope evolution. As such, the presence, orientation, and magnitude of asymmetry may be a useful diagnostic for understanding process dominance. We present a new method for quantifying and mapping the spatial distribution of hillslope asymmetry across large areas. Resulting maps for the American Cordillera of the Western Hemisphere and the western United States reveal that hillslope asymmetry is widespread, with distinct trends at continental to drainage scales. Spatial patterns of asymmetry correlate with latitude along the American Cordillera, …

A 14,000-Year Record Of Wildfire And Alluvial Fan Deposition Reveals Relationships Among Fire, Climate, Vegetation, And Sediment Yields In The Middle Fork Salmon River, Idaho, Kerry Elizabeth Riley

Boise State University Theses and Dissertations

Changes in climate influence vegetation distributions and the frequency and severity of fire and post-fire erosion. While the frequency of large fires has increased on all vegetated continents over the last decade, it remains unclear whether recent large fires are extraordinary over millennial timescales. In the Middle Fork Salmon River of central Idaho, over 40% of the watershed has burned in the last 30 years and the subsequent increase in erosion from severely burned hillslopes has produced many large fire-related debris flows. Fires have burned throughout the steep topographic gradient of the watershed that encompasses high elevation sub-alpine and mixed …

Temporal And Spatial Analysis Of Stream And Groundwater Interactions, Ryan Eugene Warden

Boise State University Theses and Dissertations

Water chemistry and ecology of streams are impacted by the amount of water that exchanges between the surface water system and the adjacent saturated area, called the hyporheic zone, a dynamic area of stream channel sediments, which undergoes down-welling or up-welling of stream water. The rate and volume of water exchange between the surface water and the hyporheic zone are primary controls on stream ecology, but are challenging to assess. A common approach is to model the exchange rate with a one-dimensional advection-dispersion equation that includes solute exchange with transient storage zones, which is referred to as a transient storage …

Geochronologic And Isotopic Investigation Of The Koipato Formation, Northwestern Great Basin, Nevada: Implications For Late Permian-Early Triassic Tectonics Along The Western U.S. Cordillera, Nicholas Quentin Vetz

Boise State University Theses and Dissertations

The volcanics of the Early Triassic Koipato Formation of central Nevada unconformably overlie the Golconda Allochthon and, classically, this relationship has been used to define the timing of the Sonoma Orogeny as post-Middle Permian to earliest Triassic. However, the Koipato Formation represents a rather isolated magmatic succession, with other western U.S. Early Mesozoic igneous provinces determined to be younger or lacking rocks of Koipato age. This isolation, coupled with the fact that the Koipato Formation does not overlap the Golconda Allochthon, has left open two possible scenarios for its tectonic history: 1) the Koipato Formation represents the earliest, post-Sonoma Orogeny …

Evapotranspiration In The Riparian Zone Of The Lower Boise River With Implications For Groundwater Flow, Brady Allen Johnson

Boise State University Theses and Dissertations

Riparian zones in semi-arid regions often exhibit high rates of evapotranspiration (ET) in spite of low soil moisture content due to vegetation that is able to withdraw water from shallow aquifers. This work better defines the relationship between ET and the saturated zone by comparing the observed water table drawdown to analytically modeled drawdown in fully penetrating wells of an unconfined aquifer in response to daily ET flux. ET at the Boise Hydrogeophysical Research Site or BHRS (a riparian zone in a temperate, semi arid environment) is calculated following the approach of Batra et al. (2006) but uses site …

Geochemical, Isotopic, And U-Pb Geochronologic Investigations Of Intrusive Basement Rocks From The Wallowa And Olds Ferry Arc Terranes, Blue Mountains Province, Oregon-Idaho, Gene Alan Kurz

Boise State University Theses and Dissertations

Late Paleozoic to Mesozoic arc terranes comprising the Blue Mountains Province of northeastern Oregon and western Idaho are poorly understood in terms of the timing and duration of recorded magmatism and deformation. Intrusive basement rocks of the Wallowa and Olds Ferry arc terranes are investigated using a combination of highprecision U-Pb geochronology, radiogenic isotope and trace element geochemistry, and structural geology to help constrain their tectonomagmatic evolution and to provide a better understanding for the accretionary history of the Blue Mountains Province.

The Cougar Creek Complex is a compositionally diverse intrusive complex interpreted as the mid-crustal portion of the Wallowa …

Structural And Stratigraphic Age Constraints Of The Inskip Formation, East Range, Nevada: Implications For Mesozoic Tectonics Of Western North America, Joshua David Wilkins

Boise State University Theses and Dissertations

Structural, stratigraphic, and U-Pb geochronologic studies of the Inskip Formation of the north-central East Range place new constraints on the depositional age of the Inskip Formation and the timing of contractional deformation in the East Range, including Golconda thrusting. The Inskip Formation was initially considered Permian in age and to rest unconformably on the Valmy (or Leach) Formation (Ferguson et al., 1951). Later mapping by Whitbread (1978, 1994) divided the formation into the Upper and Lower Inskip Formation, both of which were inferred to be Mississippian in age. Laterreinterpretation of Whitebread’s (1994) work and new paleontological data revised the age …

Age And Isotopic Investigations Of The Olds Ferry Terrane And Its Relations To Other Terranes Of The Blue Mountains Province, Eastern Oregon And West-Central Idaho, Kyle P. Tumpane

Boise State University Theses and Dissertations

The Olds Ferry terrane of the Blue Mountains province is one of the numerous accreted terranes that comprise the western North American Cordillera. The Blue Mountains province is located in central and eastern Oregon, western Idaho, and extreme southeastern Washington, and is a crucial link in reconstructions of the North American Cordillera due to its position in an area with few visible terranes between the more extensively exposed terranes to the south in California and Nevada and to the north in Canada and Alaska.

New field evidence and U-Pb zircon geochronology for volcanics within the sedimentary onlap assemblages overlying the …

Internal Structure And Geochronology Of The Gerrei Unit In The Flumendosa Area, Variscan External Nappe Zone, Sardinia, Italy, Ashley V. Dack

Boise State University Theses and Dissertations

To investigate the stratigraphy and structural evolution of the Variscan Orogen of the External Nappe Zone, Sardinia, Italy, field work and geochronologic analyses were combined to assess both regional and orogen scale issues. Geologic mapping, structural analysis, and sampling in the Flumendosa area coupled with high-precision U-Pb zircon geochronology were used to determine the duration of Ordovician magmatic activity and the structural evolution of the Variscan Orogen.

To constrain the duration of magmatism for the Flumendosa area, U-Pb ID/TIMS zircon analyses were performed on samples from a lower volcanic flow of the Ordovician Volcanic Unit and an upper, syn to …

Holocene Fire And Climate In Rangeland Ecosystems Of Southwestern Idaho, Nathan Alfred Nelson

Boise State University Theses and Dissertations

Because rangelands are characterized by more arid climates than forested regions, traditional methods of reconstructing fire histories (e.g. fire-scars from trees or charcoal preserved in lake sediments) are limited. Charcoal preserved in alluvial fans and stream terraces provide a means of reconstructing a record of fires and geomorphic responses in rangeland ecosystems.

This study used dated charcoal from fire-related deposits and deposit characteristics to determine a record of fire and geomorphic response. Twenty-five samples collected from terraces and alluvial fans within the Wood Creek study area indicate three major periods of fire-related activity. From 4,400 – 4,000 cal yr BP, …