Theses and Dissertations at Montana State University (MSU)
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Item An expanded lava creek tuff eruption: re-mapping the Sour Creek Dome, Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2023) Salazar, Raymond Dale; Chairperson, Graduate Committee: Madison MyersThe ~1000 km 3, ~630 ka Lava Creek Tuff is the product of the younger major caldera- forming eruption of the Yellowstone Volcanic Field. It is currently mapped as two ignimbrite units, hot dense flows of ash, gas, and molten material, termed members A and B, with accompanying widespread ashfalls over the western U.S. This view of the Lava Creek Tuff, and its eruption, was complicated when two, visually distinct, ignimbrites were recognized on the Sour Creek dome in Yellowstone National park (Wilson et al., 2018). These visually distinct ignimbrites on the Sour Creek dome were initially mapped as the older (2.08 Ma) Huckleberry Ridge Tuff, however, when dated by U - Pb on zircon and 40Ar/39Ar on sanidine the ignimbrites returned ages analytically indistinguishable from the Lava Creek Tuff (0.631 Ma). In the newly dated ignimbrites, one unit is found as clasts of dense welded tuff withing a lag deposit which is conformably overlain by a second, cliff-forming, densely welded ignimbrite that contains scoria. This study further complicate matters due to the discovery of two additional, previously unrecognized, ignimbrites while mapping on the Sour Creek dome, bringing the total to four ignimbrites. Physical and chemical evidence suggests there were multiple magma bodies tapped during the eruptions. This project broadens our understanding of the four ignimbrites documenting their spatial distribution and source area(s) and determine how they relate geochemically to the established members A and B. This was done through field mapping, thin section examination, and whole-rock and single crystal geochemistry. This resulted in a revised understanding of the Lava Creek Tuff stratigraphy and holds implications for reevaluating the eastern boundary of the Yellowstone Caldera.Item A mess of rotten eggs from the Two Medicine Formation, Montana(Montana State University - Bozeman, College of Letters & Science, 2024) Tucker, Katherine Lydia; Chairperson, Graduate Committee: David J. VarricchioThe Two Medicine Formation of Montana is known for producing many dinosaur eggs in varying states of preservation. An unusual clutch of eggs MOR 11881 was recently found in the formation that exhibits some distinctive preservation features. The purpose of this research is to describe this clutch using multiple techniques to identify and better understand its taphonomic history. To do this the clutch was prepared by removing sediment from around the eggs, then examined using light microscopy, scanning electron microscopy (SEM), cathodoluminescence (CL), energy dispersive x-ray spectroscopy (EDX), and electron backscatter diffraction analysis (EBSD). Preparation uncovered eleven partially compressed ellipsoidal eggs in the clutch. Microscopy of the eggshell revealed that it is made of two structurally distinct layers. The lower layer at the base of the eggshell is here referred to as the blocky layer based on the blocky texture of the crystals in SEM images. This layer is sometimes interrupted by a phosphatic dark region. The second layer is the lobed layer found along the outer surface of the eggshell. It is characterized by lobes of blocky crystals surrounded by smaller radiating crystals. In addition to the eggshell the eggs also preserve a phosphatized eggshell membrane, two distinct types of pellets, large masses of collophane crystals and hyphae like structures. Unaltered eggshell is found in the sediment surrounding the clutch. The eggshell of the MOR 11881 clutch does not match any described ootaxon but is similar to eggshell found at the Egg Mountain quarry which was never identified. The unusual structure of the eggshell could be the result of multiple stages of alteration. Several structures in the eggshell including the lobes and the dark region are most likely the result of alteration. The presence of unaltered eggshell near the eggs indicates that the source of alteration was the decay of the eggs as recorded by their contents. This decay also produced the conditions necessary for the exceptional preservation of the eggshell membrane.Item Structural control of the Norris Hot Springs and associated geothermal system(Montana State University - Bozeman, College of Letters & Science, 2023) Wafer, Mia Peyton; Chairperson, Graduate Committee: Andrew K. LaskowskiMany active and productive geothermal systems are structurally controlled, suggesting that certain structural configurations have higher potentials for geothermal energy. Analyzing potential productive geothermal wells is known as geothermal play fairway analysis (PFA). Identifying these high potential structural configurations is another way to locate geothermal systems without surface expressions, which represent an unquantified natural resource for geothermal energy. By studying geothermal systems with surface expressions, I move closer to being able to locate additional natural resources. The Norris Hot Springs, located in the foothills of the Tobacco Root Mountains, Southwestern Montana, presents a novel study area to test structural control on geothermal system development. I combine geologic mapping, UAV-based photogrammetry, zircon U-Pb geochronology, seismic data, and 3D geologic modeling to date and interpret the multistage development of local structures and their influence on the geothermal system beneath the Norris Hot Springs. A comprehensive structural model suggests the geothermal system associated with the Norris Hot Springs is hosted by a deep network of faults and fractures in Precambrian gneiss basement. A nearby fault system primarily comprised of high angle NNW-SSE trending normal faults, which often display pervasive alteration and polymetallic vein mineralization, likely connects surficial features with deeper reactivated Laramide-era structures. A primary goal of this study was to investigate the benefits of supplementing traditional field work with novel methods. Results from this study demonstrate the utility of combining geologic mapping, 3D modeling, structural analysis, 3D modeling and UAV surveys for geothermal exploration and constrain the timing and influence of local faulting on geothermal activity at the Norris Hot Springs.Item First digital forelimb reconstruction and range of motion assessment of the late Cretaceous dinosaur Troodon formosus(Montana State University - Bozeman, College of Letters & Science, 2023) Serio, Michael Anthony; Chairperson, Graduate Committee: David J. VarricchioTroodon formosus (Troodon) is a theropod dinosaur from the Late Cretaceous of North America primarily known from fragmentary fossil material. Hypothesized to hunt small game, Troodon, like many theropods, may have actively engaged its forelimbs to aid hunting behavior. Furthermore, the complexity of preserved nests associated with Troodon suggest it had sufficient range of motion and dexterity to use its forelimbs to manipulate its eggs. Additionally, Troodon's evolutionary position as one of the closest groups to living birds could indicate important information about the evolution of the avian wing. However, no complete forelimb material has yet been found for Troodon, and as such a complete reconstruction and range of motion (ROM) estimate of its forelimbs has yet to be attempted. This study aims to address these hypotheses and shortcomings by leveraging recent digital modelling technology to create the first forelimb reconstruction and ROM for Troodon. To overcome preservation limitations, surface scans from multiple Troodon fossils housed in the Museum of the Rockies (Bozeman, Montana) were digitally combined to reconstruct most of a forelimb. From this model, digital articulation in the software package Maya was compared with physical articulation ROM methods using 3D printed copies of the forelimb. The maximum angle of allowed motion for each forelimb joint until bone-on-bone contact was assessed. Results show increased flexion over extension in Troodon's joints, consistent with closely related species. However, Troodon also shows higher manual extension than close relatives. The humerus is also shorter and stockier, showing mechanical specialization for strength vs speed, and convergent features with primitive theropod species. These ROM and morphological differences imply a deviation in hunting strategy or forelimb utility and a deviation from avian forelimb morphology. Total manual ROM results cannot confirm whether Troodon was able to grasp its eggs and small prey single-handed, but two-handed apprehension remains feasible. This study utilized digital and physical ROM methods, analyzing for the first-time specimens that would have been previously overlooked. These results shed light on both the foraging and reproductive behavior of Troodon and have implications for understanding the evolution of modern avian reproductive behavior and the dinosaur-bird transition.Item Change in provenance and sediment routing history of the Miocene-Pleistocene Bengal Fan, Indian Ocean using detrital zircon (U-Th)/He thermochronology(Montana State University - Bozeman, College of Letters & Science, 2023) Dixon, Timothy Spencer; Chairperson, Graduate Committee: Devon A. Orme; This is a manuscript style paper that includes co-authored chapters.The Ganges-Brahmaputra river system carries thousands of tons of sediment from the Himalaya each year to the submarine Bengal Fan within the Indian Ocean. Deposition of sediments to the fan has been ongoing since at least late-Oligocene time (Krishna et al., 2016), preserving a record of Himalayan tectonics and topographic evolution (Blum et al., 2018). IODP Expedition 354 (2015) collected 1.7 km of sediment core from the Bengal Fan to expand the record of Himalayan sediment routing (France-Lanord et al., 2016). Detrital zircon U-Pb data from core samples reflect five major tectonostratigraphic sequences from the Himalaya-Tibet Orogen (Blum et al., 2018). Age populations appear to vary temporally, suggesting change in erosion rates and sediment routing through time, especially apparent during the Pliocene-Pleistocene transition. This research uses detrital zircon (U-Th)/He thermochronology, double dating analyses, and sediment mixing model approaches to fingerprint changes in sediment routing and river deposition to the Bengal Fan. (U-Th)/He analyses are used to quantify rock uplift and exhumation experienced in the Himalayas, facilitating lag-time interpretations across Miocene-Pleistocene time. To interpret the Bengal Basin sink record, a compilation of mid to low-temperature thermochronology datasets across the Himalaya-Tibet orogen is presented for characterization of modern-day thermochronologic age signals. This database highlights orogen wide trends in cooling dates that show younging apatite/zircon (U-Th)/He and fission tracks in the frontal Himalaya and syntaxes, and a younging trend in 40Ar/39Ar dates towards the orogen center. Zircon (U-Th)/He analyses of Bengal Fan sediments deposited 6.20 - 0.13 Ma reveal cooling dates from ~0.28 + or - 0.03 - 540.15 + or - 6.13 Ma. Age populations vary greatly between Miocene-Pleistocene time, with notable loss of >23 Ma populations between Miocene-Pliocene time and increasing 5.3 - 23 Ma populations across the Pliocene-Pleistocene transition with decreasing depositional lag-times. Comparison of age populations to previously recorded cooling dates from the orogen reveal shifts from Brahmaputra to Ganges sources between Miocene-Pliocene time before reaching a mixed drainage signal in the middle Pleistocene. Observed shifts in sediment provenance are attributed to coupled tectonic-climatic forces with regional acceleration of exhumation in the Himalaya, onset of northern hemisphere glaciation and increased denudation of the frontal-Himalaya during Miocene-Pleistocene time.Item Addressing the state of Yellowstone National Park's geologic maps using traditional and novel approaches(Montana State University - Bozeman, College of Letters & Science, 2023) Kragh, Natali Ann; Chairperson, Graduate Committee: Madison MyersAccurate geologic mapping is especially important for public land, such as Yellowstone National Park, so land managers can mitigate safety risks, mindfully place infrastructure, and communicate scientific knowledge to the public. The geology of Yellowstone National Park (YNP) has been repeatedly mapped over the last century by multiple geologists with varying perspectives and mapping goals. The most recent efforts have resulted in a patchwork of twenty-one different scale maps (one 1:125,000, one 1:100,000, and nineteen 1:62,500). Presently, there exists significant promise of publishing a higher resolution, seamless map of YNP; however, it has become apparent that many of the current internal maps disagree along their shared boundaries. This study aims to address these discrepancies using both traditional and novel techniques and determine if mapping along boundaries is the best practice towards creating a seamless map. In total, 485 areas of disagreement, referred to here as boundary problems, were identified. During this study, 66 boundary problems were resolved. Each resolved boundary problem was aided by traditional mapping techniques (i.e., field mapping, field petrography, sample collection, and limited geochemistry and thin section work). However, some areas could not be addressed by field methods alone and required a more substantial analytical approach. Three "case studies" were chosen to highlight how geochemistry could aide in mapping in YNP: 1) a geochemical, textural, and age analysis of "dacite" units found throughout the north and northwestern portions of YNP and the Greater Yellowstone Region, 2) compiling a geochemical database to compare and correlate known rock units to unrecognized outcrops found in the field, 3) a novel technique using Pb isotopes in detrital plagioclase crystals from volcaniclastic units to establish a volcanic source for the units. These approaches resulted in varying success, but overall, lead to a better understanding of the work that needs to be done in YNP to publish an accurate, higher resolution geologic map. This work highlights the importance of reassessing older geologic maps and making necessary updates when the need is recognized, particularly along disagreeing shared boundaries using multiple techniques.Item Blackfoot traditional knowledge, bison drive lines, and geospatial analysis(Montana State University - Bozeman, College of Letters & Science, 2024) Edmo, Kendall Rae; Chairperson, Graduate Committee: David B. McWethy; This is a manuscript style paper that includes co-authored chapters.Bison drive lines provide material evidence of ancestral Blackfoot practices. The spatial dimensions of drive lines highlight a sophisticated understanding of bison-environment interactions and the strategic use of geographic landforms and environmental features to maintain a critical lifeway. Here we examine broad-scale landscape use patterns among prehistoric Blackfoot bison hunters on the Northwestern Plains through an analysis of a network of drive lines in traditional Blackfoot territory (US) using Geographic Information Systems (GIS) and previous archaeological and anthropological research. The findings of this study show that ancestral Blackfoot designed bison drive lines to be positioned in proximity to key landscape resources including water, forested areas, and wetlands and kettle lakes. This study builds on previous research that applies an Indigenous archaeological framework that incorporates ethnohistoric narratives and traditional knowledge to provide important context for understanding the relationship between ancestral Blackfoot, bison, and the cultural landscape. Examining the relationship between drive lines and landscape features helps advance our understanding of the Blackfoot knowledge system that has adapted and endured for millennia.Item Rethinking water conflict and cooperation: a re-analysis of interviews in Montana and an example study from the Big Hole River watershed(Montana State University - Bozeman, College of Letters & Science, 2024) Bjorklund, Erin Nicole; Chairperson, Graduate Committee: Sarah P. Church; This is a manuscript style paper that includes co-authored chapters.Climate change heightens the supply and demand imbalance for freshwater, increasing the potential for conflict between water users. However, conflict is not the only outcome, as water demands can also create space for cooperation. The Basins at Risk (BAR) scale is one of the most prominent numerical measurements for analyzing the level of conflict or cooperation in freshwater-related events reported in public news sources. However, few studies in the U.S. West and none within Montana have utilized this method and little has been done to investigate alternative applications of the BAR scale beyond news event analysis. Therefore, this study examines 1) water conflict and cooperation trends in Montana and 2) how interview data can contribute to nuanced understandings of water conflict and cooperation. The intensity and type of issue for water events in Montana were cataloged and analyzed in a re-analysis of 63 interviews conducted for the Montana Drought Vulnerability Assessment. Results revealed that from the perspective of Montanan water stakeholders, cooperation over water resources outweighs conflict, and low-intensity conflictive and cooperative events are more prominent. The re-analysis results informed the selection of an example study utilizing the BAR scale to analyze event data (n=314) and primary interviews (n=11) collected in the Big Hole Watershed, Montana. Event data was sampled from 7 Montana news sources between the years 2007 and 2023. Primary interviews were conducted in February, March, and April 2024 with a variety of stakeholders in the Big Hole River Watershed (e.g., anglers, ranchers, fishing guides, Big Hole Watershed Committee board members, Fish, Wildlife and Parks). These data show the value of including primary interviews in a study utilizing the BAR scale. Moreover, results from this study can help researchers and resource managers monitor and identify water conflict and cooperation, by showing a nuanced understanding of conflict and cooperation.Item When and where does irrigation water originate? Leveraging stable water isotopes and synthetic aperture radar to assess the complex hydrology of a snow-dominated catchment in southwestern Montana(Montana State University - Bozeman, College of Letters & Science, 2023) Rickenbaugh, Eliza Apple; Chairperson, Graduate Committee: Eric A. Sproles; This is a manuscript style paper that includes co-authored chapters.Many agricultural regions around the world rely on water stored in mountainous snowpacks for irrigation supply. Consequently, our current and future ability to produce food is threatened by more frequent, severe, and extended snow droughts. As these snow droughts intensify, water resource managers will need more efficient and accurate methods to characterize the snowmelt cycle and forecast water availability. Focusing on a montane headwater catchment in Southwestern Montana (423 km 2 in area, between 1465 m to 3270 m in elevation), we integrate in-situ and remotely sensed data to assess the relative contributions of groundwater and the current season's snowmelt to irrigation supply for water year (WY, Oct 1 - Sep 30) 2023. To understand the period over which snow contributes to stream water in this catchment, we analyze backscatter data from Sentinel-1 Synthetic Aperture Radar (SAR). This provides approximate dates of snowmelt runoff onset at 10 m resolution every twelve days. We find that the median date of snowmelt runoff onset in WY 2023 in this catchment was April 20, six days later than the 7-year median date of snowmelt runoff onset. To assess relative contributions to streamflow we compare stable water isotope ratios (deltaH2 and deltaO18) from biweekly samples of stream water at low elevations against monthly samples of snow and groundwater. Samples range in elevation from 1,475 m to 2,555 m. We find that stream water below the highest diversion point is predominantly composed of groundwater. Results demonstrate alignment between two disparate approaches for estimating temporal trends in snowpack contribution to stream flow. While our work focuses on a catchment in Montana, the efforts and approaches used are potentially applicable globally for agricultural regions that rely on snowmelt for irrigation.Item A framework for the quantitative assessment of new data streams in avalanche forecasting(Montana State University - Bozeman, College of Letters & Science, 2023) Haddad, Alexander Sean; Co-chairs, Graduate Committee: Eric A. Sproles and Jordy HendrikxData used by avalanche forecasters are typically collected using weather stations, manual field-based observations (e.g., avalanche events, snow profiles, stability tests, personal observations, public observations, etc.) and weather forecasts ("traditional observations"). Today, snow cover observations can be delivered via remote sensing (e.g., satellite data, UAV, TLS, time-lapse camera etc.). Forecasting operations can also use statistical forecasting, weather models, and physical modeling to support decisions. This paper presents a framework and methodology to quantify the impact these new, complex data streams have on the formulation of, and associated uncertainty of, avalanche forecasting. We use data from a case study in Norway. Avalanche forecasters in Norway assessed size (D), likelihood, avalanche problem, and hazard level for a highway corridor in Grasdalen, Stryn Norway. The control groups were given access to traditional observations. The experimental groups were given access to the same traditional data, but also near-real-time snow surface LiDAR data ("RS+"). In case study one the RS+ (n=10) consensus findings were a hazard level two steps lower than the control group (n=10). In case study two the traditional (n=10) and RS+ groups' (n=7) consensus findings assessed the northeastern avalanche path at the same hazard level. Assessing the southwestern slide path, the traditional group (n=10) and RS+ group (n=9) had the same consensus finding for hazard level. In 2 of 3 case studies, the RS+ groups had fewer selections for size, likelihood, and avalanche problem which indicates reduced uncertainty in their forecasts. Throughout the 2022-2023 winter season Norwegian Public Roads Administration avalanche forecasters performed a real-time experiment throughout the season - with and without additional RS+ data when forecasting. They agreed on hazard level in 6 of 10 forecasts. In the other 4 forecasts, RS+ forecasters assessed the hazard level higher than traditional data forecasts. When RS+ data reveals aspects of conditions that traditional observations did not detail, RS+ forecasters adjust their selections in the hazard matrix, resulting in greater clustering of their predictions, indicating reduced uncertainty. Due to uncertainty associated with avalanche forecasting, this framework for assessment should be used to track avalanche forecast efficacy and build a qualitative and quantitative historical record.