Theses and Dissertations at Montana State University (MSU)
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Item Understanding the Coprophilous fungus Sporormiella as a proxy for megaherbivores(Montana State University - Bozeman, College of Letters & Science, 2020) Ulrich, Barbara Carol; Chairperson, Graduate Committee: Cathy WhitlockIn many studies, the presence of the coprophilous fungus Sporormiella in Quaternary sediments has been interpreted as evidence of past megaherbivore activity. Despite its use as an ecological proxy, little is known about the taxonomy and life history of Sporormiella, and the taphonomic processes that lead to its preservation in lake sediments. This information underlies its utility to interpret past herbivore presence and abundance. Present-day bison (Bison bison) dung from Yellowstone National Park was examined to explore the production, dispersal, transportation, deposition, and preservation of Sporormiella there. While Sporormiella was found in dung samples, sediments from two lakes frequently visited by bison failed to yield Sporormiella spores. Laboratory preparation techniques were modified to increase the likelihood of Sporormiella spore survival, yet no spores were identified with the new treatment. Although the occurrence of spores in lake-sediment samples may indicate herbivore presence, our study suggests that spore absence does not necessarily indicate an absence of herbivores. We attribute the absence of spores in sediments to local climatic and seasonal factors that may affect production and transport in the watershed, sedimentary processes that may destroy spores after deposition, and harsh laboratory processing techniques that may damage or destroy spores. More research remains to be done to evaluate the importance of these factors before using Sporormiella as a reliable proxy of herbivore activity.Item Hydrothermal influences on the Holocene environmental history of central Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2020) Schiller, Christopher Michael; Chairperson, Graduate Committee: Cathy Whitlock; Cathy Whitlock, Kathryn L. Elder, Nels A. Iverson and Mark B. Abbott were co-authors of the article, 'Erroneously old radiocarbon ages from terrestrial pollen concentrates in Yellowstone Lake, Wyoming, USA' in the journal 'Radiocarbon' which is contained within this dissertation.; Rosine Cartier, Cathy Whitlock and Lisa A. Morgan were co-authors of the article, 'Multi-proxy record of Holocene paleoenvironmental conditions from Yellowstone Lake, Wyoming, USA' submitted to the journal 'Quaternary science reviews' which is contained within this dissertation.; Cathy Whitlock, Sabrina R. Brown and Petra Zahajska were co-authors of the article, 'Holocene geo-ecological evolution in Lower Geyser Basin, Yellowstone National Park' submitted to the journal 'Geological Society of America bulletin' which is contained within this dissertation.; Cathy Whitlock, Mio Alt and Lisa A. Morgan were co-authors of the article, 'Vegetation responses to Quaternary volcanic and hydrothermal disturbances in the northern Rocky Mountains and Greater Yellowstone Ecosystem' in the journal 'Palaeogeography, Palaeoclimatology, Plaeoecology' which is contained within this dissertation.The postglacial vegetation history of Yellowstone National Park is well established by past paleoecological studies, but the role of hydrothermal activity--pervasive in areas of the park--in that history is poorly understood. To address this unknown, pollen and charcoal records were examined from lake sediment cores at multiple sites in central Yellowstone National Park to reconstruct Holocene vegetation. First, radiocarbon ages obtained from pollen concentrates were compared with other age controls at Yellowstone Lake, revealing ages that were up to 4300 cal years too old. Erroneous ages were due to either old carbon contamination from magmatic or hydrothermally degassed CO 2 or old pollen reworked from an unknown source. Second, Holocene vegetation and fire history were reconstructed from a Yellowstone Lake sediment core. The record was characterized by gradually increasing closure or extent of Pinus contorta forest and increasing fire activity to the present, consistent with reduced summer insolation creating cooler, effectively wetter conditions in central Yellowstone National Park. No impact of hydrothermal activity was detected in the regional Holocene-long vegetation and fire histories. Third, Holocene vegetation and fire history were studied at Goose Lake in Lower Geyser Basin, an area with abundant modern hydrothermal activity. The vegetation and fire history diverged from the regional trend at 3800 cal yr BP, synchronous with geochemical indicators indicating reorganization of hydrothermal activity in the basin, suggesting an abrupt ecological response to shifting hydrothermal activity. Finally, a variety of volcanic and hydrothermal processes were investigated as disturbances in the Northern Rocky Mountains and Yellowstone National Park through high-resolution pollen analysis. Hydrothermal explosion deposits were found to be synchronous with conifer morality, in some records, indicating that the effects of hydrothermal explosions are local and short-lived. At a regional scale, it is evident that vegetation changes were chiefly responding to millennial-scale, insolation-driven climate change. However, the impacts of hydrothermal activity were locally important where pervasive, as in Lower Geyser Basin, and in areas recently affected by hydrothermal explosions.Item Construction and modification of debris-flow alluvial fans as captured in the geomorphic and sedimentary record: examples from the western Sangre de Cristo Mountains, south-central Colorado(Montana State University - Bozeman, College of Letters & Science, 2020) Nicovich, Sylvia Rose; Chairperson, Graduate Committee: Mary S. Hubbard; James G. Schmitt (co-chair); James Schmitt was a co-author of the article, 'Deposition and modification of debris-flow alluvial fans, western rangefront of the Sangre de Cristo Mountains, south-central Colorado' submitted to the journal 'Journal of sedimentary research' which is contained within this dissertation.; Jim Schmitt, Ralph Klinger and Shannon Mahan were co-authors of the article, 'Late Pleistocene record of surface-modifying processes on the Pioneer debris-flow alluvial fan, San Luis Valley, Colorado' submitted to the journal 'Geological Society of America bulletin' which is contained within this dissertation.; James Schmitt was a co-author of the article, 'Impact of wind-blown sediment on the Pioneer debris-flow alluvial fan, south-central Colorado: concepts of fan activity' submitted to the journal 'Geosphere' which is contained within this dissertation.Alluvial fans and their deposits in the stratigraphic record are key in unraveling intricacies of landscape, tectonic, and climatic dynamics, though integrative geomorphologic and sedimentologic studies that comprehensively evaluate processes which build and modify fans are lacking. Therefore, a gap within the current body of literature exists concerning the sedimentological signature of depositional and surface-modifying processes on alluvial fans. This dissertation presents the sedimentological characteristics, both surficial and in the sedimentary record, of processes that build and modify alluvial fans while revisiting the contemporary concept of what defines an active surface. Detailed analysis of a suite of Quaternary active debris-flow alluvial fans on the western range front of the Sangre de Cristo Mountains in south-central Colorado was made using integrative sedimentological and geomorphic analysis, facies and soils mapping, along with infrared stimulated luminescence (IRSL) geochronology to document timing of fan construction and modification processes recorded in the alluvial fan deposits. Analysis of surface geomorphology, facies assemblages, and particle-size distributions of matrix from various facies of exposed alluvial fan deposits were also applied. These data show a clear distinction between sedimentary facies that represent processes of the primary depositional lobe surfaces versus those operating during periods of non-primary deposition, dominant on abandoned lobes. Primary processes on depositional lobes are debris flow and hyperconcentrated flow with minimal secondary modifying processes. Overland flow, input of eolian material, pedogenesis, and rock and mineral weathering are the main secondary modifying processes that govern abandoned lobes. Addition of wind-blown material, a secondary modifying process, plays a significant part in the sedimentary processes that operate on alluvial fan surfaces, ultimately influencing fan smoothing by mobilizing material derived from primary processes.Item Biotic and physical responses to biomimicry structures in a Rocky Mountain incised stream(Montana State University - Bozeman, College of Letters & Science, 2020) Reinert, James Holden; Chairperson, Graduate Committee: Lindsey Albertson; Lindsey K. Albertson and James R. Junker were co-authors of the article, 'Biotic and physical responses to biomimicry structures in a Rocky Mountain incised stream' submitted to the journal 'River research and applications' which is contained within this thesis.An increase in stream degradation resulting from land use change has motivated an increase in restoration efforts across the globe. Post-restoration monitoring is still lacking, however, and does not always incorporate biotic responses to changes in the physical template. Beaver mimicry structures (BMS) are becoming a popular tool to restore degraded streams throughout the American west, but relatively little is known about how these installations influence both biotic and abiotic factors, with consequences for ecosystem functioning. We monitored basal resource deposition and macroinvertebrate density, biomass, and production to quantify functional responses to BMS installations. We compared conditions at BMS sites to naturally occurring beaver dam and reference riffle sites in a low-gradient stream in southwest Montana. Thermal ranges were contracted, and daily maximum temperatures increased at BMS sites compared to reference riffle sites. Deposition of fine sediment and basal resources was similar at beaver and BMS sites, and both were higher than reference riffles. Densities and production of macroinvertebrates were higher at the BMS sites compared to reference sites and similar to beaver sites due to changes in physical habitat and basal resource availability, reflected by increases in production of shredders (beaver) and collector-gatherers (BMS). In this study site, changes to the physical template using BMS appear to have strong impacts on biotic functional responses, creating habitats similar to target conditions of natural beaver dams. Future research should consider the extent of degradation and temporal limitations of monitoring schemes to incorporate BMS into standard restoration practice. Functional response metrics provide an important and mechanistic approach to determine the efficacy of process-based stream restoration practices.Item Sequence stratigraphic framework of the late Devonian (Frasnian) Duperow Formation in western and central Montana(Montana State University - Bozeman, College of Letters & Science, 2019) Steuer, Christopher Johann; Chairperson, Graduate Committee: David W. BowenThe Late Devonian Duperow Formation in western and central Montana and it's equivalent lower Jefferson Formation, is comprised of shallow marine carbonate strata deposited on the western margin of North America. It has produced significant volumes of oil and natural gas in the Alberta and Williston basins where the sequence stratigraphic framework of the formation is well-documented. However, in western and central Montana, the Duperow remains largely understudied. Additionally, at Kevin Dome, in northwest Montana, the Duperow hosts a large naturally occurring carbon-dioxide (CO^2) accumulation which is a potential economic resource and an analog for CO^2 sequestration over geologic time scales. The goal of this study is to determine the facies relationships and sequence stratigraphic architecture of the Late Devonian Duperow Formation in western and central Montana. This interpretation could help in exploration for oil and natural gas and provide useful information to aid in future carbon sequestration efforts. Multiple data sets are used in this study to best constrain depositional environments on the platform during Duperow deposition. Seven measured sections, three drill cores with associated well-logs, and forty-one thin sections are used to characterize facies, facies associations, parasequences, parasequence sets and sequences of the Duperow Formation and to construct the sequence stratigraphic framework within which these strata occur. Ten lithofacies comprising six lithofacies associations allow the interpretation of six depositional environments responsible for deposition of the Duperow Formation. The Duperow thins from the west and north onto the Central Montana Uplift, a paleohigh at the time, and thickens into the Central Montana Trough, a sub-basin on the platform. Two 2nd order and seven 3rd order sequences are interpreted from measured sections. Sequences are comprised of a transgressive systems tract and a highstand systems tract with no evidence for lowstand strata on the shelf. Transgression across the Central Montana Uplift did not occur until after the basal sequence boundary of the upper 2nd order sequence. Prior to this transgression, sequences lapped out before reaching the Central Montana Uplift. Overall, the Duperow in central and western Montana exhibits retrogradational stacking and thus is part of the transgressive systems tract of a lower-order megasequence.Item Meteoric 10Be in lake sediment cores as a measure of climatic and erosional change(Montana State University - Bozeman, College of Letters & Science, 2017) Jensen, Rachel Elizabeth; Chairperson, Graduate Committee: Jean Dixon; Jean L. Dixon was a co-author of the article, 'A quantative framework for understanding past environmental change using 10 BE in lake sediments' submitted to the journal 'Earth surface processes and landforms' which is contained within this thesis.; Jean L. Dixon was a co-author of the article, 'Meteoric 10 BE in Blacktail Pond, Yellowstone, as a recorder of paleoenvironmental change' submitted to the journal 'GeoSciences' which is contained within this thesis.Developing tools that trace Earth-surface processes is necessary to quantify the complex controls on geomorphological, geochemical, and climate records. This thesis explores the potential of one such tool, meteoric 10 Be. The delivery of meteoric 10 Be to the surface varies with precipitation and its adsorption to sediment has proven useful in studies of erosion. These characteristics indicate that meteoric 10 Be in lake sediments varies under changing climate and changing sediment influx, making it a potential recorder of past climate and landscape processes. To examine the controls on meteoric 10 Be concentrations in lake sediments, we develop a model that predicts concentrations of 10 Be in lake sediments as a function of atmospheric flux, sedimentation rate, and terrigenous input. The model was applied to two published datasets of 10 Be profiles in lake sediments from different settings to assess the sensitivity of individual controls on 10 Be concentration. Results show that while a variety of environmental conditions influence 10 Be in lake sediments, these can be quantified with surprisingly simple parameters. Assessment of the relative importance of model parameters requires the comparison of 10 Be concentrations in well-dated lake cores to independent paleoenvironmental proxies. We further validate this model and explore the application of meteoric 10 Be in lake archives, by exploring a new system, Blacktail Pond in Northern Yellowstone, for which a wealth of paleoenvironmental data exists. We present new meteoric 10 Be data in the core, and compare to model predictions based on sedimentation rates of both autochthous and allocthonous sediments and changes in the flux of meteoric 10 Be with precipitation. Surprisingly, patterns of measured 10 Be concentrations in Blacktail Pond sediments show little relationship to predicted concentrations, despite being of similar magnitude. Based on this analysis, we suggest that small lake systems may be most problematic for 10 Be analyses as they are most sensitive to changing 10 Be concentrations relative to changes in model parameters. This work provides a new quantitative framework to assess the control of sedimentation rates, inputs of allocthonous sediments, and hydroclimate in determining the 10 Be concentrations measured in lake sediments, and highlights the potential and limitations of meteoric 10 Be in quantifying past environmental changes.Item Assessment of streambank erosion along the North Fork Flathead River, northwestern Montana(Montana State University - Bozeman, College of Letters & Science, 1988) Ruth, John HelmsItem Irrigation-related sediment deposition and suspended sediment effects on saturated hydraulic conductivity(Montana State University - Bozeman, College of Agriculture, 1995) Parwana, NoorjahanItem Influence of groundwater on streambank soil moisture content, storm runoff production and sediment production in a semi-arid watershed, southwest Montana(Montana State University - Bozeman, College of Letters & Science, 1989) Aspie, Jon MatthewItem Sedimentology, provenance, and paleotectonic significance of the cretaceous Newark Canyon Formation, Cortez Mountains, Nevada(Montana State University - Bozeman, College of Letters & Science, 1988) Suydam, James David