Whole-rock and mineral compositions of three eruptive deposits from the Twin Falls caldera, associated with the Yellowstone hotspot, provide a window into melt generation and evolution for hot, dry, A-type rhyolites. Three rhyolitic units were sampled via the Kimberly drill-core as a part of project HOTSPOT, a study focused on mantle plume and continental lithosphere interaction. Previous work has been done to collect high resolution U-Pb zircon ages, and Hf- and O-isotopic compositions. This study examined the geochemistry of apatite and zircon along with host rock compositions in the context of this previous work. The Kimberly core sampled the Shoshone Rhyolite (6.06 Ma, 120 m thick), Kimberly Member (7.70 Ma, 169 m thick), and Castleford Crossing Member (7.96 Ma, >1400 m thick). Apatite compositions more closely reflect the composition of their whole rock hosts than zircons. SiO2 content is higher in apatite of the Kimberly Member at (1.1 ± 0.75 wt.%), vs (0.72 ± 0.47 wt.%) for the Castleford Crossing and (0.84 ± 0.27 wt.%) for the Shoshone Rhyolite. REEs compensate for Si substitution in these apatites, with the Kimberly Member most enriched. Volatile contents in the apatites are typical of metaluminous A-type rhyolites, with very low Cl and high F concentrations. Average Ti-in-zircon crystallization temperatures were highest in the Castleford Crossing Member (847 ± 68°C), followed by the Shoshone Rhyolite (806 ± 78°C), and then the Kimberly Member (804 ± 70°C). Oxygen fugacity calculated from zircons has average ΔQFM values for the Shoshone (0.8), Kimberly (-0.2), and Castleford Crossing (0.2). Hf concentrations and Eu anomalies are comparable in zircons from all three units. REE patterns in zircons are also similar and concentrations of REEs in the Shoshone and Kimberly units are similar even though the whole rock compositions of all three units are distinct. Less than 15% of zircons in the Kimberly and Castleford Crossing rhyolites have CL-dark cores enriched in several REEs, U, and Th. These CL-dark cored zircons are likely xenocrysts entrained from chemically evolved granite and then overgrown with less enriched rims prior to eruption. There are several apatite grains with Si-LREE enriched rims in the Kimberly Member, which serves as further evidence of assimilation of silicic igneous rock by the Kimberly Member before eruption. Principal component analysis of the geochemical data distinguishes between the units using both whole-rock and apatite compositions. However, zircon compositions are not statistically distinguishable using PCA. A global comparison of Ti, U, Th, Yb, and Nb concentrations in zircons show that the zircons in the Central Snake River Plain are similar to zircons in Hawaiian basalts, while younger zircons from Yellowstone formed in cooler more differentiated magma. We propose that the zircon and apatite chemical patterns and trends confirm the A-type origin of Snake River Plain rhyolites and make it unlikely that they represent partial melts of felsic continental crust but are instead derived in large part from partial melts of young mafic crust--the midcrustal sill.

The national mammal of the United States, the American Bison (Bison bison) was once nearly extinct. Populations have recovered to the degree that thousands roam the Great Plains today. Due to their large numbers and body size, this species has an oversized impact on the ecological communities where it lives and is considered a keystone herbivore in modern North American grasslands. This study explores the detailed, seasonally resolved, paleoecology of seven bison from the Greater Yellowstone Ecosystem during the Late Holocene through stable isotope analyses and species niche modeling. Isotopic analyses of δ13C, δ15N, and δ18O reveal that bison within high elevations regularly foraged on C3 vegetation while traveling among the valleys and ridges of ecoregions similar to those of modern-day. Species distribution models provide a bimodal niche, with best-suited temperatures of 4-8°C and 16-26°C, and topographic ranges of 250-800m and 2,000-4000m.

This study examines opportunities for coordinated road management for purposes of ecosystem management. The coordination efforts in Greater Yellowstone provide a case study illustrating these opportunities. The study first reviews current literature about ecosystems, ecosystem management goals, benefits and the application of the concept to Greater Yellowstone. Issues of forest road management are also examined. The study then turns to a critique of current road management efforts in six National Forests of northwest Wyoming, southwest Montana and eastern Idaho; which are considered part of the Greater Yellowstone Ecosystem. Comparisons of road management planning and policy will be made primarily through examination of forest plans and engineering policies, and through personal communication with forest highway engineers and transportation planners. Recommendations for improving coordination of forest road management follow the critique. / Master of Urban and Regional Planning

The purpose of this study is to present both the educational and the geographical opportunities of Yellowstone National Park which is a region that provides inspiring areas of observation and experiences for American children.

Since their discovery in Yellowstone Lake in 1994, Lake Trout (Salvelinus namaycush) have been the object of an intensive gillnet suppression program due to their predation on native Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri). Managers are also interested in targeting early life stages to augment suppression. A benthic sled was used to sample for Lake Trout eggs at 24 locations, hypothesized to be spawning sites, that encompassed a range of depths, slopes, and substrate composition to determine the location and characteristics of spawning sites in Yellowstone Lake. Lake Trout eggs were collected at seven sites, five of which had not been previously confirmed as spawning sites. Habitat characterization at these sites indicate Lake Trout spawning in Yellowstone Lake is limited to areas with rocky substrate, but is not constrained to areas with interstitial spaces or contour breaks as is seen within the species' native range. Lake Trout fry were captured around Carrington Island, an additional spawning site in Yellowstone Lake, in 2014 and 2015. These fry were significantly larger at each developmental stage, consumed more food beginning at earlier stages, and were captured much later into the summer than fry captured at a spawning site in Lake Champlain. The lack of potential egg and fry predators in Yellowstone Lake could be driving these differences in spawning site selection and fry behavior. This information will allow managers to identify additional spawning locations for suppression and evaluate the impact their efforts might have on the Lake Trout population in Yellowstone Lake.

Master of Science / Department of Geology / Matthew W. Totten / Sedimentary beds rich in volcanic ash have been reported throughout Kansas. It is believed the source of these ashes are the large-scale eruptions from the Yellowstone Calderas. Very few of these ash units have been dated, however, and the vast majority simply reported as “Pearlette Ash.” The objective of this research was to investigate the potential of trace element geochemistry in correlating individual ash outcrops in Kansas to their eruptive source. Thirty-six previously reported ash occurrences of unknown age in Kansas were reoccupied and sampled. In addition, three unreported ash deposits were discovered and sampled. Two ash units previously identified as Huckleberry Ridge-aged and three as Lava Creek B were also collected. The samples were processed using the method of Hanan and Totten (1998) to concentrate ash shards. These ash concentrates were analyzed for specific trace and rare earth element (REE) concentrations using inductively coupled mass-spectrometry (ICP-MS) at the University of Kansas. The ash samples from known eruptions have distinct trace and REE signatures, allowing comparison to the unknown ash units. Most of the unknown ash samples correlate with specific Yellowstone eruptions. The majority of the undifferentiated “Pearlette Ash” samples correlate with the most recent Lava Creek B eruption and several unknown ashes correlate to the Huckleberry Ridge eruption. The distribution of ash units in Kansas being dominated by Lava Creek (0.60 ma) is expected because it is the most recent of the Yellowstone eruptions. The abundance of the older Huckleberry Ridge (2.10 ma) over the more recent Mesa Falls (1.27 ma) is likely the result of the much larger Huckleberry Ridge eruption.

Fifty-nine female and six male little brown myotis (Myotis lucifugus) were radio-tagged during the summers of 2012, 2013, 2014, and 2015 in Yellowstone National Park. The grand models for daily maximum skin temperature (F98,154 = 1.55, P = 0.007), daily minimum skin temperature (F98,154 = 1.33, P = 0.05), and daily variation in skin temperature (F98,154 = 1.56, P = 0.006) were significant across roost type and reproductive condition class for adult females. Roosts were classified into Types A (warmest roosts), B (roosts with largest daily temperature variance), and C (stable and cool roosts) depending on differences in mean maximum, minimum, and variance in temperatures per day (P < 0.001). A total of 347 torpor bouts were recorded from 38 females across the 2012 to 2015 summer seasons. Bats across different reproductive classes and roost types used torpor at different hours of the day. My research suggests that adult female little brown myotis at high elevations in the Park extensively use and rely on building structures for roosting sites during the reproductive season, whereas males used primarily natural roosts.

A new apatite (U-Th)/He (AHe) dataset from subvertical transects collected in the Teton and Gallatin Ranges in the Teton-Yellowstone region provides insight for the slip history and length of the Teton fault. Along the northernmost segment of the Teton fault, inverse thermal history modeling of AHe data from Eagles Rest Peak yield a ~9 Ma age for onset of fault slip. This age supports previous interpretations that Mount Moran may be the true center of the Teton fault. This refined interpretation coupled with lengthdisplacement fault scaling analysis and previous estimates of total fault displacement (~6 km) indicates that the Teton fault may extend 50-90 km north of Mount Moran. However, this new data precludes the possibility that the Teton and East Gallatin faults represent the same structure. Yet, because these systems share a similar structure trend and initial slip ages (13 Ma and 16 Ma, respectively), they may still be related at a larger scale. To the south, the Teewinot transect yields the oldest onset age of ~32 Ma, however a >500 m vertical data gap in this transect leads us to cautiously interpret the results of this model, particularly as this age conflicts with four other transects along-strike.

Le geyser d'Old Faithful dans le Parc National de Yellowstone, aux États-Unis, est l'undes geysers les plus connus au monde. La cyclicité de ses éruptions est étudiée depuis lesannées 60 a_n de comprendre sa dynamique. En e_et, le caractère bimodal de la fréquencede ses éruptions intriguent les scienti_ques qui cherchent à en connaître les causes.Les enregistrements sismiques réalisés à la surface du geyser démontrent des signauximpulsionnels dont l'origine fut identi_ée par Sharon Kedar. Ainsi, en 1992, S. Kedar etses collègues ont déployé plusieurs capteurs sismiques dans le but d'étudier la source dessignaux sismiques de type tremor enregistrés à la surface du dôme. Ils ont ainsi identi_éla source du signal sismique enregistré à la surface du geyser comme étant des signauxde cavitation de bulles. La cavitation se produisant à la surface du niveau de l'eau dansle conduit, les localisations des sources sismiques réalisées à partir des enregistrements desurface peuvent être reliées au niveau de l'eau dans le conduit.Dans un premier temps nous avons proposé de localiser les sources sismiques desenregistrements à partir de la méthode du Matched Field Processing (MFP) provenantde l'acoustique sous-marine. Plusieurs algorithmes du MFP ont été testés pour pouvoirlocaliser au mieux les sources sismiques. La bonne concordance des résultats obtenus avecchacun des algorithmes a permis d'obtenir un grand nombre de localisations des sourcesau cours du cycle. Les positions déterminées avec les di_érents algorithmes du MFP ontpermis de mettre en évidence deux zones d'activité hydrothermale du geyser associéesà di_érentes périodes du cycle éruptif, telles que le remplissage du conduit avant leséruptions et l'alimentation du geyser en eau une fois la vidange du conduit e_ectuée.Dans un second temps, l'analyse des variations de vitesse des signaux sismiques estproposée pour suivre des changements des propriétés du dôme du geyser, comme des variationsde pression avant l'éruption. Pour cela, une nouvelle méthode basée sur les mesuresde phases instantanées est suggérée. Les résultats obtenus montrent des faibles changementsde vitesse, pouvant être associés à la mise en pression du dôme ou à l'augmentationde la température du milieu avant l'éruption en surface.

This dissertation analyzes the spatial distribution and kinematics of the Late Cenozoic Basin and Range (BR) and cross normal fault (CF) systems and their related graben basins around the Snake River Plain (SRP), and investigates the spatio-temporal patterns of lavas that were erupted by the migrating Yellowstone hotspot along the SRP, applying a diverse set of GIS-based spatial statistical techniques. The spatial distribution patterns of the normal fault systems, revealed by the Ripley's K-function, display clustered patterns that correlate with a high linear density, maximum azimuthal variation, and high box-counting fractal dimensions of the fault traces. The extension direction for normal faulting is determined along the major axis of the fractal dimension anisotropy ellipse measured by the modified Cantor dust method and the minor axis of the autocorrelation anisotropy ellipse measured by Ordinary Kriging, and across the linear directional mean (LDM) of the fault traces. Trajectories of the LDMs for the cross faults around each caldera define asymmetric sub-parabolic patterns similar to the reported parabolic distribution of the epicenters, and indicate sub-elliptical extension about each caldera that may mark the shape of hotspot’s thermal doming that formed each generation of cross faults. The decrease in the spatial density of the CFs as a function of distance from the axis of the track of the hotspot (SRP) also suggests the role of the hotspot for the formation of the cross faults. The parallelism of the trend of the exposures of the graben filling Sixmile Creek Formation with the LDM of their bounding cross faults indicates that the grabens were filled during or after the CF event. The global and local Moran’s I analyses of Neogene lava in each caldera along the SRP reveal a higher spatial autocorrelation and clustering of rhyolitic lava than the coeval basaltic lava in the same caldera. The alignment of the major axis of the standard deviational ellipses of lavas with the trend of the eastern SRP, and the successive spatial overlap of older lavas by progressively younger mafic lava, indicate the migration of the centers of eruption as the hotspot moved to the northeast.