Earth Sciences Commons^™

Understanding The Food Water Nexus: Characterizing The Impact Of Climatological Anomalies On Agrosystems, Patrick M. Wurster Jr.

Graduate Student Theses, Dissertations, & Professional Papers

Climate variability at global and regional scales is escalating with increased atmospheric carbon and is expected to magnify the intensity and duration of meteorological extremes, especially droughts. From the many environmental stresses that diminish crop production (e.g., soil salinity, frost, soil erosion) drought is one of the most prevalent. This study focuses on the sensitivity of three key crops produced in the northwestern United States to climatological anomalies, while controlling for attribution using anomalies in price. The study differs from similar studies in that we focus on variability in production which captures both yield (tonnes/ha) and cropping area (ha), as …

Estimating Groundwater Inflow And Age Characteristics In An Alluvial Aquifer Along The Little Wind River, Wyoming, Derek Goble

Graduate Student Theses, Dissertations, & Professional Papers

We synoptically sampled a 2 km gaining reach of the Little Wind River in central Wyoming for ²²²Rn, CFCs and SF₆ to determine the distributed volumes and locations of discharge and estimate alluvial groundwater age characteristics. ²²²Rn was sampled in the stream, shallow in-stream piezometers and nearby alluvial groundwater wells to determine the volume and spatial distribution of groundwater discharge to the river. Age tracers, CFC and SF_6, sampled in the stream, shallow in-stream piezometers and in alluvial groundwater wells were then used to determine whether in-stream samples are capable of constraining the residence time distribution …

Photochemical Cycling Of Reactive Oxygen Species In Hydrothermal Systems: Impacts On Biosignature Preservation, Megan A. Mave

Graduate Student Theses, Dissertations, & Professional Papers

Life originated on early Earth, despite harsh, highly reducing conditions. Life may have also emerged on early Mars, when conditions on the two planets were similar (i.e. before atmosphere loss and desiccation). NASA’s 2020 Mars rover mission aims to identify biosignatures (i.e. evidence of life) in early Martian deposits. Potential exploration sites include extinct hydrothermal springs, due to their high habitability and preservation potential. This study aims to better understand biosignature preservation in hydrothermal systems analogous to those on early Mars (i.e. reducing and Fe-rich).

Reactive oxygen species (ROS) are highly reactive molecules formed primarily by photochemical reactions. ROS are …

Facies Architecture And Controls On Reservoir Behavior In The Turonian Wall Creek Member Of The Frontier Formation, Powder River Basin, Wyoming, Nathan M. La Fontaine

Graduate Student Theses, Dissertations, & Professional Papers

Inter-well heterogeneities influencing fluid migration in deltaic reservoirs are controlled by lateral lithofacies changes and vertical complexities such as low permeability thin-beds. Subsurface tools often cannot predict the spatial and stratigraphic organization of these architectural elements, nor their influence on effective reservoir properties and connectivity. This study integrates sedimentological, stratigraphic, and fluid simulation data to 1) document the facies architecture and depositional evolution of the Turonian Wall Creek Member (WCM) of the Frontier Formation, and 2) quantify the role of multi-scale stratigraphic heterogeneity on reservoir behavior. Upscaled permeability properties derived from fluid simulation of nested, small-scale facies models condition the …

Impacts Of Vegetation Growth On Reach-Scale Flood Hydraulics In A Sand-Bed River And The Implications For Vegetation-Morphology Coevolution, Samuel Box

Graduate Student Theses, Dissertations, & Professional Papers

Vegetation affects river morphology via plant effects on the flow field, sediment transport and deposition, and substrate erodibility. Changes in the flow field caused by above-ground biomass mediate geomorphic response to flooding and habitat suitability for vegetation growth. Using numerical hydraulic models that incorporate drag due to spatially heterogeneous vegetation, I quantify how changes in the antecedent characteristics of woody vegetation in the active channel lead to changes in local bed shear stress, reach-average bed shear stress, and the vegetative component of reach-average total shear stress. Flood hydraulics in turn affect channel morphology and vegetation, providing a feedback mechanism by …

Watered Down: The Challenges Of Managing Water Resources In Montana, Beau E. Baker

Graduate Student Theses, Dissertations, & Professional Papers

Like much of the American West, Montana sits in the cross hairs of climate change. State drought resiliency projects and cooperative watershed management are on the rise in the face of decreased snowpack, early runoff, precipitation variability and lower seasonal stream flows. Population growth, land use practices, recreation and tourism all contribute to pressures on state water supplies.

Montana is faced with the arrival of invasive species that threaten the ecological health of its lakes, rivers and streams. State budget constraints and depressed agency capacity are hurting our ability to fend off these threats. There’s a lack of public education …

Insights Into The Proterozoic To Cretaceous Evolution Of The Western Clearwater Metamorphic Core Complex, Northern Idaho, Through Petrologic And Geochronologic Analysis, Nora Dwyer

Graduate Student Theses, Dissertations, & Professional Papers

The Clearwater metamorphic core complex (CMCC) in northern Idaho contains a rare exposure of the contact of the basal section of the Mesoproterozoic Belt Supergroup with underlying Paleoproterozoic basement. Prior to this study, this contact had not been well documented. In addition, the rocks within the CMCC preserve a complex history of metamorphism, including both Mesoproterozoic and Cretaceous-Eocene regional events. Detrital zircon analysis of five coarsely recrystallized, clean quartzite samples at this contact reveal a bimodal age distribution with peaks at around 1800 - 1900 Ma and 2650 Ma. Several grains are younger than 1700 Ma, with the youngest being …

Using Multiple Environmental Tracers To Investigate The Relative Role Of Soil And Deep Groundwater In Stream Water Generation For A Snow-Dominated Headwater Catchment, Isabellah V. Von Trapp

Graduate Student Theses, Dissertations, & Professional Papers

In this study, seasonal fluctuation of environmental tracers in stream flow, soil water, and deep bedrock groundwater were used to constrain the role of deep bedrock groundwater in streamflow generation for a mountainous headwater catchment. Synoptic measurements of stream discharge, ²²²Rn, specific conductivity and major ion concentrations were measured throughout the water year over a 5 km reach of Cap Wallace Creek in the Lubrecht Experimental Forest, Montana, U.S.A. with the intention of understanding groundwater – surface water interactions across spatial and temporal scales. Stage measurements were continually recorded at seven stilling well locations along the reach. Discharge measurements …