Digital Commons Network^™

Geothermal Regime Of The Williston Basin In North Dakota, Faye N. Ricker

Theses and Dissertations

Understanding the thermal regime of a large intracontinental basin such as the Williston Basin can be enhanced by analysis of the relationships among radiogenic heat production, surface heat flow, formation temperatures, and gravity and magnetic anomaly patterns. Digital processing of the spatial and causal relationships gives insight into the effect of basement heat production on the thermal state of the basement rocks and the overlying sedimentary successions. These relationships provide valuable insight on the radioactive heat contribution to heat flow, heat flow from the lower crust, composition of the upper crust, and the potential for geothermal power generation. The specific …

Global Trends In Extreme Precipitation: Climate Models Versus Observations, Behzad Asadieh, Nir Y. Krakauer

Publications and Research

Precipitation events are expected to become substantially more intense under global warming, but few global comparisons of observations and climate model simulations are available to constrain predictions of future changes in precipitation extremes. We present a systematic global-scale comparison of changes in historical (1901–2010) annual-maximum daily precipitation between station observations (compiled in HadEX2) and the suite of global climate models contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We use both parametric and non-parametric methods to quantify the strength of trends in extreme precipitation in observations and models, taking care to sample them spatially and temporally …

Wetchimp-Wsl: Intercomparison Of Wetland Methane Emissions Models Over West Siberia, T. J. Bohn, J. R. Melton, A. Ito, T. Kleinen, R. Spahni, B. D. Stocker, B. Zhang, X. Zhu, R. Schroeder, M. V. Glagolev, S. Maksyutov, V. Brovkin, G. Chen, S. N. Denisov, A. V. Eliseev, A. Gallego-Sala, K. C. Mcdonald, M. A. Rawlins, W. J. Riley, Z. M. Subin, H. Tian, Q. Zhuang, J. O. Kaplan

Publications and Research

Wetlands are the world’s largest natural source of methane, a powerful greenhouse gas. The strong sensitivity of methane emissions to environmental factors such as soil temperature and moisture has led to concerns about potential positive feedbacks to climate change. This risk is particularly relevant at high latitudes, which have experienced pronounced warming and where thawing permafrost could potentially liberate large amounts of labile carbon over the next 100 years. However, global models disagree as to the magnitude and spatial distribution of emissions, due to uncertainties in wetland area and emissions per unit area and a scarcity of in situ observations. …

Effect Of Rainfall Events On The Thermal And Moisture Exposure Of Underground Electric Cables, Andrew Fuhrmann

Graduate College Dissertations and Theses

Cable ampacity analysis is generally performed assuming constant worst-state environmental conditions, which often correspond to a dry soil condition or to a condition with uniform ambient soil moisture content. The characteristic time scale of thermal variation in the soil is large, on the order of several weeks, and is similar to the time scale between rainfall events in many geographic locations. Intermittent rainfall events introduce significant transient fluctuations that influence the thermal conditions and moisture content around a buried cable both by increasing thermal conductivity of the soil and by increasing the moisture exposure of the cable insulation. This paper …

Earthworm Presence In Northern Forests: Impact On Distribution Of Soil Carbon Within Aggregate Fractions, Meghan Elizabeth Knowles

Graduate College Dissertations and Theses

Growing concerns over climate change is driving research aimed at determining ways of retaining soil carbon (C) within managed northeastern forests. Earthworms are exotic to the state of Vermont and the current extent of earthworm community presence in the state's forests, as well as the long term impact these communities will have on soil C storage, is still unknown. Current research suggests that earthworms have conflicting effects on the C cycle of soils, simultaneously enhancing mineralization through soil mixing, while protecting C through the stabilization of microaggregate (mA) structures. The mA soil fraction represents a pool of physically stable structures …

Micro-Topological Effects On Redox-Sensitive Nutrient Availability Of Manganese, Iron, Sulfur, And Phosphorus, Lindsey C. Ruhl

Graduate College Dissertations and Theses

The working hypothesis for this study was that small elevation differences in field depressions affect the availability of redox active nutrients because the bottom of the depression remains waterlogged and in reducing conditions longer than the edge of the depression. Mn, Fe, S and P availabilities were investigated in a field depression with a 20 meter radius and 0.5 meter depth on a flood-prone, organic vegetable farm. One depression (Depression 1) was sampled seven times during three field seasons (May 2012-June 2014). The last two dates included sampling in an additional three depressions to allow a comparison among depressions on …

Using The Past As The Key To The Present: Informing Coastal Resource Management With Geologic Records, Benjamin D. Dejong

Graduate College Dissertations and Theses

Rising sea levels present an ongoing threat to communities and resources around the Chesapeake Bay, east coast, USA, where tide gauges indicate that the relative rise of sea level is approximately twice the rate of average, eustatic sea-level rise. This has significantly compromised the health and viability of salt marsh habitat on the Eastern Shore during the 20th century, and the biologists who are charged with managing coastal resources in the coming decades need to understand the nature and causes of high rates of regional sea-level rise to develop suitable adaptation plans.

Dated geologic deposits and geophysical models suggest that …

Sedimentologic Comparison Of The Late/Lower Early Middle Cambrian Altona Formation And The Lower Cambrian Monkton Formation, Ryan A. Brink

Graduate College Dissertations and Theses

The Altona Formation represents the oldest Cambrian sedimentary unit in northern New York, recording cyclic deposition in shallow marine and fluvial environments under both fair-weather and storm conditions. Five outcrops and one well log were measured and described at the centimeter scale and the top and bottom contacts of the Altona were identified. Based on the recognition of sedimentary structures such as hummocky cross stratification, oscillatory ripples, graded bedding, trough and tabular cross stratification, and bioturbation, as well as subtle lithologic changes, six lithofacies representing non-marine, middle to upper shoreface, offshore, and carbonate ramp environments were identified. The top contact …

The Interplay Between Deformation And Metamorphism During Strain Localization In The Lower Crust: Insights From Fiordland, New Zealand, Kathryn Elise Dianiska

Graduate College Dissertations and Theses

In this thesis, I present field, microstructural, and Electron Backscatter Diffraction (EBSD) analyses of rock fabrics from high strain zones in exposures of lower crustal Cretaceous plutons at Breaksea Entrance, Fiordland, New Zealand. The interplay between deformation and metamorphism occurs across multiple scales at the root of a continental arc. I show a series of steps in which retrogressive metamorphism is linked to the accommodation of deformation.

I define three main phases of deformation and metamorphism at Breaksea Entrance. The first phase (D1) involved emplacement of dioritic to gabbroic plutons at depths up to 60 km. The second phase (D2) …

Evaluation Of Key Geomechanical Aspects Of Shallow And Deep Geothermal Energy, Robert Alexander Caulk

Graduate College Dissertations and Theses

Geothermal energy has become a focal point of the renewable energy revolution. Both shallow and deep types of geothermal energy have the potential to offset carbon emissions, reduce energy costs, and stimulate the economy. Before widespread geothermal exploration and exploitation can occur, both shallow and deep technologies require improvement by theoretical and experimental investigations. This thesis investigated one aspect of both shallow and deep geothermal energy technologies. First, a group of shallow geothermal energy piles was modeled numerically. The model was constructed, calibrated, and validated using available data collected from full-scale in-situ experimental energy piles. Following calibration, the model was …

Biological Indicators Of Compost-Mediated Disease Suppression Against The Soilborne Plant Pathogen Rhizoctonia Solani, Lynn Fang

Graduate College Dissertations and Theses

Compost can suppress soilborne plant pathogens that cause significant damage on globally important food crops. However, reports of plant pathogen suppression are inconsistent likely because there are no established standards for feedstock material, application rate, and maturity age upon application. Excellent results can be achieved in greenhouse trials, but field applications are much less reliable. Disease suppression occurs through the activity of biocontrol organisms (direct antagonism), and general microbial competition. Biocontrol species are hypothesized to colonize the pile during the curing phase, but single species may not be as important as microbial consortia. Substrate composition during maturation may give rise …

An Evaluation Of Vermicompost As A Fast-Acting Nitrogen Amendment To Mitigate Nitrogen Deficiencies In Organic Vegetable Production, Peter Dalton Austin

Graduate College Dissertations and Theses

For sustained production, organic agriculture depends on plant needs being synchronized with the release of nutrients from organic amendments during decomposition within the soil. Because decomposition is strongly dependent on soil moisture and temperature, nutrient needs may not always be met as planned or synchronous with plant need. Unlike conventional agriculture, fast acting amendments are not readily available. Much of the evidence that vermicompost benefits crop production comes from studies on seed germination and production of starts in greenhouses. Yet, there is a dearth of information derived from field studies. Soil, soil and water nitrogen, plant development, and marketable yield …

Examination Of Geophysical Signatures Of Ethanol-Water Mixtures In A Homogeneous Sand Column Using Ground Penetrating Radar And Time-Domain Reflectometry, Angelo Lampousis, Neil Terry, Lee Slater

Publications and Research

In recent years there has been an increase in the frequency of incidents involving ethanol-blended gasoline affecting the groundwater. Near-surface geophysical methods hold promise for site characterization at ethanol contaminated sites. We attempted to record the broadband dielectric properties of ethanol at various concentrations as it was circulating through a closed tank containing either sand or a sand-clay mixture. Two high frequency GPR antennas were positioned symmetrically on either side of the sample holder to obtain transmission measurements. In the first part of the experiment we used a sample consisting of sand. In the second part of the experiment we …

The Effects Of Industrial Biomass Gasification Ash As A Soil Amendment On The Earthworm Eisenia Fetida, Michael J. Blackowicz

Masters Theses

Soil application of solid residues from thermal conversion of biomass (i.e. combustion and pyrolysis) has become a topic of interest in recent years. However, there exists a gap in the literature with regard to soil application of gasification residues and their effects on soil health and soil macroorganisms. This study investigates the effects of three different ashes (hardwood oak/hickory, hardwood willow, corn stover), collected from industrial biomass gasification reactors (University of Minnesota Morris, Eastern Illinois University), as a soil amendment on the composting worm Eisenia fetida. Additionally, ash samples were analyzed for total polycyclic aromatic hydrocarbons (PAHs) and potentially toxic …

Holocene Palynology Of The Gulf Of Papua, Papua New Guinea: Using Modern Palynomorph Distribution To Better Constrain Paleoenvironmental Changes, Marie Louise Thomas

LSU Doctoral Dissertations

Multiple NSF (National Science Foundation)-funded MARGINS Source-to-Sink cruises were conducted in the Gulf of Papua (GoP), Papua New Guinea (PNG), from 2003 through 2005 to better understand how sediment is created, transported, and deposited. Although much work has been done on the data collected during these cruises, palynological analysis has never been conducted on the hundreds of available cores. The first phase of this project (Chapters 2 and 3) examines the connection between modern depositional regimes in the GoP and species assemblages recovered. Statistical analysis of palynomaceral assemblages (Chapter 2) indicates a correlation between their distribution and bathymetry, sedimentation rate, …

Developing Recognition Criteria For Current-Wave-Enhanced Sediment Gravity Flows, Kathryn Christine Denommee

LSU Doctoral Dissertations

Sedimentary fabrics preserved in the rock record provide some of the best evidence for interpreting paleo-depositional conditions. Muddy sediments in particular are important paleoenvironmental archives, preserving the most complete stratigraphic record of any rock type in basinal settings. However, the full range of mechanisms responsible for the deposition of muddy sediments, particularly in high-energy settings, remains poorly understood. Although frequently observed in modern settings, muddy prodeltaic deposits are rarely identified in the rock record, in part because no catalogue of easily distinguishable recognition criteria exists for this class of mudstones. In order to help overcome this deficiency, this dissertation project …

Neodymium Isotope Ratios And A Positive Δ13c Excursion: Connecting Oceanographic And Climate Changes Near The M4-M5 Sequence Boundary Of The Late Ordovician, Zachary Wright

LSU Master's Theses

A significant positive carbon isotope excursion first described from the Guttenberg Member of the Decorah Formation in Iowa called the GICE is a defining feature of Late Ordovician chemostratigraphy. It occurs near the M4-M5 sequence boundary of the Late Ordovician and has been correlated across the globe using prominent K-bentonite ash beds and conodont biomarkers. The cause of the GICE has been debated, with some arguing that it represents the initiation of a glacial period in a greenhouse climate 10 Ma before the end Ordovician glaciation and extinction. A variety of cooling signals have been identified across the M4-M5 sequence …

Long-Term Litter Decomposition Controlled By Manganese Redox Cycling, Marco Keiluweit, Peter Nico, Mark E. Harmon, Jingdong Mao, Jennifer Pett-Ridge, Markus Kleber

Chemistry & Biochemistry Faculty Publications

Litter decomposition is a keystone ecosystem process impacting nutrient cycling and productivity, soil properties, and the terrestrial carbon (C) balance, but the factors regulating decomposition rate are still poorly understood. Traditional models assume that the rate is controlled by litter quality, relying on parameters such as lignin content as predictors. However, a strong correlation has been observed between the manganese (Mn) content of litter and decomposition rates across a variety of forest ecosystems. Here, we show that long-term litter decomposition in forest ecosystems is tightly coupled to Mn redox cycling. Over 7 years of litter decomposition, microbial transformation of litter …

Spectroscopic Characterization Of Oceanic Dissolved Organic Matter Isolated By Reverse Osmosis Coupled With Electrodialysis, John R. Helms, Jingdong Mao, Hongmei Chen, E. Michael Perdue, Nelson W. Green, Patrick G. Hatcher, Kenneth Mopper, Aron Stubbins

Chemistry & Biochemistry Faculty Publications

Oceanic dissolved organic matter (DOM) is one of the largest pools of reduced carbon on Earth, yet DOM remains poorly chemically characterized. Studies to determine the chemical nature of oceanic DOM have been impeded by the lack of efficient and non-fractioning methods to recover oceanic DOM. Here, a DOM fraction (~40 to 86% recovery) was isolated using reverse osmosis/electrodialysis (RO/ED) and analyzed by solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy. Samples were obtained from biogeochemically distinct environments: photobleached surface gyre, productive coastal upwelling zone, oxygen minimum, North Atlantic Deep Water, and North Pacific Deep Water. A ubiquitous ‘background’ refractory …

Paleomagnetic Determination Of Vertical-Axis Block Rotation And Magnetostratigraphy In The Mecca Hills And Coachella Valley, California, Cassidy W. (Cassidy Wade) Dimitroff

WWU Graduate School Collection

Our ongoing work on the paleomagnetism and magnetostratigraphy in the Coachella Valley has provided an improved understanding of the timing and spatial variations of sediment accumulation and deformation during evolution of plate-boundary fault zones. Here, we report updated results from the Palm Spring Formation of the Mecca Hills, and new paleomagnetic data from Pleistocene conglomeratic sandstone in Desert Hot Springs and the Plio-Pleistocene San Timoteo Formation from Live Oak Canyon.

From the Mecca Hills, new data were obtained-112 samples from 29 sites. The majority of the paleomagnetic results yielded well-defined components of magnetization, which allowed us to identify seven well …

Cockatoo Sands In The Victoria Highway And Carlton Hill Areas, East Kimberley: Baseline Surface Water Quality, Don Bennett, Luke Donovan, Duncan Palmer

Resource management technical reports

Cockatoo Sands are recognised as potentially suitable for irrigated agriculture because they are generally well drained and not subject to waterlogging and inundation. These characteristics allow them to be cultivated and prepared for planting of various crops during the wet and dry seasons of northern Australia.

Differential Incision And Uplift Of The Yakima River Terraces, Adrian M. Bender

WWU Graduate School Collection

The Yakima fold belt comprises fault-related folds deforming Miocene basalts and younger deposits of the Columbia Plateau in central Washington State. Geodesy implies ~2 mm/yr of modern, NNE-directed regional shortening; however the distribution of Quaternary deformation among individual structures remains unclear. South of Ellensburg, Washington, the Yakima River cuts a ~600-m deep canyon across several of the folds, preserving flights of strath terraces that record the progressive incision. Graded alluvial basins at the head and mouth of the canyon imply that terrace incision also records differential rock uplift. We integrate lidar analysis, field observations, and cosmogenic burial dating of eight …

High-Sr Volcanic Domes From The Lassen Volcanic Region, Southernmost Cascade Arc, Northern California: Implications For Andesite And Dacite Magma Generation, Christina M. Stout

WWU Graduate School Collection

The Onion Butte (OB) and Barkley Mountain (BM) groups are two lineaments of volcanic domes and lava flows located with the Lassen segment of the southernmost Cascades, northern California. The OB group (_~2.5 Ma) consists of 13 domes that are dominantly dacitic, but span the range from andesite to dacite. The BM group (_~1.5 Ma) comprises 21 domes that range from basaltic andesite to andesite, but are mostly andesitic.

The lavas of both groups are petrographically similar, but differ geochemically. The lavas are fine-grained, sparsely phyric containing needle-like hornblende phenocrysts, but lack the large plagioclase phenocrysts …

High-Mg Andesites From The Northern Cascade Arc: Using Mineral Chemistry To Distinguish Between Hypotheses For Petrogenesis, May Sas

WWU Graduate School Collection

A fundamental question in the Earth Sciences is whether, in certain situations, subducting lithospheric plates can get hot enough to generate melt that consequently contributes to magmatic output in volcanic arcs. Because the subducting plate beneath the Cascade arc is relatively young, and therefore understood to be hotter than older subducting slabs, slab melt generation is considered possible. Recent work has shown that slab melt is involved in magma petrogenesis in the southern Cascade arc (Walowski et al., 2015). To better understand the role of slab melt in north Cascades magmas, this study focused on petrogenesis of high-Mg lavas from …

Three-Dimensional Geologic Model Of The Pecatonica Gas Storage Field, Winnebago County, Illinois, Nicole Kron, David Malone, Eric Peterson

Eric Wade Peterson

Nitrates In Karst Systems: Comparing Impacted Systems To A Relatively Unimpacted System, Julie C. Angel, Eric Wade Peterson

Eric Wade Peterson

Karst aquifers are highly susceptible to contamination because of the connection with surface water. Nitrate contamination is common; with most karst aquifers exhibiting some degree of impact. This work assesses the potential impacts of anthropogenic activities on the Horn Hollow Valley (HHV) in Carter County Kentucky. HHV is a karst aquifer system that appears to be minimally impacted by nitrate and chloride contamination. Sampling of the HHV area was conducted from June 2005 to November 2006. Nitrate as nitrogen (NO3-N) concentrations were between 0.13 to 1.54 mg/L; chloride concentrations ranged from 1.43 to 66.3 mg/L. Impact from anthropogenic sources are …

Rock Strength Along A Fluvial Transect Of The Colorado Plateau - Quantifying A Fundamental Control On Geomorphology, Natalie Bursztyn, Joel Pederson

Natalie Bursztyn

Bedrock strength is a key parameter that influences slope stability, landscape erosion, and fluvial incision. Yet, it is often ignored or indirectly constrained in studies of landscape evolution, as with the K erodibility parameter in stream-power models. Empirical datasets of rock strength suited to address geomorphic questions are rare, in part because of the difficulty in measuring those rocks at Earth's surface that are heterolithic, weak, or poorly exposed. Here we present a large dataset of measured bedrock strength organized by rock units exposed along the length of the trunk Green–Colorado River through the iconic Colorado Plateau of the western …