Geochemistry Commons^™

Experimental Insights Into The Origin Of Microcrystalline Calcites, Mohammed Hashim

Dissertations

A significant proportion of modern marine calcium carbonate sediments is dominated by metastable aragonite and high Mg calcite that either dissolves or stabilizes to low-Mg-calcite (calcite) or dolomite during diagenesis. Sediment dissolution and stabilization have implications for the CaCO3 budget in the ocean and carbon burial rates. Yet, the diagenetic conditions that promote each process and their relative importance are poorly understood. Further, stabilization most commonly produces calcite microcrystals that exhibit various textures and host micropores. Despite their ubiquity in the rock record, the controls on microcrystal textures remain unclear. Here, laboratory experiments were used to investigate aragonite-to-calcite stabilization as …

The Mineralogy And Geochemistry Of Illinois Basin Paleosols: Recognizing Detrital, Pedogenic, And Diagenetic Minerals, Julia A. Mcintosh

Earth Sciences Theses and Dissertations

The geochemical compositions of minerals in paleosols are assumed to be homogenous and attained through chemical weathering processes during episodes of pedogenesis in the geologic past. As such, the geochemical composition of minerals from paleosols may be used to reconstruct ancient climates and environments. One problem with this assumption is that paleosols were initially clastic sedimentary rocks or substrate prior to pedogenesis, thus it is likely that some portion of the paleosol is still composed of detrital minerals. Secondly, conditions may change in a sedimentary basin as the basin is buried and later uplifted, potentially triggering new mineralization or transformation …

Empirical And Modeled Δ13c And Δ15n Isoscapes In The Gulf Of Mexico And Their Application To Fish Eye Lens Migration Studies, Brianna Michaud

USF Tampa Graduate Theses and Dissertations

Isoscapes are depictions of the spatial patterns of isotopic values in a given area. Isoscapes can be created using measurements form samples (empirical isoscapes) or using statistical models of spatial isotopic variation (modeled isoscapes). Isoscapes have a wide variety of potential applications though, in the realm of marine ecology, they are most often used infer ecological processes, food web linkages, the origin of samples, and the movements of marine organisms.

However, to use isoscapes for these applications, it is necessary to have isoscapes at spatial scales relevant to the application in question. It is also necessary to have isoscapes that …

Augmenting Field Nuclear Forensics Capabilities With Handheld Atomic Spectroscopy Devices For Nuclear Debris Analysis, Ashwin P. Rao, Christopher M. Sutphin, Christina L. Dugan

Faculty Publications

The realm of technical nuclear forensics remains a critical part of joint counterproliferation capabilities. Since the passage of the Nuclear Forensics and Attribution Act (H.R.730) in 2010, the nuclear science community has undertaken steps to bolster national nuclear forensics capabilities under the National Technical Nuclear Forensics Center. Within the technical nuclear forensics umbrella, one particular area of interest involves developing capabilities for in-field analysis of nuclear material. This includes engaging in field training exercises across relevant branches of the military and investigating new technologies to conduct field nuclear forensic analyses. The integration of novel analytical technologies into real-world nuclear detection …

Contrasting Styles Of Inter-Caldera Volcanism In A Peralkaline System: Case Studies From Pantelleria (Sicily Channel, Italy), Pierangelo Romano, John C. White, Silvio G. Rotolo, Nina J. Jordan, Rosolino Cirrincione, Giovanni De Giorgio, Patrizia Fiannacca, Epifanio Vaccaro

EKU Faculty and Staff Scholarship

The recent (<190 ka) volcanic history of Pantelleria is characterized by the eruption of nine peralkaline ignimbrites, ranging in composition from comenditic trachyte to comendite to pantellerite. The ~46 ka Green Tuff (GT) was the last of these ignimbrites, which was followed by many effusive and explosive low-volume eruptions of pantellerite from vents within the caldera moat and along the caldera rim. Although recent studies have shed additional light on the age, petrochemistry, and volcanology of the older ignimbrites, there is very little knowledge of magmatism that occurred between these older ignimbrites, primarily due to the very scarce exposures. In this paper, we present new field descriptions and geochemical data for three local peralkaline centers never studied before, two pre-GT and one post-GT, which share a similar setting with respect to the caldera scarps but differ in terms of their age, composition, and eruptive style. These centers include: (i) the older (~125 ka) Giache center (comenditic trachyte), (ii) the ~67 ka Attalora center (comendite, pantellerite), and (iii) the younger (~14 ka) Patite center (pantellerite).

Stratigraphic And Geochemical Evaluation Of Distal Flows Of The Columbia River Flood Basalts In The Greater Vale Area, Southeastern Oregon, Lena Marie Fox

Dissertations and Theses

Exposures of Columbia River Basalt Group (CRBG) in southeastern Oregon are dominated by the four main phase CRBG units: Steens Basalt, Imnaha Basalt, Grande Ronde Basalt (GRB), and Picture Gorge Basalt (PGB). These units are best seen in stratigraphic sequence along the Malheur Gorge corridor of southeastern Oregon, between the towns of Vale and Juntura, with flows of Steens Basalt from the south overlain by flows of Imnaha and GRB from the north. Recently, PGB flows were found to be part of the eastern Malheur Gorge stratigraphy as well.

In Malheur Gorge, local units of Birch and Hunter Creek Basalt …

Geologic Homogenization, Conditioning, & Reuse, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about the Energy & Environmental Research Center project to evaluate the geologic homogenization, conditioning, and reuse (GHCR) concept of water management. Describes the GHCR concept and summarizes results of the multiyear project.

Exceptional Agate Formation Found In Spokane Basalt, Matthew J. Markus

2022 Symposium

People don’t normally associate semi-precious gems with basalt or the “boring black rock” that dominates the Eastern Washington landscape. However, a site just northeast of Cheney in the West Planes of Spokane, shows where a system of gem-filled veins can be found nestled into the 16-million-year-old (Kasbohm and Schoene, 2018) Priest Rapids Member of the Wanapum Basalt that is a part of the greater Columbia River Basalt. The volcanic rocks are the host to millimeter - 10 cm wide fractures with variable colored agate and opal.

Evaluating Holocene Precipitation Variability In The Baltic Region Using Oxygen Isotopes Of Lacustrine Carbonate From Estonia, Maxwell Gordon Boes

Graduate Research Theses & Dissertations

A high-resolution Holocene record of groundwater isotopic composition from eastern Europe enhances the current understanding of ocean atmosphere interactions and moisture transport dynamics. In the modern system, it has been established that the amount of regional winter precipitation is driven by the strength and direction of the sea level atmospheric pressure gradient over the Atlantic Ocean. This is defined by the North Atlantic Oscillation (NAO) index, that shows a positive correlation with precipitation amount during the cold season. This study aims to discover the link between atmospheric dynamics and the ratio of warm season to cold season precipitation through the …

Spatial Geochemical Changes In Central And East Texas Soils Over Time Resulting From Human Decomposition, Isabela Marisol Overturf

CMC Senior Theses

Human decomposition is studied to aid forensic investigations and better understand the impact of cemeteries on urban resources like soil and groundwater. The purpose of this study was to identify changes in soil geochemistry at and around a human grave to search for lateral nutrient movement and possibly identify new patterns in elemental concentrations that could be used in estimating post-mortem intervals (PMIs). At the Forensic Anthropology Research Facility (FARF) at Texas State San Marcos, soil samples were collected from a shallow grave over the course of 54 days to conduct analysis for organic matter content, texture, pH, and bulk …

Chemical Characterization Of Clastic Cave Sediments And Insights Into Particle Transport And Storage In Karst Aquifers, Jill L. Riddell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Abstract

Chemical characterization of clastic cave sediments and insights into particle transport and storage in karst aquifers

Jill L. Riddell

Cave sediments can be divided into two groups: precipitates and clastics. Precipitates are speleothems, or lithologic or mineral features that are chemically precipitated in the cave environment. Clastic cave sediments are frequently described by depositional facies, sorting, and particle size (Bosch and White, 2004). Robust analytical chemical analyses of these sediments to quantify their physical and chemical components is rarely performed although some chemical characterization of mineralogy and paleomagnetism has become prevalent in recent years (Chess et al., 2010; Sasowsky …

U-Pb Apatite Chronometry Of Intrusions In An Accretionary Metamorphic Belt In Western Idaho, Usa, Colleen Grace Rankin

Graduate Theses/Dissertations

The Salmon River suture zone in west-central Idaho, USA records the tectonic processes where island arcs, similar to modern-day Japan, were accreted to the North American continent in the Jurassic and Cretaceous periods (160-90 million years ago). This suture zone contains metamorphic rocks that were buried deep within the crust at depths of 20 kilometers or more and have subsequently been brought to the surface. The exhuming processes responsible for the metamorphic rocks in the Salmon River suture zone remains unclear. Two competing hypotheses have been proposed to explain the transport of the rocks from the Salmon River suture zone …

Stable Isotope Analysis Of A Platecarpus Tympaniticus (Squamata, Mosasauridae) With Actinocamax Sternbergi (Mollsuca, Belemnoidea) Reveals Possible Endothermic Thermoregulation, Mitchell Lukens

Master's Theses or Doctor of Nursing Practice

Mosasaurs, ancient marine reptiles, dominated the late Cretaceous oceans. However, their ecological success is a contentious topic. Were they ectothermic, like their modern relatives the varanid lizards? Or endothermic like extant marine mammals? Stable isotopes can reveal temperature and physiological variances within skeletons, but do not differentiate between body temperature and ambient environmental temperature. A rare mosasaur specimen from the Smoky Hill Chalk of a partial, articulated Platecarpus tympaniticus with stomach contents of belemnites provides a possible direct temperature contrast between predator and prey. The belemnites, related to modern coleoids, are identified as Actinocamax sternbergi. These animals possessed body …

Using Geochemical Composition To Determine Paleo Environmental Conditions And Source Inputs In Paleozoic Rocks Within The Central Kansas Uplift Usa, Christiana Fumnanya Eziashi

Master's Theses or Doctor of Nursing Practice

Paleoenvironmental conditions, sediment characteristics and lateral continuity using chemostratigraphy are not well established for stratigraphic units associated with some small fields within the Central Kansas Uplift (CKU). Samples of drill cuttings recovered from six wells (Hottman #1, and Hottman-Furthmeyer#1, Yocemento #1, Mong Benno #2, Rhian #3 and Worcester #1) at 10 ft intervals between 3150 ft and 3900 ft below ground level, were processed and analyzed using X-ray fluorescence (XRF) and X-Ray diffraction (XRD). The XRF technique was used to determine elemental compositions, and XRD was used to determine mineral content. The composition of the rock cuttings was used to …

Validation Of The Use Of Clathromorphum Compactum Growth And Skeletal Δ18o As A Proxy For Seawater Conditions, Teagan Mcmahon

Pitzer Senior Theses

Crustose coralline algae (CCA) are important organisms that create benthic habitat in the photic zone of oceans worldwide. CCAs mechanisms of photosynthesis and calcification may, in some cases, make them vulnerable to climate change and ocean acidification. Therefore, CCA are important not only for their ecological role within ecosystems but also for their ability to indicate the effects that ocean acidification and climate change may have on other marine calcifying organisms. Some species of CCA are known to be useful recorders of paleo oceanic conditions. These climate archives and reconstructions of past environmental conditions are important for understanding past changes …

Distribution Of Particulate Organic Carbon – Fluxes And Inventories – In Growth-Faulted Coastal Wetlands, Samuel Joel Whitehead

Theses and Dissertations--Earth and Environmental Sciences

Coastal wetlands along the Northern Gulf of Mexico (NGOMx) are critically important but threatened environments which provide significant and diverse economic, social, and environmental value. These environments are essential components to the global carbon cycle, serving as one of the most efficient terrestrial carbon sinks. Since onset of the Industrial Revolution increasing rates of coastal wetland loss have been documented due to a variety of anthropogenic activities, neotectonic processes, subsidence, and rising sea-levels. This research utilized an array of methods and sedimentological analyses to test the hypothesis that growth-fault induced changes at Earth’s surface affects the delivery to, and storage …

Defining The Endmember System Of Us Soils And Quantifying Relationships, And A Hyperspectral Approach To The Alteration Strength Index, Rachel Rulison

Dissertations, Master's Theses and Master's Reports

Soils form a complex part of the environment, providing important functions in systems such as food production, groundwater movement, and ecosystem health. There have been numerous studies on soil geochemistry and the origin of elements within soils, but few studies into quantifying the relationships between elements and geographical data on a national scale. Using geochemical data obtained by the USGS, the surficial soils of the US were defined by a 13-endmember system using Polytopic Vector Analysis and mapped in GIS. Correlation matrices provided Pearson’s correlation coefficients for elements in the Top 5 cm soil profile, the A horizon, and the …

The Effects Of Channel Incision And Land Use On Surface-Water/Groundwater Interactions In The Teanaway River Basin, Washington, Usa, Joseph Petralia

All Master's Theses

The Teanaway River basin, a major tributary to the Yakima River, is host to several restoration projects with the intention of returning the river channel to a more natural state and improving riparian habitat. These projects may also increase aquifer storage and potentially increase summertime streamflows. This study of the Teanaway Valley Family Farm, an 88-hectare parcel on the main-stem Teanaway River that was recently purchased by Washington Department of Fish and Wildlife, provides hydrogeologic data that will inform these restoration projects. Following the purchase of this land, ten wells were installed within and slightly above the floodplain in order …

Structural And Petrologic Insights Into The Emplacement Of Effusive Silicic Lavas: Inyo Domes, California, Shelby L. Isom

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Long Valley volcanic region, eastern California, USA is most famous for the caldera-forming eruption which produced the Bishop Tuff ~760,000 years ago. Over the last 3,000 years volcanism has been focused in the western margin of the region through punctuated eruptions of silicic lavas and domes. Three simultaneous effusive silicic eruptions, ~600 years ago, generated three lava domes: Obsidian Dome; Glass Creek Dome; and Deadman Dome which erupted onto vastly different topographies. These domes are exceptionally unique as they erupted variable amounts of two textural and chemical endmember lavas (crystal-rich and crystal-poor) that intimately mixed. The overarching goal of …

Pascoite Minerals And Potential Application Of Nmr Spectroscopy, Craig C. Mclauchlan, Beth Trent-Ringer, Debbie C. Crans

Faculty Publications – Chemistry

The 20 minerals encompassing the pascoite family of decavanadate isopolyanion-containing [V₁₀O₂₈]⁶⁻ minerals include a few minerals, such as rakovanite, that have been described as containing a protonated decavanadate anion. Rakovanite was originally assigned the formula Na₃[H₃V₁₀O₂₈]•15H₂O and now is redefined with an ideal formula (NH₄)₃Na₃[V₁₀O₂₈]•12H₂O. Nuclear magnetic resonance (NMR) and particularly ⁵¹V NMR spectroscopy is an informative method used to describe the protonation state and speciation in both solid and solution states …