Geochemistry Commons^™

Geochemistry Of The Lazufre Volcanic Complex: Determining The Geometries And Processes Of The Magmatic Sources In The Central Andean Volcanic Zone, Brooke Erin Benz

Graduate Theses/Dissertations

The Central Andes in South America contain many active volcanoes and volcano complexes due to constant subduction producing extrusive rocks varying in composition. The Lazufre Complex, Chile-Argentina border, consists of two Pleistocene volcanic centers, Lastarria and Cordon del Azufre andesite and dacite lava flows and domes. Whole-rock K-Ar dates of lavas from Cordon del Azufre place the most recent eruptions at 0.6-0.3 Ma ±0.3 Ma. Major-element data of plagioclase and pyroxene show homogeneous compositions between the centers, which is consistent with whole rock major- and trace-element compositions. The primary composition of the pyroxenes are augite and diopsides for cpx and …

Geochemical Tracers Of Arctic Ocean Processes: A Study Of Gallium, Barium, And Vanadium, Laura M. Whitmore

Dissertations

The Arctic Ocean is linked to the global oceans and climate through its connectivity with the North Atlantic Ocean and the regional thermohaline deep water formation sites. It’s also a region undergoing rapid environmental change. To inform the community of potential changes in geochemical and biogeochemical cycles, this dissertation addresses three dissolved geochemical tracers (gallium, barium, and vanadium) as indicators of Arctic Ocean processes. Gallium is tested as a replacement for nutrient-type tracers in an effort to deconvolve Pacific and Atlantic derived waters in the Arctic Ocean basins. These water masses carry different heat and salt content and can influence …

Assessment Of Various Groundwater Recharge Methods In The Lower Kelantan River Basin, Malaysia, Hussin Nur Hayati

Student Works (2020-2029)

Groundwater recharge is a natural process to replenish the aquifer system. Since 1930s the groundwater demand has risen as it has supported 70% of water supply in Lower Kelantan River Basin. However, a comprehensive study on groundwater recharge mechanism has never been reported. This study evaluated various methods to identify recharge flow processes using stable isotopes of deuterium (2H) and oxygen-18 (18O), tritium (3H), radon (222Rn) and hydrogeochemical (HC) and quantify recharge rate using chloride mass balance (CMB), water table fluctuation (WTF), temperature-depth profile (TDP) and groundwater modelling coupled with water balance GM(WB) followed by the construction of a conceptual …

Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn

Graduate Theses/Dissertations

Lascar volcano is one the most active volcano in the Central Volcanic Zone of the Andean Cordillera, with 36 Holocene eruptions including a VEI 4 eruption in April 1993. Activity has not been consistent throughout time, and therefore, the processes behind it are poorly understood. Lascar volcano has cyclic behavior and has had four stages of activity, each of which had a unique eruptive style and product composition. Stage I (<43 >ka) had primarily mafic andesite lavas erupted effusively from a stratocone. Stage II initiated with dome building events ESE of the original vent and culminated in the 26.45 ka …

An Isotopic Assessment Of Late Prehistoric Interregional Warfare In The Southcentral Us, John R. Samuelsen

Graduate Theses and Dissertations

Skull burials are found all over the world. The cause of such ancient Native Americans deposits often lead to disagreement among scholars torn between warfare and ancestor veneration. One skull-and-mandible deposit, representing at least 352 people (A.D. 1253-1399), was uncovered at the Crenshaw site, a multiple-mound Caddo ceremonial center in southwest Arkansas. Most previous research suggested they were victims of interregional warfare from the Southern Plains or Mississippi Valley. One previous study hypothesized that this was a Caddo burial practice which expanded during the Middle Caddo period (A.D. 1200-1500) due to the adoption of maize as a staple and a …

Analysis Of Cryptotephra At Whitney Mesa Nature Preserve, Henderson, Nevada, Alex Newsom

Calvert Undergraduate Research Awards

Advanced Undergraduate Winner

Cryptotephra (small volcanic shards ranging 20-80 microns in size) were discovered within Unit X of the Las Vegas Formation at Whitney Mesa Nature Preserve, Henderson, Nevada. Cryptotephra are deposited soon after a volcanic eruption and can be used as a dating tool to create narrow time constraints for surrounding sediments. Cryptotephra have many applications but are mainly useful as a dating tool. Their study has important implications for the understanding of the timing of palaeoclimatological and paleoenvironmental events as well as for archaeological studies to date important events in human history.

The Whitney Mesa cryptotephra were correlated …

Archaeological Feature Identification Through Geochemical Analysis Of Arctic Sediments From The Cape Krusenstern National Monument, Northwest Alaska, Patrick William Reed

Dissertations and Theses

Identification and interpretation of archaeological phenomena is typically based on visual cues and the physical presence of "something archaeological," such as a diagnostic artifact, landscape modification, or structural element. Yet many archaeological features, i.e. the discrete archaeological deposits related to past human behavior, lack clear indicators of human activity that provides clues to the feature's origin. At the Cape Krusenstern beach ridge complex, located in northwest Alaska, ambiguous features, that could be natural or anthropogenic (vegetation anomalies), or are of unknown cultural function (indeterminate), comprise 60% of the identified features at the complex. These ambiguous features represent a large gap …

Temporal Transport Dynamics Of The Amazon River Plume Revealed Using Radium Isotope Analysis, Elana J. Ames

Electronic Theses and Dissertations

The Amazon River is the largest river by discharge in the world. It carries terrestrial nutrients into the Western Tropical North Atlantic via a buoyant freshwater plume, conveying water hundreds to thousands of kilometers away and driving critical biogeochemical cycles near the coast. Factors controlling the delivery of nutrients offshore by the plume are complicated and interconnected, yet these nutrients impact the foundation of phytoplankton community structures across the entire plume ecosystem. To better understand the temporal dynamics of this massive, highly influential region, we employ naturally occurring radium isotopes (223Ra, 224Ra, 226Ra, and 228Ra) to analyze mixing and transport …

Quantifying Tekeze River Canyon Incision On The Ethiopian Plateau From Low-Temperature Apatite Thermochronology, Jacob Thomas Grigsby

Masters Theses & Specialist Projects

The Ethiopian Plateau in East Africa features dynamic topography, deep river incision (~1.5 km), active tectonics, continental rifting, volcanic terrain and ~2 km of plateau uplift. Situated on the northwestern part of the Ethiopian Plateau, the Tekeze River is one of the two major rivers associated with incising and documenting the recent geologic history of the uplifted plateau landscape. The consequential Tekeze River incision into the uplifted Ethiopian Plateau is associated with the arrival and impingement of the Afar mantle plume as evidenced by the presence of thick sheets of Cenozoic flood basalts (~30 Ma). However, the Cenozoic to present-day …

Geochemical Analyses Of Base Metals In Sediments And Stream Water Black Cypress Bayou, Marion County, Texas, Melanie L. Ertons

Undergraduate Research Conference

Black Cypress Bayou is a primary tributary of Caddo Lake watershed in eastern Texas. The watershed is underlain by Eocene-aged strata from the Wilcox and Claiborne groups, which represent transgressive/regressive shoreline fluctuations that deposited interbedded friable sandstones and mudstones. The Wilcox Group is of special interest because it contains lignite coal, which has a direct link to heavy metals in sediment and natural waters. Caddo Lake has been listed on the Texas Commission on Environmental Quality 303(d) list for impairment due to mercury in edible tissue since 1995 and Black Cypress Bayou has been listed for impaired waters due to …

Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre

Earth Sciences Theses and Dissertations

Volcanic eruptions can cause significant socioeconomic loss, but a better understanding of the processes and dynamics influencing the evolution of volcanic plumbing systems will advance the development of eruption forecasting models that will ultimately mitigate hazards and risks associated with eruptive events. Geologic and geophysical data must be integrated in 3D, finite- element, multiphysical, numerical models to define the coupled evolution of magmatic and crustal stress regimes in volcanic environments, but in data limited regions this is not always an option. The remote nature of the Aleutian Island Arc restricts ground-based monitoring and sampling efforts, and due to sparse temporal …

Fort Ancient And Woodland Pottery From The Hahn Site, Hamilton County, Ohio: A Petrographic Analysis Of Chronological Changes In Ceramic Temper, Shelby C. Lutz 20

Honor Scholar Theses

Thousands of pottery sherds have been excavated by the Cincinnati Museum Center from the Hahn Site (Ohio Archaeological Site #33HA10), located near Newtown, Ohio. These potsherds, created by Native Americans, show a variety of temper materials, including fragments of limestone, shell, grog, and rock debris from glacial outwash. To better understand changes in the pottery-making technique, transitions and advancements in temper material, and possible economic and trade indicators, ceramic petrography and geochemical analyses were used to determine temper variability. A single archaeological feature from the site was chosen as a case study, Feature 146. This feature is a depression that …

Element Transport In A River-Lake Continuum Across Forest-Dominated Landscapes: A Case Study In Central Louisiana, Zhen Xu

LSU Doctoral Dissertations

Studying the biogeochemical connectivity between rivers and lakes can help us understand their ecological and environmental impacts within a drainage basin, which is especially true for forest watersheds that play a vital role in provisioning freshwater services to ecosystems and downstream communities. This dissertation research consists of three interconnected studies with the overarching goal of discerning the connectivity of elements in a river-lake continuum across forest-dominated landscapes. These studies utilized water samples and in situ measurements collected from the Little River-Catahoula Lake continuum in the subtropical Louisiana, USA at monthly intervals during 2015-2016 and 1978-2008 historical water quality, hydrological and …

Groundwater Quality In The High Plains Aquifer

United States Geological Survey: Publications

Groundwater provides nearly 50 percent of the Nation’s drinking water. To help protect this vital resource, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project assesses groundwater quality in aquifers that are important sources of drinking water. The High Plains aquifer constitutes one of the important aquifers being evaluated.

The High Plains aquifer underlies an area of about 169,000 square miles, which is populated by about 2 million people in parts of eight western states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, South Dakota, and Wyoming). The aquifer ranks 13th in the Nation as a source of groundwater for …

Marine Carbonyl Sulfide (Ocs) And Carbon Disulfide (Cs2): A Compilation Of Measurements In Seawater And The Marine Boundary Layer, Sinikka T. Lennartz, Christa A. Marandino, Marc Von Hobe, Meinrat O. Andreae, Kazushi Aranami, Elliot Atlas, Max Berkelhammer, Heinz Bingemer, Dennis Booge, Gregory A. Cutter, Pau Cortes, Stefanie Kremser, Cliff S. Law, Andrew Marriner, Rafel Simó, Birgit Quack, Günther Uher, Huixiang Xie, Xiaobin Xu

OES Faculty Publications

Carbonyl sulfide (OCS) and carbon disulfide (CS₂) are volatile sulfur gases that are naturally formed in seawater and exchanged with the atmosphere. OCS is the most abundant sulfur gas in the atmosphere, and CS₂ is its most important precursor. They have attracted increased interest due to their direct (OCS) or indirect (CS₂ via oxidation to OCS) contribution to the stratospheric sulfate aerosol layer. Furthermore, OCS serves as a proxy to constrain terrestrial CO₂uptake by vegetation. Oceanic emissions of both gases contribute a major part to their atmospheric concentration. Here we present a database of …

Thermal Analysis, Compressibility, And Decomposition Of Synthetic Bastnäsite-(La) To Lanthanum Oxyfluoride, Richard L. Rowland, Barbara Lavina, Kathleen E. Vander Kadeen, Lisa R. Danielson, Pamela C. Burnely

Geoscience Faculty Research

Understanding basic material properties of rare earth element (REE) bearing minerals such as their phase stability and equations of state can assist in understanding how economically viable deposits might form. Bastnäsite is the most commonly mined REE bearing mineral. We synthesized the lanthanum-fluoride end member, bastnäsite-(La) (LaCO3F), and investigated its thermal behavior and decomposition products from 298 K to 1173 K under ambient pressure conditions through thermogravimetric analysis, differential scanning calorimetry, evolved gas analysis, and high temperature powder X-ray diffraction. We also investigated the compressibility of bastnäsite-(La) via single crystal X-ray diffraction in diamond anvil cells at an ambient temperature …

Active Growth Of Non-Hydrothermal Subaqueous And Subaerial Barite (Baso4) Speleothems In Lechuguilla Cave (New Mexico, Usa), Max Wisshak, Hazel A. Barton, Katey E. Bender, Harvey R. Duchene

International Journal of Speleology

Barite (BaSO₄) speleothems have been reported from caves around the globe and interpreted to have chiefly formed in phreatic, hypogene, hydrothermal settings. Here we report two contrasting types of barite speleothems (bluish tabular crystals in a shallow pool and actively dripping greenish stalactites), which today form at lower temperatures in the non-hydrothermal and vadose environment of Lechuguilla Cave, New Mexico, USA. Scanning electron microscopy analysis, along with energy- and wavelength-dispersive X-ray spectroscopy (EDS, WDS), as well as X-ray diffraction (XRD), characterize the habit and chemical composition as barite. Fractionation of the minor element calcium is related to growth …

Geochemical Response To Thermal Energy Storage In The Columbia River Basalt Aquifer System Beneath The Portland Basin, Oregon, Ellen Elizabeth Svadlenak

Dissertations and Theses

Deep direct use thermal energy storage (TES) is a low carbon emission method of geothermal energy storage and supply for large-scale residential, commercial, and manufacturing heating and cooling. The process entails repeated cycles of hot- or cold-water injection, storage, and extraction from slow groundwater flow zones within the deeper layers of an aquifer system. Though a promising technology, TES cycles may increase mineral dissolution and precipitation reactions, particularly at elevated temperatures. The ensuing mass transfer can form scale in heat exchange systems and alter aquifer porosity and permeability, processes that can reduce the operational efficiency of a TES system.

Within …

Geochemical Analysis And Heat-Treatment Of Natural Sapphires From Madagascar And Tanzania In Oxidizing And Reducing Conditions, Lukas Karuza, Dr. Michael B. Wolf, Brian Konecke Phd

Geology: Student Scholarship & Creative Works

Natural or synthetic sapphires can be heat-treated to improve the clarity by removing “silk” (inclusions) and to change color by introducing color-inducing elements (i.e., chromophores) into the lattice structure or changing their valency. Due to these reasons, sapphires can be heat-treated to increase their monetary value. Twenty natural blue (C1), 20 green (C2), and 20 clear (C3) sapphires from Madagascar and Tanzania were heat-treated in a muffle furnace in oxidizing and reducing conditions, from 1200 to 1600℃, for 10-hour soak time. In total, 5 experiments were conducted in which soak time remained constant: experiment 1 was performed at 1200℃, exp. …

Trends In Streamflow And Precipitation For Selected Sites In The Elkhorn River Basin And In Streamflow In The Salt Creek And Platte River Basins, Nebraska, 1961–2011, Benjamin J. Dietsch, Kellan R. Strauch

United States Geological Survey: Publications

To better understand the streamflow trends at the streamgages in the Elkhorn River Basin in Nebraska, the U.S. Geological Survey (USGS) in cooperation with the Lower Elkhorn Natural Resources District further investigated streamflow trends at the eight streamgages on the Elkhorn River, Salt Creek, and the Lower Platte River that indicated a positive trend in streamflow characteristics and analyzed precipitation trends in the four basins upstream from the Elkhorn River Basin streamgages. An analysis of four streamgages in the Elkhorn River Basin, one streamgage in Salt Creek Basin, and three streamgages in the Lower Platte River Basin that had previously …

Modeling Escherichia Coli In The Missouri River Near Omaha, Nebraska, 2012–16, Brenda K. Densmore, Brent M. Hall, Matthew T. Moser

United States Geological Survey: Publications

The city of Omaha, Nebraska, has a combined sewer system in some areas of the city. In Omaha, Nebr., a moderate amount of rainfall will lead to the combination of stormwater and untreated sewage or wastewater being discharged directly into the Missouri River and Papillion Creek and is called a combined sewer overflow (CSO) event. In 2009, the city of Omaha began the implementation of their Long Term Control Plan (LTCP) to mitigate the effects of CSOs on the Missouri River and Papillion Creek. As part of the LTCP, the city partnered with the U.S. Geological Survey (USGS) in 2012 …

Annotated Bibliography Of Scientific Research On Greater Sage-Grouse Published From 2015 To 2019, Sarah K. Carter, Robert S. Arkle, Heidi L. Bencin, Benjamin R. Harms, Daniel J. Manier, Aaron N. Johnston, Susan L. Phillips, Steven E. Hanser, Zachary H. Bowen

United States Geological Survey: Publications

The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and …

Groundwater Availability Of The Northern High Plains Aquifer In Colorado, Kansas, Nebraska, South Dakota, And Wyoming, Steven M. Peterson, Jonathan P. Traylor, Moussa Guira

United States Geological Survey: Publications

The Northern High Plains aquifer underlies about 93,000 square miles of Colorado, Kansas, Nebraska, South Dakota, and Wyoming and is the largest subregion of the nationally important High Plains aquifer. Irrigation, primarily using groundwater, has supported agricultural production since before 1940, resulting in nearly $50 billion in sales in 2012. In 2010, the High Plains aquifer had the largest groundwater withdrawals of any major aquifer system in the United States.Nearly one-half of those withdrawals were from the Northern High Plains aquifer, which has little hydrologic interaction with parts of the aquifer farther south. Land-surface elevation ranges from more than 7,400 …

Biotic And Abiotic Factors Influencing Arsenic Biogeochemistry And Toxicity In Fluvial Ecosystems: A Review, Laura Barral-Fraga, María Teresa Barral, Keeley L. Macneill, Diego Martiñá-Prieto, Soizic Morin, María Carolina Rodríguez-Castro, Baigal-Amar Tuulaikhuu, Helena Guasch

School of Natural Resources: Faculty Publications

This review is focused on the biogeochemistry of arsenic in freshwaters and, especially, on the key role that benthic microalgae and prokaryotic communities from biofilms play together in through speciation, distribution, and cycling. These microorganisms incorporate the dominant iAs (inorganic arsenic) form and may transform it to other arsenic forms through metabolic or detoxifying processes. These transformations have a big impact on the environmental behavior of arsenic because different chemical forms exhibit differences in mobility and toxicity. Moreover, exposure to toxicants may alter the physiology and structure of biofilms, leading to changes in ecosystem function and trophic relations. In this …

Lunar Magnetic Field Models From Lunar Prospector And Selene/Kaguya Along‐Track Magnetic Field Gradients, Dhananjay Ravat, M. E. Purucker, N. Olsen

Earth and Environmental Sciences Faculty Publications

We use L1‐norm model regularization of |Br | component at the surface on magnetic monopoles bases and along‐track magnetic field differences alone (without vector observations) to derive high quality global magnetic field models at the surface of the Moon. The practical advantages to this strategy are the following: monopoles are more stable at closer spacing in comparison to dipoles, improving spatial resolution; L1‐norm model regularization leads to sparse models which may be appropriate for the Moon which has regions of localized magnetic field features; and along‐track differences reduce the need for ad‐hoc external field noise reduction strategies. We examine also …

Crustal Composition And Moho Variations Of The Central And Eastern United States: Improving Resolution And Geologic Interpretation Of Earthscope Usarray Seismic Images Using Gravity, H. L. Zhang, Dhananjay Ravat, A. R. Lowry

Earth and Environmental Sciences Faculty Publications

EarthScope's USArray Transportable Array has shortcomings for the purpose of interpreting geologic features of wavelengths less than the Transportable Array station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce nonuniqueness in the interpretation of gravity anomalies. We model gravity anomalies from previously derived density variations of sedimentary basins, crustal V p /V s variation, Moho variation, and upper mantle density variation derived from body wave imaging informed by surface wave tomography to estimate V p/V s. Although average densities and density contrasts for these seismic …

Geochemical Constraints On Mantle Sources And Basalt Petrogenesis In The Strait Of Sicily Rift Zone (Italy): Insights Into The Importance Of Short Lengthscale Mantle Heterogeneity., John C. White, David A. Neave, Silvio G. Rotolo, Don F. Parker

EKU Faculty and Staff Scholarship

Igneous activity from the late Miocene to historic time (most recently 1891 ce) in the Strait of Sicily has created two islands (Pantelleria and Linosa) and several seamounts. These volcanoes are dominated by transitional (ol+hy-normative) to alkaline (ne-normative) basaltic lavas and scoriae; peralkaline felsic rocks (trachyte-rhyolite) crop out only on Pantelleria. Although most likely erupted through continental crust, basalts demonstrate no evidence of crustal contamination and are geochemically similar to oceanic island basalts (OIB). Despite their isotopic similarities, there are considerable compositional differences with respect to major and trace element geochemistry both between and within the two islands that are …

Abiotic Formation Of Dissolved Organic Sulfur In Anoxic Sediments Of Santa Barbara Basin, Hussain A. Abdulla, David J. Burdige, Tomoko Komada

OES Faculty Publications

Sulfurization has been found to enhance organic matter preservation and petroleum formation in marine sediments. However, we do not yet have a comprehensive understanding of sulfurization mechanisms. In this study, we investigated several possible mechanisms of dissolved organic sulfur (DOS) formation in the top 4.5 m of anoxic sediments of Santa Barbara Basin (SBB), California Borderland. Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS), we identified chemical formulas of potential dissolved organic matter (DOM) precursors to these DOS compounds. We also examined how the formulas of abiotically formed DOS changed as a function of depth across a major redox …

Water Sourcing Strategies Of Highly Resilient Vegetation In Desert Soils: Stable Isotope Analysis Of A Northern Chihuahuan Desert Ecosystem, Hayden Eleanor Thompson

Open Access Theses & Dissertations

Plant water use strategies and water transport dynamics are important for understanding ecosystem productivity and soil-vegetation-atmosphere interactions within an environment (Li et al., 2007). Recent research using stable isotope analysis in wet and humid climates has found that vegetation uses tightly particle-bound water stored in the soil that does not participate in translatory flow (Brooks et al., 2010; Goldsmith et al., 2011; McDonnell 2014). In arid and semi-arid deserts of the United States, highly resilient vegetation, such as the Honey Mesquite (Prosopis glandulosa) and the Creosote shrub (Larrea tridentata), exhibit some degree of activity year-round despite limited water availability during …

Isotopic And Geochemical Tracers Of Groundwater Flow In The Shivwits Plateau, Grand Canyon National Park, Jonathan W. Wilson

Theses and Dissertations--Earth and Environmental Sciences

As the impacts of global climate change on water resources continue to become more apparent, proper understanding and management of groundwater resources will be needed as supplies become more strained. Traditional methods of characterizing groundwater systems are time-intensive, costly, and can be difficult to complete in remote areas. Using ambient geochemical tracers from discrete sampling could aid in characterizing spring systems through determining flow paths, recharge areas, and carbon cycling. However, using discrete seasonal samples to understand the hydrogeology of complex, mixed-lithology aquifers has not been extensively examined. Here we explore using δ¹³C of dissolved organic carbon (DOC), …