Geochemistry Commons^™

Distribution And Impacts Of Petroleum Hydrocarbons In Louisiana Tidal Marsh Sediments Following The Deepwater Horizon Oil Spill, Rachel S. Hatch

Theses and Dissertations--Earth and Environmental Sciences

Following the 2010 Deepwater Horizon (DWH) spill, sediment cores were analyzed from marshes at various levels of oiling to determine how deeply oil penetrated sediment in these marsh environments, and if at these sites it had quantifiably affected benthic ecosystems. Minimum mixing depths were determined from penetration of the lithogenic radionuclide ²³⁴Th, which ranged from 0.25 to 4.5 cm. Sediment accumulation rates were determined using ²¹⁰Pb, with verification from ¹³⁷Cs in selected cores. Lead-210 profiles revealed long-term (decadal) mixing. Bay Jimmy, Louisiana was significantly affected by the DWH oil spill, as indicated by total polycyclic aromatic hydrocarbon …

The Relative Contribution Of Methanotrophs To Microbial Communities And Carbon Cycling In Soil Overlying A Coal-Bed Methane Seep, Christopher T. Mills, Gregpry F. Slater, Robert F. Dias, Stephanie A. Carr, Christopher M. Reddy, Raleigh Schmidt, Kevin W. Mandernack

Chemistry & Biochemistry Faculty Publications

Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH₄ and also a likely source of ancient (i.e. ¹⁴C-dead) carbon to soil microbial communities. Natural abundance ¹³C and ¹⁴C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO₂ and CH₄ were used to assess the incorporation of CBM-derived carbon into methanotrophs and other members of the soil microbial community. Concentrations of type I and type II methanotroph PLFA biomarkers (16:1ω8c and 18:1ω8c, respectively) were elevated in CBM-impacted soils compared with a control site. Comparison …

Rare Earth Element Geochemistry Of The Sierra Blanca Laccoliths, Texas, Amed Gomez

Open Access Theses & Dissertations

No abstract provided.

Abiotic Nitrate And Nitrite Reactivity With Iron Oxide Minerals, Prakash Dhakal

Theses and Dissertations--Plant and Soil Sciences

Under iron (Fe³⁺)-reducing conditions where aqueous Fe²⁺ and unreduced solid Fe³⁺-oxides commonly coexist, soil Fe²⁺ oxidation has been shown to be coupled with nitrate (NO₃^-) reduction. One possible secondary reaction is the involvement of NO₃^- and nitrite (NO₂^-) with Fe-oxide minerals found in many natural environments. Yet, spectroscopic measurements and kinetic data on reactivity of NO₃^- and NO₂^- with Fe-containing oxide minerals such as goethite (a-FeOOH), and magnetite (Fe₃O­₄) are not found in the literature. The reactivity of …

Are 34s-Enriched Authigenic Sulfide Minerals A Proxy For Elevated Methane Flux And Gas Hydrates In The Geologic Record?, Walter S. Borowski, Nancy M. Rodriguez, Charles K. Paull, William Ussler Iii

EKU Faculty and Staff Scholarship

The sulfate–methane transition (SMT) zone is a diagenetic transition within anoxic marine sediments created by the metabolic activity of a consortium of sulfate-reducing bacteria and methane-oxidizing Archaea. As interstitial dissolved sulfate is consumed by microbially mediated sulfate reduction of sedimentary organic matter (SOM) and anaerobic oxidation of methane (AOM) large enrichments of ³⁴S occur in the interstitial sulfate pool. These isotopic enrichments are transmitted to the dissolved sulfide pool (∑HS⁻) and subsequently into sulfide minerals (So, ∼FeS, FeS₂).

We investigate the sulfur isotopic composition of pore-water sulfate and sulfide minerals at three sites underlain …

Cave Ventilation Is Influenced By Variations In The Co2-Dependent Virtual Temperature, Enrique P. Sánchez-Cañete, Penélope Serrano-Ortiz, Francisco Domingo, Andrew S. Kowalski

International Journal of Speleology

Dynamics and drivers of ventilation in caves are of growing interest for different fields of science. Accumulated CO₂ in caves can be exchanged with the atmosphere, modifying the internal CO₂ content, affecting stalagmite growth rates, deteriorating rupestrian paintings or creating new minerals. Current estimates of cave ventilation neglect the role of high CO₂ concentrations in determining air density – approximated via the virtual temperature (T_v) –, affecting buoyancy and therefore the release or storage of CO₂. Here we try to improve knowledge and understanding of cave ventilation through the use of T …

Natural And Anthropogenic Factors Which Influence Aerosol Distribution In Ingleborough Show Cave, Uk, Andrew C. Smith B.S.C, Peter M. Wynn, Philip A. Barker Professor

International Journal of Speleology

Monitoring in Ingleborough Show Cave (N. Yorkshire, UK) reveals the influence of tourism and cave management techniques on different parameters of the cave atmosphere. Exploratory aerosol monitoring identified a 0.015 ± 0.03 mg/m³ (≈70%) reduction in airborne particulates within the first 75 meters of cave passage and two major aerosol sources within this artificially ventilated show cave. Autogenic aerosol production was identified close to active stream ways (increases of

A Model For The Formation Of Layered Soda-Straw Stalactites, Bence Paul, Russell Drysdale, Helen Green, Jon Woodhead, John Hellstrom, Rolan Eberhard

International Journal of Speleology

Climate records based upon instrumental data such as rainfall measurements are usually only available for approximately the last 150 years at most. To fully investigate decadal-scale climate variation, however, these records must be extended by the use of climate proxies. Soda-straw stalactites (straws) are a previously under-utilised potential source of such data. In this contribution we investigate the structure and formation of straws and look at some issues that may affect the reliability of straw-based palaeoclimate records. We use laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analysis to document surface contamination features that have the potential to obscure annual …

Modeling Potential Chemical Environments: Implications For Astrobiology, Brian Craig Szenay

USF Tampa Graduate Theses and Dissertations

Modeling chemical environments is an important step to understanding the diversity of prebiotic systems that may have formed on the early earth or potentially can occur on other worlds. By using the modern Earth as a test case, these models predict scenarios with systems more conducive to the formation of the organic molecules that are important to life. Here we use the equilibrium thermodynamic modeling program HSC Chem to investigate prebiotic environments. This program uses the raw material that the user inputs into the system in order to calculate the change in amounts of chemical species forming as a function …

Geochemical Evidence For Vertical Migration Of Deep Formation Fluids Through The Baton Rouge -Denham Springs Fault System, Lesley C. Prochaska

LSU New Orleans Theses and Dissertations

Accumulations of brackish groundwater exist across south Louisiana within the shallow, south-dipping Pleistocene to Upper Miocene Baton Rouge Aquifer System (BRAS). This research investigates the source of brackish groundwater through geochemical analysis of representative groundwater samples by comparing the following geochemical ratios along with other trace elements. Low Bromide (Br)/Chloride (Cl) and Potassium (K) /Cl ratios, high Sodium (Na) /Cl ratios, trace Magnesium (Mg) concentrations, and low Strontium (Sr) ⁸⁷/Sr⁸⁶ in brackish waters from the BRAS are inconsistent with in situ saline water from marine formation fluids of similar age. The ratios are consistent with in situ saline-water …

Early Permian Seawater From The Delta18o Record Of Fossil Bivalves: Seasonality And A Latitudinal Gradient, James Andrew Beard

Earth & Environmental Sciences - Theses

The transition from a glaciated world to one that was ice-free makes the early Permian a time interval that in many ways mirrors the present, and hence there is great interest in constraining paleoclimate conditions over that transition. A common method for estimating ancient temperatures uses the oxygen isotope composition of marine carbonate, but this approach becomes significantly more complicated prior to the Cretaceous due to uncertainties about diagenesis and the isotopic composition of seawater, which has been hypothesized to be more depleted than during the Cenozoic. I use stable isotope compositions of sequentially microsampled accretionary calcite from fossil bivalves …

Chemical Contaminants As Stratigraphic Markers For The Anthropocene, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Thousands and even millions of years from now, widespread anthropogenic contaminants in sediments would likely persist, incorporated into the geological record. They would inadvertently preserve evidence of our present era (informally designated as the Anthropocene Epoch) characterized by large human populations engaged in intensive industrial and agricultural activities.

Hypothetical geologists in the distant future would likely find unusually high concentrations of a wide variety of contaminants at stratigraphic levels corresponding to our present time, analogous to the iridium anomaly marking the bolide impact event at the close of the Cretaceous Period. These would include both organic and inorganic substances, such …

Glacial Shortcut Of Arctic Sea-Ice Transport, Michael Stärz, Xun Gong, Rüdiger Stein, Dennis A. Darby, Frank Kauker, Gerrit Lohmann

OES Faculty Publications

Due to the lack of data, the extent, thickness and drift patterns of sea ice and icebergs in the glacial Arctic remains poorly constrained. Earlier studies are contradictory proposing either a cessation of the marine cryosphere or an ice drift system operating like present-day. Here we examine the marine Arctic cryosphere during the Last Glacial Maximum (LGM) using a high-resolution, regional ocean-sea ice model. Whereas modern sea ice in the western Arctic Basin can circulate in the Beaufort Gyre for decades, our model studies present an extreme shortcut of glacial ice drift. In more detail, our results show a clockwise …

Assessing Eolian Dust Inputs To Soils In Dry Creek Experimental Watershed, Sw Idaho, Brian Jameson Stark

Boise State University Theses and Dissertations

A geochemical investigation of upland soils in the Dry Creek Experimental Watershed (DCEW) near Boise, Idaho was conducted to assess the potential contributions of eolian dust. Major and trace element compositions of soils within the watershed, loess deposits in the adjacent Western Snake River Plain (WSRP), and underlying granodiorite bedrock were evaluated. Multiple lines of evidence suggest a significant contribution of dust in the soils. Plots of Co/Ti, V/Ti and Cr/Ti indicate that the loess and bedrock occupy distinctly different compositional spaces and that the soils are of intermediate composition, suggesting that the soils are a mixture of the loess …

Geochemical Constraints On Groundwater Recharge In The Royal Slope Area, Grant County, Washington, Zoe Danielle Weis

All Master's Theses

Groundwater, the primary source for potable water in the Columbia Plateau, has experienced significant declines over the past 25 years. Groundwater geochemistry and multivariable statistics were employed to identify and characterize the hydrofacies present, constrain recharge sources, and assess mixing of groundwater in the Royal Slope area of the Columbia Plateau. Geochemical analyses for major ions, stable isotopes, and radiogenic isotopes (14C and tritium) for age dating were performed on groundwater samples collected in 2010 from 24 wells in the study area. The results confirmed that the groundwater evolution in the study area follows the typical Columbia River Basalt Group …

Petrogenesis Of The East Fork Member Rhyolites, Valles Caldera, New Mexico, Usa, Carla Eichler

UNLV Theses, Dissertations, Professional Papers, and Capstones

The most recent volcanism in the Valles caldera is represented by the El Cajete Pyroclastic Beds (ECPB), Battleship Rock Ignimbrite (BRI), and Banco Bonito Flow (BBF) as well as the VC-1 rhyolite, which are collectively known as the East Fork Member (EFM) of the Valles Rhyolite. The EFM was erupted at approximately 55 ka and 40 ka after an approximate 460 ka lull in volcanism. Previous studies suggested a mafic intrusion at depth triggered the eruptions. This thesis represents the first detailed study of the EFM.

Crystal assemblages consist of plagioclase, biotite, clinopyroxene, orthopyroxene, amphibole, sanidine, quartz, and oxides. Electron …

Volcanic Evolution Of The Southern Quinn Canyon Range: Implications For Regional Correlation Of Volcanic Units, Christina Emery

UNLV Theses, Dissertations, Professional Papers, and Capstones

The southern Quinn Canyon Range lies in an area of the Great Basin subjected to large-volume Oligocene-Miocene silicic volcanism and smaller volume basaltic volcanism during the Pliocene. Three major ash-flow tuff units were correlated in the southern Quinn Canyon Range (the Pahranagat Tuff, Clifford Spring Tuff, and the Cow Canyon Tuff) with regional units by utilizing U/Pb and 40 Ar/ 39Ar geochronology, geochemical correlation, and field mapping. Isotopic analysis suggests that basalt in the southern Quinn Canyon Range is part of the Death Valley-Pancake Range Basalt Zone and is similar to Reveille Range Episode 1 and 2 basalts. Further comparison …

Geogram 2012, David J. Keeling, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Investigating The Utility Of Detrital Mineral Microchemistry And Radiogenic Isotope Compositions As Provenance Discriminators, Jack Hietpas

Earth & Environmental Sciences - Dissertations

The provenance of clastic sediments remains one of the key tools for understanding the complex dynamic history of the Earth. Detritus shed from ancient orogens may be the only evidence available for determining the timing, evolution, paleogeography, and existence of tectonic events active over the 4.56 Ga of Earth history. The focus of this dissertation research is to assess the strengths and limitations of existing, as well as novel, tools for determining the provenance of siliciclastic sediments.

The utility of detrital monazite crystallization ages was investigated as a provenance indicator in both modern and ancient sedimentary systems. The results from …

Evaluation Of Possible Source Rocks In Northern Nye County, Nevada: Implications For Hydrocarbon Exploration, Inessa Yurchenko

UNLV Theses, Dissertations, Professional Papers, and Capstones

The presence of oil outside of Railroad Valley, northern Nye County has sparked the interest of exploration companies in Nevada. The geology in this region is very complex and the level of petroleum exploration is low. In order to understand the distribution of oil, a complete petroleum systems analysis is required. Previous studies confirmed that the Mississippian Chainman Shale and Cretaceous to Paleocene Sheep Pass Formation, Member B are source rocks. However, a number of other possible source rocks exist in northern Nye County, but they are not confirmed because of incomplete datasets. The goal of this thesis project is …

The Effects Of Fractures On The Occurrence And Distribution Of Arsenic In The Upper Floridan Aquifer During Aquifer Storage And Recovery, William Charles Hutchings

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Aquifer storage and recovery (ASR) is used world-wide to supplement available water supplies by storing surplus water in aquifers and recovering it during periods of drought and increased demand. The use of ASR as an option for increasing available municipal irrigation and fresh water supplies is threatened as a result of the mobilization of arsenic in some aquifers during ASR. Arsenic is liberated from arsenic-bearing sulfide minerals as a result of the mixing of oxidizing injected water with reducing insitu groundwater. Fracture networks can have significant influence on the migration and distribution of arsenic in the Upper Floridan Aquifer …

A Geochemical Analysis Of Fulgurites: From The Inner Glass To The Outer Crust, Michael L. Joseph

USF Tampa Graduate Theses and Dissertations

Cloud-to-ground lightning strikes produce natural glasses on the surface of the Earth, called fulgurites. These natural glasses are tubular in shape with a central void surrounded by an inner glass, and the inner glass is surrounded by an outer crust or toasted region. Previous studies report different kinds of melts existing in several different types of fulgurites; however, little to no chemical data has been collected that tracks chemical variations from the inner glass to the outer crust of a fulgurite. This study uses microprobe and laser ablation inductively coupled plasma mass spectrometer analytical techniques to collect transects of chemical …

Speciation And Removal Mechanisms Of Rhenium In Anoxic Waters: Roles Of Zero-Valent Sulfur, Mineral Oxide Catalysis, And Pyrite Surfaces, Trent P. Vorlicek

All Private Grants

Global warming is expected to intensify the effects of coastal anoxia. Knowledge of the causes of geohistorical anoxic episodes may prove critical in developing strategies for the mitigation of or adaptation to the consequences of climate change upon the global aquatic environment. The geochemistry of Re provides the means to acquiring this knowledge. Within oxic waters, Re exists as geochemically-inert ReO4-. Under reducing conditions, Re is removed from the aqueous phase and deposited in sediments. Unfortunately, an incomplete understanding of Re geochemistry hampers exploitation of Re as a paleoredox indicator. Authors purport Re sequestration begins in suboxic environments; others produce …

A Study Of Enhanced De-Chlorination And Bio-Remediation: Molasses Injections Into Groundwater, Brent Anderson

Natural Resources Management and Environmental Sciences

No abstract provided.

Estimating Land Surface Temperature Using A Thermal Sharpening Technique, Yitong Jiang, Qihao Weng

Symposium 2012

No abstract provided.

A Mineralogical Textural And Chemical Characterization Of A Hypothesized Kimberlite At White Mountain, Sunlight Basin, Wyoming, Stuart Kenderes

Mahurin Honors College Capstone Experience/Thesis Projects

Geologists have examined the causes and mechanisms responsible for the Heart Mountain detachment for over a century with much debate and discussion. White Mountain is a part of the upper plate, which was emplaced during the detachment event. Within White Mountain, there exist several andesitic dikes and carbonate ultra-cataclasite injectites, which were integral in the emplacement of the Heart Mountain detachment. This research involves the characterization and identification of an enigmatic vertical outcropping of brecciated rock located on White Mountain, Sunlight Basin, Wyoming, which was originally interpreted as a kimberlite. Samples were collected for geochemical and textural comparison, and cut …

The Behavior Of Zircon During Partial Melting In Anatectic Migmatites: Insights To Metamorphism, Deformation And Tectonism In The Central Santa Fe Range, Northern New Mexico, Michelle Renee Stropky

UNLV Theses, Dissertations, Professional Papers, and Capstones

Three lithologic assemblages exposed in the central Santa Fe Range, northern New Mexico include (1) a septum of Proterozoic low temperature (~700oC, 5.5 kbars), semi-pelitic anatectic migmatites surrounded by (2) deformed megacrystic biotite granite that is intruded by (3) discrete plutons of largely undeformed hornblende biotite tonalite. Metamorphic fabrics in the migmatite record three deformation events (D1 - D3); a composite S1/S2 fabric (D1 and D2) that formed contemporaneous with anatexis and is folded about a southwest plunging map-scale (D3) antiform. The megacrystic granite exhibits a pervasive S1 subsolidus foliation that parallels the S1/S2 fabric in the migmatite and is …

Deciphering The Evolution Of Ore Fluids At The Batu Hijau Copper-~Gold Porphyry Deposit, Sumbawa, Indonesia, Jordan Thomas Armstrong

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fluid inclusions contained within quartz veins from the Batu Hijau Cu-Au porphyry deposit in Indonesia were analyzed to track the evolution of fluid temperature, pressure, and composition during the formation of the deposit to better understand the formation of this and other Cu-Au porphyry deposits in order aid future exploration. A combination of petrography, microthermometry, synchrotron x-ray fluorescence, and laser ablation-inductively coupled plasma-mass spectrometry were used to determine the temperature, pressure, and compositional aspects of the deposit.

Four types of fluid inclusions were recognized at Batu Hijau based on the volume percent of the vapor bubble; inclusions were classified as …

Evaluating Recharge And Dynamics Of Flow In The Lower Virgin River Basin, Usa: Interpretation Of Hydrochemical And Stable Isotopic Data, Joseph Asante

UNLV Theses, Dissertations, Professional Papers, and Capstones

Because of the complex geologic setting of the Basin and Range province, groundwater flow systems of the Intermountain basins of the southwestern United States are complex and remain poorly understood. Understanding these flow systems is important for water budgeting on a regional and local scale, and development of robust numerical groundwater models for sustainable water use and protection of water-dependent ecosystems. Although for decades hydrochemistry and isotopes have been used to characterize and trace subsurface water and surface water, effectively interpreting these data are still challenging, which can be attributed to existing subjective grouping of these data and the lack …

Chemical Weathering Of The Mafic Minerals Serpentine And Olivine In Natural Environments, Julie Lynn Baumeister

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chemical weathering is a critical process that plays a key role in controlling the chemistry of natural waters, the cycling of atmospheric carbon dioxide, and the formation of soil. The weathering of silicate minerals is important because the Earth's crust is composed of approximately 92 weight percent silicate minerals. Despite an extensive literature on mineral dissolution and kinetics, relatively few studies have examined weathering of the mafic minerals serpentine and olivine, especially in a natural environment. The first chapter of this thesis provides an introduction to the minerals serpentine and olivine. The second chapter of this thesis examines the important …