Physical Sciences and Mathematics Commons^™

New Infrared Spectral Data For 27 Asteroids: An Investigation Of Meteorite-Asteroid Relationships By Using The Modified Gaussian Model, Katherine Marie Gietzen

Graduate Theses and Dissertations

Asteroids provide unique insights into the origin and early history of the solar system. Since asteroids are considered to be fairly pristine, studying them provides opportunities to learn more about the primordial solar system, its materials, processes and history. Since the discovery in 1801 of the first asteroid, Ceres, during the era when everyone was searching for the "missing planet", astronomers have been trying to understand what they are, where they came from, why they exist and what they can tell us about how our solar system formed and evolved.

Within the asteroid population are a number of sub-populations, the …

Presence Of A Long-Term Lithospheric Thermal Anomaly: Evidence From Apatite Fission-Track Analysis In Northern New England, Mary K. Roden-Tice, David P. West Jr., Jaime K. Potter, Sarah M. Raymond, Jenny L. Winch

Mary K. Roden-Tice

Apatite fission-track (AFT) ages from 56 samples of Paleozoic and Mesozoic crystalline rocks in New Hampshire, northeastern Vermont, and western Maine range from 70 to 140 Ma and reflect widespread Early to Late Cretaceous cooling. The regional AFT age distributions determined in this study suggest that reactivation of preexisting orogen-parallel faults and the presence of a long-lived thermal anomaly in the lithospheric mantle controlled the late unroofing history of this part of the northern Appalachians. A northeast-trending zone of young, dominantly Late Cretaceous AFT ages (70-118 Ma) extends from southwestern New Hampshire through the central White Mountain region and continues …

Geogram 2009, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Geometry Of The Trachyte Mesa Intrusion, Henry Mountains, Utah: Implications For The Emplacement Of Small Melt Volumes Into The Upper Crust, Paul H. Wetmore, Charles B. Connor, Sarah E. Kruse, Sean Callihan, Geoffrey Pignotta, Ciprian Stremtan, Andrea Burke

Geology Faculty Publications

The Trachyte Mesa intrusion is one of several small satellite bodies to the larger intrusions of the Henry Mountains, Utah. Most previous studies have worked under the assumptions that Trachyte Mesa is blister shaped and intruded into flat and gently NW dipping strata. In this study we combine structural and geophysical data sets to constrain the structural geology of the host lithologies and the unmodified geometry of the intrusion. Trachyte Mesa intrudes a series of northeast trending upright and open folds formed within the Jurassic Entrada Formation. Truncation of these folds at the contact with the overlying Curtis/Summerville formations indicates …

Researching Nitrite Oxidation At High Temperatures, Dolores A. Huang, Jeremy A. Dodsworth, Brian P. Hedlund

Undergraduate Research Opportunities Program (UROP)

15N-nitrate (NO3 -) pool dilution experiments show that ammonia (NH3) is oxidized to nitrate in geothermal springs up to at least 85C; however, nitrite (NO2 -)- oxidizing microorganisms are only known to grow up to 66°C. We hypothesize that thermophilic microorganisms oxidize nitrite to nitrate at high temperatures. Alternatively, it is possible that nitrite is oxidized abiotically. We propose to test these hypotheses by setting up microbial enrichments designed to grow thermophilic nitrite oxidizing bacteria by varying incubation temperature (50, 65, 80°C), oxygen concentration (20% and 5%), and cultivation media. A negative control consisting of filtered spring water (0.1 μm) …

Solar Variability And Climate Processes: The Influence Of Fluctuating Solar Spectral Irradiance On Differential Surface Heating As A Function Of Soil Geochemistry And Radiation Absorption Characteristics, Susan Wahl

Theses and Dissertations

The influence of solar variability on climate has received increasing attention. Much of the research has dealt with fluctuating ultraviolet radiation and its effects in the stratosphere; decadal signatures in cloud cover and their relationship to cosmic rays; and correlations of surface air temperature with various proxies (e.g., sunspot numbers; 10Be from ice cores and marine sediments). Much of the research has focused on changing solar radiation within the upper atmosphere and the propagating effects into the troposphere. However, there is a missing component involving differential surface heating as a function of soil composition and corresponding spectral radiation absorption properties …

Paragneiss Zircon Geochronology And Trace Element Geochemistry, North Qaidam Hp/Uhp Terrane, Western China, Chris G. Mattinson, Joseph L. Wooden, Jian-Xin Zhang, D. K. Bird

All Faculty Scholarship for the College of the Sciences

In the southeastern part of the North Qaidam terrane, near Dulan, paragneiss hosts minor peridotite and UHP eclogite. Zircon geochronology and trace element geochemistry of three paragneiss samples (located within a ∼3 km transect) indicates that eclogite-facies metamorphism resulted in variable degrees of zircon growth and recrystallization in the three samples. Inherited zircon core age groups at 1.8 and 2.5 Ga suggest that the protoliths of these rocks may have received sediments from the Yangtze or North China cratons. Mineral inclusions, depletion in HREE, and absence of negative Eu anomalies indicate that zircon U-Pb ages of 431 ± 5 Ma …

Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma

Dartmouth Scholarship

Osmium is one of the rarer elements in seawater, with typical concentration of approximately 10 x 10(-15) g g(-1) (5.3 x 10(-14) mol kg(-1)). The osmium isotope composition ((187)Os/(188)Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (approximately 1.3) and mantle/cosmic dust (approximately 0.13). Here, we show that the (187)Os/(188)Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximately 0.2) that are processed to extract platinum and other metals to be used primarily …

Late Quaternary Distribution And Biogeography Of The Southern Lake Eyre Basin (Sleb) Megafauna, South Australia, Steve Webb

Steve Webb

Understanding the population demography, species distribution and biogeography of Australia’s megafauna is essential for understanding their extinction. This process is only just beginning, and this article discusses these aspects while concentrating on a particular region; the southern Lake Eyre Basin (SLEB). It is also the first detailed description of the distribution of megafauna across that region of central Australia. The data are based on an extensive longitudinal study of 41 palaeontological sites spread across 250 000km2. Megafauna adaptation and response to extensive environmental change during the late Quaternary is reflected in the composition and distribution of 21 megafauna species found …

Coesite In Eclogite From The North Qaidam Mountains And Its Implications, Jian-Xin Zhang, Fan-Cong Meng, Jin-Ping Li, Chris G. Mattinson

All Faculty Scholarship for the College of the Sciences

Coesite provides direct evidence for ultrahigh pressure metamorphism. Although coesite has been found as inclusions in zircon in paragneiss of the north Qaidam Mountains, it has never been identified in eclogite. In this contribution, based on petrographic observations and in situ Raman microprobe spectroscopy, coesite was identified as inclusions in garnet of eclogite from the Aercituoshan, Dulan UHP metamorphic unit, north Qaidam Mountains. Coesite is partly replaced by quartz, showing a palisade texture. This is the first report on coesite in eclogite from the north Qaidam Mountains, and is also supported by garnet-omphacite-phengite geothermobarometry (2.7–3.25 GPa, 670–730°C). Coesite and its …

Exhumation Of The Inyo Mountains, California: Implications For The Timing Of Extension Along The Western Boundary Of The Basin And Range Province And Distribution Of Dextral Fault Slip Rates Across The Eastern California Shear Zone, Jeffrey Lee, Daniel F. Stockli, Lewis A. Owen, Robert C. Finkel, Roman Kislitsyn

All Faculty Scholarship for the College of the Sciences

New geologic mapping, tectonic geomorphologic, ¹⁰Be terrestrial cosmogenic nuclide, and (U-Th)/He zircon and apatite thermochronometric data provide the first numerical constraints on late Cretaceous to late Quaternary exhumation of the Inyo Mountains and vertical slip and horizontal extension rates across the eastern Inyo fault zone, California. The east-dipping eastern Inyo fault zone bounds the eastern flank of the Inyo Mountains, a prominent geomorphic feature within the western Basin and Range Province and eastern California shear zone. (U-Th)/He zircon and apatite thermochronometry yield age patterns across the range that are interpreted as indicating: (1) two episodes of moderate to rapid …

Stable Isotopes And Climate Change, Ray Bradley, Rob Snyder

IPY STEM Polar Connections

The following description of the role of the study of stable isotopes in water and carbon dioxide molecules when constructing a record of Earth’s pattern of climate change is an excerpt from:

Climate Change and Society by Raymond S. Bradley & Norman E. Law (2001) Nelson Thornes, Cheltenham, UK (ISBN: 0 7487 5823 2)

Mercury Uptake By Aquatic Macrophytes In Urban And Rural Watersheds, Albany County, Ny, Bernd G. Neumann

Geology Theses and Dissertations

Plants growing in metalliferous soils may restrict metal uptake and transport depending on metal concentration, sediment characteristics, and plant species. As native plants are replaced by invasives, different patterns of metal cycling can occur, making continued study of this process important. Sediments and tissues of four aquatic plant species/genera: Phragmites australis (common reed); Iris versicolor (blueflag iris); Typha latifolia (broadleaf cattail); and genera Cyperus sp. (sedge) from three urban and two rural sites in Albany County, NY were analyzed for total mercury (Hg_­T) by cold vapor atomic absorption spectroscopy. Sediments were also measured for organic carbon (OC) by …

Estimating Variation In Stiffness And Volume Change Of Clays From Geochemical And Index Properties, Cynthia Roxanna Zuniga

Open Access Theses & Dissertations

Clayey soils from six different locations in Texas were analyzed and evaluated with respect to their expansion and shrinkage and change in stiffness associated with moisture content variation. These soils consist of five high plasticity-index (PI) clays (PI greater than 25) and one low-PI clay (PI = 17). The behavior of the clays changes dramatically with moisture content fluctuation, thus causing stiffness and volume changes throughout the year. Total or differential volume movements caused by swell or shrinkage strains of expansive soils and reduction in modulus can exert enough pressure to damage the pavements and cause maintenance problems.

The intent …

Biogenic Tracers Through The Holocene On The Alaskan Shelf, Carie A. Curry

OES Theses and Dissertations

Dramatic environmental changes in the Arctic Ocean have been observed for the last two decades including changing the amount of sea ice thickness and extent, and increased river discharge. In order to put these and other current day observations into historical context and perhaps reveal mechanisms controlling them, a suite of paleo-proxies were used to analyze two high resolution cores collected on the 2005 HOTRAX expedition. The goals of this research were: (1) develop an analytical method for determining biogenic calcite, (2) identify the major sources of biogenic matter into the system over the Holocene, and (3) assemble the history …

Characterization Of Firn Microstructure Using Scanning Electron Microscopy: Implications For Physical Properties Measurements And Climate Reconstructions, Nicole Spaulding

Electronic Theses and Dissertations

Samples from 12 East Antarctic firn and ice cores were analyzed using scanning electron micrcoscopy (SEM) in order to first develop a technique for the accurate characterization of physical properties and then to investigate the relationship between the physical microstructure and chemical properties. Both physical properties, such as grain size and porosity, and chemical properties, such as major ion and trace element concentration, provide information about atmospheric temperature changes, impurity content, accumulation rate and deformation history; therefore the characterization of both types of properties is necessary. Further, knowledge of the relationship between the physical and chemical properties may increase our …

Riparian And Associated Habitat Characteristics Related To Nutrient Concentrations And Biological Responses Of Small Streams In Selected Agricultural Areas, United States, 2003–04, Ronald B. Zelt, Mark D. Munn

Publications of the US Geological Survey

Physical factors, including both in-stream and riparian habitat characteristics that limit biomass or otherwise regulate aquatic biological condition, have been identified by previous studies. However, linking the ecological significance of nutrient enrichment to habitat or landscape factors that could allow for improved management of streams has proved to be a challenge in many regions, including agricultural landscapes, where many ecological stressors are strong and the variability among watersheds typically is large. Riparian and associated habitat characteristics were sampled once during 2003–04 for an intensive ecological and nutrients study of small perennial streams in five contrasting agricultural landscapes across the United …

Suswa Volcano, Kenya Rift: Evidence Of Magma Mixing, Na-F Complexing And Eruptions Triggered By Recharge, Vanessa Veronica Espejel Garcia

Open Access Theses & Dissertations

The Cenozoic East African rift system (EARS) is a sequence of grabens, intraplate transforms, accommodation zones, and abundant magmatism. The Central Kenya Peralkaline Province (CKPP) includes a variety of volcanic rocks -trachyte, pantellerite, comendite, phonolite, trachy-basalt, basaltic trachy-andesite, and basalt- which erupted from volcanoes including: Mount Kenya; Eburru and the Greater Olkaria volcanic complexes; Longonot, Menengai, and Suswa volcanoes; and Ndabibi, Elmenteita, and Tandamara mafic volcanic fields. Only two of the volcanoes, Mount Kenya (on the flank of the central graben) and Suswa (the southernmost of the CKPP volcanoes), have phonolites as part of their assemblage.

The evolution of Suswa …

Geochemical Fingerprinting Of Volcanic Airfall Deposits : A Tool In Stratigraphic Correlation, Soumava Adhya

Legacy Theses & Dissertations (2009 - 2024)

Chemical fingerprints of volcanic airfall deposits obtained from high-precision electron microprobe analysis of glass and phenocrysts phases provide geochemical correlations with temporal precision unattainable by other methods. In this research electron microprobe analysis (EMA) techniques, to fingerprint chemically and correlate fresh and altered volcanic airfall deposits, have been utilized to test the value of this tool for future research on stratigraphic correlation. The following samples were chosen from within a variety of sedimentary rocks widely separated spatially and temporally:

Export Of Terrestrial Dissolved Organic Matter Along A River To Ocean Transect Of The Lower Chesapeake Bay Investigated By Advanced Analytical Techniques, Rachel Leigh Sleighter

Chemistry & Biochemistry Theses & Dissertations

Ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proved essential for the complete separation of the thousands of peaks present in natural organic matter (NOM), a complex assemblage of organic molecules present in water, soils, and sediments. An improved understanding of its composition is crucial to understand how pollutants interact with NOM and how NOM cycles through global carbon cycles.

Optimizing the acquisition and handling of the FTICR mass spectra is the first step to obtaining high quality data. A simple method to internally calibrate the peaks in the complex spectra, using naturally present fatty …

Cave Minerals Of San Salvador Island, Bahamas, Bogdan P. Onac, Jonathan Sumrall, John E. Mylroie, Joe B. Kearns

Environmental Sustainability Books

This volume describes the results of a 2009 fieldwork season focusing on the cave minerals found in karst environments throughout San Salvador Island in the Bahamian archipelago. The caves visited represent a sampling of pit and flank margin caves. Each cave description includes a map.

Zinc And Copper Isotopes As Tracers Of Anthropogenic Contamination In A Sediment Core From An Urban Lake, Anita Thapalia

Open Access Theses & Dissertations

Concentration data alone are often insufficient to resolve metal sources. This study applies stable Zn and Cu isotopes to fingerprint and track the sources of these metals in a sediment core from Lake Ballinger near Seattle, Washington, USA. The base of the Lake Ballinger core pre-dates settlement in the region, while the upper sections record the impact of atmospheric emissions from the nearby Tacoma smelter, as well as Cu and Zn inputs from urban sources. δ⁶⁶Zn and δ⁶⁵Cu varied by 0.42 / and 0.29 /, respectively, over the >300 year core record. Isotopic changes were correlated …

Using Chromium Stable Isotopes To Monitor Chromium Reactive Transport: Oxidation Experiments And Field Studies, Alejandro Villalobos Aragon

Open Access Theses & Dissertations

Chromium (Cr) is a common contaminant found at a number of sites globally. Cr sources can be either anthropogenic or natural. Cr occurs in nature in two valences, with Cr(VI) being carcinogenic, more toxic and mobile than Cr(III). Reduction of Cr(VI) to Cr(III) is a common remediation strategy, but monitoring Cr reduction using only concentration and speciation analyses is a difficult endeavor because concentrations can be affected by dilution and advection in addition to reduction. Cr isotopes are fractionated during reduction processes, so monitoring isotopic changes in Cr may be a faster and more effective way to monitor reduction. This …

Mineralogy And Micromorphology Of An Atacama Desert Soil, Chile: A Model For Hyperarid Pedogenesis, Michael S. Howell

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Atacama Desert is the oldest and driest desert on Earth. Hyperarid soils in this desert are dominated by rare (or exclusive) salt minerals and assemblages. Previous research details salt origins and abundance, however pedogenic processes involved in salt distribution are not adequately explained. Therefore, the main goal of this investigation was to identify and document evidence for hyperarid pedogenesis (via salt mineralogy and soil micromorphology) at a field site, Oficina Ercilla, located ~80 km northeast of Antofagasta, Chile within the Central Depression and hyperarid core of the Atacama Desert. This study presents an interpretational model for hyperarid pedogenesis, which …

In Situ Element Quantification In The Hydrothermal Diamond Anvil Cell Using Synchrotron X-Ray Fluorescence With Applications Toward Subduction Zone Processes, Steven Joseph Maglio

UNLV Theses, Dissertations, Professional Papers, and Capstones

Yttrium is used in geochemical investigations of arc volcanics and metamorphic geothermometers. The ability to use Y as a geochemical tool is predicated on an understanding of the mobility of Y during fluid-saturated conditions attending metamorphic and igneous processes. The goal of this work was to use the hydrothermal diamond anvil cell (HDAC) and synchrotron radiation X-ray fluorescence to quantify, in situ, the concentration of Y in aqueous fluids at 2-5 GPa and 650 - 800 °C; conditions likely at the oceanic lithosphere - mantle wedge interface in subduction zones. Previous studies have used modified diamond anvils which limits their …

Sequence And Chemostratigraphic Study Across The Basal Eureka Quartzite Unconformity In The Great Basin, Nevada: Implications For The Origin Of The Late Ordovician Carbon Isotope Excursion, Apostolos Paul Kosmidis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The positive carbon isotope (δ 13 C) excursion from the late Middle Ordovician Copenhagen Formation that underlies the Eureka Quartzite in central Nevada has been hypothesized to record a global cooling event ∼10 Myr prior to the well-recognized Late Ordovician Hirnantian glaciation (∼443 Ma). However, direct evidence for pre-Hirnantian continental glaciation remains scarce, raising uncertainties in the relationship between the inferred eustatic sea-level fall and the origin of the positive δ 13 C excursion. Additionally, previous stratigraphic studies from southern Nevada and California suggest relative sea-level fall in excess of ∼ 150 meters, which exceeds estimates for younger glacial periods …

Early Neoproterozoic Origin Of The Metazoan Clade Recorded In Carbonate Rock Texture: Reply, Fritz Neuweiler, Elizabeth C. Turner, David J. Burdige

OES Faculty Publications

We (Neuweiler et al., 2009) used scanning electron microscopic, fluorescence spectroscopic, fluorescence microscopic, and thin-section analytical work from modern, Cretaceous, Silurian, and early Neoproterozoic reefal material to make a geological case for an early Neoproterozoic origin of animals. In a modern analogue for ancient petrographic textures, degradative calcification of the extracellular collagenous matrix (ECM) of a modern siliceous sponge can be directly observed (Neuweiler et al., 2007).