Effects Of Terrestrial Weathering On Rare Earth Element Concentrations And Sulfur Isotopic Signatures Of Carbonaceous And Ordinary Chondrites, 2020 University of Arkansas, Fayetteville
Effects Of Terrestrial Weathering On Rare Earth Element Concentrations And Sulfur Isotopic Signatures Of Carbonaceous And Ordinary Chondrites, Ruby Virginia Patterson
Theses and Dissertations
Understanding the effects of weathering of chondrites is essential to gaining accurate and useful information about the formation of our solar system, as well as a more detailed account of the mobilization of chondritic compounds when they encounter terrestrial conditions. Elemental concentrations and stable isotope analyses of chondrites, considered to be the most primordial material in the solar system, are two tools which help unlock the weathering patterns of these specimens when they enter the earth system. However, it is not currently known exactly how time spent in the field alters rare earth element (REE) concentration or δ34S signatures within ...
Early Meteoritic Records Of Asteroidal Melt And Impact Environments, 2020 The University of Western Ontario
Early Meteoritic Records Of Asteroidal Melt And Impact Environments, Brendt Hyde
Electronic Thesis and Dissertation Repository
The characterization of meteorites formed in early melt and impact environments helps deepen our understanding of the processes involved in the formation and modification of terrestrial bodies in the solar system. The main objective of this thesis is to interpret and describe a range of igneous and metamorphic environments on asteroidal bodies, through the chemical, microstructural and isotopic analysis of meteorites, and to place these in the context of evolving rocky bodies in the early protoplanetary disk. Study of the meteorite Northwest Africa (NWA) 869 has led to the novel discovery of a eucrite impactor clast in chondritic regolith material ...
Measured Optical Absorption Cross Sections Of Tio, 2020 Old Dominion University
Measured Optical Absorption Cross Sections Of Tio, Peter Bernath
Chemistry & Biochemistry Faculty Publications
A laboratory emission spectrum of TiO in the visible and near-infrared regions (476–1176 nm) has been calibrated and corrected. High-resolution experimental absorption cross sections for TiO with natural isotopic abundance are provided at a temperature of about 2300 K. These cross sections have been compared with those derived from the ExoMol line list. The experimental cross sections can be used directly as a template for cross correlation TiO detection in hot Jupiter exoplanets.
The Effect Of The 21 August 2017 Total Solar Eclipse On The Phase Of Vlf/Lf Signals, 2019 Schmidt Institute of Physics of the Earth, Moscow
The Effect Of The 21 August 2017 Total Solar Eclipse On The Phase Of Vlf/Lf Signals, A. Rozhnoi, M. Solovieva, S. Shalimov, Dimitar Ouzounov, P. Gallagher, G. Verth, J. Mccauley, S. Shelyag, V. Fedun
Mathematics, Physics, and Computer Science Faculty Articles and Research
An experimental study of the phase and amplitude observations of sub‐ionospheric very low and low frequency (VLF/LF) signals is performed to analyze the response of the lower ionosphere during the 21 August 2017 total solar eclipse in the United States of America. Three different sub‐ionospheric wave paths are investigated. The length of the paths varies from 2,200 to 6,400 km, and the signal frequencies are 21.4, 25.2, and 40.75 kHz. The two paths cross the region of the total eclipse, and the third path is in the region of 40–60% of ...
Impact Cratering Processes On The Earth And Moon: Meteorites, Complex Craters, And The Origin Of The Moon, 2019 The University of Western Ontario
Impact Cratering Processes On The Earth And Moon: Meteorites, Complex Craters, And The Origin Of The Moon, Patrick Hill
Electronic Thesis and Dissertation Repository
This thesis seeks to understand the mechanism of hypervelocity impacts, lunar origin and geology, and stable isotope techniques and its application to lunar material. Three lunar regolith breccias, Dhofar 1673, Dhofar 1983, and Dhofar 1984, were examined. The petrography, mineralogy, isotope chemistry, and bulk chemistry of these meteorites were quantified to investigate their origin. The chemistry of the impact melt rock and bulk chemical analysis suggests sourcing from either the Feldspathic or Outer Feldspathic Highland Terranes. Given the similarities in the meteorites, and the proximal location of each find (within 500 m), this thesis proposes strong evidence for their pairing ...
Paired Bulk Organic And Individual Amino Acid Δ15n Analyses Of Bivalve Shell Periostracum: A Paleoceanographic Proxy For Water Source Variability And Nitrogen Cycling Processes, 2019 Iowa State University
Paired Bulk Organic And Individual Amino Acid Δ15n Analyses Of Bivalve Shell Periostracum: A Paleoceanographic Proxy For Water Source Variability And Nitrogen Cycling Processes, Nina M. Whitney, Beverly J. Johnson, Philip T. Dotsie, Katherine Luzier, Alan D. Wanamaker Jr.
Geological and Atmospheric Sciences Publications
Developing high resolution, well-dated marine proxies of environmental, climatic, and oceanographic conditions is critical in order to advance our understanding of the ocean’s role in the global climate system. While some work has investigated bulk and compound specific stable nitrogen isotopes (δ15N) in bivalve shells as proxies for environmental variability, the small concentrations of nitrogen found in the organic matrix of the shell calcium carbonate (CaCO3) makes developing high resolution records challenging. This study investigates the potential of using the bulk and amino acid δ15N of bivalve periostracum, the protein layer on the outside of the shell, as a ...
Multivariate Spectral Analysis Of Crism Data To Characterize The Composition Of Mawrth Vallis, 2018 Wesleyan University
Multivariate Spectral Analysis Of Crism Data To Characterize The Composition Of Mawrth Vallis, Melissa Luna
No abstract provided.
Aluminum-26: A Canonized Cosmochemical Conundrum, 2018 The Graduate Center, City University of New York
Aluminum-26: A Canonized Cosmochemical Conundrum, John Anton
Dissertations, Theses, and Capstone Projects
This study focuses on the challenges associated with the historical development of the interpretative role of 26Al as both a thermodynamic contributor to planetesimal formation processes and an acutely precise chronometer of protoplanetary disk events. Conventional thought asserts that 26Mg concentrations can occur as isotopic excesses in meteorites and represent the daughter product of 26Al, a radioactive form of aluminum (t½ = ~0.73 ka). The greatest 26Mg concentrations generally occur in calcium aluminum inclusions (CAIs), meteoric constituents considered among the oldest known materials in the Solar System whose formation appear to predate the less refractory ...
Phase Transitions In Mgsio3 Post-Perovskite In Super-Earth Mantles, 2017 Iowa State University and Ames Laboratory
Phase Transitions In Mgsio3 Post-Perovskite In Super-Earth Mantles, Koichiro Umemoto, Renata M. Wentzcovitch, Shunqing Wu, Min Ji, Cai-Zhuang Wang, Kai-Ming Ho
Ames Laboratory Accepted Manuscripts
The highest pressure form of the major Earth-forming mantle silicate is MgSiO3 post-perovskite (PPv). Understanding the fate of PPv at TPa pressures is the first step for understanding the mineralogy of super-Earths-type exoplanets, arguably the most interesting for their similarities with Earth. Modeling their internal structure requires knowledge of stable mineral phases, their properties under compression, and major element abundances. Several studies of PPv under extreme pressures support the notion that a sequence of pressure induced dissociation transitions produce the elementary oxides SiO2 and MgO as the ultimate aggregation form at ∼3 TPa. However, none of these studies have addressed ...
The Formation Of Fine-Grained Chondrule Rims In Unequilibrated Ordinary Chondrites, 2017 The Graduate Center, City University of New York
The Formation Of Fine-Grained Chondrule Rims In Unequilibrated Ordinary Chondrites, John Bigolski
Dissertations, Theses, and Capstone Projects
Fine-grained rims are ubiquitous, non-igneous, features that completely or partially envelope the majority of chondrules within the least equilibrated of the unequilibrated ordinary chondrites (UOCs). A detailed examination of such rims in 4 UOC samples less than petrologic type 3.2 was conducted in order to 1) characterize the relative distribution of rims within chondrite samples, 2) inspect differences between fine-grained rims and adjacent matrix material, 3) petrologically analyze the rims and their relationships with chondrule cores, 4) characterize an ungrouped UOC, Northwest Africa 5717, 5) conduct a microanalytical investigation of rim / matrix boundaries to discern relative chronologies of fine-grained ...
Enstatite Achondrites As Indicators Of Processes And Environments In The Early Solar System, 2017 The University of Western Ontario
Enstatite Achondrites As Indicators Of Processes And Environments In The Early Solar System, Diego David Uribe
Electronic Thesis and Dissertation Repository
This thesis investigates the processes and environments of formation of the anomalous enstatite achondrites NWA 4301, Zakłodzie, and NWA 8173 to determine how they relate to other enstatite meteorites (chondrites, impact melt rocks, aubrites, and so-called “primitive enstatite achondrites”). Observations of Zakłodzie and NWA 4301 showed both meteorites may share a common parent body, but experienced different metamorphic conditions. Different zonation patterns in plagioclase, silica polymorphs and associations, and sulfide assemblages indicate Zakłodzie experienced higher metamorphic temperatures and cooled faster than NWA 4301, therefore NWA 4301 was buried deeper in the parent body relative to Zakłodzie. In NWA 8173, mineral ...
Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, 2017 University of New Mexico
Magmatic Hydrothermal Alteration And Secondary Post-Shock Features In Martian Olivine-Phyric Basalt Northwest Africa 10416; Petrology And Geochemistry Of Primitive Achondrite Northwest Africa 11042, Zoltan Vaci
Earth and Planetary Sciences ETDs
The Martian olivine-phyric basalt Northwest Africa (NWA) 10416 contains large olivine xenocrysts whose cores have been stained brown by hydrothermal alteration and whose rims are composed of pristine olivine overgrowths. Microanalysis of these olivine cores reveals various degrees of amorphization, some of which have been overprinted by terrestrial weathering, evident as part of a weathering rind along the exposed surface of the meteorite. Studies of a completely unweathered terrestrial analogue basalt from southern Colorado reveal similar features and indicate that both basalts were altered in a supersolidus magma chamber setting. The alteration features in NWA 10416 thus imply the presence ...
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, 2017 University of Kentucky
Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali
Chemistry Faculty Publications
How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence ...
Stable Isotope Chemistry In Titan Haze Aerosol, 2017 University of Northern Iowa
Stable Isotope Chemistry In Titan Haze Aerosol, Allison Wold
Research in the Capitol
Titan, a moon of Saturn, has a thick atmosphere made up of nitrogen and a few percent methane, with a surface pressure of 1.5x that of Earth. Titan’s atmosphere is believed to be that similar to that of early Earth before the rise of O2. One significant source of information on the history and evolution of the atmosphere is the measurement of stable isotopes of elements in the molecules of major gases such as nitrogen, methane, and higher order hydrocarbons. The fractionation associated with the formation of Titan aerosol analogs are explored in the laboratory as a function ...
Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, 2016 University of Kentucky
Photocatalytic Reduction Of Fumarate To Succinate On Zns Mineral Surfaces, Ruixin Zhou, Marcelo I. Guzman
Chemistry Faculty Publications
The reductive tricarboxylic acid (rTCA) cycle is an important central biosynthetic pathway that fixes CO2 into carboxylic acids. Among the five reductive steps in the rTCA cycle, the two-electron reduction of fumarate to succinate proceeds nonenzymatically on the surface of photoexcited sphalerite (ZnS) colloids suspended in water. This model reaction is chosen to systematically study the surface photoprocess occurring on ZnS in the presence of [Na2S] (1–10 mM) hole scavenger at 15 °C. Experiments at variable pH (5–10) indicate that monodissociated fumaric acid is the primary electron acceptor forming the monoprotic form of succinic acid ...
40ar/39ar Ages Of Lunar Impact Glasses: Relationships Among Ar Diffusivity, Chemical Composition, Shape, And Size, 2015 University at Albany, State University of New York
40ar/39ar Ages Of Lunar Impact Glasses: Relationships Among Ar Diffusivity, Chemical Composition, Shape, And Size, John W. Delano Phd, Nicolle Zellner
Atmospheric and Environmental Science Faculty Scholarship
Lunar impact glasses, which are quenched melts produced during cratering events on the Moon, have the potential to providenot only compositional information about both the local and regional geology of the Moon but also information about the impact flux over time. We present in this paper the results of 73 new 40Ar/39Ar analyses of well-characterized, inclusion-free lunar impact glasses and demonstrate that size, shape, chemical composition, fraction of radiogenic 40Ar retained, and cosmic ray exposure (CRE) ages are important for 40Ar/39Ar investigations of these samples. Specifically, analyses of lunar impact glasses from the Apollo 14, 16, and 17 ...
Insights Into Planetesimal Evolution: Petrological Investigations Of Regolithic Howardites And Carbonaceous Chondrite Impact Melts, 2015 University of Tennessee - Knoxville
Insights Into Planetesimal Evolution: Petrological Investigations Of Regolithic Howardites And Carbonaceous Chondrite Impact Melts, Nicole Gabriel Lunning
Asteroidal meteorites are the only available geologic samples from the early part of our solar system’s history. These meteorites contain evidence regarding how the earliest protoplanetary bodies formed and evolved. I use petrological and geochemical techniques to investigate the evolution of these early planetesimals, focusing on two meteorite types: Howardites, which are brecciated samples of a differentiated parent body (thought to be the asteroid 4 Vesta), and CV chondrites, which are primitive chondrites that have not undergone differentiation on their parent body.
Quantitative petrological analysis and characterization of paired regolithic (solar wind-rich) howardites indicate that this large sample of ...
Exploring Martian Magmas: From The Mantle To The Regolith, 2014 University of Tennessee - Knoxville
Exploring Martian Magmas: From The Mantle To The Regolith, Arya Sigrid Waltraud Udry
The planet Mars is geologically more similar to Earth than to other planets of the solar system. For the past 50 years, new rovers, orbital spacecraft, and new martian meteorites have helped us to understand the geological processes that occurred on Mars. In this dissertation, I investigate a wide range of martian igneous compositions, such as shergottite and nakhlite meteorites, Gusev and Gale surface basalts, and the Northwest Africa (NWA) 7034 breccia. I attempt to better understand magmatic processes that occurred in the martian mantle and crust as well as surficial processes using various petrologic and geochemical tools.
As shown ...
Hunting Starstuff: Searching For Calcium-Aluminum-Rich Inclusions In Cometary Dust, 2014 Space Sciences Laboratory
Hunting Starstuff: Searching For Calcium-Aluminum-Rich Inclusions In Cometary Dust, Christian Engelbrecht
STAR Program Research Presentations
NASA’s Stardust mission (1999 - 2006) returned physical samples of the particles ejected by the comet 81P/Wild 2, collected in ultralight and extremely low density aerogel. These samples have been extensively analyzed using X-Ray Fluorescence (XRF), among other techniques, to determine the elemental, chemical and mineralogical composition of Wild 2. Because comets are thought to be formed in the icy outer regions of the solar system, billions of years ago, the Stardust data gives us details of the composition of the ancient solar system and its subsequent evolution. One of the surprises to come out of the data is ...
Survey Of ‘Low-Z’ Particles From The Interplanetary Dust Collection In Search Of Idps, 2014 Washington University in St. Louis - Physics Department
Survey Of ‘Low-Z’ Particles From The Interplanetary Dust Collection In Search Of Idps, Harison Wiesman
Micrometeorites are one of the most common types of extraterrestrial material that fall to the Earth, beside meteorites and interplanetary dust particles (IDPs). All of these materials are known to contain presolar grains that, when studied in the laboratory, provide information about the origin of the solar system and help to constrain models of nucleosynthesis in stars. Recent studies of micrometeorites revealed the presence of a group of particles with very high C contents. These ultra-carbonaceous Antarctic micrometeorites (UCAMMs) are fine-grained, fluffy particles dominated by highly disordered carbonaceous matter. The presence of H and N isotopic anomalies, abundant presolar grains ...