Browsing Geology by Title
Now showing items 119-138 of 172
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Quantification of Permeability-Porosity Relationships in Seafloor Vent Deposits: Dependence on Pore Evolution Processes
(2011)Hydrothermal mineral deposits formed along seafloor spreading centers help regulate the transfer of heat and mass from Earth's interior to the oceans. Aqueous fluids circulate within the seafloor and are emitted through ... -
Quantitative modeling of mantle heterogeneity and structure
(2010)Mantle-derived rocks, particularly mid-ocean ridge basalts (MORB) and intraplate ocean island basalts (OIB), provide insights into the compositional heterogeneity and first-order structural make-up of the modern mantle; ... -
Rb-Sr Radiometric Dating of Rocky Planetary Bodies via LA-ICPMS
(2021)Constraining ages of surface features on rocky objects in the Solar System provides fundamental insights about the flux of impactors through time (including the putative Late Heavy Bombardment), rates of tectonic and ... -
RE-OS AND OXYGEN SYSTEMATICS OF VARIABLY ALTERED ULTRAMAFIC ROCKS, NORTH CAROLINA
(2020)This study focuses on the origin and modification of six ultramafic bodies located in the Blue Ridge Province of North Carolina. The bodies consist mainly of harzburgites and dunites with associated chromites. Some of the ... -
Reaction rates and textural development of hydrolysis reactions in the system MgO-SiO2-H2O
(2011)Experiments in the simplified systems MgO-SiO<sub>2</sub>-H<sub>2</sub>O (MSH) and MgO-SiO<sub>2</sub>-H<sub>2</sub>O-CO<sub>2</sub> (MSHC) have been conducted by using hydrothermal diamond anvil cells to investigate ... -
The Redox History of the Earth's Mantle: Evidence from Ultramafic Lavas
(2019)In order to determine the evolution of the redox state of the mantle, the oxygen fugacities of sixteen mantle-derived komatiitic and picritic systems, ranging in age from 3.55 Ga to present day, were determined using the ... -
Rhenium-Osmium Age Determinations of Glaciogenic Shales from the Mesoproterozoic Vazante Formation, Brazil
(2006-12-12)The Vazante Group is a sedimentary package of carbonate interbedded with diamictite and organic-rich shale, potentially representing a Pleistocene-style glacial cycle of Proterozoic age in Brazil. Lacking volcanic ashes, ... -
ROCK FABRIC ANALYSIS OF THE SIERRA CREST SHEAR ZONE SYSTEM, CALIFORNIA: IMPLICATIONS FOR CRUSTAL-SCALE TRANSPRESSIONAL SHEAR ZONES
(2004-12-08)Crustal-scale tabular shear zones are common features of transpressional orogens and arcs. Though foliation development in shear zones is well understood, the development of another rock fabric element, lineation, is not. ... -
ROCK FLUID INTERACTION AND ITS EFFECT ON BRITTLE ROCK DEFORMATION
(2019)Accurate assessments of Earth’s dynamic processes, which produce earthquakes and volcanoes, require better understanding of rock deformation. All rocks, to some extent, contain pores. In the Earth’s crust, the pore space ... -
The role of mechanical mixing in the formation of reaction zones in subduction-related melange
(2013)Traverses across metamorphic reaction zones at contacts between mafic rocks and ultramafic mélange matrix were analyzed in two mélange zones (Catalina Schist, Santa Catalina Island, CA, and Attic-Cycladic ... -
The Role of Water and Strain Rate in the Deformation of Limestone
(2017)Fluids are pervasive throughout the Earth’s crust. Fluid-rock interaction can significantly alter the mechanical and petrophysical properties of host rocks. This study focuses on the role of fluids in weakening porous ... -
Scales of Bank Roughness and Their Relationship to Bank Erosion Processes
(2009)Stream bank erosion rates and the stabilization of channel width are poorly understood processes. There have been two distinct approaches to the study and prediction of bank erosion rates in natural streams. In order to ... -
THE SEDIMENT AND CRUSTAL STRUCTURE OF THE SOUTHEASTERN UNITED STATES
(2019)The Southeastern United States (SEUS) preserves a detailed geologic record of the continental collision and rifting that has shaped it over billions of years. Currently the SEUS lies on a passive margin far away from ongoing ... -
Seismic Observations of Fluvial Energy Dissipation
(2018)Observing microseismic waves excited by turbulent flow is an emerging way to document river dynamics during extreme flood events. This thesis records fluvial-seismic observations in two contrasting systems at different ... -
The Seismic Signatures of Recently Formed Impact Craters on Mars
(Journal of Geophysical Research Planets, 2019-09)We investigated the seismic signatures of recent impact crater clusters on Mars that would be recorded by the InSight Seismic Experiment for Interior Structure (SEIS) seismometers. We used a database of 77 measured and ... -
A Semianalytical, Three Dimensional Model of Microstructure in Multiparticle, Multiphase Flow
(2011)This dissertation presents a three dimensional microgeodynamic model of grain-melt geometry in partially molten rocks. The isotropic unit cell of the partially molten rock is characterized by a face-centered-cubic symmetry, ... -
Siderophile elements and molybdenum, tungsten, and osmium isotopes as tracers of planetary genetics and differentiation: Implications for the IAB iron meteorite complex
(2016)Isotopic and trace element abundance data for iron meteorites and chondrites are presented in order to investigate the nature of genetic relations between and among meteorite groups. Nebular and planetary diversity and ... -
Size and shape characteristics of airborne amphibole asbestos and amphibole cleavage fragments
(2015)Data on size and shape characteristics of airborne amphibole asbestos and amphibole cleavage fragments obtained from air-monitoring filters at three mine sites and two industrial sites: (1) Homestake Gold Mine, Lead, South ... -
Size and shape characteristics of amphibole cleavage fragments from milled riebeckite
(2015)Data on size and shape characteristics of riebeckite cleavage fragments. The sample was obtained from the Long Valley Creek Quarry, California. Data were collected in ca. 1978-1979. Data values were obtained with Scanning ... -
Size and shape characteristics of Indian tremolite asbestos
(2016)Size distribution measurements of Indian tremolite asbestos by scanning electron microscopy. This material was characterized by the University of Maryland in collaboration with the US Bureau of Mines as part of studies on ...