Browsing Geology by Title
Now showing items 110-129 of 172
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Petrogenesis of Peraluminous Granites from the Fosdick Mountains, Marie Byrd Land, West Antarctica
(2013)Granites from the Fosdick Mountains, West Antarctica were analyzed for major and trace elements as well as Sr-Nd isotopes ratios in order to investigate the sources and processes associated with granite formation at a ... -
Petrologic and geochronologic constraints on the thermal and structural evolution of paleo-subduction interfaces
(2020)In subduction zones, the interface between the downgoing slab and overriding plate controls a number of important dynamic processes. Both the rheologic behavior and thermal structure of the interface influence fluid release ... -
A PETROLOGIC, GEOCHEMICAL AND OSMIUM ISOTOPIC STUDY OF SELECTED PRECAMBRIAN KOMATIITES
(2004-11-17)The major and trace elements, and Re-Os isotope systematics of the ca. 2.7-Ga komatiites from the Alexo and Dundonald Beach areas in the Abitibi greenstone belt, Canada, and ca. 2.0-Ga komatiites from Jeesiörova, Finnish ... -
Petrologic, Geochemical, and Spectral Characteristics of Oxidized Planetary Differentiation
(2021)Meteorites provide evidence that planetary formation occurred across a wide range of oxidation environments in the early Solar System. While the process of differentiation for many reduced, oxygen-poor assemblages has been ... -
Planetary Seismology using Single-Station and Small-Aperture Arrays: Implications for Mars and Ocean Worlds
(2020)Studying geophysical station deployment on Earth is essential preparation for future geophysical experiments elsewhere in the solar system. Here, I investigated how single-station seismometers and small-aperture seismic ... -
POLYMETALLIC MINERAL DEPOSITS OF THE SYKESVILLE DISTRICT, MARYLAND: ORE-FORMING PROCESSES IN THE APPALACHIAN OROGEN
(2015)Questions remain concerning the genesis and geological setting of the ultramafic rock-associated mineralization of the Sykesville District, Maryland, USA, which is located in the mid-Atlantic Appalachians. Best described ... -
Preservation of Earth-forming events in the tungsten isotopic composition of modern flood basalts
(Science, 2016)How much of Earth's compositional variation dates to processes occurring during 16 planet formation remains an unanswered question. High precision W isotopic data for rocks from two large igneous provinces, the North ... -
PROGRESSIVE MICROSCOPIC DAMAGE AND THE DEVELOPMENT OF MACROSCOPIC FRACTURE IN POROUS SANDSTONES
(2011)The precursory phenomena associated with dilatancy have been extensively studied as a potential means of earthquake prediction. It is known that microstructural damage induced dilatancy precedes macroscopic failure of a ... -
A prototype miniature mass spectrometer for in situ analysis of trace elements on planetary surfaces
(2021)Interrogation of the chemical composition of rocky planets provides a deeper understanding of the history and evolution of the solar system. While laboratory studies of returned samples and remote sensing surveys of planetary ... -
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 ...