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Articles 361 - 390 of 1044
Full-Text Articles in Earth Sciences
Umphlett Qci June 2014, Natalie Umphlett
Umphlett Qci June 2014, Natalie Umphlett
High Plains Regional Climate Center: Staff Publications
Highlights for the Basin
Temperature and Precipitation Anomalies
Streamflow
Drought Impacts to Livestock
Continued Cold Hampers Producers in North
3-Month Precipitation and Temperature Outlooks
U.S. Seasonal Drought Outlook
Sex-Biased Gene Flow Among Elk In The Greater Yellowstone Ecosystem, Brian K. Hand, Shanyuan Chen, Neil Anderson, Albano Beja-Pereira, Paul C. Cross, Michael Ebinger, Hank Edwards, Robert A. Garrott, Marty D. Kardos, Matt Kauffman, Erin L. Landguth, Arthur Middleton, Brandon Scurlock, P.J. White, Pete Zager, Michael K. Schwartz, Gordon Luikart
Sex-Biased Gene Flow Among Elk In The Greater Yellowstone Ecosystem, Brian K. Hand, Shanyuan Chen, Neil Anderson, Albano Beja-Pereira, Paul C. Cross, Michael Ebinger, Hank Edwards, Robert A. Garrott, Marty D. Kardos, Matt Kauffman, Erin L. Landguth, Arthur Middleton, Brandon Scurlock, P.J. White, Pete Zager, Michael K. Schwartz, Gordon Luikart
United States Geological Survey: Staff Publications
We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST = 0.161; P = 0.001) compared to genetic differentiation for nuclear microsatellite data (FST = 0.002; P = 0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female …
The Bell Springs Formation: Characterization And Correlationof Upper Triassic Strata In Northeast Utah, Skyler Bart May
The Bell Springs Formation: Characterization And Correlationof Upper Triassic Strata In Northeast Utah, Skyler Bart May
Theses and Dissertations
Upper Triassic strata that lie between the Chinle Formation and Nugget Sandstone along the south flank of the Uinta Mountains in northeastern Utah are distinctive. In the past, these rocks have been lumped together with the overlying or underlying units. These strata are equivalent to the Bell Springs Member of the Nugget Sandstone as defined in Wyoming and perhaps to the Rock Point Formation of the Chinle Formation near the Four Corners region. In this study, these rocks will be called the Bell Springs Formation following the usage of Lucas (1993) in Wyoming. The unit is regionally mappable in northeastern …
Correlation And Paleoenvironments Above West T9.3 Tuff, Pisco Formation, Peru, Caleb Stanton
Correlation And Paleoenvironments Above West T9.3 Tuff, Pisco Formation, Peru, Caleb Stanton
Loma Linda University Electronic Theses, Dissertations & Projects
The Pisco Basin is a Cenozoic forearc basin in west central Peru. Though outcrops are well exposed, contain little diagenetic overprint, or complex structural deformation, only rudimentary correlations between outcrops are published and no attempts have been made to define time-bounded subunits. The goal of this study is to develop high resolution-stratigraphy and paleoenvironmental interpretations for a time-bounded unit in the lower part of the Miocene Pisco Formation. In this study, we correlated, mapped, and dated a tuff couplet and associated beds over 25 km2. We measured eight sections that include the tuffs and conducted detailed facies analysis. Sections were …
Late Quaternary Faulting History Of The Carrizal And Related Faults, La Paz Region, Baja California Sur, Mexico, Paul J. Umhoefer, Sara J. Maloney, Beverly Buchanan, J. Ramón Arrowsmith, Genaro Martinez-Gutiérrez, Graham Kent, Neal Driscoll, Alistair Harding, Darrell Kaufman, Tammy M. Rittenour
Late Quaternary Faulting History Of The Carrizal And Related Faults, La Paz Region, Baja California Sur, Mexico, Paul J. Umhoefer, Sara J. Maloney, Beverly Buchanan, J. Ramón Arrowsmith, Genaro Martinez-Gutiérrez, Graham Kent, Neal Driscoll, Alistair Harding, Darrell Kaufman, Tammy M. Rittenour
Geosciences Faculty Publications
The southwest margin of the Gulf of California has an array of active normal faults despite this being an oblique-divergent plate boundary with spreading centers that localized deformation along the plate boundary 2–3 million years ago. The Carrizal and Centenario faults form the western border fault of the Gulf of California marginal fault system within and south of La Paz Bay, and ∼20–30 km west of the capital city of La Paz, Baja California Sur, Mexico. Geologic and geomorphic mapping, optically stimulated luminescence (OSL) geochronology, and paleoseismic investigations onshore, compressed high-intensity radar pulse (CHIRP) profiling offshore, and analysis of uplifted …
Predictive Modeling In The Search For Vertebrate Fossils: Geographic Object Based Image Analysis (Geobia) In The Eocene Of Wyoming, Bryan Bommersbach
Predictive Modeling In The Search For Vertebrate Fossils: Geographic Object Based Image Analysis (Geobia) In The Eocene Of Wyoming, Bryan Bommersbach
Masters Theses
The development and testing of predictive models for identifying productive fossil localities represents a promising interdisciplinary endeavor among geographic information scientists, paleoanthropologists, and vertebrate paleontologists. This thesis analyzed high resolution (2m spatial resolution) commercial satellite imagery from the Worldview-2 satellite of five areas of the Great Divide Basin using a GEographic Object-Based Image Analysis (GEOBIA) technique, which segments the image into spectrally homogeneous, multi-pixel image objects. In addition to allowing statistical analysis of the spectral characteristics of the image objects, GEOBIA techniques also let analysts incorporate expert knowledge and contextual information to improve classification accuracy. The spectral characteristics of the …
A Seasonally Modulated Earthquake Swarm Near Maupin, Oregon, Jochen Braunmiller, John L. Nabelek, Anne M. Trehu
A Seasonally Modulated Earthquake Swarm Near Maupin, Oregon, Jochen Braunmiller, John L. Nabelek, Anne M. Trehu
School of Geosciences Faculty and Staff Publications
From December 2006 to November 2011, the Pacific Northwest Seismic Network (PNSN) reported 467 earthquakes in a swarm 60 km east of Mt Hood near the town of Maupin, Oregon. The swarm included 20 MD ≥ 3.0 events, which account for over 80 per cent of the cumulative seismic moment release of the sequence. Relocation of 45 MD≥ 2.5 earthquakes and moment tensor analysis of nine 3.3 ≤ Mw ≤ 3.9 earthquakes reveals right-lateral strike-slip motion on a north-northwest trending, 70° west dipping, 1 km2 active fault patch at about 17 km depth. The swarm started …
Sedimentological And Stratigraphic Study Of A Falling-Stage Delta Complex In The Upper Cretaceous (Turonian) Ferron Sandstone Member Of The Mancos Shale, South-Central Utah, Usa, Fares Alaboud
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The character and distribution of lithofacies in falling-stage deltas are incompletely documented. This paper presents a sedimentological and stratigraphic evaluation of a superbly-exposed interval of Cretaceous deltaic strata that are believed to be of falling stage origin. The studied interval forms part of the Upper Cretaceous (Turonian) Ferron Sandstone Member of the Mancos Shale in the southernmost Henry Mountains Basin of south-central Utah, USA. The interval of interest is exposed in three dimensions over a 20 km2 area in a series of canyon walls. Observed facies include fine-grained mudrocks (offshore basin), mudrocks with thinly interlaminated sandstone (prodelta), thinly interbedded …
Watershed And Aquatic Ecosystem Evolution During The Late-Glacial And Early-Holocene Inferred From High-Resolution Diatom And Geochemical Records In The Yellowstone Region, Yanbin Lu
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
High-resolution diatom records spanning the late-glacial and early-Holocene were developed from three lakes in the Yellowstone region to infer the lake history and to evaluate the relative importance of climatic versus non-climatic factors on the aquatic ecosystem evolution. Synchronous shifts in diatom community structure occurred in all lakes, which are located in regions of varied surficial geology and precipitation seasonality, in the intervals of 13.9-13.8, 13.2-13.1, 11.3-11.0 and 8.8-8.7 cal ka. The synchronous diatom community structure shifts suggest that large-scale climatic change is the primary driver of the aquatic ecosystem evolution in this region, whereas the influence of non-climatic factors …
Origin And Distribution Of The Mississippian–Pennsylvanian Boundary Unconformity In Marine Carbonate Successions With A Case Study Of The Karst Development Atop The Madison Formation In The Bighorn Basin, Wyoming, Lucien Nana Yobo
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
The causal mechanism of the widespread unconformity that encompasses the Mississippian – Pennsylvanian boundary remains poorly understood. This unconformity, first thought to be restricted to North America, is now known to be present in other regions of the globe. Possible causes for the unconformity include (1) sea level draw down from the onset of glaciation at start of the late Paleozoic ice age and (2) increased tectonic activity from the formation of the supercontinent of Pangea. Thus the origin of the unconformity is still poorly constrained.
This study examines possible causal mechanisms for the widespread unconformity that encompasses the Mississippian …
Geochemistry Of The Great Valley Group: An Integrated Provenance Record, Kathleen D. Surpless
Geochemistry Of The Great Valley Group: An Integrated Provenance Record, Kathleen D. Surpless
Earth and Environmental Geosciences Faculty Research
Sedimentary geochemistry of fine-grained strata of the Great Valley Group (GVG) in California documents a provenance signal that may better represent unstable, mafic minerals and volcanic clasts within sediment source regions than the provenance signal documented in the petrofacies and detrital zircon analysis of coarser sedimentary fractions. Geochemistry of the GVG provides an overall provenance framework within which to interpret sandstone petrofacies and detrital zircon age signatures. The geochemical signature for all Sacramento Valley samples records an overall continental arc source, with significant variation but no clear spatial or temporal trends, indicating that the geochemical provenance signal remained relatively consistent …
Co2 Sequestration Test In A Deep, Unminable Lignite Seam, University Of North Dakota. Energy And Environmental Research Center
Co2 Sequestration Test In A Deep, Unminable Lignite Seam, University Of North Dakota. Energy And Environmental Research Center
EERC Brochures and Fact Sheets
Fact sheet describing results of a Plains CO2 Reduction (PCOR) Partnership-implemented test to determine the possibility of storing CO2 in unminable lignite seams. Discusses testing procedure and purpose, and summarizes key results. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]
Water In The 21st Century, Grayson Michael Shor
Water In The 21st Century, Grayson Michael Shor
Social Sciences
The aim of this research project is to provide a comprehensive and global analysis of water use in order to provide the reader with a comprehensive grasp of current and impending issues. The included five (5) chapters discuss water distribution, conservation, purification, law, international development, economic debates, ethical consideration, as well as educated estimations of the effects water related issues may cause in the next one-hundred years.
Late Holocene Dune Development And Shift In Dune-Building Winds Along Southern Lake Michigan, Zoran Kilibarda, Ryan Venturelli, Ronald J. Goble
Late Holocene Dune Development And Shift In Dune-Building Winds Along Southern Lake Michigan, Zoran Kilibarda, Ryan Venturelli, Ronald J. Goble
Department of Earth and Atmospheric Sciences: Faculty Publications
The youngest dune belt along Lake Michigan’s southern coast evolved through four stages. The first stage began during the Nipissing transgression, ~6.0 ka, and culminated at the Nipissing high, ~4.5 ka. Rising lake levels eroded the lake margins and generated sediment that was transported to southern Lake Michigan, creating the Tolleston barrier beach. The second stage, beginning ~4.5 ka with a rapid lake level fall and continuing to ~3.0 ka, represents a major episode of transgressive parabolic dune field development. Large, simple parabolic dunes, with easterly apices (85–105° azimuth) suggestive of westerly wind formation, developed in a sand belt ~1–2 …
The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke
The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke
Department of Biochemistry: Faculty Publications
Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O2-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O2 in the biosphere is considered to have been extremely low as compared with present-day values. Therefore the evolutionary histories of life and of O2-levels are likely intricately intertwined. The obvious biological proxy for inferring the impact of changing O2-levels on life is the evolutionary history …
Stratigraphic Framework And Landsystem Correlation For Deposits Of The Saginaw Lobe, Michigan, Usa, Ivan R. Guzman
Stratigraphic Framework And Landsystem Correlation For Deposits Of The Saginaw Lobe, Michigan, Usa, Ivan R. Guzman
Masters Theses
Since the time of the Last Glacial Maximum (LGM) the south-central portion of the Lower Michigan Peninsula has been subject to several glacial advances and retreats by the Saginaw lobe. As part of the U.S Geological Survey Great Lakes Geological Mapping Coalition projects, several rotosonic borings were drilled between 2006 and 2013 in Barry, Kalamazoo and Calhoun Counties. Gamma ray logs and textural analyses were completed for each core. Five of these borings were selected according to their diamicton (till) content and correlated using water well logs and surficial geology maps. Glacial deposits such as diamicton serve as evidence of …
The Capacity Of Hydrous Fluids To Transport And Fractionate Incompatible Elements And Metals Within The Earth's Mantle, John Adam, Marek Locmelis, Juan Carlos Afonso, Tracy Rushmer, Marco L. Fiorentini
The Capacity Of Hydrous Fluids To Transport And Fractionate Incompatible Elements And Metals Within The Earth's Mantle, John Adam, Marek Locmelis, Juan Carlos Afonso, Tracy Rushmer, Marco L. Fiorentini
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Both silicate melts and aqueous fluids are thought to play critical roles in the chemical differentiation of the Earth's crust and mantle. Yet their relative effects are poorly constrained. We have addressed this issue by measuring partition coefficients for 50 trace and minor elements in experimentally produced aqueous fluids, coexisting basanite melts, and peridotite minerals. The experiments were conducted at 1.0-4.0 GPa and 950-1200°C in single capsules containing (either 40 or 50 wt %) H2O and trace element-enriched basanite glass. This allowed run products to be easily identified and analyzed by a combination of electron microprobe and LAM-ICP-MS. …
Exploring The Link Between Otolith Growth And Function Along The Biological Continuum In The Context Of Ocean Acidification, Eric D. Wilcox Freeburg
Exploring The Link Between Otolith Growth And Function Along The Biological Continuum In The Context Of Ocean Acidification, Eric D. Wilcox Freeburg
Graduate Doctoral Dissertations
Oceans are acidifying as atmospheric CO2 is drawn down. This process, known as ocean acidification (OA), is well known and documented. Over the next 100 years, pH of the surface ocean is projected to decrease by up to 0.35 units. This CO2 draw down has a direct effect on dissolved inorganic carbon (DIC) balance in the ocean. OA is expected to impact calcifying organisms that rely on constituencies of the DIC system, specifically carbonate ion [CO32-]. It is clear that externally calcified structures, such as coral skeletons, bivalve shells, etc., will be significantly affected as pH, …
The Effects Of Cold Adaptation On The Growth And Development Of The Neandertal Cranial Base, Sarah Caldwell
The Effects Of Cold Adaptation On The Growth And Development Of The Neandertal Cranial Base, Sarah Caldwell
Theses and Dissertations
Neandertals and modern humans possess very different craniofacial shapes. Some recent work has attributed these contrasting shapes specifically to differences in brain development, which are extrapolated to mean differences in cognitive function. However, this may not necessarily be the case. In this paper, it is suggested that a size increase in the cranial base and rapid cranial growth are due not to cognitive differences, but environmental factors, specifically Neandertal adaptation to cold. Adaptation to cold would not only explain the more rapid growth of the Neandertal cranium, but also elongation of the cranial base via elongation of the nasopharynx for …
Induced Seismicity Of Central Arkansas, Najah Abd
Induced Seismicity Of Central Arkansas, Najah Abd
Theses and Dissertations
Enola area is known to generate swarms of earthquakes that are clustered in space and time. The remarkable swarm of the early 80s generated thousands of earthquakes many of them were felt by people lived in the area. More recently, a magnitude 4.4 earthquake took place on May 4, 2001 in the area which was followed by thousands of recorded earthquakes. The main shock was felt widely in the region including the city of Little Rock. On February 27, 2011, North Central Arkansas area was shaken by an earthquake of magnitude 4.7. This earthquake was the biggest to be registered …
Exposure To Residual Concentrations Of Elements From A Remediated Coal Fly Ash Spill Does Not Adversely Influence Stress And Immune Responses Of Nestling Tree Swallows, Michelle L. Beck, William A. Hopkins, John J. Hallagan, Brian P. Jackson, Dana M. Hawley
Exposure To Residual Concentrations Of Elements From A Remediated Coal Fly Ash Spill Does Not Adversely Influence Stress And Immune Responses Of Nestling Tree Swallows, Michelle L. Beck, William A. Hopkins, John J. Hallagan, Brian P. Jackson, Dana M. Hawley
Dartmouth Scholarship
Anthropogenic activities often produce pollutants that can affect the physiology, growth and reproductive success of wildlife. Many metals and trace elements play important roles in physiological processes, and exposure to even moderately elevated concentrations of essential and non-essential elements could have subtle effects on physiology, particularly during development. We examined the effects of exposure to a number of elements from a coal fly ash spill that occurred in December 2008 and has since been remediated on the stress and immune responses of nestling tree swallows. We found that nestlings at the site of the spill had significantly greater blood concentrations …
U.S. Drought Monitor, May 27, 2014, Michael J. Brewer
U.S. Drought Monitor, May 27, 2014, Michael J. Brewer
United States Agricultural Commodities in Drought Archive
Drought map of U.S. for May 27, 2014 (5/27/14) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.
Geophysical Applications For Levee Assessment, Hussein Khalefa Chlaib
Geophysical Applications For Levee Assessment, Hussein Khalefa Chlaib
Theses and Dissertations
Levees are important engineering structures that build along the rivers to protect the human lives and shield the communities as well as agriculture lands from the high water level events. Animal burrows, subsurface cavities, and low density (high permeability) zones are weakness features within the levee body that increase its risk of failure. To prevent such failure, continuous monitoring of the structure integrity and early detection of the weakness features must be conducted. Application of Ground Penetrating Radar (GPR) and Capacitively Coupled Resistivity (CCR) methods were found to be very effective in assessing the levees and detect zones of weakness …
Dust Mediated Transfer Of Phosphorus To Alpine Lake Ecosystems Of The Wind River Range, Wyoming, Usa, Janice Brahney, Ashley P. Ballantyne, P. Kociolek, Sarah A. Spaulding, Megan Otu, T. Porwoll, Jason C. Neff
Dust Mediated Transfer Of Phosphorus To Alpine Lake Ecosystems Of The Wind River Range, Wyoming, Usa, Janice Brahney, Ashley P. Ballantyne, P. Kociolek, Sarah A. Spaulding, Megan Otu, T. Porwoll, Jason C. Neff
Watershed Sciences Faculty Publications
Alpine lakes receive a large fraction of their nutrients from atmospheric sources and are consequently sensitive to variations in both the amount and chemistry of atmospheric deposition. In this study we explored the spatial changes in lake water chemistry and biology along a gradient of dust deposition in the Wind River Range, Wyoming. Regional differences were explored using the variation in bulk deposition, lake water, sediment, and bedrock geochemistry and catchment characteristics. Dust deposition rates in the Southwestern region averaged 3.34 g m−2 year−1, approximately three times higher than deposition rates in the Northwestern region (average 1.06 g m−2 year−1). …
Upper Mantle Seismic Anisotropy Beneath The West Antarctic Rift System And Surrounding Region From Shear Wave Splitting Analysis, Natalie J. Accardo, Douglas A. Wiens, Stephen Hernandez, Richard C. Aster, Andrew Nyblade, Audrey D. Huerta, Sridhar Anandakrisnan, Terry Wilson, David S. Heeszel, Ian W.D. Dalziel
Upper Mantle Seismic Anisotropy Beneath The West Antarctic Rift System And Surrounding Region From Shear Wave Splitting Analysis, Natalie J. Accardo, Douglas A. Wiens, Stephen Hernandez, Richard C. Aster, Andrew Nyblade, Audrey D. Huerta, Sridhar Anandakrisnan, Terry Wilson, David S. Heeszel, Ian W.D. Dalziel
Geological Sciences Faculty Scholarship
We constrain azimuthal anisotropy in the West Antarctic upper mantle using shear wave splitting parameters obtained from teleseismic SKS, SKKS and PKS phases recorded at 37 broad-band seismometres deployed by the POLENET/ANET project. We use an eigenvalue technique to linearize the rotated and shifted shear wave horizontal particle motions and determine the fast direction and delay time for each arrival. High-quality measurements are stacked to determine the best fitting splitting parameters for each station. Overall, fast anisotropic directions are oriented at large angles to the direction of Antarctic absolute plate motion in both hotspot and no-net-rotation frameworks, showing that the …
U.S. Drought Monitor, May 20, 2014, Michael J. Brewer
U.S. Drought Monitor, May 20, 2014, Michael J. Brewer
United States Agricultural Commodities in Drought Archive
Drought map of U.S. for May 20, 2014 (5/20/14) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.
Geochemistry, Mineralogy And Evolution Of Mica And Feldspar From Within The Mount Mica Pegmatite, Maine, Usa, Karen L. Marchal
Geochemistry, Mineralogy And Evolution Of Mica And Feldspar From Within The Mount Mica Pegmatite, Maine, Usa, Karen L. Marchal
LSU New Orleans Theses and Dissertations
Mount Mica is a poorly zoned sodic LCT-type pegmatite consisting dominantly of quartz, albite and muscovite in the outer portions. Potassium feldspar and lepidolite are restricted to the core zone. Micas in the wall zone are chemically homogeneous, but abruptly evolve into higher Cs + Rb bearing lithian muscovites and lepidolites in the core zone. The abrupt increase of the Cs, Rb in K-feldspar, and Cs, Rb and F in muscovite, and lepidolite combined with the occurrence of highly evolved species lepidolite, pollucite, elbaite, beryl and spodumene in the core zone suggests that incompatible elements were retained in residual …
Mineralogy And Geochemistry Of The Erongo Granite And Interior Quartz-Tourmaline Orbicules And Nyf-Type Miarolitic Pegmatites, Namibia, Andrew P. Boudreaux
Mineralogy And Geochemistry Of The Erongo Granite And Interior Quartz-Tourmaline Orbicules And Nyf-Type Miarolitic Pegmatites, Namibia, Andrew P. Boudreaux
LSU New Orleans Theses and Dissertations
The early Cretaceous anorogenic Erongo Granite of Namibia is known to host abundant boron mineralization in rounded, quartz-tourmaline clusters and in NYF-type miarolitic, pegmatitic cavities. Rock and mineral samples were taken from the bulk granite, tourmaline nests, and miarolitic cavities and analyzed using a variety of modern analytical techniques. Geochemical and mineralogical data suggest substantial input from the metasedimentary rocks of the Damara orogen was important in the genesis of the Erongo Granite magma. The geochemical signature of the Damara orogen is most evident in the tourmaline clusters and miarolitic cavities, where fractional crystallization accumulated volatile and incompatible elements enough …
Contact Zone Mineralogy And Geochemistry Of The Mt. Mica Pegmatite, Oxford County, Maine, Kimberly T. Clark
Contact Zone Mineralogy And Geochemistry Of The Mt. Mica Pegmatite, Oxford County, Maine, Kimberly T. Clark
LSU New Orleans Theses and Dissertations
This study focuses on exocontact mineral assemblages to determine composition, thermal signatures, and the extent of exomorphism that occurred between the Mt. Mica pegmatite and the migmatite host rock at the contact. Biotite-garnet thermometry of country rock samples resulted in an average temperature estimate of 630 °C. Measured biotite Fe/(Fe+Mg) ratios were used to calculate an fO2 of -18. The results indicate that the country rock and pegmatite formed under similar oxidizing conditions near the quartz-fayalite-magnetite (QFM) equilibria buffer. Whole rock (REE) analysis indicates an interaction trend between the country rock and pegmatite. Exomorphism does not appear to have …
An Analysis Of The Green Knoll Salt Dome, Located In The Southeast Green Canyon, Deep Water Gulf Of Mexico, Randal J. Broussard
An Analysis Of The Green Knoll Salt Dome, Located In The Southeast Green Canyon, Deep Water Gulf Of Mexico, Randal J. Broussard
LSU New Orleans Theses and Dissertations
The western portion of the Mississippi/Atwater fold belt in the Gulf of Mexico contains what is known as The Green Knoll Salt Dome. The creation and growth of this salt diapir is punctuated by salt deposition, salt migration, sediment loading, and is linked to the “Frampton” fold belt. An indicator of these growth periods is exhibited in an angular unconformity (halo-kinetic sequence boundary) that flanks the diapir. This unconformity developed during the Miocene-Pliocene chronostratigraphic boundary. The “Redwood” (Green Canyon 1001) prospect was drilled after the discovery of middle Miocene sands containing hydrocarbons in the Mad Dog field (GC 826). The …