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Articles 361 - 390 of 408
Full-Text Articles in Geology
Spatial And Temporal Distribution Of Hydrothermal Minerals And Sources Of Hydrothermal Fluids Inferred From Light Stable Isotopes, Keweenaw Peninsula Native Copper District, Michigan, Thomas Bodden
Dissertations, Master's Theses and Master's Reports
Hydrothermal native copper deposits are hosted by Mesoproterozoic Midcontinent Rift-filling volcanic and sedimentary rocks in Michigan’s Keweenaw Peninsula. The genesis of the native copper deposits has been a point of interest since their discovery. Native copper and associated mineral assemblages vary temporally and spatially. A refined mineral paragenesis is presented and used as the basis to spatially compare mineral assemblages as it is essential that spatial comparison involve only minerals that are temporally/genetically, related to each other. The main-stage minerals associated with precipitation of native copper are spatially zoned. The higher-grade zones correspond to the area of native copper deposits …
Ephemeral Gully Erosion Modeling And Surveying With Close-Range Digital Photogrammetry, M. A. Islam, C. Weerasekara, Y. Zhou, A. Y. Shesukov
Ephemeral Gully Erosion Modeling And Surveying With Close-Range Digital Photogrammetry, M. A. Islam, C. Weerasekara, Y. Zhou, A. Y. Shesukov
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Exploring The Northwest Margin Of The High Plains Aquifer: Structure, Depositional History And Hydrogeology, Nebraska Geological Society Field Trip, Doug Hallum, Dennis O. Terry, Jr., Michael Leite, Jennifer Balmat
Exploring The Northwest Margin Of The High Plains Aquifer: Structure, Depositional History And Hydrogeology, Nebraska Geological Society Field Trip, Doug Hallum, Dennis O. Terry, Jr., Michael Leite, Jennifer Balmat
Conservation and Survey Division: Faculty and Staff Publications
The northwest portion of the High Plains Aquifer in Nebraska corresponds with the western Sandhills, Box Butte, Sioux and Dawes County tablelands, and the Nebraska Pine Ridge in northwest Nebraska. This field excursion will travel beyond the margins of the High Plains aquifer into the White River valley and onto the Oglala National Grasslands. These areas are not only rich in natural resources, but rich in history as well. While this excursion will explore earth history, depositional environments and a portion of the High Plains Aquifer, the authors encourage all attendees to take additional time to explore the cultural, military …
Optimizing Historic Preservation Under Climate Change: Decision Support For Cultural Resource Adaptation Planning In National Parks, Xiao Xiao, Erin Seekamp, Max Post Van Der Burg, Mitchell Eaton, Sandra Fatorić, Allie Mccreary
Optimizing Historic Preservation Under Climate Change: Decision Support For Cultural Resource Adaptation Planning In National Parks, Xiao Xiao, Erin Seekamp, Max Post Van Der Burg, Mitchell Eaton, Sandra Fatorić, Allie Mccreary
United States Geological Survey: Staff Publications
Climate change poses great challenges for cultural resource management, particularly in coastal areas. Cultural resources, such as historic buildings, in coastal areas are vulnerable to climate impacts including inundation, deterioration, and destruction from sea-level rise and storm-related flooding and erosion. However, research that assesses the trade-offs between actions for protecting vulnerable and valuable cultural resources under budgetary constraints is limited. This study focused on developing a decision support model for managing historic buildings at Cape Lookout National Seashore. We designed the Optimal Preservation Decision Support (OptiPres) model to: (a) identify optimal, annual adaptation actions for historic buildings across a 30-year …
Ecosystem Processes, Land Cover, Climate, And Human Settlement Shape Dynamic Distributions For Golden Eagle Across The Western Us, J.D. Tack, B.R. Noon, Z.H. Bowen, B.C. Fedy
Ecosystem Processes, Land Cover, Climate, And Human Settlement Shape Dynamic Distributions For Golden Eagle Across The Western Us, J.D. Tack, B.R. Noon, Z.H. Bowen, B.C. Fedy
United States Geological Survey: Staff Publications
Species–environment relationships for highly mobile species outside of the breeding season are often highly dynamic in response to the collective effects of everchanging climatic conditions, food resources, and anthropogenic disturbance. Capturing dynamic space-use patterns in a model-based framework is critical as model inference often drives place-based conservation planning. We applied dynamic occupancy models to broad-scale golden eagle Aquila chrysaetos survey data collected annually from 2006 to 2012 during the late summer post-fledging period in the western US. We defined survey sites as 10 km transect segments with a 1 km buffer on either transect side (n = 3540). Derived estimates …
Implementation Of An Occupancy-Based Monitoring Protocol For A Widespread And Cryptic Species, The New England Cottontail (Sylvilagus Transitionalis), Colin P. Shea, Mitchell J. Eaton, Darryl I. Mackenzie
Implementation Of An Occupancy-Based Monitoring Protocol For A Widespread And Cryptic Species, The New England Cottontail (Sylvilagus Transitionalis), Colin P. Shea, Mitchell J. Eaton, Darryl I. Mackenzie
United States Geological Survey: Staff Publications
Context. Designing effective long-term monitoring strategies is essential for managing wildlife populations. Implementing a cost-effective, practical monitoring program is especially challenging for widespread but locally rare species. Early successional habitat preferred by the New England cottontail (NEC) has become increasingly rare and fragmented, resulting in substantial declines from their peak distribution in the mid-1900s. The introduction of a possible competitor species, the eastern cottontail (EC),may also have played a role. Uncertainty surrounding how these factors have contributed to NEC declines has complicated management and necessitated development of an appropriate monitoring framework to understand possible drivers of distribution and dynamics.
Aims. …
Coastal Wetlands: A Synthesis, Charles S. Hopkinson, Eric Wolanski, Mark M. Brinson, Daonald R. Cahoon, Gerardo M.E. Perillo
Coastal Wetlands: A Synthesis, Charles S. Hopkinson, Eric Wolanski, Mark M. Brinson, Daonald R. Cahoon, Gerardo M.E. Perillo
United States Geological Survey: Staff Publications
What are coastal wetland ecosystems, what are their limits of distribution, and where do they exist in the overall coastal landscape? There are several general definitions for wetlands, but the Ramsar definition is likely the most broadly encompassing (http://www.ramsar. org/), whereas others are more focused definitions tailored to country-specific protection and management policies (Mitsch and Gosselink, 2006). We offer a very general approach rather than a precise definition: coastal wetlands are ecosystems that are found within an elevation gradient that ranges between subtidal depths where light penetrates to support photosynthesis of benthic plants to the landward edge where the sea …
Promoting Change In Common Tern (Sterna Hirundo) Nest Site Selection To Minimize Construction Related Disturbance., Peter C. Mcgowan, Jeffery D. Sullivan, Carl R. Callahan, William Schultz, Jennifer L. Wall, Diann J. Prosser
Promoting Change In Common Tern (Sterna Hirundo) Nest Site Selection To Minimize Construction Related Disturbance., Peter C. Mcgowan, Jeffery D. Sullivan, Carl R. Callahan, William Schultz, Jennifer L. Wall, Diann J. Prosser
United States Geological Survey: Staff Publications
Due to the many challenges facing waterbird populations (Jia et al. 2018, Wetlands International 2018), it has become common practice to limit disturbance to breeding colonies whenever possible to maximize reproductive success. While this may require often unpopular management techniques including beach closures (Jorgensen et al. 2015, Mayo et al. 2015) and predator removal (Neuman et al. 2004, Stocking et al. 2017), such actions are sometimes necessary for the success of the colony. However, there are instances when eliminating disturbance is not possible and birds must be attracted to a new site. A common method for attracting waterbirds to a …
Optimizing Historic Preservation Under Climate Change: Decision Support For Cultural Resource Adaptation Planning In National Parks, Xiao Xiao, Erin Seekamp, Max Post Van Der Burg, Mitchell Eaton, Sandra Fatorić, Allie Mccreary
Optimizing Historic Preservation Under Climate Change: Decision Support For Cultural Resource Adaptation Planning In National Parks, Xiao Xiao, Erin Seekamp, Max Post Van Der Burg, Mitchell Eaton, Sandra Fatorić, Allie Mccreary
United States Geological Survey: Staff Publications
Climate change poses great challenges for cultural resource management, particularly in coastal areas. Cultural resources, such as historic buildings, in coastal areas are vulnerable to climate impacts including inundation, deterioration, and destruction from sea-level rise and storm-related flooding and erosion. However, research that assesses the trade-offs between actions for protecting vulnerable and valuable cultural resources under bud- getary constraints is limited. This study focused on developing a decision support model for managing historic buildings at Cape Lookout National Seashore. We designed the Optimal Preservation Decision Support (OptiPres) model to: (a) identify optimal, annual adaptation actions for historic buildings across a …
Assessment Of Chronic Low-Dose Elemental And Radiological Exposures Of Biota At The Kanab North Uranium Mine Site In The Grand Canyon Watershed, Danielle Cleveland, Jo Ellen Hinck, Julia S. Lankton
Assessment Of Chronic Low-Dose Elemental And Radiological Exposures Of Biota At The Kanab North Uranium Mine Site In The Grand Canyon Watershed, Danielle Cleveland, Jo Ellen Hinck, Julia S. Lankton
United States Geological Survey: Staff Publications
High-grade U ore deposits are in various stages of exploitation across the Grand Canyon watershed, yet the effects of U mining on ecological and cultural resources are largely unknown. Wecharacterized the concentrations of Al, As, Bi, Cd, Co, Cu, Fe, Pb, Hg, Mo, Ni, Se, Ag, Tl, Th, U, and Zn, gross alpha and beta activities, and U and Th radioisotopes in soil, vegetation (Hesperostipa comata, Artemisia tridentata, Tamarix chinensis), and rodents (Peromyscus maniculatus, P. boylii) to waste material at the Kanab North mine, a mine with decades-long surficial contamination, and compared the concentrations (P<0.01) to those at a premining site (Canyon Mine). Rodent tissues were also analyzed for radium-226 and microscopic lesions. Radioactivities and some elemental concentrations (e.g., Co, Pb, U) were greater in the Kanab North mine biological samples than in Canyon Mine biota, indicating a mining-related elemental signature. Mean rodent Ra-226 (111 Bq/kg dry weight [dry wt]) was 3 times greater than expected, indicating radioactive disequilibrium. Multiple soil sample U concentrations exceeded a screening benchmark, growth inhibition thresholds for sensitive plants, and an EC20 for a soil arthropod. Lesions associated with metals exposure were also observed more frequently in rodents at Kanab North than those at Canyon Mine but could not be definitively attributed to U mining. Our results indicate that Kanab North biota have taken up U mining-related elements owing to chronic exposure to surficial contamination. However, no literature-based effects thresholds for small rodents were exceeded, and only a few soil and vegetation thresholds for sensitive species were exceeded; therefore, adverse effects to biota from U mining-related elements at Kanab North are unlikely despite chronic exposure.
Pressure, Temperature, And Stress Conditions Of Southern Alpine Fault (New Zealand) Mylonites, Jake T. Reitman
Pressure, Temperature, And Stress Conditions Of Southern Alpine Fault (New Zealand) Mylonites, Jake T. Reitman
Dissertations and Theses
The Alpine Fault, New Zealand, provides a unique window into the rheologic history of a seismically-active continental plate boundary. Due to lower exhumation rates along southern portions of the fault relative to the well-studied central Alpine Fault, deformation ages vary along strike by ~15 m.y.. Mylonites collected from two southern creeks near Haast, NZ, display a uniform recrystallized grain size of ~11 𝜇m in mylonitic quartz indicating differential stress values in the south of ~100 MPa, roughly twice the stress values observed in the central Alpine Fault. Constraints from Ti-in-quartz thermobarometry and Raman Spectroscopy of Carbonaceous Material (RSCM) indicate mylonitization …
Sequence Stratigraphy Of Middle-Mississippian Carbonates Of The Southern Appalachians: Tuscumbia Limestone, Tuscumbia, Al, Austin L. Caughey
Sequence Stratigraphy Of Middle-Mississippian Carbonates Of The Southern Appalachians: Tuscumbia Limestone, Tuscumbia, Al, Austin L. Caughey
Theses and Dissertations
This field-based research develops a sequence stratigraphic framework and detailed facies analysis which is used as a basis for understanding depositional histories of low-latitude, shallow-water, Mississippian carbonate deposits (Fort Payne Chert and Tuscumbia Limestone) in northwestern Alabama. This in turn, is used to evaluate controls on deposition (e.g., sea level, tectonics, paleogeography, and paleoceanographic conditions). Additionally, possible sources of the silica (chert) found within these units (e.g., eolian dust, upwelling) are evaluated based upon thin section analysis. Four facies and one subfacies were identified: F1: echinoderm, bryozoan mudstone/wackestone facies and Fla: muddy echinoderm chert, F2: echinoderm, bryozoan packstone/grainstone facies, F3: …
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations, Rawlings Akondi
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations, Rawlings Akondi
Graduate Theses, Dissertations, and Problem Reports (ETD)
The deep subsurface environment has been known to host microbes as early as 1926 and has also been suggested to potentially account for as much as 50% of the Earth`s biomass. Researchers have shown that microbes alter their membrane lipid components in response to physiological stress, producing stress indicative lipid biomarkers. However, little effort has been made to understand the subsurface microbial community of the shale ecosystem which is increasingly being exploited and altered by addition of drilling and hydraulic fluids to meet our growing energy needs. Phospholipid fatty acids (PLFAs) are microbial lipid biomarkers and are found in all …
Petrophysical And Geomechanical Characterization Of The Marcellus Shale In The Appalachian Basin, Yixuan Zhu
Petrophysical And Geomechanical Characterization Of The Marcellus Shale In The Appalachian Basin, Yixuan Zhu
Graduate Theses, Dissertations, and Problem Reports (ETD)
In recent years, more and more attention is paid to shale gas and hydrocarbon liquids exploration and exploitation in unconventional reservoirs. With the development of horizontal drilling and hydraulic fracturing, production from unconventional reservoirs has been greatly increased. However, not all wells, regions and basins harbor highly successful shale gas and liquids producers. In order to improve the production efficiency and reduce the cost of projects, detailed analysis needs to be undertaken to characterize the reservoir. As opposed to conventional reservoirs, extraction of gas in the unconventional reservoir is dependent not only on the reservoir quality, but also on completion …
The Petrogenesis Of The No Agua High-Silica Rhyolite In The Taos Plateau Volcanic Field, Northern New Mexico, Kevin M. Voelz
The Petrogenesis Of The No Agua High-Silica Rhyolite In The Taos Plateau Volcanic Field, Northern New Mexico, Kevin M. Voelz
Graduate Research Theses & Dissertations
The Taos Plateau volcanic field (TPVF) is located in Northern New Mexico between the eastern flanks of the Tusas Mountains and west of the Sangre de Cristo range. The TPVF is dominantly composed of basaltic lava flows, olivine andesites, and two-pyroxene dacites which erupted from 5.88 to 1.03 Ma. The variety of compositions within the field owes its origin to processes such as magma mixing, fractional crystallization, and crustal assimilation based on chemical modeling. Curiously placed within this spectrum of mafic to intermediate lavas exists the singular high-silica rhyolite of the No Agua Peaks. XRF and ICP-MS analyses from this …
Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson
Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson
Graduate Theses, Dissertations, and Problem Reports (ETD)
The Arctic Alaska–Chukotka microplate is a large Mesozoic–Cenozoic composite terrane that resides at the northern limit of the North American Cordillera. Although its Mesozoic origins are assuredly linked to the opening of the Amerasian Basin of the Arctic Ocean, its Paleozoic origins can be linked to at least three separate paleocontinents, including northern Laurentia, Baltica, and Siberia. Across the Arctic Alaska portion of the microplate, an internal, mid-Paleozoic suture zone presumably separates rocks of the North Slope subterrane (Laurentian affinity) from a collection of smaller subterranes in the southern Brooks Range and Seward Peninsula (Baltic affinity).
The mountains of the …
Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter
Determining The Precambrian Structure And Thermotectonic Evolution Of The Central Ruby Range, Southwest Montana, Sara Vivienne Stotter
Graduate Student Theses, Dissertations, & Professional Papers
The Ruby Range in southwestern Montana is a fundamental location within the Archean Wyoming craton for examining Precambrian crustal architecture and determining the thermotectonic evolution of the region. Monazite, zircon, and garnet geochronology from each of the three major units within the Ruby Range reveal two distinct metamorphic age populations: an older population ca. 2.55-2.45 Ga (the Tendoy orogeny) and a second, younger population ca. 1.78-1.72 Ga (the Big Sky orogeny). Phase equilibria modeling for the Big Sky orogeny within the confines of the Mine Gulch 7.5’ quadrangle reveal discrete pressure-temperature (P-T)histories for each of the three major …
Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway
Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway
Graduate Theses, Dissertations, and Problem Reports (ETD)
White Sands, New Mexico is the largest gypsum dune field on planet Earth, the result of reworking of gypsum deposits. The dunes have been well studied, but the Cenozoic history preceding the formation of the dune field has been poorly studied. A core drilled to a depth of 192 ft (58.5 m) beneath the modern dune field contains deposits from saline lakes, sandflats, perennial freshwater lakes, perennial brackish to saline lakes, and saline mudflats.
The core is composed of bottom-growth bedded gypsum, gypsum sandstone and siltstone, mixed siliciclastic-gypsum sandstones and siltstones, laminated siliciclastic mudstones, gypsum mudstones, and carbonate mudstones. Bottom-growth …
Application Of Lidar To 3d Structural Mapping, Bertrand Gaschot
Application Of Lidar To 3d Structural Mapping, Bertrand Gaschot
Graduate Theses, Dissertations, and Problem Reports (ETD)
The rugged, densely forested terrain of the West Virginia Appalachian Valley and Ridge Province has made it difficult for field-based studies to agree on the structure of the highly deformed Silurian-Devonian cover strata. In this study, we demonstrate a 3D approach to geologic mapping utilizing the structural information revealed in a “bare-earth” 1-m Lidar DEM of the Smoke Hole Canyon. The completed 3D map was integrated with kinematic forward modeling carried out in MOVETM to provide information on the parameters required to form the major structures observed. Additionally, land surface attributes generated using geomorphometric analysis of the Lidar allowed …
Sediment Provenance Study Of The Lower Hamilton Group: An Analysis Of The Organic-Rich Facies And Its Depositional History, Luke Patrick Fritz
Sediment Provenance Study Of The Lower Hamilton Group: An Analysis Of The Organic-Rich Facies And Its Depositional History, Luke Patrick Fritz
Graduate Theses, Dissertations, and Problem Reports (ETD)
Currently, insufficient geological models exist to explain the variability and distribution of TOC in the Marcellus Shale, within the Hamilton Group. TOC is one of the several limiting factors for natural gas production within the Marcellus Shale basin. One possible explanation for the low TOC regions is that detrital dilution was variable across the basin, with different sediment sources contributing detritus to low TOC areas, compared to surrounding regions with higher TOC. This hypothesis is tested by analyzing the source composition of inorganic detritus, using elemental and mineralogical proxies, with two cores in the Hamilton Group. The Armstrong #1 core …
Defining Historical Earthquake Rupture Parameters And Proposed Slip Distributions Through Tsunami Modeling In South-Central Chile, Alexander Dolcimascolo
Defining Historical Earthquake Rupture Parameters And Proposed Slip Distributions Through Tsunami Modeling In South-Central Chile, Alexander Dolcimascolo
All Master's Theses
Reliable tsunami early warning forecasts rely on accurate initial modeling conditions and interpretations of subduction zone behavior in a multi-century perspective. GPS and seismologic data were introduced this past century to study rupture dynamics in detail, however limited information is known about ruptures that pre-date the 20th century. I propose a methodology that uses statistics to better understand these pre-20th century ruptures. This methodology applies the historical and geologic tsunami record as a means to select a suite of tsunami simulations from earthquake source solutions. I chose south-central Chile (46°S to 30°S) to test this new methodology; it …
Utilizing Radiolarian Assemblages To Track Changes In The Agulhas Current Through The Mid-Pleistocene Transition: Iodp Site U1479, William Alberto Bugbee
Utilizing Radiolarian Assemblages To Track Changes In The Agulhas Current Through The Mid-Pleistocene Transition: Iodp Site U1479, William Alberto Bugbee
Graduate Research Theses & Dissertations
The objective of this study was to assess the radiolarian assemblage of the Agulhas Current at International Ocean Discovery Program Expedition 361, Site U1479 (the most westward site), through the Mid-Pleistocene Transition (MPT). Samples between 1,000 to 777ka were utilized to (1) characterize the radiolarian assemblage, (2) observe whether the radiolarian assemblage is sufficiently distinctive to help discern the occurrence of the MPT in the Southern Ocean, and (3) determine whether changes in the radiolarian assemblage reflect a change or changes in ocean currents that may have occurred during the MPT.
Over 300 radiolarian species from 15 different families were …
Textile Dyes As A Source Of Groundwater Contamination In Mandalay, Myanmar, Surya Freeman
Textile Dyes As A Source Of Groundwater Contamination In Mandalay, Myanmar, Surya Freeman
Graduate Research Theses & Dissertations
Textile dyeing and weaving of traditional longyi garments has traditionally occurred in the Amarapura Township of Mandalay, Myanmar, since 1822, transitioning from natural to chemical dyes in the early 1900’s. With no current wastewater treatment facilities in Mandalay, dye effluents mix with other wastewaters in unlined canals dug near peoples’ homes and discharge into local canals and groundwater. As locals rely heavily on dug and tube wells for drinking, bathing, and cooking, this industry poses a major health hazard to the people in this region. The objective of this study is to identify the previously unknown composition of the textile …
Water Quality And Small Unmanned Aerial System Photogrammetry Of Boeng Cheung Ek Wastewater Treatment Wetland, Phnom Penh, Cambodia, Samuel Vesal Mallow
Water Quality And Small Unmanned Aerial System Photogrammetry Of Boeng Cheung Ek Wastewater Treatment Wetland, Phnom Penh, Cambodia, Samuel Vesal Mallow
Graduate Research Theses & Dissertations
Boeng Cheung Ek wetland is a large, peri-urban, free water surface, natural wastewater treatment wetland that services approximately 90% of combined storm water and untreated sewage from the city of Phnom Penh, Cambodia, population over 1.5 million. Due to monsoon rainfall and connectivity to the Mekong River, the wetted area cycles between 13 km2 and 20 km2 annually. The objective of this study is to characterize the spatiotemporal variability of contaminants in wetland surface water and groundwater. Dissolved ions including ammonium, nitrate-N (as NO3), phosphate, and chloride, along with E. coli, trace metals, δH, δ18O, and physicochemical parameters were determined …
Hydrogeochemical Characterization Of Yalahau Region, Mexico, Jessica Leann Mckay
Hydrogeochemical Characterization Of Yalahau Region, Mexico, Jessica Leann Mckay
Graduate Research Theses & Dissertations
The Yalahau Region, located in the northeastern portion of the Yucatán Peninsula, hosts a series of elongated depressions trending north/south in the direction of Isla Holbox, identified as the Holbox Fracture Zone. Previous studies have explored the geomorphology and various hydrologic characteristics of the Yucatán Peninsula; however, there is a paucity of data concerning the interior region where the fractures are located. Strontium isotope and major ion geochemistry data of the surface water and groundwater of this region serves as a hydrogeochemical fingerprint, aiding to constrain the hydrological boundaries, determining flow paths, and characterizing hydrogeochemical processes that impact the composition …
A Soil Genesis Investigation Into Possible Long-Range Transport Of Foreign Sediments In The Stann Creek District Of Belize, Heath Sawyer
A Soil Genesis Investigation Into Possible Long-Range Transport Of Foreign Sediments In The Stann Creek District Of Belize, Heath Sawyer
Cal Poly Humboldt theses and projects
Throughout the world, long range transport (LRT) of aeolian dust plays a major role in the total global dust budget. Research suggests that LRT dust from the deserts of North Africa play a role in soil genesis in the Americas. The focus of this study is a preliminary investigation for evidence of North African dust or volcanic ash influence on the soils in the Cockscomb Basin Wildlife Sanctuary in Stann Creek District, Belize. A series of 7 soil profiles were analyzed from a catena transect to determine if there is evidence of foreign materials by using X-ray diffraction and Scanning …
Origin Of Periclines In The Ozark Plateau, Missouri: A Field And Numerical Modeling, Chao Liu
Origin Of Periclines In The Ozark Plateau, Missouri: A Field And Numerical Modeling, Chao Liu
Doctoral Dissertations
"A series upright sub-horizontal folds in sandstones of the early Ordovician Roubidoux Formation are exposed in road cuts along US Highway 63 in the northern part of the Salem Plateau of central Missouri for over a distance of approximately 10 km. These folds are in marked contrast to the more typical horizontal to sub-horizontal Ordovician strata of the Ozark Plateau. The origin of those folds remains enigmatic. The inspection of the characteristics of these folds using stereographic analysis revealed a non-cylindrical geometrical pattern than a near cylindrical fold. Structural data of 54 folds indicate an alternating basin and dome pattern. …
Provenance, Redox Conditions, And Diagenesis Of Shales In Chang 7 Member Of Upper Triassic Yanchang Formation, Ordos Basin, China, Bin Sun
Doctoral Dissertations
“This study aims to decipher provenance, redox conditions, and burial history of shales in Chang 7 Member of Upper Triassic Yanchang Formation, Ordos Basin, China. The first paper discusses the origins of single-channeled, vertical, sinuous, and calcite-bitumen-filled cracks in the shales. Results show that in early diagenesis, unconsolidated mud was expanded open by escaping gases produced during organic matter maturation under hydrothermal influences. Calcite initially filled the cracks; bitumen and pyrite came in later and occupied the cracks in various ways. Compaction occurred next and folded the calcite- and bitumen-filled cracks into sinuous shapes. The second paper uses geochemical and …
Paleoenvironment And Paleoclimate Of Ne Pangea In Early Permian-Linking Chemo- And Cyclo-Stratigraphy, Bogda Mountains, Nw China, Xin Zhan
Doctoral Dissertations
"The overall objective of this study is to understand physical and chemical responses of Earth Systems to environmental and climatic perturbations of diverse magnitudes and time scales in Bogda Mountains, NE Pangea. Field investigations, petrographic observations, and geochemical analyses have been used to interpret paleoenvironment and paleoclimate in cm-m-scale high-order cycles (HCs: 0.1-100 kyrs), low-order cycles (LCs: 1-10 Myr), and critical events of late Paleozoic ice age (LPIA: 320-260 Myr ago). Four organo-facies are one-to-one correlated with the four lithofacies in the meter-scale HCs, suggesting litho- and organo-facies are genetically linked and fundamentally controlled by environmental changes associated with lake …
Fault Imaging Enhancement In Taranaki Basin, New Zealand And Rock Physics And Inversion Based Reservoir Characterization In The Central Gulf Coast Region Of Texas, Tianze Zhang
Doctoral Dissertations
"Fault imaging technique and reservoir characterization based on rock physics analysis and pre-stack inversion has been widely used hydrocarbon exploration. For the fault imaging technique, the ant tracking has been widely used in fault interpretation. However, the reliability of the results is highly dependent on appropriately choosing a signal processing method and volume attributes. In our study area, which lies in the southern Taranaki Basin, we applied Graphic Equalizer as the processing tool and the Chaos attribute before running the ant tracking algorithm. Results show that the procedure provides a better result and can map both the major and minor …