Open Access. Powered by Scholars. Published by Universities.®

Geology Commons™

Open Access. Powered by Scholars. Published by Universities.®

29,942 Full-Text Articles 16,130 Authors 6,782,393 Downloads 178 Institutions

All Articles in Geology

Faceted Search

29,942 full-text articles. Page 1120 of 1248.

Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins 2017 Utah State University

Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

What effect does the development of oil and gas have on the observed air quality (i.e., increased ozone, carbon dioxide (CO2), volatile organic compounds (VOCs), and/or methane emissions) in northeastern Utah? What percentage of these gases is natural background emissions, and what percentage is due to the recent oil and gas development in the region? Emissions in this text refer to gases released from the earth’s surface to the atmosphere. Methane is the primary compound in natural gas. Natural gas is a naturally occurring hydrocarbon gas mixture. Emissions of methane, non-methane hydrocarbons (NMHC), and CO2 at 27 …


Comparison Of Flow Dynamics And Bifurcation Angles In Tributary And Distributary Channel Networks, Thomas Coffey 2017 University of Arkansas, Fayetteville

Comparison Of Flow Dynamics And Bifurcation Angles In Tributary And Distributary Channel Networks, Thomas Coffey

Graduate Theses and Dissertations

The dynamics of channel mouth bifurcations on river deltas can be understood using theory developed in tributary channel networks. Bifurcations in groundwater-fed tributary networks have been shown to evolve dependent on diffusive ground water flow patterns

directly adjacent to the channel network, producing a critical angle of 72°. We test the hypothesis that bifurcation angles in distributary channel networks are likewise dictated by a diffusive external flow field, in this case the shallow surface water surrounding the subaqueous portion of distributary channels in a deltaic setting. We measured 25 unique distributary bifurcations in an experimental delta and 197 bifurcations in …


Environmental Changes Across The Early Mississippian Carbon Isotope Excursion, Dev Krishna Maharjan 2017 University of Nevada, Las Vegas

Environmental Changes Across The Early Mississippian Carbon Isotope Excursion, Dev Krishna Maharjan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Early Mississippian K–O (Kinderhookian-Osagean) δ13C excursion or TICE (mid-Tournaisian carbon isotope excursion) is characterized by an anomalous carbonate carbon isotope value of ≥5‰ that has been documented from numerous stratigraphic sections across the globe. This δ13C excursion coincides with global cooling and sea-level fall and predicts a significant change in seawater chemistry. However, sulfate sulfur isotope data across the K-O δ13C excursion reported in previous studies seem not to be responsive to the carbon cycle. Likewise, a recent study has documented a unidirectional increase in nitrogen isotopes across this excursion, which is not anticipated considering the amount of organic …


An Elemental Highway: Investigation Of A High Nickel Anomaly In Olivine From The Island Of Niihau, Hawaii, Alexander James Valentine 2017 University of Nevada, Las Vegas

An Elemental Highway: Investigation Of A High Nickel Anomaly In Olivine From The Island Of Niihau, Hawaii, Alexander James Valentine

UNLV Theses, Dissertations, Professional Papers, and Capstones

The study of volcanic geochemistry is one of the main gateways for investigating the Earth’s mantle. One important topic in the field is that of nickel (Ni) in the mineral olivine. While Ni is a compatible element in olivine, its high concentration at a given MgO content is not well understood. A variety of hypotheses have been proposed, including attributing presence of Ni to pyroxenite source melting, contribution from the core, or variation in peridotite source melting. In addition to the other hypotheses, chemical diffusion may also be a mechanism for enriching olivine Ni concentration. Magnesium-iron (Mg-Fe) isotopic measurements have …


Magmatic Evolution Of Early Subduction Zones: Geochemical Modeling And Chemical Stratigraphy Of Boninite And Fore Arc Basalt From The Bonin Fore Arc, Emily A. Haugen 2017 Utah State University

Magmatic Evolution Of Early Subduction Zones: Geochemical Modeling And Chemical Stratigraphy Of Boninite And Fore Arc Basalt From The Bonin Fore Arc, Emily A. Haugen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Izu-Bonin-Mariana arc stretches south from Japan to Guam in the Western Pacific. International Ocean Discovery Project Expedition 352 drilled four core in the fore arc of the Izu-Bonin arc east of the Bonin Islands: U1439C, U1440B, U1441A, and U1442A. From the four core, 124 samples were retrieved and analyzed for major and trace elements. Two main rock types were identified: FAB and boninite. FAB is a Mid-Ocean Ridge Basalt (MORB)-like tholeiite with variable fluid mobile element enrichment such as Rb, Ba, and Sr, and low Ti/V ratios more similar to an island arc volcanic than a mid-ocean ridge volcanic. …


Spatiotemporal Evolution Of Pleistocene And Late Oligocene-Early Miocene Deformation In The Mecca Hills, Southernmost San Andreas Fault Zone, Amy C. Moser 2017 Utah State University

Spatiotemporal Evolution Of Pleistocene And Late Oligocene-Early Miocene Deformation In The Mecca Hills, Southernmost San Andreas Fault Zone, Amy C. Moser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Seismogenically active faults (those that produce earthquakes) are very complex systems that constantly change through time. When an earthquake occurs, the rocks surrounding a fault (the “fault rocks”) become altered or damaged. Studying these fault rocks directly can inform what processes operated in the fault and how the fault evolved in space and time. Examining these key aspects of faults helps us understand the earthquake hazards of active fault systems.

The Mecca Hills, southern California, consist of a set of hills adjacent to the southernmost San Andreas Fault. The topography is related to motion on the San Andreas fault, which …


Late Cretaceous Extensional Collapse Of The Southern Cordillera: Evidence From The Bristol And Granite Mountains, Se California, Lee Hess 2017 University of Nevada, Las Vegas

Late Cretaceous Extensional Collapse Of The Southern Cordillera: Evidence From The Bristol And Granite Mountains, Se California, Lee Hess

UNLV Theses, Dissertations, Professional Papers, and Capstones

Demonstrating the regional extent of Late Cretaceous extensional collapse of western North America’s southern Cordillera is important to understanding the tectonic evolution of the Sevier-Laramide orogens, and the geodynamics of ancient and modern orogens and synconvergent extension. Documenting Late Cretaceous extension in the southern Cordillera requires looking through the extensive overprint by Cenozoic structures. Late Cretaceous extension in the eastern Mojave region has been inferred from geochronology and thermochronology studies, which document Late Cretaceous cooling of Mesozoic granitoid rocks, some of which were emplaced in the middle crust. Cooling histories from these rocks have also been interpreted to be a …


Investigating Patterns Of Fluvial Form And Incision Near The Yellowstone Hotspot — Alpine Canyon Of The Snake River, Wyoming, Daphnee Tuzlak 2017 Utah State University

Investigating Patterns Of Fluvial Form And Incision Near The Yellowstone Hotspot — Alpine Canyon Of The Snake River, Wyoming, Daphnee Tuzlak

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The shape of a landscape is created by rivers, which erode the underlying bedrock and carve through mountains. The Snake River flows across the uplifting hotspot plume of the Yellowstone region, cuts through the Snake River Range, and ultimately enters the low-lying eastern Snake River Plain. Although there is a good understanding of the track of the Yellowstone hotspot over geologic time and shorter timescales, measurements over Quaternary timescales and an understanding of how uplift influences the rivers and landscape in the Yellowstone region are absent. We study the Snake River and its past deposits where it cuts through Alpine …


Sequence Stratigraphy, Chemostratigraphy, And Biostratigraphy Of Lower Ordovician Units In Northeastern And Western Central Utah: Regional Implications, Colter R. Davis 2017 Utah State University

Sequence Stratigraphy, Chemostratigraphy, And Biostratigraphy Of Lower Ordovician Units In Northeastern And Western Central Utah: Regional Implications, Colter R. Davis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Lower to Middle Ordovician Garden City Formation and Pogonip Group are mixed carbonate and sandy marine rocks deposited on the western margin of ancestral North America. The Garden City Formation was deposited in the Northern Utah Basin and the Pogonip Group was deposited in the Ibex Basin. These two basins experienced different rates of subsidence that resulting in significant thickness differences between rock units and different rock types related to sea level change. This study provides a unique opportunity to examine changes in rock types, rock chemistry, and fossil types as sea level changed within two separate basins in …


Using Cross-Sets For Paleodischarge Estimation And Paleocurrent Vectors In The Parthenon Sandstone, Northwest Arkansas, Sean Robert Parry 2017 University of Arkansas, Fayetteville

Using Cross-Sets For Paleodischarge Estimation And Paleocurrent Vectors In The Parthenon Sandstone, Northwest Arkansas, Sean Robert Parry

Graduate Theses and Dissertations

In this thesis, set thicknesses are used to estimate the paleohydraulics (paleodischarge and give magnitudes for paleocurrent directions) of the ancient river system which deposited the Parthenon Sandstone in northwest Arkansas. Set thickness is the vertical thickness of a group of strata conformable series (Mckee and Weir, 1953); set thickness represents truncated dunes. The goal of this thesis is to: 1) obtain paleodischarge estimates of the Parthenon sandstone via cross-sets and compare the results with previously calculated discharge estimates which use basin area to discharge collation techniques and 2) use paleodischarge estimates calculated within this thesis to give magnitude to …


Sensitivity Of Mangrove Range Limits To Climate Variability, Kyle C. Cavanaugh, Michael J. Osland, Remi Bardou, Gustavo Hinojosa-Arango, Juan M. Lopez-Vivas, John D. Parker, Andre S. Rovai 2017 Department of Geography, University of California

Sensitivity Of Mangrove Range Limits To Climate Variability, Kyle C. Cavanaugh, Michael J. Osland, Remi Bardou, Gustavo Hinojosa-Arango, Juan M. Lopez-Vivas, John D. Parker, Andre S. Rovai

United States Geological Survey: Staff Publications

Aim: Correlative distribution models have been used to identify potential climatic controls of mangrove range limits, but there is still uncertainty about the relative importance of these factors across different regions. To provide insights into the strength of climatic control of different mangrove range limits, we tested whether temporal variability in mangrove abundance increases near range limits and whether this variability is correlated with climatic factors thought to control large scale mangrove distributions.

Location: North and South America.

Time period: 1984–2011.

Major taxa studied: Avicennia germinans, Avicennia schuaeriana, Rhizophora mangle, Laguncularia racemosa.

Methods: We characterized temporal variability in the enhanced …


Creating A Scaling Relationship Between Peak Discharge And Drainage Area To Identify Tile Drainage Inputs Into An Agricultural Stream, Ryan Plath 2017 Illinois State University

Creating A Scaling Relationship Between Peak Discharge And Drainage Area To Identify Tile Drainage Inputs Into An Agricultural Stream, Ryan Plath

Theses and Dissertations

Tile drains have been shown to contribute to high levels of nitrate in agricultural streams. Locations of tile drains on a watershed scale, however, are often unknown due to tile drains being located on many separate parcels of private property. This study evaluates the ability of a methodology, using scaling relationships between discharge and drainage area, for locating areas of large tile drainage contribution to Money Creek, in McLean County, Illinois. Additionally, this study examines the difference in scaling relationships and physical stream hydrology between tileflow and no-tileflow conditions. Eight stream sites were created in the watershed, that recorded stage …


Slope, Grain Size, And Roughness Controls On Dry Sediment Transport And Storage On Steep Hillslopes, Roman A. DiBiase, Michael P. Lamb, Vamsi Ganti, Adam M. Booth 2017 Pennsylvania State University

Slope, Grain Size, And Roughness Controls On Dry Sediment Transport And Storage On Steep Hillslopes, Roman A. Dibiase, Michael P. Lamb, Vamsi Ganti, Adam M. Booth

Geology Faculty Publications and Presentations

Existing hillslope sediment transport models developed for low-relief, soil-mantled landscapes are poorly suited to explain the coupling between steep rocky hillslopes and headwater channels. Here we address this knowledge gap using a series of field and numerical experiments to inform a particle-based model of sediment transport by dry ravel—a mechanism of granular transport characteristic of steep hillslopes. We find that particle travel distance increases as a function of the ratio of particle diameter to fine-scale (1m) topographic variability associated with rocky landscapes. Applying a 2-D dry-ravel-routing model to lidar-derived surface topography, we show how spatial patterns of local and nonlocal …


Vegetation Habitat Mapping Of Mammoth Cave National Park Using Multi-Date Landsat-8 Imagery And Lidar Data, Hongli Yang 2017 Murray State University

Vegetation Habitat Mapping Of Mammoth Cave National Park Using Multi-Date Landsat-8 Imagery And Lidar Data, Hongli Yang

Steeplechase: An ORCA Student Journal

Vegetation habitat mapping can be regarded as a model predicting the geographic distribution of plant cover types from mapped environmental variables. This paper discusses three environmental factors- slope, aspect and bedrock geology that determined different habitat types in Mammoth Cave National Park. The variation of aspect and slope can largely determine the amount of solar radiation and water available to vegetation, which influences the contrasting habitat types formed in a long term. Bedrock geology, one of the most influential factor in the study area, primarily controls the soil types and drainage conditions that support the various habitat types. The habitat …


Karst Sub-Basin Delineation Via Dye Trace Study Near Turnhole Bend, Mammoth Cave National Park, Jake Tholen 2017 Western Michigan University

Karst Sub-Basin Delineation Via Dye Trace Study Near Turnhole Bend, Mammoth Cave National Park, Jake Tholen

Honors Theses

Establishing watershed boundaries is a critical stage in understanding the local water cycle. Drainage basins are typically identified by topographic divides; water flows to successively lower locations along the most direct path available. The karst terrain in Mammoth Cave National Park, however, presents additional challenges in identifying the boundaries of these basins. Underground drainages in the form of caves or conduits often do not correspond with surface topography. These passages can redirect water far from the most immediate surface release.

A dye trace study is designed to identify flow paths from the surface to springs along the Green River. Three …


Classifying Microseismicty At Mount St. Helens Using A Large-N Array, Margaret E. Glasgow 2017 University of new mexico

Classifying Microseismicty At Mount St. Helens Using A Large-N Array, Margaret E. Glasgow

Earth and Planetary Sciences ETDs

A dense array of ~1,000 continuously recording, short-period geophones was deployed in the summer of 2014 within ~15 km of Mount St. Helens. Two earthquake catalogs created using reverse time imaging and template detection techniques, increase the detection rate and completeness of the earthquake catalog when compared to the permanent network, Pacific Northwest Seismic Network, catalog. An investigation into event type for ~200 of the earthquake detections leads to the discrimination of two major classification groups, volcano-tectonic and long period. Previous to this study, long period earthquakes had not been identified in the upper crust during a volcanically inactive period …


Fixation And Redistribution Of Arsenic During Early And Late Diagenesis In The Organic Matter-Rich Members Of The Lockatong Formation, Newark Basin, Usa: Implications For The Quality Of Groundwater, Larbi Rddad 2017 CUNY Kingsborough Community College

Fixation And Redistribution Of Arsenic During Early And Late Diagenesis In The Organic Matter-Rich Members Of The Lockatong Formation, Newark Basin, Usa: Implications For The Quality Of Groundwater, Larbi Rddad

Publications and Research

The Byram and Walls Island members in the lower and upper sections, respectively, of the Lockatong Formation in the Newark basin near the border between Pennsylvania and New Jersey were chosen to assess (i) the role of euxinic/anoxic conditions in sequestering arsenic (As) and other trace elements and (ii) the redistribution of these elements during catagenetic transformations. These members are rich in organic matter and host pyrite which occurs as disseminations, small patches, and subparallel veins. e sulfur isotope values of pyrite samples range between -7.5 and 0.5 ‰CDT (average = -3.5‰CDT). e negative δ34S values are indicative of Bacterial …


Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan 2017 School of Resources and Environment Science, East China Normal University, Shanghai, China

Investigations Of The Spatial And Temporal Variations Of Sr And Nd Isotopes In Sediments From Two Indian Rivers: Implications To Source Identification, Sonali Pradhan, Jing Zhang, Mark Baskaran, Prabhaker Vasant Shirodkar, Ying Wu, Umesh Kumar Pradhan

Environmental Science and Geology Faculty Research Publications

Radiogenic isotopes of Sr and Nd provide crucial information on chemical and physical erosion processes, therefore used as tracers for fingerprinting the sources of fluvial sediments. Moreover, elemental geochemistry, 87Sr/86Sr and 143Nd/144Nd signatures in silicate fractions of sediments primarily reflect intricate controls of characteristics and provenance of sediment. A suite of sediment samples collected from two rivers of India, Narmada (large) and Netravati (small) were analyzed for elemental concentrations, 87Sr/86Sr and 143Nd/144Nd in silicate as well as acid-leachable fractions. 87Sr/86Sr in acid-leachable sediment fractions from both the rivers (0.7094 ± 0.0002 for Narmada and 0.7158 ± 0.003 for Netravati) showed …


Δ13c And Δ15n In The Endangered Kemp’S Ridley Sea Turtle Lepidochelys Kempii After The Deepwater Horizon Oil Spill, Kimberly J. Reich, Melania C. López-Castro, Donna J. Shaver, Claire Iseton, Kristen M. Hart, Michael J. Hooper, Christopher J. Schmitt 2017 Texas A&M University at Galveston & Palm Beach Atlantic University

Δ13c And Δ15n In The Endangered Kemp’S Ridley Sea Turtle Lepidochelys Kempii After The Deepwater Horizon Oil Spill, Kimberly J. Reich, Melania C. López-Castro, Donna J. Shaver, Claire Iseton, Kristen M. Hart, Michael J. Hooper, Christopher J. Schmitt

United States Geological Survey: Staff Publications

The Deepwater Horizon explosion in April 2010 and subsequent oil spill released 3.19 × 106 barrels (5.07 × 108 l) of MC252 crude oil into important foraging areas of the endangered Kemp’s ridley sea turtle Lepidochelys kempii (Lk) in the northern Gulf of Mexico (GoM). We measured δ13C and δ15N in scute biopsy samples from 33 Lk nesting in Texas during the period 2010 to 2012. Of these, 27 were equipped with satellite transmitters and were tracked to traditional foraging areas in the northern GoM after the spill. Differences in δ13C between the oldest and newest scute layers from 2010 …


Vegetation Response To Invasive Tamarix Control In Southwestern U.S. Rivers: A Collaborative Study Including 416 Sites, Eduardo Gonzalez, Anna A. Sher, Robert M. Anderson, Robin F. Bay, Daniel W. Bean, Gabriel J. Bissonnete, Berenger Bourgeois, David J. Cooper, Kara Dohrenwend, Kim D. Eichhorst, Hishma El Waer, Deborah K. Kennard, Rebecca Harms-Weissinger, Annie L. Henry, Lori J. Makarick, Steven M. Ostoja, Lindsay V. Reynolds, W. Wright Robinson, Patrick B. Shafroth 2017 Universite de Toulouse & University of Denver

Vegetation Response To Invasive Tamarix Control In Southwestern U.S. Rivers: A Collaborative Study Including 416 Sites, Eduardo Gonzalez, Anna A. Sher, Robert M. Anderson, Robin F. Bay, Daniel W. Bean, Gabriel J. Bissonnete, Berenger Bourgeois, David J. Cooper, Kara Dohrenwend, Kim D. Eichhorst, Hishma El Waer, Deborah K. Kennard, Rebecca Harms-Weissinger, Annie L. Henry, Lori J. Makarick, Steven M. Ostoja, Lindsay V. Reynolds, W. Wright Robinson, Patrick B. Shafroth

United States Geological Survey: Staff Publications

Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced …


Digital Commons powered by bepress