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Articles 271 - 300 of 975

Full-Text Articles in Physical Sciences and Mathematics

Fracture Analysis Of The Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge, Trent Jackson Dec 2019

Fracture Analysis Of The Lower Oceanic Crust, Atlantis Bank, Southwest Indian Ridge, Trent Jackson

Master's Theses

Atlantis Bank (AB) is an oceanic core complex (OCC), formed at the slow-spreading (spreading rate/yr) Southwest Indian Ridge (SWIR)-Atlantis II transform junction. AB is a domal massif composed of lower crustal and upper mantle rocks exhumed along a normal-sense detachment shear zone/fault. OCCs are of high interest since oceanic crust comprises the majority of Earth’s crust and OCCs form up to 15% of the crust that is formed at slow-spreading ridges. Brittle deformation, such as faults and fractures provide pathways for fluids to interact with the crust, which increases heat and mass exchange between the crust and hydrosphere, and is …


The Role Of Introductory Geoscience Courses In Preparing Teachers—And All Students—For The Future: Are We Making The Grade?, Anne E. Egger Oct 2019

The Role Of Introductory Geoscience Courses In Preparing Teachers—And All Students—For The Future: Are We Making The Grade?, Anne E. Egger

Geological Sciences Faculty Scholarship

Introductory geoscience courses enroll hundreds of thousands of students a year, most of whom do not major in the geosciences. For many, including future K–12 teachers, an introductory course is the only place they will encounter Earth science at the college level. New standards for K–12 science education have profound implications for teacher preparation, particularly in Earth science. The new standards call for taking a systems approach, highlighting how humans interact with Earth, making use of science and engineering practices, and engaging students in discourse. Analysis of responses to the National Geoscience Faculty Survey (n = 813 in 2004; …


The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon Aug 2019

The Spatial And Temporal Evolution Of The Portland And Tualatin Basins, Oregon, Usa, Darby Patrick Scanlon

Dissertations and Theses

The Portland and Tualatin basins are part of the Puget-Willamette Lowland in the Cascadia forearc of Oregon and Washington. The Coast Range to the west has undergone Paleogene transtension and Neogene transpression, which is reflected in basin stratigraphy. To better understand the tectonic evolution of the region, I modeled three key stratigraphic horizons and their associated depocenters (areas of maximum sediment accumulation) through space and time using well log, seismic, outcrop, aeromagnetic, and gravity data. Three isochore maps were created to constrain the location of Portland and Tualatin basin depocenters during 1) Pleistocene to mid-Miocene (0-15 Ma), 2) eruption of …


An Overview Of Handheld Sun Photometer Measurements Of Atmospheric Aerosols In New Orleans, Louisiana: A Case Study Of The Xavier University Study Site., M. Bradley, B. Sevalia, M. Gasseller Jul 2019

An Overview Of Handheld Sun Photometer Measurements Of Atmospheric Aerosols In New Orleans, Louisiana: A Case Study Of The Xavier University Study Site., M. Bradley, B. Sevalia, M. Gasseller

Faculty and Staff Publications

Aerosol optical depth (AOT) was measured at Xavier University of Louisiana (XULA, 29.96ᵒ N, 90.11° W and 3m above sea level) using a GLOBE handheld sun photometer. The measurements were done at two different wavelengths, 505nm and 625nm. The measured values were used to extrapolate the AOT values for wavelengths 667nm, 551nm, 532nm and 490nm at the XULA site. The measured and calculated AOT values were then compared with values from the nearest AERONET station at Wave CIS site 6 (AERONET, 28.87ᵒ N, 90.48° W and 33m above sea level), which is 60 miles south of XULA. In this study …


Effects Of Heat Treatment Of Spinels As Determined By Vis/Nir And Raman Spectroscopy And Xrd, Jill Reale, Dr. Michael B. Wolf Jun 2019

Effects Of Heat Treatment Of Spinels As Determined By Vis/Nir And Raman Spectroscopy And Xrd, Jill Reale, Dr. Michael B. Wolf

Celebration of Learning

Heat treatment is done to improve the color and clarity and, therefore, the value of gemstones. The objectives of this study include observing color and inclusion changes in pink spinels after heat treatment, and analyzing structural changes within differently colored spinels using Raman Spectroscopy and X-ray diffraction with a Paris Edinburgh Press. We expected the heat treatment to yield color changes and fading of small inclusions. Cut and polished spinels were heated to 1400C for 2 days or 850C for 3 days. Future experiments involve 800C, 750C, and 700C all for 1 week, 1500C for 4 days, and 1600C for …


Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson Jun 2019

Investigation Of Pervasive Clay Layers And Their Effect On Groundwater Flow Using Electrical Resistivity Tomography In The San Antonio Groundwater Basin, James M. Carlson

Natural Resources Management and Environmental Sciences

The United States Geological Survey is developing an integrated hydrologic model of the San Antonio Creek Groundwater Basin to better understand and simulate the integrated surface water and groundwater system. An abrupt 60 meter offset in groundwater depth over a distance of less than one kilometer is observed in well readings within the Cañada De Las Flores region of the groundwater basin. Abrupt changes in groundwater levels are often explained by the presence of a fault in the subsurface vertically offsetting sedimentary units. However, observations of the structural geology of this region indicates that faulting is unlikely and suggests an …


Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge May 2019

Genetic Sequencing For Measuring Biodiversity In Recent And Ancient Marine Sediments, Lauren Judge

Celebration of Learning

Taxonomic biodiversity, measured by counting the number of species present in a given area, is the most common method of capturing ecosystem biodiversity in recent and ancient environments. While this method is widely accepted, it is limited by poor preservation and identification of many individuals, making it impossible to include every species within an ecosystem and resulting in the loss of some diversity information. To address this issue, we measured the genetic biodiversity (in which species are determined based on sequencing of their DNA) of shallow marine ecosystems by extracting and sequencing the 18S ribosomal gene from bulk carbonate sediment …


Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig May 2019

Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig

Celebration of Learning

The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …


Grain Size And Vegetation As Controlling Variables Of Stream Channel Morphology, Grant Colip May 2019

Grain Size And Vegetation As Controlling Variables Of Stream Channel Morphology, Grant Colip

Senior Honors Projects, 2010-2019

Streams are one of the major driving forces that shape the landscapes in the Shenandoah Valley of Virginia and the eastern United States as a whole, and they serve an important role in transporting both water and sediment to the Atlantic Ocean. However, streams are often modified for human use, thus altering their natural equilibrium. These alterations have frequently led to the degradation of channel stability as well as damage to property and infrastructure. A better understanding of how both grain size (D50) and vegetation impact stream sinuosity (S) is needed to analyze the prevalence of channel degradation …


Multi-Proxy Characterization Of Acex Subunit 1/5 (The “Zebra” Interval) To Better Understand Sediment Deposition At This Critical Age Boundary And Paleoceanographic Transition, Victoria Hojnacki May 2019

Multi-Proxy Characterization Of Acex Subunit 1/5 (The “Zebra” Interval) To Better Understand Sediment Deposition At This Critical Age Boundary And Paleoceanographic Transition, Victoria Hojnacki

Senior Honors Projects, 2010-2019

Sediment cores recovered from the Lomonosov Ridge on IODP Expedition 302, the Arctic Coring Expedition (ACEX), provided the first major insights into long-term Cenozoic history of climate and ocean conditions in the central Arctic. However, the ACEX record is hampered by a major hiatus or severely condensed interval (depending on age-model interpretations) at 198.7 mcd separating the middle Eocene and Miocene records. Lithologic subunit 1/5 lies above this depth horizon, and is informally called the “zebra interval” because of distinctive stripes - black and gray tilted and cross-banded silty-clay layers, up to 3 cm thick that characterize the lower ~2.5 …


Feature Identification In Time Series Data Sets, Justin Shaw, Marek Stastna, Aaron Coutino, Ryan K. Walter, Eduard Reinhardt May 2019

Feature Identification In Time Series Data Sets, Justin Shaw, Marek Stastna, Aaron Coutino, Ryan K. Walter, Eduard Reinhardt

Physics

We present a computationally inexpensive, flexible feature identification method which uses a comparison of time series to identify a rank-ordered set of features in geophysically-sourced data sets. Many physical phenomena perturb multiple physical variables nearly simultaneously, and so features are identified as time periods in which there are local maxima of absolute deviation in all time series. Unlike other available methods, this method allows the analyst to tune the method using their knowledge of the physical context. The method is applied to a data set from a moored array of instruments deployed in the coastal environment of Monterey Bay, California, …


Fun In A Kansas Salt Mine, Robert F. Diffendal Jr. Apr 2019

Fun In A Kansas Salt Mine, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Most people probably do not know that salt deposits hundreds of feet thick lie buried beneath large parts of western Kansas, western Oklahoma and a small part of the northeastern Texas Panhandle. Native Americans and early European explorers found that where the salt deposits came near the land surface (for, example north of Hutchinson, Kansas) salt is dissolved by ground water and increases the salinity of rivers, streams, springs and ponds. This salty water was used as a salt source by these peoples. The Hutchinson Salt, a 275 million-year-old Middle Permian deposit, was discovered in an exploratory drill hole in …


Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson Apr 2019

Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson

Masters Theses

The Silurian Niagaran Pinnacle Reefs of the Michigan Basin retain their relevance after primary recovery of hydrocarbons and are excellent candidates for carbon dioxide sequestration, natural gas storage, and enhanced oil recovery. Due to the nature of carbonate rocks, these reef complexes are heterogeneous and lateral interpolation between observations in wells, is ambiguous. Ambiguity has led to large uncertainty and disagreement regarding reef architectures and their internal facies distributions. Previous models of these reef complexes have relied almost entirely on well logs and conventional core. This study focused on integrating 3D seismic reflection data to reduce uncertainty when delineating the …


The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory Mar 2019

The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory

LSU Doctoral Dissertations

Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. …


Investigations Of The Potential For Irrigated Agriculture On The Bonaparte Plains: Bore Completion Report, 2nd Edition, D L. Bennett Feb 2019

Investigations Of The Potential For Irrigated Agriculture On The Bonaparte Plains: Bore Completion Report, 2nd Edition, D L. Bennett

Resource management technical reports

Drilling programs were undertaken in 2013 and 2016 by the former Department of Agriculture and Food, Western Australia and in 2017 by DPIRD, at 10 sites in the Bonaparte Plains area, north of Kununurra in the East Kimberley region of Western Australia (WA).

These drilling programs were a component of resource availability and risk investigations conducted to determine the potential for developing irrigated agriculture on 30 000 hectares of Cockatoo Sands — free-draining loamy soils that have the potential to support crops in the wet and dry seasons. There was limited hydrogeological information available at a suitable scale for the …


1901 - Soil Survey Of The Lower Salinas Valley California, Macy H. Lapham And W. H. Heileman Jan 2019

1901 - Soil Survey Of The Lower Salinas Valley California, Macy H. Lapham And W. H. Heileman

Miscellaneous Monterey and San Luis Obispo County Documents and Reports

Prepared by the U.S. Department of Agriculture, Bureau of Soils, this report addresses the conditions found in the Lower Salinas Valley of Monterey County, California in 1901, including the development of agriculture, climate, geology, soil types, cultivation, irrigation. groundwater, and alkali found in the soil.


1901 - Soil Survey Of The Lower Salinas Valley California, Macy H. Lapham And W. H. Heileman Jan 2019

1901 - Soil Survey Of The Lower Salinas Valley California, Macy H. Lapham And W. H. Heileman

Miscellaneous Documents and Reports

Prepared by the U.S. Department of Agriculture, Bureau of Soils, this report addresses the conditions found in the Lower Salinas Valley of Monterey County, California in 1901, including the development of agriculture, climate, geology, soil types, cultivation, irrigation. groundwater, and alkali found in the soil.


1921 - Petroleum Resources Of California, Bulletin 89 Jan 2019

1921 - Petroleum Resources Of California, Bulletin 89

Miscellaneous Documents and Reports

By 1921, the increasing demand for petroleum and its products, and the inability of production to keep pace with requirements, for several years, resulted in widespread prospecting throughout the world for possible new oil fields. In California, "wild-cat" wells were being drilled in many localities, some of them in places where even a cursory inspection of the geology would tell the futility of looking for oil. This report aimed to furnish information as to the unfavorable as well as the favorable areas of development of additional petroleum resources in California. The purpose of the report was to briefly take stock …


1923 - Flow In California Streams, Bulletin No. 5, Appendix A, Report To The Legislature Jan 2019

1923 - Flow In California Streams, Bulletin No. 5, Appendix A, Report To The Legislature

Miscellaneous Documents and Reports

The legislature of 1921 appropriated $200,000 for an investigation of California's water resources by the State Department of Public Works, Division of Engineering and Irrigation. Accordingly, an engineering investigation was completed and a report on California's water resources transmitted to the legislature on January 1, 1923. The report addresses the geology, precipitation and run-off in California.


1997 - Water Resources Data Report, Water Year 1994-1995 Jan 2019

1997 - Water Resources Data Report, Water Year 1994-1995

Monterey County Water Resources Agency Water Reports

California State legislation outlines the objectives and purposes of the Monterey County Water Resources Agency (MCWRA) and states that the MCWRA is to “carry on technical and other necessary investigations, make measurements, collect data, make analyses, studies and inspections pertaining to water supply, water rights, control of flood and storm waters and use of water both within and outside of the agency ...” The MCWRA is responsible for the managing, planning and engineering of the water resources of the Salinas Valley. This report was prepared in part to fulfill that responsibility.


Paradoxical Behavior In Groundwater Levels In Response To Precipitation Events, Alexandra Shelters Jan 2019

Paradoxical Behavior In Groundwater Levels In Response To Precipitation Events, Alexandra Shelters

Browse all Theses and Dissertations

Groundwater levels are expected to fluctuate with precipitation, rising when precipitation increases and falling when it decreases. However, observations often show that groundwater levels rise in months when precipitation has decreased from the previous month, or alternately, falls in months when precipitation has increased from the previous month. Such paradoxical behavior is documented in a 30-year record for a monitoring well in southwestern Ohio. This record was analyzed to evaluate the hypothesis that mass balance controls the change in groundwater level such that changes cannot be predicted solely from monthly changes in precipitation. Though precipitation may vary from one month …


Investigating An Apparent Structural High In Seismic Data In North Terre Haute, Indiana, Through First-Arrival Traveltime Tomography And Gravity Analysis, Daniel Grant Koehl Jan 2019

Investigating An Apparent Structural High In Seismic Data In North Terre Haute, Indiana, Through First-Arrival Traveltime Tomography And Gravity Analysis, Daniel Grant Koehl

Browse all Theses and Dissertations

This study focuses on northern Terre Haute, Indiana, where seven 2D seismic reflection time sections were collected by CountryMark and donated to Wright State University. Geologically, the area is on the eastern margin of the Illinois Basin. Two of these seismic lines display significant relief along a continuous, high-amplitude horizon approximately 180 milliseconds in two-way traveltime depth. This horizon was previously interpreted by CountryMark to be a Silurian reef core of the type common in this region of the Illinois Basin; however, other seismic lines within the data set display no relief. Furthermore, borehole logs within the area show no …


An Analysis Of Fractures Around The Sevier Fault Zone Near Orderville, Utah, Charley H. Hankla Jan 2019

An Analysis Of Fractures Around The Sevier Fault Zone Near Orderville, Utah, Charley H. Hankla

Senior Independent Study Theses

Structural discontinuities—such as opening mode joints, shear fractures, and faults— tend to occur in close geographic proximity to one another; however, the timing relationships between these structures is not always easy to discern in the field. In southwestern Utah, the Jurassic Navajo Sandstone is cut by large-scale normal faults associated with the Sevier Fault Zone, making it perfect for observing several fracture types. The aim of this study is to complete a dynamic and kinematic analyses of the fractures near a major fault and to determine the chronologic relationships between the fractures. Specifically, we observed a previously unnamed segment of …


Biodiversity And Distribution Of Benthic Foraminifera In Harrington Sound, Bermuda: The Effects Of Physical And Geochemical Factors On Dominant Taxa, Nam Le Jan 2019

Biodiversity And Distribution Of Benthic Foraminifera In Harrington Sound, Bermuda: The Effects Of Physical And Geochemical Factors On Dominant Taxa, Nam Le

Honors Theses

Harrington Sound, Bermuda, is a nearly enclosed lagoon acting as a subtropical/tropical, carbonate-rich basin in which carbonate sediments, reef patches, and carbonate-producing organisms accumulate. Here, one of the most important calcareous groups is the Foraminifera. Analyses of common benthic orders, including miliolids (Quinqueloculina and Triloculina spp.) and rotaliids (Homotrema rubrum, Elphidium spp., and Ammonia beccarii), are essential in understanding past and present environmental conditions affecting the island's coastal environment. These taxa have been studied previously; however, factors explaining their individual patterns of abundance in the Sound are not well detailed. The goal of this study is …


Chondrichthyan Diversity Within The Burlington-Keokuk Fish Bed Of Southeast Iowa And Northwest Illinois (Mississippian: Osagean), Matthew Michael James Hoenig Jan 2019

Chondrichthyan Diversity Within The Burlington-Keokuk Fish Bed Of Southeast Iowa And Northwest Illinois (Mississippian: Osagean), Matthew Michael James Hoenig

Browse all Theses and Dissertations

Chondrichthyan remains occur in abundance within a thin layer of limestone at the top of the Burlington Limestone at the point of the contact with the overlying Keokuk Limestone. This layer of rock, the "Burlington-Keokuk Fish Bed," is stratigraphically consistent and laterally extensive in exposures of the Burlington Limestone near its type section along the Iowa-Illinois border. Deposition of the fish bed occurred on the Burlington Continental Shelf carbonate ramp off the subtropical western coast of Laurussia during the Lower Carboniferous (Late Tournaisian; Osagean) due to a drop in sea level, although the specific mechanism(s) that concentrated the vertebrate fossils …


Interpreting Vegetation And Soil Anomalies In The Guarumen Area Of Northwestern Venezuela Using Remote Sensing Applications, Tyler Edward Ricketts Jan 2019

Interpreting Vegetation And Soil Anomalies In The Guarumen Area Of Northwestern Venezuela Using Remote Sensing Applications, Tyler Edward Ricketts

Electronic Theses and Dissertations

The Guarumen area of Venezuela is a tectonically active region that is approximately 1,640 mi2 across the northern portions of the Barinas Basin and the foothills of the Mérida Andes. It is structurally influenced by the Caribbean plate to the north, the Nazca plate to the west, and the Maracaibo block against the Guyana Shield of the South American Plate. These result in an oblique boundary that gives rise to the fold-and-thrust belt of the Mérida Andes to the west, and the Caribbean Mountain system to the north, in concordance to the right-lateral shearing that is evidenced by the Boconó …


Geology Of Southeastern Nebraska, Robert Matthew Joeckel, Dana Divine, Leslie M. Howard, Kathleen Cameron, Michele M. Waszgis Jan 2019

Geology Of Southeastern Nebraska, Robert Matthew Joeckel, Dana Divine, Leslie M. Howard, Kathleen Cameron, Michele M. Waszgis

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Exploration For Alteration Halos Around The Ag-W Deposits In Southeastern Missouri, Usa, Daniel Joseph Warbritton Jan 2019

Exploration For Alteration Halos Around The Ag-W Deposits In Southeastern Missouri, Usa, Daniel Joseph Warbritton

Masters Theses

"The St. Francois Mountains in SE Missouri are an extensive terrane of granitic ring complexes and associated rhyolites. They were an important source of Ag, W, and Sn and mined intermittently from the 1800s until the 1950s. The Ag-W ores occur in the Silvermine Granite and rhyolite roof rocks. The deposits are classified as a xenothermal ore system with mineralization occurring in quartz veins and surrounding greisen (up to 2.5 m). Exploration for hydrothermal ore deposits often focuses on the identification of alteration halos in the surrounding host rocks. In the vast majority of xenothermal ore deposits, such as in …


The Medicine Hat Block And The Assembly Of Laurentia: New Interpretations From Single-Grain Zircon Analyses, Blake Oswell Ladouceur Jan 2019

The Medicine Hat Block And The Assembly Of Laurentia: New Interpretations From Single-Grain Zircon Analyses, Blake Oswell Ladouceur

Electronic Theses and Dissertations

The Medicine Hat Block (MHB) is one of the core cratonic elements that amalgamated in the Paleoproterozoic to form Laurentia. However the role of the MHB in the formation of Laurentia is poorly constrained due to virtually all of the MHB being concealed by Proterozoic and younger supracrustal sequences limiting availability of data. The primary sources of samples from the MHB are 1) xenoliths of variable metamorphic grade including gneisses amphibolites and meta-plutonic rocks collected from Eocene volcanic rock; and 2) similar lithologies recovered from boreholes that penetrate to the MHB basement. Previous work on samples from the MHB yielded …


Late Devonian Sedimentary Record Of Appalachian Tectonics And Erosion: Geochronology And Geochemistry Of Detrital Muscovite And Zircon From Central Pennsylvania Strata, Cole T. Gardner Jan 2019

Late Devonian Sedimentary Record Of Appalachian Tectonics And Erosion: Geochronology And Geochemistry Of Detrital Muscovite And Zircon From Central Pennsylvania Strata, Cole T. Gardner

Honors Theses

Foreland basin sediment deposition in North-Central Pennsylvania during Late Devonian time records erosion of hinterland source terranes exhumed during regional plate convergence, including the collisional Acadian orogeny. The Catskill clastic wedge preserves a coarsening-upwards stratigraphic succession from marine to fluvial environments associated with sediment progradation and sea-level regression, yet depositional timescales and quantitative provenance data are largely unconstrained.

Detailed facies analysis of eight outcrops spanning >2 km of stratigraphy in Lycoming Co., Pennsylvania documents distinct upsection changes, interpreted to reflect changes in depositional environments consistent with previous sedimentology of the Catskill clastic wedge. Stratigraphy displays a transition from nearshore marine …