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

Geology Commons™

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

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1741 - 1770 of 29939

Full-Text Articles in Geology

251, Scott Brande Jan 2024

251, Scott Brande

All 3D Rock Models

Model 251 - anthracite - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/251-344dd33d2e8242e0a4717a571ec59b18


252, Scott Brande Jan 2024

252, Scott Brande

All 3D Rock Models

Model 252 - anthracite - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/252-434ee1d596184ec29197f0920570d5bb


254, Scott Brande Jan 2024

254, Scott Brande

All 3D Rock Models

Model 254 - hornfels - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/254-14a1101e965640a6b5c3f5149a8708e1


261, Scott Brande Jan 2024

261, Scott Brande

All 3D Rock Models

Model 261 - conglomerate - sedimentary rock

SketchFab link: https://sketchfab.com/3d-models/261-ec9156ee607242a7b4a9504d7c3af499


264, Scott Brande Jan 2024

264, Scott Brande

All 3D Rock Models

Model 264 - quartzite - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/264-946bceab652f4f4a9ce4a1bb6c4da9c0


270, Scott Brande Jan 2024

270, Scott Brande

All 3D Rock Models

Model 270 - slate - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/270-815ee7884c6b4a18ad11bdd18d0b14bf


267, Scott Brande Jan 2024

267, Scott Brande

All 3D Rock Models

Model 267 - marble - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/267-5cd2ad41b91248f5926fcc7a3848fba8


266, Scott Brande Jan 2024

266, Scott Brande

All 3D Rock Models

Model 266 - hornfels - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/266-b23a020c463f4f69ac3dd1ae659a2050


268, Scott Brande Jan 2024

268, Scott Brande

All 3D Rock Models

Model 268 - phyllite - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/268-ba9597eb3c504ed5b91fe6ab00e24418


Recent Paleolimnological History Of Jackson Lake, Grand Teton National Park, Wyoming (Usa), Hillary Johnson Jan 2024

Recent Paleolimnological History Of Jackson Lake, Grand Teton National Park, Wyoming (Usa), Hillary Johnson

Theses and Dissertations--Earth and Environmental Sciences

This study utilizes a recently acquired, high-resolution CHIRP seismic reflection dataset and a deepwater sediment core to analyze the recent stratigraphy of Jackson Lake (Wyoming, USA). The western shoreline of Jackson Lake is situated adjacent to the Teton fault, a down-to-the-east normal fault that produces the spectacular high topography of Grand Teton National Park. The sediments of Jackson Lake are underexplored and consequently, their value as indicators of hydroclimatic and tectonic changes is unknown. Here, the sedimentary fill of Jackson Lake is explored as a natural archive of environmental change, specifically in reference to the influence of human outlet engineering …


Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis Jan 2024

Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis

Theses and Dissertations--Earth and Environmental Sciences

Iron meteorites remain the only material view into planetary cores. Despite their scientific relevance, iron meteorites are relatively rare. In June 2021 and March 2022, the Kentucky Geological Survey received requests to identify two metallic specimens discovered in central Kentucky. The specimens were given the provisional names Handys Bend (3175.2 g) and Flax Creek (286.2 g). The goal of this project is to confirm meteoritic origin, characterize their structures and chemistry, assign genetic classifications, and examine potential relations to previous discoveries. Petrography was conducted using scanning electron microscopy. Mineral phases were examined using X-Ray diffraction crystallography. Chemical compositions were determined …


Thermal Alteration Of The Mineralogy Of Calcium Sulfoaluminate Cements: Implications For The Performance Of Rapid Repair Materials, Jillian Cavellier Jan 2024

Thermal Alteration Of The Mineralogy Of Calcium Sulfoaluminate Cements: Implications For The Performance Of Rapid Repair Materials, Jillian Cavellier

Theses and Dissertations--Earth and Environmental Sciences

Calcium sulfoaluminate (CSA) was developed in part to lessen the environmental impact of cementitious materials compared to traditional Portland cements. CSA was first put into production in the 1970s and has been undergoing various performance testing to investigate its durability. Yet to be evaluated is CSA’s response to a rapid, high temperature event. In this study, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometry and scanning electron microscope imaging were used to analyze alterations in the mineralogy due to such an event. As found in previous studies, after ~125°C, ettringite has been completely dehydrated. Ettringite decomposes into bassanite and calcium …


Assessing Microplastic Contamination Within Karst Groundwater Basins In Kentucky, Maaz Fareedi Jan 2024

Assessing Microplastic Contamination Within Karst Groundwater Basins In Kentucky, Maaz Fareedi

Theses and Dissertations--Earth and Environmental Sciences

The input and abrasion of plastic waste in the environment has long been known to form microplastics (MPs). These ubiquitous contaminants are easily mobilized into hydrologic systems. MPs are now being found in karst aquifers around the world, including several across Kentucky, USA. Due to their size (< 5 mm in diameter), chemical properties, abundance, and wide distribution, MPs pose numerous ecological hazards, including uptake by organisms and as substrates for contaminant sorption. Karst groundwater is especially vulnerable to surface contaminants; however, knowledge of the extent of karst MP contamination is limited, with most studies focused on individual sites or small areas. In this study, we created a MP contamination dataset for 30 karst springs and 10 locations where cave sediments were characterized across Kentucky. MP concentrations in groundwater samples ranged from 0 to 41.1 items/L and yielded an average of 4.9 ± 8.7 items/L. Sediment MP concentrations ranged from 0 to 306 items/kg. We performed statistical analyses and linear regressions to examine whether groundwater MP concentrations could be explained by factors including land use, population density, basin area, numbers of sinkholes, and sinking streams. Our models revealed that population density, agrarian land use, sinking stream density, and basin area were related to MP concentrations. All factors except basin area trended positively with MP concentration, while basin area trended negatively. These relations are generally corroborated by existing literature, however they indicate that further studies with considerably larger sample sizes are needed to determine mechanistic relationships.


Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary Jan 2024

Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary

Theses and Dissertations--Earth and Environmental Sciences

Landslide hazards are a persistent threat to communities and infrastructure in Eastern Kentucky, where steep slopes, shallow colluvial soils, and variable hydrological conditions make slope failures frequent. This thesis presents an integrated approach to landslide hazard mapping (LHM) through the development of dynamic, spatiotemporal LHMs for shallow colluvial landslides. Two studies within this work investigate and refine the use of the Lu and Godt (2008) factor of safety (FS) equation to improve landslide predictions. The first study establishes a novel LHM workflow using Hydrus-1D to simulate soil moisture infiltration and fluctuations from precipitation and evapotranspiration (ET) data. This study also …


Alteration Of Ultramafic Lamprophyres And Its Effect On Rare Earth Element Distribution In The Illinois-Ketucky Fluorspar District, Zachary O. Walton Jan 2024

Alteration Of Ultramafic Lamprophyres And Its Effect On Rare Earth Element Distribution In The Illinois-Ketucky Fluorspar District, Zachary O. Walton

Theses and Dissertations--Earth and Environmental Sciences

The ultramafic lamprophyres of the Illinois-Kentucky Fluorspar District (IKFD) have been identified as a potential domestic source of rare earth elements (REEs). The present distribution of the REEs and the role of the carbonate alteration in the distribution of the REEs is poorly understood. Petrographic and geochemical analyses were employed to determine the nature of the mantle source region and timing of the carbonate mineralization. Ratios of 143Nd/144Nd vs. 87Sr/86Sr demonstrate that in addition to the intrusion of primitive magma into the crust, a melt was generated from a mantle source region metasomatized by …


Re-Examination Of A Middle Mississippian Carbonate Mud-Mound Complex From The Fort Payne Formation In South-Central, Kentucky, Maxwell Mickelson Jan 2024

Re-Examination Of A Middle Mississippian Carbonate Mud-Mound Complex From The Fort Payne Formation In South-Central, Kentucky, Maxwell Mickelson

Theses and Dissertations--Earth and Environmental Sciences

This study examines the origin of a 213-m (700-ft) long, Middle Mississippian, carbonate “mud-mound complex” in the Fort Payne Formation of south-central Kentucky. The complex’s well-exposed, easily accessible, and well-preserved nature provides an opportunity to understand how mounds like this developed during a time of sediment starvation, basinward of the largely abandoned Borden-Grainger Delta complex.

The mound complex is formed of small, accretionary mounds that accreted onto the flanks of an eroded structural high and onto the backs of each other, apparently for protection from storms. Each sub-mound is composed of micrite-rich wackestone, comprising one of two biofacies: 1) alternating …


Assessing Plastic Pollution On Shorelines And In Coastal Sediments, Victoria Madison Fulfer Jan 2024

Assessing Plastic Pollution On Shorelines And In Coastal Sediments, Victoria Madison Fulfer

Open Access Dissertations

Plastics have become pollutants around the world, entering the marine environment predominantly from many land-based sources. A small proportion of plastics in the marine environment also come from sea-based activities such as fishing, boating, and shipping. Once in the environment, the low density of most plastic polymers allows transport around the globe by winds, rivers, currents, waves, floodwaters, and tides. As a result, the ultimate fate of present and past plastic pollution is poorly constrained; however, much material in the sea is thought to accumulate in marine sediment over time.

Plastics in the environment have a wide range of morphologies …


Slope Unit Maker (Sumak): An Efficient And Parameter-Free Algorithm For Delineating Slope Units To Improve Landslide Modeling, Jacob B. Woodard, Benjamin B. Mirus, Nathan J. Wood, Kate E. Allstadt, Benjamin A. Leshchinsky, Matthew M. Crawford Jan 2024

Slope Unit Maker (Sumak): An Efficient And Parameter-Free Algorithm For Delineating Slope Units To Improve Landslide Modeling, Jacob B. Woodard, Benjamin B. Mirus, Nathan J. Wood, Kate E. Allstadt, Benjamin A. Leshchinsky, Matthew M. Crawford

Faculty, Staff, and Affiliated Publications--KGS

Slope units are terrain partitions bounded by drainage and divide lines. In landslide modeling, including susceptibility modeling and event-specific modeling of landslide occurrence, slope units provide several advantages over gridded units, such as better capturing terrain geometry, improved incorporation of geospatial landslide-occurrence data in different formats (e.g., point and polygon), and better accommodating the varying data accuracy and precision in landslide inventories. However, the use of slope units in regional (> 100 km2) landslide studies remains limited due, in part, to the large computational costs and/or poor reproducibility with current delineation methods. We introduce a computationally efficient algorithm …


Optimizing Field-Linked Simulations Of Dry Season Uptake And Monsoon Infiltration Within An Aspen-Mixed Conifer Forest, Raymond J. Hess Jan 2024

Optimizing Field-Linked Simulations Of Dry Season Uptake And Monsoon Infiltration Within An Aspen-Mixed Conifer Forest, Raymond J. Hess

Master's Theses

Climate models forecast that headwater catchments in the western U.S. will undergo a reduction in snowpack, early season snowmelt, and increases in evapotranspiration. The resulting extended dry season will stress vegetation in mountainous watersheds throughout the Upper Colorado River Basin. We investigate infiltration patterns and root water uptake in response to dry season disturbances within the East River watershed in Colorado. To do this, we collected soil cores, measured matric potential and sap flow, and monitored tree xylem and soil for stable isotopes of water (2H, 18O) in two soil profiles to 90 cm depth (with three Engelmann spruce and …


108, Scott Brande Jan 2024

108, Scott Brande

All 3D Rock Models

Model 108 - peridotite - igneous rock

SketchFab link: https://sketchfab.com/3d-models/108-de2d9c9cc2b1434b981d025a7e9fb2fc


Basal Topography And Carbon Accumulation Rate Of A Rare Northern California Coastal Fen, Sarah Leidinger Jan 2024

Basal Topography And Carbon Accumulation Rate Of A Rare Northern California Coastal Fen, Sarah Leidinger

Cal Poly Humboldt theses and projects

Increasingly, the importance of peatlands as biodiversity hotpots, year-round water storage features, and significant carbon sinks are being recognized. Despite this, they are one of the most vulnerable ecosystems globally. While some peatland conservation and restoration initiatives are being developed, a greater understanding of small peatlands is needed to make management decisions. This study aims to determine the timing of peat formation, peat volume, and carbon accumulation rates of the Conspicuous Scoop Fen, a small (2.1-acre) fen near Bridgeville, California (~840 m.a.s.l.). During the summers of 2022 and 2023, I collected 39 m of peat cores at 14 sampling locations. …


150, Scott Brande Jan 2024

150, Scott Brande

All 3D Rock Models

Model 150 - pegmatite - igneous rock

SketchFab link: https://sketchfab.com/3d-models/150-135e099a4d4145848c7f26c0c2d5c438


190, Scott Brande Jan 2024

190, Scott Brande

All 3D Rock Models

Model 190 - sandstone - sedimentary rock

SketchFab link: https://sketchfab.com/3d-models/190-29d202409b1246a1b550db9c6f41b25c


220, Scott Brande Jan 2024

220, Scott Brande

All 3D Rock Models

Model 220 - slate - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/220-39857764278746049e60bd9238ed3891


247, Scott Brande Jan 2024

247, Scott Brande

All 3D Rock Models

Model 247 - schist - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/247-aea85a461ca2414489bd0b04a4df3bdcN


260, Scott Brande Jan 2024

260, Scott Brande

All 3D Rock Models

Model 260 - breccia - sedimentary rock

SketchFab link: https://sketchfab.com/3d-models/260-6711f31b529448739ead7cf0a33b94ee


262, Scott Brande Jan 2024

262, Scott Brande

All 3D Rock Models

Model 262 - breccia - sedimentary rock

SketchFab link: https://sketchfab.com/3d-models/262-5a77a879cec743c3b724644ce5490914


265, Scott Brande Jan 2024

265, Scott Brande

All 3D Rock Models

Model 265 - gneiss - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/265-9ea30b81d35c49d1bb066367002d1fac


271, Scott Brande Jan 2024

271, Scott Brande

All 3D Rock Models

Model 271 - marble - metamorphic rock

SketchFab link: https://sketchfab.com/3d-models/271-370135d0aba44ec38c87c827123db334


Assessing The Ore Mineralization Depth And Crustal History Of Plutons In Northeastern Washington Using Thermodynamic Modeling Of Wall Rock Assemblages, David William Miller Jan 2024

Assessing The Ore Mineralization Depth And Crustal History Of Plutons In Northeastern Washington Using Thermodynamic Modeling Of Wall Rock Assemblages, David William Miller

All Master's Theses

Critical minerals are essential for advanced technologies across all economic sectors, but domestic deposits are unconstrained and underutilized, leaving the U.S. economy vulnerable to disruption. In northeastern WA, several ore-bearing plutons may be a significant resource; however, their formation depths, a component responsible for ore genesis, are unknown. To constrain regional ore formation depths, the mineral assemblages of calc-silicate and pelitic rocks from the contact aureoles of two Cretaceous plutons, located in the Adams Mountain and Hunters (AMH) quadrangles in the hangingwall of the Kettle detachment fault (KDF), were quantitatively constrained with scanning electron microscopy and XMapTools and compared to …