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Full-Text Articles in Geology

A Methodology For The Creation Of Volcanic Gas Hazard Maps Using Satellite-Derived Sulfur Dioxide, Sanna J. Mairet Jan 2021

A Methodology For The Creation Of Volcanic Gas Hazard Maps Using Satellite-Derived Sulfur Dioxide, Sanna J. Mairet

Dissertations, Master's Theses and Master's Reports

Sulfur dioxide (SO2) gas has been shown to be detrimental to human and environmental health and is emitted continuously from anthropogenic and volcanic sources. Sulfur dioxide is the main target gas used for the detection of hazardous volcanic plumes due to its ease of detection by satellite sensors. However, quantitative information on potential ground-level exposure to volcanic SO2 (i.e., a volcanic gas ‘hazard map’) is currently unavailable for the vast majority of active volcanoes. Utilizing sulfur dioxide vertical column densities retrieved from the Ozone Monitoring Instrument on NASA’s Aura satellite, Gridded Population of the World v.4, planetary …


Origin And Distribution Of Diffuse Soil Co2 Gas Emissions Across Turrialba And Irazú Volcanoes, Costa Rica, Katie Nelson Jan 2021

Origin And Distribution Of Diffuse Soil Co2 Gas Emissions Across Turrialba And Irazú Volcanoes, Costa Rica, Katie Nelson

Dissertations, Master's Theses and Master's Reports

We characterized large-scale volatile emissions across the summit and flanks of the actively degassing Turrialba volcano, Costa Rica, using soil gas flux measurements and 13C isotopes. The objectives of this study were the following: 1) to monitor changes in the magmatic activity and identify source contributions over Turrialba using measurements of CO2 soil gas emissions since the volcano last erupted in 2014-2015, and 2) to identify the location and extent of magma at depth, and the structures that allow gas transport to the surface. Degassing at the summit is concentrated along one normal fault lineament, the trace of …


2021 Nebraska Water Leaders Academy Final Report, Mark E. Burbach, Robert Matthew Joeckel, Brooke Mott, Gina S. Matkin Jan 2021

2021 Nebraska Water Leaders Academy Final Report, Mark E. Burbach, Robert Matthew Joeckel, Brooke Mott, Gina S. Matkin

Conservation and Survey Division: Faculty and Staff Publications

Seventeen participants completed the 2021 Water Leaders Academy bringing the total number of graduates to 153 since the inception of the program in 2011. Assessments of participants’ transformational leadership skills, champion of innovation skills, water knowledge, engagement with water issues, civic capacity, entrepreneurial leadership behaviors, and boundary spanner abilities showed significant increases over the course of the year, according to both the participants and their raters. Feedback from the participants was highly positive and constructive. Academy planners are addressing participant concerns. Only minor changes are planned for the 2022 Academy curriculum. Results of the program assessment indicate that the curriculum …


Annual Report 2020 Conservation And Survey Division, Robert Matthew Joeckel Jan 2021

Annual Report 2020 Conservation And Survey Division, Robert Matthew Joeckel

Conservation and Survey Division: Faculty and Staff Publications

The Conservation and Survey Division (Nebraska Geological Survey), the natural resource survey component of the School of Natural Resources, is a unique, multi-disciplinary research, service and data-collection organization established by state statute in 1921.

The Division's mission is to investigate and record information about Nebraska's geologic history, its rock and mineral resources, the quantity and quality of its water resources, land cover and other aspects of its geography, as well as the nature, distribution and uses of its soils.


Terrestrial Ecological Risk Analysis Via Dietary Exposure At Uranium Mine Sites In The Grand Canyon Watershed (Arizona, Usa), Jo Ellen Hinck, Danielle Cleveland, Bradley E. Sample Jan 2021

Terrestrial Ecological Risk Analysis Via Dietary Exposure At Uranium Mine Sites In The Grand Canyon Watershed (Arizona, Usa), Jo Ellen Hinck, Danielle Cleveland, Bradley E. Sample

United States Geological Survey: Staff Publications

The U.S. Department of the Interior recently included uranium (U) on a list of mineral commodities that are considered critical to economic and national security. The uses of U for commercial and residential energy production, defense applications, medical device technologies, and energy generation for space vehicles and satellites are known, but the environmental impacts of uranium extraction are not always well quantified. We conducted a screening-level ecological risk analysis based on exposure to miningrelated elements via diets and incidental soil ingestion for terrestrial biota to provide context to chemical characterization and exposures at breccia pipe U mines in northern Arizona. …


Metabarcoding Assays For The Detection Of Freshwater Mussels (Unionida) With Environmental Dna, Katy E. Klymus, Catherine A. Richter, Nathan Thompson, Jo Ellen Hinck, Jess W. Jones Jan 2021

Metabarcoding Assays For The Detection Of Freshwater Mussels (Unionida) With Environmental Dna, Katy E. Klymus, Catherine A. Richter, Nathan Thompson, Jo Ellen Hinck, Jess W. Jones

United States Geological Survey: Staff Publications

Freshwater mussels of the order Unionida are a widely distributed taxon that are important in maintaining freshwater ecosystems and are also highly imperiled throughout the world. Monitoring of mussel populations with environmental DNA (eDNA) is an attractive alternative to traditional methods because it is noninvasive and requires less labor and taxonomic knowledge from field personnel. We developed eDNA metabarcoding assays specific to freshwater mussels and tested them at six sites in the Clinch River, located in the southeastern United States. Our objective was to determine the utility of eDNA metabarcoding for future monitoring of mussel populations and restoration efforts in …


The Marine Terraces Of Santa Cruz Island, California: Implications For Glacial Isostatic Adjustment Models Of Last-Interglacial Sea-Level History, Daniel R. Muhs, R. Randall Schumann, Lindsey T. Groves, Kathleen R. Simmons, Christopher R. Florian Jan 2021

The Marine Terraces Of Santa Cruz Island, California: Implications For Glacial Isostatic Adjustment Models Of Last-Interglacial Sea-Level History, Daniel R. Muhs, R. Randall Schumann, Lindsey T. Groves, Kathleen R. Simmons, Christopher R. Florian

United States Geological Survey: Staff Publications

Glacial isostatic adjustment (GIA) models hypothesize that along coastal California, last interglacial (LIG, broadly from ~130 to ~115 ka) sea level could have been as high as +11 m to +13 m, relative to present, substantially higher than the commonly estimated elevation of +6 m. Areas with low uplift rates can test whether such models are valid. Marine terraces on Santa Cruz Island have previously been reported to occur at low (<10 m) elevations, but ages of many such localities are not known. Using lidar imagery as a base, marine terraces on Santa Cruz Island were newly mapped, elevations were measured, fossils were collected for U-series dating (corals), strontium isotope compositions and amino acid geochronology (mollusks), and paleozoogeography (all taxa). Sr isotope compositions of mollusks from the highest of three marine terraces give ages of ~2.5 Ma to 1.9 Ma, along with Pliocene ages, fromshells interpreted to be reworked. U-series ages of corals fromthewestern part of the island indicate that low-elevation terraces north of the Santa Cruz Island fault correlate to the LIG. Where corals are lacking, amino acid ratios and faunal aspects support terrace correlation to the LIG high stand of sea. Elevations of most terrace localities north of the east-west trending Santa Cruz Island fault, in both thewestern and eastern parts of the island, range from5.75mto 8mabove sea level, well belowthe modeled paleo-sealevel range. Subsidence is ruled out as a mechanism for explaining the lower-than-modeled elevations, because higher-elevation terraces are present alongmuch of the Santa Cruz Island coast north of the fault, indicating longterm tectonic uplift. The low elevations of the LIG terrace fragments are, however, consistent with a low rate of uplift derived from the higher, ~2.5–1.9 Ma terrace. A number of other localities on the Pacific Coast, also dated to the LIG, have marine terrace elevations below the modeled level. GIA models may have overestimated last interglacial sea level by a substantial amount and need to be revised if used for forecasts for future sea-level rise.


Workshop Outcomes Report: 1st International Workshop On Seismic Resilience Of Arctic Infrastructure And Social Systems, Majid Ghayoomi, Katharine Duderstadt, Alexander Kholodov, Alexander Shiklomanov, Matthew Turner, Elham Ajorlou Jan 2021

Workshop Outcomes Report: 1st International Workshop On Seismic Resilience Of Arctic Infrastructure And Social Systems, Majid Ghayoomi, Katharine Duderstadt, Alexander Kholodov, Alexander Shiklomanov, Matthew Turner, Elham Ajorlou

Faculty Publications

No abstract provided.


Diatoms And Their Response To Tectonic Gateway Changes: Case Studies From Southern Hemisphere Sites, Jason James Coenen Jan 2021

Diatoms And Their Response To Tectonic Gateway Changes: Case Studies From Southern Hemisphere Sites, Jason James Coenen

Graduate Research Theses & Dissertations

This dissertation covers three major transitions in Earth's climate system throughout theCenozoic (the past 65 million years of Earth's history). The progressive breakup of the super continent Pangea and the ultimate change in ocean circulation (and redistribution of heat) as a result of tectonic events dating back to the Mesozoic, primed Earth's climate system for cooling and ultimately bipolar glaciation. Climate transitions in three distinct environments were studied using absolute diatom abundance, diatom assemblages, and geochemical tracers of diatoms (i.e., biogenic silica weight%). Two geographic regions are the focus of this dissertation work. Region one is the Ross Embayment of …


Hydrocarbons In The Niobrara Formation, Powder River Basin, Northeast Wyoming, From Geophysical Well Logs, Jennifer Shilo James Jan 2021

Hydrocarbons In The Niobrara Formation, Powder River Basin, Northeast Wyoming, From Geophysical Well Logs, Jennifer Shilo James

Graduate Research Theses & Dissertations

The Powder River Basin, located in Wyoming, is a moderate producer of hydrocarbons with production hovering around 100 million barrels of oil per year. Recently the Niobrara Formation has garnered attention for hydrocarbon exploration and production using both conventional and unconventional drilling. A quick-look method for evaluating organic content, using either existing or real time data sets gathered from geophysical well logs, provides an opportunity to rapidly, accurately, and economically assess the formation’s organic content and thus hydrocarbon bearing potential. The popular Schmoker method determines organic content by relating gamma ray intensity to formation density. It has been successfully employed …


Alteration Reactions In A Hornblende-Biotite-Anthophyllite-Fluid System: Implications For Cu-Au Ore Deposits, James Mitchell Lightner Jan 2021

Alteration Reactions In A Hornblende-Biotite-Anthophyllite-Fluid System: Implications For Cu-Au Ore Deposits, James Mitchell Lightner

Graduate Research Theses & Dissertations

High-grade porphyry Cu-Au ore deposits are typically contained in the potassic alteration zone, which forms through the alteration of preexisting country rock by a magmatic volatile phase (MVP) exsolved from an igneous intrusion. The MVP is a H2O dominant phase that contains high concentrations of NaCl, KCl, FeCl2, HCl, sulfur (as H2S or SO2) and minor concentrations of metals. The minerals in the potassic alteration zone are predominantly K-feldspar and biotite with a shreddy texture. Shreddy biotite forms from the replacement of prismatic-tabular shaped hornblende crystals, resulting in a characteristic shreddy texture. The alteration of hornblende to biotite can neutralize …


Investigation Of A Possible Cretaceous-Paleogene Boundary Layer In The Hell Creek Formation Near Ekalaka, Montana, U.S.A., Joshua Marvin Schwartz Jan 2021

Investigation Of A Possible Cretaceous-Paleogene Boundary Layer In The Hell Creek Formation Near Ekalaka, Montana, U.S.A., Joshua Marvin Schwartz

Graduate Research Theses & Dissertations

The Hell Creek Formation is known for its abundant vertebrate fossils from the end of the Cretaceous. Its internal stratigraphy is poorly defined and it is therefore difficult to determine the precise stratigraphic location of a paleontological feature. This challenge could be overcome if a consistently appearing easily recognizable time horizon, such as the Chicxulub impact debris, or a well defined formational contact could be identified over a wide area of the Hell Creek Formation exposure, but these have been difficult to establish in some localities. The Carthage Institute of Paleontology (CIP) has collected Hell Creek specimens near Ekalaka, Montana …


Genesis Of Trondhjemite By Low-Pressure Fraction Anatexis Of Hornblende-Gabbro At Alvand Plutonic Complex (Hamedan, Nw Iran): Insights From Geochemical Modelling., Federico Lucci, Adel Saki, Mirmohammad Miri, Ahmad Rabiee, John C. White Jan 2021

Genesis Of Trondhjemite By Low-Pressure Fraction Anatexis Of Hornblende-Gabbro At Alvand Plutonic Complex (Hamedan, Nw Iran): Insights From Geochemical Modelling., Federico Lucci, Adel Saki, Mirmohammad Miri, Ahmad Rabiee, John C. White

EKU Faculty and Staff Scholarship

Amphibole-dominated dehydration melting of gabbro is the primary process responsible for the genesis of adakites, low-K tonalites, modern trondhjemites, and plagiogranites aswell as Archean tonalite-trondhjemite-granodiorite suites that represent the earliest examples of continental crust. Previous literature has mostly focused on the role of Al-rich amphibole during anatexis of a mafic source and many of these studies have investigated this process through experimental melting runs. However, due to experimental boundary conditions, little is known about partial melting of amphibole-bearing mafic rock at temperatures < 800°C for upper crustal conditions (pressure < 500 MPa). Classic and forward thermobarometric modelling suggests that in situ trondhjemite leucosomes, hosted by Cheshmeh-Ghasaban mafic metatexites (Alvand Plutonic Complex, Hamedan, NW Iran), represent a rare natural case study of a low-temperature incipient amphibole-dominated anatectic event of a mafic source with a primary assemblage (Pl+Hbl+Cpx+Bt+Opx) typical of a hornblende-bearing gabbroic rock.


Trondhjemite Leucosomes Generated By Partial Melting Of A Hornblende-Gabbro (Alvand Plutonic Complex, Hamedan, Nw Iran), Adel Saki, Federico Lucci, Mirmohammad Miri, John C. White Jan 2021

Trondhjemite Leucosomes Generated By Partial Melting Of A Hornblende-Gabbro (Alvand Plutonic Complex, Hamedan, Nw Iran), Adel Saki, Federico Lucci, Mirmohammad Miri, John C. White

EKU Faculty and Staff Scholarship

This work describes the petrogenesis of in situ and in-source trondhjemite leucosomes generated by low-degree partial melting of the Jurassic Cheshmeh-Ghasaban hornblende-gabbros in the northern Alvand batholith (Hamedan, NW Iran). These leucosomes occur in a metatexite migmatite as patches, net-structures, veinlets, and dikes at scales ranging from a few millimetres to a few metres. They have high SiO2 (mean ≈ 78 wt%) and Na2O (4–5 wt%) with low Al2O3 (wt%), K2 O (


Volcanological Evolution Of Pantelleria Island (Strait Of Sicily) Peralkaline Volcano: A Review, Silvio G. Rotolo, Stéphane Scaillet, Fabio Speranza, John C. White, Rebecca Williams, Nina J. Jordan Jan 2021

Volcanological Evolution Of Pantelleria Island (Strait Of Sicily) Peralkaline Volcano: A Review, Silvio G. Rotolo, Stéphane Scaillet, Fabio Speranza, John C. White, Rebecca Williams, Nina J. Jordan

EKU Faculty and Staff Scholarship

Pantelleria volcano has a particularly intriguing evolutionary history intimately related to the peralkaline composition of its explosively erupted magmas. Due to the stratigraphic complexity, studies over the last two decades have explored either only the pre-Green Tuff ignimbrite volcanism or the post-Green Tuff activity. We here focus on the whole evolutionary history, detailing the achievements since the first pioneering studies, in order to illustrate how the adoption and integration of progressively more accurate methods (40Ar/39Ar, paleomagnetism, petrography, and detailed field study) have provided many important independent answers to unresolved questions. We also discuss rheomorphism, a distinct feature at Pantelleria, at …


Analysis Of Vibracores From The New Hampshire Continental Shelf From 1984 And 1988, Larry G. Ward, Rachel C. Morrison, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2021

Analysis Of Vibracores From The New Hampshire Continental Shelf From 1984 And 1988, Larry G. Ward, Rachel C. Morrison, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

During this study, the twenty-three vibracores taken in 1984 and 1988 were reexamined, original descriptions verified and significantly expanded, and the cores sampled to provide complete grain size data (i.e. the original sediment grain size analyses were limited). The vibracores were grouped by location with respect to major physiographic features (geoforms) or surficial sediment type including Offshore Marine-Modified Glacial Features (Drumlins and Lodgement Till Deposits), Northern Sand Body, Isles of Shoals, Nearshore Marine-Modified Glacial Features (Eskers and Drumlins), Nearshore Sheet Sand, and Offshore Seafloor Plain.

The Northern Sand Body (NSB), located near the Isles of Shoals ~10 km from shore, …


New Hampshire And Vicinity Continental Shelf: Sand And Gravel Resources, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2021

New Hampshire And Vicinity Continental Shelf: Sand And Gravel Resources, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

The continental shelf off New Hampshire (NH) has extensive marine-modified glacial deposits and associated shoals. These features are potential targets for sand and gravel resources for beach nourishment and other efforts to build coastal resiliency. The distribution of sand and gravel deposits was evaluated based on the synthesis of relatively recent high-resolution bathymetry, new surficial sediment and geoform maps, and an extensive data archive that includes over ~1280 km of seismic profiles, ~750 grain size analyses, and 23 vibracores. This work heavily utilizes the results of previous research on mineral resources on the NH shelf by Birch (1984) …


Surficial Geology Of The Continental Shelf Off New Hampshire: Morphologic Features And Surficial Sediment, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani, Rachel C. Morrison Jan 2021

Surficial Geology Of The Continental Shelf Off New Hampshire: Morphologic Features And Surficial Sediment, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani, Rachel C. Morrison

Center for Coastal and Ocean Mapping

The continental shelf off New Hampshire (NH) in the Western Gulf of Maine (WGOM) is extremely complex and includes extensive bedrock outcrops, marine-modified glacial deposits, marine-formed shoals, seafloor plains, and associated features that are composed of a range of sediment types from mud to gravel. Furthermore, the physiography and composition of the seafloor frequently changes dramatically over relatively short distances (tens of meters). The complexity of the WGOM seafloor results from the interplay of glaciations, sea-level fluctuations, and marine processes (waves and currents). High-resolution multibeam echosounder (MBES) bathymetry and backscatter surveys, along with ground truth consisting of archived seismic reflection …


Seasonal Changes In Sediment Grain Size Of New Hampshire Atlantic Beaches, Larry G. Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison Jan 2021

Seasonal Changes In Sediment Grain Size Of New Hampshire Atlantic Beaches, Larry G. Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison

Center for Coastal and Ocean Mapping

The beaches along the New Hampshire Atlantic coast are essential to the local and regional economy and are one of the major attractions of the seacoast. Beyond their economic importance, the beaches also have great aesthetic and ecological value that are vital to the character and history of New Hampshire. Unfortunately, climate change and an acceleration in sea-level rise, coupled with a major reduction in sediment supply and extensive development (including engineering structures along the coast), has led to loss of elevation and narrowing of many of the beaches. The forecast is that these trends will continue and likely become …


Erosion And Accretion Trends Of New Hampshire Beaches From December 2016 To March 2020: Results Of The Volunteer Beach Profile Monitoring Program, Larry G. Ward, Rachel C. Morrison, Alyson L. Eberhardt, Wellsley J. Costello, Zachary S. Mcavoy, Caitlin P. Mandeville Jan 2021

Erosion And Accretion Trends Of New Hampshire Beaches From December 2016 To March 2020: Results Of The Volunteer Beach Profile Monitoring Program, Larry G. Ward, Rachel C. Morrison, Alyson L. Eberhardt, Wellsley J. Costello, Zachary S. Mcavoy, Caitlin P. Mandeville

Center for Coastal and Ocean Mapping

New Hampshire Atlantic beaches were monitored from December 2016 to March 2020 to determine seasonal changes in morphology and elevation, assess the response of the beaches to storms with respect to erosion and subsequent recovery, and develop a baseline to determine long-term trends in beach size, elevation, and position. A unique aspect of this study was the involvement of community volunteers working together with the University of New Hampshire (UNH) Center for Coastal and Ocean Mapping, UNH Cooperative Extension, New Hampshire Sea Grant, and the New Hampshire Geological Survey. The monitoring network consisted of thirteen stations located at six of …


Investigation Of Statistical Seismology In Thailand-Laos-Myanmar Borders, Manunchaya Neanudorn Jan 2021

Investigation Of Statistical Seismology In Thailand-Laos-Myanmar Borders, Manunchaya Neanudorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this research is to understand more about the statistical seismology of the Thailand-Laos-Myanmar border in order to monitor earthquake activity and locate potentially dangerous area. The seismicity data was collected from the Thailand Meteorological Department. Following that, the catalog's homogeneity and completeness were improved. The first step is to identify the earthquake activity by using the adaptive frequency-magnitude distribution. The results are that Nan province, Thailand, and south Luang Prabang, Laos are the highest activity areas which can generate a maximum magnitude of 5.1 ML, 5.6 ML, 6.3 ML, and 6.7 ML in 5, 10, 30, 50 …


Analysis Of Ancient Storm Deposits Along Coastal Areas Of Andaman Sea, Thailand And Coastal Areas Of South China Sea, Vietnam, Stapana Kongsen Jan 2021

Analysis Of Ancient Storm Deposits Along Coastal Areas Of Andaman Sea, Thailand And Coastal Areas Of South China Sea, Vietnam, Stapana Kongsen

Chulalongkorn University Theses and Dissertations (Chula ETD)

The frequency of high energy storm and tsunami events is crucial for apprehending the vulnerability of coastal communities. Identifying and dating sedimentary evidence deposited by such high energy events can assist in the planning and installation of suitable protection measurements. The Andaman Sea coast of Thailand is particularly vulnerable to such events as illustrated by the 2004 Indian Ocean Tsunami (2004 IOT) and the South China Sea coast of Vietnam has been experienced from the past severe storm event. Here, the authors study the high energy sediments. The selected area of Andaman Sea coast Thailand is Laem Son National park, …


Trace Elements And Color-Causing Role In Spinel And Tanzanite, Teerarat Pluthametwisute Jan 2021

Trace Elements And Color-Causing Role In Spinel And Tanzanite, Teerarat Pluthametwisute

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research is aimed to investigate the significant trace elements and their color-causing roles in tanzanite and spinels (7 color varieties) by focusing on their concentrations, valencies, and site occupancy since no palpable research has been reported previously either before or after heating of both gems. According to this finding, natural tanzanites usually show strongly trichroic colors of violet, blue, and brown in different directions. However, this characteristic is easily changed to violet-blue dichroism after heat treatment. As the result, the violet-blue absorption band (centered around 450–460 nm) is obviously decreased after heating, and XAS analysis indicates the higher valency …


Stratigraphy And Paleoenvironment Of Thong Pha Phum Group In Kanchanaburi Province, Warunee Maneerat Jan 2021

Stratigraphy And Paleoenvironment Of Thong Pha Phum Group In Kanchanaburi Province, Warunee Maneerat

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purposes of this study are to establish the detail lithology, stratigraphy, lithofacies and systematic paleontology of marine Silurian-Devonian sedimentary rocks of the Thong Pha Phum Group in Ban Tha Kraden, Si Sawat District, Kanchanaburi Province, and to interpret and reconstruct its depositional environment. The Thong Pha Phum Group is well exposed in the study area. It consists mainly of shale, siltstone, sandstone, limestone, argillaceous limestone, calcareous shale, calcareous mudstone, and laminated mudstone with the many fossils such as graptolites, tentaculites, ostracods, brachiopods, nautiloids and trilobites. These strata are conformably underlain by the Thung Song Group (Ordovician age) and are …


The Pilot Knob Magnetite, Pilot Knob Hematite, And Shepherd Mountain Iron Oxide Deposits In Southeast Missouri -- Local Expressions Of A Magmatic-Hydrothermal Plumbing System?, Bolorchimeg N. Tunnell Jan 2021

The Pilot Knob Magnetite, Pilot Knob Hematite, And Shepherd Mountain Iron Oxide Deposits In Southeast Missouri -- Local Expressions Of A Magmatic-Hydrothermal Plumbing System?, Bolorchimeg N. Tunnell

Doctoral Dissertations

“The Southeast Missouri Iron Metallogenic Province in the Midwestern USA contains seven major and several minor IOA/IOCG-type deposits, all of which are spatially associated with the early Mesoproterozoic (1.50-1.44 Ga) magmatism in the St. Francois Mountains terrane. This Ph.D. project focuses on the Pilot Knob deposits, i.e., the deeper largely massive Pilot Knob Magnetite (PKM) and the shallower Pilot Knob Hematite (PKH) deposits, and the Shepherd Mountain deposit that are located less than 2.1 km distance from one another. The first precise age for the formation of the PKM ore is constrained at 1438±5.8 Ma using apatite U-Pb method. Petrographic …


Independent, Semi-Automated Classification Of Petrographic Features In Volcanic Rocks Using Fiji And Weka, Holly Danielle Pettus Jan 2021

Independent, Semi-Automated Classification Of Petrographic Features In Volcanic Rocks Using Fiji And Weka, Holly Danielle Pettus

Graduate Theses, Dissertations, and Problem Reports (ETD)

Traditional methods of collecting quantitative petrographic data from thin sections (modal mineralogy, size distribution, shapes, etc.) are time- and labor-intensive, and rarely have sample sizes adequate to statistically describe complex rocks (i.e. volcanic rocks). Although manual counting and measurements are now routinely supplemented by digital image analysis, the majority of quantitative petrographic studies still go through a manual digitization stage where object classes are traced before further analyses. This is a major rate-limiting step that reproduces the same problems of small n-values resulting from significant effort. We have valuated the potential and limitations of using the Trainable Weka Segmentation (TWS) …


A Snapshot Of Ancient Microbial Life: Microorganisms And Organic Compounds In Primary Fluid Inclusions In Bedded Halite, Neoproterozoic Browne Formation Of Central Australia, Sara I. Schreder-Gomes Jan 2021

A Snapshot Of Ancient Microbial Life: Microorganisms And Organic Compounds In Primary Fluid Inclusions In Bedded Halite, Neoproterozoic Browne Formation Of Central Australia, Sara I. Schreder-Gomes

Graduate Theses, Dissertations, and Problem Reports (ETD)

Modern shallow brine environments contain an abundance of microorganisms. Microorganisms, mineral crystals, and air bubbles can be trapped with those brines in primary fluid inclusions in bedded halite as it grows in shallow saline surface waters. Primary fluid inclusions and their contents can be preserved, unaltered, for millions of years.

The ~830 million-year-old Browne Formation of central Australia contains intervals of bedded halite with unaltered primary fluid inclusions. Intervals of bedded halite were sampled in the Empress 1A core from ~1480 m – 1520 m depths. Here, I used petrography to describe suspect microorganisms and organic compounds that were trapped …


Petrographic And Core Analysis Of The Jurassic Norphlet Formation: A Case Study In The Lithofacies Control Of Diagenesis And Porosity In The Flomaton Field, Al, Jarrett Thomas Smith Jan 2021

Petrographic And Core Analysis Of The Jurassic Norphlet Formation: A Case Study In The Lithofacies Control Of Diagenesis And Porosity In The Flomaton Field, Al, Jarrett Thomas Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

This study includes a sedimentologic and petrographic study of cores and thin-sections from the Jurassic Norphlet Formation in the Flomaton Field in southern Alabama to define a specific paragenetic history of each facies encountered and to identify key controls on reservoir quality. Eolian dune, nearshore, sand flat, and wadi facies were likely encountered in Norphlet core and thin-section samples that displayed a high degree of heterogeneity between them in terms of porosity, grain contacts, cement abundance/type, intergranular volume, and overall diagenetic processes. These distinct petrographic differences suggest that the paragenesis in the Flomaton Field is primarily facies controlled. The eolian …


Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright Jan 2021

Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright

Theses

Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …


Structural And Thermochronologic Evidence Of Paleogene-Neogene Faulting And Exhumation Of The Klamath Mountain Province, Taylor C. Team Jan 2021

Structural And Thermochronologic Evidence Of Paleogene-Neogene Faulting And Exhumation Of The Klamath Mountain Province, Taylor C. Team

Cal Poly Humboldt theses and projects

The Klamath Mountains Province (KMP), located at the southern end of the forearc of the Cascadia Subduction Zone, displays a distinct topographic and geologic signature. Compared to the forearc in the north, the KMP comprises Paleozoic-Mesozoic basement rocks with relatively high modern elevation and relief. This study investigates the pattern of rock cooling in the KMP by using thermochronology on plutons exhumed by faults and plutons outside of mapped faults. In this study, I target three regions in the KMP: the Ashland pluton offset by the Siskiyou Summit fault in the northeast KMP, the Grayback pluton in the northwest KMP, …