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Full-Text Articles in Physical Sciences and Mathematics

Toward A Greater Comprehension Of The Paraná Epicontinental Sea During The Late Paleozoic Ice Age: The Glacial And Postglacial Record In The Western Paraná Basin (Brazil) And The Kaokoveld Fjord Network (Namibia), Eduardo Luiz Menozzo Da Rosa Dec 2023

Toward A Greater Comprehension Of The Paraná Epicontinental Sea During The Late Paleozoic Ice Age: The Glacial And Postglacial Record In The Western Paraná Basin (Brazil) And The Kaokoveld Fjord Network (Namibia), Eduardo Luiz Menozzo Da Rosa

Theses and Dissertations

The late Paleozoic Ice Age (LPIA; 362 to 255 Ma) was an icehouse interval that drove substantial changes in Earth’s surficial systems. Numerous paradigms regarding aspects of the LPIA were established throughout ~150 years of research based primarily on the evolving state of knowledge in sedimentology. The near-field lithological evidence for widespread glaciation across sedimentary basins of Gondwana are the building blocks for comprehensive paleoclimatic, biologic, paleogeographic, and ice volume models. Nevertheless, the embodied glacial record from several late Paleozoic Gondwanan depocenters still rely on insufficient and/or outdated sedimentologic and stratigraphic studies, which can lead to misinterpretations in models built …


Testing The Use Of Anisotropy Of Magnetic Susceptibility (Ams) In Determining Genetic Origins Of Paleoproterozoic Diamictites, Miles A. Harbury May 2023

Testing The Use Of Anisotropy Of Magnetic Susceptibility (Ams) In Determining Genetic Origins Of Paleoproterozoic Diamictites, Miles A. Harbury

Theses and Dissertations

The Huronian Supergroup (2.4-2.1 Ga) in Ontario, Canada is widely accepted as an important stratigraphic interval for interpreting Paleoproterozoic climate. This is because it contains some of the oldest glaciogenic rocks on the planet. However, massive and poorly-stratified diamictites in the Gowganda Formation of the Huronian Supergroup have varying depositional interpretations among sedimentologists (subglacial, rainout, sediment gravity flow etc.). Diamictites can occur from a variety of processes and, therefore, proper depositional interpretation is essential for unraveling detailed environmental conditions at the time of deposition. Anisotropy of magnetic susceptibility (AMS) looks at the orientation of magnetic particles within a rock and …


Using Anisotropy Of Magnetic Susceptibility (Ams) To Identify A Tectonic Lineation In The Pulo Do Lobo Formation In The Southern Iberian Shear Zone Near Aracena, Spain, Devin Levang Dec 2022

Using Anisotropy Of Magnetic Susceptibility (Ams) To Identify A Tectonic Lineation In The Pulo Do Lobo Formation In The Southern Iberian Shear Zone Near Aracena, Spain, Devin Levang

Theses and Dissertations

The Southern Iberian Shear Zone (SISZ) is a Variscan-aged suture representing the closure of a small ocean basin during the Carboniferous. The SISZ is bounded on either side by the well-studied, relatively homogeneous Beja-Acebuches Metabasites (BAM) and the complex and heterogeneous accretionary metasedimentary rocks of the Pulo do Lobo (PdL). The SISZ underwent a combination of shortening and lateral shearing known as transpression. Despite a very well-developed tectonic foliation, kinematic interpretation in the PdL is made difficult by a lack of easily identifiable lineations. Anisotropy of magnetic susceptibility (AMS), a geophysical technique measuring the relative anisotropy of magnetic susceptibility axes …


Unraveling Deformation Mechanisms And Kinematics In Metasedimentary Rocks Along The Southern Iberian Shear Zone, Kayla P. Kopinski Dec 2022

Unraveling Deformation Mechanisms And Kinematics In Metasedimentary Rocks Along The Southern Iberian Shear Zone, Kayla P. Kopinski

Theses and Dissertations

The primary goal of this project is to document deformation mechanisms in quartz-rich rocks across a 100 m wide ductile shear zone to evaluate whether strain localization at the brittle-ductile transition is accompanied by variations in active or dominant deformation mechanisms. A secondary goal of this project is to evaluate whether the kinematic framework varies across a shear zone with a major rheological boundary. The Southern Iberian Shear Zone (SISZ), a major terrane bounding shear zone within the Iberian Massif, is an ideal location to study these questions because it is a regional scale shear zone currently exposed at the …


Strain Development And Partitioning Across A Transpressional Shear Zone Along A Quartzite- Metagabbro Contact In The Black Hills Uplift, South Dakota, Eric L. Schuemann Dec 2022

Strain Development And Partitioning Across A Transpressional Shear Zone Along A Quartzite- Metagabbro Contact In The Black Hills Uplift, South Dakota, Eric L. Schuemann

Theses and Dissertations

The Nemo region of South Dakota’s Black Hills offers an ideal location to study transpressional shear zones because it hosts an exposed Archean lithological boundary between two contrasting rheological units, the Boxelder Creek Quartzite (BCQ), a rift-depositional quartzite, and the Blue Draw Metagabbro (BDM), a metagabbro sill, deformed within a ductile shear zone that represents the beginning of main-phase formation of the North American continent as we know it today. The tectonic setting of the Black Hills is at the eastern edge of the Archean Wyoming province, located near the Trans-Hudson Orogeny suture zone that formed between the Wyoming and …


Stratigraphy, Sedimentology, And Deformational Significance Of Cambrian And Early Ordovician Strata Along The Southeast Wisconsin Arch, Allison Raeann Kusick Aug 2022

Stratigraphy, Sedimentology, And Deformational Significance Of Cambrian And Early Ordovician Strata Along The Southeast Wisconsin Arch, Allison Raeann Kusick

Theses and Dissertations

A detailed study of the stratigraphic units in and around the Wisconsin Arch of central and southeast Wisconsin are presented to refine the sedimentologic record and the geologic implications within the Cambrian and early Ordovician strata. The Cambrian and early Ordovician sediments in central and southeast Wisconsin unconformably overlie a topographic high composed of Precambrian basement rocks, called the Wisconsin Arch, and consist of various clastic deposits, dolostones, and several horizons of deformation. Bedrock cores, made available through the Wisconsin Geological and Natural History Survey (WGNHS), were analyzed, to understand sedimentation in the Cambrian and early Ordovician. My analyses focused …


Terrestrial Perspective On The Formation, Evolution, And Detection Of Zeolites In Lacustrine Environments On Early Mars, Gayantha Roshana Loku Kodikara May 2022

Terrestrial Perspective On The Formation, Evolution, And Detection Of Zeolites In Lacustrine Environments On Early Mars, Gayantha Roshana Loku Kodikara

Theses and Dissertations

This study evaluates the possible formation and evolution mechanisms of zeolites on early Mars with possible explanations for their limited detections using Earth analogs. This study focuses on the formation of zeolites in the closed basin lakes where the largest relatively pure concentrations of natural zeolites are found on Earth. Five working hypotheses were formulated to explore the limited detection of zeolites in closed basin lakes on Mars and different styles of scientific reasoning with suitable examples were used to test the independent, converging lines of inquiry. Zeolites may not be identifiable in certain locations on Mars using orbital data …


Alkalinity Enhanced Mass Reduction Of Uranium Contaminated Sediment, Cullen Edward Meurer May 2022

Alkalinity Enhanced Mass Reduction Of Uranium Contaminated Sediment, Cullen Edward Meurer

Theses and Dissertations

Uranium is a toxic and radioactive metal that is naturally occurring in the Earth’s crust. The uranium mining boom of the 1950’s produced many contaminated aquifers throughout the United States. Monitoring of groundwater data suggests that uranium concentrations may take 100’s of years to naturally attenuate to below the maximum contamination limit. This project examines a potential and novel remediation technique of groundwater contaminated with uranium through alkalinity enhanced desorption from the solid phase. Alkalinity enhances the desorption of uranium by complexing uranyl (UO22+) with Ca and CO3 which allows for further desorption. Since remediation is time consuming and expensive, …


Baseflow Variability Due To Changes In Climate, Basin Characteristics, And Groundwater Withdrawals In The State Of Wisconsin, Usa, Susan Borchardt May 2022

Baseflow Variability Due To Changes In Climate, Basin Characteristics, And Groundwater Withdrawals In The State Of Wisconsin, Usa, Susan Borchardt

Theses and Dissertations

ABSTRACT

BASEFLOW VARIABILITY DUE TO CHANGES IN CLIMATE,BASIN CHARACTERISTICS, AND GROUNDWATER WITHDRAWALS IN THE STATE OF WISCONSIN, USA

bySusan Borchardt The University of Wisconsin-Milwaukee, 2022 Under the Supervision of Professor Woonsup Choi

In Wisconsin, the number of high-capacity wells has increased substantially, and concerns have been raised about their impact on both groundwater levels and streamflow. At the same time Wisconsin’s climate has been changing, and both the annual precipitation (5%) and temperature (1.5oC) have been trending upward over the last 68 years and both are predicted to increase into the future. This study attempted to demonstrate the simultaneous effects …


Analyzing Weathering Patterns In Modern And Paleolake Deposits Of Tecopa, California: Implications For The Detection Of Paleolakes On Mars, Jason Benjamin Carman Dec 2021

Analyzing Weathering Patterns In Modern And Paleolake Deposits Of Tecopa, California: Implications For The Detection Of Paleolakes On Mars, Jason Benjamin Carman

Theses and Dissertations

This study focuses on two stratigraphic sections from the Tecopa paleolake and samples from the modern Tecopa and Amargosa River basins as a terrestrial analogue to Martian paleolakes. Previous work shows that the later stages of Pleistocene Lake Tecopa were highly alkaline and saline due to evaporation, which led to the formation of authigenic lacustrine minerals such as zeolites, clays, and precipitates that are potentially similar to Martian paleolakes. Paleolakes can provide information on past aqueous processes, such as the changes in the hydrologic cycle that a particular area experienced over the lifespan of a lake on Earth or Mars. …


A South Polar View Of Late Paleozoic Glaciation: Physical Sedimentology And Provenance Of Glacial Successions In The Tasmanian And Transantarctic Basins, Elizabeth Rosa Woodford Ives Dec 2021

A South Polar View Of Late Paleozoic Glaciation: Physical Sedimentology And Provenance Of Glacial Successions In The Tasmanian And Transantarctic Basins, Elizabeth Rosa Woodford Ives

Theses and Dissertations

The Late Paleozoic Ice Age (LPIA; ~ 374 – 256 Ma) is the longest Phanerozoic icehouse interval. this interval in Earth’s history was largely defined by extensive glaciation of the southern hemisphere at both polar and temperate latitudes. Glaciers are powerful climatic and geologic actors, especially during icehouse periods, and widespread glaciation can have a significant influence on both regional and global climate and geology. Therefore, constraining the characteristics of LPIA glaciers is essential to developing a global-scale understanding of this key climatic event in Earth’s history. The manuscripts in this dissertation examine the sedimentology, transport directions, stratigraphy, and detrital …


Fluid Flow And Deformation: Exploring The Relationships Between Fluid Flow, Deformation Mechanisms, Quartz Crystallographic Preferred Orientation Fabric Development, And Kinematics In The Willard Thrust Fault, Utah, Falyn Strey May 2021

Fluid Flow And Deformation: Exploring The Relationships Between Fluid Flow, Deformation Mechanisms, Quartz Crystallographic Preferred Orientation Fabric Development, And Kinematics In The Willard Thrust Fault, Utah, Falyn Strey

Theses and Dissertations

Thirty-four quartz-rich samples were collected across the Willard thrust fault in Utah to explore the effects that fluid has on faulting. In particular, the relationships between fluid, deformation mechanisms, crystallographic preferred orientation (CPO) fabric development, and kinematic vorticity were investigated. A petrographic analysis of all 34 samples determined the relative contributions of brittle fracturing, crystal plasticity, and diffusional processes along with their possible relation to fluid interaction. Crystal plasticity dominates throughout most of the field area except where significant contributions from diffusive deformation occurs in rocks with significant mica concentrations and fine grain sizes, especially those located near the fault. …


Fluvial And Sequence Stratigraphy Analysis Of The Hell Creek And Fort Union Formations To Test Models For Sedimentation Across The Cretaceous-Paleogene Boundary In Makoshika State Park, Glendive, Montana, Quintin Bendixen May 2021

Fluvial And Sequence Stratigraphy Analysis Of The Hell Creek And Fort Union Formations To Test Models For Sedimentation Across The Cretaceous-Paleogene Boundary In Makoshika State Park, Glendive, Montana, Quintin Bendixen

Theses and Dissertations

The Cretaceous-Paleogene Boundary outcrops extensively throughout Makoshika State Park in Glendive, Montana. A distinct change in sedimentation style occurs across the Cretaceous- Paleogene in the Williston Basin deposits found in eastern Montana and western North Dakota. The well documented Hell Creek Formation of the Upper Cretaceous period consists of fresh and brackish water influenced deposits on the western low-lying coast of the Western Interior Seaway. The overlying Fort Union Formation consists of coals and fluvial sandstone deposits. Geologic explanations for the depositional shift include tectonic forces of the Sevier/Laramide Orogeny to the west, The Cretaceous-Paleogene Extinction Event, and the advancement …


Analyzing Strain Localization, Kinematic Partitioning And Fluid Flow In The Pulo Do Lobo Metasedimentary Rocks Along The Southern Iberian Shear Zone, Andalucia, Spain, Nancy Alejandra Carman Dec 2020

Analyzing Strain Localization, Kinematic Partitioning And Fluid Flow In The Pulo Do Lobo Metasedimentary Rocks Along The Southern Iberian Shear Zone, Andalucia, Spain, Nancy Alejandra Carman

Theses and Dissertations

The Southern Iberian Shear Zone is a regional scale ductile shear zone that placed Beja-Acebuches metabasites over metapelite and quartzite rocks of the Pulo do Lobo Formation in a transpressional deformation with components of thrust and left-lateral movement. This project evaluates factors that contributed to strain localization at a variety of scales within the Pulo do Lobo formation, including lithologic variations, microstructures, and fluid flow. Additionally, microstructural data are used to test whether kinematic partitioning accompanied strain localization. Grain scale asymmetric indicators of sigma-type clasts, S-C fabrics, and asymmetric folds indicate dominant thrust motion. Strain intensity and metamorphic grade increase …


Surface Alteration In The Ölkelduháls, Nesjavellir, And Geysir Hydrothermal Systems, Iceland: Implications For Mars, Jordan Ludyan Dec 2020

Surface Alteration In The Ölkelduháls, Nesjavellir, And Geysir Hydrothermal Systems, Iceland: Implications For Mars, Jordan Ludyan

Theses and Dissertations

Silica- and sulfate-rich deposits observed by Mars Exploration Rover (MER) Spirit near Home Plate, Gusev crater, Mars, indicate alteration of Mars basalt by a diverse array of hydrothermal fluids and processes. Constraining the precise fluid conditions present at the time of deposition for these deposits on Mars relies on investigations of terrestrial hydrothermal systems that produce similar mineral assemblages. Alteration products and fluids collected from the Ölkelduháls, Nesjavellir, and Geysir hydrothermal areas in southern Iceland cover a wide range of end-member and intermediate fluid and alteration environments, and provide a means to compare the secondary minerals produced from different hydrothermal …


Sedimentology, Sequence Stratigraphy, And High-Precision U-Pb Age Constraints On The Late Paleozoic Ansilta Formation, Calingasta-Uspallata Basin, Nw Argentina, John Ethan Malone Dec 2020

Sedimentology, Sequence Stratigraphy, And High-Precision U-Pb Age Constraints On The Late Paleozoic Ansilta Formation, Calingasta-Uspallata Basin, Nw Argentina, John Ethan Malone

Theses and Dissertations

The Ansilta Formation, located several kilometers east of the Astronomical Observatory El Leoncito near Barreal, San Juan Province, Argentina was deposited during the late Mississippian to early Pennsylvanian. This succession includes glacimarine, nearshore, and fluvial systems deposited at the mid-Carboniferous portion of the late Paleozoic ice age within the Calingasta—Uspallata Basin on the western margin of the Protoprecordillera. The lower member of the Ansilta Formation is equivalent to the nearby Leoncito, Majaditas, and Hoyada Verde formations, and is composed of diamictite, conglomerates, sandstones, pebbly mudstones, and laminated mudstone. Glacial environments are unique in that facies changes occur as a result …


Late Paleozoic Climatic Reconstruction Of Western Argentina: Glacial Extent And Deglaciation Of Southwestern Gondwana, Kathryn N. Pauls Aug 2020

Late Paleozoic Climatic Reconstruction Of Western Argentina: Glacial Extent And Deglaciation Of Southwestern Gondwana, Kathryn N. Pauls

Theses and Dissertations

Throughout its history Earth has experienced both icehouse and greenhouse conditions. Shifts and transitions from one end member to the other are driven by numerous driving mechanisms on global, orbital and more local scales. In particular, the late Paleozoic ice age (LPIA) is thought to have been driven by global drivers such as the drift of the Gondwanan continent across the South Pole, fluctuations in atmospheric CO2 concentrations, and Milankovitch cycles. It was also affected by more local and regional drivers such as active tectonism along accretionary margins and changes in atmospheric and oceanic circulation patterns. South American Gondwana provides …


Water Chemistry And Lake Dynamics Of Laguna Bacalar, Quintana Roo, Mexico, Ryan Matzuk Aug 2020

Water Chemistry And Lake Dynamics Of Laguna Bacalar, Quintana Roo, Mexico, Ryan Matzuk

Theses and Dissertations

Laguna Bacalar in the Quintana Roo region is the second largest lake in Mexico and contains freshwater derived solely from groundwater. Local geology on the Yucatan Peninsula is karstic and the southern shoreline of Laguna Bacalar is spotted with a handful of cenotes that contribute substantial amounts of inflowing groundwater to the lake. This is shown by sonde profile data taken in one of the largest cenotes in the area. Outflow is dominated by a surface water outlet in the southern portion of the lake and an unknown amount of outflowing groundwater. During January of 2017 through 2019, UWM researchers …


Characterization Of Water Pathways And Hydrolytic Weakening Within Naturally Deformed Quartz Grains Along The Willard Thrust Fault, Utah, Charles Alexander Martin May 2020

Characterization Of Water Pathways And Hydrolytic Weakening Within Naturally Deformed Quartz Grains Along The Willard Thrust Fault, Utah, Charles Alexander Martin

Theses and Dissertations

Evidence of water infiltration was examined in naturally deformed quartzite clasts from diamictite of the Mineral Fork Formation sampled from Antelope Island in the Great Salt Lake, Utah. The diamictite deformed via subsimple shear in the footwall of the Willard thrust fault and displays spatial variations in strain intensity. Evidence of water infiltration was investigated utilizing three complimentary techniques: standard petrographic microscopy to identify microstructures and interpret deformation mechanisms; scanning electron microscopy cathodoluminescence (SEM-CL) to create maps of healed microfractures and subgrain boundaries related to pathways of fluid infiltration; and synchrotron-source Fourier-transform infrared spectroscopy (FTIR) to create micron-scale water absorbance …


Simulating The Effects Of Urbanization And Climate Change On Ground Water Recharging Using The Usgs Precipitation And Runoff Modelling System (Prms), Kenneth Oanes May 2020

Simulating The Effects Of Urbanization And Climate Change On Ground Water Recharging Using The Usgs Precipitation And Runoff Modelling System (Prms), Kenneth Oanes

Theses and Dissertations

The Root River watershed, located in southeastern Wisconsin, was selected to be the subject of a study modeling the impacts of urbanization and climate change on groundwater recharge. Historical and projected (2035) land use data for the study area was sourced from the Southeast Wisconsin Regional Planning Committee (SEWRPC). The USGS Precipitation and Runoff Modelling System (PRMS) was selected to estimate recharge from a 35-year period of historical climate data (1980-2014). PRMS was run for the full 35-year time period under each land-use scenario and model outputs for evapotranspiration (ET), runoff, and recharge were calculated on a daily time-step.

Model …


A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung May 2020

A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung

Theses and Dissertations

Microbialites are carbonate organosedimentary deposits formed by benthic microbial communities that trap and bind detrital sediments, and/or inorganic and biologically influenced calcification. Any ferromagnetic particles incorporated into the microbialite structure have the potential to preserve variations in Earth’s magnetic field. A paleomagnetic record in microbialites would be useful for reconstructing the geomagnetic field because it may record at a high temporal resolution based on estimated growth rates, thus preserving relatively short-period variations of the Earth’s magnetic field. In addition, microbialites can be found in the geologic record going back ~3.5 Ga, hence potentially providing information on very ancient variations in …


The Dynamics And Speciation Of Arsenic In Drinking Water Wells In Eastern Wisconsin, Evvan Plank Dec 2019

The Dynamics And Speciation Of Arsenic In Drinking Water Wells In Eastern Wisconsin, Evvan Plank

Theses and Dissertations

Arsenic typically develops in Eastern Wisconsin groundwater as a result of oxidation of sulfide bearing minerals in the limestone bedrock (Schreiber et al. 2000). Naturally occurring arsenic exists in groundwater as oxyanions which have two oxidation states, As(III) and As(V). Under ambient pH conditions As(V) is primarily present as an anion (i.e., H2AsO4-) while As(III) tends to be uncharged (i.e., H3AsO3), making it much more difficult to remove through the existing treatment techniques such as adsorption and reverse osmosis (RO). Although many studies exist establishing arsenic concentrations across Wisconsin, there is a lack of investigations into the concentrations of each …


Sedimentological And Geochemical Analysis Of Deep-Water Deposits In The Mojón De Hierro Formation At Arroyo Garrido, Tepuel-Genoa Basin, Patagonia, Argentina, Natalie Beatrice Mcnall Aug 2019

Sedimentological And Geochemical Analysis Of Deep-Water Deposits In The Mojón De Hierro Formation At Arroyo Garrido, Tepuel-Genoa Basin, Patagonia, Argentina, Natalie Beatrice Mcnall

Theses and Dissertations

The Earth has had multiple Phanerozoic glacial intervals but the Late Paleozoic Ice Age (LPIA) was its longest and most extensive, lasting from the Late Devonian (~372 Ma) until the Late Permian (~254 Ma). The LPIA is the last complete climate shift from a greenhouse to icehouse and back to a greenhouse state and the only one to occur on a biologically complex Earth. Therefore, it provides perspectives on deep-time climatic transitions, the parameters controlling them, and the Earth’s physical, chemical and biological responses to such climate changes. Research on mid to high-latitude deposits in Gondwana provides evidence that the …


Testing The Late Paleozoic Ice Volume Paradox In The Southernmost Paraná Basin, Brazil, Nicholas David Fedorchuk May 2019

Testing The Late Paleozoic Ice Volume Paradox In The Southernmost Paraná Basin, Brazil, Nicholas David Fedorchuk

Theses and Dissertations

The late Paleozoic ice age (LPIA; ~372-259 Ma) was the last complete transition from icehouse to greenhouse conditions on a fully vegetated Earth, making it a relevant analog for modern Earth systems. High frequency glacioeustatic fluctuation of ~100-200 m during the late Paleozoic are described by some authors in low paleolatitude basins and attributed to the orbitally-driven, waxing and waning of a massive (~20-35 x 106 km2) hypothetical ice sheet. This massive ice sheet is traditionally interpreted to have covered much of southern Gondwana for >100 m.y. Meanwhile, recent studies of high-paleolatitude glacial deposits imply a much more complex pattern …


Anthropogenically Driven Changes To Shallow Groundwater In Southeastern Wisconsin And Its Effects On The Aquifer Microbial Communities, Madeline Jean Salo May 2019

Anthropogenically Driven Changes To Shallow Groundwater In Southeastern Wisconsin And Its Effects On The Aquifer Microbial Communities, Madeline Jean Salo

Theses and Dissertations

This study investigates if, and to what extent, the microbial community present in the shallow groundwater of southeastern Wisconsin is affected by the influx of treated municipal wastewater effluent. The primary study area consisted of three wells located in the shallow sand and gravel aquifer along the upper Fox River in Waukesha, Wisconsin. One well is located roughly 1500 feet from the river and pumps pristine groundwater. Two riverbank inducement wells are located within 200 feet of the river and pump a mixture of groundwater and river water that contains effluent from three upstream wastewater treatment plants. Water from all …


Incorporation, Morphology, And Extinction Of Framework-Building Metazoans In Early Cambrian Reef Ecosystems From The Western Usa And Mongolia And Their Effects On Reef Diversity, David Russell Cordie May 2019

Incorporation, Morphology, And Extinction Of Framework-Building Metazoans In Early Cambrian Reef Ecosystems From The Western Usa And Mongolia And Their Effects On Reef Diversity, David Russell Cordie

Theses and Dissertations

The early Cambrian represents an important transition in the evolution of life, perhaps most vividly exemplified by reef ecosystems as they changed from microbial-supported to metazoan-supported framework reefs. Microbial reefs were initially composed of Renalcis- and Epiphyton-group calcifying microbes. Subsequent reefs began to incorporate archaeocyathan sponges within this framework. This represents a shift in the source of carbonate production, which can be quantified using thin section point counts. In archaeocyathan reefs from the western USA, carbonate contribution from metazoan framework builders increased from zero to 29.7%. Similar reefs from Mongolia increased from zero to 5.0%. Increases in Laurentian archaeocyath contributions …


Anthropogenically Driven Changes To Shallow Groundwater In Southeastern Wisconsin And Its Effects On The Aquifer Microbial Communities, Madeline Jean Salo May 2019

Anthropogenically Driven Changes To Shallow Groundwater In Southeastern Wisconsin And Its Effects On The Aquifer Microbial Communities, Madeline Jean Salo

Theses and Dissertations

This study investigates if, and to what extent, the microbial community present in the shallow groundwater of southeastern Wisconsin is affected by the influx of treated municipal wastewater effluent. The primary study area consisted of three wells located in the shallow sand and gravel aquifer along the upper Fox River in Waukesha, Wisconsin. One well is located roughly 1500 feet from the river and pumps pristine groundwater. Two riverbank inducement wells are located within 200 feet of the river and pump a mixture of groundwater and river water that contains effluent from three upstream wastewater treatment plants. Water from all …


Analyzing Ductile Shear Zone Network Geometries In The Grassy Portage Sill, Rainy Lake Region, Northwestern Ontario, Canada, Ernest John Thalhamer Dec 2018

Analyzing Ductile Shear Zone Network Geometries In The Grassy Portage Sill, Rainy Lake Region, Northwestern Ontario, Canada, Ernest John Thalhamer

Theses and Dissertations

The Grassy Portage Sill (GPS) is a ~2.7 Ga metagabbroic sill located in the Rainy Lake region of northwestern Ontario. The Rainy Lake region is located in the Superior Province between the metavolcanic Wabigoon subprovince to the north and the metasedimentary Quetico subprovince to the south. Two regional faults bound the region and intersect to the east, forming a wedge which defines the Rainy Lake zone. This area was regionally deformed due to oblique transpression, resulting from the Kenoran Orogeny (~2.7 Ga). The GPS is approximately 20 km long and 1-2 km wide, and has undergone heterogeneous strain along its …


The Geochemistry And Mineralogy Of Surface Hydrothermal Alteration At Nesjavellir, Sw Iceland, Chase Glenister Aug 2018

The Geochemistry And Mineralogy Of Surface Hydrothermal Alteration At Nesjavellir, Sw Iceland, Chase Glenister

Theses and Dissertations

Abundant sulfates have been detected by the Mars Exploration Rover Spirit in the Columbia Hills of Mars, consistent with extensive alteration of basalt by hydrothermal processes. This study uses Iceland’s Nesjavellir geothermal system as an analogue for Columbia Hills hydrothermal alteration. This terrestrial site is home to a variety of acidic and near-neutral waters that are actively altering the Mars-like basalt of host volcano Mt. Hengill. Hydrothermal features heated by H2S gas and phase-segregated steam created oxidizing acid-sulfate conditions at the surface with pH values varying between 3.0 and 2.0 and near-boiling temperatures. Mobilization of cations (FeO, MgO, CaO, Na2O, …


Invertebrate Paleoecology Of High Paleo-Latitude Carboniferous Strata Of The Tepuel-Genoa Basin, Argentina, Kate M. Gigstad May 2018

Invertebrate Paleoecology Of High Paleo-Latitude Carboniferous Strata Of The Tepuel-Genoa Basin, Argentina, Kate M. Gigstad

Theses and Dissertations

The Late Paleozoic Ice Age (LPIA), which began in the latest Devonian and ended in the Late Permian, was a time of active environmental changes. During this time, glaciers waxed and waned over the ancient continent of Gondwana that was situated over the southern pole. This time of transition from icehouse to greenhouse in the Permian is our closest analogue to our current environmental conditions and increased knowledge of our planetary past will greatly influence our future. Much of the previous research on marine invertebrate paleoecology during the LPIA occurs in far-field or low paleolatitude localities, but less is known …