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Full-Text Articles in Physical Sciences and Mathematics

Integrating Lidar, Aeromagnetic, And Geological Field Data To Identify Structural-Lithologic Elements Within The Archean Carney Lake Gneiss Complex, Ian M. Gannon Jan 2023

Integrating Lidar, Aeromagnetic, And Geological Field Data To Identify Structural-Lithologic Elements Within The Archean Carney Lake Gneiss Complex, Ian M. Gannon

Dissertations, Master's Theses and Master's Reports

The Archean Carney Lake Gneiss Complex (CLGC) is a suite of rocks on the southern margin of the Superior Province and within the Minnesota River Valley subprovince. It is one of many gneissic domes in Michigan, Wisconsin, and Minnesota whose complex geology is poorly understood due to a previous lack of economic interest in gneissic terranes and significant challenges to their investigation. As a consequence, the CLGC and other gneissic domes in the region are represented on geologic maps as undifferentiated masses surrounded by better defined and understood Paleoproterozoic supracrustal rocks and igneous intrusions. Within the last ten years, however, …


Structural Analysis And Interpretation Of Deformation Along The Keweenaw Fault System From Lake Linden To Mohawk, Michigan, Nolan G. Gamet Jan 2023

Structural Analysis And Interpretation Of Deformation Along The Keweenaw Fault System From Lake Linden To Mohawk, Michigan, Nolan G. Gamet

Dissertations, Master's Theses and Master's Reports

The Keweenaw fault is likely the most significant and most studied fault associated with the Midcontinent Rift System. The fault roughly bisects the Keweenaw Peninsula and places Portage Lake Volcanics (~1.1 Ga) over much younger Jacobsville Sandstone (~1.0 Ga). Published bedrock geology maps with cross sections from the 1950s show the fault as a single continuous trace that is locally associated with smaller cross faults and splays. The accompanying cross-sections show hanging-wall volcanic strata having a well-defined, listric geometry with dip decreasing away from the fault to the northwest.

This M.S. thesis presents a structural analysis and interpretation of the …


Climate Changes In El Salvador: Impacts Of ‘La Canícula’ (Midsummer Drought) On Agricultural Practices And Decision-Making In Rural Communities, Paola M. Rivera González Jan 2023

Climate Changes In El Salvador: Impacts Of ‘La Canícula’ (Midsummer Drought) On Agricultural Practices And Decision-Making In Rural Communities, Paola M. Rivera González

Dissertations, Master's Theses and Master's Reports

The Central American Dry Corridor (CADC), a tropical, dry-forest region, is characterized by distinct rainy and dry seasons, which influence the local agricultural calendar and planting decisions in rural communities. La canícula is a period of decreased precipitation during the rainy season, which occurs during the corn-planting season in El Salvador. La canícula is expected to change in intensity and duration in the next decades, which would impact small-scale farmers and their livelihoods. Climate variability and uncertainty has led to crop loss, water scarcity, and food insecurity in rural communities dependent on subsistence farming. Farmers’ experiences with a changing climate …


Age And Chemistry Of Bell Creek Batholith, Elana G. Barth Jan 2023

Age And Chemistry Of Bell Creek Batholith, Elana G. Barth

Dissertations, Master's Theses and Master's Reports

The Southern Complex, located near Marquette, Michigan is in the southernmost portion of the Superior Province. This complex consists of granitoids and granitic gneiss that vary in composition. In twentieth century research, Hoffman (1987) and Tinkham (1997) concluded that the Southern Complex contained two units in which the granitoid was emplaced in the granitic gneiss. Recent research conducted by Petryk (2019) determined that the Southern Complex has a U-Pb zircon age of 2600 Ma. Dalle Fratte (2020) concluded that the granitic gneiss migmatite texture was the result of a felsic magma mixing with several generations of mafic intrusions that were …


Structural Analysis And Slip Kinematics Of The Keweenaw Fault System Between Bête Grise Bay And Gratiot Lake, Keweenaw County, Michigan, Daniel J. Lizzadro-Mcpherson Jan 2023

Structural Analysis And Slip Kinematics Of The Keweenaw Fault System Between Bête Grise Bay And Gratiot Lake, Keweenaw County, Michigan, Daniel J. Lizzadro-Mcpherson

Dissertations, Master's Theses and Master's Reports

The Keweenaw fault is perhaps the most significant geologic structure on the Keweenaw Peninsula, with an estimated 7-11 km of reverse slip juxtaposing volcanic strata of the ~1.1 Ga Portage Lake Volcanics above ~1.0 Ga Jacobsville Sandstone. The fault has been interpreted as a rift-bounding normal fault later inverted by compressional pulses of the Grenville Orogeny or, more recently, as part of a detached thrust fault system unrelated to an earlier normal fault. The fault is shown on published maps as a single continuous fault trace whose sinuosity implies multiple fault segments and complex slip dynamics. Mapping along Bête Grise …


Rain-Induced Hazards In Remote, Low-Resource Communities: A Case Study Of Flash Flooding In The Usulután Department, El Salvador, Natalea Cohen Jan 2023

Rain-Induced Hazards In Remote, Low-Resource Communities: A Case Study Of Flash Flooding In The Usulután Department, El Salvador, Natalea Cohen

Dissertations, Master's Theses and Master's Reports

Rain-induced natural hazards can lead to devastating and potentially life-threatening impacts. Understanding areas susceptible to flash flooding and characterizing the intensity of flash flood events is critical in improving the mitigation and emergency preparedness of vulnerable communities. Flash floods occur on small spatial scales and for short durations making it challenging to classify flash flood susceptibility and forecast events. Modeling flash flooding becomes even more difficult when focusing on data-poor regions. This study is based in California, El Salvador, an agricultural community located in the Central American Dry Corridor (CADC), a region experiencing the impacts of climate change and associated …


Thermomechanical Evolution Of A Magmatic System During A Caldera Cycle: Okataina Volcanic Center, New Zealand, Jacob Bonessi Jan 2022

Thermomechanical Evolution Of A Magmatic System During A Caldera Cycle: Okataina Volcanic Center, New Zealand, Jacob Bonessi

Dissertations, Master's Theses and Master's Reports

Caldera forming eruptions represent some of the largest simultaneous releases of mass and energy on the planet and pose a looming risk on a global scale. The study of the underlying magmatic systems is integral in understanding what leads to these large eruptions. This approach pairs a suite of major and trace element profiles from plagioclase with a grain texture classification and statistical analysis using Polytopic Vector Analysis (PVA) as proxies to explore potential changes in the thermomechanical state of the magmatic system at Okataina Volcanic Complex (OVC), New Zealand through its most recent caldera cycle. Results indicate systematic changes …


Defining The Endmember System Of Us Soils And Quantifying Relationships, And A Hyperspectral Approach To The Alteration Strength Index, Rachel Rulison Jan 2022

Defining The Endmember System Of Us Soils And Quantifying Relationships, And A Hyperspectral Approach To The Alteration Strength Index, Rachel Rulison

Dissertations, Master's Theses and Master's Reports

Soils form a complex part of the environment, providing important functions in systems such as food production, groundwater movement, and ecosystem health. There have been numerous studies on soil geochemistry and the origin of elements within soils, but few studies into quantifying the relationships between elements and geographical data on a national scale. Using geochemical data obtained by the USGS, the surficial soils of the US were defined by a 13-endmember system using Polytopic Vector Analysis and mapped in GIS. Correlation matrices provided Pearson’s correlation coefficients for elements in the Top 5 cm soil profile, the A horizon, and the …


Building Interest And Knowledge In Geosciences Through Place- & Field-Based Teacher Professional Learning Programs: A Comparative Multi-Case Study, Emily Gochis Jan 2022

Building Interest And Knowledge In Geosciences Through Place- & Field-Based Teacher Professional Learning Programs: A Comparative Multi-Case Study, Emily Gochis

Dissertations, Master's Theses and Master's Reports

The focus of this study was to develop and evaluate a geoscience professional development model that would improve K-12 teachers’ capacity to effectively build geoscience literacy and interests in students from a variety of settings and cultural groups. The research compared the application of a geoscience professional development model realized through multiple case studies of varying settings and scales. The study investigated the capacity of each approach in improving teachers’ geoscience background knowledge, awareness of local geologically and culturally significant examples, and ability to integrate place-based, field investigations into standards-based curricula. By using both qualitative and quantitative methodologies, the study …


A Global Survey Of Volcanic So2 Emissions And Heat Flux Measured From Space, Nelmary Rodríguez-Sepúlveda Jan 2022

A Global Survey Of Volcanic So2 Emissions And Heat Flux Measured From Space, Nelmary Rodríguez-Sepúlveda

Dissertations, Master's Theses and Master's Reports

Over the past two decades, the availability of satellite measurements of volcanic gas emissions and heat flux has driven the development of new methodologies to improve global-scale volcano monitoring. In this work we explored the relationship between volcanic sulfur dioxide (SO2) emissions and radiant heat flux (RHF) measurements from NASA’s Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS), respectively, to gain insight into how it associates to volcanic processes and eruption styles. The OMI SO2 emissions data are derived from existing databases developed by using the methodology in Fioletov et al. (2016), which contain global, …


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 …


Volcan De Fuego: A Machine Learning Approach In Understanding The Eruptive Cycles Using Precursory Tilt Signals, Kay Sivaraj Jan 2021

Volcan De Fuego: A Machine Learning Approach In Understanding The Eruptive Cycles Using Precursory Tilt Signals, Kay Sivaraj

Dissertations, Master's Theses and Master's Reports

Volcan de Fuego is an active stratovolcano located in the Central Guatemalan segment of the 1100 m long Central America Volcanic Arc System (CAVAS). Fuego-Acatenango massif consists of at least four major vents of which the Fuego summit vent is the most active and the youngest member. The volcano exhibits primarily Strombolian and Vulcanian behavior along with occasional paroxysms and pyroclastic flows. Historically, Fuego has produced basaltic-andesitic rocks with more recent eruptions progressively trending towards maficity. Several studies have used short-term deployments of broadband seismometers, infrasound, and long-term remote sensing techniques to characterize the mechanism of Fuego. In our study, …


Structural Analysis And Interpretation Of Deformation Along The Keweenaw Fault System West Of Lake Gratiot, Keweenaw County, Michigan, Sophie A. Mueller Jan 2021

Structural Analysis And Interpretation Of Deformation Along The Keweenaw Fault System West Of Lake Gratiot, Keweenaw County, Michigan, Sophie A. Mueller

Dissertations, Master's Theses and Master's Reports

The Keweenaw fault is perhaps the most significant fault associated with the Midcontinent Rift System of the north-central United States. The fault, parallel to the south edge of the rift, has been interpreted as a rift-bounding normal fault that was inverted by subsequent compressional events, thrusting copper-bearing Portage Lake Volcanics (~ 1.1 Ga) over younger Jacobsville Sandstone. Geologic maps and cross sections published in the 1950s by the U. S. Geological Survey depict the fault with a well-defined, single, sinuous trace that is locally associated with smaller branch faults. Cross-sections from that time generally show a simple listric stratal geometry …


Comparing Scoop3d And Gis-Tissa Models For Slope Stability Analysis In Idukki, Kerala, India, Stepan Pikul Jan 2021

Comparing Scoop3d And Gis-Tissa Models For Slope Stability Analysis In Idukki, Kerala, India, Stepan Pikul

Dissertations, Master's Theses and Master's Reports

Landslides are the most destructive hazard in the mountainous Idukki district in the State of Kerala, India. Therefore, evaluating the possible occurrence of landslides and analyzing the factors that trigger failure is an essential part of a reliable landslide assessment. Physics-based models are commonly used to determine potential landslide susceptible areas in terms of Factor of Safety (FS). Recent years have seen the use of physics-based methods for regional-scale landslide susceptibility analysis using geospatial tools. In this study, we compare two physics-based models using the same data from Idukki. The two models are the Geographic Information System-Tool for Infinite Slope …


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 …


Utilization Of Paenibacillus Polymyxa In The Recovery Of Lithium Bearing Minerals, Diana Bullen Jan 2021

Utilization Of Paenibacillus Polymyxa In The Recovery Of Lithium Bearing Minerals, Diana Bullen

Dissertations, Master's Theses and Master's Reports

In the global transition to green energy in the transportation and power production sectors, lithium has emerged as a viable solution, and crucial component, for the effective storage of renewable resources. To avoid further degradation of the land due to mining for virgin material, methods focused on recovering lithium must be developed. This research project seeks to explore a new way to recover lithium by using the bacterium Paenibacillus polymyxa. The bacteria were grown and then applied to the lithium bearing mineral spodumene. Settling velocity profiles were constructed for different treatments of spodumene. It was found that the spodumene …


Mapping Michigan's Historic Coastlines, Ryan A. Williams Jan 2021

Mapping Michigan's Historic Coastlines, Ryan A. Williams

Dissertations, Master's Theses and Master's Reports

This five-year project, sponsored by the Michigan Department of Environment, Great Lakes, and Energy, is working to map how Michigan’s Great Lakes shorelines have changed over the past 80+ years. Products of this project include publicly available digital, georeferenced, historic aerial photography datasets, as well as map layers depicting the locations of historic shorelines and bluff lines from 1938, 1980, 2009, 2016, 2018, and 2020. Additional products include bluff retreat risk areas, shoreline rate of change map layers, and tools to assist in the development of future Coastal Vulnerability Index projects for the Great Lakes. All products are available as …


Joint Simulation Of Continuous And Categorical Variables For Mineral Resource Modeling And Recoverable Reserves Calculation, Sentle Augustinus Hlajoane Jan 2020

Joint Simulation Of Continuous And Categorical Variables For Mineral Resource Modeling And Recoverable Reserves Calculation, Sentle Augustinus Hlajoane

Dissertations, Master's Theses and Master's Reports

Spatial variability and uncertainty of continuous variables (grade) and categorical variables (rock-types) in mineral evaluation significantly impact the economics of mining projects. The conventional approach of simulating grades using deterministic rock- types is problematic since spatial variability, and uncertainty of grades at rock-type contacts are not well captured in deposits where the grade changes gradually between rock-types. Therefore, jointly simulating these variables can improve confidence (reduce uncertainty) in a resource model. Also, resource classification and recoverable reserve calculation can significantly improve the understanding of the deposit and its economic viability. This research utilized the Plural-Gaussian geostatistical simulation to jointly simulate …


A Multi-Year Analysis From 2014 To 2017 Of Snowfall Types In Marquette, Michigan: A Differentiation Between Synoptic Snow Events And Lake Effect Snow Events Impacted By The Presence Of Lake Superior, Roberto Piemontese Jan 2020

A Multi-Year Analysis From 2014 To 2017 Of Snowfall Types In Marquette, Michigan: A Differentiation Between Synoptic Snow Events And Lake Effect Snow Events Impacted By The Presence Of Lake Superior, Roberto Piemontese

Dissertations, Master's Theses and Master's Reports

The present study analyzes four winter seasons of data from 2014 to 2017 collected from the National Weather Service in Marquette, Michigan. The two main instruments installed are the MRR, which provides a vertical reflectivity profile from ground level to 3 km, and the PIP, a horizontal camera pointing towards a light source, which measures the physical characteristics of each particle. The observations show that LES events are shallow, with heights of up to 1500 m, meanwhile synoptic events are deep, with vertical profile of 3000 m or beyond. The shallow events have bigger and low-density particles and synoptic events …


Reconstruction Of The 2018 Anak Krakatau Collapse Using Planetscope Imaging And Numerical Modeling, Davide Saviano Jan 2020

Reconstruction Of The 2018 Anak Krakatau Collapse Using Planetscope Imaging And Numerical Modeling, Davide Saviano

Dissertations, Master's Theses and Master's Reports

The study was focused on the Anak Krakatau sector collapse that occurred on 22 December 2018 in the Sunda Strait (Indonesia). The goal of the study was to monitor and analyze changes of the volcanic edifice and to try to understand causes that may have predisposed and triggered the sector collapse.

The use of different remote sensing techniques allowed the acquisition of thermal data, SO2 emission data, structural data and the identification and analysis of the eruptive events that occurred on Anak Krakatau in the period from 1° January 2016 to 28 February 2019. The acquisition of 1221 thermal …


Fluid Inclusion Study Of Selected Calcite Associated With Native Copper, Quincy Mine, Keweenaw Peninsula, Michigan, David Kelly Jan 2020

Fluid Inclusion Study Of Selected Calcite Associated With Native Copper, Quincy Mine, Keweenaw Peninsula, Michigan, David Kelly

Dissertations, Master's Theses and Master's Reports

The Keweenaw Peninsula is famous for hosting the largest accumulation of native copper anywhere in the world. Previous studies have looked for the fluids responsible for creating the native copper deposits but were unable to conclusively demonstrate that fluid inclusions can provide valuable insight into the hydrothermal/metamorphogenic fluids responsible for these unique deposits.

This report focused on fluid inclusions from calcite precipitated during the native copper mineralizing event. Calcite crystals with inclusions of native copper growing into vugs from a single location, the Quincy Mine, were hypothesized to have a higher chance to be undisturbed by seismic events that would …


The Impacts Of Accessibility On Vulnerability Of Place In Comfort Castle, Jamaica, Heather Thole Jan 2020

The Impacts Of Accessibility On Vulnerability Of Place In Comfort Castle, Jamaica, Heather Thole

Dissertations, Master's Theses and Master's Reports

Jamaica experiences meteorological, hydrological, and geological natural hazards that can produce island-wide impacts. The island’s exposure to multiple hazard types requires effective and sustainable mitigation and disaster risk management to lessen potential impacts, especially for vulnerable populations and communities. Comfort Castle, a small rural farming community, sits in the upper Rio Grande Valley of Portland parish and experiences earthquakes, landslides, hurricanes, heavy rainfall, and floods. Steep terrain and remoteness due to geographic location affect the community’s geophysical vulnerability. Their social vulnerability results from a lack of employment, health, educational, and livelihood resources within the community. Together, geophysical, and social factors …


Assessing The Accuracy Of A Uav Snow Depth Survey: Utqiagvik (Barrow), Alaska Calm Grid, Ian Nichols Jan 2020

Assessing The Accuracy Of A Uav Snow Depth Survey: Utqiagvik (Barrow), Alaska Calm Grid, Ian Nichols

Dissertations, Master's Theses and Master's Reports

Active layer depth and snow depth are annually collected across the Circumpolar Active Layer Monitoring (CALM) Network to observe the response of the active layer and near-surface permafrost to climate change over decadal-time scales. Snow depth is typically measured using a graduated steel probe at each grid node but, in this paper, we explore the viability of using Unmanned Aerial Vehicle (UAV) (drone) technology to collect snow depth measurements at the 1 km2 Utqiagvik (Barrow), Alaska CALM grid. This is achieved by comparing estimated UAV snow depths to measured snow depths collected using a MagnaProbe (MP) at each of …


Rain Generated Lahars Prior To The 2018 Catastrophic Eruption Of Fuego Volcano, Guatemala, Claudia Buondonno Jan 2020

Rain Generated Lahars Prior To The 2018 Catastrophic Eruption Of Fuego Volcano, Guatemala, Claudia Buondonno

Dissertations, Master's Theses and Master's Reports

Fuego volcano is one of the most active and hazardous volcanoes in the world. It is located in the northern part of the Central American Volcanic Arc in Guatemala and its activity can be characterized by long term, low-level background activity, and sporadic larger explosive eruptions. Its historical observations of eruptions date back to 1531, but it has been erupting vigorously since 2002 with major activity throughout 2018, producing three main eruptions in February, June and November. Its almost persistent activity generates major ashfalls, pyroclastic flows, lava flows; when heavy rains mobilize its deposits, they can form damaging lahars. Phenomena, …


Quantifying Water Recharge And Water Use In Hand Dug Wells: A Case Study Of Thiawor, Senegal, West Africa, Celine Carus Jan 2020

Quantifying Water Recharge And Water Use In Hand Dug Wells: A Case Study Of Thiawor, Senegal, West Africa, Celine Carus

Dissertations, Master's Theses and Master's Reports

For many rural communities in Senegal, water is an essential life-giving need received only through a network of hand dug wells. Increasing rainfall variability in the Sahel has driven greater water insecurity for those communities that rely on rain-irrigated systems for agriculture. This study investigates the retrieval, purposes, and quantities of seasonal water usage on a small domestic scale, as well as an analysis of perceived water availability in the wells during the rainy season. Additionally, using a combination of interview data and pumping test data obtained from the village wells, water usage and estimated daily needs are calculated and …


The Effect Of Spacing Of Vetiver Grass (Chrysopogon Zizanioides) Hedgerows On Hillslope Erosion In Eastern Region, Ghana, Evan R. Lanese Jan 2020

The Effect Of Spacing Of Vetiver Grass (Chrysopogon Zizanioides) Hedgerows On Hillslope Erosion In Eastern Region, Ghana, Evan R. Lanese

Dissertations, Master's Theses and Master's Reports

Soil erosion in Ghana negatively effects many small holder farmers due to heavy rainfall, continuous land use, and a changing climate. Inexpensive, local, and sustainable practices that can be used to reduce soil movement thus building productive soils would benefit farmers in Ghana. Vetiver grass (Chrysopogon zizanioides) has been used to this effect worldwide. Its local availability and positive reputation leaves desire to learn about its applicability in Ghana. A field study was conducted on plots of sloping farmland (10ft by 60ft) with three treatments: (1) control with no vetiver grass, (2) two vetiver grass hedgerows, (3) four …


Application Of A Distributed Hydrologic Model For The Analysis Of Land Use Change In Kedougou, Senegal, Francisco Perez Jan 2019

Application Of A Distributed Hydrologic Model For The Analysis Of Land Use Change In Kedougou, Senegal, Francisco Perez

Dissertations, Master's Theses and Master's Reports

West Africa has experienced extensive land use/land cover (LULC) change since the Sahel drought of the 1970s and 80s. Demographic changes, rapid urbanization, and other anthropogenic impacts on land cover in West Africa have potentially altered hydrological regimes. This work was undertaken while I served as a Peace Corps Volunteer in the Kedougou region of Senegal, an area that has experienced significant and rapid infrastructural improvements and urbanization since the early 2000s. The Gambia River flows near Kedougou, where flooding is an extensive problem, making access and livelihood practices difficult during the rainy season. Changes in climate and land use …


Keweenaw Fault Geometry And Slip Kinematics - Bête Grise Bay, Keweenaw Peninsula, Michigan, Colin Tyrrell Jan 2019

Keweenaw Fault Geometry And Slip Kinematics - Bête Grise Bay, Keweenaw Peninsula, Michigan, Colin Tyrrell

Dissertations, Master's Theses and Master's Reports

The Keweenaw Fault (KF) has been interpreted as a rift-bounding normal fault along the southern margin of the Midcontinent Rift System; later inverted into a reverse fault by a tectonic compression event. The fault trends NNE to NE for most of its trace but curves clockwise to ESE along the Bête Grise Bay area in Michigan’s Keweenaw Peninsula. U.S. Geological Survey maps depict the KF along Bête Grise Bay as a continuous thrust that follows a sinuous contact between Portage Lake Volcanics (PLV) and Jacobsville Sandstone (JS). New fieldwork reveals a left-stepping en echelon system of ESE-trending faults connected by …


The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk Jan 2019

The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk

Dissertations, Master's Theses and Master's Reports

The Southern Complex is part of the Archean Superior Province in the Upper Peninsula of Michigan and includes a batholithic sized body of Archean high-K megacrystic granitoid rocks informally called the Bell Creek granite. U-Pb zircon ages of the granitoid from previous studies suggest an emplacement age of ~2.6 Ga (Tinkham, 1997). Based on those ages the Bell Creek granite formed around the Archean-Proterozoic transition. This transition is a crucial time period in Earth’s history for crustal growth because of the onset of subduction and increased sedimentary environments at the end of the Archean (Taylor and McLennan, 1995). In this …


Paleomagnetic Investigation Of Igneous Rocks Deformed By The Keweenaw Fault In The Northwestern Keweenaw Peninsula., Daniel Trekas Jan 2019

Paleomagnetic Investigation Of Igneous Rocks Deformed By The Keweenaw Fault In The Northwestern Keweenaw Peninsula., Daniel Trekas

Dissertations, Master's Theses and Master's Reports

One of the most prominent structural features associated with the ~1.1 Ga Midcontinent Rift (MCR) system is the >350 km long Keweenaw Fault that bisects the Keweenaw Peninsula, separating the MCR-related Portage Lake Volcanics (PLV) and the younger Jacobsville Sandstone (JS). The fault trend is NE-NNE over most of its length, but changes to an easterly direction along the shore of Bête Grise Bay near the end of the peninsula. Conventionally, the Keweenaw Fault has been considered to be a continuous reverse (dip-slip) fault formed by inversion of an original rift-bounding normal fault during the Grenville Orogeny. However, recent mapping …