Geology Commons^™

Insight Into The Early Exhumation Of The Cycladic Blueschist Unit, Syros, Greece: Combined Application Of Zoned Garnet Geochronology, Thermodynamic Modeling, And Quartz Elastic Barometry, Jennifer S. Gorce, Mark J. Caddick, Ethan F. Baxter, Besim Dragovic, John C. Schumacher, Robert J. Bodnar, Jamie F. Kendall

Geology Faculty Publications and Presentations

Constraining conditions and mechanisms of the early stages of exhumation from within subduction zones is challenging. Although pressure, temperature, and age can be inferred from the exhumed rock record, it is generally difficult to derive each of these parameters from any single rock, thus demanding assumptions that diverse data from multiple samples can be safely combined into a single pressure-temperature-time (P-T-t) path that might then be used to infer tectonic context and mechanisms of exhumation. Here, we present new thermobarometric and geochronologic information preserved in a single sample from Syros, Greece, to deduce the …

Reconstructing 1856-7 California Mining Patterns From Placer Gold Recovered From The Wreck Of The Ss Central America, Kathryn Ruth Vonsydow

Electronic Theses, Projects, and Dissertations

The discovery of the SS Central America 1857 shipwreck site provides a time capsule that can be used to address questions about the spatial and temporal patterns of placer mining in California during the peak of the gold rush. Samples of placer gold in the collections of museums and private individuals can have uncertain pedigree due to labeling issues and alterations by cleaning and curatorial processes. However, placer gold from the 1857 shipwreck could only have come from the Mother Lode Country of California, as no other gold districts had yet been found in western North America. I compared the …

Spatial Analyses Of Gray Fossil Site Vertebrate Remains: Implications For Depositional Setting And Site Formation Processes, David Carney

Electronic Theses and Dissertations

This project uses exploratory 3D geospatial analyses to assess the taphonomy of the Gray Fossil Site (GFS). During the Pliocene, the GFS was a forested, inundated sinkhole that accumulated biological materials between 4.9-4.5 mya. This deposit contains fossils exhibiting different preservation modes: from low energy lacustrine settings to high energy colluvial deposits. All macro-paleontological materials have been mapped in situ using survey-grade instrumentation. Vertebrate skeletal material from the site is well-preserved, but the degree of skeletal articulation varies spatially within the deposit. This analysis uses geographic information systems (GIS) to analyze the distribution of mapped specimens at different spatial scales. …

Using An Inventory Of Unstable Slopes To Prioritize Probabilistic Rockfall Modeling And Acid Base Accounting In Great Smoky Mountains National Park, Thomas A. O'Shea

Electronic Theses and Dissertations

An inventory of unstable slopes along transportation corridors and performance modeling are important components of geotechnical asset management in Great Smoky Mountains National Park (GRSM). Hazards and risk were assessed for 285 unstable slopes along 151 miles of roadway. A multi-criteria model was created to select fourteen sites for two-dimensional probabilistic rockfall simulations and Acid Base Accounting (ABA) tests. Simulations indicate that rock material would likely enter the roadway at all fourteen sites. ABA test results indicate that influence of significant acid-producing potential is generally confined to slaty rocks of the Anakeesta Formation and graphitic schist of the Wehutty Formation. …

Analysis And Risk Estimation Of High Priority Unstable Rock Slopes In Great Smoky Mountains National Park, Tennessee And North Carolina, Samantha Farmer

Electronic Theses and Dissertations

Great Smoky Mountains National Park (GRSM) received 12.5 million visitors in 2020. With a high traffic volume, it is imperative roadways remain open and free from obstruction. Annual unanticipated rockfall events in GRSM often obstruct traffic flow. Using the Unstable Slope Management Program for Federal Land Management Agencies (USMP for FLMA) protocols, this study analyzes high priority unstable rock slopes through 1) creation of an unstable slope geodatabase and 2) generation of a final rockfall risk model using Co-Kriging from a preliminary risk model and susceptibility model. A secondary goal of this study is to provide risk estimation for the …

Sedimentology And Shallow Groundwater Responses Of A Coastal Marsh Along A Salinity Gradient: A Case Study In Grand Bay National Estuarine Research Reserve, Mississippi, James Thompson

Master's Theses

Climate change and relative sea level rise is resulting in saltwater intrusion and inundation of coastal marshes. This study investigates factors affecting marsh hydrology, including sediment composition, seasonal variability, and coastal storms in Grand Bay National Estuarine Research Reserve (NERR) near Pascagoula, Mississippi. Analysis of sediment includes color, organic matter, carbonate, magnetic susceptibility, and particle size. Shallow groundwater hydrologic trends between Summer 2015 and Fall 2016 are established along a salinity gradient at four sites using water levels, temperature, and conductivity monitored at the surface and in piezometers at depths of 0.75m, 1.5m, and 2.25m.

Sediment analysis indicates reducing conditions …

Constraining Deformation Mechanisms Of Fault Damage Zones: A Case Study Of The Shallow San Andreas Fault At Elizabeth Lake, Southern California., Caroline Studnicky

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Earthquakes nucleate at depth and rupture along the fault plane up to the Earth’s surface releasing seismic energy as the fault propagates. This energy creates the shaking we feel on the surface. Some faults do not rupture and create shaking but deform slowly and smoothly accommodating fault slip over extended time periods. This process is referred to as aseismic slip or creep. Whether a fault ruptures or creeps depends on the properties of the rocks through which the fault plane extends. In order to model seismic hazards correctly, we need to characterize the composition, deformation structures, and alteration materials of …

Geologic Characterization Of The Nonconformity Interface Using Outcrop And Drillcore Analogs: Implications For Injection-Induced Seismicity, Kayla Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Starting around 2009, a greater number of earthquakes than anticipated have occurred in the midcontinent region of the United States. These earthquakes have been linked to increased rates and volumes of wastewater injection at several km’s depth into the Earth’s crust near a contact between crystalline metamorphic or igneous rock and overlying sedimentary rock, known as a nonconformity. While much is known about why these new earthquakes occur, comparatively little is known about the physical and chemical rock properties because the nonconformity contact is primarily buried under km’s of sedimentary rock in the midcontinent region. These rock properties are important …

Mississippian Chat And Tripolite Zones In Osage County, Oklahoma: Paleokarst Interpretation Based On 3d Seismic And Well Logs, Olanrewaju Ayodapo Aboaba, Christopher Liner

Geosciences Faculty Publications and Presentations

Mississippian paleokarst chat and tripolitic chert (tripolite) zones associated with the Mississippian Lime have been hydrocarbon exploration targets in Osage County for many decades. Chat is residual chert, either in place or transported, weathered out of chert-bearing Mississippian Limestone that was eroded at the Mississippian-Pennsylvanian unconformity. Thus, the formation of chat is an epigene paleokarst process. Tripolite occurs as a highly porous, silica-rich interval within the Mississippi Lime. It is formed by in-place alteration of limestone by silica-rich surface waters or deep-seated hydrothermal fluids, making tripolite formation a mixed or hypogene paleokarst process. Here, we have studied chat and tripolite …

Exploring Questions Of Tectonic Geomorphology In The Bear River Range, Utah Using Terrain Analysis And Reconstruction, Edward M. Grasinger

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Despite a long tradition of geologic studies in the region surrounding Utah State University, there remain unexplored questions and unutilized approaches for understanding the landscape evolution of the Bear River Range. A large-scale reconstruction of the East Cache fault system can be useful in estimating the total displacement of the fault, its geologic longevity, and total energy involved. Likewise, an analysis of reach-scale features of the Logan River can explore how tectonics and bedrock type affect the patterns and history of the river. Geographic Information Systems (GIS) software is useful in reconstructing, visualizing, and measuring such geomorphological features and changes …

Novel Application Of 210po-210pb Disequilibria To Date Snow, Melt Pond, Ice Core, And Ice-Rafted Sediments In The Arctic Ocean, Mark Baskaran, Katherine Krupp, Mark Baskaran

Environmental Science and Geology Faculty Research Publications

We collected surface ocean water, snow, grab ice, ice core, melt pond and ice-rafted sediment (IRS) from 5 ice stations during the Western Arctic US GEOTRACES cruise (USGCG Healy; August 10 – October 7, 2015) and analyzed for 210Po (T1/2 = 138.4 days) and 210Pb (T1/2 = 22.3 years) in dissolved and particulate phases (snow, grab ice, ice core, surface seawater) to investigate the 210Po:210Pb disequilibria in these matrices. Thirteen aerosol samples, using a large-volume aerosol sampler (PM10), from Dutch Harbor, AK to North Pole, were also collected and analyzed for 210Po/210Pb to quantify the atmospheric depositional input to the …

Integrated Geophysical Analysis Over Bathymetrists Seamounts And The Sierra Leone Rise, Alexa Fernandez

UCARE: Research Products

The Bathymetrists Seamounts (BSM) are located northeast of the Sierra Leone Rise in the Atlantic Ocean. The northern seamounts have a southwest to northeast trend which is contrary to the current eastward motion of the African tectonic plate where they reside. The geological history and crustal structures of these features are poorly understood. The goal of this study is to integrate multiple geophysical data to better understand the crustal architecture and tectonic history of the BSM.

The seismic refraction study from Jones et al. (2015) was used as the baseline for isostatic modeling. This dataset suggested the presence of magmatic …

210po And 210pb As Tracers Of Particle Cycling And Export In The Western Arctic Ocean, Wokil Bam, Kanchan Maiti

Environmental Science and Geology Faculty Research Publications

The distribution and vertical fluxes of particulate organic carbon and other key elements in the Arctic Ocean are primarily governed by the spatial and seasonal changes in primary productivity, areal extent of ice cover, and lateral exchange between the shelves and interior basins. The Arctic Ocean has undergone rapid increase in primary productivity and drastic decrease in the areal extent of seasonal sea ice in the last two decades. These changes can greatly influence the biological pump as well as associated carbon export and key element fluxes. Here, we report the export of particulate organic and inorganic carbon, particulate nitrogen …

Developing A Database Of Seismic Data Over The Cascadia Subduction Zone, Khawlh Al Farsi

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

An inevitable megathrust earthquake is expected in the Cascadia subduction zone that will affect the population of the coast of southwestern British Columbia and the northwest of the United States. In this active tectonic margin, the Juan de Fuca oceanic plate is subducting beneath the North American continental plate, causing unevenly distributed seismic activity. The major goal of this geophysical research project is to study the tectonic structures of the Cascadia subduction zone in order to comprehend the geology of the region and investigate the seismic hazards. The primary objective of this project is to develop a geophysical database of …

40 Sets Of Strong Ground Motion Records Convey All Design Response Spectrums Located In Tartous, Syria, Dr. Seraj Jdyd

Journal of the Arab American University مجلة الجامعة العربية الامريكية للبحوث

Selecting seismic records in Global Standards is, until now, based on matching design response spectrum, where records should have seismological characteristics similar to the expected earthquake for the considered site (magnitude, distance, fault mechanism and soil conditions). Then it is necessary to scale these records to match the intensity of the earthquake expected for the site. Generally, scaling can be made by ground motions uniform scaling in time domain to best match (in average) the target spectrum within a period range of interest. Design ground motions are typically prescribed by smooth response spectra. But it is preferred to use a …

Single-Crystal Elasticity Of Tremolite At High-Pressure Conditions And Its Implication For The Mid-Lithospheric Discontinuity, Soisiri Charin

Earth and Planetary Sciences ETDs

Tremolite is the calcium magnesium amphibole that widely occurs in igneous and metamorphic rocks of the crustal and upper mantle lithosphere, especially in the greenschist facies to amphibolite facies of ultramafic assemblages. The stability field of amphibole reaches 3-4 GPa and 1100-1200°C depending on water content and cation substitutions giving rise to amphibole to occur in highly variable compositions. This P-T condition, corresponding to the depth about 80-120 km, coincides with the depth range that a negative velocity gradient usually found within most stable cratonic lithospheres. This depth range is seismically called Mid-lithosphere discontinuity (MLD). The geologic processes that might …

Rezina Shams – The First Known Woman Geologist From Dhaka University (Bangladesh) To Obtain A Phd, Nazrul I. Khandaker

Publications and Research

Rezina Shams (Dhaka University geology graduate 1985; née Rezina Bashar) is the first known female geologist from Bangladesh to obtain a PhD in 1991 (University of Birmingham, UK). Rezina’s undergraduate and graduate education in geology at Dhaka University (DU) was at a time when only a handful of female students attended the program. Rezina’s debut into her geology career began with the Master Plan Organisation (MPO) and then the Bangladesh Atomic Energy Commission (1986). Rezina kept her aspirations alive, and eventually furthered her geoscience education to a PhD. Upon receiving a PhD in 1991 from the University of Birmingham under …

Causes And Characteristics Of Electrical Resistivity Variability In Shallow (<4 M) Soils In Taylor Valley, East Antarctica, William S. Gutterman

LSU Master's Theses

The McMurdo Dry Valleys are the largest ice-free region in Antarctica and are characterized as a polar desert environment. Soils in the region are typically very dry (<1% soil water by weight) and remain frozen for most of the year. Increases in air temperature and incoming solar radiation during the austral summer generate meltwater from glaciers, ground ice, and snow patches supplying moisture to soils and altering the physical and chemical makeup of the subsurface. Previous studies have utilized airborne electromagnetic surveys (AEM) to analyze groundwater systems in the deep subsurface but have not yet examined soil moisture in the shallow (<4 m) subsurface. Here, I used electrical resistivity data from two AEM surveys (2011 and 2018) and soil geochemical data from three transects to characterize the spatial heterogeneity of soil properties in the near-subsurface of lower Taylor Valley. Soil resistivities from 2011 and 2018 range from 33.2 Ωm to 3535 Ωm with low elevations of <100 meters above sea level (masl) typically displaying the lowest resistivities and high elevations displaying greater resistivities. Liquid brine fractions were empirically estimated from electrical resistivity values using Archie’s Law and range from 0.3% to 68.2% for soils with resistivities <200 Ωm. Additionally, soil transect data show greater percentages of fine-grained sediments (<63 µm) exist at elevations <100 masl where soil resistivities begin decreasing. Resistivity variability in the subsurface is ultimately controlled by the site history, local and regional climate, soil salinity, soil moisture, soil lithology.

Mgrre_Thinsections_Mgrre_13_40, Mgrre

Thin Sections

No abstract provided.

Ice-Crystal Traces Imply Ephemeral Freezing In Early Permian Equatorial Pangea, Lily S. Pfeifer, Brooke A. Birkett, Jean Van Den Driessche, Stephane Pochat, Geriliyn S. Soreghan

School of Earth & Environment Departmental Research

Delicate impressions in lacustrine strata of the lower Permian (lower Cisuralian) Usclas Formation record ephemeral freezing in equatorial Pangea. These sediments accumulated in the paleoequatorial and intramontane Lodève Basin (southern Massif Central, France) during peak icehouse conditions of the Late Paleozoic Ice Age. Experimental replication of these features supports the interpretation that they are ice-crystal molds. Evidence for films of ice in marginal-lacustrine sediment at such low latitudes and inferred low to moderate altitudes (1–2 km) calls for a reevaluation of climate conditions in eastern equatorial Pangea. Ephemeral freezing implies either cold tropical temperatures (~5 °C cooler than the Last …