Geology Commons^™

Thermotectonic History Of The Kluane Ranges And Evolution Of The Eastern Denali Fault Zone In Southwestern Yukon, Canada, Robert G. Mcdermott, Alexis K. Ault, Jonathan Saul Caine, Stuart N. Thomson

Geosciences Faculty Publications

Exhumation and landscape evolution along strike‐slip fault systems reflect tectonic processes that accommodate and partition deformation in orogenic settings. We present 17 new apatite (U‐Th)/He (He), zircon He, apatite fission‐track (FT), and zircon FT dates from the eastern Denali fault zone (EDFZ) that bounds the Kluane Ranges in Yukon, Canada. The dates elucidate patterns of deformation along the EDFZ. Mean apatite He, apatite FT, zircon He, and zircon FT sample dates range within ~26–4, ~110–12, ~94–28, and ~137–83 Ma, respectively. A new zircon U‐Pb date of 113.9 ± 1.7 Ma (2σ) complements existing geochronology and aids in interpretation …

Identifying Characteristics Of Actionable Science For Drought Planning And Adaptation, Adam Wilke, Amanda Cravens

United States Geological Survey: Publications

Changing climate conditions can make water management planning and drought preparedness decisions more complicated than ever before. Federal and State natural resource managers can no longer rely solely on historical trends as a baseline and thus are in need of science that is relevant to their specific needs to inform important planning decisions. Questions remain, however, regarding the most effective and efficient methods for extending scientific knowledge and products into management and decision-making. This project analyzed two unique cases of water management to better understand how science can be translated into resource management actions and decision-making, focusing particularly on how …

Regional Modeling Of The Glaciers Of The North Cascades Mountains, Washington, Usa, Christina Eileen Gray

Dissertations and Theses

Glaciers in the North Cascades store winter snowfall as ice and release it in late summer as melt, providing an important regional source of water and hydroelectric energy. The future of glaciers in the North Cascades, Washington, were evaluated using a regional glaciation model driven by the Community Climate System Model 4 global climate model. The climate model was coupled with three Representative Concentration Pathways (RCPs), 2.6, 4.5, and 8.5. These RCPs provide a business-as-usual scenario (RCP 8.5), which assumes society makes little to no efforts to reduce greenhouse gas emissions, a best-case scenario (RCP 2.6) with strong attempts to …

Early Mississippian Ocean Anoxia Triggering Organic Carbon Burial And Enhancing Late Paleozoic Ice Age Onset: Evidence From Uranium Isotopes Of Marine Limestones, Keyi Cheng

Earth and Planetary Sciences ETDs

The Early Mississippian (Tournaisian) positive δ¹³C excursion (or TICE) is one of the largest recorded in the Phanerozoic and the organic carbon (OC) burial associated with its development is hypothesized to have driven global cooling and increased glaciation. We are testing the hypothesis that expanded ocean euxinia/anoxia drove widespread OC burial and the TICE and we are testing this hypothesis using uranium isotopes (δ²³⁸U) of Lower Mississippian marine limestones from southern Nevada as a global seawater redox proxy.

δ²³⁸U trends record a prominent mid-Tournaisian negative excursion (~0.30‰ magnitude) lasting ~1 My. The lack of …

Collaborative Research: Tespresso, Tectonic Encoding, Shredding, And Propagation Of Environmental Signals As Surficial Observables, Tammy M. Rittenour

Funded Research Records

No abstract provided.

Breakdown Mechanisms In Iron Caves. An Example From Brazil, Marcelo R. Barbosa, Allan D.F. Da Silva, Rafael G. De Paula, Georgete M. Dutra, Airton Barata, Iuri V. Brandi, Chrystophe R.P. Da Silva, Robert A. Osborne

International Journal of Speleology

An iron cave in the vicinity of a mine in Carajás, Brazil, was selected to be mined within an assisted elimination project, planned to control all mine advancement operations towards the cave along with a strict speleological physical monitoring. It allowed, in a pioneering way, the recording of events in the cave from the first signs of damage until to the total collapse of the cave. The project lasted four years and it was possible to identify and describe four breakdown mechanisms in iron caves: Fragment downfall, Block downfall, Controlling structure reactivation, and Open discontinuity movement. The mechanisms occurred independently …

Stable Isotope Geochemistry Of Shelled Marine Invertebrates: Wide-Ranging Applications, Nasser M. Al-Qattan

USF Tampa Graduate Theses and Dissertations

Mollusks grow by adding discrete growth layers throughout their lifetime (i.e., accretion). More specifically, most marine mollusks precipitate their shells in oxygen isotopic equilibrium with seawater or with a constant offset from equilibrium. The stable oxygen isotope values (δ¹⁸O) of their shells are determined by the temperature and δ¹⁸O values of the surrounding water during calcification without significant vital effects. In comparison, the stable carbon isotope values (δ¹³C) of their shells reflect those of the dissolved inorganic carbon (δ¹³C- DIC) and respired carbon dioxide. Therefore, variations in the oxygen and carbon isotope …

Gage County Preliminary Ground Water Study (Gm-20): Reed, E.C. Conservation And Survey Division , Size 8.5" X 11"., E.C. Reed

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Modeling And Assessing Lava Flow Hazards, Elisabeth Gallant

USF Tampa Graduate Theses and Dissertations

Lava flow hazards are one of the few constant themes across the wide spectrum of volcanic research in the solar system. These dynamic hazards are controlled by the location of the eruption, the topography and material properties of the land upon which the flow spreads, and the properties of the lava (e.g., volume, temperature, and rheology). Understanding the influences on eruption location and how lava flows modify the landscape are important steps to accurately forecast volcanic hazards. Three studies are presented in this dissertation that address di˙erent aspects of modeling and assessing vent opening and lava flow hazards.

The first …

Framing Geologic Numeracy For The Purpose Of Geoscience Education: The Geoscience Quantitative Preparation Survey, Victor J. Ricchezza

USF Tampa Graduate Theses and Dissertations

The Geoscience Quantitative Preparation Survey (GQPS) was developed to address a deficiency in the available literature regarding the competency and preparation of early-career geologists in geoscience job-related quantitative skills – namely, geologic numeracy. The final version of the GQPS included self-confidence, usage, satisfaction, and demographic sections. The GQPS was expected to produce data that would allow for an evaluation of the geologic numeracy of early-career geologists and the success of approximately 20 years of increased focus on quantitatively literate geoscience graduates.

The self-confidence section of the GQPS included quantitative methods and quantitative skills. The usage section asked whether participants used …

Lithological Character And Sequence Stratigraphy Of The Ste. Genevieve Limestone In Western Kentucky, Zachary Dalton Creech

Masters Theses & Specialist Projects

The Ste. Genevieve Limestone is a Mississippian-aged, carbonate-dominated stratigraphic unit that is a prominent hydrocarbon producer in the Illinois Basin, and is widely distributed in states such as Missouri, Kentucky, Indiana, and Illinois. There has been relatively limited study focused on characterizing the Ste. Genevieve Limestone in terms of lithofacies, stacking patterns, and sequence stratigraphic context via analysis of roadcut exposures of the unit in western Kentucky.

The focus of this study is to use lithologic data collected from roadcuts and draft these data into cross sections for presentation of detailed stratigraphic columns that are locally correlative. Seven roadcuts were …

The Effectiveness Of Mobile Eye-Tracking To Enhance Guided Show Cave Experiences, Jenna Michele Hammond

Masters Theses & Specialist Projects

Karst terrains are landscapes with a distinctive hydrology and set of landforms that arise from a combination of high bedrock solubility and well-developed secondary (fracture) porosity. Karst areas are easily polluted due to the rapid transport of unfiltered percolating water through the systems. While many individuals are able to identify karst landforms such as sinkholes and caves, an understanding of the interconnectedness of the surface and subsurface in karst landscapes, as well as the vulnerability of karst areas to degradation, is often limited. Show caves, which are caves made accessible to visitation by humans through built infrastructure, can serve as …

Nature And Origin Of Fissure Ore At The Porphyry-Epithermal Transition Zone Of The Bingham Canyon Porphyry Cu-Au-Mo Deposit, Utah, David Harris Tomlinson

Theses and Dissertations

Late-stage fissure-filling ore at the world class Bingham Canyon, Utah, porphyry copper deposit has long been recognized, but poorly studied. Physical and chemical characterization of the Pb-Zn-Cu-Ag-Au mineralized fissures in the porphyry-epithermal transition zone provides insight into the origin, timing, and controls of ore deposition. These sheared sulfide-rich fissures are dominated by pyrite and multiple generations of quartz, with lesser amounts of other sulfides and gangue minerals. Au (0.27 to 4.61 ppm) provides the most value to the ore in the transition zone. Host rocks include Eocene monzonite and Paleozoic limestone and quartzite"”all of which can contain economic ore bodies. …

Glacial-Interglacial Changes In The Thermocline Structure Of The Makassar Strait: Implications For Changes In The Indonesian Throughflow, Michael Lis

Theses and Dissertations

The Indo-Pacific Warm Pool exerts a strong influence on the global climate system because it partially controls heat and moisture exchange (pressure gradient) between the atmosphere and ocean, and thus, the intensity of the Indonesian throughflow (ITF) via the Makassar Strait, the main passage of water connecting the Pacific and Indian Oceans. The magnitude of ITF is reflected by the structure of the oceanic thermocline. Here, we use shell δ¹⁸O signatures and trace element composition of foraminifera (Globigerinoides ruber, Pulleniatina obliquiloculata, and Globigerinoides menardii) in two sediment records spanning the past 30 kya collected from …

Mantle Heterogeneity From The Mantle Plume Perspective: Sources Vs. Processes, Paul Béguelin

Theses and Dissertations

Oceanic island basalts (OIB) which are derived from mantle plumes sample a compositionally heterogeneous mantle, as revealed by their radiogenic isotope systematics. Isotope compositions recurring in distinct hotspots have been used to characterize the composition and heterogeneity of the mantle as well as the thermochemical structure of upwelling plumes, with the assumption that the isotope composition of erupted lavas directly reflects that of their mantle source.

Here I test how source transport, melting and hybridization in the upper mantle through space and time control the expression of deep mantle sources in erupted lavas. This work is focused on the Azores …

Multi-Stage Construction Of The Little Cottonwood Stock, Utah: Origin, Intrusion, Venting,Mineralization, And Mass Movement, Collin G. Jensen

Theses and Dissertations

The Little Cottonwood stock in central Utah, USA, is a composite granitic pluton that hosts the White Pine porphyry Mo-W deposit towards its northeast margin. The deposit is centered on the smaller White Pine intrusion, and associated igneous units include the Red Pine porphyry, phreatomagmatic pebble dikes, and rhyolite dikes. Twelve new U-Pb zircon LA-ICP-MS ages, for samples from this deposit and in pebble dikes from the nearby East Traverse Mountains, give peak ages of about 30 Ma and 27 Ma for the Little Cottonwood stock and White Pine intrusion, respectively, which correlate well with ages from previous studies. Ages …

Persistence Of Depositional Features In A Strongly Seasonal, Tide-Dominated Delta, Kallie Flaxington Brown

OES Theses and Dissertations

The Ganges-Brahmaputra-Meghna (GBM) Delta is one of the largest deltas in the world, covering more than 100,000 km². The GBM River system transports over one billion tons of sediment annually and delivers ~750 million tons to the Bay of Bengal, ~25% of which is advected by tides into the fluvially abandoned western delta plain. The Sundarbans National Forest (SNF) is located within the GBM Delta and, covering more than 10,000 km², is the world’s largest continuous mangrove stand. The present rate of sediment delivery allows the SNF platform elevation to keep pace with regional sea level …

3-D Potential Field Inversion Camp Clubhouse Crossroads Mafic Intrusive Pluton, Coastal Plain, South Carolina, Kubra Sibel Albayrak

Theses and Dissertations

The Central Atlantic Magmatic Province (CAMP) at the Triassic-Jurassic boundary, is the largest known igneous province in the world. However, the geometry and volume of CAMP intrusives under the Coastal Plain of the southeastern United States are poorly known. Under the Coastal Plain sediments of Georgia and South Carolina, the “J” seismic reflector was predicted to be produced by a CAMP lava flow. Recent studies of seismic and well data have shown that the “J” reflector is an unconformity and only locally a CAMP lava flow. In the Clubhouse Crossroads area of South Carolina, seismic reflection, seismic refraction, and well …

Fluvial Architecture And Reservoir Modeling Along The Strike Direction Of The Trail Member Of The Ericson Sandstone, Mesaverde Group In Southwest Wyoming, April Anahi Trevino

Theses and Dissertations

The Trail Member of the upper Cretaceous Ericson Sandstone, part of the Mesaverde Group, is exposed along hundreds of square kilometers through Wyoming along the flanks of several Laramide structural uplifts. This presents a unique opportunity to study the detailed architecture based on bed-scale heterogeneity and better assess the reservoir potential of these strata in outcrop exposure on a regional-scale, and to then relate these observations to producing fields nearby. The fluvial-dominated Trail Member formed as sediments traveled from the active Sevier thrust belt to the Cretaceous Interior Seaway, forming a basinward progradational clastic wedge along a relatively high gradient. …

Tracking Sediment Bypassing, Geomorphological Analysis, And Regional Sediment Management At Tidal Inlets, Tanya M. Beck

USF Tampa Graduate Theses and Dissertations

Tidal inlets on sandy shorelines separate barrier islands and serve as a conduit for transport of sand and water between embayments and oceans, seas, or other tidally influenced waterbodies. Tides and waves induce currents along the coastline that transport sediment across-shore and alongshore. Coastal managers must optimize barrier-inlet system stability while conserving limited sediment resources, and often base management decisions and engineering design upon geomorphic and numerical models that predict the morphological behavior of tidal inlets on short-to-medium timescales (years to decades). The overall goal of this study was threefold. First, to provide science-based practical guidance for regional sediment management …

Extreme Oxygen Isotope Zoning In Garnet And Zircon From A Metachert Block In Melange Reveals Metasomatism At The Peak Of Subduction Metamorphism, F. Zeb Page, Emilia M. Cameron, Clara Margaret Flood, Jeffrey W. Dobbins, Michael J. Spicuzza, Kouki Kitajima, Ariel Strickland, Takayuki Ushikubo, Christopher G. Mattinson, John W. Valley

Faculty & Staff Scholarship

A tectonic block of garnet quartzite in the amphibolite-facies melange of the Catalina Schist (Santa Catalina Island, California, USA) records the metasomatic pre-treatment of high-delta O-18 sediments as they enter the subduction zone. The block is primarily quartz, but contains two generations of garnet that record extreme oxygen isotope disequilibrium and inverse fractionations between garnet cores and matrix quartz. Rare millimeter-scale garnet crystals record prograde cation zoning patterns, whereas more abundant similar to 200-mu m-diameter crystals have the same composition as rims on the larger garnets. Garnets of both generations have high-delta O-18 cores (20.8 parts per thousand-26.3 parts per …

Detrital Zircon Geochronology Of Paleoproterozoic Sedimentary Rocks From The Upper Huronian Supergroup, Canada, Carolyn M. Hill, Don W. Davis, Patricia L. Corcoran

Western Research Forum

The Huronian Supergroup is a well-known succession of primarily sedimentary rocks exposed north of Lake Huron. Deposition of the succession is constrained between 2450 and 2220 Ma (million years), which corresponds with Earth’s rise of atmospheric oxygen, however the depositional timing of the uppermost formations cannot be refined further due to a lack of interbedded volcanic rocks. A geochronological study of detrital zircon grains from sandstone and claystone beds from the two youngest Huronian formations, the Gordon Lake and Bar River formations, was completed in order to confine the maximum age of deposition.

Zircon is a mineral that commonly forms …

Rethinking Map Literacy And An Analysis Of Quantitative Map Literacy, Ming Xie

USF Tampa Graduate Theses and Dissertations

Maps are increasingly being used in traditional and virtual media, and civic discourse on political, social, and environmental issues, among others, is more and more becoming influenced by them. The often-used expression of a “picture tells a 1000 words” has never been so apt in our progressively more visual world. Despite this increased role and importance of maps, map literacy, as a field of research, remains rather underdeveloped. This is especially so for thematic maps, the very type of map that is finding increasing currency in discourse. As part of this under-developed nature of map literacy, the quantitative skills used …

Effects Of Heat Treatment Of Spinels As Determined By Vis/Nir And Raman Spectroscopy And Xrd, Jill Reale, Dr. Michael B. Wolf

Celebration of Learning

Heat treatment is done to improve the color and clarity and, therefore, the value of gemstones. The objectives of this study include observing color and inclusion changes in pink spinels after heat treatment, and analyzing structural changes within differently colored spinels using Raman Spectroscopy and X-ray diffraction with a Paris Edinburgh Press. We expected the heat treatment to yield color changes and fading of small inclusions. Cut and polished spinels were heated to 1400C for 2 days or 850C for 3 days. Future experiments involve 800C, 750C, and 700C all for 1 week, 1500C for 4 days, and 1600C for …

Dextral, Normal, And Sinistral Faulting Across The Eastern California Shear Zone-Mina Deflection Transition, California-Nevada, Usa, Kevin Delano, Jeffrey Lee, Rachelle Roper, Andrew Calvert

All Faculty Scholarship for the College of the Sciences

Strike-slip faults commonly include extensional and contractional bends and stepovers, whereas rotational stepovers are less common. The Volcanic Tableland, Black Mountain, and River Spring areas (California and Nevada, USA) (hereafter referred to as the VBR region) straddle the transition from the dominantly NW-striking dextral faults that define the northwestern part

of the eastern California shear zone into a rotational stepover characterized by dominantly NE-striking sinistral faults that define the southwestern Mina deflection. New detailed geologic mapping, structural studies, and 40Ar/39Ar geochronology across the VBR region allow us to calculate Pliocene to Pleistocene fault slip rates and test predictions for the …

The Antiquity Of The Sahara Desert: New Evidence From The Mineralogy And Geochemistry Of Pliocene Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Juan F. Betancort, Alejandro Lomoschitz

United States Geological Survey: Staff Publications

The Sahara is the largest warm desert in the world, but its age has been controversial, with estimates ranging from Miocene to Holocene. Mineralogical and geochemical data show that paleosols of Pliocene to mid- Pleistocene age on Fuerteventura and Gran Canaria in the Canary Islands have developed in part from inputs of dust from Africa. These paleosols contain quartz and mica, minerals that are abundant in African dust but are rare in the basaltic rocks that dominate the Canary Islands. Trace elements with minimal mobility, Sc, Cr, Hf, Th, and Ta as well as the rare earth elements, show that …

Bleached Chondrules And The Possible Influence Of Aqueous Alteration, Robert P. Kostynick

Geology Undergraduate Honors Theses

Aqueous alteration, chemical or petrologic change through the addition of water, is a proposed secondary effect of ordinary chondrites. Some minimally metamorphosed chondrites have been noted to have strong signs of aqueous alteration (Weisberg et al., 2006), but the degree of the effect in other chondrites is not clear. There is a specific chondrule type called “bleached chondrules” in which aqueous alteration is proposed to occur in a widespread fashion for all metamorphic grades (Grossman et al., 2000). Using transmitted optical microscopy (OM) and scanning electron microscopy (SEM) at Portland State University, this report obtained chemical and petrological data of …

Deformation Conditions During Syn-Convergent Extension Along The Cordillera Blanca Shear Zone, Peru, Cameron A. Hughes, Micah J. Jessup, Colin A. Shaw, Dennis L. Newell

Geosciences Faculty Publications

Strain localization across the brittle-ductile transition is a fundamental process in accommodating tectonic movement in the mid-crust. The tectonically active Cordillera Blanca shear zone (CBSZ), a ∼200-km-long normal-sense shear zone situated within the footwall of a discrete syn-convergent extensional fault in the Peruvian Andes, is an excellent field laboratory to explore this transition. Field and microscopic observations indicate consistent top-down-to-the-southwest sense of shear and a sequence of tectonites ranging from undeformed granodiorite through mylonite and ultimately fault breccia along the detachment.

Using microstructural analysis, two-feldspar and Ti-in-quartz (TitaniQ) thermometry, recrystallized quartz paleopiezometry, and analysis of quartz crystallographic preferred orientations, we …

Geothermometry Of H6 And L6 Chondrites And The Relationship Between Impact Processing And Retrograde Metamorphism, Michael Tyler Ream

Dissertations and Theses

Ordinary chondrites are the most common type of meteorite to fall to Earth and are composed of lithified primitive nebular materials which have experienced variable extents of thermal metamorphism and shock processing. They were subjected to radiogenic heating by incorporation of unstable short lived radionuclides such as ²⁶Al in the early solar system.

The relationship between metamorphism and impact processing in ordinary chondrites is not fully understood. An unresolved issue in the study of ordinary chondrites is whether their original parent bodies were fragmented by impacts into rubble-pile bodies while they were still hot, or whether they retained their …

Rare Earth Geochemistry Of Apatitic Fossils From The Middle-Upper Ordovician Southern Margin Of Laurentia, Rafael Adrian Villanueva

LSU Master's Theses

Widespread deposition of phosphate and a transition from tropical to cool water carbonates is seen throughout Middle-Upper Ordovician Nashville Dome area spanning the M4/M5 sequence boundary. Hypotheses explaining the onset of these lithologic changes have included the onset of glaciation, drawdown of CO₂ related to the Guttenburg Isotope Carbon Excursion (GICE), and siliciclastic weathering, yet none of these studies have provided definitive evidence that shows any of these are the sole factor driving paleoenvironmental changes across the M4/M5 boundary. In order to test whether rapid subsidence along the southeastern margin of Laurentia may have caused an influx of phosphate …