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2014

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Articles 991 - 1020 of 1044

Full-Text Articles in Earth Sciences

Exploring The Hydrogeologic Controls On Brackish Water And Its Suitability For Use In Hydraulic Fracturing: The Dockum Aquifer, Midland Basin Texas, Francisco Ruben Reyes Jan 2014

Exploring The Hydrogeologic Controls On Brackish Water And Its Suitability For Use In Hydraulic Fracturing: The Dockum Aquifer, Midland Basin Texas, Francisco Ruben Reyes

Open Access Theses & Dissertations

Water scarcity in arid regions can limit or impede certain hydrocarbon production activities, such as hydraulic fracturing and well drilling. The Midland Basin, a major oil-producing area in semi-arid far west Texas and the eastern sub-basin of the Permian Basin, is already impacted by limited freshwater availability. A typical tight oil well in the Midland Basin requires ~3.8-11.4 x 103 m3 of water per fracture treatment (Nicot et al., 2012). Despite draught conditions and limited resources, data for 2011 indicate freshwater comprises ~70% of the water used in hydraulic fracturing in the Midland basin. Thus, the Midland Basin represents an …


Long-Term Deformation In The Southern Rí­O Grande Rift As Inferred From Topographic And Uplifted Terraces, Linda K. Armour Jan 2014

Long-Term Deformation In The Southern Rí­O Grande Rift As Inferred From Topographic And Uplifted Terraces, Linda K. Armour

Open Access Theses & Dissertations

This study examines Basin and Range topography relating tectonic processes to topographic features. The observation that the terraces along either side of the Franklin Mountains were deformed and uplifted is a reflection of tectonic uplift. The uplift represents long-term deformation of the range. This led to the question of what shapes the deformation and does it represent differential subsidence into the Río Grande Rift or true uplift. A more regional study of the Sacramento, San Andres, and Guadalupe Mountains follows. Two papers form this Dissertation.

The Rí­o Grande Rift and the Franklin Mountains, in particular, are the subject of the …


Analyzing Stress Drops Of Earthquakes Near Wellington, New Zealand, Kyle Eugene Barnes Jan 2014

Analyzing Stress Drops Of Earthquakes Near Wellington, New Zealand, Kyle Eugene Barnes

Open Access Theses & Dissertations

Stress drop studies analyze the change of stress across faults before and after an earthquake. The goal of this study was to determine how stress drop varies throughout the Wellington region of the North Island of New Zealand. To the east of the North Island, the Hikurangi Trough obliquely subducts the Pacific Plate beneath the younger Australian Plate. Toward the southern end of the North Island and into Cook Strait the Pacific plate becomes more buoyant and the plate interface displays strong coupling as subduction diminishes into the strike-slip Marlborough fault system. Subduction of the Pacific plate ceases beneath the …


Impacting Earthquake Science And Geoscience Education: Educational Programming To Earthquake Relocation, Tina Louise Carrick Jan 2014

Impacting Earthquake Science And Geoscience Education: Educational Programming To Earthquake Relocation, Tina Louise Carrick

Open Access Theses & Dissertations

This Dissertation is comprised of four studies: three related to research on geoscience education and another seismological study of the South Island of New Zealand. The geoscience education research is grounded in 10 years of data collection and its implications for best practices for recruitment and retention of underrepresented minority students into higher education in the geosciences. The seismological component contains results from the relocation of earthquakes from the 2009 Dusky Sound Mw 7.8 event, South Island, New Zealand.

In recent years, many have cited a major concern that U.S. is not producing enough STEM graduates to fit the forecasted …


Modeling Tidally Driven Coulomb Failure At Strike-Slip Linea On Europa, Marissa Elizabeth Cameron Jan 2014

Modeling Tidally Driven Coulomb Failure At Strike-Slip Linea On Europa, Marissa Elizabeth Cameron

Open Access Theses & Dissertations

The surface of Europa is crosscut by a dense network of fractures and there are many candidate faults for studying past tectonic activity. To better understand the role of tidal stress sources and implications for faulting on Europa, we investigate the relationship between shear and normal stresses at four fault zones: Agenor Linea, Rhadamanthys Linea, Conamara Chaos (Agave/Asterius Linea), and Astypalaea Linea, offering a unique comparison of geological activity of fractures residing in geographically diverse locations of Europa. Assuming tidal diurnal and non-synchronous rotation (NSR) stresses are the primary mechanisms for strike-slip tectonism, here we investigate the mechanics of Coulomb …


Seismic Characterization Of The J-Reflector Near The Meizoseismal Area Of The 1886 Charleston Earthquake For Lithologic Constraint, Craig Cunningham Jan 2014

Seismic Characterization Of The J-Reflector Near The Meizoseismal Area Of The 1886 Charleston Earthquake For Lithologic Constraint, Craig Cunningham

Theses and Dissertations

Investigations into the relationship between geologic structure and seismicity in and around the meizoseismal area of the 1886 Charleston earthquake have been ongoing since the 1970s. Seismic reflection profiles collected in this area display a prominent, laterally continuous, high amplitude, low frequency, two cycle reflection at ~0.7-1.2 s TWT, termed the "J" reflector, which has been correlated with Lower to Middle Jurassic tholeiitic basalt flows encountered in the Clubhouse Crossroads wells. The "J" reflector was also extended offshore onto the continental shelf. Recent reevaluation of sub Coastal Plain wells within the South Georgia Rift (SGR) Basin, including wells around the …


Comparative Recharge Rates Of Isolated And Riverine Wetlands, Chenille Hargrove Williams Jan 2014

Comparative Recharge Rates Of Isolated And Riverine Wetlands, Chenille Hargrove Williams

Theses and Dissertations

Isolated wetlands have a slightly depressed topography surrounded by an upland area. There is no direct surface water connection, as with riverine wetlands; however, there is a groundwater connection that allows isolated wetlands to have similar hydrologic functions to riverine wetlands. This study sought to compare surficial aquifer groundwater recharge rates of several isolated and riverine wetlands in the Coastal Plain of the Carolinas by evaluating soil characteristics, water table fluctuations, and precipitation from January 2012 - September 2012. Data analysis indicated no significant difference in mean recharge rates between the isolated and riverine wetlands at each study site. Whereas …


The Impact Of Changing Surface Ocean Conditions On The Dissolution Of Aerosol Iron, Matthew P. Fishwick, Peter N. Sedwick, Maeve C. Lohan, Paul J. Worsfold, Kristen N. Buck, Thomas M. Church, Simon J. Ussher Jan 2014

The Impact Of Changing Surface Ocean Conditions On The Dissolution Of Aerosol Iron, Matthew P. Fishwick, Peter N. Sedwick, Maeve C. Lohan, Paul J. Worsfold, Kristen N. Buck, Thomas M. Church, Simon J. Ussher

OES Faculty Publications

The proportion of aerosol iron (Fe) that dissolves in seawater varies greatly and is dependent on aerosol composition and the physicochemical conditions of seawater, which may change depending on location or be altered by global environmental change. Aerosol and surface seawater samples were collected in the Sargasso Sea and used to investigate the impact of these changing conditions on aerosol Fe dissolution in seawater. Our data show that seawater temperature, pH, and oxygen concentration, within the range of current and projected future values, had no significant effect on the dissolution of aerosol Fe. However, the source and composition of aerosols …


Did A Submarine Landslide Contribute To The 2011 Tohoku Tsunami?, David R. Tappin, Stephan T. Grilli, Jeffrey C. Harris, Robert J. Geller, Timothy Masterlark, James T. Kirby, Fengyan Shi, Gangfeng Ma, K.K.S. Thingbaijam, P. Martin Mai Jan 2014

Did A Submarine Landslide Contribute To The 2011 Tohoku Tsunami?, David R. Tappin, Stephan T. Grilli, Jeffrey C. Harris, Robert J. Geller, Timothy Masterlark, James T. Kirby, Fengyan Shi, Gangfeng Ma, K.K.S. Thingbaijam, P. Martin Mai

Civil & Environmental Engineering Faculty Publications

Many studies have modeled the Tohoku tsunami of March 11, 2011 as being due entirely to slip on an earthquake fault, but the following discrepancies suggest that further research is warranted. (1) Published models of tsunami propagation and coastal impact underpredict the observed runup heights of up to 40. m measured along the coast of the Sanriku district in the northeast part of Honshu Island. (2) Published models cannot reproduce the timing and high-frequency content of tsunami waves recorded at three nearshore buoys off Sanriku, nor the timing and dispersion properties of the waveforms at offshore DART buoy #21418. (3) …


The Great 2012 Arctic Ocean Summer Cyclone Enhanced Biological Productivity On The Shelves, Jinlun Zhang, Carin Ashjian, Robert Campbell, Victoria Hill, Yvette H. Spitz, Michael Steele Jan 2014

The Great 2012 Arctic Ocean Summer Cyclone Enhanced Biological Productivity On The Shelves, Jinlun Zhang, Carin Ashjian, Robert Campbell, Victoria Hill, Yvette H. Spitz, Michael Steele

OES Faculty Publications

A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and …


Phytoplankton And Nutrient Dynamics In A Tidally Dominated Eutrophic Estuary: Daily Variability And Controls On Bloom Formation, Ryan E. Morse, Margaret R. Mulholland, Todd A. Egerton, Harold G. Marshall Jan 2014

Phytoplankton And Nutrient Dynamics In A Tidally Dominated Eutrophic Estuary: Daily Variability And Controls On Bloom Formation, Ryan E. Morse, Margaret R. Mulholland, Todd A. Egerton, Harold G. Marshall

OES Faculty Publications

To better understand nutrient dynamics and factors that promote the initiation of algal blooms, the Lafayette River, a tidal subestuary of Chesapeake Bay that experiences seasonal algal blooms, was sampled daily for a period of 54 d in the fall of 2005. Three phytoplankton blooms (chl a concentrations exceeding twice the average of monthly measurements from 2000 to 2009) occurred during this period: a mixed bloom of Akashiwo sanguinea and Gymnodinium sp., a monospecific Skeletonema costatum bloom, and a monospecific Gymnodinium sp. bloom. Over the sampling period, nutrient concentrations increased following precipitation events and were elevated between bloom periods but …


Surface Complexation Of Monosubstituted Organoarsenicals On Hematite: Atr-Ftir Investigations, Md Abdus Sabur Jan 2014

Surface Complexation Of Monosubstituted Organoarsenicals On Hematite: Atr-Ftir Investigations, Md Abdus Sabur

Theses and Dissertations (Comprehensive)

Little is known about the surface chemistry of organoarsenic compounds with iron-containing materials commonly found in geosorbents and arsenic removal technologies. In this thesis, these organoarsenicals include aliphatic and aromatic arsenicals that historically have been used as herbicides, pesticides and in the poultry feed industry, respectively. Attenuated total internal reflectance Fourier transform infrared spectroscopy has been used to study the surface interactions of organoarsenicals at the molecular level under various environmentally-relevant conditions. Kinetic and thermodynamic parameters extracted from these molecular level experiments provide trends that are not observed in any published bulk experiments. Apparent initial rates of adsorption and desorption …


Crustal Thickness And Vp/Vs Beneath The Western United States: Constraints From Stacking Of Receiver Functions, Uranbaigal Purevsuren Jan 2014

Crustal Thickness And Vp/Vs Beneath The Western United States: Constraints From Stacking Of Receiver Functions, Uranbaigal Purevsuren

Doctoral Dissertations

"This study investigates crustal characteristics beneath the western United States. Crustal parameters, including crustal thickness (H), mean Vp/Vs, and the sharpness of the Moho as quantified by the amplitude of the P-to-S converted phases from the Moho, are measured at a total of 1000 permanent and portable broadband seismic stations using over 150,000 receiver functions recorded between 1988 and 2012. The study area is composed of a diverse set of tectonic provinces formed by a series of tectonic events, and is thus ideal for investigating crustal formation and modification by different tectonic processes. The resulting crustal thickness varies from …


Modelling The Subsurface Geomorphology Or An Active Landslide Using Lidar, Norbert H. Maerz Jan 2014

Modelling The Subsurface Geomorphology Or An Active Landslide Using Lidar, Norbert H. Maerz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.


Geospatial Data Pre-Processing On Watershed Datasets: A Gis Approach, Sreedhar Nallan, Leisa Armstrong, Barry Croke, Amiya K. Tripathy Jan 2014

Geospatial Data Pre-Processing On Watershed Datasets: A Gis Approach, Sreedhar Nallan, Leisa Armstrong, Barry Croke, Amiya K. Tripathy

Research outputs 2014 to 2021

Spatial data mining helps to identify interesting patterns from the spatial data sets. However, geo spatial data requires substantial data pre-processing before data can be interrogated further using data mining techniques. Multi-dimensional spatial data has been used to explain the spatial analysis and SOLAP for pre-processing data. This paper examines some of the methods for pre-processing of the data using Arc GIS 10.2 and Spatial Analyst with a case study dataset of a watershed.


Biomineralization Of Carbonates In Modern Microbial Sediments And Its Implications For Co₂ Sequestration, Varun Gnanaprian Paul Jan 2014

Biomineralization Of Carbonates In Modern Microbial Sediments And Its Implications For Co₂ Sequestration, Varun Gnanaprian Paul

Doctoral Dissertations

"Several bacterial species influence carbonate mineral precipitation by modifying pH, alkalinity, Ca²⁺ activity and by providing nucleation sites for mineralization. Two studies have been undertaken to explore microbial influence in the mineralization of carbonates. In the first study, the ability of sulfate-reducing bacteria (SRB) to induce carbonate mineralization was investigated as a means to enhance mineral sequestration of CO₂. Sulfate-reducing bacteria enriched from hypersaline Storr's Lake, The Bahamas; Lake Estancia, New Mexico; and Great Salt Plains Lake, Oklahoma, were tested in reactors under varying CO₂ concentrations. Carbonate mineral precipitation was achieved only in reactors with Lake Estancia SRB community and …


Seismic Anisotropy And Mantle Flow Beneath Africa And Arabia, Ahmed Abdalla Elsheikh Jan 2014

Seismic Anisotropy And Mantle Flow Beneath Africa And Arabia, Ahmed Abdalla Elsheikh

Doctoral Dissertations

"In spite of numerous studies, the mechanisms for the rifting, uplifting, and volcanism on the African plate remain enigmatic. The most popular hypotheses proposed for explaining these tectonic phenomena involve edge-driven small-scale mantle convection and the thermal or dynamic effects of one or more mantle plumes. In this study we use continental scale shear-wave splitting (SWS) measurements to provide additional constraints on the various models of rifting, uplifting, and volcanism of the Cameroon Volcanic Line (CVL) and the Arabian plate. The splitting of P-to-S converted phases at the core-mantle boundary on the receiver side (XKS including PKS, SKKS, and SKS) …


A Receiver Function Study Of Crust Thickness And Composition Beneath The Southwestern United States, Si Wu Jan 2014

A Receiver Function Study Of Crust Thickness And Composition Beneath The Southwestern United States, Si Wu

Masters Theses

"Over the past decades, the seismic structure of the crust and upper mantle of the southwestern United States was examined using an array of different methods. The structure and composition of crust received special attentions, most due to the hydrocarbon reserves in this area. Here new constraints on crustal evolution and structure models are provide by systematically analyzing 37,402 receiver functions recorded at 234 seismic stations on the southwestern United States. The results reveal that the Transitional Crust is characterized by a thin (29.0±1.0 km) crust, a low Vp/Vs ratio of 1.76±0.016 and a high amplitude (R) of P-to-S converted …


A Remote Sensing Investigation Of Elevated Sub-Horizontal Topographic Surfaces In The Wichita Mountains, Oklahoma, Liang Xue Jan 2014

A Remote Sensing Investigation Of Elevated Sub-Horizontal Topographic Surfaces In The Wichita Mountains, Oklahoma, Liang Xue

Masters Theses

"Multiple elevated horizontal to sub-horizontal topographic surfaces are present in the Wichita Mountains, Oklahoma. Elevated topographic surfaces, developed primarily on granite bedrock with gentle slopes of 0.5 to 7⁰,were investigated using 1) Digital Elevation Models (DEMs) extracted from NAD 27 UTM coordinates, 2) Google Earth imagery, and 3) USGS topographic maps. In the western Wichita Mountains prominent topographic surfaces at elevations of 720 ± 5 m, 685 ± 5 m, and 660 ± 5 m are well preserved on at least four different mountains (e.g., Solder's Peak, King Mt.) and can be correlated with similar surfaces on at least seven …


Pn Anisotropy Tomography Of The Colorado Plateau And Adjacent Areas, Shengyao Cheng Jan 2014

Pn Anisotropy Tomography Of The Colorado Plateau And Adjacent Areas, Shengyao Cheng

Masters Theses

"The Pn tomography method utilizes seismic waves that refract along the Moho interface to perform inversion in order to investigate velocity anomalies and seismic anisotropy in the uppermost mantle. Results from Pn tomography can provide important information about the composition, temperature, and tectonic processes beneath the study area. Over the past decades, numerous seismic and geologic studies have been conducted in the Colorado Plateau and its adjacent areas to reveal crustal and mantle structures and processes responsible for the diverse surface geological features and tectonic events that have occurred in this area. To investigate lateral variations in the uppermost mantle …


Shear-Wave Splitting And Mantle Deformation Beneath The Western Tibetan Plateau, Melissa Ann Ray Jan 2014

Shear-Wave Splitting And Mantle Deformation Beneath The Western Tibetan Plateau, Melissa Ann Ray

Masters Theses

"The Tibetan Plateau has been an enigma to the scientific community since scientists first began to focus their attention on the area. Numerous studies over the decades were conducted to address how the plateau formed, mostly in the central and eastern portions of the Tibetan Plateau. Many questions still remain regarding the western Tibetan Plateau, and this study will add constraints to the mechanisms which regulated the formation of the plateau.

Data was acquired from over 13,000 measurements from 172 stations covering the western region of the plateau encompassing the Qiangtang Terrane, the Lhasa Terrane, and the Himalayan Orogenic Zone. …


Coupled Sediment Yield And Sediment Transport Model To Support Navigation Planning In Northeast Brazil, Calvin Trebor Creech Jan 2014

Coupled Sediment Yield And Sediment Transport Model To Support Navigation Planning In Northeast Brazil, Calvin Trebor Creech

Wayne State University Dissertations

Deposition of sediment (shoaling) in commercial waterways is a major obstacle to maintaining sustainable riverine transportation of bulk goods (primarily agricultural and mining commodities). The rate of aggradation of sediment in a waterway is directly related to both the rate of sediment erosion from upland and river bank sources (sediment yield) and the energy in the river to effectively transport the sediment through the waterway system (sediment transport). Historically, methods used for waterway development have included trial and error or rules of thumb associated with river training structures and chute cut-off canals or engineering of navigation locks and dams. More …


An Investigation Of Rock Fall And Pore Water Pressure Using Lidar In Highway 63 Rock Cuts, Norbert H. Maerz Jan 2014

An Investigation Of Rock Fall And Pore Water Pressure Using Lidar In Highway 63 Rock Cuts, Norbert H. Maerz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.


High-Resolution Magnetic Susceptibility Measurements For Investigating Magnetic Mineral Formation During Microbial Mediated Iron Reduction, Estella A. Atekwana, Farag M. Mewafy, Gamal Z. Abdel Aal, D. Dale Werkema, Andre Revil, Lee D. Slater Jan 2014

High-Resolution Magnetic Susceptibility Measurements For Investigating Magnetic Mineral Formation During Microbial Mediated Iron Reduction, Estella A. Atekwana, Farag M. Mewafy, Gamal Z. Abdel Aal, D. Dale Werkema, Andre Revil, Lee D. Slater

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Disimilatory iron-reducing bacteria play an important role in the reduction of Fe(hydr)oxides and the production of secondary solid-iron mineral phases that can have magnetic properties. Magnetic susceptibility can therefore play an important role in identifying zones where microbial-mediated iron reduction is occurring. We investigated the magnetic susceptibility variations in a hydrocarbon-contaminated aquifer where methanogenesis and iron reduction are the main biogeochemical processes. Our objectives are to (1) determine the variability of magnetic susceptibility, (2) determine the hydrobiogeochemical controls on the magnetic susceptibility variability, and (3) evaluate the use of magnetic susceptibility as a viable technique for identifying zones where the …


Geoneutrino Production Of The Northern Black Hills, South Dakota, United States Of America, Eric Eric Zimney Jan 2014

Geoneutrino Production Of The Northern Black Hills, South Dakota, United States Of America, Eric Eric Zimney

Theses and Dissertations

Current neutrino observatories operate underground to isolate the detector from cosmic rays and background radiation. However, background radiation from local sources has yet to be accounted for. Current models for neutrino contributions from terrestrial rocks are formulated from bulk compositional estimates of the whole Earth. To better understand local background radiation from geologic sources surfaces rocks were collected throughout the area surrounding the Homestake Mine, South Dakota, home of the Sanford Underground Research Laboratory. The surface rocks were analyzed for radioactivity and neutrino luminosity, producing heat maps indicating the levels of neutrino production throughout the area. The area around the …


Electron Donor Contributions To Denitrification In The Elk Valley Aquifer, North Dakota, Amanda M. Krieger Jan 2014

Electron Donor Contributions To Denitrification In The Elk Valley Aquifer, North Dakota, Amanda M. Krieger

Theses and Dissertations

Six denitrification tracer tests were performed over eight and a half years in in situ mesocosms (ISMs) in the Elk Valley Aquifer (EVA) in east-central North Dakota. Groundwater samples were analyzed to determine how much nitrate was lost beyond that explained by dilution of the bromide tracer. Additional losses were attributed to denitrification. The denitrification rates varied from 0.10 to 0.23 mg N/L/day for the six tests. In general, the major electron donors for denitrification are organic carbon (OC), pyrite (FeS2), and ferrous iron silicate minerals. In the EVA tracer tests, increases in sulfate indicated that the oxidation of pyrite …


Elemental Chemostratigraphy Of The Three Forks Formation, Williston Basin, North Dakota, Brian R. Murphy Jan 2014

Elemental Chemostratigraphy Of The Three Forks Formation, Williston Basin, North Dakota, Brian R. Murphy

Theses and Dissertations

The Three Forks Formation of the Williston Basin in northwestern North Dakota is an Upper Devonian stratigraphic unit unconformably overlain by the Bakken Formation. It consists principally of dolostone, shale and anhydrite. The Three Forks is a productive tight oil resource play, which in recent years has been increasingly targeted and developed as part of the unconventional Bakken Petroleum System. Core analysis via energy dispersive x-ray fluorescence (ED-XRF) is a non-destructive, high-resolution chemostratigraphic data collection method that has been used here to produce concentration logs which reflect both lithologic heterogeneity and paleoredox conditions for the Three Forks Formation. These geochemical …


Changes In Climate And Moisture Availability In The Antarctic Eocene, Oligocene, And Miocene: Evidence From Palynological And Stable Isotope Geochemical Analyses Of The Shaldril And Andrill Cores, Kathryn Whitney Griener Jan 2014

Changes In Climate And Moisture Availability In The Antarctic Eocene, Oligocene, And Miocene: Evidence From Palynological And Stable Isotope Geochemical Analyses Of The Shaldril And Andrill Cores, Kathryn Whitney Griener

LSU Doctoral Dissertations

Prior to the Late Eocene, the Antarctic continent experienced lush vegetation under temperate conditions. Just before the Eocene/Oligocene Boundary, the climate of the southernmost continent began to deteriorate dramatically. This cooling trend largely continued until most Antarctic vegetation disappeared, ~13.85-12.8 Ma. Classifying the nature and cause of Antarctica’s drastic climate change is essential for furthering our knowledge of Earth’s history, and also for grasping the potential effects of current and future climate shifts. Here, I present evidence from three new palynomorph-centric studies that deepen our understanding of Antarctic earth science, climate change, and of climate proxies. The first study involved …


Contractional Tectonics: Investigations Of Ongoing Construction Of The Himalaya Fold-Thrust Belt And The Trishear Model Of Fault-Propagation Folding, Hongjiao Yu Jan 2014

Contractional Tectonics: Investigations Of Ongoing Construction Of The Himalaya Fold-Thrust Belt And The Trishear Model Of Fault-Propagation Folding, Hongjiao Yu

LSU Doctoral Dissertations

This dissertation focuses on the kinematic evolution of contractional tectonics: the Himalayan fold-thrust belt along the collisional orogenic belts, and growth of the basement-cored monoclines in Colorado Plateau. Ongoing Himalayan growth is generally thought to be dominated by duplexing and/or extrusion processes. Duplexing models highlight accretion of material from the subducting plate to the over-riding orogenic wedge, whereas extrusion models focus on up-dip translation of a block bounded by out-of-sequence faults. Here, a primary outstanding question involves the uncertain relationship of the Berinag thrust and the Tons thrust, structures with displacements of >80 km and >40 km, respectively. The uncertainty …


Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth Jan 2014

Untangling Earth System Responses Recorded In Sulfate's Sulfur And Oxygen Isotopes At The Dawn Of Multicellular Life And Today, Bryan Alan Killingsworth

LSU Doctoral Dissertations

Major Earth system perturbations in the deep past and today are recorded in sulfate sulfur and oxygen isotopes, as examined here in three cases. (1) Sedimentary sulfate record of the “Marinoan Oxygen-17 Depletion” (MOSD) event, implies ultra-high CO2 atmosphere at ~635 Ma after global glaciation. MOSD duration is constrained by correlating its most complete record to radiometric dates. Barium sulfate layers in South China sediments show the MOSD in lower layers but persistently absent up section. Carbon-13 correlation locates the MOSD within dated intervals from other sites, yielding a 0 - 0.99 Myr duration. Thus, sedimentary constraint on this non-steady-state …