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- Iron; carbon; liquid; short-range structure; intermediate-range structure; diffusion; viscosity; high temperature - high pressure; HIGH-PRESSURE; CORE FORMATION; THERMOELASTIC PROPERTIES; TERRESTRIAL PLANETS; SOUND-VELOCITY; IRON CARBIDE; OUTER CORE; AB-INITIO; CARBON; VISCOSITY (2)
- Apatite (1)
- Appalachian (1)
- Asian Monsoon (1)
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- Beryllium-7 (1)
- Carbon accumulation (1)
- Carbonate Chemistry (1)
- Cave Systems (1)
- Crevasses; glacier flow; glacier geophysics; glaciological instruments and methods; seismology; SUBGLACIAL WATER-PRESSURE; SHORT-TERM VARIATIONS; COLLE GNIFETTI; ALPINE GLACIER; TRANSIT SPEED; ICE; FLOW; ICEQUAKES; OUTBURST; VELOCITY (1)
- DISSOLVED ORGANIC-MATTER; CHLOROPHYLL-A; COMMUNITY COMPOSITION; FRESH-WATER; BIOOPTICAL PROPERTIES; NUTRIENT LIMITATION; OPTICAL-PROPERTIES; NITROGEN-FIXATION; GROWTH IRRADIANCE; MISSISSIPPI RIVER (1)
- Deltas (1)
- Deposition (1)
- Detrital zircons (1)
- Direct Transfer (1)
- Dolostones; laser ablation ICPMS; rare earth elements; RARE-EARTH-ELEMENTS; ISOTOPIC EVIDENCE; VOLCANIC ASH; REE PATTERNS; PORE WATERS; DOLOMITIZATION; ORIGIN; SEAWATER; CARBONATES; LAURENTIA (1)
- Erosion (1)
- False River (1)
- Fine sediment (1)
- Ganges-Brahmaputra Delta; geochronology; river channel avulsion; relative sea-level rise and subsidence; sedimentary basin evolution; OPTICALLY STIMULATED LUMINESCENCE; GANGES-BRAHMAPUTRA DELTA; QUATERNARY SEDIMENTARY RECORD; HUANGHE YELLOW-RIVER; SEA-LEVEL; K-FELDSPARS; HOLOCENE; RADIOCARBON; QUARTZ; SINGLE (1)
- Geochronology (1)
- Geography (1)
- Geology (1)
- Gorai River (1)
- Himalaya (1)
- Hydrodynamics; Bangladesh; sediment transport; seasonal variability; mangrove forest; GANGES-BRAHMAPUTRA DELTA; SEA-LEVEL; CARBON SEQUESTRATION; MARSH GROWTH; BLUE CARBON; RIVER; TRANSPORT; ESTUARY; MANAGEMENT; MORPHOLOGY (1)
- Inventory (1)
- Karst; geochemistry; Nitrate; Chloride; springs; agriculture; NITRATE CONCENTRATIONS; ESCHERICHIA-COLI; FECAL BACTERIA; AQUIFER; CONTAMINATION; TRANSPORT; SPRINGS; QUALITY; SURVIVAL; FLOW (1)
- LA-ICP-MS (1)
- Laser ablation (1)
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Articles 1 - 26 of 26
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Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
Reinterpreting The Tectonic Model Of The Southern Part Of The Taconic Orogeny Through A Provenance Study Of Late Ordovician Sandstones, Juan Carlos Guerrero
LSU Master's Theses
A provenance study of quartz arenites that stratigraphically are closely associated with major Ordovician K-bentonites has been conducted in order to further our understanding of the tectonic setting of eastern Laurentia during the Late Ordovician. Using laser ablation ICP-MS, detrital zircons separated from Ordovician sandstone samples in the southeastern Appalachian Mountains (Virginia to Alabama) were dated using U-Pb geochronology. Analytical results show three dominate age ranges for the zircons from these sandstones: ~440-490 Ma, ~900-1300 Ma, and ~1300-1500 Ma. In addition, some zircon ages grouped into older ranges of ~1600-1800 Ma, ~1800-1900 Ma, and ~2600-2800 Ma. Zircon ages from ~900-2800 …
Sandy Dredge Pit Sedimentation – Characteristics And Processes In Caminada Borrow Area, Ship Shoal, Louisiana Shelf, Usa, Zehao Xue
LSU Master's Theses
Mississippi River Deltaic Plain’s barrier islands are undergoing rapid disintegration due to high rates of subsidence and a deficit in coastal sediment supply. To mitigate for barrier island land loss, Louisiana has implemented a restoration program that supplements coastal sediment deficits by introducing sand from outside of the active coastal system. Ship Shoal is an inner-shelf submarine shoal with large amounts of restoration quality sand that was dredged in 2013-2016 for the Caminada Headland Restoration Project in central Louisiana, USA.
Vibracore samples (1.5 - 3.5 m deep) collected in 2017 and 2018 in Caminada Borrow Area revealed new silts and …
Grids & Datums, Clifford J. Mugnier
Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Carol Wilson
Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Carol Wilson
Faculty Publications
Constraining time is of critical importance to evaluating the rates and relative contributions of processes driving landscape change in sedimentary basins. The geomorphic character of the field setting guides the application of geochronologic or instrumental tools to this problem, because the viability of methods can be highly influenced by geomorphic attributes. For example, sediment yield and the linked potential for organic preservation may govern the usefulness of radiocarbon dating. Similarly, the rate of sediment transport from source to sink may determine the maturity and/or light exposure of mineral grains arriving in the delta and thus the feasibility of luminescence dating. …
Neogene Chemical Weathering And Provenance Records Of The Western Himalaya Preserved In The Arabian Sea, Peng Zhou
LSU Doctoral Dissertations
Some tectonic models for the Himalaya emphasize the importance of surface processes in controlling the structural evolution. To investigate this tectonic–climatic interactions, and the weathering and erosion of the western Himalaya, International Ocean Discovery Program (IODP) Expedition 355 drilled two sites (site U1456 and U1457) in Laxmi Basin, which located in the Eastern Arabian Sea. In my research project, I plan to use a series of geochemical and geochronological methods on the sediment samples from the cores of these two sites, and sediments from an industrial borehole Indus Marine A-1, which near the Indus river mouth, to reconstruct a climatic …
Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang
Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang
Faculty Publications
Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …
Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang
Short- And Intermediate-Range Structure And Dynamics Of Fe-Ni-C Liquid Under Compression, Jianwei Wang
Faculty Publications
Properties of liquid Fe alloys under high-pressure conditions are crucial for understanding the composition, thermal state, and dynamics of Earth's core. Experiments on such liquids, however, are often performed under pressures far below those of the outer core, necessitating long extrapolations of experimental results to core conditions. Such estimates can be complicated by light elements possibly forming pressure-dependent molecular clusters that can significantly affect the physical properties of liquids as core conditions are approached. First-principles molecular dynamics simulations were employed to compute the properties of an Fe-Ni-C liquid with a composition of Fe3.7Ni0.37C at 1673 K and pressures from 0 …
Nature Of The Crust In The Northern Gulf Of California And Salton Trough, Patricia Persaud
Nature Of The Crust In The Northern Gulf Of California And Salton Trough, Patricia Persaud
Faculty Publications
In the southern Gulf of California, the generation of new oceanic crust has resulted in linear magnetic anomalies and seafloor bathymetry that are characteristic of active seafloor-spreading systems. In the northern Gulf of California and the onshore (southeastern California, USA) Salton Trough region, a thick sedimentary package overlies the crystalline crust, masking its nature, and linear magnetic anomalies are absent. We use potential-field data and a geotherm analysis to constrain the composition of the crust (oceanic or continental) and develop a conceptual model for rifting. Gravity anomalies in the northern Gulf of California and Salton Trough are best fit with …
Coupled Landscape And Channel Dynamics Across The Ganges-Brahmaputra Tidal-Fluvial Continuum, Southwest Bangladesh, Edwin Jefferson Bomer Iv
Coupled Landscape And Channel Dynamics Across The Ganges-Brahmaputra Tidal-Fluvial Continuum, Southwest Bangladesh, Edwin Jefferson Bomer Iv
LSU Doctoral Dissertations
The Ganges-Brahmaputra (G-B) Delta of Bangladesh and India is widely considered to be one of the most vulnerable coastal systems in the world, owing to locally-accelerated sea level rise and landscape modification by human activities. Recent research efforts have identified pronounced elevation differences between natural and embanked areas in the G-B tidal delta plain, suggesting that natural landscapes are keeping pace with sea-level rise while anthropogenic locations are actively subsiding. However, this observation represents a singular point in time, and longitudinal trends of surface elevation in these regions are presently unknown. For communities residing in upstream regions of G-B delta …
Intelligent Identification For Rock-Mineral Microscopic Images Using Ensemble Machine Learning Algorithms, Jonathan Shi
Intelligent Identification For Rock-Mineral Microscopic Images Using Ensemble Machine Learning Algorithms, Jonathan Shi
Faculty Publications
It is significant to identify rock-mineral microscopic images in geological engineering. The task of microscopic mineral image identification, which is often conducted in the lab, is tedious and time-consuming. Deep learning and convolutional neural networks (CNNs) provide a method to analyze mineral microscopic images efficiently and smartly. In this research, the transfer learning model of mineral microscopic images is established based on Inception-v3 architecture. The four mineral image features, including K-feldspar (Kf), perthite (Pe), plagioclase (Pl), and quartz (Qz or Q), are extracted using Inception-v3. Based on the features, the machine learning methods, logistic regression (LR), support vector machine (SVM), …
Joint Geodetic And Seismic Analysis Of Surface Crevassing Near A Seasonal Glacier-Dammed Lake At Gornergletscher, Switzerland, Louis Garcia, Karen M. Luttrell
Joint Geodetic And Seismic Analysis Of Surface Crevassing Near A Seasonal Glacier-Dammed Lake At Gornergletscher, Switzerland, Louis Garcia, Karen M. Luttrell
Faculty Publications
Seasonal lake Gornersee forms at the confluence of Gornergletscher and Grenzgletscher, Switzerland, and experiences outburst floods annually in midsummer. To study the interplay between lake drainage, glacier movement and crevasse activity, high-frequency seismometers and GPS receivers were deployed in networks near Gornersee during the summer ablation seasons of 2004, 2006 and 2007. We use a Rayleigh wave coherence method to locate 3289, 7939 and 4087 icequakes, respectively, primarily along well-defined surface crevasses. We calculate two-dimensional strains from triads of GPS stations and find mean differential strain rates of similar to 300 x 10(-6) d(-1) with diurnal variations up to 800 …
Multicomponent Model Of Crustal Stress At Cajon Pass, Southern California With Implications For Stress Field Heterogeneity, Elliott Conley Helgans
Multicomponent Model Of Crustal Stress At Cajon Pass, Southern California With Implications For Stress Field Heterogeneity, Elliott Conley Helgans
LSU Master's Theses
Earthquake processes in plate boundary settings are chiefly controlled by the in situ crustal stress field. Knowledge of the relative importance of various active processes acting on a fault system is necessary to understand the mechanics of faulting. This is of extreme importance to the Cajon Pass region of southern California, which may function as an earthquake gate, imposing control on large multifault ruptures. We model the in situ stress field at seismogenic depth in Cajon Pass by balancing the orientation of the modern stress field inferred from earthquake focal mechanisms against the superposition of the far field tectonic driving …
Seasonal Variability Of Forces Controlling Sedimentation In The Sundarbans National Forest, Bangladesh, Carol A. Wilson, E. J. Bomer
Seasonal Variability Of Forces Controlling Sedimentation In The Sundarbans National Forest, Bangladesh, Carol A. Wilson, E. J. Bomer
Faculty Publications
Southwest Bangladesh, located on the Ganges-Brahmaputra-Meghna delta, is experiencing the impacts of sea level rise (SLR) due to processes at both the local and global scale. In particular, regional alterations of the hydrodynamic network, due to embankment construction, have drastically altered effective SLR, placing millions of inhabitants at risk of prolonged inundation, and threatening the world's largest continuous mangrove stand, the Sundarbans National Forest (SNF). In order to effectively employ landscape recovery solutions, an understanding of local sediment transport and deposition is critical. This field-based study investigates the sediment dynamics between the mangrove platform and tidal channels of the SNF …
Rare Earth Geochemistry Of Apatitic Fossils From The Middle-Upper Ordovician Southern Margin Of Laurentia, Rafael Adrian Villanueva
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 …
Floodwater Impact On Galveston Bay Phytoplankton Taxonomy, Pigment Composition And Photo-Physiological State Following Hurricane Harvey From Field And Ocean Color (Sentinel-3a Olci) Observations, Eurico D'Sa
Faculty Publications
Phytoplankton taxonomy, pigment composition and photo-physiological state were studied in Galveston Bay (GB), Texas (USA), following the extreme flooding associated with Hurricane Harvey (25-29 August 2017) using field and satellite ocean color observations. The percentage of chlorophyll a (Chl a) in different phytoplankton groups was determined from a semi-analytical IOP (inherent optical property) inversion algorithm. The IOP inversion algorithm revealed the dominance of freshwater species (diatom, cyanobacteria and green algae) in the bay following the hurricane passage (29 September 2017) under low salinity conditions associated with the discharge of floodwaters into GB. Two months after the hurricane (29-30 October 2017), …
Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift
Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift
Faculty Publications
We calculated the sedimentary budget of the Northwest Sub-basin (NWSB), South China Sea for different geological times based on interpretations of four multichannel seismic profiles across the basin with constraints from International Ocean Discovery Program (IODP) Expeditions 367 and 368 drilling results. Sedimentation was generally dominated by regional tectonic events and climate change, but complicated by local tectonic events and geographic position, which resulted in a specific sedimentary budget in the NWSB compared with other marginal basins and the Southwest Sub-basin. The sedimentation rate was relatively low following the opening of the NWSB but increased gradually during the Middle Miocene, …
Differentiation Of Surface Water And Groundwater In A Karst System Using Anthropogenic Signatures, Joe Honings
Differentiation Of Surface Water And Groundwater In A Karst System Using Anthropogenic Signatures, Joe Honings
Faculty Publications
Surface water-groundwater interaction within a karstic system enhances contaminant transport, making karst aquifers susceptible to anthropogenic practices. Contaminated waters related to agricultural and animal husbandry in northwestern Illinois (USA) prompted this investigation. Six streams and five springs were sampled for 16 parameters to assess anthropogenic influences. Statistical analyses revealed differences in 13 of 16 parameters between the stream and spring waters. Rock-water interaction was identified as the dominant mechanism defining the chemistry for both waters, which were classified as Ca-Mg HCO3. Elevated nitrate as nitrogen (NO3-N), chloride (Cl-), sodium, and potassium concentrations indicate that human activities have influenced the quality …
Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner
Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner
LSU Master's Theses
Dissolved silica (DSi), plays an important role in regulating primary productivity of silicifying organisms, such as diatoms which precipitate hard parts composed of biogenic silica (bSi) in coastal and shelf ecosystems fed by major rivers. In the Northern Gulf of Mexico (NGOM), loading of nitrogen and phosphorous have increased compared to a decline in DSi in the Mississippi River. Continued decreasing in DSi loading could lead to limited diatom growth and production or shifts in community composition, therefore, it is important understand the role of benthic fluxes in providing silica to the overlying water column as there are few regional …
Transitional Granulite-Facies Mafic Xenoliths In The 2.8 Ga Trondjhemite-Tonalite-Granodiorite (Ttg) Gneisses Of The Eastern Beartooth Mountains, Mt/Wy: Evidence For Variable Fluid Interactions, Andrew W. Osborne
Honors Theses
No abstract provided.
Suspended Sediment Transport Revealed By Patterns In Turbidity And Electrical Conductivity Curves In Three Cave Systems In Missouri, Usa., Caroline M. Mierzejewski
Suspended Sediment Transport Revealed By Patterns In Turbidity And Electrical Conductivity Curves In Three Cave Systems In Missouri, Usa., Caroline M. Mierzejewski
LSU Master's Theses
In cave streams, the movement of sediment as suspended and bed loads are linked to the occurrence of precipitation events on the surface. During precipitation events, the discharge of the streams in the basin increases. As those surface streams flow into cave streams via sinkholes or fissures, the discharge in cave streams increase. In addition to changes in discharge, the response of the surface and cave streams to precipitation include changes in turbidity and electrical conductivity of the stream water.
Changes in turbidity (Tu), electrical conductivity (EC), and discharge (Q) of water in the cave stream can be used to …
Exploring Geochemical Proxies For Identifying Cryptic Sequence Boundaries In The Geologic Past Using Modern Bahamian Analogues, Evan B. Magette
Exploring Geochemical Proxies For Identifying Cryptic Sequence Boundaries In The Geologic Past Using Modern Bahamian Analogues, Evan B. Magette
LSU Master's Theses
Previous studies of carbonate diagenesis have suggested that bulk Sr concentrations and inorganic δ13C values may be a useful proxy for identifying cryptic sequence boundaries in meteorically altered limestones due to geochemical processes associated with carbonate mineral stabilization in cement precipitation in the meteoric diagenetic environment. However, it is possible that natural geochemical variation in sediments may produce geochemical shift which could be misinterpreted as a cryptic sequence boundary. To test this, the Two Pines roadcut containing a previously identified protosol on Eleuthera, Bahamas, which has been affected by vadose meteoric diagenesis was sampled for bulk geochemical analysis. …
The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory
The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory
LSU Doctoral Dissertations
Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. …
Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo
Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo
LSU Doctoral Dissertations
The lower plain of the Mississippi River Delta contains approximately five coastal sedimentary basins that are topographically defined, and one shelf-crossing depocenter (the Birds Foot Delta). These depositional systems receive varying quantities of sediment from fluvial and marine sources and have rates of coastal land loss that are roughly inversely proportional to fluvial sediment supply. To combat land loss along these regions, Louisiana has launched a historic campaign to sustain and regrow coastal lands using, in part, river sediment diversions. Fine sediments constitute the majority of sediment load in the Mississippi River, but are under-studied with respect to dispersal processes, …
Reflector Dip Trends In Seismic Sh-Wave Imaging Of A Modern Lower Mississippi River Point Bar, Adam Gostic
Reflector Dip Trends In Seismic Sh-Wave Imaging Of A Modern Lower Mississippi River Point Bar, Adam Gostic
LSU Master's Theses
Various studies of ancient point bars have noted that a relationship can be observed between the dip angle and grain size of point bar lateral accretion deposits, with the most mud-rich deposits tending to exhibit the greatest dip. No analysis and only cursory explanations for this relationship have been provided. Additionally, buried mid-channel bars are absent from typical models of point bar architecture.
We successfully image the architecture of late-stage point bar deposits with a near surface 2D seismic SH-wave reflection survey and generate an SH-wave velocity model of the subsurface in the study area in order to interpret the …
In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann
In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann
Faculty Publications
The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin is complex. Previous studies attributed dolomitization to various diagenetic factors and environments. In this study, high-resolution, in situ laser ablation inductively coupled mass spectrometry analysis of rare earth element patterns of dolomite was used to assess the diagenetic fluids responsible for dolomitization of the Ordovician Decorah Formation. Integrated geochemical data and petrographic evidence suggest that the dolostones are formed in two different diagenetic realms: shallow burial and hydrothermal. Shallow burial dolomites exhibit three distinct rare earth element patterns. Dolomite from the middle portion of the Guttenberg Member exhibits light …
Short Communication: The Topographic Analysis Kit (Tak) For Topotoolbox, Adam M. Fortes
Short Communication: The Topographic Analysis Kit (Tak) For Topotoolbox, Adam M. Fortes
Faculty Publications
Quantitative analysis of digital topographic data is an increasingly important part of many studies in the geosciences. Initially, performing these analyses was a niche endeavor, requiring detailed domain knowledge and programming skills, but increasingly broad, flexible, open-source code bases have been developed to increasingly democratize topographic analysis. However, many of these analyses still require specific computing environments and/or moderate levels of knowledge of both the relevant programming language and the correct way to take these fundamental building blocks and conduct an efficient and effective topographic analysis. To partially address this, we have written the Topographic Analysis Kit (TAK), which leverages …