Earth Sciences Commons^™

Natural And Anthropogenic Impacts On Sediment Dynamics And Preservation In Contrasting Mississippi Deltaic Coastal Environments, Jiaze Wang

LSU Doctoral Dissertations

Deltas worldwide share the same sinking problem in face of pressure from natural and anthropogenic activities. Many restoration strategies are being planned or have been implemented in the coasts around the world. However, many conventional hard structure constructions are energy-intensive. There are also associated uncertainties and limitations on the effectiveness and sustainability of these restoration plans. Soft or ecological engineering strategies normally take advantage of or mimic the coastal system self-response and feedbacks to natural and anthropogenic activities. The successful implementation of soft strategies relies on process-based studies on the change of complex coastal system. In addition, post-implementation monitoring work …

Paleoenvironmental Reconstruction Using Coral Microatolls (Sp. Siderastrea Siderea) From The Gulf Of Gonâve, Haiti, Gilman Reno Ouellette Jr.

LSU Doctoral Dissertations

Natural and anthropogenic climate changes present unique and serious risks to society. In order to plan and implement adaptation and mitigation strategies successfully, regional manifestations of broad-scale climate changes must be understood robustly. The Caribbean region contains part of the Western Hemisphere Warm Pool (WHWP), a major sea surface temperature (SST) feature that plays a key role in North Atlantic climate. Climate variability in the Caribbean is captured poorly by climate models, due in part to a lack of continuous, multidecadal instrumental climate records from the region. I explored three research questions in this dissertation: Does non-systematic bias exist in …

Evidence Of Subglacial Brine Inflow And Wind-Induced Mixing From High Resolution Temperature Measurements In Lake Bonney, Antarctica, Jade Lawrence

LSU Master's Theses

Hypersaline brine beneath Taylor Glacier enters proglacial West Lobe Lake Bonney (WLB) subglacially as well as from Blood Falls, a surface discharge point at the Taylor Glacier terminus. The brine strongly influences the water column of WLB. Because of the extremely high salinities below the chemocline in WLB, density is determined almost entirely by salinity and temperature can be used as a passive tracer. Cold brine intrusions enter WLB at the glacier face and intrude in to the water column at the depth of neutral buoyancy, where they can be identified by anomalously cold temperatures at that depth. This study …

Combining Downhole And Sediment Logging To Understand Spatial Variability In Grain-Size, Facies, And Reservoir Quality Of A Large-Scale Mississippi River Point Bar, False River, Louisiana, Elizabeth D. Olson

LSU Master's Theses

Although the general processes by which meandering river point bars are constructed have been known for some time, there is a lack of clarity regarding why small-scale heterogeneities develop. This is especially true in the largest meandering river systems, which are equivalent to some of the most important hydrocarbon reservoirs in the world. In this study, we evaluate the stratigraphic architecture of the 80 km² False River Point Bar System on the Lower Mississippi River and use the knowledge gained to better comprehend point bar construction at different phases. Previous studies of small to medium-scale systems have been unable …

Floodplain Impacts On Water Quality: A Case Study In Southern Louisiana, Emily Delduco

LSU Master's Theses

The quantity and quality of dissolved carbon delivered to coastal margins by rivers is an important component of global carbon cycling. The Atchafalaya River (AR) discharges ~25% of the flow of the Mississippi River (MR) and the total flow of the Red River (RR) into the Gulf of Mexico (GoM) annually while flowing through the largest bottomland swamp in North America. This provides a unique opportunity to study floodplain impacts on dissolved carbon processes in a large river system. The research aimed to: (1) determine DIC and DOC transport and processing by a river swamp basin under varied seasons and …

How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution And Infilling Processes, Patrick Robichaux

LSU Master's Theses

As coastal environments become more susceptible to land loss through accelerating sea level rise and subsidence, new restoration methods harnessing borrowed sediment are more valuable than ever. Mud-capped dredge pits (MCDPs) are a relatively new source of restoration-quality sediment that has only recently been utilized for beach and barrier island restorations in Louisiana. Because MCDPs have been in use for less than two decades in only a handful sites, little is understood about their evolution over decadal timescales. To improve our understanding of MCDPs after they are dredged, we have conducted a suite of geophysical surveys including bathymetry, sidescan sonar, …

Paleoenvironmental Variation And Provenance Records From Neogene Deep Sea Sediment Of The South China Sea, Chang Liu

LSU Doctoral Dissertations

I employed several paleoenvironmental proxies by utilizing deep sea sediment from the largest marginal basin in east Asia, namely the South China Sea (SCS), to reconstruct the long term paleoenvironmental variation in SE Asia since the Neogene. Sediments deposited within the SCS were mainly delivered by several major fluvial systems whose catchment basins cover several geological blocks in SE Asia. By analyzing the sediment’s geochemical and mineralogical characteristics, several indices which are affected by the source of the sedimentary influx, as well as the weathering state could be built and applied to constrain my paleoenvironmental reconstructions

Two deep sea drilling …

When, How, And Why Did The West Antarctic Ice Sheet Retreat In The Ross Sea Since The Last Glacial Maximum Using Foraminiferal And Porewater Geochemistry, Matthew Decesare

LSU Doctoral Dissertations

The Antarctic Ice Sheets (AIS) began to retreat from their Last Glacial Maximum (LGM) position sometime after 19,000 years ago. However, the corrosive waters circulating around Antarctica has prevented the recovery of radiocarbon-dateable material, hindering the development of deglacial chronologies. During Expedition NBP1502B to the eastern Ross Sea, an unprecedented quantity of fossil foraminifera and bivalves were recovered. Radiocarbon-dated specimens have been used to constrain the timing of West-AIS retreat from Whales Deep basin and Ross Bank. Whales Deep samples show that the WAIS retreated from its LGM position on the continental shelf edge by 14,700 ± 400 calibrated radiocarbon …

Assessing Morphodynamics Of The Lower Mississippi River From 1985 To 2015 With Remote Sensing And Gis Techniques, Bo Wang

LSU Doctoral Dissertations

The Lower Mississippi River is one of the most highly engineered rivers in the world. The river is now completely regulated by a combination of levees, artificial cutoffs, bank revetments, and dike fields; however, the river engineering has also complicated the geomorphological response to the sediment brought in the river. This dissertation research examined morphodynamics of the middle portion of the Lower Mississippi River from Vicksburg, Mississippi (river kilometer: 737) to Red River Landing, Louisiana (river kilometer: 486) to elucidate river engineering effects on sediment transport, storage, and distribution. The Old River Control Structure (ORCS) diverts approximately 25% of the …

Overbank Deposition Of Sand And Mud Within Two Point Bars Bound By The Mississippi River Levee System: Implications For Coastal Restoration Sediment Budgets, Christopher Magliolo

LSU Master's Theses

As ongoing Mississippi River sediment diversion projects are being developed and planned, the availability of sand and mud for use in the lower Mississippi River Delta is being calculated and budgeted. This project attempts to quantify the amount of sand and mud being lost from the lower Mississippi River past the Old River Control Structure in the remaining unleveed floodplains, an area that encompasses 270 km². Two land masses were chosen along each bank of this reach of the Mississippi River: Raccourci Island (west bank) and the Cat Island National Wildlife Refuge (east bank). Seventeen sediment cores were …

Influences Of Hurricanes, Floods, And Organic Production On River-Delta Evolution Over Decadal To Centennial Time-Scales, Crawford M. White

LSU Doctoral Dissertations

Episodic overbank flooding and sediment resuspension events (such as cold front passages or tropical cyclones) are recognized as important natural components for wetlands maintaining vertical equilibrium with sea-level. However, the relative importance of these components to an anthropogenically unmodified delta complex remains unclear. This study uses sediment cores to describe the relative importance of these vertical accretion components the Lafourche and Balize Deltas of the Mississippi River. Existing wetlands of the abandoned lower Lafourche receive no direct fluvial sediment, but instead are supported by sediment resuspended by tropical cyclones and cold fronts that pass over them. Wetlands of the modern …

Investigating Core Shale Depositional Environments Of Late Pennsylvanian Cyclothems Utilizing Geochemical Proxies To Test The Superestuarine Model, Bryce A. Mathis

LSU Master's Theses

The Late Paleozoic Midcontinent Sea (LPMS) inundated vast areas of the North American interior during glacio-eustatic transgressions, depositing widespread black shales facies within the core shale intervals of major cyclothems. These black shale deposits are unique because no modern analogs can adequately explain the depositional environments and model for organic matter preservation across such vast ancient epicontinental settings. One possible explanation is that a superestuarine circulation system developed across the LPMS during humid interglacial phases, which promoted strong water column stratification and benthic anoxia.

The goal of this research was to test the validity of the superestuarine estuarine model and …

Spatial Variability Of The Depth To The Magma Reservoir Beneath The Yellowstone Caldera Inferred From Observations Of Seiche Loading Induced Strain, Kevin James Gryger

LSU Master's Theses

Seiche waves in Yellowstone Lake at ~78, ~51, and ~25 minute periods and heights <10 cm can cause measurable strain (< 40 ns) as observed on borehole strainmeters both near (<300 m) and far (~20 km) from the lake. Observations of the correlation between the seiche waves and the associated strain response can be used to constrain the rigidity of the upper crust, the depth to magma bodies in the subsurface, and the viscosity (related to melt percentage) of the magma bodies in place. Lake level was directly measured with campaign absolute pressure gauges deployed in the West Thumb basin, Breeze Channel, and central basin of Yellowstone Lake, and 13 large seiche events (¡Ý7 cm) were identified from these observations. Periodic strain transients were measured on borehole strainmeters in the caldera during the 13 large seiche events. The peak-to-trough amplitude and phase of the seiche wave and strain response were estimated by fitting a multi-frequency sinusoid to the time series over a 4-hour window during each seiche event. It was found that the relationship between an applied seiche load and the associated strain response is self-consistent and linearly proportional at each borehole strainmeter in the caldera. Over multiple seiche events the observed strain response is consistent with a modeled strain-field produced by a seiche load on a two-layered viscoelastic model defined by free parameters Young¡¯s modulus (E1), plate thickness (H), and shear modulus ratio (¦Ì2/¦Ì1). The two-layered viscoelastic model represents a solid upper crust overlying a partially molten body which may be small pockets of melt (<1 km thickness) or a larger magma reservoir. Results suggest crystallizing melt beneath Yellowstone caldera at depths (H) of ~4¨C8 km in the south-southeast and ~3-5 km in the north-northwest sections of the caldera. Temporal observations between strain meters, coupled with constraints of Young¡¯s and shear moduli suggest that melt in the shallow crust has a viscosity ¡Ü1013 Pa s.

Microseismic Event Characteristics Associated With The Spatial And Temporal Stages Of Hydraulic Fracture Growth In Laboratory Experiments, Abigail Arielle Maxwell

LSU Master's Theses

There are uncertainties in the exact mechanisms that occur during hydraulic fracture growth and the interactions of hydraulic fractures with pre-existing fractures. In some cases fracture growth is seen to be purely tensile and in others a combination of tensile and shear mechanisms. In order to develop a seismic model to explain fracture propagation, there is a need for a complete classification of the microseismic events occurring during fracturing using waveform characteristics such as frequency, duration and magnitude. This classification would allow for more accurate prediction of the behavior of the hydraulic fracture from its initiation to when it intersects …

Palynostratigraphy And Environmental Implication Of Organic-Walled Microfossils Recovered From Iodp Site U1435, Mitchell Clifford Gregory

LSU Master's Theses

Extensive studies have examined the syn- and post-rift sediments in the South China Sea and surrounding margins, but pre-rift, Eocene deposits are rare. Here we examine organic-walled microfossils from the South China Sea, recovered at Site U1435 of IODP Expedition 349 to provide palynostratigraphic control and characterize the environmental setting before, and in response to, the initiation of seafloor spreading in the basin ~33 Ma. The well preserved palynological assemblage recovered allow dating of sediments sampled at Site U1435. Units II and III are now subdivided in 4 subzones; Zone 1 is essentially barren, Zones 2 and 3A are assigned …

Shallow Shear-Wave Seismic Analysis Of Point Bar Deposits Of False River, Louisiana, Martial James Morrison

LSU Master's Theses

Current point-bar complex models do not include subsurface unit bars as a normal feature. This study provides evidence for a potential buried unit bar amongst point-bar sediments of the large-scale, modern-day False River point-bar complex of the Mississippi River. We collect, process and interpret a two-dimensional, 150-m-long CMP seismic reflection profile that cuts perpendicularly across a major discontinuity surface in the False River point bar complex. The seismic source consists of a ground recoil device that fires a shotgun shell horizontally, producing shear waves. Multiple field experiments demonstrated which type of source and receiver provided the least amount of noise, …

Sediment Infilling Of Louisiana Continental-Shelf Dredge Pits: A Record Of Sedimentary Processes In The Northern Gulf Of Mexico, Meg Cathlin O'Connor

LSU Master's Theses

Sediment cores were collected at continental-shelf sites of the Northern Gulf of Mexico off the coast of Louisiana to develop a better understanding of post-dredging evolution of mud-capped dredge pits. The two pits studied were Sandy Point (SP) and Raccoon Island (RI) (both with water depths of ~10m and dredged to ~ 15-20 m below water surface), which were dredged in 2012 and 2013 respectively. Vibracores and multicores were collected in 2015. Preliminary radiochemistry analyses identified Beryllium-7 distribution in multicore samples from both sites. SP1, the northwestern site in the Sandy Point dredge pit, showed 26 cm of 7Be penetration. …

The Relationship Between The Timing Of Hydrocarbon Generation Between The Bristol Bay Depositional Basin And The Port Moller Area And Southern Portion Of The Bristol Bay Basin Of The Alaska Peninsula, Claire Rochelle Jones

LSU Master's Theses

The Alaska Peninsula has been the target of oil and gas exploration throughout much of the 20th century. Although most exploration efforts have focused on the Cook Inlet area, the geological setting of the Alaskan Peninsula suggests that economically viable resources may be located further south on the northern side bordering Bristol Bay (Port Moller area). This study investigates the relation of petroleum system elements between the northern and southern section of the Alaskan Peninsula with a particular focus on the potential for petroleum accumulation on the southern section close to Herendeen Bay. The analysis included the integration of a …

Modelling And Observational Evidence For The Igneous Evolution Of The Elysium Volcanic Province On Mars, David Andrew Susko

LSU Master's Theses

A major knowledge gap exists on how eruptive compositions of a single martian volcanic province change over time. The Elysium Volcanic Province is a location of great geologic interest on Mars. Its predominantly Amazonian surface age (beginning 3.3 Ga), and its isolation in the northern hemisphere of Mars away from other volcano-tectonic regions, make it an ideal locale to investigate igneous compositions erupted during the most recent geologic period on Mars. Here, this work seeks to fill that gap by assessing the compositional evolution of Elysium as a major martian volcanic province in two related projects. The first project seeks …

In Search Of Antarctica's Last Vegetation Refugium Within The Mcmurdo Dry Valleys, David Rau

LSU Master's Theses

The McMurdo Dry Valleys, a hyper-arid cold polar desert located within the Transantarctic Mountains was once covered by vegetation. An in depth study of surface samples of various Neogene age, acquired throughout the Valleys, provide insight to the location of one of Antarctica’s last vegetation refugia. Boston University’s Antarctic Research Group has collected 82 surface samples from paleo lake sediments on 14 expeditions spanning 22 years in the McMurdo Dry Valleys. The ages of the samples are still not fully constrained, but 8 regions where samples were collected have been interpreted to range between 16.95 ± 0.17 to 4 Ma …

A Palynostratigraphic Investigation Of Holocene Coastal Texas Bays: Implications For Future Coastal Change, Shannon Marie Ferguson

LSU Doctoral Dissertations

Although the Gulf of Mexico is one of the most studied basins in the world, a majority of the focus has been driven by petroleum exploration and/or on seismic and sedimentological facies models. Rarely has the intent of previous studies been to characterize the Holocene climatic record of coastal Texas. Of those studies that discuss Holocene vegetation change, the majority focus on the Mississippi River Delta, the Edwards Plateau or central Florida, leaving an absence of insight to western Gulf of Mexico climate changes. The Texas coastline stretches 595 km across almost 4° of latitude and the strong northwestern precipitation …

Quaternary River Erosion, Provenance, And Climate Variability In The Nw Himalaya And Vietnam, Tara Nicole Jonell

LSU Doctoral Dissertations

The influence of Quaternary climate variation on sediment generation, storage, and transport in two mountainous Asian river basin was examined in the largest tributary to the upper Indus River in the Himalayan rain shadow, the Zanskar River basin (~15,000 km²), and the smaller, subtropical Song Gianh basin (<3,500 km²) of central Vietnam. Spatial patterns of erosion in the Zanskar River Basin were established to quantify the dominant controls on Quaternary sedimentation in the Himalayan rain shadow on the edge of the Tibetan Plateau. Glacial erosion and precipitation along the High Himalaya together dominate sediment production and transport …

Facies Reconstruction And Stratigraphy Of A Late Pleistocene Bald Cypress Forest Discovered On The Northern Gulf Of Mexico Continental Shelf, Suyapa Gonzalez-Rodriguez

Honors Capstones

No abstract provided.

Facies Reconstruction And Stratigraphy Of A Late Pleistocene Bald Cypress Forest Discovered On The Northern Gulf Of Mexico Continental Shelf, Suyapa Gonzalez

Honors Capstones

No abstract provided.

Stratigraphic Analysis Of Florissant Fossil Beds National Monument Using Magnetic Susceptibility, Geochemical Comparison, And Gamma Ray Spectroscopy, Jennifer Kenyon

Honors Capstones

No abstract provided.

Source Mechanism Analysis Of Single-Well Microseismic Data Using Full-Wavefield Moment Tensor Inversion, Trudy Watkins

LSU Master's Theses

Receiver angular coverage of microseismic sources occurring during hydraulic fracturing treatments is an important factor to consider when interpreting moment tensor inversion results. A horizontal receiver array can provide greater angular coverage of vertical failure planes than a vertical receiver array. The source orientation can be accurately determined if the array samples both sides of the failure plane. However, the compensated-linear-vector-dipole (CLVD) mechanism can be overestimated by up to ~40% for double-couple (DC) sources and the isotropic mechanism can be overestimated by ~70% for CLVD sources. Source mechanism constraints on the moment tensor inversion are used to mitigate the lack …

A Geochronological And Stratigraphic Reconstruction Of The Middle Barataria Bay Receiving Basin, Joseph Ethan Thomas Hughes

LSU Master's Theses

Barataria Bay, one of the largest receiving basins for the Mississippi deltaic complex, is the location of a proposed river-sediment diversion for delta restoration. In order to determine how the sediment in the receiving-basin may respond to diversion flows, twenty-five sediment vibracores were collected from a 115 km2 study area located near Myrtle Grove and Bayou Dupont, southeast of New Orleans, LA. These cores were subject to multiple tests, including gamma bulk density scans, grain size analysis, and loss-on-ignition, in order to identify the lithology and stratigraphy. In addition, 137Cs and 14C dating techniques were employed in order to construct …

Archean Geodynamic Conditions Using P-T Constraints Of The East Pilbara Craton Ttgs, Andrew Kody Webb

LSU Master's Theses

We know very little about the tectonic setting present during the Hadean, but based on studies of surviving Hadean zircons, we know that a Hadean protocrust must have been established by at least 4.4 Ga (Kemp et al. 2010), and it must have also been able to accommodate minimum melt conditions (Harrison 2005). Tectonic models for Earth during the Hadean and Archean follow two trends: uniformitarianism and non-uniformitarianism. Uniformitarian models (following the famed geological concept that the present is the key to the past) argue that Hadean zircons and Archean rocks formed via processes akin to modern-style oceanic crust production …

Metamorphic Conditions Of Aluminous Gneisses In The Sawtooth Metamorphic Complex, Idaho, Usa: Implications For The Middle-Lower Crust, Eleanor Wesley-Anne Smith

LSU Master's Theses

The Sawtooth Complex (SMC) of central Idaho contains metasedimentary units that elucidate the pressure-temperature conditions and potentially, the evolution of Precambrian crust in the northwestern United States. Petrographic analysis, whole rock geochemistry, and geothermobarometry combined with thermodynamic phase equilibrium modeling record a regional metamorphic pathway for SMC aluminous gneisses characterized by burial to middle-lower crustal levels with at least two deformational events, followed by a retrograde overprint. P-T conditions are generally consistent with the peak assemblage of SMC aluminous gneisses of bt + grt + sil + ilm + zrn + mnz ± pl ± qtz ± kfs ± ap …

Intracontinental Neotectonics: Case Studies From The Tian Shan Orogen And Kuqa Fold-Thrust Belt, Cindy M. Colón

LSU Doctoral Dissertations

This dissertation focuses on the kinematic properties of intracontinental deformation during short geologic time scales. Using three case studies this work characterizes active deformation at varying spatial scales within the continental interior of Eurasia. The far-field effect of the Cenozoic Indo-Asia collision is the driving force controlling deformation within the Eurasian continental interior. Active deformation across the intracontinental Tian Shan range challenges the plate tectonic model that proposes crustal deformation is concentrated along plate boundaries. This work further constrains the active kinematics of intracontinental motion that is necessary to understand the dynamics of the Eurasian intracontinental system. The two standing …