Geomorphology Commons^™

Private Sand Mining In The Mississippi River: Sediment Budget And Morphology Implications Between Baton Rouge And Belle Chasse, Louisiana, Brett Mcmann

LSU New Orleans Theses and Dissertations

This analysis examined how private sand mining within the Mississippi River between Baton Rouge, LA and Belle Chasse, LA affected its sand budget from 2004-2012.

Records assembled indicated that private mining removed an annual average of 2.8 million cubic yards of sand. A HEC-RAS one-dimensional sediment transport model was utilized to assess this practice. Three scenarios were simulated: a baseline without mining, conditions reflecting documented mining rates, and a hypothetical case with excessive extraction.

Results suggest that private mining constituted approximately 26 percent of the total sand deficit between Baton Rouge and Belle Chasse. Mining appeared to cause localized changes …

New Constraints On The Stratigraphic Architecture And Evolution Of Mississippi River Delta Lobe Activity: Barataria Basin, Southeastern La, Wilke Coleman

LSU New Orleans Theses and Dissertations

Barataria Basin is a shallow water, interdistributary estuary that has evolved in response to dynamic depositional regimes governed by distributary avulsion and reworking of sediments by coastal processes. In the Mississippi River delta plain, the migratory nature of the River has produced an evolving landscape constructed through episodes of regressive and transgressive sedimentation. These processes produce unique depositional signatures in the stratigraphic record, however the transgressive component of the delta cycle often results in obliteration of the regressive phase. This study uses a modern suite of geophysical and sediment core data to construct a revised geologic framework in Barataria Basin, …

Storm Intensity And Forward Speed Controls On Back-Barrier And Shoreface Sediment Dynamics Along The Louisiana Coast, Md Mohiuddin Sakib

LSU New Orleans Theses and Dissertations

High energetic storms import sediment to back-barrier bays and marshes and produce a perennial footprint that contributes to the long-term evolution of the inner shelf, bays, and marsh platform. The magnitude of sedimentation in back-barrier bays and marshes varies with storm characteristics (e.g., storm intensity, forward speed, size, and track). However, quantifying the impacts of storm characteristics on the sediment exchange between the inner shelf, bays, and marshes and documenting the resulting net sediment import and export patterns across these interfaces remains largely unexplored. Here we applied a calibrated Delft3D hydrodynamics and sediment transport model to a microtidal bay-marsh complex …

Facies Analysis Of Terrebonne Basin Using Vibracores And Chirp Seismic Data, Joseph M. Hankerson

LSU New Orleans Theses and Dissertations

This study was conducted in upper and lower Madison Bay as well as Lake Boudreaux in Terrebonne basin located in southcentral Louisiana. This region is part of the recently abandoned Lafourche delta complex (0.6-0.8 kyr). Much of coastal Louisiana is comprised of formerly active delta complexes of the Mississippi River that have undergone subsequent reworking. As more restoration actions are being considered to combat land loss in coastal Louisiana, exploring the framework of a recently abandoned delta complex could aid in these plans. Utilizing core descriptions and CHIRP seismic data, facies analysis was performed to produce cross sections that display …

The Impact Of Shoreline Stabilization On Sediment Supply And Ecogeomorphology: Assessing Marsh Response To Altered Wave Energies, Lake Borgne, Louisiana, Jessica J. Villers

LSU New Orleans Theses and Dissertations

Shoreline protection structures are a common response to lateral erosion in marshes, but limited studies exist on how they influence sediment supply and the resulting ecogeomorphology. This study investigates the impacts of marine mattresses, geotextile cages filled with riprap, in Lake Borgne, LA. A field study was conducted during cold front passages at a site with marine mattresses and a proximal control site without, collecting measurements of water depth, wave energy, lateral erosion, sediment accumulation, vegetation, and sediment characteristics. Wetlands with marine mattresses attenuated waves more than their natural marsh edge counterparts, which have limited conditions favorable for sedimentation. However, …

Fine Grained Delta Front Sediment Transport, Sarah Noel

LSU New Orleans Theses and Dissertations

Insights into transformative coastal processes are unlocked though understanding sediment transport mechanisms in fine-grained delta front environments. Movement of fine-grained sediments on delta fronts is not wholly explained through advection settling models. While advection settling models generally assume deposition into a still body, numerical modeling of sediment re-entrainment suggests there may be tidal, wave, and/or non-steady hydrograph influences allowing particles to reach greater distances by altering the decelerating velocity field. This research explores both an advection settling model and a mass conservation Rouse profile model to understand the irreducible delta front processes controlling sediment deposition. Using field data collected on …

Evolution Of The Magnolia Growth Fault: An Evaluation Of Cenozoic Activity, Plaquemines Parish, Southeastern Louisiana, Jared S. Bullock

LSU New Orleans Theses and Dissertations

A geologic investigation of the Lake Hermitage area west of the Mississippi River in Plaquemines Parish, Louisiana suggests an active, regional growth fault has caused rapid local subsidence. The Magnolia growth fault is a down-to-the-south, deep-seated listric fault bounded to the west and east by two salt diapirs. Evidence from 3D seismic data, well logs, and biostratigraphy, in addition to local geomorphology, suggests the fault has been active since the Miocene and is causing submergence of wetlands on the hanging wall side. To investigate whether a correlation exists between deep-seated growth faults and subsidence at this location, near-surface data including …

Morphodynamics Of Transgressive Coastal Systems: Modeling Allogenic And Autogenic Response To Sea Level Rise, Storms, And Changes In Sediment Supply, Kevin C. Hanegan

LSU New Orleans Theses and Dissertations

Barrier islands are widespread and typically enclose landward basins connected to the ocean through tidal inlets. Low energy in the basin enables fine sediment accumulation and salt marsh formation. Sea Level Rise (SLR) causes loss of marshes due to their low elevations and inundation sensitivity. Both long-term trends in sediment supply due to SLR and episodic transfers of sediment due to storms are important to the sustainability of marshes and tidal basins. The trajectory of deltas, including the Mississippi River Delta (MRD), are also impacted by sediment supply. The redistribution of sediments (autogenic reorganization) within transgressive systems will determine their …

Forecasting The Development Of A Natural Levee Breach And Subsequent Sediment Distribution At Mardi Gras Pass, Louisiana, Joshua Hansen

LSU New Orleans Theses and Dissertations

In 2012, a breach in a natural levee occurred on the Mississippi River near the Bohemian Spillway, forming a new distributary named Mardi Gras Pass. Since its genesis, scientists from local universities and NGOs have been regularly performing bathymetric and bank surveys to track the channel’s expansion, as well as discharge surveys throughout the receiving basin. This study developed and implemented a hindcast simulation based on this wealth of data utilizing the morpho- and hydrodynamic model, Delft3D. This model was then used to create a 20-year forecast and a 1-year simulation without tidal and subtidal forces. The results demonstrated that …

Displacement Rates And Lateral Continuity Of Baton Rouge Fault System Segments In The Vicinity Of The East Orleans Land Bridge, Louisiana, Robert W. Mohollen Jr.

LSU New Orleans Theses and Dissertations

The Baton Rouge Fault System (BRFS) is a system of deep-seated, east-trending normal faults. Analysis of a 2-D industry seismic dataset in Lake Pontchartrain and two, 3-D datasets in Lake Borgne, revealed three faults that may show lateral continuity beneath the East Orleans Land Bridge (EOLB). Biostratigraphy from 33 oil/gas industry well logs were used for correlation with deep seismic data. BasinMod was used to generate a burial history of the Cenozoic strata. Cross sections of 22 collected vibracores with 500 yr BP interval isochron estimations, calculated from 17 vibracore samples of radiocarbon dated (C¹⁴) relict marsh organics …

Evolution And Stratigraphic Architecture Of Tidal Point Bars With And Without Fluvial Input: Influence Of Variable Flow Regimes On Sediment And Facies Distribution, And Lateral Accretion, Pricilla Souza

LSU New Orleans Theses and Dissertations

Tide-influenced point bars represent a significant proportion of shallow-marine deposits, commonly developed along meandering channels in most backbarrier and estuarine systems. However, sedimentological studies to characterize this type of deposit are still emerging. They often present very heterogeneous internal architectures which development is controlled by the complex flow patterns operating in tidal environments. The study of the sedimentological and morphological characteristics of these features provides better understanding of the hydrodynamic processes that shape coastal systems and control their evolution as well as it contributes to better reservoir potential prediction and production strategy optimization, as tidal point bars may represent hydrocarbon …

Middle Miocene To Holocene History Of The Delacroix Island Fault System, Jarrett Leigh Levesh

LSU New Orleans Theses and Dissertations

An in-depth field study of the Delacroix Island producing field illustrates the evolution of the east-trending Delacroix Island Fault during the last 13 My. Well log correlations and 3-D seismic interpretation of 22 subsurface bio-stratigraphic horizons across the fault reveal variable stratigraphic thicknesses and displacement. Wells, with well log curve data as shallow as 31 m (100 ft) below the surface, were used to calculate interval thicknesses, expansion indices, sediment accumulation rates, burial history and magnitudes of displacement. Through these analyses, a correlation was found between the positioning of ancient Miocene depocenters over Delacroix Island and a period of increased …

Geomorphic And Temporal Evolution Of A Mississippi Delta Flanking Barrier Island: Grand Isle, La, Julie A. Torres

LSU New Orleans Theses and Dissertations

Optically stimulated luminescence (OSL) dating beach ridge sediments is one method for resolving barrier island growth at intermediate scales (decades-centuries), information that is lacking for Louisiana. This research combines OSL, GPR, aerial imagery, and cores to document temporal and spatial evolution of a Louisiana barrier island.

Grand Isle is composed of beach ridges organized in distinct, unconformable sets that began forming 0.75 ka until 0.575 ka when deposition ceased, the ridges were partially eroded, and deposition resumed in a more eastward direction. The central ridges formed between 370±30 and 170±10 years ago at a rate of one ridge every 11.6 …

Seamless Lidar Surveys Reveal Rates And Patterns Of Subsidence In The Mississippi River Delta, Celeste E. Woock

LSU New Orleans Theses and Dissertations

Light Detection and Ranging (Lidar) data are used to report the temporal and spatial patterns of subsidence as well as the potential contributors to subsidence within the Barataria and Terrebonne Bays. In recent decades, subsidence in southeast Louisiana has become a topic of substantial and growing concern to the scientific community, the local residents, and all those invested in the region. Lidar data were acquired from the United States Geological Survey (USGS) and the LSU Center for Geoinformatics. The data has been manipulated to map the differenced Lidar, complete an instantaneous slope analysis, and determine the thickness of the Holocene …

The Effects Of Sediment Properties On Barrier Island Morphology And Processes: A Numerical Modeling Experiment, Brittany Kime

LSU New Orleans Theses and Dissertations

Barrier island restoration and nourishment is necessary for sustaining coastal systems worldwide. In the Mississippi River Delta Plain, the lack of sediment supply, relative sea level rise, and reworking of abandoned delta lobes promote rapid disintegration of barriers, which can contribute to mainland storm impacts. Barrier island restorations that utilize higher quality sediments (Outer Continental Shelf- OCS) are expected to exhibit higher resiliency, withstanding coastal erosion, event-induced erosion, and ongoing transgression when compared to barriers nourished using lower quality nearshore (NS) sands. Additionally, use of OCS sediments increases sediment supply by adding material to the system supporting increased barrier longevity …

Geomorphology Of Shell Ridges And Their Effect On The Stabilization Of The Biloxi Marsh, East Louisiana, Frances R. Crawford

LSU New Orleans Theses and Dissertations

Extensive shell ridges frame the edges of marsh platforms in parts of the Biloxi Marsh of southeast Louisiana. The exact sources of the shells in these accumulations have not been clearly identified but the most likely source is a combination of shells from modern offshore and shells excavated from buried St. Bernard delta deposits. Larger or fetch-protected ridges remain stable through time, whereas ridges facing open water are more mobile, moving as much as 38 m inland from July 2017 to January 2018. Behind stable ridges, marsh platform biomass is relatively unaffected. When ridges are mobile, vegetation is smothered, leaving …

Coupled Barrier Island Shoreline And Shoreface Dynamics, Benjamin S. Beasley

LSU New Orleans Theses and Dissertations

In Louisiana, barrier islands are undergoing morphological change driven by high rates of relative sea-level rise and interior wetland loss. Previous works utilized historical region-scale bathymetry and shoreline change analyses to assess coastal evolution. However, more localized assessments considering the role of sediment transport processes in regional evolution are lacking. This is essential to predicting coastal change trajectories and allocating limited sand resources for nourishment. Using bathymetric and shoreline data, 100-m spaced shore-normal transects were created to track meter-scale elevation change for 1880s, 1930s, 1980s, 2006, and 2015. An automated framework was used to quantify and track parameters such as …

Hydrodynamic Controls On The Morphodynamic Evolution Of Subaqueous Landforms, Timothy L. Nelson

LSU New Orleans Theses and Dissertations

The southern Chandeleur Islands are an ideal setting to study shoal evolution given their history of submergence and re-emergence. Here, numerical models shed light on the attendant processes contributing to shoal recovery/reemergence following a destructive storm event. Simulations of a synthetic winter storm along a cross-shore profile using Xbeach shows that convergence of wave-induced sediment transport associated with repeated passage of cold-fronts initiates aggradation, but does not lead to reemergence. A Delft3d model of the entire island chain shows that as these landforms aggrade alongshore processes driven by incident wave refraction on the shoal platform, backbarrier circulation and resulting transport …

An Investigation Into The Origin, Composition, And Commercial Significance Of A Sedimentary Subsalt Formation: Keathley Canyon, Gulf Of Mexico, David Aaron Brassieur

LSU New Orleans Theses and Dissertations

Sub-salt oil and gas formations in deep-water northern Gulf of Mexico are high priority targets. Advances in seismic processing allow for high-resolution, below-salt imaging. Understanding the modes of salt emplacement provide insight into sub-salt traps and potential drilling hazards.

A sub-salt sedimentary unit lies in the Keathley Canyon protraction. Autosutures created the transport-parallel lineaments of the upper surface of the unit. In addition, highly variable sediment aggradation rates created ramps, flats, and basal cutoffs along the base of the allochthon as salt and sediment competed for space. Seismic models identify modes of salt emplacement, salt/sediment interactions, and mechanisms responsible for …

Biloxi Marsh Platform Response Due To Meteorological Forcing, Rachelle Thomason

LSU New Orleans Theses and Dissertations

The Biloxi Marsh of the eastern Mississippi River delta plain is exposed to meteorological forces ranging from large-scale, mid-latitude cyclones to smaller scale storms and squalls. Each time that these marsh platforms are exposed to a storm event, the potential exists for either deposition or erosion to take place. This study examines the connection between wind speeds, stratigraphic composition, marsh edge morphology, and marsh edge erosion at 4 sites in the Biloxi Marsh. As much as 2.17 m of erosion were measured during the 9-month study with a maximum, averaged erosion rate of 0.03 m day^-1. Shell berm …

An Analysis Of The Physical And Cultural Landscape Of Grand Isle, Louisiana, Alexis Thomas

LSU New Orleans Theses and Dissertations

The town of Grand Isle, Louisiana, and its rich geographic history, can offer insight into the early history of the State of Louisiana and the establishment of the United States as a country, as well as the study of the formation of barrier islands and methods of land use with such areas. The following thesis presents a geographic, as well as a historical, analysis of Grand Isle’s history. It attempts to answer the following questions: What is the shape, form, and origin of the physical landscape of Grand Isle? How have humans interacted with the land and surrounding areas of …

Barrier Spit Evolution And Primary Consolidation Of Backbarrier Facies: West Belle Pass Barrier, La, John N. Kramer Iii

LSU New Orleans Theses and Dissertations

West Belle Pass Barrier is a barrier spit that formed during the last delta lobe progradation associated with the Lafourche delta complex. Located on the western flank of the Caminada-Moreau Headland, West Belle Pass Barrier and Raccoon Pass are located downdrift of the Belle Pass jetties. Morphological changes stemming from storms, jetty infrastructure, and an expanding tidal inlet are evaluated using historical shoreline data and imagery. Littoral transport around the jetties combined with inlet growth created a framework wherein sediment is transported through Raccoon Pass and sequestered as a flood-tidal delta. These events aided in the landward migration of West …

Submarine Channel Evolution Linked To Rising Salt Dome, Mississippi Canyon, Gulf Of Mexico, Rachel C. Carter

LSU New Orleans Theses and Dissertations

By examining halokinetics and channel evolution in a deep-water system, we investigate how submarine channel morphology is affected by changing seascape linked to diapirism. The study area is located in Mississippi Canyon, Gulf of Mexico (GOM), situated directly off the continental slope in a prominent salt dome region. Interactions of salt domes with submarine channels in the GOM are poorly documented. Utilizing 3D seismic data and seismic geomorphology techniques, a long-lived Plio-Pleistocene submarine channel system has been investigated to develop a relationship between variable phases of salt movement and plan-form morphology of preserved channels.

We suggest that halokinetics acts as …

Wave Transformation At A Saltmarsh Edge And Resulting Marsh Edge Erosion: Observations And Modeling, Kevin J. Trosclair

LSU New Orleans Theses and Dissertations

This study examines wind generated waves during winter storms, their transformation/attenuation near the marsh edge, and the resulting saltmarsh edge erosion. A simple numerical model for wave generation, transmission and marsh edge erosion was developed and validated against observations from Lake Borgne, Louisiana. Results suggest that meteorological conditions modify the local water depth via wind or wave setup and atmospheric pressure, thus exerting a first order control on the location of wave attack, which in turn determines the type of wave forces (shear vs. impact) that dominate the erosion process. Scarp failure follows, at a location determined by water level, …

Geomorphic Evolution Of Caminada Pass In Southeast Louisiana., Jordyn A. Spizale

LSU New Orleans Theses and Dissertations

Tidal inlets play a significant role in barrier island sustainability along the barrier islands of southern Louisiana. With increasing tidal prism, major changes are taking place within and adjacent to the inlets. The purpose of this thesis is to examine how Caminada Pass, a tidal inlet along the Caminada-Moreau headland, has evolved through time. Fundamental to this effort is evaluating which processes have contributed toward inlet evolution and what is the response of the inlet-bordering barrier island shorelines of Grand Isle and Elmer’s Island. This effort summarizes previous results and utilizes published bathymetric data, aerial photographs, vector shorelines, satellite images, …

Geomorphologic Evolution Of A Rapidly Deteriorating Barrier Island System With Multiple Sediment Sources: Eastern Isles Dernieres, Louisiana, 1887 To 2006, Benjamin T. Kirkland

LSU New Orleans Theses and Dissertations

Trinity, East, and Wine Islands make up the eastern half of the Isles Dernieres barrier arc in south-central Louisiana. Formed following the abandonment of the Lafourche delta complex, subsidence and storm erosion have led to rapid deterioration of the system. Since 1887, the land area of the islands has decreased seventy-seven percent, and the gulf shoreline has retreated landward more than a kilometer. Wave ravinement on the shoreface of the islands is responsible for the most sediment loss; liberated sediment travels longshore to tidal inlets. The dominant ebb tidal currents then transport the sediment to where it is deposited in …

Understanding Uplift Of The Ethiopian Plateau From Longitudinal Profile Analysis Of The Blue Nile Drainage System, Prabhat Chandra Neupane

LSU New Orleans Theses and Dissertations

The Ethiopian Plateau is one of the few tectonically-active regions on Earth that is situated in continental rift zones. About 1.6 km deep gorge of the Nile was carved by the Blue Nile River on the Ethiopian Plateau, as the plateau has been experiencing continuous uplift and exhumation in the Cenozoic. Here, we used quantitative analysis of longitudinal rive-profile forms and parameters (knickpoint and normalized steepness-index k_sn) of the Blue Nile tributaries to tease out regional tectonic signals.

244 knickpoints were examined in the tributaries, majority (>80%) of which are unassociated with lithology or geological structures. Knickpoint …