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2019

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Articles 211 - 240 of 408

Full-Text Articles in Geology

Sedimentary Budget Of The Northwest Sub-Basin, South China Sea: Controlling Factors And Geological Implications, Peter D. Clift Apr 2019

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 Apr 2019

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 …


Bedrock Topography Mapping Of The East Leroy And Climax 7.5’ Quadrangles, Mi Using Hvsr And Other Geophysical Methods, Tyler A. Norris Apr 2019

Bedrock Topography Mapping Of The East Leroy And Climax 7.5’ Quadrangles, Mi Using Hvsr And Other Geophysical Methods, Tyler A. Norris

Masters Theses

Geophysical methods were used to estimate bedrock depths below sedimentary cover and infer previously unknown features in two adjacent topographic quadrangles (Climax & East Leroy) in Michigan, USA. The study area contains mostly Mississippian Shale bedrock overlain by Wisconsin-aged glacial drift deposited during multiple glacial advances and retreats of the Saginaw Lobe (Laurentide Ice Sheet). These glacial events created complex landform assemblages that have only recently been mapped in detail near-surface, but are still poorly understood in the subsurface. Buried bedrock valleys typically contain coarse glacial sediment and thus are valuable aquifers, but these can be difficult to locate due …


Computer-Assisted Graphic Correlation Of Ordovician Conodonts And Graptolites From The Argentine Precordillera And Western Newfoundland Using Constrained Optimization (Conop9), Andrea Marie Bryan Apr 2019

Computer-Assisted Graphic Correlation Of Ordovician Conodonts And Graptolites From The Argentine Precordillera And Western Newfoundland Using Constrained Optimization (Conop9), Andrea Marie Bryan

Honors Theses

The correlation of rock units is the foundation of geological research. Correlation is the process of proving two geologic events are time equivalent. Most importantly, it is used to establish time boundaries in the geologic time scale. This paper uses computer assisted graphic correlation (CONOP9) to correlate the ages of graptolites and conodonts from the Ordovician found in rocks from the continent Laurentia, and arranges them in a composite range chart. These two organisms lived in different environments and, therefore, are found in different biofacies. The Argentine Precordillera and the western Newfoundland region are places where these two fossils co-exist …


Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson Apr 2019

Utilizing Geophysical Attributes To Investigate The Architecture Of A Pinnacle Reef Complex, Michigan Basin, Usa, Austin M. Johnson

Masters Theses

The Silurian Niagaran Pinnacle Reefs of the Michigan Basin retain their relevance after primary recovery of hydrocarbons and are excellent candidates for carbon dioxide sequestration, natural gas storage, and enhanced oil recovery. Due to the nature of carbonate rocks, these reef complexes are heterogeneous and lateral interpolation between observations in wells, is ambiguous. Ambiguity has led to large uncertainty and disagreement regarding reef architectures and their internal facies distributions. Previous models of these reef complexes have relied almost entirely on well logs and conventional core. This study focused on integrating 3D seismic reflection data to reduce uncertainty when delineating the …


Depositional Facies And Sequence Stratigraphic Model For The Silurian Reefs, Michigan Basin, Usa, Zaid N. Nadhim Apr 2019

Depositional Facies And Sequence Stratigraphic Model For The Silurian Reefs, Michigan Basin, Usa, Zaid N. Nadhim

Masters Theses

Depositional models for the Silurian reefs in the Michigan Basin suggest that internal facies are either (i) randomly distributed within a symmetrical reef structure, or (ii) highly asymmetrical and strongly controlled by paleo-wind direction. To further test the applicability of these models, internal facies distributions were mapped using high-resolution core and log data in two sets of Silurian reefs. The results suggest that the relationship between reef geometry, facies distribution and proposed paleo-wind direction is more inconsistent than recently proposed. More specifically, facies descriptions from the Silurian reefs suggest the following. First, overall reef geometry and facies distributions are not …


Thermal Maturation Modeling Of The Michigan Basin, Jack H. Hybza Apr 2019

Thermal Maturation Modeling Of The Michigan Basin, Jack H. Hybza

Masters Theses

Given present day heat flow and burial depths in the Michigan Basin, hydrocarbons should be immature. However, oil and gas are abundant within the basin. Our hypothesis is that thermal maturation distributions in the Michigan Basin can be explained by variations in proximity to the Midcontinent Rift (MCR) system, thermal cooling, crustal convection, high temperature fluid advection, and eroded overburden.

For each of the seven wells in this study, a geohistory plot is coupled with a range of geodynamic models to calculate the thermal and maturation histories of each sediment unit within the well. Backstripping was used to generate basement …


Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner Apr 2019

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 …


Water Systematics Of Samoan Peridotite Xenoliths, Aaron Wolfgang Ashley Apr 2019

Water Systematics Of Samoan Peridotite Xenoliths, Aaron Wolfgang Ashley

Theses and Dissertations

Water influences geodynamic processes such as melting, deformation and rheology. Yet its distribution in the oceanic upper mantle is primarily known indirectly from melt inclusions and glasses of erupted mantle melts (i.e. MORB and OIB). To constrain the mechanisms influencing the distribution of water in the mantle, we analyzed 15 peridotite xenoliths from Savaiʻi and 2 dunite xenoliths from Taʻū (Samoa) for water concentrations (by polarized FTIR) and major/trace elements. Savaiʻi peridotites are among the most melt depleted oceanic xenoliths recovered (degrees of melt depletion ≥15%). They show strong evidence of transient metasomatism by both carbonatite and silicate melts, with …


Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data, Ryan G. Smith, R. Knight Apr 2019

Modeling Land Subsidence Using Insar And Airborne Electromagnetic Data, Ryan G. Smith, R. Knight

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Land subsidence as a result of groundwater overpumping in the San Joaquin Valley, California, is associated with the loss of groundwater storage and aquifer contamination. Although the physical processes governing land subsidence are well understood, building predictive models of subsidence is challenging because so much subsurface information is required to do so accurately. For the first time, we integrate airborne electromagnetic data, representing the subsurface, with subsidence data, mapped by interferometric synthetic aperture radar (InSAR), to model deformation. By combining both data sets, we are able to solve for hydrologic and geophysical properties of the subsurface to effectively model the …


Nitrate Contaminant Tracing In Surface And Groundwater In The Great Miami River Watershed: Environmental Isotope Approach, Rachel Kristine Buzeta Apr 2019

Nitrate Contaminant Tracing In Surface And Groundwater In The Great Miami River Watershed: Environmental Isotope Approach, Rachel Kristine Buzeta

Honors Theses

The global population has increased exponentially causing several challenges surrounding sustainability, including greater food production needs. To meet these demands and boost agricultural productivity, more efficient practices and fertilizers are used. Synthetic fertilizers and other nutrient sources have resulted in water quality degradation and pollution. Much of the Great Miami River Watershed’s streams and aquifers in southwestern Ohio are affected by nitrate contaminants originating from anthropogenic sources including synthetic and organic fertilizer used for agriculture, human wastes (domestic, industrial, and municipal wastes), and urbanization. High nitrate concentrations cause ecological disturbances across all trophic levels. Nitrate levels greater than 10 mg/L …


Endolithic Microbial Carbon Cycling In East Antarctica, Natalie Tyler Apr 2019

Endolithic Microbial Carbon Cycling In East Antarctica, Natalie Tyler

Theses and Dissertations

Microbes adapt to inhospitable conditions by colonizing niches that protect them from severe environmental conditions, making them model organisms in the search for life on other planets. Endoliths are globally ubiquitous microbes that colonize structural cavities within rocks, which protect them from environmental stressors while maintaining access to nutrition and light sources. Despite harsh katabatic winds, extreme temperature fluctuations, harmful UV radiation and exposure to desiccation, endolithic communities have been observed in Antarctica. Previous studies have found viable and abundant microbial biomass through microscopy and the addition of isotopic labels. However, due to the slow metabolic activity of these microbes, …


High-Resolution Investigation Of Event Driven Sedimentation: Response And Evolution Of The Deepwater Horizon Blowout In The Sedimentary System, Rebekka A. Larson Apr 2019

High-Resolution Investigation Of Event Driven Sedimentation: Response And Evolution Of The Deepwater Horizon Blowout In The Sedimentary System, Rebekka A. Larson

USF Tampa Graduate Theses and Dissertations

This Dissertation combines the investigation of the sedimentological impacts of the Deepwater Horizon (DwH) blowout event in the deep-sea benthos, with the refinement and advancement of methods and approaches for high-resolution investigations of events preserved in sedimentary records. An approach that combined, rapid collection of cores, a continued annual time series collection of cores, and high-resolution sampling and analyses, in particular short-lived Radioisotopes (SLRad), enabled the temporal resolution required to detect the sedimentary response to the short-duration DwH event, and evaluate post-event sedimentation patterns at a comparable time scale (months).

The collection of 179 sediment cores from 80 sites between …


A New Chronostratigraphic Framework For The Silurian (Wenlockian) Niagara And Salina Units Of The Michigan Basin, Matthew Rine Apr 2019

A New Chronostratigraphic Framework For The Silurian (Wenlockian) Niagara And Salina Units Of The Michigan Basin, Matthew Rine

Dissertations

Constraining the ages of sedimentary strata is challenging and is the principle source of stratigraphic uncertainty in sedimentary basins worldwide. The story is no different in the Michigan Basin, where our current understanding of the Silurian Niagara-Lower Salina stratigraphic record is based in large part on limited sedimentological and chronological data, resulting in a collection of models that disagree about the timing of deposition. This disagreement marks the starting point for the dissertation research presented here. The studies included in the dissertation integrate conventional and novel approaches to address the stratigraphic uncertainty that has plagued Silurian reef researchers for decades. …


Developing Early Warning Systems For Debris Flows And Harmful Algal Blooms, Sita Karki Apr 2019

Developing Early Warning Systems For Debris Flows And Harmful Algal Blooms, Sita Karki

Dissertations

This study focused on developing early warning systems for two types of geohazards using methods that heavily rely on remote sensing data. The first investigation attempted to develop a prototype version of an early warning system for landslide development, whereas the second focused on harmful algal bloom prediction.

Construction of intensity-duration (ID) thresholds, and early warning and nowcasting systems for landslides (EWNSL) are hampered by the paucity of temporal and spatial archival data. This work represents significant steps towards the development of prototype EWNSL to forecast and nowcast landslides over Faifa Mountains in the Red Sea Hills. The developed methodologies …


Suspended Sediment Transport Revealed By Patterns In Turbidity And Electrical Conductivity Curves In Three Cave Systems In Missouri, Usa., Caroline M. Mierzejewski Mar 2019

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 …


Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin Thomas Lynch, Douglas R. Leasure, Daniel D. Magoulick Mar 2019

Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin Thomas Lynch, Douglas R. Leasure, Daniel D. Magoulick

United States Geological Survey: Staff Publications

We examined flowalteration-ecology relationships in benthic macroinvertebrate, fish, and crayfish assemblages in Ozark Highland streams, USA, over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013). We hypothesized that: 1) there would be temporal variation in flow alteration-ecology relationships between the two years, 2) flow alteration-ecology relationshipswould be stronger during the drought year vs the flood year, and 3) fish assemblages would show the strongest relationships with flow alteration. We used a quantitative richest-targeted habitat (RTH) method and a qualitative multihabitat (QMH) method to collect macroinvertebrates at 16 USGS gaged sites during both years. …


Nitrogen And Phosphorus Uptake In An Urban Stream Ecosystem, Nicolette A. Sheffield Mar 2019

Nitrogen And Phosphorus Uptake In An Urban Stream Ecosystem, Nicolette A. Sheffield

Theses and Dissertations

Urban stream ecosystems are faced with high input levels of nitrogen (N) and phosphorus (P) from anthropogenic activities. N and P are important to plant growth and stream health; however, high levels can lead to algal blooms and eutrophication, a harmful effect to both aquatic life and water quality. Common urban sources of N and P include fertilizer, atmospheric deposition, stormwater outfall, and leaf-litter decomposition. Common urban stream features such as a flashier hydrograph, altered channel stability and morphology, increase in nutrient output (such as N and P), and heat retention, have been shown to result in an overall decrease …


Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin T. Lynch, Douglas R. Easure, Daniel D. Magoulick Mar 2019

Flow Alteration-Ecology Relationships In Ozark Highland Streams: Consequences For Fish, Crayfish And Macroinvertebrate Assemblages, Dustin T. Lynch, Douglas R. Easure, Daniel D. Magoulick

United States Geological Survey: Staff Publications

We examined flowalteration-ecology relationships in benthic macroinvertebrate, fish, and crayfish assemblages in Ozark Highland streams, USA, over two years with contrasting environmental conditions, a drought year (2012) and a flood year (2013). We hypothesized that: 1) there would be temporal variation in flow alteration-ecology relationships between the two years, 2) flow alteration-ecology relationshipswould be stronger during the drought year vs the flood year, and 3) fish assemblages would show the strongest relationships with flow alteration. We used a quantitative richest-targeted habitat (RTH) method and a qualitative multihabitat (QMH) method to collect macroinvertebrates at 16 USGS gaged sites during both years. …


Variations Of Sedimentary Biogenic Silica In The Gulf Of Mexico During The Deepwater Horizon And Ixtoc-I Oil Spill., Jong Jin Lee Mar 2019

Variations Of Sedimentary Biogenic Silica In The Gulf Of Mexico During The Deepwater Horizon And Ixtoc-I Oil Spill., Jong Jin Lee

USF Tampa Graduate Theses and Dissertations

The goal of this research is to understand the impacts of the 2010 Deepwater Horizon oil spill and the 1970-1980 IXTOC-I oil spill and other anthropogenic activity (e.g. dam construction) on surface water primary productivity by measuring sedimentary biogenic silica. It is known that sedimentary biogenic silica is distinct from mineral – bound silica, therefore it has been used as a proxy record for surface water primary productivity (e.g. diatom blooms). The Deepwater Horizon oil spill resulted in a widespread Marine Oil Snow Sedimentation and Flocculent Accumulation (MOSSFA) event. The IXTOC-I oil spill was one of the largest oil spills …


Exploring Geochemical Proxies For Identifying Cryptic Sequence Boundaries In The Geologic Past Using Modern Bahamian Analogues, Evan B. Magette Mar 2019

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. …


Seismic Landslide Hazard Mapping For Greater Vancouver, British Columbia, Ali Fallah Yeznabad, Sheri E. Molnar, Hesham M. El Naggar Mar 2019

Seismic Landslide Hazard Mapping For Greater Vancouver, British Columbia, Ali Fallah Yeznabad, Sheri E. Molnar, Hesham M. El Naggar

Western Research Forum

The lower Mainland of southwest British Columbia (BC) hosts about 3.5 million people and significant infrastructures of national importance. Southwestern BC has the highest seismic risk in Canada with significant potential to cause earthquake-induced hazards including tsunamis, liquefaction and landslides. A Cascadia mega-thrust (MW 9) earthquake is predicted to generate $75 billion Canadian dollars in losses. This damage can be resulted from ground shaking or its secondary phenomena like landslides; ground shaking during earthquakes may trigger landslides that can damage or destroy buildings, bury roads and highways and kill and injure people. In Canada, during the past century and …


Nitrate Concentrations In Streams As A Function Of Crop Cover In Midwestern Agricultural Watersheds: Assessing The Role Of Corn And Soybeans, Jacob Tyler Piske Mar 2019

Nitrate Concentrations In Streams As A Function Of Crop Cover In Midwestern Agricultural Watersheds: Assessing The Role Of Corn And Soybeans, Jacob Tyler Piske

Theses and Dissertations

Increased availability and reduced cost of synthetic-nitrogen fertilizers have led to excess nitrogen being deposited in reservoirs. The accumulation of nitrogen (N) in reservoirs has negative effects, generating algal blooms, hypoxic zones, and poor drinking water quality. Corn and soybean utilize nitrogen at different rates, resulting in higher nitrogen fertilizer application to fields for corn than for soybean. This work examines whether the nitrate concentration in a stream may be correlated to the percentage of land devoted to growing corn or soybeans in the watershed. To investigate potential relationships, discharge (Q) and nitrate concentration data from ten USGS gauging stations …


Assessing Paleo-Coastal Caves Evolution And Sea Level Changes In Mallorca: Results From Radiometric Dating Of Speleothems, Giuseppe Lucia Mar 2019

Assessing Paleo-Coastal Caves Evolution And Sea Level Changes In Mallorca: Results From Radiometric Dating Of Speleothems, Giuseppe Lucia

USF Tampa Graduate Theses and Dissertations

Sea level affects the littoral morphology and structure in different ways. In coastal karst basins, dissolutional and depositional processes are strictly related to sea level variation. A great variety of karst-related geomorphological features and cave deposits exist above, below, and at sea level, and are extremely useful to study past changes of relative sea level. Within these, vadose speleothems such as flowstones and stalagmite, can document unequivocal maximum sea level constraints as well as record phreatic phases of sea level rise. Here we present a series of geochronological data from the eastern Mallorca and show the implication of relative sea …


Examining The Spatial And Temporal Variations In Co2 Partial Pressure In The Deep Vadose Zone Above Jinapsan Cave, Guam, Jamar Regis Mar 2019

Examining The Spatial And Temporal Variations In Co2 Partial Pressure In The Deep Vadose Zone Above Jinapsan Cave, Guam, Jamar Regis

USF Tampa Graduate Theses and Dissertations

Carbon dioxide is the primary driver of dissolution and precipitation reactions in epigene limestone caves. While much work has been conducted on CO2 dynamics involved in dissolution in the phreatic zone, less research has been conducted on vadose CO2 dynamics, especially in tropical caves developed in eogenetic limestones. In this study, we investigate spatial and temporal variation in pCO2 in the deep vadose zone of eogenetic limestone above Jinapsan Cave, located in northern Guam. Five years of carbonate chemistry data from three dripwater sites in Jinapsan Cave (Flatman, Station1, and Trinity) were used to model the theoretical pCO2 with which …


Volcanic Stratigraphy And Age Model Of The Kimama Deep Borehole (Project Hotspot): Evidence For 5.8 Million Years Of Continuous Basalt Volcanism, Central Snake River Plain, Idaho, Katherine E. Potter, Duane E. Champion, Robert A. Duncan, John W. Shervais Mar 2019

Volcanic Stratigraphy And Age Model Of The Kimama Deep Borehole (Project Hotspot): Evidence For 5.8 Million Years Of Continuous Basalt Volcanism, Central Snake River Plain, Idaho, Katherine E. Potter, Duane E. Champion, Robert A. Duncan, John W. Shervais

Geosciences Faculty Publications

The Snake River Plain of central Idaho represents the world’s best example of a mantle hotspot track impinging upon continental crust and provides a record of bimodal volcanism extending over 12 Ma to the present. Project Hotspot recovered almost 2 km of continuous drill core from the Kimama borehole, located in central Idaho on the axial volcanic zone. The Kimama drill core represents the most complete record of mafic volcanism along the Yellowstone–Snake River Plain hotspot track.

A total of 432 basalt flow units, representing 183 basalt flows, 78 basalt flow groups, and 34 super groups, along with 42 sediment …


Modeled Affinity Constants For Phosphorus Adsorption And Desorption Due To Saltwater Intrusion, Yasemin Taşcı Mar 2019

Modeled Affinity Constants For Phosphorus Adsorption And Desorption Due To Saltwater Intrusion, Yasemin Taşcı

USF Tampa Graduate Theses and Dissertations

It is important to understand the processes that regulate phosphorus (P) fluxes to coastal environments, because P is an important nutrient in coastal ecosystems. Phosphorus adsorbs to the surface of minerals in sediment and bedrock, and an influx of seawater can cause some of that P to desorb, raising the P concentration of ambient water. Although seawater-induced P desorption is thought to be an important source of P to coastal environments, the chemical reactions that underlie it have not been established. Previous work provides some relevant surface reactions and associated affinity constants between various aqueous P species and the surface …


The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory Mar 2019

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 Mar 2019

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, …


Pleistocene Glacial History Of The New Zealand Subantarctic Islands, Eleanor Rainsley, Chris S.M. Turney, Nicholas R. Golledge, Janet M. Wilmshurst, Matt S. Mcglone, Alan G. Hogg, Bo Li, Zoë A. Thomas, Richard Roberts, Richard T. Jones, Jonathan G. Palmer, Verity Flett, Gregory De Wet, David K. Hutchinson, Mathew J. Lipson, Pavla Fenwick, Ben Hines, Umberto Binetti, Christopher J. Fogwill Mar 2019

Pleistocene Glacial History Of The New Zealand Subantarctic Islands, Eleanor Rainsley, Chris S.M. Turney, Nicholas R. Golledge, Janet M. Wilmshurst, Matt S. Mcglone, Alan G. Hogg, Bo Li, Zoë A. Thomas, Richard Roberts, Richard T. Jones, Jonathan G. Palmer, Verity Flett, Gregory De Wet, David K. Hutchinson, Mathew J. Lipson, Pavla Fenwick, Ben Hines, Umberto Binetti, Christopher J. Fogwill

Geosciences: Faculty Publications

The New Zealand subantarctic islands of Auckland and Campbell, situated between the subtropical front and the Antarctic Convergence in the Pacific sector of the Southern Ocean, provide valuable terrestrial records from a globally important climatic region. Whilst the islands show clear evidence of past glaciation, the timing and mechanisms behind Pleistocene environmental and climate changes remain uncertain. Here we present a multidisciplinary study of the islands-including marine and terrestrial geomorphological surveys, extensive analyses of sedimentary sequences, a comprehensive dating programme, and glacier flow line modelling-to investigate multiple phases of glaciation across the islands. We find evidence that the Auckland Islands …