Digital Commons Network^™

Techniques And Algorithms For Immersive And Interactive Visualization Of Large Datasets, Ashish Sharma

LSU Master's Theses

Advances in computing power have made it possible for scientists to perform atomistic simulations of material systems that range in size, from a few hundred thousand atoms to one billion atoms. An immersive and interactive walkthrough of such datasets is an ideal method for exploring and understanding the complex material processes in these simulations. However rendering such large datasets at interactive frame rates is a major challenge. A scalable visualization platform is developed that is scalable and allows interactive exploration in an immersive, virtual environment. The system uses an octree based data management system that forms the core of the …

Lithium Isotope Geochemistry Of Marine Sediments., Libo Zhang

LSU Historical Dissertations and Theses

While the isotope geochemistry of lithium in the marine environment is increasingly known, there are still outstanding problems concerning its oceanic budget and mantle-crust recycling that remain to be resolved. To evaluate the role of marine sediments in the oceanic budget, laboratory experiments were conducted to determine the extent of lithium adsorption on marine sediments and the magnitude of isotopic fractionation. Sediments from the Greenland margin were studied to gain further understanding of the sediment-water interaction. The isotopic compositions of the major types of marine sediments were characterized to understand the sedimentary cycle of lithium. The enhanced database permits a …

Pliocene And Pleistocene Marine Ostracoda Of The Limon Basin, Costa Rica: A Record Of Paleoenvironmental Change., Pamela Frances Borne

LSU Historical Dissertations and Theses

Late Pliocene (3.8-3.6 Ma) and early Pleistocene (1.5-0.9 Ma) marine ostracodes of the Rio Banano, Quebrada Chocolate and Moin Formations (Limon Group) provide a detailed paleoenvironmental record for the Limon Basin, Costa Rica. The marine ostracode assemblages recovered from the Limon region do not provide evidence that the tropics cooled dramatically during the late Pliocene when the Northern Hemisphere was entering the Modern Ice Age. Paleoenvironmental interpretations are based on cluster analyses and a modern tropical ostracode analog analysis. Diverse ostracode assemblages of the middle Pliocene Rio Banano Formation are dominated by genera typical of the inner to middle neritic …

Some Effects Of 30 Years Of Weir-Management On Coastal Marsh Aquatic Vegetation And Implications To Waterfowl Management, John A. Nyman, Robert H. Chabreck

Faculty Publications

Aquatic vegetation was compared between weir-managed and unmanaged brackish marsh ponds at Marsh Island, Louisiana, parts of which have been weir-managed since 1958. Coverage by aquatic vegetation was greater in weir-managed ponds than in unmanaged ponds, but weir-management affected individual species differently. Eleocharis parvula was more common in unmanaged ponds than in managed ponds during the early 1960s but has not occurred in any ponds sampled since then. Ceratophyllum demersum and the dominant plants Myriophyllum spicatum and Ruppia maritima were more common in weir-managed ponds than in unmanaged ponds, although the magnitude of the difference varied greatly among sample dates. …

Tectonic Implications Of Fission-Track Thermochronology And Amphibole Thermobarometry Studies Of The Northern Peninsular Ranges Batholith, Southern California., Peter Gillham George

LSU Historical Dissertations and Theses

Fission-track data from the San Jacinto Mountains and the Palomar Mountain-Escondido study area indicate that the Late Cretaceous history of the Peninsular Ranges batholith is marked by a series of major cooling events. Coupled with geobarometry measurements and field observations, these data allow for a greater understanding of the nature and timing of both local and regional tectonic events. In the eastern Peninsular Ranges, west-vergent thrusting along the Santa Rosa mylonite belt at $\sim$99-94 Ma was followed by major extensional faulting between $\sim$94 and 92 Ma. Amphibole geobarometry of mylonites indicate that $\sim$10-18 km of crustal thickening occurred as a …

Geology And Volcanology Of The Recent Evolution Of Galeras Volcano, Colombia, Marta Lucía Calvache

LSU Historical Dissertations and Theses

Galeras volcano is located in southwestern Colombia, rising 1600 m above Pasto the capital city (population of 300,000) of the department of Nariño. The most recent activity at Galeras volcano(< 4500 years) included six major eruptions before the reactivation of 1988-present. The activity at the volcano has been characterizated by eruptions of vulcanian type. Gravitational column collapse is the most common origin of the fines-depleted co-ignimbrite breccias and pyroclastic flows. Commonly, a large part of the material ejected with each explosion is not juvenile but includes country rock as accessory lithics. In the initial explosions at Galeras, the country rock appear to be more involved that any other material. Later in the eruption, the products become more juvenile-rich deposits. The total volume of deposits related to Galeras volcano has been calculated to be 0.71 km³

Galeras volcano has had a fairly constant chemical composition, characterized by high silica, medium potassium andesites. Products at Galeras are mainly composed of zoned plagioclase, hypersthene, augite, titanomagnetite, ilmenite and traces of apatite. Amphibole and olivine may be also present. A shallow, small magma ( « 0.5 km³) chamber is consistent with the data for Galeras Volcano. The magmatic conditions in this reservoir prior to eruptions have …

Neogene Basin Evolution In The Southwestern Dominican Republic: A Foraminiferal Study., Peter Paul Mclaughlin Jr

LSU Historical Dissertations and Theses

The Azua Basin sequence is a 2500 m thick Miocene Pliocene regressive interval. Limestones and marls of the Sombrerito Formation, the lowermost unit, ranges from lower Miocene to lowermost upper Miocene. The turbidite sequence of the Trinchera Formation spans an interval from uppermost middle Miocene to lower Pliocene. Blue-green, neritic lower Pliocene siltstones of the Quita Coraza Formation overlie the Trinchera in the seaward part of the basin. Shallow-marine strata in the lower part of the Arroyo Blanco Formation range from uppermost Miocene to middle Pliocene. Principal Components Analysis of rich benthic foraminiferal faunas aided in the recognition of species …

Modeling Wetland Loss In Coastal Louisiana: Geology, Geography, And Human Modifications, James H. Cowan Jr., R. Eugene Turner

Faculty Publications

Habitat change in coastal Louisiana from 1955/6 to 1978 was analyzed to determine the influence of geological and man-made changes on landscape patterns within 7.5 min quadrangle maps. Three quantitative analyses were used: principal components analysis, multiple regression analysis, and cluster analysis.

Regional differences in land loss rates reflect variations in geology and the deltaic growth/decay cycles, man-induced changes in hydrology (principally canal dredging and spoil banking), and land-use changes (principally urbanization and agricultural expansion). The coastal zone is not homogeneous with respect to these variables and the interaction between causal factors leading to wetland loss is therefore locally variable …

Backfilling Canals To Mitigate Wetland Dredging In Louisiana Coastal Marshes, Christopher Neill, R. Eugene Turner

Faculty Publications

Returning canal spoil banks into canals, or backfilling, is used in Louisiana marshes to mitigate damage caused by dredging for oil and gas extraction. We evaluated 33 canals backfilled through July 1984 to assess the success of habitat restoration. We determined restoration success by examining canal depth, vegetation recolonization, and regraded spoil bank soils after backfilling. Restoration success depended on: marsh type, canal location, canal age, marsh soil characteristics, the presence or absence of a plug at the canal mouth, whether mitigation was on- or off-site, and dredge operator performance.

Backfilling reduced median canal depth from 2.4 to 1.1 m, …

Coastal Louisiana Recent Land Loss And Canal Impacts, William W. Scaife, R. Eugune Turner, Robert Constanza

Faculty Publications

Annual coastal land loss in the sedimentary deltaic plain of southern Louisiana is 102 km2, which is correlated with man-made canal surface area. The relationships between land loss and canals are both direct and indirect and are modified by the deltaic substrate, distance to the coast, and availability of new sediments. Loss rates are highest in the youngest of the former deltas nearest the coast; they are lowest in the more consolidated sediments far from the coast. The average estimate for land loss at zero canal density in the six regression equations developed was 0.09%±0.13% annually, the present land loss …

Land Loss In Coastal Louisiana (U.S.A.), N. J. Craig, R. Eugene Turner, J. W. Day Jr.

Faculty Publications

This paper examines causes and consequences of wetland losses in coastal Louisiana. Land loss is a cumulative impact, the result of many impacts both natural and artificial. Natural losses are caused by subsidence, decay of abandoned river deltas, waves, and storms. Artificial losses result from flood-control practices, impoundments, and dredging and subsequent erosion of artificial channels. Wetland loss also results from spoil disposal upon wetlands and land reclamation projects.

Total land loss in Louisiana's coastal zone is at least 4,300 ha/year. Some wetlands are converted to spoil banks and other eco-systems so that wetland losses are probably two to three …

Occupation Sequence At Avery Island., Sherwood Moneer Gagliano

LSU Historical Dissertations and Theses

No abstract provided.

A Biogeographical Investigation Of The Sierra De Tuxtla In Veracruz, Mexico., Robert F. Andrle

LSU Historical Dissertations and Theses

No abstract provided.

Cenozoic Cyclic Deposition In The Subsurface Of Central Louisiana., Louis H. Dixon

LSU Historical Dissertations and Theses

No abstract provided.

Distribution And Engineering Significance Of Sediments Bordering The Mississippi From Donaldsonville To The Gulf., Charles Rudolph Kolb

LSU Historical Dissertations and Theses

No abstract provided.

The Spotted Horse Coal Field, Sheridan And Campbell Counties, Wyoming., Wilds W. Olive

LSU Historical Dissertations and Theses

No abstract provided.