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Articles 301 - 330 of 423
Full-Text Articles in Earth Sciences
Geomicrobiology Of Louisiana Coastal Marshes Before And After The Deepwater Horizon Oil Spill, Chang Liu
Geomicrobiology Of Louisiana Coastal Marshes Before And After The Deepwater Horizon Oil Spill, Chang Liu
LSU Master's Theses
The 2010 Deepwater Horizon oil spill in the Gulf of Mexico not only impacted open ocean and shoreline geochemical and ecological environments, but it served to promote research of microbial ecosystems in poorly studied habitats, such as Louisiana marshes. Sediment and water samples from four main marshes in southern Louisiana were collected in May 2010 (pre-oil), September 2010 (oiled), and June 2011 (post-oil). Sites near the Mississippi River had exceptionally low salinity in the immediate months following the oil spill due to freshwater diversion efforts; salinity increased by an order of magnitude one year later. Microbial diversity was evaluated from …
Miscible Column Studies Of Unfractured And Saturated Cores Of Topopah Spring Tuff From Yucca Mountain, Nevada Using Hydrophobic Organic Pollutants, Kody V. Kramer
LSU Master's Theses
Miscible displacement column studies were conducted on unfractured cores of Topopah Spring Tuff to quantify transport characteristics of bromide&44; pentafluorobenzoic acid &40;PFBA&41;&44; trichloroethylene &40;TCE&41;&44; and naphthalene. Three 5 cm diameter by 2 cm long cores were flushed with pulses of simulated groundwater containing these tracers&44; followed by tracer&45;free solution. Effective porosities were gravimetrically measured as 11&37;&44; 10.6&37;&44; and 9.5&37;. The tracers achieved full breakthrough in an order correlating to their hydrophobicities. Bromide and PFBA sorbed least&44; achieving full breakthrough in fewer than 10 pore volumes. As water analogues&44; both exhibited no quantifiable sorption. Delay to full breakthrough was contributed to …
Investigation Into The Cause Of Earthen Embankment Instability Along The "V-Line" Artificial Levee In Marrero, Louisiana, Usa, Jason Hicks
LSU Master's Theses
The “V-line” levee, located in Marrero, LA, has a crack along its crest, measuring approximately 100 meters in length, 30 centimeters in depth, and 30 centimeters in width. This crack is a sign of levee instability. Seismic shear wave, CPT, and laboratory shear strength data were collected and processed to identify the cause of the instability. A zone of low seismic shear wave velocity was interpreted approximately 3 meters deep from the berm of the levee. Because of the large spacing between laboratory shear strength test sampling and CPT sites, a similar zone of low shear strength was not found …
Non-Mass Dependent Isotope Fractionation: An Application In The Hyperarid Environment And A Set Of Experiments On Thermal Diffusion, Tao Sun
LSU Doctoral Dissertations
This dissertation consists of two independent topics; both are related to non-mass dependent isotope fractionation. 1) Atacama Gravel Sulfate: The onset of hyperaridity of Atacama Desert is of geological importance and has been controversial. I put constraints this timing by looking into a new record, a deep sulfate profile extending from the surface down to the oxide zone of a copper ore in the Atacama Gravels, whose deposition covers a majority of the Central Depression and temporarily spans from semi-arid to hyper-arid climate. The gravel sulfates show a strong depth-dependent pattern through ~50 meters (15 to 65 meter depth): narrow …
Stories Of The Proterozoic Earth: Paleoproterozoic Chuanlinggou Arcitarchs And Neoproterozoic ¹⁷O-Depleted Barite, Yongbo Peng
Stories Of The Proterozoic Earth: Paleoproterozoic Chuanlinggou Arcitarchs And Neoproterozoic ¹⁷O-Depleted Barite, Yongbo Peng
LSU Doctoral Dissertations
This dissertation consists of two independent topics, both critical to understanding Earth history during the Proterozoic Eon. (1) Paleoproterozoic Chuanlinggou Acritarchs: The eukaryotic affinity of acritarchs from the Chuanlinggou Formation has been questioned because of lack of indisputable morphological evidence. In this study, Chuanlinggou acritarchs were examined by jointly using optical microscopy, scanning electron microscopy, and transmission electron microscopy. In most cases, an ovoidal group of acritarchs represents a half-vesicle following a complete longitudinal rupture, which is a morphological model different from a whole envelope with medial splits, as proposed by earlier studies. This ovoidal group displays a bipolar morphology, …
Rare Earth Elements As An Investigative Tool Into The Source, Age, And Ecology Of Late Miocene To Late Pleistocene Fossils From The Tunica Hills, Louisiana, Lindsey Theresa Yann
Rare Earth Elements As An Investigative Tool Into The Source, Age, And Ecology Of Late Miocene To Late Pleistocene Fossils From The Tunica Hills, Louisiana, Lindsey Theresa Yann
LSU Master's Theses
Rare earth elements were investigated for their potential to determine provenance and depositional environments of vertebrate fossils found as float in creeks of the Tunica Hills region of Louisiana. Elemental analyses are used to test the hypotheses that fossils span multiple time periods, from late Miocene to late Pleistocene, and that elemental profiles can distinguish terrestrial depositional settings from possible estuarine deposits. In addition, the animals present were then used to test the hypothesis that Tunica Hills had late Pleistocene environmental conditions much like the modern Great Lakes region. This study is important because it provides new insight on the …
A Functional And Ontogenetic Skull Analysis Of The Extant Rhinoceroses And Teleoceras Major, An Extinct Miocene North American Rhinoceros, Mark Daniel Hagge
A Functional And Ontogenetic Skull Analysis Of The Extant Rhinoceroses And Teleoceras Major, An Extinct Miocene North American Rhinoceros, Mark Daniel Hagge
LSU Master's Theses
Functional and ontogenetic skull differences among extant rhinoceroses and the extinct North American rhinoceros Teleoceras major were investigated to assess the unknown feeding ecology of Teleoceras. Ontogenetic skull sequences of the extant Indian rhino (Rhinoceros unicornis), Sumatran rhino (Dicerorhinus sumatrensis), white rhino (Ceratotherium simum), and black rhino (Diceros bicornis), and the extinct Miocene North American rhino T. major were gathered for both qualitative and quantitative assessments. Eleven functional characters related to specific feeding ecologies in extant perissodactyls were morphologically described, and each species’ skull development was described in detail. Nineteen linear skull measurements were taken across all specimens of all …
Salinity Variation As An Indicator Of Fluid Flow In The Lower Ellesmerian Sequence, North Slope, Alaska, Jacob Scott Dehamer
Salinity Variation As An Indicator Of Fluid Flow In The Lower Ellesmerian Sequence, North Slope, Alaska, Jacob Scott Dehamer
LSU Master's Theses
Previous studies have shown the existence of a topographically driven recharge system in the North Slope foreland basin, Alaska. The Lower Ellesmerian Sequence represents the lowest most flow pathway in the stratigraphic sequence. Limestones and dolomites of the Lisburne Group and sands and shales of the Endicott Group represent laterally extensive pathways for flow. Salinities calculated from spontaneous potential response in the Lower Ellesmerian range from less than 10 gL-1 to over 150 gL-1. Low salinities calculated for the Lower Ellesmerian indicate the displacement of connate marine waters throughout the history of the North Slope foreland basin. Flushing of connate …
Miocene Fluctuations Of The West Antarctic Ice Sheet And The Influence Of Meltwater On The Ross Sea Outer Continental Shelf: Seismic-Stratigraphic Based Interpretations, Sean Francis Kerrin
Miocene Fluctuations Of The West Antarctic Ice Sheet And The Influence Of Meltwater On The Ross Sea Outer Continental Shelf: Seismic-Stratigraphic Based Interpretations, Sean Francis Kerrin
LSU Master's Theses
The changing extents of the West Antarctic Ice Sheet (WAIS) and the manifestation of meltwater discharge on the outer shelf during the Miocene were deduced using seismic stratigraphy and seismic facies interpretations. Deep Sea Drilling Project (DSDP) Leg 28 drill sites were used for chronologic constraints of the outer continental shelf (OCS) seismic stratigraphy to establish correlations to coeval strata at the inner shelf SMS-ANDRIL drill site. The evidence indicates that grounded ice sheets periodically existed on the OCS during the early and middle Miocene and in section inferred to have been deposited in the late-Miocene. Large-scale grounding events occurred …
A Petrophysical Evaluation Of Factors That Control Cap Rock Seal Quality, Andrew Tyler Harrison
A Petrophysical Evaluation Of Factors That Control Cap Rock Seal Quality, Andrew Tyler Harrison
LSU Master's Theses
Textural and mineralogical variations within 33 shale samples were analyzed to provide a model for predication of hydrocarbon top-seal efficiency. Variation in mineral abundances in the subsurface influences petrophysical properties and other characteristics of hydrocarbon sealing sequences and reservoirs. In geophysical well logs, various proxies, such as gamma ray emission and neutron absorption, are used to assess changes in mineral composition. This study directly compares X-ray diffraction measurements of mineral percentages and geophysical responses from Middle Miocene cored intervals in the Santa Cruz Well; Mississippi Canyon block 519, Gulf of Mexico with those derived from well logging. Distinct textural differences …
Spatial Variations Of Salinity, Temperature And Pressure On The Flank Of A Salt Dome, Offshore Louisiana: Implications For Mechanisms Of Fluid Flow, Andrew Kevin Steen
Spatial Variations Of Salinity, Temperature And Pressure On The Flank Of A Salt Dome, Offshore Louisiana: Implications For Mechanisms Of Fluid Flow, Andrew Kevin Steen
LSU Master's Theses
Salt dome dissolution in the Gulf of Mexico sedimentary basin is a primary cause for elevated pore water salinities in the subsurface. Temperature, pressure, salinity, lithology and fluid density are parameters often used to identify preferential conduits and driving forces for fluid migration. These parameters were calculated using 20 wireline logs covering 40 km² on the south flank of a salt dome on the continental shelf, offshore Louisiana. 3-D seismic has been utilized to determine location of faults, to aid in sand correlation, and to provide a structural overview of the dome. Vertical and lateral variations in lithology, salinity, temperature, …
Taphonomy And Sedimentology Of Two Miocene Vertebrate Fossil Sites On Fort Polk, Louisiana, Julie Lynn Hill
Taphonomy And Sedimentology Of Two Miocene Vertebrate Fossil Sites On Fort Polk, Louisiana, Julie Lynn Hill
LSU Master's Theses
The discovery of a terrestrial mammalian fauna in the Miocene deposits on Fort Polk, Louisiana, fills a geographic gap in the Gulf Coast paleontological framework, but the provenance of the fossils, nature of the depositional environments, and relationships between the sites is still debated. This is especially true for the TVOR site cluster. TVOR SE has a mixture of marine and terrestrial vertebrates in association with a partly dissolved, in situ bed of articulated oyster shells, which stands in contrast to the fully terrestrial and freshwater assemblage at TVOR, and the indeterminate site TVOR S. Although limited outcrop may bias …
Palynological Analysis Of Tiger And Trinity Shoals, Louisiana Continental Shelf, Russell Ryan Crouch
Palynological Analysis Of Tiger And Trinity Shoals, Louisiana Continental Shelf, Russell Ryan Crouch
LSU Master's Theses
Forty sediment samples taken from twenty-six vibracores collected from Holocene shoals (Tiger and Trinity) were processed for palynomorphs and analyzed to characterize the terrestrial and marine paleo-environments of southern Louisiana at the time of deposition of each shoal. Abundant and diverse pollen assemblages were recovered while marine microplankton were sparse (< 2% relative abundance). Pollen species were grouped by plants of similar environmental significances including arboreal, non-arboreal, aquatic, and shrub categories. Palynological signals were compared in detail between each core, as well as along strike and dip transects, to help determine whether or not these shoals were deposited coevally or in distinct depositional cycles. Evidence shows that Tiger and Trinity Shoals carry remarkably similar palynological profiles, indicating that sediments of these shoals areS from the same source, and that deposition extended over an interval of time such that climate change was not sufficient enough to alter the vegetation response (hence palynological signal). Pollen profiles show source sediments are predominantly from the lower Mississippi River drainage basin and exhibit species similar to those present in modern Louisiana coastal marshes and swamps (i.e., Taxodium distichum, Cyperaceae, Graminae, Chenopodiaceae, and Asteraceae), and coastal to upland hardwood forests of the Mississippi River alluvial valley (i.e., Pinus, Quercus, Carya, and Liquidambar styraciflua).
Delineation Of A Produced Water Plume In Pointe Coupee Parish, Louisiana, Matthew C. Smith
Delineation Of A Produced Water Plume In Pointe Coupee Parish, Louisiana, Matthew C. Smith
LSU Master's Theses
Three pits were excavated in the 1960’s at the Fordoche Oil Field in Lottie, Louisiana, as evaporation pits for oil well produced brines. The pits were closed and completed in the 1980’s. Previous studies indicate that produced water has leached into the subsurface within the area to the south and southeast of the pits. Ground penetrating radar (GPR) was utilized in an attempt to delineate the present location of the plume as well as test the feasibility of GPR within a clayey soil in south Louisiana. In addition to collection of GPR data, electrical conductivity logs and soil cores (including …
Using Inoceramid Bivalve Taphonomy As A Paleoenvironmental Indicator Across The Cenomanian/Turonian Horizon At The Pueblo, Colorado Gssp, Jacob Frederick Grosskopf
Using Inoceramid Bivalve Taphonomy As A Paleoenvironmental Indicator Across The Cenomanian/Turonian Horizon At The Pueblo, Colorado Gssp, Jacob Frederick Grosskopf
LSU Master's Theses
Recent paleoenvironmental and geochemical studies indicate that benthic conditions during Oceanic Anoxic Event II (OAE II) (93.5 Mya) in the Cretaceous Interior Seaway (CIS) were dysoxic rather than anoxic. In this thesis, dysoxic benthic conditions were tested for by observing patterns in taphonomic alteration of the calcite portions of inoceramid bivalve shells during and after OAE II. Inoceramid valves were extracted from beds that spanned OAE II at the Cenomanian/Turonian Global Boundary Stratotype Section and Point (GSSP) in Pueblo, Colorado: beds 62 (Hartland Shale), 72 (Bridge Creek Limestone), and 115 (Bridge Creek Limestone). Degree of alteration was tallied using categorical …
Geothermal Resource Assessment Of The Gueydan Salt Dome And The Adjacent Southeast Gueydan Field, Vermilion Parish, Louisiana, Taylor Austin Gray
Geothermal Resource Assessment Of The Gueydan Salt Dome And The Adjacent Southeast Gueydan Field, Vermilion Parish, Louisiana, Taylor Austin Gray
LSU Master's Theses
The fluids heated by the high thermal conductivity and vertical geometry of salt domes in South Louisiana have the potential to be an economic source of geothermal energy. The Gueydan dome is a piercement salt diapir in Southwest Louisiana lying along the Vermilion and Acadia Parish border. Isotherms indicate a thermal anomaly at the crest of the dome with formation temperatures of 62 ˚C recorded at 1346 m, which is too cold for a geothermal prospect. The shallowest salt encountered is at a depth of 1475 m, and the surrounding strata are Cenozoic sand and clay deposits. Previous geothermal assessments …
Evaluation Of Microfacies Controls On Hydrocarbon Seal Quality, Nchekwube Mbamalu
Evaluation Of Microfacies Controls On Hydrocarbon Seal Quality, Nchekwube Mbamalu
LSU Master's Theses
A microfacies based approach is proposed for the petrophysical prediction of the most effective hydrocarbon seals. Four distinct microfacies types deposited by different deep water depositional processes have been identified based on textural and mineralogical characteristics. Individual microfacies types include: 1) finely laminated, silt poor to slightly silty hemipelagic claystones; 2) faintly laminated, slightly to moderately silty distal hemiturbiditic claystones; 3) weakly laminated, moderately silty to slightly sandy intermediate hemiturbiditic mudstones; and 4) very silty and sandy proximal hemiturbiditic mudstones. Hemipelagic and distal hemiturbiditic claystones (microfacies types 1 and 2) containing well to modestly organized fabric, high total clay contents, …
New Age Control On A Mid-Shelf Grounding Event In Eastern Basin, Ross Sea, Amy Noelle Cone
New Age Control On A Mid-Shelf Grounding Event In Eastern Basin, Ross Sea, Amy Noelle Cone
LSU Master's Theses
It is widely accepted that the West Antarctic Ice Sheet (WAIS) was grounded at the continental shelf edge in Eastern Ross Sea during the Last Glacial Maximum (LGM), but the precise chronology is debated. Existing post-LGM ice retreat chronologies are considered suspect because nearly all have been developed using radiocarbon dating of acid-insoluble organics (AIO). Foraminifer tests yield more accurate radiocarbon dates than AIO because unlike loose sediment, foram tests are unlikely to be contaminated by allochthonous carbon, but unfortunately forams are sparse in Antarctic marine sediment cores. Here I utilized a new 3-D multibeam survey of a mid-continental-shelf grounding …
Origin Of Pyrite Nodules At The Top Of The Nantuo Diamictites, Southern China, Changjie Liu
Origin Of Pyrite Nodules At The Top Of The Nantuo Diamictites, Southern China, Changjie Liu
LSU Master's Theses
Pyrite nodules up to 20 cm in diameter are found at the top of the Marinoan (~635 Ma) Nantuo glacial diamictite as well as in the cap dolostones and shale/siltstones in the lower Doushantuo Formation in eastern Guizhou, southern China. Earlier studies on the occurrence and stable sulfur and triple oxygen isotope composition of barite in the cap dolostones concluded that seawater sulfate concentrations in shallow oceans in the South China Block were low during the deposition of the cap dolostones. Therefore, the occurrence of pyrite nodules suggests two scenarios: 1) Formation before the precipitation of the cap dolostone, when …
Geothermal Energy Potential Of South Bossier Parish, Louisiana, John Adam D'Aquin
Geothermal Energy Potential Of South Bossier Parish, Louisiana, John Adam D'Aquin
LSU Master's Theses
Northwestern Louisiana sits atop a geothermal anomaly that stretches across Eastern Texas and into Southern Arkansas. Geothermal gradients are observed in this area that are greater than the Gulf Coast average of 22-26oC/km. South Bossier Parish, in particular, could be an ideal location for economic production of electricity by conventional geothermal or enhanced geothermal projects due to ideal geothermal production temperatures of 120-180oC at a relatively shallow depth of approximately 3-5 km. A localized geothermal of 35oC/km gradient was determined using bottom-hole temperatures (BHTs) from 147 wells. At approximately 3.2 km depth, temperatures of approximately 130oC within the geopressured sands …
The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray
The Influences Of Microbial Diversity On Carbonate Geochemistry Across A Transition From Fresh To Saline Water In The Edwards Aquifer, Texas, Cassie Jo Gray
LSU Master's Theses
Microbially-mediated karstification through the production of metabolic byproducts has been well-documented in cave environments, but less is known about deep karstic settings. This research aimed to distinguish between microbial and geochemical influences on carbonate dissolution in the Edwards Aquifer, a prolific karst aquifer in central Texas, specifically from a transect of six wells across a transition from fresh to saline water in New Braunfels. For the first time, a portion of the aquifer’s bacterial diversity was examined from molecular 16S rRNA gene sequence analyses, which revealed that Alphaproteobacteria, Gammaproteobacteria, and Betaproteobacteria dominated the aquifer, with rare Bacteroidetes, Nitrospirae, and Firmicutes …
Volcanological And Petrogenetic Characteristics Of Komatiites Of The 3.3 Ga Saw Mill Complex, Weltevreden Formation, Barberton Greenstone Belt, South Africa, Matthew Stephen Huber
Volcanological And Petrogenetic Characteristics Of Komatiites Of The 3.3 Ga Saw Mill Complex, Weltevreden Formation, Barberton Greenstone Belt, South Africa, Matthew Stephen Huber
LSU Master's Theses
The Saw Mill Complex (SMC) is a 1275 m thick layered komatiitic sequence in the 3.3 Ga Weltevreden Formation, uppermost stratigraphic unit of the Onverwacht Group in the northern part of the Barberton Greenstone Belt, South Africa. A series of ultramafic complexes in the Weltevreden Formation have been interpreted as layered ultramafic intrusions, consisting of thick, layered ultramafic units of peridotite, pyroxenite, dunite, and gabbro. However, recent work on the Pioneer complex of the Weltevreden Formation has demonstrated an extrusive origin of komatiites and tuffs. The Weltevreden Formation has been less studied than other Onverwacht Group units. It is likely …
Metamorphic Rocks In The Sawtooth Mountains, Idaho, Usa: A Window Into The Precambrian Basement Of Southwest Laurentia, Kyle Michael Metz
Metamorphic Rocks In The Sawtooth Mountains, Idaho, Usa: A Window Into The Precambrian Basement Of Southwest Laurentia, Kyle Michael Metz
LSU Master's Theses
The western North American craton consists of a mosaic of Precambrian basement terranes that developed through episodes of microcontinent collision and magmatic arc accretion. Defining the extent and boundaries of these terranes is critical to deciphering the Precambrian development of Laurentia. The poorly exposed Selway terrane occurs between the Archean Wyoming province and the Neoproterozoic rifted margin of Laurentia. A rare exposure of Precambrian metamorphic rocks, the Sawtooth Metamorphic Complex (SMC), crops out over 33 km2 in the Sawtooth Mountains of Idaho, USA, and potentially provides a window into the deep crust of the region. Field mapping, petrographic analyses, and …
Speciation Of Heavy Metals In Disturbed And Undisturbed Sediments From Atchafalaya Bay, Houma Navigation Canal, And Southwest Pass, Louisiana, Amanda Jo Zimmerman
Speciation Of Heavy Metals In Disturbed And Undisturbed Sediments From Atchafalaya Bay, Houma Navigation Canal, And Southwest Pass, Louisiana, Amanda Jo Zimmerman
LSU Master's Theses
In coastal Louisiana it is common to use dredge spoil to build marshland that has been lost due to a variety of factors. Under various conditions such as deposition in a drained oxygenated environment, metals in the spoil can become more bioavailable posing a threat to the ecosystem. This study compares metal availability in natural and dredged sediments to determine what changes occur in nature. Forty four samples from three locations, Atchafalaya Delta, Houma Navigation Canal, and Southwest Pass, were analyzed for 13 common elements with known or potentially harmful health effects; Al, As, Ba, Be, Cd, Cr, Co, Cu, …
Diatom Stratigraphy Defining Ice Sheet Grounding Chronology, Ross Sea, Antarctica, Juan Manuel Chow
Diatom Stratigraphy Defining Ice Sheet Grounding Chronology, Ross Sea, Antarctica, Juan Manuel Chow
LSU Doctoral Dissertations
Evidence of Antarctic ice sheet behavior and paleoenvironment is often approached from proxy records because there is a dearth of direct records from Antarctica itself. The studies presented here seek to augment our knowledge of translations of the West Antarctic Ice Sheet’s (WAIS) marine termination based on direct biostratigraphic evidence. Diatom analyses were conducted from two areas of Ross Sea, Antarctica. In the first study, diatoms were used to constrain the age of diamictons from five seismic units in the Eastern Basin and thus expand our knowledge of WAIS behavior during the Southern Hemisphere Last Glacial Maximum (LGM). All five …
Oxidation Of Reduced Sulfur Compounds: A Triple-Oxygen-Isotope Perspective, Issaku E. Kohl
Oxidation Of Reduced Sulfur Compounds: A Triple-Oxygen-Isotope Perspective, Issaku E. Kohl
LSU Doctoral Dissertations
The Earth’s geochemical evolution is recorded in the rocks that compose its lithosphere. Specifically, sulfate minerals have been identified as being repositories of information concerning the past hydrosphere, atmosphere and biosphere. This is due to the non-labile nature of SO42- and its ability to store a record of the oxidative reactions and oxygen sources involved in its formation. Microbial dissimilatory sulfate reduction (MDSR) and sulfide oxidation cause oxygen from H2O and O2 to be trapped to varying degrees in ambient, dissolved SO42-. In order to better interpret the H2O and O2 signals in SO42-, we must deepen our understanding of …
Eastern Mediterranean Pore Waters: Clues Into The Geochemical Pathways From Evaporated Seawater To Basinal Brines, Jessica A. Mumphrey
Eastern Mediterranean Pore Waters: Clues Into The Geochemical Pathways From Evaporated Seawater To Basinal Brines, Jessica A. Mumphrey
Honors Capstones
No abstract provided.
The Storm 2.0 Project Next Generation Hurricane Data Collection, Santhana Krishnan Balaji
The Storm 2.0 Project Next Generation Hurricane Data Collection, Santhana Krishnan Balaji
Honors Capstones
No abstract provided.
Provenance Studies Of Volcanic Clasts From The Santa Fe Group, San Luis Basin, Colorado: A Guide To Tectonic Evolution, Corine Kay Armstrong
Provenance Studies Of Volcanic Clasts From The Santa Fe Group, San Luis Basin, Colorado: A Guide To Tectonic Evolution, Corine Kay Armstrong
LSU Master's Theses
Volcanic clasts at the base of the Tertiary Santa Fe Group of the San Luis Basin (SLB), a major extensional feature of the northern Rio Grande Rift, provide evidence for the direction of sediment transport and timing of regional tectonic events. A combination of clast whole rock geochemistry (major and trace element), mineral chemistry (amphibole, biotite, pyroxene and feldspar) and geochronology (40Ar/39Ar of amphibole and biotite and U-Pb of zircons) is used to constrain the possible source scenarios. Several potential sources with requisite geochemical and geochronological information exist for the Santa Fe Group volcanic clasts including rocks from Spanish Peaks …
A Geochemical Paleoecological Analysis Of Miocene Mammalian Mega Fauna Of Fort Polk, Louisiana, Travis Lamar Atwood
A Geochemical Paleoecological Analysis Of Miocene Mammalian Mega Fauna Of Fort Polk, Louisiana, Travis Lamar Atwood
LSU Master's Theses
Through a combination of vertebrate paleontology and geochemistry much can be discovered about the environments about the past. Fort Polk’s vertebrate fossil sites are important because they reflect a time when the Antarctic ice cap was just beginning to form during the middle Miocene cooling period just after the middle Miocene Climatic Optimum (~15Ma). This study tested the hypothesis that Miocene seasonality will be preserved in the isotopic geochemistry of terrestrial vertebrate remains at central North American Gulf Coastal sites. Geochemistry was used to understand fossil diagenesis, faunal communities and paleoenvironments. Fort Polk, LA sites range in age from 13.5 …