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Articles 211 - 240 of 835
Full-Text Articles in Earth Sciences
Characterizing The Low Net-To-Gross, Fluviodeltaic Dry Hollow Member Of The Frontier Formation, Western Green River Basin, Wyoming, Scott Romney Meek
Characterizing The Low Net-To-Gross, Fluviodeltaic Dry Hollow Member Of The Frontier Formation, Western Green River Basin, Wyoming, Scott Romney Meek
Theses and Dissertations
The Frontier Formation in the Green River Basin of southwestern Wyoming consists of Late Cretaceous (Cenomanian-Turonian) marine and non-marine sandstones, siltstones, mudstones and coals deposited on the western margin of the Cretaceous Interior Seaway. Tight gas reservoirs exist in subsurface fluviodeltaic sandstones in the upper Frontier Formation (Dry Hollow Member) on the north-south trending Moxa Arch within the basin. These strata crop out in hogback ridges of the Utah-Idaho-Wyoming Thrust Belt approximately 40 km west of the crest of the Moxa Arch. Detailed, quantitative outcrop descriptions were constructed using emerging photogrammetric techniques along with field observations and measured sections at …
Geologic Mapping Of The Vernal Nw Quadrangle, Uintah County, Ut, And Stratigraphic Relationships Of The Duchesne River Formation And Bishop Conglomerate, Casey Andrew Webb
Geologic Mapping Of The Vernal Nw Quadrangle, Uintah County, Ut, And Stratigraphic Relationships Of The Duchesne River Formation And Bishop Conglomerate, Casey Andrew Webb
Theses and Dissertations
Detailed mapping (1:24,000), measured sections, and clast counts in conglomerates of the Duchesne River Formation and Bishop Conglomerate in the Vernal NW quadrangle in northeastern Utah reveal the middle Cenozoic stratigraphic geometry, the uplift and unroofing history of the eastern Uinta Mountains, and give evidence for the pulsed termination of Laramide uplift. The Unita Mountains are an EW-trending reverse fault bounded and basement-cored, Laramide uplift. The oldest unit of the Duchesne River Formation, the Eocene Brennan Basin Member, contains 80-90% Paleozoic clasts and <20% Precambrian clasts. Proximal to the Uinta uplift the conglomerates of this member are dominated by Paleozoic Madison Limestone clasts (70-90% of all clasts). Farther out into the basin, Paleozoic clasts still dominate in Brennan Basin Member conglomerates, but chert clasts are more abundant (up to 43%) showing the efficiency of erosion of the carbonate clasts over a short distance (~5 km). Conglomerates in the progressively younger Dry Gulch Creek, Lapoint, and Starr Flat members show a significant upward increase in Precambrian clasts with 34-73% Uinta Mountain Group and 8-63% Madison Limestone. Duchesne River Formation has a significant increase in coarse-grained deposits from the southern parts of the quadrangle (20-50% coarse) to the northern parts (75% coarse) nearer the Uinta uplift. The lower part of the Duchesne River Formation exhibits a fining upward sequence representing a tectonic lull. Clast count patterns show that pebbly channel deposits in the south maintain similar compositions to their alluvial fan counterparts. To the north, the fine-grained Lapoint and Dry Gulch Creek members of the Duchesne River Formation appear to pinch out completely. This can be explained by erosion of these fine-grained deposits or by lateral facies shifts before deposition of the next unit. Starr Flat Member conglomerates were deposited above Lapoint Member siltstones and represent southward progradation of alluvial fans away from the uplifting mountain front. Similarities in composition and sedimentary structures have caused confusion surrounding the contact between the Starr Flat Member and the overlying Bishop Conglomerate. Within the Vernal NW quadrangle, we interpret this contact as an angular unconformity (the Gilbert Peak Erosion Surface) developed on the uppermost tilted red siltstone of the Starr Flat Member sometime after 37.9 Ma. Stratigraphic and structural relationships reveal important details about the development of a Laramide mountain range: 1) sequential unroofing sequences in the Duchesne River Formation, 2) progradation of alluvial fans to form the Starr Flat Member, 3) and the unconformable nature of the Gilbert Peak Erosion Surface lead to the conclusion that there were at least 3 distinct episodes of uplift during the deposition of these formations. The last uplift episode upwarped the Starr Flat Member constraining the termination of Laramide uplift in the Uinta Mountains to be after deposition of the Starr Flat Member and prior to deposition of the horizontal Bishop Conglomerate starting at about 34 Ma. This, combined with 40Ar/39Ar ages of 39.4 Ma from the Dry Gulch Creek and Lapoint member, show …20%>
Thermal Consolidation Of Dredge Sand For Artificial Reef Formations, Alexandro Trevino
Thermal Consolidation Of Dredge Sand For Artificial Reef Formations, Alexandro Trevino
Theses and Dissertations
Coral Reef ecosystems have degraded over years due to a variety of environmental issues such as ocean acidification. The continuous stress has detrimental effects on coral reef ecosystems that can possibly lead to the loss of the ecosystem. Our research aims to construct a prototype of an artificial reef by consolidating dredge sand from the ship channels of South Texas. Consolidation is achieved through an aluminum polytetrafluoroethylene self-propagating high temperature process that yields a solid formation to mimic the physical properties of coral reef structures. Using thermodynamic calculations, the variation of initial components was determined that reached an adiabatic temperature …
Lithofacies And Sequence Architecture Of The Lower Desert Creek Sequence, Middle Pennsylvanian, Aneth, Utah, Chanse James Rinderknecht
Lithofacies And Sequence Architecture Of The Lower Desert Creek Sequence, Middle Pennsylvanian, Aneth, Utah, Chanse James Rinderknecht
Theses and Dissertations
Middle Pennsylvanian (Desmoinesian) strata of the Lower Desert Creek (LDC) sequence within the sub-surface Greater Aneth Field (GAF) reflect a hierarchy of 4th and 5th order carbonate-dominated cycles. The Lower Desert Creek sequence, along the studied transect are composed of eight carbonate facies deposited on an east-facing shelf. There is a lateral transition from open marine algal buildup from the southeast (cores R-19, Q-16, O-16, and J-15) to a more restricted lagoonal environment to the northwest (core K-430 and E-313). The Lower Desert Creek sequence within the GAF contains three main parasequence sets: a basal, relatively deep-water unit (LDC 1), …
Sedimentology And Taphonomy Of The Abydosaurus Mcintoshi Quarry, (Naturita Formation, Early Cretaceous, Latest Albian), Dinosaur National Monument, Utah, Aaron Daniel Holmes
Sedimentology And Taphonomy Of The Abydosaurus Mcintoshi Quarry, (Naturita Formation, Early Cretaceous, Latest Albian), Dinosaur National Monument, Utah, Aaron Daniel Holmes
Theses and Dissertations
The holotypic locality of the brachiosaurid titanosauriform sauropod, Abydosaurus mcintoshi, is quarry DNM-16, located in Dinosaur National Monument. The bones are preserved near the base of a heterolithic, trough cross stratified to planar bedded sandstone channel complex. The trough cross to planar bedded sandstones mark times of variable flow with times of high flow velocity based on bones whose upper surfaces were eroded before final burial. The abundance of mud with the dominant medium to fine sand, and poorly confined sandstone channels indicate the bones were transported and buried in medial to distal intermittent flows of a distributive fluvial …
Formation Of Rapakivi Feldspars In The Deer Isle Granite Complex, Coastal Maine: In Situ Lead Isotope And Trace Element Analysis, William Desmond Obrien
Formation Of Rapakivi Feldspars In The Deer Isle Granite Complex, Coastal Maine: In Situ Lead Isotope And Trace Element Analysis, William Desmond Obrien
Theses and Dissertations
Rapakivi and alkali feldspar phenocrysts from the Deer Isle Granite Complex were investigated using in situ trace element and Pb isotope geochemistry to see if magma mixing or isothermal decompression was responsible for their formation. Pb isotope and trace element profiles, along with CL imagery of quartz phenocrysts, indicate compositional changes in the magma chamber occurred during rapakivi and alkali feldspar growth. Repeated episodes of magma mixing/replenishment by relatively isotopically primitive and LREE enriched magmas (along with hybridized variations with the host magma) created localized disequilibration. Alkali feldspar phenocrysts proximal to these zones of thermal perturbation were first resorbed and …
Evaluating Relationships Between Rock Strength And Longitudinal Stream Profile Morphometry In The Southern Guadalupe Mountains, Texas, Samuel T. Schoenmann
Evaluating Relationships Between Rock Strength And Longitudinal Stream Profile Morphometry In The Southern Guadalupe Mountains, Texas, Samuel T. Schoenmann
Theses and Dissertations
Landscapes record information about the tectonic, climatic, and lithologic environments in which they form (Yang et al., 2015). When one or more of these environmental conditions change spatially or temporally, the landscape responds through erosion and thus, develops representative geomorphic features (Ritter et al., 2011). Since the nineteenth century, it has been clear that bedrock strength and erodibility play an important role in landscape evolution and geomorphology (Lifton et al., 2009). However, the nuances of variable erodibility remain poorly understood. The implications of this limited understanding lies within landscape evolution models. While these models show strong qualitative relationships between longitudinal …
Evaluating Fault-Line Escarpment Exposure In The Guadalupe Mountains Of West Texas And New Mexico, Audrey Anne Happel
Evaluating Fault-Line Escarpment Exposure In The Guadalupe Mountains Of West Texas And New Mexico, Audrey Anne Happel
Theses and Dissertations
The Permian stratigraphy of the Guadalupe Mountains is well-known due to the impeccable exposure of Permian strata along distinct escarpments that define the boundaries of the range. Even though the Permian strata have been closely examined to understand the associated petroleum reservoirs in the adjacent Delaware basin, little work has been done on the escarpments that expose the well-known rocks at the surface by way of tectonic and erosional processes. The development of escarpments are directly affected by multiple processes that create the landscape, and can be used as a tool to temporally and spatially constrain tectonic and erosional activity …
Investigating The Application Of Multibeam Sonar And Remotely Operated Vehicles In Fish Population Monitoring On Artificial Reefs, Robert Figueroa-Downing
Investigating The Application Of Multibeam Sonar And Remotely Operated Vehicles In Fish Population Monitoring On Artificial Reefs, Robert Figueroa-Downing
Theses and Dissertations
Implementation of ROVs and multibeam imaging sonar in fisheries research has the potential to improve the accuracy and efficiency of current monitoring practices. This study aimed to 1) compare ROV video and diver abundance estimates; 2) evaluate fish length measurement accuracy from sonar; 3) investigate key differentiating sonar characteristics. Results indicate: 1) Diver surveys captured greater diversity of species; survey methods were comparable with regards to conspicuous species (r = 0.089, p = 0.074); 2) Length measurements from multibeam imaging sonar had high predictive power (Rho = 0.998; p < 0.001) of actual standard lengths and; 3) variations between samples were largely due to swim bladder echo, relative position of the target fish, and schooling characteristics. We conclude that 1) ROVs are less apt at observing cryptic species; 2) The Blueview P900-90 sonar can accurately measure fish length; and 3) swim bladder morphology plays an important role in fish identification.
Nutrient Loading Reduction In A Tile Drained Agricultural Watershed Through Watershed-Scale Cover Cropping: A High Resolution Analysis, Benjamin Gerald Bruening
Nutrient Loading Reduction In A Tile Drained Agricultural Watershed Through Watershed-Scale Cover Cropping: A High Resolution Analysis, Benjamin Gerald Bruening
Theses and Dissertations
Nutrient pollution originating from agricultural regions in the Midwest is a serious issue, leading to pollution of drinking water sources as well as large hypoxic zones in the Gulf of Mexico. The source of much of this contamination has been shown to be runoff from agricultural fields in the Upper Mississippi River Basin. One method that has been shown to reduce this pollution from the Upper Mississippi River Basin is the planting of winter cover crops. Winter cover crops such as rye and tillage radish have been shown to significantly reduce nitrate exported from agricultural fields, even in tile-drained watersheds …
Creating A Scaling Relationship Between Peak Discharge And Drainage Area To Identify Tile Drainage Inputs Into An Agricultural Stream, Ryan Plath
Theses and Dissertations
Tile drains have been shown to contribute to high levels of nitrate in agricultural streams. Locations of tile drains on a watershed scale, however, are often unknown due to tile drains being located on many separate parcels of private property. This study evaluates the ability of a methodology, using scaling relationships between discharge and drainage area, for locating areas of large tile drainage contribution to Money Creek, in McLean County, Illinois. Additionally, this study examines the difference in scaling relationships and physical stream hydrology between tileflow and no-tileflow conditions. Eight stream sites were created in the watershed, that recorded stage …
Near-Salt Stratal Geometries And Implications For The Evolution Of The Onion Creek Diapir Moab, Ut, Ethan L. Cook
Near-Salt Stratal Geometries And Implications For The Evolution Of The Onion Creek Diapir Moab, Ut, Ethan L. Cook
Theses and Dissertations
The Onion Creek Diapir is one of many salt domes proximal to the Uncompahgre thrust front of the ancestral rockies in the Paradox Basin. It is comprised of Paradox Formation evaporites and large blocks of Honaker Trail Formation carbonates that were deformed by loading of Permian Cutler Formation progradational alluvial to fluvial fans. The history of salt movement in the Onion Creek Diapir is recorded in the near-salt strata. Large salt bodies and their adjacent mini-basins evolve conforming to a complex relationship between salt withdrawal, creating localized accommodation, and sediment deposition. Migrating mini-basin depo-centers, thinned and folded strata, and spatial …
Weathering Sequence Of Young Basalts: A Case Study From Kohala, Hawaii, Kimberly Francis Sowards
Weathering Sequence Of Young Basalts: A Case Study From Kohala, Hawaii, Kimberly Francis Sowards
Theses and Dissertations
Exposed weathering profiles of a series of Pololu lava flows in Kohala, Hawaii are ideal for investigating the sequence of reactions/reaction pathways of weathered basalt. Weathering reactions for saprolites show mineral sequences that include feldspar → halloysite ± gibbsite + solutes; clinopyroxene → hematite + minor halloysite + solutes; olivine → hematite + solutes; magnetite → hematite or other Fe-oxides/hydroxides. However, the presence of smectite in four samples suggests that smectite-group clays may form as short lived intermediates at the base of the weathering profile. Regionally, on Kohala, soils and saprolites are dominated by halloysite with small quantities of other …
Exploration Of The Northern Illinois Bedrock Surface, Matthew Rhoads
Exploration Of The Northern Illinois Bedrock Surface, Matthew Rhoads
Theses and Dissertations
The purpose of this study is to deconstruct the relationship between the Leaf River anticline and the preglacial bedrock paleo topography at the eastern terminus of the Plum River Fault Zone in Ogle County, Illinois. A geostatistical approach was used to model the subsurface elevation of the bedrock paleo topography and the Leaf River anticline. The contour maps derived from the elevation models provided detailed depictions of the ancient bedrock landscape and subsurface structure in the study area. The Leaf River anticline is interpreted to be a component of hanging wall anticline at the terminus of the Plum River Fault …
Dynamics Of Nitrate, Phosphorus, And Suspended Sediment Transport In Two Agricultural Streams In Central Illinois, Luke W. Lampo
Dynamics Of Nitrate, Phosphorus, And Suspended Sediment Transport In Two Agricultural Streams In Central Illinois, Luke W. Lampo
Theses and Dissertations
Nutrients such as nitrate and phosphorus are necessary for life, but excessive amounts can be detrimental. Large amounts of nutrients entering bodies of water can lead to hypoxic zones such as the one in the Gulf of Mexico. Nutrients are also problematic in drinking water reservoirs, as high concentrations of nitrate in drinking water can cause health conditions such as blue baby syndrome and high phosphorus concentrations can lead to algal blooms. Suspended sediment leads to reservoir sedimentation, habitat degradation, and is able to transport particulate nutrients. High nutrient and sediment concentrations are a recurring problem in the drinking water …
A Quaternary Climate Record From A Uinta Mountains, Usa, Fen Core With Emphasis On Sediment Pyrolysis, Samuel Abraham Hillam
A Quaternary Climate Record From A Uinta Mountains, Usa, Fen Core With Emphasis On Sediment Pyrolysis, Samuel Abraham Hillam
Theses and Dissertations
The northern slopes of the Uinta Mountains, Utah were previously glaciated and contain many landslides. The Tokewanna Landslide is very large and lacks Quaternary faults. Presumably, increased moisture was the failure trigger. A Quaternary climate record from a cored fen, developed in a small basin between hummocks, was reconstructed using sediment pyrolysis, biomass balance, and magnetic susceptibility. Pyrolysis is used to define Hydrogen Indices that are used to delineate wetter and drier conditions based on the kerogen type - Type III being drier, and Type II wetter. The data were matched to a time/depth curve and compared to other Uinta …
Facies Analysis, Sedimentary Petrology, And Reservoir Characterization Of The Lower Triassic Sinbad Limestone Member Of The Moenkopi Formation, Central Utah: A Synthesis Of Surface And Subsurface Data, Kristopher Michael Powell
Facies Analysis, Sedimentary Petrology, And Reservoir Characterization Of The Lower Triassic Sinbad Limestone Member Of The Moenkopi Formation, Central Utah: A Synthesis Of Surface And Subsurface Data, Kristopher Michael Powell
Theses and Dissertations
Lower Triassic strata in the Wellington Flat and Tully cores reflect a lateral transition from shallow water strata (Wellington Flats core) to strata that indicate deposition on a relatively more distal, storm-dominated ramp (Tully core). The Sinbad Member, along with the upper part of the underlying Black Dragon Member and the lower part of the overlying Torrey Member (Moenkopi Formation), are composed of ten carbonate, siliciclastic and mixed carbonate/siliciclastic facies deposited on a west-facing ramp/shelf that reached maximum flooding during Smithian time. Individual beds and facies display a large degree of lateral homogeneity and regional persistence in the study area. …
A Comparison Of Pesticide Monitoring Programs, State Vs. Federal, Justin Marshall
A Comparison Of Pesticide Monitoring Programs, State Vs. Federal, Justin Marshall
Theses and Dissertations
Exposure to pesticide residues continues to be a threat to both human and environmental health despite increased efforts in the agricultural industry to control end-product levels. Multiple government agencies routinely sample and screen common agricultural commodities (fruits and vegetables) for pesticide residues, albeit to do so they use different commodity sampling methods and satisfy different program objectives. Often, results of such screening programs are used in a supplementary fashion in human and environmental health studies, but rarely are the results studied against one another. Six years of archived data (narrowed down from 14) of two separate pesticide monitoring programs were …
Subsurface Transport In A North Inlet, South Carolina Salt Marsh: A Porewater Salinity Model, Carolyn Ryan
Subsurface Transport In A North Inlet, South Carolina Salt Marsh: A Porewater Salinity Model, Carolyn Ryan
Theses and Dissertations
Subsurface transport in coastal salt marshes influences the nutrient budget of coastal environments, but is not fully understood. To expand our understanding of this transport, a simple numerical model was developed. The model simulated vertical transport of salt through the surficial muds at a North Inlet marsh on the coastal plain of South Carolina. To improve the model, a tracer study was utilized to calculate the average velocity of groundwater flow through the system. The model was compared with porewater salinity measured using tension samplers and passive diffusion samplers. Each method produced different, uncorrelated results. However, accounting for macro-pores in …
A Study Of Two Digital Hydrological Networks In South Carolina And An Assessment Of Site Reconnaissance Results From The Sc Department Of Health And Environmental Control Probability Survey For Streams And Rivers, Caitlin Smith
Theses and Dissertations
The South Carolina Department of Health and Environmental Control (SCDHEC), Surface Water Monitoring Section utilizes a probability survey to assess water quality conditions of streams and rivers in the state. The Generalized Random-Tessellation Stratified survey design prioritizes specific stream order (size) subpopulations and spatial distribution in the generation of potential sample sites, and is intended to survey only perennial stream reaches. Site reconnaissance is conducted to assess site suitability and accessibility. The stream characteristics associated with accepted and rejected sites have been recorded since the late 1990s/early 2000s. Data from 2001-2016 was analyzed to assess apparent trends in both rejected …
Drivers Of Sediment Accumulation And Nutrient Burial In Coastal South Carolina Residential Stormwater Detention Ponds, William Schroer
Drivers Of Sediment Accumulation And Nutrient Burial In Coastal South Carolina Residential Stormwater Detention Ponds, William Schroer
Theses and Dissertations
Stormwater detention ponds are widely utilized as control structures to manage runoff waters during storm events. These sediments also represent significant sites of organic carbon and nutrient burial. Here, carbon (C) and nutrient sources and burial rates were determined in 14 residential stormwater detention ponds throughout coastal counties of South Carolina. Bulk sediment accumulation was directly correlated with catchment impervious surface coverage (R2 = 0.90) with sediment accumulation rates ranging from 0.06 to 0.50 cm y-1. These rates of sediment accumulation and subsequent pond volume loss are lower than expected indicating that required maintenance dredging schedules be reassessed. Strong, positive …
High Resolution Gravity, Helicopter Magnetic, And Electromagnetic Study, Haile Gold Mine, South Carolina, Saad Saud Alarifi
High Resolution Gravity, Helicopter Magnetic, And Electromagnetic Study, Haile Gold Mine, South Carolina, Saad Saud Alarifi
Theses and Dissertations
The goal of this research was to calibrate and test geophysical methods for the detection of disseminated sulfides in the area of the Haile Gold Mine, South Carolina. The work focused on the calibration of high resolution gravity, and helicopter electromagnetic (EM) and magnetic data provided by OceanaGold. While high resolution potential field data (gravity and magnetics) has not been proven to be effective at small scales in exploration for disseminated sulfides, there is a strong regional correlation between high amplitude gravity and magnetic anomalies and the most productive gold mines in the Carolina terrane. Helicopter EM methods have been …
The Summerville Formation: Evidence For A Sub-Horizontal Stratigraphic Sequence Below The Post-Rift Unconformity In The Middleton Place Summerville Seismic Zone, Joseph Edward Getz
The Summerville Formation: Evidence For A Sub-Horizontal Stratigraphic Sequence Below The Post-Rift Unconformity In The Middleton Place Summerville Seismic Zone, Joseph Edward Getz
Theses and Dissertations
The Middleton Place Summerville Seismic Zone (MPSSZ) near Summerville, South Carolina was the site of renewed extensive investigation, beginning in the 1970’s, for the source of the 1886 Charleston earthquake. Reactivation of faults associated with a putative fault-bounded Triassic rift basin through analysis of seismic reflection, seismic refraction, and well data has since become the favored interpretation for the source of MPSSZ seismicity. Critical to this interpretation is the association of continental redbed sedimentary rocks in Triassic basins throughout the North American Atlantic margin. Reanalysis of 18 seismic reflection profiles and 25 seismic refraction profiles within the MPSSZ suggests that …
Sanitary Sewer Overflows In Columbia, South Carolina And Their Impact On Mercury And Metal Cycling, Alison Emmons
Sanitary Sewer Overflows In Columbia, South Carolina And Their Impact On Mercury And Metal Cycling, Alison Emmons
Theses and Dissertations
Objectives. Microbial pathogens and their threat to human health have been the primary concern of sanitary sewer overflows (SSO); however, SSOs may also be a source of metals, including methylmercury, to local waterways. We hypothesized that SSOs had elevated concentrations of metals compared to nearby reference creeks.
Methods. Unfiltered and filtered (0.2 μm) surface water samples were collected monthly between November 2015 and March 2016 from three sewage-impacted creeks in Columbia, South Carolina. During this period, three sewage events were captured including an active SSO, a ruptured force main sewer pipe, and one site downstream from SSOs. In October 2016 …
Utilizing Structure-From-Motion Photogrammetry And Unmanned Aerial Vehicles To Characterize Variability In Fluvial Deposits From The Salt Wash Member Of The Morrison Formation, East-Central Utah, John Chesley
Theses and Dissertations
Modern fluvial systems are highly variable, often containing the entire spectrum of fluvial styles (e.g., braided to meandering). This variability is difficult to capture in ancient fluvial deposits due to limited 1- and 2-dimesional exposures, which provide only a snapshot of the depositional history at one location. As a result, researchers are forced to interpolate between exposures and develop regional scale models that often underestimate the complexity and variability seen in modern environments. Outcrops of the Upper Jurassic Salt Wash Member of the Morrison Formation in east-central Utah, USA provide a relatively unique opportunity to examine ancient fluvial sandstone bodies …
Serpentinization And Synthesis: Searching For Abiotic And Biotic Non-Volatile Organic Molecules In The Subsurface Of The Atlantis Massif, Katherine A. Hickok
Serpentinization And Synthesis: Searching For Abiotic And Biotic Non-Volatile Organic Molecules In The Subsurface Of The Atlantis Massif, Katherine A. Hickok
Theses and Dissertations
High concentrations of hydrogen created during serpentinization can promote the formation of abiotic organic carbon molecules such as methane, formate, and short chain hydrocarbons and, in laboratory experiments, larger molecules containing up to 32 carbon atoms. Subsurface archaeal and bacterial communities can use these reduced compounds for metabolic energy. International Ocean Discovery Project Expedition 357 drilled 17 boreholes into the Atlantis Massif with the goals of investigating carbon cycling and the presence of life in a zone of active serpentinization. The expedition recovered multiple lithologies including gabbros, basalts, carbonate sands, and serpentinites. A subset of contrasting lithologies were analyzed for …
Carbon Sources To Microbes And Cryoconite On Alaskan Alpine Glacier Surfaces, Drake Mccrimmon
Carbon Sources To Microbes And Cryoconite On Alaskan Alpine Glacier Surfaces, Drake Mccrimmon
Theses and Dissertations
Cryoconite are depressions in the ice surface filled with diverse microorganisms and dark debris, which are reducing albedo and increasing glacier melt. In order to understand cryoconite carbon composition and carbon sources to microorganisms living on glacier surfaces, bulk organic carbon and microbial lipids from supraglacial cryoconite sediment within the ablation zones of Spencer, Matanuska, and Mendenhall glaciers in southern Alaska have been coupled with radiocarbon (14C) analyses. The microbial lipids analyzed in these studies, phospholipid fatty acids (PLFA), are components of microbial membranes, quickly degrade after cell death, and give a snapshot of the viable microbial community. PLFA structure …
Glacial To Holocene Changes In Eastern Equatorial Pacific Deep-Water Chemistry And Circulation, Natalie E. Umling
Glacial To Holocene Changes In Eastern Equatorial Pacific Deep-Water Chemistry And Circulation, Natalie E. Umling
Theses and Dissertations
It has been hypothesized that the oceans store CO2 during glacial periods and then release it to the atmosphere, causing the onset of warm interglacial periods (Sigman and Boyle, 2000). Documenting this past transfer of CO2 between the oceans and atmosphere is of utmost importance for better understanding the impact that anthropogenic CO2 has and will have on Earth’s climate. The last deglaciation is a good analogue to modern increases in CO2 and temperature and is recent enough to be studied using radiocarbon. This period provides important insights into the nature of climate changes during the transition from glacial to …
Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton
Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton
Theses and Dissertations
Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response …
Tectonic Studies Of Southeastern North America: The Suwannee Basin, Brunswick Suture Zone, Osceola Arc, And Pangean Transcurrent Fault System, Susannah Katherine Boote
Tectonic Studies Of Southeastern North America: The Suwannee Basin, Brunswick Suture Zone, Osceola Arc, And Pangean Transcurrent Fault System, Susannah Katherine Boote
Theses and Dissertations
A series of exotic terranes with complex tectonostratigraphic relationships construct the North American margin and record information critical to understanding the evolution of the Appalachian orogen. The Coastal Plain cover remains a challenge in this region; however, synthesis of seismic reflection, seismic refraction, well, and aeromagnetic data allows for a substantially revised interpretation of the basement rocks and structures that comprise the pre-Mesozoic crust of southeastern North America. These data reveal: (1) a Neoproterozoic subduction zone and paired continental-margin arc are preserved in Gondwanan crust in southeastern North America, (2) the Gondwanan Suwannee Basin of Early to Mid-Paleozoic age is …