Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of South Florida (90)
- University of Nevada, Las Vegas (69)
- University of Nebraska - Lincoln (68)
- Western Kentucky University (34)
- Central Washington University (32)
-
- University of Kentucky (31)
- Portland State University (29)
- University of Arkansas, Fayetteville (28)
- Old Dominion University (27)
- Louisiana State University (25)
- University at Albany, State University of New York (25)
- University of New Mexico (25)
- University of Texas at El Paso (24)
- Eastern Kentucky University (22)
- Missouri State University (21)
- Stephen F. Austin State University (21)
- City University of New York (CUNY) (19)
- Missouri University of Science and Technology (19)
- Montclair State University (18)
- University of Southern Maine (16)
- Western Michigan University (15)
- West Virginia University (11)
- Michigan Technological University (9)
- Western University (9)
- Northern Illinois University (8)
- Fort Hays State University (7)
- Indiana State University (7)
- LSU New Orleans (7)
- Southern Methodist University (7)
- Boise State University (6)
- Keyword
-
- Geochemistry (117)
- Geology (47)
- Petrology (28)
- Karst (15)
- Provenance (15)
-
- Stable isotopes (15)
- Economic Geology (14)
- Groundwater (13)
- Mineralogy (13)
- Zircon (13)
- Earth sciences (12)
- Isotopes (12)
- Sulfide (12)
- Tectonics (12)
- Geochronology (11)
- Hydrogeology (11)
- Minerals (11)
- Paleoclimate (11)
- Basalt (10)
- Climate change (9)
- Petrography (8)
- Stratigraphy (8)
- Sulfur isotope (8)
- Trace elements (8)
- Volcanology (8)
- Antarctica (7)
- Chemostratigraphy (7)
- Copper (7)
- Fluid inclusions (7)
- Gas hydrate (7)
- Publication Year
- Publication
-
- UNLV Theses, Dissertations, Professional Papers, and Capstones (61)
- United States Geological Survey: Publications (52)
- International Journal of Speleology (31)
- USF Tampa Graduate Theses and Dissertations (29)
- Dissertations and Theses (26)
-
- Theses and Dissertations--Earth and Environmental Sciences (26)
- Geology Theses and Dissertations (24)
- Graduate Theses and Dissertations (23)
- Open Access Theses & Dissertations (23)
- All Master's Theses (22)
- EKU Faculty and Staff Scholarship (22)
- Earth and Planetary Sciences ETDs (22)
- Geology Faculty Publications (21)
- Graduate Theses/Dissertations (21)
- Electronic Theses and Dissertations (19)
- Department of Earth and Environmental Studies Faculty Scholarship and Creative Works (18)
- OES Theses and Dissertations (17)
- Maine Collection (16)
- Masters Theses (16)
- Masters Theses & Specialist Projects (15)
- LSU Master's Theses (14)
- Earth, Environmental, and Atmospheric Sciences Publications (12)
- Publications and Research (12)
- All Faculty Scholarship for the College of the Sciences (10)
- Graduate Theses, Dissertations, and Problem Reports (ETD) (10)
- Earth Sciences Publications (9)
- LSU Doctoral Dissertations (9)
- Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research (8)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (8)
- Graduate Research Theses & Dissertations (8)
- Publication Type
- File Type
Articles 301 - 330 of 850
Full-Text Articles in Geochemistry
Fluid-Mobile Trace Element Variability Of Serpentinites And Entrained Crustal Rocks Across The Mariana Forearc System, Raymond M. Johnston
Fluid-Mobile Trace Element Variability Of Serpentinites And Entrained Crustal Rocks Across The Mariana Forearc System, Raymond M. Johnston
USF Tampa Graduate Theses and Dissertations
In the Mariana subduction system, active serpentinite mud volcanoes are associated with the subduction of the Pacific plate beneath the Philippine plate in a non-accretionary convergent plate margin. This location offers a unique opportunity to study the subduction zone interface with little crustal contamination. The systematics of fluid-mobile trace elements (FME) (As, Cs, Rb, Sb, Tl, Pb, and Sr) in erupted serpentinite muds and entrained serpentinized ultramafic and mafic clasts can place constraints on the release of slab-derived fluids from the downgoing plate, and ultimately the pressure/temperature (P/TC°) conditions at which these fluids are mobilized.
The samples analyzed in this …
A Metasomatized Lithospheric Mantle Control On The Metallogenic Signature Of Post-Subduction Magmatism, David A. Holwell, Marco Fiorentini, Iain Mcdonald, Yongjun Lu, Andrea Giuliani, Daniel J. Smith, Manuel Keith, Marek Locmelis
A Metasomatized Lithospheric Mantle Control On The Metallogenic Signature Of Post-Subduction Magmatism, David A. Holwell, Marco Fiorentini, Iain Mcdonald, Yongjun Lu, Andrea Giuliani, Daniel J. Smith, Manuel Keith, Marek Locmelis
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
Ore deposits are loci on Earth where energy and mass flux are greatly enhanced and focussed, acting as magnifying lenses into metal transport, fractionation and concentration mechanisms through the lithosphere. Here we show that the metallogenic architecture of the lithosphere is illuminated by the geochemical signatures of metasomatised mantle rocks and post-subduction magmatic-hydrothermal mineral systems. Our data reveal that anomalously gold and tellurium rich magmatic sulfides in mantle-derived magmas emplaced in the lower crust share a common metallogenic signature with upper crustal porphyry-epithermal ore systems. We propose that a trans-lithospheric continuum exists whereby post-subduction magmas transporting metal-rich sulfide cargoes play …
Assessing Bioavailability, Metal Fractionation, Magnetic Susceptibility, And Organic Matter Interactivity In Mine-Waste Contaminated Sediments In Turkey Creek, Joplin, Missouri, Zachary Joseph Collette
Assessing Bioavailability, Metal Fractionation, Magnetic Susceptibility, And Organic Matter Interactivity In Mine-Waste Contaminated Sediments In Turkey Creek, Joplin, Missouri, Zachary Joseph Collette
Graduate Theses/Dissertations
Joplin, Missouri, part of the Tri-State Mining District (TSMD), has a long history of mining that resulted in mine waste piles proximal to the mines throughout the area. A local lead smelter also resulted in smelter fallout in Joplin. Mine waste pile runoff and local smelter fallout resulted in contamination of sediments, soils, and waterways. In the 1990s, remediation of residential soils and play areas began after blood lead levels in children were much higher than the national average. Soon afterwards, the chat piles were removed and used for beneficial reuse purposes. In May of 2011, an EF5 tornado devastated …
Provenance And Maximum Depositional Age Analysis Of The Moenave Formation Using Detrital Zircon U-Pb Geochronology And Sandstone Petrography, Asher Rea Boudreaux
Provenance And Maximum Depositional Age Analysis Of The Moenave Formation Using Detrital Zircon U-Pb Geochronology And Sandstone Petrography, Asher Rea Boudreaux
Graduate Theses and Dissertations
In southwestern Utah and northeastern Arizona, Moenave Formation (latest Triassic(?)-Jurassic) is bracketed by well-studied Mesozoic units extensively sampled for detrital zircon geochronology and is poorly documented in regard to provenance, representing an important gap in knowledge. The Moenave Formation provides a unique opportunity to employ detrital zircon U-Pb geochronology and sandstone petrography relevant to completing the paleogeographic, evolutionary, and climatic story of the region. This study aims to characterize the sedimentary provenance of the Moenave Formation and to identify, or at least improve constraints on, the stratigraphic position of the Triassic-Jurassic boundary (TJB) and placement of the end-Triassic extinction (ETE), …
The Paleozoic Sedimentary Rocks Of The Ouachita Mountains And Their Genetic Relationship To The Mississippi Valley-Type Mineralization In The Southern Ozark Region: Insights From Radiogenic Pb Isotopes And Trace Elements Studies, Christophe Wakamya Simbo
The Paleozoic Sedimentary Rocks Of The Ouachita Mountains And Their Genetic Relationship To The Mississippi Valley-Type Mineralization In The Southern Ozark Region: Insights From Radiogenic Pb Isotopes And Trace Elements Studies, Christophe Wakamya Simbo
Graduate Theses and Dissertations
Cluster of Pb and/or Zn deposits of the well-known Tri-State and Northern Arkansas Mississippi Valley Type (MVT) districts located north of the Arkoma basin and the Ouachita fold-thrust belt in north America are genetically connected to the Pennsylvanian-Permian Ouachita orogeny which triggered a South-North topographic gradient flow of basinal brines, leaching metal rich sediments en route. The objective of the research is twofold. First, to ascertain whether the organic-rich shales and sandstones from the study area provided metals during the mineralization event, which was coeval with the Ouachita orogeny. Second, to assess the depositional environment of the potential source rocks, …
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves, Camille H. Dwyer
Constraining The Oxygen Values Of The Late Cretaceous Western Interior Seaway Using Marine Bivalves, Camille H. Dwyer
Earth and Planetary Sciences ETDs
The Western Interior Seaway (WIS) remains an oceanographic enigma, including its circulation, similarity to the open ocean, and the fidelity of geochemical proxies to reconstruct paleoenvironments. Across the late Campanian and early Maastrichtian I test whether: 1) the WIS had unique δ18OVPDB compared to other marine settings, 2) increasing oceanographic restriction changed the stable isotope composition, and 3) biases, e.g., taxonomy or diagenesis, influenced stable isotope compositions. Results indicate distinct δ18OVPDB in the WIS compared to other marine settings. δ18OVPDB values were stable through time, suggesting insignificant oceanographic restriction and a …
Natural Salinization Of The Jemez River, New Mexico: An Insight From Trace Element Geochemistry, Jon K. Golla
Natural Salinization Of The Jemez River, New Mexico: An Insight From Trace Element Geochemistry, Jon K. Golla
Earth and Planetary Sciences ETDs
The Jemez River, a tributary of the Rio Grande in north-central New Mexico, receives thermal water input from the geofluids of the Valles Caldera, an active, high-temperature, liquid-dominated geothermal system. We focus on a ∼50-km portion of the northern Jemez River. This research extends previous decadal work (Crossey et al., in prep., 2013) on major chemistry in the river by characterizing the response of 16 trace elements to geochemical contributions from geothermal waters (McCauley, Spence, Soda Dam, and Jemez Springs springs and San Ysidro mineral waters), an area with copious hydrothermal degassing (Hummingbird), and two major tributaries (Rio San Antonio …
Identifying Characteristics Of Actionable Science For Drought Planning And Adaptation, Adam Wilke, Amanda Cravens
Identifying Characteristics Of Actionable Science For Drought Planning And Adaptation, Adam Wilke, Amanda Cravens
United States Geological Survey: Publications
Changing climate conditions can make water management planning and drought preparedness decisions more complicated than ever before. Federal and State natural resource managers can no longer rely solely on historical trends as a baseline and thus are in need of science that is relevant to their specific needs to inform important planning decisions. Questions remain, however, regarding the most effective and efficient methods for extending scientific knowledge and products into management and decision-making. This project analyzed two unique cases of water management to better understand how science can be translated into resource management actions and decision-making, focusing particularly on how …
Stable Isotope Geochemistry Of Shelled Marine Invertebrates: Wide-Ranging Applications, Nasser M. Al-Qattan
Stable Isotope Geochemistry Of Shelled Marine Invertebrates: Wide-Ranging Applications, Nasser M. Al-Qattan
USF Tampa Graduate Theses and Dissertations
Mollusks grow by adding discrete growth layers throughout their lifetime (i.e., accretion). More specifically, most marine mollusks precipitate their shells in oxygen isotopic equilibrium with seawater or with a constant offset from equilibrium. The stable oxygen isotope values (δ18O) of their shells are determined by the temperature and δ18O values of the surrounding water during calcification without significant vital effects. In comparison, the stable carbon isotope values (δ13C) of their shells reflect those of the dissolved inorganic carbon (δ13C- DIC) and respired carbon dioxide. Therefore, variations in the oxygen and carbon isotope …
Geothermometry Of H6 And L6 Chondrites And The Relationship Between Impact Processing And Retrograde Metamorphism, Michael Tyler Ream
Geothermometry Of H6 And L6 Chondrites And The Relationship Between Impact Processing And Retrograde Metamorphism, Michael Tyler Ream
Dissertations and Theses
Ordinary chondrites are the most common type of meteorite to fall to Earth and are composed of lithified primitive nebular materials which have experienced variable extents of thermal metamorphism and shock processing. They were subjected to radiogenic heating by incorporation of unstable short lived radionuclides such as 26Al in the early solar system.
The relationship between metamorphism and impact processing in ordinary chondrites is not fully understood. An unresolved issue in the study of ordinary chondrites is whether their original parent bodies were fragmented by impacts into rubble-pile bodies while they were still hot, or whether they retained their …
Rare Earth Geochemistry Of Apatitic Fossils From The Middle-Upper Ordovician Southern Margin Of Laurentia, Rafael Adrian Villanueva
Rare Earth Geochemistry Of Apatitic Fossils From The Middle-Upper Ordovician Southern Margin Of Laurentia, Rafael Adrian Villanueva
LSU Master's Theses
Widespread deposition of phosphate and a transition from tropical to cool water carbonates is seen throughout Middle-Upper Ordovician Nashville Dome area spanning the M4/M5 sequence boundary. Hypotheses explaining the onset of these lithologic changes have included the onset of glaciation, drawdown of CO2 related to the Guttenburg Isotope Carbon Excursion (GICE), and siliciclastic weathering, yet none of these studies have provided definitive evidence that shows any of these are the sole factor driving paleoenvironmental changes across the M4/M5 boundary. In order to test whether rapid subsidence along the southeastern margin of Laurentia may have caused an influx of phosphate …
Distribution And Origin Of Carbide In Ordinary Chondrites, Karla Rae Farley
Distribution And Origin Of Carbide In Ordinary Chondrites, Karla Rae Farley
Dissertations and Theses
To understand the occurrence and distribution of carbide minerals in ordinary chondrites, thirty meteorites were examined, twenty-eight ordinary chondrites and two iron meteorites. The occurrence of carbide, textures, and chemical compositions were examined in the 7 carbide-bearing meteorites. Two formation methods for carbide have been presented in previous research. These are aqueous alteration and shock heating, and they are examined for validity in this thesis. Additionally, one other formation method for carbide formation through impact and brecciation is put forth and examined. Textural differences between the carbide-magnetite assemblages (CMAs) observed by Krot et al., (1997) and those seen in this …
Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig
Geochemical Analysis Of The Chinchín Formation In Southern Ecuador, Katherine Ludwig
Celebration of Learning
The subduction of the Nazca Plate under the South American Plate has led to the uplift of the majority of the Andes Mountains, but in Ecuador, the Nazca Plate subducts underneath the North Andes Plate, which then collides with the South American Plate. This tectonic setting has formed two parallel mountain chains as well as a complex series of basins between them. However, the formations that make up these basins are poorly understood. This study focuses on the Chinchín Formation, an ~3.5 km thick, volcanic formation that serves as the bedrock of the Quingeo Basin in southern Ecuador. This study …
Petrogenesis Of Off-Axis Lavas Erupted Along The 8˚20’ N Seamount Chain, East Pacific Rise, Molly Kassandra Anderson
Petrogenesis Of Off-Axis Lavas Erupted Along The 8˚20’ N Seamount Chain, East Pacific Rise, Molly Kassandra Anderson
Boise State University Theses and Dissertations
Lavas erupted at off-axis seamounts provide a window into mantle heterogeneity and melting systematics that are not easily observed on-axis at fast spreading mid-ocean ridges (MORs). This is because axial melts are efficiently mixed and homogenized within shallow axial magma chambers prior to eruption. To understand the deeper magmatic processes contributing to oceanic crustal formation, we examine the compositions of lavas erupted along a chain of off-axis seamounts, adjacent to the East Pacific Rise (EPR). Essential questions include: (1) What is the range of compositional variability erupted off-axis and how does that compare to lavas erupted on-axis? (2) Is there …
Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley
Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley
Graduate Theses and Dissertations
Mean water age for spring discharge in Hot Springs National Park was calculated as approximately 4,400 years by Bedinger et al (1978) using carbon-14. Their analysis indicated that the water was a mixture of a small portion of cold water that was less than twenty years old with a preponderance of hot water. However, this result includes some error due to Bedinger et al. using general isotopic values for soil dissolved inorganic carbon and mineral carbon instead of obtaining actual values from the study area. A more accurate age calculation for the springs has been made possible by additional geological …
Geochemical Analysis Of Mississippian Cherts And Devonian-Mississippian Novaculites, Southern Midcontinent Region, Julie Mary Cains
Geochemical Analysis Of Mississippian Cherts And Devonian-Mississippian Novaculites, Southern Midcontinent Region, Julie Mary Cains
Graduate Theses and Dissertations
This study uses trace elements and radiogenic isotopes (Pb, Sr, and Nd) to investigate the origin and mode of formation for the siliceous deposits in the Lower Mississippian Boone Formation and the Devonian-Mississippian Arkansas Novaculite in the southern midcontinent. Mississippi Valley-type Pb-Zn ore deposits in the Tri-State District and the Northern Arkansas District were deposited by hydrothermal fluids, and highly radiogenic Pb isotope ratios suggest a genetic relationship between the Boone Formation chert (206Pb/204Pb ~ 21.59, 207Pb/204Pb ~ 15.87, 208Pb/204Pb ~ 40.10) and the MVT ores. Due to the very low concentration of Pb in the Boone chert (~2 ppm) …
Petrogenesis Of Unusual Occurrence Of Amphibole Asbestos In Mohave County, Arizona And Clark County, Nevada, Tomoyo Austin
Petrogenesis Of Unusual Occurrence Of Amphibole Asbestos In Mohave County, Arizona And Clark County, Nevada, Tomoyo Austin
UNLV Theses, Dissertations, Professional Papers, and Capstones
The term “asbestos” applies to six types of fibrous amphiboles or chrysotile with specific morphologies that are commercially mined and processed. Inhaling asbestos fibers is known to cause many negative health effects, including mesothelioma, several different cancers, various respiratory diseases and non-respiratory diseases, and fatalities. The recent years, several cases of non-occupational exposure to asbestos fibers raised an awareness of environmental exposure to naturally occurring asbestos (NOA) which refers to asbestiform minerals that fall out of the regulatory definition of asbestos.
There are two sources of NOA in the area, Wilson Ridge pluton, AZ, and Boulder City pluton, NV which …
Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner
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 …
Nitrogen And Phosphorus Uptake In An Urban Stream Ecosystem, Nicolette A. Sheffield
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 …
Variations Of Sedimentary Biogenic Silica In The Gulf Of Mexico During The Deepwater Horizon And Ixtoc-I Oil Spill., Jong Jin Lee
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
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. …
Assessing Paleo-Coastal Caves Evolution And Sea Level Changes In Mallorca: Results From Radiometric Dating Of Speleothems, Giuseppe Lucia
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 …
Stable Isotopes Of Clay Minerals From Autoclave Tests Of Oil Sands: Implications For Clay Formation During Steaming Of Alberta Clearwater Oil Sands, Shaoneng He, Fred J. Longstaffe, Zhihong Zhou
Stable Isotopes Of Clay Minerals From Autoclave Tests Of Oil Sands: Implications For Clay Formation During Steaming Of Alberta Clearwater Oil Sands, Shaoneng He, Fred J. Longstaffe, Zhihong Zhou
Earth Sciences Publications
In an effort to evaluate mineral-water isotopic exchange during cyclic steam stimulation (CSS), solutions and<2 μm berthierine-dominated solids from the Clearwater Formation oil sands of Alberta, Canada were analyzed for stable isotope compositions before and after reaction in autoclaves for 1008 h at 250 °C. There was no significant change in solution δ18O and δ2H, which is consistent with the high water/mineral ratio used in the experiments. The solids showed a marked decrease in both δ18O and δ2H following the experiments. Pre-run solids have δ18O of +9.5 to +12.9‰and …2>
Fluid-Present Anatexis Of Neoarchean Tonalite And Amphibolite In The Western Shandong Province, Chris Yakymchuk, Wenran Zhao, Yusheng Wan, Shoufa Lin, Fred Longstaffe
Fluid-Present Anatexis Of Neoarchean Tonalite And Amphibolite In The Western Shandong Province, Chris Yakymchuk, Wenran Zhao, Yusheng Wan, Shoufa Lin, Fred Longstaffe
Earth Sciences Publications
Metatonalite and amphibolite from the Taishan region of the Western Shandong Province in the North China Craton record c. 2.60 Ga fluid-present partial melting via the breakdown of biotite, plagioclase and quartz to produce peritectic hornblende and anatectic melt. Eight paired leucosome–melanosome samples from metatonalite and three paired samples from amphibolite were investigated to evaluate the composition of the melt. Hornblende, biotite and plagioclase in the leucosomes and hornblende and plagioclase in melanosomes from both rock types have similar compositions. Two leucosome samples from the metatonalite were influenced by the removal of heavy rare earth element-rich hornblende and the accumulation …
Stable Isotopic Characterization Of A Coastal Floodplain Forest Community: A Case Study For Isotopic Reconstruction Of Mesozoic Vertebrate Assemblages, Thomas M. Cullen, Fred Longstaffe, Ulrich G. Wortmann, Mark B. Goodwin, Li Huang, David C. Evans
Stable Isotopic Characterization Of A Coastal Floodplain Forest Community: A Case Study For Isotopic Reconstruction Of Mesozoic Vertebrate Assemblages, Thomas M. Cullen, Fred Longstaffe, Ulrich G. Wortmann, Mark B. Goodwin, Li Huang, David C. Evans
Earth Sciences Publications
Stable isotopes are powerful tools for elucidating ecological trends in extant vertebrate communities, though their application to Mesozoic ecosystems is complicated by a lack of extant isotope data from comparable environments/ecosystems (e.g. coastal floodplain forest environments, lacking significant C4 plant components). We sampled 20 taxa across a broad phylogenetic, body size, and physiological scope from the Atchafalaya River Basin of Louisiana as an environmental analogue to the Late Cretaceous coastal floodplains of North America. Samples were analysed for stable carbon, oxygen and nitrogen isotope compositions from bioapatite and keratin tissues to test the degree of ecological resolution that can …
Flood-Inundation Maps For The North Platte River At Scottsbluff And Gering, Nebraska, 2018, Kellan R. Strauch
Flood-Inundation Maps For The North Platte River At Scottsbluff And Gering, Nebraska, 2018, Kellan R. Strauch
United States Geological Survey: Publications
Digital flood-inundation maps for an 8.8-mile reach of the North Platte River, from 1.5 miles upstream from the Highway 92 bridge to 3 miles downstream from the Highway 71 bridge in Scottsbluff County, were created by the U.S. Geological Survey (USGS) in cooperation with the Cities of Scottsbluff and Gering, Nebraska. The flood-inundation maps, which can be accessed through the Flood Inundation Mapping (FIM) Program website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program?qt-science_center_objects=0#qt-science_center_objects, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the North Platte River at Scottsbluff, Nebr. (station number 06680500). Near-real-time …
Biodiversity And Distribution Of Benthic Foraminifera In Harrington Sound, Bermuda: The Effects Of Physical And Geochemical Factors On Dominant Taxa, Nam Le
Honors Theses
Harrington Sound, Bermuda, is a nearly enclosed lagoon acting as a subtropical/tropical, carbonate-rich basin in which carbonate sediments, reef patches, and carbonate-producing organisms accumulate. Here, one of the most important calcareous groups is the Foraminifera. Analyses of common benthic orders, including miliolids (Quinqueloculina and Triloculina spp.) and rotaliids (Homotrema rubrum, Elphidium spp., and Ammonia beccarii), are essential in understanding past and present environmental conditions affecting the island's coastal environment. These taxa have been studied previously; however, factors explaining their individual patterns of abundance in the Sound are not well detailed. The goal of this study is …
Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen
Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen
Faculty Publications
Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …
The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk
The Origin Of An Archean Batholith In Michigan’S Upper Peninsula, Brandi Petryk
Dissertations, Master's Theses and Master's Reports
The Southern Complex is part of the Archean Superior Province in the Upper Peninsula of Michigan and includes a batholithic sized body of Archean high-K megacrystic granitoid rocks informally called the Bell Creek granite. U-Pb zircon ages of the granitoid from previous studies suggest an emplacement age of ~2.6 Ga (Tinkham, 1997). Based on those ages the Bell Creek granite formed around the Archean-Proterozoic transition. This transition is a crucial time period in Earth’s history for crustal growth because of the onset of subduction and increased sedimentary environments at the end of the Archean (Taylor and McLennan, 1995). In this …
Response Of Vegetation In Open And Partially Wooded Fens To Prescribed Burning At Seney National Wildlife Refuge, Jane E. Austin, Wesley E. Newton
Response Of Vegetation In Open And Partially Wooded Fens To Prescribed Burning At Seney National Wildlife Refuge, Jane E. Austin, Wesley E. Newton
United States Geological Survey: Publications
The health and function of northern peatlands, particularly for fens, are strongly affected by fire and hydrology. Fens are important to several avian species of conservation interest, notably the yellow rail (Coturnicops noveboracensis). Fire suppression and altered hydrology often result in woody encroachment, altering the plant community and structure. Woody encroachment and its effects on biodiversity have become an increasing concern in the conservation and management of plant communities. This study evaluated the effects of spring and summer prescribed burns on the plant community, cover, and structure in open and partially wooded fens at Seney National Wildlife Refuge, Michigan, using …