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Articles 1 - 30 of 112
Full-Text Articles in Physical Sciences and Mathematics
Evaluation Of The Community Multiscale Air Quality Model For Simulating Winter Ozone Formation In The Uinta Basin, Rebecca Matichuk, Gail Tonnesen, Deborah Luecken, Rob Gillam, Sergey L. Napelenok, Kirk R. Baker, Donna Schwede, Ben Murphy, Detlev Helmig, Seth N. Lyman, Shawn Roselle
Evaluation Of The Community Multiscale Air Quality Model For Simulating Winter Ozone Formation In The Uinta Basin, Rebecca Matichuk, Gail Tonnesen, Deborah Luecken, Rob Gillam, Sergey L. Napelenok, Kirk R. Baker, Donna Schwede, Ben Murphy, Detlev Helmig, Seth N. Lyman, Shawn Roselle
Bingham Research Center
The Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) models were used to simulate a 10 day high-ozone episode observed during the 2013 Uinta Basin Winter Ozone Study (UBWOS). The baseline model had a large negative bias when compared to ozone (O3) and volatile organic compound (VOC) measurements across the basin. Contrary to other wintertime Uinta Basin studies, predicted nitrogen oxides (NOx) were typically low compared to measurements. Increases to oil and gas VOC emissions resulted in O3 predictions closer to observations, and nighttime O3 improved when reducing the deposition velocity …
Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung
Abiotic- And Biotic-Formation Of Manganese Oxides And Their Fate In Environmental Systems, Haesung Jung
McKelvey School of Engineering Theses & Dissertations
Manganese (hydr)oxide (Mn (hydr)oxide) minerals are ubiquitous in aquatic and terrestrial environments. These minerals have high surface areas and are highly sorptive and redox active. From decades of accumulated knowledge about natural redox cycling, we have found that Mn (hydr)oxides play critical roles as electron donors and acceptors in elemental geochemical cycling and biological metabolisms in nature. Thus, Mn (hydr)oxides have garnered increasing interest to understand natural systems. Considering the variety of redox reactions with Mn (hydr)oxides in nature, it is also expected that there should be diverse pathways to form Mn (hydr)oxides through abiotic and biotic processes. Previous studies …
Phosphate Speleothems In Caves Developed In Iron Ores And Laterites Of The Carajás Mineral Province (Brazil) And A New Occurrence Of Spheniscidite, Alan R.L. Albuquerque, Rômulo S. Angélica, Daniele F. Gonçalves, Simone P.A. Paz
Phosphate Speleothems In Caves Developed In Iron Ores And Laterites Of The Carajás Mineral Province (Brazil) And A New Occurrence Of Spheniscidite, Alan R.L. Albuquerque, Rômulo S. Angélica, Daniele F. Gonçalves, Simone P.A. Paz
International Journal of Speleology
The Carajás Mineral Province has one of the largest concentrations of caves in Brazil, and its iron ore is among the country’s main exports. As a result of iron ore intense extraction, new environmental policies have been implemented. In an attempt to balance economic activity and environmental conservation, an inventory and a relevance-based classification of caves were implemented in 2008 as criteria for environmental licensing of mining ventures. This implementation motivated the present study of phosphate speleothems in Carajás’ caves developed in ferriferous rocks. The objectives of this study are to describe the phosphate minerals and their formation processes based …
Stable Cu, Fe, And Ni Isotopic Systematics Of The Sudbury Offset Dikes And Associated Rocks, Peter Christoffersen
Stable Cu, Fe, And Ni Isotopic Systematics Of The Sudbury Offset Dikes And Associated Rocks, Peter Christoffersen
Electronic Thesis and Dissertation Repository
The stable isotope ratio compositions of Fe, Ni, and Cu (δ56Fe, δ60Ni, and δ65Cu) are reported for the first time in rocks from the Sudbury Igneous Complex (SIC). Massive sulfide ores, Quartz Diorite (QD), Inclusion bearing Quartz Diorite (IQD), and rocks from members of the Main Mass of the SIC were analyzed. The objective was to better understand the origin(s) and source(s) of the Offset Dikes and the associated sulfide mineralization. Based on stable isotope ratios and petrographic observations, two distinct types of sulfide mineralization hosted within the Offset Dikes are identified. Massive sulfide …
Whole Rock Geochemistry And Tectonic Setting Of Jurassic Aged Lisar Granite, Talesh Mountains, North Iran, Mohssen Moazzen, Roghieh Bozorg Seghi̇nsara, Hossein Shei̇khi̇ Kari̇zaki̇, Mohsen Pourkermani̇, Afshin Ashja Ardalan
Whole Rock Geochemistry And Tectonic Setting Of Jurassic Aged Lisar Granite, Talesh Mountains, North Iran, Mohssen Moazzen, Roghieh Bozorg Seghi̇nsara, Hossein Shei̇khi̇ Kari̇zaki̇, Mohsen Pourkermani̇, Afshin Ashja Ardalan
Bulletin of the Mineral Research and Exploration
The Late Jurassic aged Lisar granite in North Iran is in tectonic contact of the form of thrust and strike slip faults with Upper Cretaceous sandy limestone and is covered by Paleogene polygenetic conglomerate in the Talesh Mountain at the western continuation of the Alborz range. The rock samples of the granite are pink coloured and coarse-gained with K-feldspar, quartz, plagioclase, biotite and amphibole. The Lisar granite is more likely emplaced in an extensional environment indicated with numerous space filling silica-rich aplitic veins in the rocks. The granite samples are moderately altered and feldspars are changed to sericite and clay …
Soil-Grapevine Interactions: Insight From Verdicchio In The Marche Wine Region, Italy, Megan Luna Barlow
Soil-Grapevine Interactions: Insight From Verdicchio In The Marche Wine Region, Italy, Megan Luna Barlow
Theses and Dissertations
Verdicchio is a white grape varietal notably grown in the Marche wine region of east-central Italy within two Denominazione Origine Controllata (DOCs); Castelli di Jesi and Matelica, located less than 50 km apart. Jesi lies in the Apennine foothills near the coast of the Adriatic Sea and produces a smooth wine noted with apple-pear undertones and crisp, clean acidity. Conversely, Matelica is located in a synclinal valley of a fold-and-thrust belt and produces stronger wine with penetrating floral aromas and bold acidity. While macro-climatic variations do exist between DOCs, this research focuses on geological variations, specifically variations in soil composition, …
A Public Humanity: The Application Of Isotopic Analysis To The Intersection Between Body And Law At The Milwaukee County Poor Farm Cemetery, Shannon Kate Freire
A Public Humanity: The Application Of Isotopic Analysis To The Intersection Between Body And Law At The Milwaukee County Poor Farm Cemetery, Shannon Kate Freire
Theses and Dissertations
The Milwaukee County Poor Farm Cemetery is an umbrella term used to describe the four cemeteries that were used by Milwaukee County from 1878 through 1974 for the burial of the indigent, unclaimed, institutionalized, and anatomized. Three of these cemeteries remain undisturbed. The primary focus of this research is the twice-excavated Cemetery II (Wisconsin Burial Site 47BMI0076), in use between 1882 and 1925. Archaeological excavations in 1991-1992 and again in 2013 resulted in the recovery of over 2,400 individuals from this cemetery location.
In Wisconsin, legislative efforts to govern indigent burial and dissection mediated competing aspirations between medical education and …
Provenance Analysis Of The Grover Gravel Using Detrital Zircon Geochronology, Petrology And Heavy Mineral Analysis, Grant Spoering
Provenance Analysis Of The Grover Gravel Using Detrital Zircon Geochronology, Petrology And Heavy Mineral Analysis, Grant Spoering
MSU Graduate Theses
The Grover Gravel in the St. Louis, Missouri area contains a mix of chert, quartzite, jasper, and ironstone in clast sizes ranging up to 60 cm. The gravel varies in thickness from a veneer to over 30 feet and rests on upland surfaces at elevations sometimes exceeding 300 feet above the floors of major valleys. A pre-Pleistocene age generally has been proposed or assumed for the gravel, which classically has been interpreted to be a meandering-stream deposit atop an extensive flat upland surface, which was subsequently eroded and dissected by rejuvenated streams. However, large quartzite boulders in the gravel also …
Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard
Geophysical Delineation Of Megaporosity And Fluid Migration Pathways For Geohazard Characterization Within The Delaware Basin, Culberson County, Texas, Jonathan David Woodard
Electronic Theses and Dissertations
ABSTRACT
Differential dissolution of gypsum karst within the Delaware Basin poses a significant threat to infrastructure that society depends on. The study area is located in Culberson County, Texas and traverses a distance of approximately 54 kilometers along RM 652 within the Gypsum Plain which is situated on the northern margin of the Chihuahua Desert and includes outcrops of Castile and Rustler strata that host karst geohazards. Regions of karst geohazard potential have been physically surveyed proximal to the study area in evaporites throughout the Castile Formation outcrop; minimal hazards, in comparison to the Castile Formation, have been documented in …
Cave Monitoring In The Béke And Baradla Caves (Northeastern Hungary): Implications For The Conditions For The Formation Cave Carbonates, György Czuppon, Attila Demény, Szabolcs Leél-Őssy, Mihály Óvari, Mihály Molnár, József Stieber, Klaudia Kiss, Krisztina Kármán, Gergely Surányi, László Haszpra
Cave Monitoring In The Béke And Baradla Caves (Northeastern Hungary): Implications For The Conditions For The Formation Cave Carbonates, György Czuppon, Attila Demény, Szabolcs Leél-Őssy, Mihály Óvari, Mihály Molnár, József Stieber, Klaudia Kiss, Krisztina Kármán, Gergely Surányi, László Haszpra
International Journal of Speleology
In order to use speleothems in the reconstruction of past climate and environmental changes it is necessary to understand the environmental and hydrological processes that determine the physico-chemical conditions of carbonate precipitation and hence speleothem formation. Therefore, in this study an extended monitoring program was conducted in the Béke and Baradla caves located in the Aggtelek region (Northeastern Hungary). The studied caves are rich in speleothem and flowstone occurrences with great potential for paleoclimatology studies. The monitoring activity included measurements of atmospheric and cave temperatures, CO2 concentration in cave air, as well as chemical and isotopic compositions of water …
U–Pb Dating Of Cave Spar: A New Shallow Crust Landscape Evolution Tool, D. D. Decker, V. J. Ployak, Y. Asmeron, Matthew Lachniet
U–Pb Dating Of Cave Spar: A New Shallow Crust Landscape Evolution Tool, D. D. Decker, V. J. Ployak, Y. Asmeron, Matthew Lachniet
Geoscience Faculty Research
In carbonate terranes, rocks types that provide apatite are not available to effectively use apatite fission track (AFT) or (U/Th)‐He chronometry (AHe). Here we suggest that calcite cave spar can be an effective chronometer and complimentary to AFT and AHe thermochronometers in carbonate regions such as our study area, the Guadalupe Mountains of southeastern New Mexico, and west Texas. Our measured depth of cave spar deposition is 500 ± 250 m beneath the regional water table, formed at temperatures of 40° to 80°C, indicating that these caves and their spar crystals form near the supercritical CO2‐subcritical CO2 boundary where we …
Resolving Chronological And Temperature Constraints On Antarctic Deglacial Evolution Through Improved Dating Methodology, Cristina Subt
Resolving Chronological And Temperature Constraints On Antarctic Deglacial Evolution Through Improved Dating Methodology, Cristina Subt
USF Tampa Graduate Theses and Dissertations
In order to determine the timing of Antarctic ice sheet retreat and advance during the Late Quaternary, various tools are used to measure the age of marginal marine sediments. Carbonate 14C dating is a well-established approach, but requires foraminiferal microfossils, shells or other carbonate materials that are rare in most Antarctic regions, and may also suffer from vital effects, which can result in variability of up to 500 years in living organisms. Bulk acid insoluble organic (AIO) 14C dates are frequently as an alternative, but this approach works best where high productivity and sedimentation rates reign, and not too well …
Geochemistry Of The Dome Mine Ankerite Veins: Insights Into The Multi-Stage Enrichment Of A World-Class Orogenic Gold Deposit, Jessica M. Stromberg
Geochemistry Of The Dome Mine Ankerite Veins: Insights Into The Multi-Stage Enrichment Of A World-Class Orogenic Gold Deposit, Jessica M. Stromberg
Electronic Thesis and Dissertation Repository
The Dome Mine in the world-class Timmins camp has produced over 16 Moz of gold during its 108 year production history. This gold endowment is the result of multistage enrichment of which the first stage is a set of ankerite veins that extend over 5,400 m in strike and 1,500 m vertically. A deposit wide geochemical study of the Dome ankerite veins was undertaken to characterize their genesis, geochemistry, and role in the deposit mineralization history. Samples and mapping from new and historic mine workings, bulk rock geochemistry, and stable isotope geochemistry were used to constrain the depositional context of …
Paleoenvironmental Variation And Provenance Records From Neogene Deep Sea Sediment Of The South China Sea, Chang Liu
LSU Doctoral Dissertations
I employed several paleoenvironmental proxies by utilizing deep sea sediment from the largest marginal basin in east Asia, namely the South China Sea (SCS), to reconstruct the long term paleoenvironmental variation in SE Asia since the Neogene. Sediments deposited within the SCS were mainly delivered by several major fluvial systems whose catchment basins cover several geological blocks in SE Asia. By analyzing the sediment’s geochemical and mineralogical characteristics, several indices which are affected by the source of the sedimentary influx, as well as the weathering state could be built and applied to constrain my paleoenvironmental reconstructions
Two deep sea drilling …
Geothermal Flux And Phreatic Speleogenesis In Gypsum, Halite, And Quartzite Rocks, Giovanni Badino
Geothermal Flux And Phreatic Speleogenesis In Gypsum, Halite, And Quartzite Rocks, Giovanni Badino
International Journal of Speleology
The first layers of rock underground are in thermal contact with the external atmosphere mainly through infiltrating meteoric water. This relatively cool zone absorbs rising geothermal energy, which heats the water. If the aquifer consists of gypsum, halite or quartzite, the water at those depths is usually salt-saturated, so the increase in temperature renders the water aggressive again. This in turn leads to rock dissolution and formation of phreatic conduits. This way, the geothermal flow creates caves that do not necessarily reach the surface. This paper analyzes the speed of the excavation, which, in different types of rocks, depends only …
When, How, And Why Did The West Antarctic Ice Sheet Retreat In The Ross Sea Since The Last Glacial Maximum Using Foraminiferal And Porewater Geochemistry, Matthew Decesare
When, How, And Why Did The West Antarctic Ice Sheet Retreat In The Ross Sea Since The Last Glacial Maximum Using Foraminiferal And Porewater Geochemistry, Matthew Decesare
LSU Doctoral Dissertations
The Antarctic Ice Sheets (AIS) began to retreat from their Last Glacial Maximum (LGM) position sometime after 19,000 years ago. However, the corrosive waters circulating around Antarctica has prevented the recovery of radiocarbon-dateable material, hindering the development of deglacial chronologies. During Expedition NBP1502B to the eastern Ross Sea, an unprecedented quantity of fossil foraminifera and bivalves were recovered. Radiocarbon-dated specimens have been used to constrain the timing of West-AIS retreat from Whales Deep basin and Ross Bank. Whales Deep samples show that the WAIS retreated from its LGM position on the continental shelf edge by 14,700 ± 400 calibrated radiocarbon …
The Role Of High-Elevation Headwater Runoff In Streamflow Generation And Water Supply In The Northern Andes, Colombia, Laura Lotero Lozano
The Role Of High-Elevation Headwater Runoff In Streamflow Generation And Water Supply In The Northern Andes, Colombia, Laura Lotero Lozano
USF Tampa Graduate Theses and Dissertations
Water security requires that sufficient quantities of water be available at critical times. This is particularly challenging for high-intensity urban and agricultural settings. In underdeveloped nations, streamflow is commonly the preferred water source, as it is readily available and delivered cost-free to users. Yet, the sources of these critical streamflows are often unknown. This issue is salient in the Northern Andes, where basic knowledge of controlling factors for the quantity, quality, and timing of runoff is lacking. High-elevation headwaters are the primary catchment areas in the Northern Andes, but the extent of water providing to municipalities in the Northern Andes …
A Geochemical And Petrological Analysis Of The San Rafael Volcanic Field, Utah, Danielle Koebli
A Geochemical And Petrological Analysis Of The San Rafael Volcanic Field, Utah, Danielle Koebli
USF Tampa Graduate Theses and Dissertations
The San Rafael Volcanic Field, Utah, is a 4.6 Ma extinct monogenetic field that is found in the Northern Transition Zone of the Colorado Plateau. The field has been eroded, leaving the dikes, conduits, and sills visible. Within the sills we see evidences of immiscibility in the form of an intermediate syenite (~50 wt% SiO2) enclosed in a mafic shonkinite (~48 wt % SiO2). Field relations indicate that sills were formed due to single events (Richardson et al., 2015), which makes in-situ differentiation the process at the origin of both rock types. Geochemical data supports differentiation …
Arctic And North Atlantic Paleo-Environmental Reconstructions From Lake Sediments, Gregory A. De Wet
Arctic And North Atlantic Paleo-Environmental Reconstructions From Lake Sediments, Gregory A. De Wet
Doctoral Dissertations
ABSTRACT
ARCTIC AND NORTH ATLANTIC PALEO-ENVIRONMENTAL RECONSTRUCTIONS FROM LAKE SEDIMENTS MAY 2017 GREGORY A. DE WET, B.Sc., BATES COLLEGE M.Sc., UNIVERSITY OF MASSSCHUSETTS, AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS, AMHERST Directed by: Drs. Raymond S. Bradley and Isla S. Castañeda There are few fields in the discipline of Earth Science that hold more relevancy in 2017 than studies of earth’s climate. Called the “perfect problem” considering its complexity and magnitude, climate change will continue to be one of the greatest challenges humanity will face in the 21st century. And while numerical models provide valuable information on conditions in the future, …Bonneville Basin Data, Larry Benson
Bonneville Basin Data, Larry Benson
Data Sets for USGS Research
In the Bonneville Basin folder, all data were reported in: Benson, L.V., Lund, S.P., Smoot, J.P., Rhode, D.E., Spencer, R.J., Verosub, K.L., Louderback, L.A., Johnson, C.A., Rye, R.O., Negrini, R., 2011. The rise and fall of Lake Bonneville between 45 and 10.5 ka. Quaternary International 235, 57-69.
http://digitalcommons.unl.edu/usgsstaffpub/726
General Comment: in most cases an age model based on 14C analyses is not included with the data sets although ones were created for the original publications. Given the general problems with 14C ages in the lakes of the Great Basin, age models based on paleomagnetic secular variation (PSV) are …
Groundwater And Subsurface Water In A Landscape With Shallow Bedrock: Implications For Agricultural Nutrient Export, Laura Kelley, Hunter R. Evans, Reid E. Buskirk, Jonathan M. Malzone, Walter S. Borowski
Groundwater And Subsurface Water In A Landscape With Shallow Bedrock: Implications For Agricultural Nutrient Export, Laura Kelley, Hunter R. Evans, Reid E. Buskirk, Jonathan M. Malzone, Walter S. Borowski
EKU Faculty and Staff Scholarship
Controls on nutrient export from agricultural landscapes include regional hydrological and geological conditions. In many central Kentucky basins shallow fractured bedrock produces focused groundwater discharge and flashy runoff events. Eastern Kentucky University’s Meadowbrook Farm is currently experimenting with nutrient sequestration techniques; however the effectiveness of these techniques given the local hydrogeology needs to be quantified. Our objective was to determine the potential pathways for nutrient export by mapping key hydrologic features and using a watershed approach. The key features mapped were springs, tile drains, runoff channels, land use and the underlying geology. We chose a 0.46 km2 watershed to …
Geochemical Characteristics And Storm Dynamics Of Surface Waters And Groundwater At Eastern Kentucky University’S Meadowbrook Farm, Madison County, Kentucky, Reid E. Buskirk, Walter S. Borowski, Jonathan M. Malzone
Geochemical Characteristics And Storm Dynamics Of Surface Waters And Groundwater At Eastern Kentucky University’S Meadowbrook Farm, Madison County, Kentucky, Reid E. Buskirk, Walter S. Borowski, Jonathan M. Malzone
EKU Faculty and Staff Scholarship
Agricultural activities often contaminate watersheds with excess nutrients leading to poor water quality and eutrophication. Eastern Kentucky University’s Meadowbrook Farm raises crops and livestock, contributing dissolved nutrients to the neighboring Muddy Creek watershed. Consequently, the Farm is developing methods to sequester and limit nutrient contamination.
Before phosphorous sequestration methods can be tested, the geochemistry of surface water and groundwater on the Farm need to be better understood to determine hydrological pathways. We use naturally-occurring, dissolved cations as tracers to identify the contribution of different water sources and interpret storm events.
Water samples taken from springs (groundwater), surface water, and storm …
Further Study Of Garnet Xenocrysts In New York City Migmatites, Stanley Schleifer, Nazrul I. Khandaker
Further Study Of Garnet Xenocrysts In New York City Migmatites, Stanley Schleifer, Nazrul I. Khandaker
Publications and Research
The authors have previously published an article at the 2004 Geological Society of America Annual Meeting, Petrogenetic Significance of Garnets in the Bedrock of New York City, in which they suggested that the garnet xenocrysts observed in the quartzofeldspathic zones of the migmatites, so frequently seen both at the surface, and below the surface pursuant to the construction of the Manhattan portion of New york City Water Tunnel #3, were a refractory residue of the anatectic melting of the immediately surrounding schistose bedrock. Although the relatively high melting point temperature of garnet compared to other minerals in the surrounding …
Diurnal And Seasonal Variation In Groundwater Nitrate -N Concentration In A Saturated Buffer Zone, Joseph Miller
Diurnal And Seasonal Variation In Groundwater Nitrate -N Concentration In A Saturated Buffer Zone, Joseph Miller
Theses and Dissertations
Surface water pollution by nitrate (NO3-) is identified as a critical problem in agricultural land-use areas. Excess NO3- loading causes eutrophication and hypoxia in near-shore marine waters such as the Gulf of Mexico. Diversion of agricultural runoff into saturated buffer zones reduces NO3- loading. Although the mechanisms responsible for NO3- reduction in saturated buffer zones are well characterized, little is known about how NO3- concentrations vary temporally and what factors control those changes. The objective of this study is to understand NO3- concentration and environmental factor variability in a saturated buffer zone on a diurnal scale within and among the …
A Near-Global Atmospheric Distribution Of N2o Isotopologues, Peter F. Bernath, Mahdi Yousefi, Eric Buzan, Chris D. Boone
A Near-Global Atmospheric Distribution Of N2o Isotopologues, Peter F. Bernath, Mahdi Yousefi, Eric Buzan, Chris D. Boone
Chemistry & Biochemistry Faculty Publications
The distributions of the four most abundant isotopologues and isotopomers (N2O, 15NNO, N15NO, and NN18O of nitrous oxide have been measured in the Earth's stratosphere by infrared remote sensing with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer. These satellite observations have provided a near-global picture of N2O isotopic fractionation. The relative abundances of the heavier species increase with altitude and with latitude in the stratosphere as the air becomes older. The heavy isotopologues are enriched by 20-30% in the upper stratosphere and even more over the poles. These observations are …
Selenium Distribution And Cycling In The Eastern Equatorial Pacific Ocean, Zoe Wambaugh
Selenium Distribution And Cycling In The Eastern Equatorial Pacific Ocean, Zoe Wambaugh
OES Theses and Dissertations
Oxygen minimum zones in oceanic waters have become increasingly important to the marine environment and society. Low oxygen waters affect not only the distribution and abundance of marine organisms, but also impact the solubility and transport of trace elements that are of biological importance, with the chemical speciation and solubility depending on the actual redox poise of the waters. One redox sensitive trace element of interest is selenium, which can be both toxic and essential for organisms, depending on its chemical speciation. In 2013, the US GEOTRACES program completed the GP16 transect from Peru to Tahiti, going through the oxygen …
Depositional And Environmental Controls On Oxygen And Carbon Isotope Compositions Of Late Pleistocene To Mid-Holocene Shelly Fauna From The Huron Basin, Ontario, Canada, Jane Wilson
Electronic Thesis and Dissertation Repository
The δ¹⁸O and δ¹³C of aragonitic mollusc shells were analyzed from nine sites in the Huron Basin, Ontario, Canada. These sites represent three lake phases spanning the Late Pleistocene to the mid-Holocene (Algonquin, Transitional, and Nipissing) and three depositional environments (fluvial, estuarine, and lacustrine). Depositional environment controls mollusc δ¹⁸O more strongly than climate. The source of carbon and climate control the δ¹³C of the shelly fauna. Shells from fluvial sites are most depleted of ¹⁸O and exhibit the greatest antipathetic δ¹³C-δ¹⁸O covariation. This reflects the dynamic nature of this system. Lacustrine sites have …
40ar/39ar Ages And Zircon Petrochronology For The Rear Arc Of The Izu-Bonin-Marianas Intra-Oceanic Subduction Zone, Graham Dm Andrews
40ar/39ar Ages And Zircon Petrochronology For The Rear Arc Of The Izu-Bonin-Marianas Intra-Oceanic Subduction Zone, Graham Dm Andrews
Faculty & Staff Scholarship
Long-lived intra-oceanic arcs of Izu-Bonin-Marianas (IBM)-type are built on thick, granodioritic crust formed in the absence of pre-existing continental crust. International Ocean Discovery Program Expedition 350, Site U1437, explored the IBM rear arc to better understand continental crust formation in arcs. Detailed petrochronological (U–Pb geochronology combined with trace elements, oxygen and hafnium isotopes) characterizations of zircon from Site U1437 were carried out, taking care to exclude potential contaminants by (1) comparison of zircon ages with ship-board palaeomagnetic and biostratigraphic ages and 40Ar/39Ar geochronology, (2) analysing zircon from drill muds for comparison, (3) selectively carrying out in situ analysis in petrographic …
Conduction Plus Convection Heat Flow Modeling For The Linga Complex, Peruvian Coastal Batholith, Luciano Uriel González Olivares
Conduction Plus Convection Heat Flow Modeling For The Linga Complex, Peruvian Coastal Batholith, Luciano Uriel González Olivares
Loma Linda University Electronic Theses, Dissertations & Projects
Factors affecting the thermal evolution of the Linga magmatic intrusion in the Ica-Pisco area of the Peruvian Coastal Batholith were studied using field work, petrography, geochemistry data, and computer modeling. Field work and petrography involved collecting samples for geochemical analysis and documenting widespread propylitic and potassic hydrothermal alteration. Major element geochemistry was used to estimate rock density, viscosity, liquidus temperature, and water content. The δ18O values of seven fresh samples showed a slightly increasing west-east and old-young trend of approximately 7-8‰, indicating an increasing crustal component. The δ18O and δD values for eleven altered samples indicated that alteration came mostly …
Investigating Core Shale Depositional Environments Of Late Pennsylvanian Cyclothems Utilizing Geochemical Proxies To Test The Superestuarine Model, Bryce A. Mathis
Investigating Core Shale Depositional Environments Of Late Pennsylvanian Cyclothems Utilizing Geochemical Proxies To Test The Superestuarine Model, Bryce A. Mathis
LSU Master's Theses
The Late Paleozoic Midcontinent Sea (LPMS) inundated vast areas of the North American interior during glacio-eustatic transgressions, depositing widespread black shales facies within the core shale intervals of major cyclothems. These black shale deposits are unique because no modern analogs can adequately explain the depositional environments and model for organic matter preservation across such vast ancient epicontinental settings. One possible explanation is that a superestuarine circulation system developed across the LPMS during humid interglacial phases, which promoted strong water column stratification and benthic anoxia.
The goal of this research was to test the validity of the superestuarine estuarine model and …