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Articles 1 - 15 of 15
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Metamorphic And Structural Control Of Magnetism Within The Lower Continental Crust, Northern Saskatchewan, Canada, Jeffrey R. Webber
Metamorphic And Structural Control Of Magnetism Within The Lower Continental Crust, Northern Saskatchewan, Canada, Jeffrey R. Webber
Doctoral Dissertations
The linking of geophysical information to tectonometamorphic processes holds great potential for the surveying of vast remote areas of the planet and may allow for the transcendence of observational scales. Investigations concerning magnetic properties of the lower continental crust can reveal an incredible wealth of information concerning the conditions of metamorphism, regional extent of deformation, and controls on the magnetic architecture of the lithosphere. This dissertation presents three contributions aimed at the integration of petrology, structural geology, and rock magnetism in order to investigate the magnetic nature of the lower continental crust, constrain tectonometamorphic processes at the regional scale in …
Aggregation And Coagulation Of C60 Fullerene As Affected By Natural Organic Matter And Ionic Strength, Hamid Mashayekhi
Aggregation And Coagulation Of C60 Fullerene As Affected By Natural Organic Matter And Ionic Strength, Hamid Mashayekhi
Doctoral Dissertations
With widespread production and use of C60 fullerene nanoparticles, their release to the environment and natural waters is inevitable. The colloidal nature of C60 fullerene in the aquatic environment significantly influences its behavior in the environment including its transport, bioavailability and toxicity to different organisms. Natural organic matter (NOM) is a ubiquitous and reactive material in aquatic environments with significant structural heterogeneity. Therefore, the effect of NOM molecules on the colloidal behavior of fullerene particles needs to be studied. A major part of NOM consists of humic acids (HA). HAs have pronounced effects on the aggregation of C …
Fault Interaction Within Restraining Bend Fault Systems, Aviel Rachel Stern
Fault Interaction Within Restraining Bend Fault Systems, Aviel Rachel Stern
Masters Theses
Numerical simulations of a 15° restraining bend analog claybox experiment include considering the fault geometry, rheology, and boundary conditions. The numerical models show that a growing fault from an analog experiment propagates at depth rather than at the surface and is exposed in later stages of the experiment, and that the wet kaolin clay from the analog experiment is partially decoupled from the steel plate. The numerical models provide the stresses to predict accurate fault growth from the analog experiment and provide the evolution of external work within the fault system. The external work from the numerical models decrease as …
Changing Sediment Transport Processes In Response To Anthropocene Forcing, Brian C. Yellen
Changing Sediment Transport Processes In Response To Anthropocene Forcing, Brian C. Yellen
Doctoral Dissertations
The denudation of uplands and sediment deposition within lowlands comprises one of the most fundamental earth processes. Much like plate tectonics or isostasy, sediment transport runs through nearly every geologic sub-discipline. Its importance extends to other fields as well, such as soil and plant science, archaeology, and engineering. Research in the field of sedimentology remains current, with changes in global sediment transport invoked as a primary line of evidence for the arrival of the Anthropocene, and sedimentary archives frequently employed to evaluate current processes relative to the past. In this vein, my doctoral studies have centered on understanding some aspects …
Geochemical Attributes Of Hydraulically Active Fractures And Their Influence On Groundwater Quality, Amy L. Hudson
Geochemical Attributes Of Hydraulically Active Fractures And Their Influence On Groundwater Quality, Amy L. Hudson
Doctoral Dissertations
This study utilized discrete interval diffusion sampling of a fractured bedrock well completed in schist to investigate if a natural weathering signal can be used to identify hydraulically active fractures. The open borehole well MFS-1, is the focus of the study, which is in close proximity to the recharge zone making it ideal for testing the hypotheses of this study. The hydraulically active fractures of Well MFS-1 were identified, and the dominant mixing force of the water column of the well was determined to be thermal convection in the upper portion of the well and upward gradients. The isotopic data …
Neoarchean Arc Magmatism, Subsequent Collisional Orogenesis, And Paleoproterozoic Disruption Within The Western Churchill Province: Implications For The Growth And Modification Of Lower Continental Crust, Sean P. Regan
Doctoral Dissertations
The growth and modification of continental lithosphere are fundamental geologic processes that have had a profound effect on Earth’s evolution. The lower continental crust can play a myriad of roles pertaining to these processes depending on the strength, age, temperature, and composition of the rocks present. However, the lower continental crust is impossible to sample in-situ, and thus observations of modern lower continental crust are limited to seismic studies and xenolith studies, which provide mere snap shots of the lower crust. High pressure granulite terranes provide 4 dimensional, and spatially resolvable, analogues of lower continental crust. The Athabasca granulite terrane …
Ocean Gateways And Glaciation: Planktic Foraminiferal Records From The Southern Ocean, Equatorial Pacific, And Caribbean, Andrew J. Fraass
Ocean Gateways And Glaciation: Planktic Foraminiferal Records From The Southern Ocean, Equatorial Pacific, And Caribbean, Andrew J. Fraass
Doctoral Dissertations
Ocean gateway changes, once the best mechanism for driving abrupt climatic change, have fallen from favor. They have been largely replaced within the literature by changes in CO2 concentration and orbital forcing. This dissertation looks at three intervals of relative stability (Oligocene), prolonged change (Plio-Pleistocene), or transient events (Oligocene/Miocene boundary) in order to better understand the oceanographic circumstances which govern ‘events’ in the paleoceanographic record. Chapter 1 discusses the chronostratigraphy of Integrated Ocean Drilling Program (IODP) Site U1396 (Expedition 340) in the Caribbean Sea. A combination of paleomagnetostratigraphy, biostratigraphy, astrochronology, and correlation to Marine Isotope Stages (MIS) allows a …
A Paleobathymetric Model And Evolution Of The Brazilian Marginal Basins During The Late Maastrichtian To Eocene Based On Benthic Foraminiferal Biofacies, Renata Moura De Mello
A Paleobathymetric Model And Evolution Of The Brazilian Marginal Basins During The Late Maastrichtian To Eocene Based On Benthic Foraminiferal Biofacies, Renata Moura De Mello
Doctoral Dissertations
Benthic foraminiferal biofacies were delimited for the Maastichtian to upper Eocene of five Brazilian marginal basins (Sergipe-Alagoas, Mucuri, Campos, Santos and Pelotas) and two DSDP Sites 356 and 20C of the western South Altantic. Five biofacies, denoted with letters A to E, were defined using Q-mode cluster analysis and correspondence analysis for all of the 11 sites. The benthic foraminiferal biofacies were used to establish a paleobathymetric and paleoenvironmental model for the Brazilian marginal basins. The model tracks the evolution of the margin as it built seaward and transitioned from abyssal (2000-3000 m) to bathyal (m) and neritic (m) depositional …
Micropaleontology And Isotope Stratigraphy Of The Upper Aptian To Lower Cenomanian (~114-98 Ma) In Odp Site 763, Exmouth Plateau, Nw Australia, Ali Alibrahim
Masters Theses
The biostratigraphy and isotope stratigraphy of the upper Aptian to lower Cenomanian interval including oceanic anoxic events OAE1b, 1c and 1d are investigated in ODP Site 763, drilled on the Exmouth Plateau offshore northwest Australia. Benthic foraminifera suggest that Site 763 was situated in outer neritic to upper bathyal water depths (~150-600 m). OAEs of the Atlantic basin and Tethys are typically associated with organic carbon-rich black shales and δ13C excursions. However, OAEs at this high latitude site correlate with ocean acidification and/or pyrite formation under anoxic conditions rather than black shales. Ocean acidification maybe responsible for sporadic …
Oceanic Anoxia Event 2 (~94 Ma) In The U.S. Western Interior Sea: High Resolution Foraminiferal Record Of The Development Of Anoxia In A Shallow Epicontinental Sea, Amanda L. Parker
Masters Theses
The Upper Cretaceous Tropic Shale of southern Utah captures critical oceanographic changes that occurred during Oceanic Anoxic Event 2 (OAE 2) and the transgression of the Greenhorn Sea. We investigated the response of planktic and benthic foraminifera in a shallow (<100 >m) marine environment stressed by the onset of OAE 2 during the Cenomanian-Turonian boundary (CTB; 93.9 Ma) to determine the oceanographic mechanisms controlling the observed turnovers in the foraminiferal record. This study is based on high-resolution quantitative foraminifera counts and isotope paleoecology (d18O and d13C) from a 40-m outcrop. The OAE 2 interval is identified …
Sources Of Water And Solutes To The Salar De Atacama, Chile: A Coupled Hydrologic, Geochemical, And Groundwater Modeling Study, Lilly G. Corenthal
Sources Of Water And Solutes To The Salar De Atacama, Chile: A Coupled Hydrologic, Geochemical, And Groundwater Modeling Study, Lilly G. Corenthal
Masters Theses
Focused groundwater discharge in endorheic basins provides opportunities to investigate mechanisms for closing hydrologic budgets in arid regions. The Salar de Atacama (SdA), a closed basin in northern Chile, has accumulated over 1800 km3 of halite and a lithium-rich brine since the late Miocene primarily through evapotranspiration of groundwater. The hydrologic balance of SdA and sources of water and solutes required to explain this deposit are not well constrained. An adapted chloride mass balance method drawing on a database of over 200 water sample sites is applied to a remotely-sensed precipitation dataset to estimate spatially-distributed modern groundwater recharge. Comparing …
Supporting New England Communities To Become River-Smart: Policies And Programs That Can Help New England Towns Thrive Despite River Floods, Eve Vogel, Et. Al.
Supporting New England Communities To Become River-Smart: Policies And Programs That Can Help New England Towns Thrive Despite River Floods, Eve Vogel, Et. Al.
Water Reports
This report aims to help New England’s communities and their residents, as well as the governments thatserve them, to better deal with and adjust to riverfloods. It points to practical policy solutions at federal, state and regional levels that can support NewEngland communities to become what we call river-smart.
Bering Sea Surface Water Conditions During Marine Isotope Stages 12 To 10 At Navarin Canyon (Iodp Site U1345), Beth E. Caissie, Julie Brigham-Grette, Mea S. Cook, Elena Colmenero-Hidalgo
Bering Sea Surface Water Conditions During Marine Isotope Stages 12 To 10 At Navarin Canyon (Iodp Site U1345), Beth E. Caissie, Julie Brigham-Grette, Mea S. Cook, Elena Colmenero-Hidalgo
Geosciences Department Faculty Publication Series
Records of past warm periods are essential for understanding interglacial climate system dynamics. Marine Isotope Stage 11 occurred from 425 to 394 ka, when global ice volume was the lowest, sea level was the highest, and terrestrial temperatures were the warmest of the last 500 kyr. Because of its extreme character, this interval has been considered an analog for the next century of climate change. The Bering Sea is ideally situated to record how opening or closing of the Pacific–Arctic Ocean gateway (Bering Strait) impacted primary productivity, sea ice, and sediment transport in the past; however, little is known about …
Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert Deconto
Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert Deconto
Geosciences Department Faculty Publication Series
A 3-D hybrid ice-sheet model is applied to the last deglacial retreat of the West Antarctic Ice Sheet over the last ∼ 20 000 yr. A large ensemble of 625 model runs is used to calibrate the model to modern and geologic data, including reconstructed grounding lines, relative sea-level records, elevation–age data and uplift rates, with an aggregate score computed for each run that measures overall model–data misfit. Two types of statistical methods are used to analyze the large-ensemble results: simple averaging weighted by the aggregate score, and more advanced Bayesian techniques involving Gaussian process-based emulation and calibration, and Markov …
Stream Power: Origins, Geomorphic Applications, And Gis Procedures, John Gartner
Stream Power: Origins, Geomorphic Applications, And Gis Procedures, John Gartner
Water Publications
Stream power is a widely used parameter to investigate, engineer, and manage river systems.The varied uses ofstream power are increasing as it becomes easier to derive stream power using remotely sensed data coupled with Geographic Information Systems (GIS) and improved computational power and technology. This document was created to provide clarity to researchers and practitioners using stream power in their work. It includes a review of the physical basis, terminology, and applications of stream power; an examination of the many considerations and techniques for computing stream power; and a step by step example workflow to compute stream power using GIS …