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2012

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Articles 31 - 60 of 126

Full-Text Articles in Physical Sciences and Mathematics

A Mineralogical Textural And Chemical Characterization Of A Hypothesized Kimberlite At White Mountain, Sunlight Basin, Wyoming, Stuart Kenderes May 2012

A Mineralogical Textural And Chemical Characterization Of A Hypothesized Kimberlite At White Mountain, Sunlight Basin, Wyoming, Stuart Kenderes

Mahurin Honors College Capstone Experience/Thesis Projects

Geologists have examined the causes and mechanisms responsible for the Heart Mountain detachment for over a century with much debate and discussion. White Mountain is a part of the upper plate, which was emplaced during the detachment event. Within White Mountain, there exist several andesitic dikes and carbonate ultra-cataclasite injectites, which were integral in the emplacement of the Heart Mountain detachment. This research involves the characterization and identification of an enigmatic vertical outcropping of brecciated rock located on White Mountain, Sunlight Basin, Wyoming, which was originally interpreted as a kimberlite. Samples were collected for geochemical and textural comparison, and cut …


Heterogeneous Deformation Of Gabbroic Rocks, Calvin Mako May 2012

Heterogeneous Deformation Of Gabbroic Rocks, Calvin Mako

Honors College

The Grenville province is the exhumed remains of a more than 1 billion year old orogen. Mid to lower crustal rocks of this orogen are now exposed at the surface, affording the opportunity to examine deeper crustal processes during orogeny. I have studied an outcrop of anorthositic gabbro from the Central Metasedimentary Belt boundary thrust zone (CMBbtz) in the Grenville province of southern Ontario. The CMBbtz is a region that separates two major lithotectonic domains of this part of the Grenville province and is thought to have accommodated large scale thrusting in the mesoproterozoic era. The CMBbtz comprises large crystalline …


Bulk Rock Composition And Geochemistry Of Olivine-Hosted Melt Inclusions In The Grey Porri Tuff And Selected Lavas Of The Monte Dei Porri Volcano, Salina, Aeolian Islands, Southern Italy., Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy Apr 2012

Bulk Rock Composition And Geochemistry Of Olivine-Hosted Melt Inclusions In The Grey Porri Tuff And Selected Lavas Of The Monte Dei Porri Volcano, Salina, Aeolian Islands, Southern Italy., Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy

All Faculty Scholarship for the College of the Sciences

The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions occurred between 60 ka and 30 ka, following a period of approximately 60,000 years of repose. The bulk rock composition of the Monte dei Porri products range from basaltic-andesite scoria to andesitic pumice in the Grey Porri Tuff (GPT), with the Monte dei Porri lavas having basaltic-andesite compositions. The typical …


Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce Apr 2012

Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce

College of Arts and Sciences Poster Presentations

Soil carbon is the third largest carbon pool within the global carbon cycle; however, soil carbon amounts are not well quantified, and exchange rates of soil carbon are not well understood. Soil carbon can be divided into organic carbon and inorganic carbon, where inorganic carbon (pedogenic carbonate) is precipitated during soil formation and accumulates over time in semi-arid and arid environments. Calcic soils within the semiarid regions of the Boise Valley result from active pedogenic accumulation of secondary CaCO3 resulting in prominent 'caliche' layers in soils formed on many of the Boise River terraces. The larger goals of this …


Stratigraphy, Geochronology And Detrital Zircon Provenance Of Two Silicic Ash Layers At Hagerman Fossil Beds National Monument, Idaho, Susan K. Birnbaum, Brock Lipple Apr 2012

Stratigraphy, Geochronology And Detrital Zircon Provenance Of Two Silicic Ash Layers At Hagerman Fossil Beds National Monument, Idaho, Susan K. Birnbaum, Brock Lipple

College of Arts and Sciences Poster Presentations

Hagerman Fossil Beds National Monument (HAFO) is home to the world-famous Hagerman Horse Quarry. This site gives important insight into Pliocene age paleontology. Absolute ages of this site have been elusive, although researchers have assumed the site to be around 3.2 Ma. This study sought to determine more precise ages for the previously documented Hagerman Horse Quarry and Peters Gulch ash layers at HAFO thereby defining a more specific date for the Hagerman fossil assemblage, and to describe and interpret their sedimentary horizons. Detailed stratigraphic columns were created to describe sedimentary layers and establish marker beds. The sedimentology and stratigraphy …


Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell Apr 2012

Plankton Evolution Driven By Paleoceanographic Change: Prediscosphaera From The Mid-Cretaceous In The Western North Atlantic, Kristen L. Mitchell

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Well-preserved nannofossil assemblages in late Albian and Cenomanian hemipelagic sections from Ocean Drilling Program (ODP) Leg 171B preserve a record of the early history and adaptive radiation of the calcareous nannofossil genus Prediscosphaera. There was a significant rise in the abundance of the genus (from an average of 2% in the early late Albian to about 6% in the latest Albian and Cenomanian. This rise, and other shorter term pulses of increased generic abundance, corresponds to black shale deposition episodes. Twelve distinct morphotypes that were derived from the long-ranging Prediscosphera columnata and Prediscosphaera spinosa, are recognized and differentiated …


Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui Apr 2012

Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui

Department of Earth and Atmospheric Sciences: Faculty Publications

This paper provides documentation of unexpectedly high-reservoir-quality glaciomarine sands found in the Cenozoic succession beneath McMurdo Sound, Antarctica, as an analogue study for evaluations of hydrocarbon prospectivity in basins elsewhere. The Oligocene to Lower Miocene succession of the Victoria Land Basin, an extant portion of the West Antarctic Rift System, comprises diamictites, mudrocks, and sandstones with minor conglomerates. These lithologies are arranged in repetitive stacking patterns (cycles), interpreted to record repeated advance and retreat of glaciers into and out of the basin, with attendant eustatic and isostatic effects. Phases of ice retreat within the cycles comprise an array of mudrocks, …


Wilson Cycles, Tectonic Inheritance, And Rifting Of The North American Gulf Of Mexico Continental Margin, Audrey D. Huerta, Dennis L. Harry Apr 2012

Wilson Cycles, Tectonic Inheritance, And Rifting Of The North American Gulf Of Mexico Continental Margin, Audrey D. Huerta, Dennis L. Harry

Geological Sciences Faculty Scholarship

The tectonic evolution of the North American Gulf of Mexico continental margin is characterized by two Wilson cycles, i.e., repeated episodes of opening and closing of ocean basins along the same structural trend. This evolution includes (1) the Precambrian Grenville orogeny; (2) formation of a rift-transform margin during late Precambrian opening of the Iapetus Ocean; (3) the late Paleozoic Ouachita orogeny during assembly of Pangea; and (4) Mesozoic rifting during opening of the Gulf of Mexico. Unlike the Atlantic margins, where Wilson cycles were first recognized, breakup in the Gulf of Mexico did not initially focus within the orogen, but …


Late Holocene Rupture History Of The Alpine Fault In South Westland, New Zealand, Kelvin Berryman, Alan Cooper, Richard Norris, Pilar Villamor, Rupert Sutherland, Trevor Wright, Elizabeth R. Schermer, Robert Langridge, Glenn Biasi Apr 2012

Late Holocene Rupture History Of The Alpine Fault In South Westland, New Zealand, Kelvin Berryman, Alan Cooper, Richard Norris, Pilar Villamor, Rupert Sutherland, Trevor Wright, Elizabeth R. Schermer, Robert Langridge, Glenn Biasi

Geology Faculty Publications

Abstract Strata and fault relationships revealed in five trenches excavated across the recent trace of the Alpine fault at the Haast, Okuru, and Turnbull Rivers, South Westland, New Zealand, record the three most recent surface-faulting events. Using back-stripping techniques to remove the three faulting events and the sedimentary units associated with the faulting restores the cross-sections to gravel-bed floodplains at the Haast and Okuru Rivers, at about A.D. 750. Horizontal and vertical offsets of stream channels and terrace risers reveal characteristic displacements of about 8–9 m dextral and up to 1 m vertical per event. Cumulative dextral displacement is 25 …


Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall Mar 2012

Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall

United States Geological Survey: Staff Publications

Stable 13C, 15N, and 34S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee sub adults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than immigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of …


Habitat And Prey Availability Attributes Associated With Juvenile And Early Adult Pallid Sturgeon Occurrence In The Missouri River, Usa, Bryan D. Spindler, Steven R. Chipps, Robert A. Klumb, Brian D. S. Graeb, Michael C. Wimberly Mar 2012

Habitat And Prey Availability Attributes Associated With Juvenile And Early Adult Pallid Sturgeon Occurrence In The Missouri River, Usa, Bryan D. Spindler, Steven R. Chipps, Robert A. Klumb, Brian D. S. Graeb, Michael C. Wimberly

United States Geological Survey: Staff Publications

The pallid sturgeon Scaphirhynchus albus is a federally endangered species native to the Missouri and lower Mississippi Rivers, USA. As part of recovery efforts, over 360 000 pallid sturgeon have been stocked into the Missouri River since 1994, and a standardized, long-term monitoring program was initiated in 2003. Understanding the distribution and habitat requirements of juvenile and early adult pallid sturgeon (fork length <720 mm, age <10 yr) is an important goal of the monitoring and recovery programs. In this study, we collected information on habitat characteristics and prey availability from the upper Missouri River along the Nebraska-South Dakota border and compared these attributes between capture (present) and non-capture (absent) locations (N = 59). To evaluate the relative influence of habitat and prey availability on pallid sturgeon occurrence, we examined several candidate models using an informationtheoretic approach. A prey availability model had the most support and included site-specific information on Diptera and Ephemeroptera abundance. A habitat-based model showed that juveniles and early adults were found in relatively deeper water and avoided areas where bottom velocities were greater than 1.2 m s−1. Although not as well supported as the prey-effects model (evidence ratio = 6.4), habitat features also provided a plausible model for predicting occurrence. The models developed here could be used to evaluate pallid sturgeon habitat potential in the Missouri River basin and help guide future monitoring and conservation management of this endangered species.


Heterogeneous Detection Probabilities For Imperiled Missouri River Fishes: Implications For Large-River Monitoring Programs, Joshua T. Schloesser, Craig P. Paukert, Wyatt J. Doyle, Tracy D. Hill, Kirk D. Steffensen, Vince H. Travnichek Mar 2012

Heterogeneous Detection Probabilities For Imperiled Missouri River Fishes: Implications For Large-River Monitoring Programs, Joshua T. Schloesser, Craig P. Paukert, Wyatt J. Doyle, Tracy D. Hill, Kirk D. Steffensen, Vince H. Travnichek

United States Geological Survey: Staff Publications

Occupancy modeling was used to determine (1) if detection probabilities (p) for 7 regionally imperiled Missouri River fishes (Scaphirhynchus albus, Scaphirhynchus platorynchus, Cycleptus elongatus, Sander canadensis, Macrhybopsis aestivalis, Macrhybopsis gelida, and Macrhybopsis meeki) differed among gear types (i.e. stationary gill nets, drifted trammel nets, and otter trawls), and (2) how detection probabilities were affected by habitat (i.e. pool, bar, and open water), longitudinal position (five 189 to 367 rkm long segments), sampling year (2003 to 2006), and season (July 1 to October 30 and October 31 to June 30). Adult, large-bodied fishes were …


Projecting Changes In Extreme Precipitation In The Midwestern United States Using North American Regional Climate Change Assessment Program (Narccap) Regional Climate Models, Shuang-Ye Wu Mar 2012

Projecting Changes In Extreme Precipitation In The Midwestern United States Using North American Regional Climate Change Assessment Program (Narccap) Regional Climate Models, Shuang-Ye Wu

Geology Faculty Publications

Based on the physics of global circulation, many expect an enhanced greenhouse effect to lead to a more active hydrological cycle with more precipitation on average (Hennessy et al. 1997). This expected increase has been found in observations (Zhang et al. 2007) and has also been suggested by climate models, although these models are not consistent with respect to the spatial and temporal variability about this change. An increase in mean precipitation depth, assuming no change in the shape of the frequency distribution, would imply an increased frequency of heavy-precipitation events. However, some studies (Hennessy et al. 1997, Allen and …


Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia Mar 2012

Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia

TREC Final Reports

Geologic hazards such as coastal erosion, landslides, seismic loading, etc. constantly threaten public highway construction and maintenance. Repeat surveys using terrestrial laser scanning (TLS, ground-based LiDAR) enable rapid 3D data acquisition to map, see, analyze, and understand the processes generating such problems. Previously, change detection and analysis between scan surveys was conducted during post-processing upon return to the office, instead of while collecting data in the field. Change detection in the field improves the effectiveness and efficiency of the field investigation. We have developed a new algorithm that quickly geo-references scans upon field acquisition and simultaneously performs change detection by …


Geodetic Constraints On San Francisco Bay Area Fault Slip Rates And Potential Seismogenic Asperities On The Partially Creeping Hayward Fault, Eileen L. Evans, John P. Loveless, Brendan J. Meade Mar 2012

Geodetic Constraints On San Francisco Bay Area Fault Slip Rates And Potential Seismogenic Asperities On The Partially Creeping Hayward Fault, Eileen L. Evans, John P. Loveless, Brendan J. Meade

Geosciences: Faculty Publications

The Hayward fault in the San Francisco Bay Area (SFBA) is sometimes considered unusual among continental faults for exhibiting significant aseismic creep during the interseismic phase of the seismic cycle while also generating sufficient elastic strain to produce major earthquakes. Imaging the spatial variation in interseismic fault creep on the Hayward fault is complicated because of the interseismic strain accumulation associated with nearby faults in the SFBA, where the relative motion between the Pacific plate and the Sierra block is partitioned across closely spaced subparallel faults. To estimate spatially variable creep on the Hayward fault, we interpret geodetic observations with …


Response Of A Carbonate Platform To The Cenomanian-Turonian Drowning And Oae 2: A Case Study From The Adriatic Platform (Dalmatia, Croatia), Tvrtko Korbar, B. Glumac, Blanka Cvetko Tesovic, Sarah B. Cadieux Mar 2012

Response Of A Carbonate Platform To The Cenomanian-Turonian Drowning And Oae 2: A Case Study From The Adriatic Platform (Dalmatia, Croatia), Tvrtko Korbar, B. Glumac, Blanka Cvetko Tesovic, Sarah B. Cadieux

Geosciences: Faculty Publications

Global perturbations during the Cenomanian–Turonian boundary (CTB) interval and the Oceanic Anoxic Event 2 (OAE 2) represent one of the most extensively studied past environmental changes. To explore the response of various carbonate-platform depositional systems to such major environmental perturbations, strata of the intra-Tethyan Adriatic carbonate platform (sensu stricto) from the island of Bracˇ (Adriatic Sea, Croatia) provide excellent exposures and a previously well-established Upper Cretaceous lithostratigraphic framework. Within this context, this study integrated lithostratigraphy, biostratigraphy, and chemostratigraphy to describe a drowned-platform succession underlain and overlain by peritidal carbonates. Carbon-isotope stratigraphy of this succession revealed a shift towards positive d13C …


Particle Transport Over Rough Hillslope Surfaces By Dry Ravel: Experiments And Simulations With Implications For Nonlocal Sediment Flux, Emmanuel Gabet, Morgan Mendoza Feb 2012

Particle Transport Over Rough Hillslope Surfaces By Dry Ravel: Experiments And Simulations With Implications For Nonlocal Sediment Flux, Emmanuel Gabet, Morgan Mendoza

Faculty Publications

Past studies of hillslope evolution have typically assumed that soil creep processes are governed by a linear relationship between local hillslope angle and transport distance. The assumption of “linear diffusion” has fallen out of favor because, when coupled with an expression of mass continuity, it yields unrealistic hillslope profiles. As a consequence, a better understanding of the mechanics of sediment transport is needed. Here we report results from a series of flume experiments performed to investigate sediment transport by dry ravel, a common soil creep process in arid and semiarid environments. We find that, at gentle slopes, transport distances follow …


Mapview And Cross Section Animations, Jason Luke Feb 2012

Mapview And Cross Section Animations, Jason Luke

Faculty Publications

Movie 1: A series of time slices animated through the amplitude volume. Movie 2: A series of time slices animated through the semblance volume. Movie 3: Cross section animation from SW-NE through the amplitude volume. Movie 4: Cross section animation from SW-NE through the semblance volume.


Projected Surface Raidiative Forcing Due To 2000-2050 Land-Cover Land-Use Albedo Change Over The Eastern United States, Christoper A. Barnes, David P. Roy, Thomas R. Loveland Feb 2012

Projected Surface Raidiative Forcing Due To 2000-2050 Land-Cover Land-Use Albedo Change Over The Eastern United States, Christoper A. Barnes, David P. Roy, Thomas R. Loveland

GSCE Faculty Publications

Satellite-derived contemporary land-cover land-use (LCLU) and albedo data and modeled future LCLU are used to study the impact of LCLU change from 2000 to 2050 on surface albedo and radiative forcing for 19 ecoregions in the eastern United States. The modeled 2000–2050 LCLU changes indicate a future decrease in both agriculture and forested land and an increase in developed land that induces ecoregion radiative forcings ranging from −0.175 to 0.432 W m−2 driven predominately by differences in the area and type of LCLU change. At the regional scale, these projected LCLU changes induce a net negative albedo decrease (−0.001) and …


Sensitivity Analysis Of The Gems Soil Organic Carbon Model To Land Cover Land Use Classification Uncertainties Under Different Climate Scenarios In Senegal, Amadou M. Dieye, David P. Roy, N. P. Hanan, S. Lui, M. Hansen, A. Toure Feb 2012

Sensitivity Analysis Of The Gems Soil Organic Carbon Model To Land Cover Land Use Classification Uncertainties Under Different Climate Scenarios In Senegal, Amadou M. Dieye, David P. Roy, N. P. Hanan, S. Lui, M. Hansen, A. Toure

GSCE Faculty Publications

Spatially explicit land cover land use (LCLU) change information is needed to drive biogeochemical models that simulate soil organic carbon (SOC) dynamics. Such information is increasingly being mapped using remotely sensed satellite data with classification schemes and uncertainties constrained by the sensing system, classification algorithms and land cover schemes. In this study, automated LCLU classification of multi-temporal Landsat satellite data were used to assess the sensitivity of SOC modeled by the Global Ensemble Biogeochemical Modeling System (GEMS). The GEMS was run for an area of 1560km2 in Senegal under three climate change scenarios with LCLU maps generated using different Landsat …


Thermal Tracking Of Meltwater Retention In Greenland’S Accumulation Area, Neil F. Humphrey, Joel T. Harper, W. Tad Pfeffer Jan 2012

Thermal Tracking Of Meltwater Retention In Greenland’S Accumulation Area, Neil F. Humphrey, Joel T. Harper, W. Tad Pfeffer

Geosciences Faculty Publications

Poorly understood processes controlling retention of meltwater in snow and firn have important implications for Greenland Ice Sheet’s mass balance and flow dynamics. Here we present results from a 3 year (2007-2009) field campaign studying firn thermal profiles and density structure along an 85 km transect of the percolation zone of west Greenland. We installed one or two thermistor strings at 14 study sites, each string having 32 sensors spaced between 0 and 10 m depth. Data from our network of over 500 sensors were collected at 15-60 min intervals for 1-2 years, thereby recording the thermal signature of meltwater …


Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson Jan 2012

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel T. Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson

Geosciences Faculty Publications

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland’s percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt.We used geoader to investigate firn density variations with depth along an about 70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection travel times picked from common midpoint gathers. We followed a procedure designed to find the simplest …


Allen-Carlson, Dawn Elaine (Fa 34), Manuscripts & Folklife Archives Jan 2012

Allen-Carlson, Dawn Elaine (Fa 34), Manuscripts & Folklife Archives

FA Finding Aids

Finding aid only for Folklife Archives Project 34. [Dr. Joe Daugherty: collector] Oral history project completed by Dawn Elaine Allen-Carlson concerning the collections of Daugherty for a folk studies class at Western Kentucky University. Contains data sheet, journal, 2 indices, tape summary and transcription.


How Does Hydropeaking Alter The Hydrology Of A River Reach? A Combined Water Budget, Modeling, And Field Observation Study. Deerfield River, Massachusetts, Brian C. Yellen Jan 2012

How Does Hydropeaking Alter The Hydrology Of A River Reach? A Combined Water Budget, Modeling, And Field Observation Study. Deerfield River, Massachusetts, Brian C. Yellen

Masters Theses 1911 - February 2014

Hydroelectric releases on the Deerfield River in northwestern Massachusetts affect surface water-groundwater interactions there by daily reversing the head gradient between river and groundwater. Artificially elevated stage drives river water into the riparian aquifer. Water budget analysis indicates that roughly 10% of this bank-stored water is permanently lost from the river system in a 19.5 km reach, likely as a result of transpiration by bank vegetation.

Field observations as well as two-dimensional modeling results show that water losses are not uniform throughout the study reach. Riparian aquifer transmissivity in river sub-reaches largely determines the magnitude of surface water-groundwater exchange as …


Evolution Of Volatile Content Of The Parent Magma Of The 1875 Eruption Of Askja Volcano, Iceland, Heather A. Clark Jan 2012

Evolution Of Volatile Content Of The Parent Magma Of The 1875 Eruption Of Askja Volcano, Iceland, Heather A. Clark

Masters Theses 1911 - February 2014

The bulk of the eruption of Askja in north central Iceland on March 28-29 1875 consisted of a plinian eruption that lasted 6-7 hours, produced 0.2 km3 of ash and rhyolitic pumice, and created a surge and partially welded ash/pumice fall deposit that crops out on the shore of the modern caldera lake (Sparks et al. 1981). We evaluate the volatile budget of the magma during the eruption and focus on water concentration in glass fragments and shards, glass adjacent to crystals, and melt inclusions (MIs). Sparks et al. (1981) estimated the gas exit velocity at the vent was …


A Paleoclimate Modeling Experiment To Calculate The Soil Carbon Respiration Flux For The Paleocene-Eocene Thermal Maximum, David M. Tracy Jan 2012

A Paleoclimate Modeling Experiment To Calculate The Soil Carbon Respiration Flux For The Paleocene-Eocene Thermal Maximum, David M. Tracy

Masters Theses 1911 - February 2014

The Paleocene-Eocene Thermal Maximum (PETM) (55 million years ago) stands as the largest in a series of extreme warming (hyperthermal) climatic events, which are analogous to the modern day increase in greenhouse gas concentrations. Orbitally triggered (Lourens et al., 2005, Galeotti et al., 2010), the PETM is marked by a large (-3‰) carbon isotope excursion (CIE). Hypothesized to be methane driven, Zeebe et al., (2009) noted that a methane based release would only account for 3.5°C of warming. An isotopically heavier carbon, such as that of soil and C3 plants, has the potential to account for the …


Characterization Of Damage Zones Associated With Laboratory Produced Natural Hydraulic Fractures, Erin Bradley Jan 2012

Characterization Of Damage Zones Associated With Laboratory Produced Natural Hydraulic Fractures, Erin Bradley

Masters Theses 1911 - February 2014

Both joint sets and fault-related fractures serve as important conduits for fluid flow. In the former case, they can strongly influence both permeability and permeability anisotropy, with implications for production of water, hydrocarbons and contaminant transport. The latter can affect issues of fluid flow, such as whether a given fault seals or leaks, and fault mechanics. These fractures are commonly interpreted as Natural Hydraulic Fractures (NHFs), i.e., mode 1 fractures produced when pore fluid pressure exceeds the tensile strength of the rock. Various mathematical models have been a rich source of hypotheses to explain the formation and propagation of NHFs, …


Fractures Of The Dammam Dome Carbonate Outcrops: Their Characterization, Development, And Implications For Subsurface Reservoirs, Mohammed M. Al-Fahmi Jan 2012

Fractures Of The Dammam Dome Carbonate Outcrops: Their Characterization, Development, And Implications For Subsurface Reservoirs, Mohammed M. Al-Fahmi

Masters Theses 1911 - February 2014

The exposed Tertiary carbonates of the Dammam Dome present an opportunity to study fractures in outcrops within the oil-producing region of Eastern Saudi Arabia. The study focuses on: 1) the characterization of fractures, 2) interpretation of their fracturing mechanism, and 3) the implications for the deep carbonate reservoirs of the Dammam Dome. The characterization of the outcrop fractures is integrated with structural analysis of the near-surface horizons mapped from reflection seismic and well data. Fractures are observed within all exposed carbonate units, but predominantly within the widely exposed Middle Rus unit. The fractures are opening-mode, bed-bound joints that form orthogonal …


Interseismic Strain Accumulation Along The Western Boundary Of The Indian Subcontinent, Walter Szeliga, Roger Bilham, Din Mohammad Kakar, Sarosh H. Lodi Jan 2012

Interseismic Strain Accumulation Along The Western Boundary Of The Indian Subcontinent, Walter Szeliga, Roger Bilham, Din Mohammad Kakar, Sarosh H. Lodi

Faculty Scholarship for the Cascadia Hazards Institute

Despite an overall sinistral slip rate of approximately 3 cm/yr, few major earthquakes have occurred in the past 200 years along the Chaman fault system, the western boundary of the India Plate with the Eurasia Plate. GPS and InSAR data reported here indicate sinistral shear velocities of 8-17 mm/yr across the westernmost branches of the fault system, suggesting that a significant fraction of the plate boundary slip is distributed in the fold and fault belt to the east. At its southernmost on-land segment, near the triple junction between the Arabia, Eurasia, and India Plates, we find the velocity across the …


Paleomagnetism Of Cascade Range Pleistocene Lava Flows Near Mckenzie Bridge, Oregon, Chelsea Jaeger Jan 2012

Paleomagnetism Of Cascade Range Pleistocene Lava Flows Near Mckenzie Bridge, Oregon, Chelsea Jaeger

Summer Research

The purpose of this study is to examine geomagnetic field behavior recorded in a series of Pleistocene lava flows located near McKenzie Bridge, Oregon. Twenty-four sites, each consisting of at least ten samples were collected during July of 2011 and 2012. Alternating field (AF) and thermal demagnetization studies reveal normal, reversed, and possibly transitional polarities. Thermal demagnetization studies indicate the bulk of the magnetic signal is held in low titanium magnetite. Additional AF and thermal analysis is required to confirm transitional directions. In addition, polished sections will be prepared for optical examination to confirm the magnetic mineralogy of the samples.