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Articles 331 - 360 of 667

Full-Text Articles in Earth Sciences

Characterizing Coseismic Ionospheric Disturbance For Surface-Rupturing Earthquakes, Rebekah Faith Lee Dec 2017

Characterizing Coseismic Ionospheric Disturbance For Surface-Rupturing Earthquakes, Rebekah Faith Lee

Boise State University Theses and Dissertations

Coseismic ionospheric disturbances (CID) are commonly identified using global navigation space system (GNSS) satellites. Little research, however, has focused on using total electron content (TEC) observations to characterize acoustic sources on Earth's surface. For this thesis, I investigate the applicability of an analytical method to invert the TEC for the acoustic wave. The inversion is based on the modeling of a transfer function. Deconvolving the TEC by the transfer function gives the acoustic wave. Inverting for the acoustic wave in this way would remove phase differences in the TEC created by atmospheric-ionospheric coupling. I test the assumption in the model …


Seismic Refraction And Electrical Resistivity Tests For Fracture Induced Anisotropy In A Mountain Watershed, Aida Mendieta Dec 2017

Seismic Refraction And Electrical Resistivity Tests For Fracture Induced Anisotropy In A Mountain Watershed, Aida Mendieta

Boise State University Theses and Dissertations

The critical zone (CZ) is the earth’s layer where water, air, rock, and life meet. It is the zone with which humans interact most. The National Research council (2001) defines the CZ as a “heterogeneous, near surface environment in which complex interactions involving rock, soil, water, air, and living organisms regulate the natural habitat and determine the availability of life sustaining resources”. The CZ may extend roughly from the top of the vegetation canopy to the deepest part of the rock column where meteoric water circulates – this is often in the 10 – 30 m range. The upper 1-2 …


Application Of Hydrogeophysical Imaging In The Reynolds Creek Critical Zone Observatory, Travis Nielson Dec 2017

Application Of Hydrogeophysical Imaging In The Reynolds Creek Critical Zone Observatory, Travis Nielson

Boise State University Theses and Dissertations

The critical zone is defined as the upper most portion of the crust extending from the top of unweathered bedrock to the top of the vegetation canopy. It is the zone in which inorganic rock is transformed into biologically useful soils and saprolites in a process termed weathering. Because the critical zone is the connection between the subsurface and surface it plays a role in a wide variety of biological, hydrologic, and climatic processes. Understanding the critical zone though is inherently difficult because its scale and heterogeneity often means direct sampling methods, e.g. soil pits and cores, under represent the …


Deriving Landscape-Scale Vegetation Cover And Aboveground Biomass In A Semi-Arid Ecosystem Using Imaging Spectroscopy, Andrew Poley Dec 2017

Deriving Landscape-Scale Vegetation Cover And Aboveground Biomass In A Semi-Arid Ecosystem Using Imaging Spectroscopy, Andrew Poley

Boise State University Theses and Dissertations

Environmental disturbances in semi-arid ecosystems have highlighted the need to monitor current and future vegetation conditions across the landscape. Imaging spectroscopy provide the necessary information to derive vegetation characteristics at high-spatial resolutions across large geographic areas. The work of this thesis is divided into two sections focused on using imaging spectroscopy to estimate and classify vegetation cover, and approximate aboveground biomass in a semi-arid ecosystem.

The first half of this thesis assesses the ability of imaging spectroscopy to derive vegetation classes and their respective cover across large environmental gradients and ecotones often associated with semi-arid ecosystems. Optimal endmember selection and …


Mapping Soil Organic Carbon (Soc) In A Semi-Arid Mountainous Watershed Using Variables From Hyperspectral, Lidar And Traditional Datasets, Ryan Matthew Will Dec 2017

Mapping Soil Organic Carbon (Soc) In A Semi-Arid Mountainous Watershed Using Variables From Hyperspectral, Lidar And Traditional Datasets, Ryan Matthew Will

Boise State University Theses and Dissertations

Quantifying soil organic carbon (SOC) in complex terrain is challenging due to its high spatial variability. Generally, limited discrete observations of SOC data are used to develop spatially distributed maps of SOC by developing quantitative relationships between SOC and available spatially distributed variables. In many ecosystems, remotely sensed information on aboveground vegetation can be used to predict belowground carbon stocks. In this research, we developed maps of SOC across a semi-arid watershed based on discrete field observations and modeling using a suite of variables inclusive of hyperspectral and lidar datasets; these observations provide insights into the controls on soil carbon …


Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson Oct 2017

Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Mechanisms that produce seismic and acoustic wavefields near rivers are poorly understood because of a lack of observations relating temporally dependent river conditions to the near-river seismoacoustic fields. This controlled study at the Harry W. Morrison Dam (HWMD) on the Boise River, Idaho, explores how temporal variation in fluvial systems affects surrounding acoustic and seismic fields. Adjusting the configuration of the HWMD changed the river bathymetry and therefore the form of the standing wave below the dam. The HWMD was adjusted to generate four distinct wave regimes that were parameterized through their dimensionless Froude numbers (Fr) and …


Using Isotopes To Constrain Water Flux And Age Estimates In Snow-Influenced Catchments Using The Starr (Spatially Distributed Tracer-Aided Rainfall–Runoff) Model, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon, Chris Soulsby Oct 2017

Using Isotopes To Constrain Water Flux And Age Estimates In Snow-Influenced Catchments Using The Starr (Spatially Distributed Tracer-Aided Rainfall–Runoff) Model, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon, Chris Soulsby

Geosciences Faculty Publications and Presentations

Tracer-aided hydrological models are increasingly used to reveal fundamentals of runoff generation processes and water travel times in catchments. Modelling studies integrating stable water isotopes as tracers are mostly based in temperate and warm climates, leaving catchments with strong snow influences underrepresented in the literature. Such catchments are challenging, as the isotopic tracer signals in water entering the catchments as snowmelt are typically distorted from incoming precipitation due to fractionation processes in seasonal snowpack.

We used the Spatially distributed Tracer-Aided Rainfall– Runoff (STARR) model to simulate fluxes, storage, and mixing of water and tracers, as well as estimating water ages …


Assessing A Multi-Platform Data Fusion Technique In Capturing Spatiotemporal Dynamics Of Heterogeneous Dryland Ecosystems In Topographically Complex Terrain, Peter J. Olsoy, Jessica Mitchell, Nancy F. Glenn, Alejandro N. Flores Oct 2017

Assessing A Multi-Platform Data Fusion Technique In Capturing Spatiotemporal Dynamics Of Heterogeneous Dryland Ecosystems In Topographically Complex Terrain, Peter J. Olsoy, Jessica Mitchell, Nancy F. Glenn, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

Water-limited ecosystems encompass approximately 40% of terrestrial land mass and play a critical role in modulating Earth’s climate and provisioning ecosystem services to humanity. Spaceborne remote sensing is a critical tool for characterizing ecohydrologic patterns and advancing the understanding of the interactions between atmospheric forcings and ecohydrologic responses. Fine to medium scale spatial and temporal resolutions are needed to capture the spatial heterogeneity and the temporally intermittent response of these ecosystems to environmental forcings. Techniques combining complementary remote sensing datasets have been developed, but the heterogeneous nature of these regions present significant challenges. Here we investigate the capacity of one …


Lidar Aboveground Vegetation Biomass Estimates In Shrublands: Prediction, Uncertainties And Application To Coarser Scales, Aihua Li, Shital Dhakal, Nancy F. Glenn, Lucas P. Spaete Sep 2017

Lidar Aboveground Vegetation Biomass Estimates In Shrublands: Prediction, Uncertainties And Application To Coarser Scales, Aihua Li, Shital Dhakal, Nancy F. Glenn, Lucas P. Spaete

Geosciences Faculty Publications and Presentations

Our study objectives were to model the aboveground biomass in a xeric shrub-steppe landscape with airborne light detection and ranging (Lidar) and explore the uncertainty associated with the models we created. We incorporated vegetation vertical structure information obtained from Lidar with ground-measured biomass data, allowing us to scale shrub biomass from small field sites (1 m subplots and 1 ha plots) to a larger landscape. A series of airborne Lidar-derived vegetation metrics were trained and linked with the field-measured biomass in Random Forests (RF) regression models. A Stepwise Multiple Regression (SMR) model was also explored as a comparison. Our results …


A Machine Learning Approach To Estimation Of Downward Solar Radiation From Satellite-Derived Data Products: An Application Over A Semi-Arid Ecosystem In The U.S., Qingtao Zhou, Alejandro Flores, Nancy F. Glenn, Reggie Walters, Bangshuai Han Aug 2017

A Machine Learning Approach To Estimation Of Downward Solar Radiation From Satellite-Derived Data Products: An Application Over A Semi-Arid Ecosystem In The U.S., Qingtao Zhou, Alejandro Flores, Nancy F. Glenn, Reggie Walters, Bangshuai Han

Geosciences Faculty Publications and Presentations

Shortwave solar radiation is an important component of the surface energy balance and provides the principal source of energy for terrestrial ecosystems. This paper presents a machine learning approach in the form of a random forest (RF) model for estimating daily downward solar radiation flux at the land surface over complex terrain using MODIS (MODerate Resolution Imaging Spectroradiometer) remote sensing data. The model-building technique makes use of a unique network of 16 solar flux measurements in the semi-arid Reynolds Creek Experimental Watershed and Critical Zone Observatory, in southwest Idaho, USA. Based on a composite RF model built on daily observations …


Spreading Rate-Dependent Variations In Crystallization Along The Global Mid-Ocean Ridge System, V. Dorsey Wanless, Mark D. Behn Aug 2017

Spreading Rate-Dependent Variations In Crystallization Along The Global Mid-Ocean Ridge System, V. Dorsey Wanless, Mark D. Behn

Geosciences Faculty Publications and Presentations

We investigate crustal accretion at mid-ocean ridges by combining crystallization pressures calculated from major element contents in mid-ocean ridge basalt (MORB) glasses and vapor-saturation pressures from melt inclusions and MORB glasses. Specifically, we use established major element barometers and pressures estimated from 192 fractional crystallization trends to calculate crystallization pressures from >9000 MORB glasses across the global range of mid-ocean ridge spreading rates. Additionally, we estimate vapor-saturation pressures from >400 MORB glasses from PETDB and >400 olivine-hosted melt inclusions compiled from five ridges with variable spreading rates. Both major element and vapor-saturation pressures increase and become more variable with decreasing …


Regional Sensitivities Of Seasonal Snowpack To Elevation, Aspect, And Vegetation Cover In Western North America, Nancy F. Glenn Aug 2017

Regional Sensitivities Of Seasonal Snowpack To Elevation, Aspect, And Vegetation Cover In Western North America, Nancy F. Glenn

Geosciences Faculty Publications and Presentations

In mountains with seasonal snow cover, the effects of climate change on snowpack will be constrained by landscape-vegetation interactions with the atmosphere. Airborne lidar surveys used to estimate snow depth, topography, and vegetation were coupled with reanalysis climate products to quantify these interactions and to highlight potential snowpack sensitivities to climate and vegetation change across the western U.S. at Rocky Mountain (RM), Northern Basin and Range (NBR), and Sierra Nevada (SNV) sites. In forest and shrub areas, elevation captured the greatest amount of variability in snow depth (16–79%) but aspect explained more variability (11–40%) in alpine areas. Aspect was most …


Trace Chemical Evaluation Of Cloud Seeding In The Payette Basin, James Mitchell Fisher Aug 2017

Trace Chemical Evaluation Of Cloud Seeding In The Payette Basin, James Mitchell Fisher

Boise State University Theses and Dissertations

Glaciogenic cloud seeding increases the fraction of super cooled liquid water precipitating from a given storm. Orographic clouds tend to be inefficient at higher cloud temperatures due to the lack of active natural ice nuclei. Adding artificial ice nuclei active at temperatures greater than -12oC (where most natural ice nuclei are inactive) may result in an increase in snow precipitation, especially in orographic clouds. Silver iodide (AgI) is typically the artificial nucleating agent for winter orographic cloud seeding. Recent estimates suggest the addition of AgI to orographic storm clouds enhance precipitation by 3 - 15%. However, the National …


If It Burns, Will It Flow? And About The Managers Who Would Like To Know: Predicting Post-Fire Debris Flows In The Rangeland Foothills Of Boise, Idaho & Investigating The Use Of Wildfire Science By Decision Makers At The Wildland Urban Interface, Katherine Gibble Aug 2017

If It Burns, Will It Flow? And About The Managers Who Would Like To Know: Predicting Post-Fire Debris Flows In The Rangeland Foothills Of Boise, Idaho & Investigating The Use Of Wildfire Science By Decision Makers At The Wildland Urban Interface, Katherine Gibble

Boise State University Theses and Dissertations

Wildfires increase erosion in mountainous landscapes. The most catastrophic form of post-fire erosion is the debris flow, viscous slurries of water and sediment capable of scouring and entraining larger sediment and rafting boulders. Post-fire debris flows are particularly hazardous when fire- and debris flow-prone landscapes intersect the Wildland Urban Interface (WUI). Homes built into the edge of the flammable WUI are at high risk of both wildfire and subsequent debris flows in mountainous landscapes of the western US, yet the WUI is expanding at an extraordinary rate. There are predictive models that inform citizens, land managers, and local governments of …


Geophysical Investigations Of Pyroclastic Density Current Processes And Deposit Properties At Mount St. Helens, Washington (Usa), Andrew Cleveland Gase Aug 2017

Geophysical Investigations Of Pyroclastic Density Current Processes And Deposit Properties At Mount St. Helens, Washington (Usa), Andrew Cleveland Gase

Boise State University Theses and Dissertations

Geophysical imaging has the potential to significantly improve investigations in pyroclastic deposits, either as a means of in situ property estimation or to provide geologic context where exposures do not exist. I perform two geophysical studies set in the deposits of the 1980 eruption at Mount St. Helens, Washington (USA); the aim is to investigate the physical properties and geology of pyroclastic deposits.

Joint petrophysical modeling reveals the dependence of seismic and electromagnetic velocities in pyroclastic deposits on two-phase porosity (vesicularity and inter- granular porosity) and water-saturation. Seismic first arrival travel-time tomography, multi-channel analysis of surface waves, and multi-offset GPR …


Exploring The Impact Of Climate And Land Cover Change On Regional Hydrology In A Snowmelt-Dominated Watershed: The Upper Boise River Basin, Idaho, Amy Steimke Aug 2017

Exploring The Impact Of Climate And Land Cover Change On Regional Hydrology In A Snowmelt-Dominated Watershed: The Upper Boise River Basin, Idaho, Amy Steimke

Boise State University Theses and Dissertations

Seasonally snow-dominated, mountainous watersheds supply water to many human populations globally. However, the timing and magnitude of water delivery from these watersheds has already and will continue to change as climate is altered. Associated changes in watershed vegetation cover further affect the runoff responses of watersheds, from altering evapotranspiration rates to changing surface energy fluxes, and there exists a need to incorporate land cover change in hydrologic modeling studies. However, few land cover projections exist at the scale needed for watershed studies, and current models may be unable to simulate key interactions that occur between land cover and hydrologic processes. …


Earthquake Segment Boundaries And Tsunamigenic Faults Of The Kodiak Segment, Alaska-Aleutian Subduction Zone, Marlon D. Ramos Aug 2017

Earthquake Segment Boundaries And Tsunamigenic Faults Of The Kodiak Segment, Alaska-Aleutian Subduction Zone, Marlon D. Ramos

Boise State University Theses and Dissertations

The most recent megathrust earthquake to impact the Alaska subduction zone was the M9.2 Great Alaska earthquake of 1964. This multi-segment rupture spanned over 700 km of the plate boundary and engendered both local and trans-Pacific tsunamis. The Kodiak Islands region served as the southwestern limit to rupture. The nature of past megathrust segmentation for the Alaska subduction zone has been largely hypothesized through paleoseismological methods and the Kodiak region in particular has not received a comprehensive geophysical characterization of its inferred segment boundaries.

I analyze multiple geophysical datasets (e.g. seismic reflection, earthquake, potential fields) to understand the spatiotemporal relationships …


Using Mountain Snowpack To Predict Summer Water Availability In Semiarid Mountain Watersheds, Rebecca Dawn Garst Aug 2017

Using Mountain Snowpack To Predict Summer Water Availability In Semiarid Mountain Watersheds, Rebecca Dawn Garst

Boise State University Theses and Dissertations

In the mountainous landscapes of the western United States, water resources are dominated by snowpack. As temperatures rise in spring and summer, the melting snow produces an increase in river flow levels. Reservoirs are used during this increase to retain surplus water, which is released to supplement growing season water supply once the peak flows decrease to below water demands. Once there is no longer surplus natural flow of water, the water accounting changes – referred to as the day of allocation (DOA), and water previously retained within the reservoir is used to supplement the lower flow levels. The amount …


Coupling Biophysical Processes And Water Rights To Simulate Spatially Distributed Water Use In An Intensively Managed Hydrologic System, Bangshuai Han, Shawn G. Benner, John P. Bolte, Kellie B. Vache, Alejandro N. Flores Jul 2017

Coupling Biophysical Processes And Water Rights To Simulate Spatially Distributed Water Use In An Intensively Managed Hydrologic System, Bangshuai Han, Shawn G. Benner, John P. Bolte, Kellie B. Vache, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

Humans have significantly altered the redistribution of water in intensively managed hydrologic systems, shifting the spatiotemporal patterns of surface water. Evaluating water availability requires integration of hydrologic processes and associated human influences. In this study, we summarize the development and evaluation of an extensible hydrologic model that explicitly integrates water rights to spatially distribute irrigation waters in a semi-arid agricultural region in the western US, using the Envision integrated modeling platform. The model captures both human and biophysical systems, particularly the diversion of water from the Boise River, which is the main water source that supports irrigated agriculture in this …


Volcanic Initiation Of The Eocene Heart Mountain Slide, Wyoming, Usa, Mark D. Schmitz Jul 2017

Volcanic Initiation Of The Eocene Heart Mountain Slide, Wyoming, Usa, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

The Eocene Heart Mountain slide of northwest Wyoming covers an area of as much as 5000 km2 and includes allochthonous Paleozoic carbonate and Eocene volcanic rocks with a run-out distance of as much as 85 km. Recent geochronologic data indicated that the emplacement of the slide event occurred at ∼48.9 Ma, using laser ablation inductively coupled plasmamass spectrometry (LA-ICPMS) extracted fromU-Pb zircon ages frombasal layer and injectite carbonate ultracataclasite (CUC). We now refine that age with U-Pb results from a lamprophyre diatreme that is temporally and spatially related to the CUC injectites. The ages for the lamprophyre zircons are …


Modeling The Isotopic Evolution Of Snowpack And Snowmelt: Testing A Spatially Distributed Parsimonious Approach, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon Jul 2017

Modeling The Isotopic Evolution Of Snowpack And Snowmelt: Testing A Spatially Distributed Parsimonious Approach, Pertti Ala-Aho, Doerthe Tetzlaff, James P. Mcnamara, Hjalmar Laudon

Geosciences Faculty Publications and Presentations

Use of stable water isotopes has become increasingly popular in quantifying water flow paths and travel times in hydrological systems using tracer-aided modeling. In snow-influenced catchments, snowmelt produces a traceable isotopic signal, which differs from original snowfall isotopic composition because of isotopic fractionation in the snowpack. These fractionation processes in snow are relatively well understood, but representing their spatiotemporal variability in tracer-aided studies remains a challenge. We present a novel, parsimonious modeling method to account for the snowpack isotope fractionation and estimate isotope ratios in snowmelt water in a fully spatially distributed manner. Our model introduces two calibration parameters that …


Aerodynamic Roughness Length Estimation With Lidar And Imaging Spectroscopy In A Shrub-Dominated Dryland, Aihua Li, Wenguang Zhao, Jessica J. Mitchell, Nancy F. Glenn, Matthew J. Germino, Joel B. Sankey, Richard G. Allen Jun 2017

Aerodynamic Roughness Length Estimation With Lidar And Imaging Spectroscopy In A Shrub-Dominated Dryland, Aihua Li, Wenguang Zhao, Jessica J. Mitchell, Nancy F. Glenn, Matthew J. Germino, Joel B. Sankey, Richard G. Allen

Geosciences Faculty Publications and Presentations

The aerodynamic roughness length (Z0m) serves an important role in the flux exchange between the land surface and atmosphere. In this study, airborne lidar (ALS), terrestrial lidar (TLS), and imaging spectroscopy data were integrated to develop and test two approaches to estimate Z0m over a shrub dominated dryland study area in south-central Idaho, USA. Sensitivity of the two parameterization methods to estimate Z0m was analyzed. The comparison of eddy covariance-derived Z0m and remote sensing-derived Z0m showed that the accuracy of the estimated Z0m heavily depends on the estimation model and the representation of …


Identifying Irrigated Areas In The Snake River Plain, Idaho: Evaluating Performance Across Composting Algorithms, Spectral Indices, And Sensors, Eric W. Chance, Kelly M. Cobourn, Valerie A. Thomas, Blaine C. Dawson, Alejandro N. Flores Jun 2017

Identifying Irrigated Areas In The Snake River Plain, Idaho: Evaluating Performance Across Composting Algorithms, Spectral Indices, And Sensors, Eric W. Chance, Kelly M. Cobourn, Valerie A. Thomas, Blaine C. Dawson, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

There are pressing concerns about the interplay between agricultural productivity, water demand, and water availability in semi-arid to arid regions of the world. Currently, irrigated agriculture is the dominant water user in these regions and is estimated to consume approximately 80% of the world’s diverted freshwater resources. We develop an improved irrigated land-use mapping algorithm that uses the seasonal maximum value of a spectral index to distinguish between irrigated and non-irrigated parcels in Idaho’s Snake River Plain. We compare this approach to two alternative algorithms that differentiate between irrigated and non-irrigated parcels using spectral index values at a single date …


Bridging The Gap Between The Foreland And Hinterland Ii: Geochronology And Tectonic Setting Of Ordovician Magmatism And Basin Formation On The Laurentian Margin Of New England And Newfoundland, Francis A. Macdonald, Paul M. Karabinos, James L. Crowley, Eben B. Hodgin, Peter W. Crockford, John W. Delano May 2017

Bridging The Gap Between The Foreland And Hinterland Ii: Geochronology And Tectonic Setting Of Ordovician Magmatism And Basin Formation On The Laurentian Margin Of New England And Newfoundland, Francis A. Macdonald, Paul M. Karabinos, James L. Crowley, Eben B. Hodgin, Peter W. Crockford, John W. Delano

Geosciences Faculty Publications and Presentations

Ordovician strata of the Mohawk Valley and Taconic allochthon of New York and the Humber margin of Newfoundland record multiple magmatic and basin-forming episodes associated with the Taconic orogeny. Here we present new U-Pb zircon geochronology and whole rock geochemistry and neodymium isotopes from Early Paleozoic volcanic ashes and siliciclastic units on the northern Appalachian margin of Laurentia. Volcanic ashes in the Table Point Formation of Newfoundland and the Indian River Formation of the Taconic allochthon in New York yield dates between 466.16 ± 0.12 and 464.20 ± 0.13 Ma. Red, bioturbated slate of the Indian River Formation record a …


Bridging The Gap Between The Foreland And Hinterland I: Geochronology And Plate Tectonic Geometry Of Ordovician Magmatism And Terrane Accretion On The Laurentian Margin Of New England, Paul M. Karabinos, Francis A. Macdonald, James L. Crowley May 2017

Bridging The Gap Between The Foreland And Hinterland I: Geochronology And Plate Tectonic Geometry Of Ordovician Magmatism And Terrane Accretion On The Laurentian Margin Of New England, Paul M. Karabinos, Francis A. Macdonald, James L. Crowley

Geosciences Faculty Publications and Presentations

U-Pb dates on magmatic and detrital zircon from samples in the hinterland of the Taconic orogen place new constraints on the timing and plate tectonic geometry of terrane accretion and magmatic arc activity. The Moretown terrane, a Gondwanan-derived exotic block, extends from the Rowe Schist-Moretown Formation contact in the west to the Bronson Hill arc in the east. Arc-related plutonic and volcanic rocks formed above an east-dipping subduction zone under the western leading edge of the Moretown terrane from approximately 500 to 475 Ma, until collision with hyperextended distal fragments of Laurentia, represented by the Rowe Schist, at 475 Ma. …


Investigations On The Mesozoic Geologic And Tectonic History Of The Jackson Mountains, Northwest Nevada, Thomas Anthony Colby May 2017

Investigations On The Mesozoic Geologic And Tectonic History Of The Jackson Mountains, Northwest Nevada, Thomas Anthony Colby

Boise State University Theses and Dissertations

New geologic mapping, high-precision U-Pb zircon geochronology, and isotope geochemistry provide insight into the early Mesozoic paleogeography and magmatic, stratigraphic, and structural evolution of the Jackson Mountains in the Black Rock Desert region of northwest Nevada. The magmatic history of the Jackson Mountains records Late Triassic to Early Jurassic (~215-195 Ma) marine deposition of the Boulder Creek Beds adjacent to the arc followed by the Early Jurassic (~193-189 Ma) eruption and emplacement of the Happy Creek Igneous Complex and associated plutons of the Early Mesozoic Intrusive Suite. Pb, Sr, and Nd isotopic data from Early Jurassic intrusive rocks of the …


Geochronology Of The Tectonic, Stratigraphic, And Magmatic Evolution Of Neoproterozoic To Early Paleozoic, North American Cordillera And Cryogenian Glaciation, Vincent H. Isakson May 2017

Geochronology Of The Tectonic, Stratigraphic, And Magmatic Evolution Of Neoproterozoic To Early Paleozoic, North American Cordillera And Cryogenian Glaciation, Vincent H. Isakson

Boise State University Theses and Dissertations

Neoproterozoic sedimentary successions contain evidence for some of the most extreme climate fluctuations, breakup of the paleo-supercontinent Rodina, multiple low-latitude global glaciations, and the resultant evolution and radiation of complex life. The stratigraphic record of these events are found on all major continents and have been associated with, in part, global ‘Snowball Earth’ events. However, the understanding and integration of these, and related phenomenon, are limited by disparate and imprecise age constraints that prohibit clear correlation between locations.

This research focused on high-precision geochronology within an integrated framework of sedimentology, stratigraphy, and geochemistry to resolve the timing and duration of …


Inference Of Soil Hydrologic Parameters From Electronic Soil Moisture Records, David G. Chandler, Mark S. Seyfried, James P. Mcnamara, Kyotaek Hwang Apr 2017

Inference Of Soil Hydrologic Parameters From Electronic Soil Moisture Records, David G. Chandler, Mark S. Seyfried, James P. Mcnamara, Kyotaek Hwang

Geosciences Faculty Publications and Presentations

Soil moisture is an important control on hydrologic function, as it governs vertical fluxes from and to the atmosphere, groundwater recharge, and lateral fluxes through the soil. Historically, the traditional model parameters of saturation, field capacity, and permanent wilting point have been determined by laboratory methods. This approach is challenged by issues of scale, boundary conditions, and soil disturbance. We develop and compare four methods to determine values of field saturation, field capacity, plant extraction limit (PEL), and initiation of plant water stress from long term in-situ monitoring records of TDR-measured volumetric water content (Θ). The monitoring sites represent a …


Developing A Tree-Ring Chronology For Reconstructing Past Climate Conditions: Coral Pink Sand Dunes, Ut, Amy L. Cutter Apr 2017

Developing A Tree-Ring Chronology For Reconstructing Past Climate Conditions: Coral Pink Sand Dunes, Ut, Amy L. Cutter

McNair Scholars Research Journal

The Coral Pink Sand Dunes (CPSD) is one of the largest active dune fields in the Grand Staircase of the Colorado Plateau. A disjunct stand of ponderosa pine (Pinus ponderosa) seemingly thrives within the dune field. The presence of a multiple-aged stand suggests the site has experienced varied climatic conditions since becoming established. Other geomorphic systems in the region (e.g., arroyos) indicate sensitivity to small climate fluctuations; perhaps the dunes are similarly sensitive, leading to the question—could the trees be used to reconstruct past climate, and could that reconstruction be used to model dune activity with climate variability. The climate-growth …


Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box Mar 2017

Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box

CGISS Publications and Presentations

The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past …