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Articles 361 - 390 of 667
Full-Text Articles in Earth Sciences
Evidence Of Erosional Self-Channelization Of Pyroclastic Density Currents Revealed By Ground-Penetrating Radar Imaging At Mount St. Helens, Washington (Usa), Andrew C. Gase, Brittany D. Brand, John H. Bradford
Evidence Of Erosional Self-Channelization Of Pyroclastic Density Currents Revealed By Ground-Penetrating Radar Imaging At Mount St. Helens, Washington (Usa), Andrew C. Gase, Brittany D. Brand, John H. Bradford
Geosciences Faculty Publications and Presentations
The causes and effects of erosion are among the least understood aspects of pyroclastic density current (PDC) dynamics. Evidence is especially limited for erosional self-channelization, a process whereby PDCs erode a channel that confines the body of the eroding flow or subsequent flows. We use ground-penetrating radar imaging to trace a large PDC scour and fill from outcrop to its point of inception and discover a second, larger PDC scour and fill. The scours are among the largest PDC erosional features on record, at >200 m wide and at least 500 m long; estimated eroded volumes are on the order …
Probabilistic Inversion With Graph Cuts: Application To The Boise Hydrogeophysical Research Site, Guillaume Pirot, Niklas Linde, Grégoire Mariethoz, John H. Bradford
Probabilistic Inversion With Graph Cuts: Application To The Boise Hydrogeophysical Research Site, Guillaume Pirot, Niklas Linde, Grégoire Mariethoz, John H. Bradford
CGISS Publications and Presentations
Inversion methods that build on multiple-point statistics tools offer the possibility to obtain model realizations that are not only in agreement with field data, but also with conceptual geological models that are represented by training images. A recent inversion approach based on patch-based geostatistical resimulation using graph cuts outperforms state-of-the-art multiple-point statistics methods when applied to synthetic inversion examples featuring continuous and discontinuous property fields. Applications of multiple-point statistics tools to field data are challenging due to inevitable discrepancies between actual subsurface structure and the assumptions made in deriving the training image. We introduce several amendments to the original graph …
Household Preparedness Motivation In Lahar Hazard Zones: Assessing The Adoption Of Preparedness Behaviors Among Laypeople And Response Professionals In Communities Downstream From Mount Baker And Glacier Peak (Usa) Volcanoes, Kimberley A. Corwin, Brittany D. Brand, Monica L. Hubbard, David M. Johnston
Household Preparedness Motivation In Lahar Hazard Zones: Assessing The Adoption Of Preparedness Behaviors Among Laypeople And Response Professionals In Communities Downstream From Mount Baker And Glacier Peak (Usa) Volcanoes, Kimberley A. Corwin, Brittany D. Brand, Monica L. Hubbard, David M. Johnston
Geosciences Faculty Publications and Presentations
As the number of people living at risk from volcanic hazards in the U.S. Pacific Northwest grows, more detailed studies of household preparedness in at-risk communities are needed to develop effective mitigation, response, and recovery plans. This study examines two aspects of preparedness behavior motivation in the Skagit Valley (WA), which is at risk from Mount Baker and Glacier Peak lahars. First, we examine the influence of perceived response-efficacy, protective response costs, self-efficacy, and ascription of responsibility on preparedness. Results indicate few respondents believe high perceived protective response costs, low perceived response-efficacy, or low perceived protection responsibility prevent them from …
Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. Mcnamara
Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. Mcnamara
Geosciences Faculty Publications and Presentations
The phase of precipitation when it reaches the ground is a first-order driver of hydrologic processes in a watershed. The presence of snow, rain, or mixed-phase precipitation affects the initial and boundary conditions that drive hydrological models. Despite their foundational importance to terrestrial hydrology, typical phase partitioning methods (PPMs) specify the phase based on near-surface air temperature only. Our review conveys the diversity of tools available for PPMs in hydrological modeling and the advancements needed to improve predictions in complex terrain with large spatiotemporal variations in precipitation phase. Initially, we review the processes and physics that control precipitation phase as …
Biotic Changes Around The Radioisotopically Constrained Carboniferous-Permian Boundary In The Boskovice Basin (Czech Republic), Stanislav Oplustil, Jakub Jirásek, Mark Schmitz, Dalibor Matýsek
Biotic Changes Around The Radioisotopically Constrained Carboniferous-Permian Boundary In The Boskovice Basin (Czech Republic), Stanislav Oplustil, Jakub Jirásek, Mark Schmitz, Dalibor Matýsek
Geosciences Faculty Publications and Presentations
Presented is an analysis of vegetation patterns across the Carboniferous-Permian boundary in continental setting constrained for the first time in Europe and North America by high-precision U-Pb radioisotopic dating. The analysis is performed on the fossil record of the Boskovice Basin (Czech Republic), a Late Palaeozoic half-graben having ~ 5 km of cumulative thickness. It is dominantly a red bed succession containing numerous grey, mostly lacustrine horizons bearing fairly rich fossil floras and faunas of Late Pennsylvanian to Cisuralian age. U-Pb geochronology on single zircon crystals separated from a volcanic tuff near the top of the Rosice-Oslavany Formation, in the …
Laser Ultrasound Observations Of Mechanical Property Variations In Ice Cores, Thomas Dylan Mikesell, Kasper Van Wijk, Larry Thomas Otheim, Hans-Peter Marshall, Andrei Kurbatov
Laser Ultrasound Observations Of Mechanical Property Variations In Ice Cores, Thomas Dylan Mikesell, Kasper Van Wijk, Larry Thomas Otheim, Hans-Peter Marshall, Andrei Kurbatov
Geosciences Faculty Publications and Presentations
The study of climate records in ice cores requires an accurate determination of annual layering within the cores in order to establish a depth-age relationship. Existing tools to delineate these annual layers are based on observations of changes in optical, chemical, and electromagnetic properties. In practice, no single technique captures every layer in all circumstances. Therefore, the best estimates of annual layering are produced by analyzing a combination of measurable ice properties. We present a novel and complimentary elastic wave remote sensing method based on laser ultrasonics. This method is used to measure variations in ultrasonic wave arrival times and …
Geothermal Play Fairway Analysis Of The Snake River Plain: Phase 2, Lee M. Liberty
Geothermal Play Fairway Analysis Of The Snake River Plain: Phase 2, Lee M. Liberty
CGISS Publications and Presentations
Play Fairway Analysis (PFA) is a methodology adapted from the petroleum industry that integrates data at the regional or basin scale to define favorable plays for exploration in a systematic fashion. Phase 2 of our Play Fairway Analysis of the Western Snake River Plain (WSRP) province in southern Idaho had three primary goals: first, to fill data gaps in critical areas in order to better define potential prospects, second, to integrate these data into new thermal and structural models, and finally, to infer the location of potential resources and drilling targets that could be validated during Phase 3. Prospects in …
Impact Of Spatial Averaging On Radar Reflectivity At Internal Snowpack Layer Boundaries, N. Rutter, H.P. Marshall, K. Tape, R. Essery, J. King
Impact Of Spatial Averaging On Radar Reflectivity At Internal Snowpack Layer Boundaries, N. Rutter, H.P. Marshall, K. Tape, R. Essery, J. King
CGISS Publications and Presentations
Microwave radar amplitude within a snowpack can be strongly influenced by spatial variability of internal layer boundaries. We quantify the impact of spatial averaging of snow stratigraphy and physical snowpack properties on surface scattering from near-nadir frequency-modulated continuous- wave radar at 12–18 GHz. Relative permittivity, density, grain size and stratigraphic boundaries were measured in-situ at high resolution along the length of a 9 m snow trench. An optimal range of horizontal averaging (4–6 m) was identified to attribute variations in surface scattering at layer boundaries to dielectric contrasts estimated from centimetre-scale measurements of snowpack stratigraphy and bulk layer properties. Single …
Using Near-Infrared Photography To Better Study Snow Microstructure And Its Variability Over Time And Space, Jesse Raymond Dean
Using Near-Infrared Photography To Better Study Snow Microstructure And Its Variability Over Time And Space, Jesse Raymond Dean
Boise State University Theses and Dissertations
The methods typically used to study snow stratigraphy, microstructure, and variability are expensive, cumbersome, and often highly subjective. Near-infrared (NIR) photography is a low-cost, portable tool to rapidly collect high-resolution, objective measurements of snow microstructure and variability. To expand its application, an active-source NIR flash was introduced to the traditionally passive-source method. NIR imagery was collected alongside proven snowpit methods such as manual observation, Snow Fork wetness, and Snow Micro-Penetrometer hardness profiles. NIR photography was also deployed in five pits along a 10.6 km transect in Grand Mesa, CO, to track stratigraphy variations in space. The NIR flash was found …
Continuous Snow Water Equivalent Measurements With Ultra-Wideband Radar: Towards A New Generation Of Real-Time Automated Snow Sensor Arrays, Mark Edward Robertson
Continuous Snow Water Equivalent Measurements With Ultra-Wideband Radar: Towards A New Generation Of Real-Time Automated Snow Sensor Arrays, Mark Edward Robertson
Boise State University Theses and Dissertations
Snow accounts for the majority of precipitation in many areas of the Western United States, and accurate measurements of the amount of water contained in the snowpack, known as snow water equivalent (SWE), are therefore important for water resource managers. The National Resources Conservation Service Snow Telemetry (SNOTEL) sites are the current standard remote measurement of SWE, with approximately 800 sites across the Western United States. Measurements at these sites are made by snow pillows, which weigh the overburden pressure of a snowpack, and are relatively expensive to install and maintain. Spring runoff is modeled using a 30-year average of …
Controls On The Presence, Concentration, Storage, And Variability Of Soil Inorganic Carbon In A Semi-Arid Watershed, Christopher Allen Stanbery
Controls On The Presence, Concentration, Storage, And Variability Of Soil Inorganic Carbon In A Semi-Arid Watershed, Christopher Allen Stanbery
Boise State University Theses and Dissertations
Soil inorganic carbon (SIC) constitutes approximately 40% of terrestrial soil carbon and is an integral part of the global carbon cycle; however, the controls on the storage and flux of inorganic carbon are poorly understood. Soil forming factors controlling SIC storage and flux include climate, organisms, relief, parent material, and time (Jenny, 1941). Rainfall is a primary factor controlling SIC accumulation in arid and semi-arid regions, but the hierarchy of controls on SIC development is complex. The Reynolds Creek Experimental Watershed in southwestern Idaho is an ideal location to study factors influencing SIC, as the carbon pool transitions from predominately …
Using Infrasound Waves To Monitor Tropospheric Weather And Crater Morphology Changes, Hugo David Ortiz
Using Infrasound Waves To Monitor Tropospheric Weather And Crater Morphology Changes, Hugo David Ortiz
Boise State University Theses and Dissertations
Infrasound waves generated during volcanic eruptions and recorded near the vent are used to study both changing atmospheric conditions and volcano eruption source characteristics. Infrasound data were recorded for a 32 month period at Volcán Tungurahua (Ecuador) by a five-station network located within 6.5 km from the vent. Infrasound detections made through cross-network correlation indicate cyclic eruptive behavior, which is corroborated by reports from the Ecuadorian monitoring agency. Cross-network correlation lag times are used to compute _10 m resolution infrasound source positions, which take into account NOAA models of local wind and temperature. Variable infrasound-derived source locations suggests source migration …
The Hydrogeologic Information In Cross-Borehole Complex Conductivity Data From An Unconsolidated Conglomeratic Sedimentary Aquifer, Andrew Binley, John Keery, Lee Slater, Warren Barrash, Mike Cardiff
The Hydrogeologic Information In Cross-Borehole Complex Conductivity Data From An Unconsolidated Conglomeratic Sedimentary Aquifer, Andrew Binley, John Keery, Lee Slater, Warren Barrash, Mike Cardiff
Geosciences Faculty Publications and Presentations
Accurate estimation of the hydrological properties of near-surface aquifers is important because these properties strongly influence groundwater flow and solute transport. Laboratory-based investigations have indicated that induced polarization (IP) properties of porous media may be linked, through either semi-empirical or fully mechanistic models, to hydrological properties including hydraulic conductivity. Therefore, there is a need for field assessments of the value of IP measurements in providing insights into the hydrological properties of aquifers. A cross-borehole IP survey was carried out at the Boise Hydrogeophysical Research Site (BHRS), an unconsolidated fluvial aquifer that has previously been well-studied with a variety of geophysical …
Middle Permian U-Pb Zircon Ages Of The "Glacial" Deposits Of The Atkan Formation, Ayan-Yuryakh Anticlinorium, Magadan Province, Ne Russia: Their Significance For Global Climatic Interpretations, V. I. Davydov, A. S. Biakov, J. L. Isbell, J. Crowley, M. D. Schmitz, I. L. Vedernikov
Middle Permian U-Pb Zircon Ages Of The "Glacial" Deposits Of The Atkan Formation, Ayan-Yuryakh Anticlinorium, Magadan Province, Ne Russia: Their Significance For Global Climatic Interpretations, V. I. Davydov, A. S. Biakov, J. L. Isbell, J. Crowley, M. D. Schmitz, I. L. Vedernikov
Geosciences Faculty Publications and Presentations
The Atkan Formation in the Ayan-Yuryakh anticlinorium, Magadan province, northeastern Russia, is of great interest because of the occurrence of deposits of apparent “dropstones” and “ice rafted debris” that have been previously interpreted as glacial. Two high-precision U-Pb zircon ages, one for an intercalated volcanic tuff (262.5 ± 0.2 Ma) and the other for a boulder clast (269.8 ± 0.1 Ma) within a diamictite of the Atkan Formation, constrain the age of the Atkan Formation as Guadalupian (middle Permian). Sedimentologic study of the Atkan Formation casts doubt on the glacial nature of the diamictites. Deposition of rocks of the Atkan …
Isolating Retrograde And Prograde Rayleigh-Wave Modes Using A Polarity Mute, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell, Paul Michaels
Isolating Retrograde And Prograde Rayleigh-Wave Modes Using A Polarity Mute, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell, Paul Michaels
Geosciences Faculty Publications and Presentations
Estimates of S-wave velocity with depth from Rayleigh-wave dispersion data are limited by the accuracy of fundamental and/or higher mode signal identification. In many scenarios, the fundamental mode propagates in retrograde motion, whereas higher modes propagate in prograde motion. This difference in particle motion (or polarity) can be used by joint analysis of vertical and horizontal inline recordings. We have developed a novel method that isolates modes by separating prograde and retrograde motions; we call this a polarity mute. Applying this polarity mute prior to traditional multichannel analysis of surface wave (MASW) analysis improves phase velocity estimation for fundamental and …
Biotic Paleothermometry Constrains On Arctic Plates Reconstructions: Carboniferous And Permian (Zhokhov Island, De-Longa Group Islands, New Siberian Archipelago), Vladimir I. Davydov
Biotic Paleothermometry Constrains On Arctic Plates Reconstructions: Carboniferous And Permian (Zhokhov Island, De-Longa Group Islands, New Siberian Archipelago), Vladimir I. Davydov
Geosciences Faculty Publications and Presentations
A warm-water fauna and flora from a Carboniferous limestone xenolith that was captured during penetration of deep intraplate Cenozoic basalts through a Paleozoic carbonate platform have been found on Zhokhov Island, New Siberian Archipelago (NSA). This limestone xenolith contains a very high taxonomic diversity of Moscovian (Middle Pennsylvanian) tropical foraminifera and calcareous algae. As this warm-water biota never occurs north of the forbiddance line, i.e., 30–35°N/S, this fauna and algal flora constrain the paleogeography and interpretation of the paleotectonics in the region. Thus, the location of the most of the New Siberian Archipelago islands at that time must have been …
Linking In Situ Lai And Fine Resolution Remote Sensing Data To Map Reference Lai Over Cropland And Grassland Using Geostatistical Regression Method, Yaqian He, Yanchen Bo, Leilei Chai, Xiaolong Liu, Aihua Li
Linking In Situ Lai And Fine Resolution Remote Sensing Data To Map Reference Lai Over Cropland And Grassland Using Geostatistical Regression Method, Yaqian He, Yanchen Bo, Leilei Chai, Xiaolong Liu, Aihua Li
Geosciences Faculty Publications and Presentations
Leaf Area Index (LAI) is an important parameter of vegetation structure. A number of moderate resolution LAI products have been produced in urgent need of large scale vegetation monitoring. High resolution LAI reference maps are necessary to validate these LAI products. This study used a geostatistical regression (GR) method to estimate LAI reference maps by linking in situ LAI and Landsat TM/ETM+ and SPOT-HRV data over two cropland and two grassland sites. To explore the discrepancies of employing different vegetation indices (VIs) on estimating LAI reference maps, this study established the GR models for different VIs, including difference vegetation index …
Geologic, Geochemical, And Geophysical Characterization Of The Gold Deposits Of The Horseshoe Bend Mining District, Idaho: Building A Four Dimensional Model For Ore Exploration, Joshua Ekhoff
Boise State University Theses and Dissertations
The Eocene aged Trans-Challis Fault System of central Idaho provides the tectonic and magmatic framework for a series of Au-Ag and Cu-Mo ore deposits. From its northernmost extension near Butte, Montana to its southwestern terminus in the Boise Basin of south-central Idaho the Trans-Challis Fault System is associated with some of the richest precious metal deposits found in Idaho. However, the southernmost tip of the Trans-Challis Fault System, composed of the Horseshoe Bend and Pearl mining districts, remains understudied, receiving little economic or academic attention. As a result, how the Pearl to Horseshoe Bend mining districts fit within the established …
Pre-Eruptive Timescales And Processes Of Large Shallow Magma Systems Revealed By Compositional Variability In Silicic Ignimbrites, Amanda C. Laib
Pre-Eruptive Timescales And Processes Of Large Shallow Magma Systems Revealed By Compositional Variability In Silicic Ignimbrites, Amanda C. Laib
Boise State University Theses and Dissertations
Intracontinental magmas are stored at shallow crustal depths and commonly produce compositionally variable deposits when erupted. A core objective of igneous petrology is to understand the processes and pathways by which these magmas are generated and differentiated. Despite decades of research, debate persists regarding the comparative effects of processes like assimilation, fractional crystallization, and magma mixing in the production of compositional zonation. There are two end member hypotheses of how compositional variability develops in pre-eruptive magma bodies; one proposes long-term storage and crystal fractionation of a mafic or intermediate parent magma, while the other proposes a more transient system resulting …
Feedbacks Among Climate, Soils, Vegetation, And Erosion Drive Valley Asymmetry Development In The Mountains Of Central Idaho, Michael John Poulos
Feedbacks Among Climate, Soils, Vegetation, And Erosion Drive Valley Asymmetry Development In The Mountains Of Central Idaho, Michael John Poulos
Boise State University Theses and Dissertations
Aspect has long been recognized as a significant source of landscape variability, which is induced by the orientation of land surfaces relative to solar incidence. Insolation differences on opposing aspects (e.g., north and south-facing slopes) act as localized climatic perturbations, altering surface energy balances and temperatures. Over shorter timescales, aspect-induced changes to the energy balance alter snow pack dynamics, soil water input rates and seasonality, and plant available water and water stress. Over longer timescales, aspect-induced insolation variability affects bedrock weathering rates and depths, soil and regolith development, vegetation type and density, erosion rates and processes, and ultimately hillslope and …
Living In Lahar Zones: Assessing Hazard Exposure, Risk Perception, And Preparedness Behaviors In Communities Within The Mount Baker And Glacier Peak Volcanic Hazard Zones, Kimberley Anne Corwin
Living In Lahar Zones: Assessing Hazard Exposure, Risk Perception, And Preparedness Behaviors In Communities Within The Mount Baker And Glacier Peak Volcanic Hazard Zones, Kimberley Anne Corwin
Boise State University Theses and Dissertations
As the number of people living at risk from volcanic hazards in the U.S. Pacific Northwest grows, more detailed studies of community hazard exposure, risk perception, and preparedness levels become critical to developing effective mitigation, response, and recovery plans. This thesis uses risk mapping and a knowledge, risk perception, and preparedness survey to examine the risk that lahars from Mount Baker and Glacier Peak volcanoes pose to nearby communities in the Skagit Valley (WA). The risk map component of this research identifies spatial variations in lahar risk and estimates potential losses associated with a maximum envisioned lahar. The survey component …
Lava Lake Eruptive Processes Quantified With Infrasound And Video At Mount Erebus, Antarctica, Alexander Miller
Lava Lake Eruptive Processes Quantified With Infrasound And Video At Mount Erebus, Antarctica, Alexander Miller
Boise State University Theses and Dissertations
A natural laboratory exists at Mount Erebus where strombolian activity from the lava lake is directly observed from the crater rim. Lava lake eruptions occur when pressurized bubble slugs distend the lake surface before bursting within a few tenths of a second. The unique setting presents an ideal site to quantify bubble growth through infrasound and video analysis. Two infrasound sensors and one video camera recorded eruptions ~330 m from the lava lake in 2006. Infrasound waveforms exhibit a high-amplitude bipolar pulse followed by a coda consisting of about five decaying oscillations. Video records are quantified by tracking the expanding …
Protracted Thrusting Followed By Late Rapid Cooling Of The Greater Himalayan Sequence, Annapurna Himalaya, Central Nepal: Insights From Titanite Petrochronology, Jesse Bennett Walters
Protracted Thrusting Followed By Late Rapid Cooling Of The Greater Himalayan Sequence, Annapurna Himalaya, Central Nepal: Insights From Titanite Petrochronology, Jesse Bennett Walters
Boise State University Theses and Dissertations
Temperature-time (T-t) paths derived from coupled Zr-in-titanite thermometry and U-Pb geochronology are useful for examining middle-crustal tectonic processes. T-t data collected from the titanite-bearing calcsilicates of the upper Greater Himalayan Sequence (GHS) along the Marsyandi River, Annapurna Himalaya, illustrate a significantly different metamorphic history than previously recorded in central Nepal. Combined with traditional thermobarometry, textural relationships, and field mapping, titanite T-t data reveal a protracted history of mid-crustal tectonics. Peak Zr-in-titanite temperatures are 750-850 °C at 10-14 kbar. T-t paths are divided into two groups, which are separated by the Chame Shear Zone (CSZ). Group I (upper) rocks show cooling …
Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto
Monitoring Southwest Greenland’S Ice Sheet Melt With Ambient Seismic Noise, Aurélien Mordret, T. Dylan Mikesell, Christopher Harig, Bradley P. Lipovsky, Germán A. Prieto
CGISS Publications and Presentations
The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. …
Using Stable Isotope Hydrology To Partition Evapotranspiration In The Sagebrush Steppe, Kellie Jo Rey
Using Stable Isotope Hydrology To Partition Evapotranspiration In The Sagebrush Steppe, Kellie Jo Rey
Boise State University Theses and Dissertations
Evapotranspiration (ET) is a major part of ecosystem water loss. This thesis aims to develop methods that partition soil water loss into evaporation (E) and transpiration (T). Water balance methods may improve with relative contributions of evaporation (E) and transpiration (T). Isotopic fractionation distinguishes soil water loss due to evaporation from that of plant uptake. This provides a means to assess E and T in retrospect rather than only measuring ET fluxes. To measure the isotopic composition of soil water, we used a liquid-vapor equilibration method following Wassenaar (2008). Experimental trials of different soil amounts and equilibration times were performed …
Statistical Modeling To Predict N2O Production Within The Hyporheic Zone By Coupling Denitrifying Microbial Community Abundance To Geochemical And Hydrological Parameters, Tiffany Brooke Farrell
Statistical Modeling To Predict N2O Production Within The Hyporheic Zone By Coupling Denitrifying Microbial Community Abundance To Geochemical And Hydrological Parameters, Tiffany Brooke Farrell
Boise State University Theses and Dissertations
The hyporheic zone (HZ) of streams can be a significant source of nitrous oxide (N2O). However, the biogeochemical processes controlling N2O emissions remain poorly constrained due to difficulties in obtaining high-resolution chemical, physical, and biological data from streams. We performed a large-scale flume experiment to unravel the complexities of a natural system by constraining streambed morphology, flow rate, organic carbon loading, grain size distribution, and exogenous nitrate loading while enabling regular monitoring of dissolved oxygen, pH, alkalinity, and concentrations of NO3-, NO2-, NH4+, and N2O …
Riparian Zone Evapotranspiration Using Streamflow Diel Signals, Ethan Thomas Geisler
Riparian Zone Evapotranspiration Using Streamflow Diel Signals, Ethan Thomas Geisler
Boise State University Theses and Dissertations
Riparian zones are crucial regions of semi-arid and arid watersheds. In the summer, riparian zones provide an important habitat for the watershed since they have sufficient water supply throughout the year. However, little is known about the impact of riparian zone evapotranspiration (ET) at a watershed scale. The use of streamflow diel signals can provide a more thorough understanding of riparian zone processes, particularly evapotranspiration. The streamflow diel signals were analyzed for Dry Creek Experimental Watershed (DCEW), for the summer of 2014, to determine riparian evapotranspiration. The riparian zone evapotranspiration was compared to a spatially distributed evapotranspiration model to determine …
Isotopic Evidence For Lateral Flow And Diffusive Transport, But Not Sublimation, In A Sloped Seasonal Snowpack, Idaho, Usa, Samantha L. Evans, Alejandro N. Flores, Achim Heilig, Matthew J. Kohn, Hans-Peter Marshall, James P. Mcnamara
Isotopic Evidence For Lateral Flow And Diffusive Transport, But Not Sublimation, In A Sloped Seasonal Snowpack, Idaho, Usa, Samantha L. Evans, Alejandro N. Flores, Achim Heilig, Matthew J. Kohn, Hans-Peter Marshall, James P. Mcnamara
Geosciences Faculty Publications and Presentations
Oxygen and hydrogen isotopes in snow were measured in weekly profiles during the growth and decline of a sloped subalpine snowpack, southern Idaho, 2011–2012. Isotopic steps (10‰, δ18O; 80‰, δD) were preserved relative to physical markers throughout the season, albeit with some diffusive smoothing. Melting stripped off upper layers without shifting isotopes within the snowpack. Meltwater is in isotopic equilibrium with snow at the top but not with snow at each respective collection height. Transport of meltwater occurred primarily along pipes and lateral flow paths allowing the snowpack to melt initially in reverse stratigraphic order. Isotope diffusivities are …
Aquifer Arsenic Cycling Induced By Seasonal Hydrologic Changes Within The Yangtze River Basin, Michael V. Schaefer, Samantha C. Ying, Shawn G. Benner, Yanhua Duan, Yanxin Wang, Scott Fendorf
Aquifer Arsenic Cycling Induced By Seasonal Hydrologic Changes Within The Yangtze River Basin, Michael V. Schaefer, Samantha C. Ying, Shawn G. Benner, Yanhua Duan, Yanxin Wang, Scott Fendorf
Geosciences Faculty Publications and Presentations
Consumption of groundwater containing >10 μg L−1 arsenic (As) adversely impacts more than 100 million people worldwide. Multiyear trends in aquifer As concentrations have been documented, but strong seasonal variations are not commonly observed. Here we report dramatic seasonal changes in As concentrations and aquifer chemistry within the Jianghan Plain of the Yangtze River, China. At some wells, concentrations fluctuate by more than an order of magnitude within a single year (100−1200 μg L−1). Groundwater extraction and sustained water levels of surface channels during the dry season induces a strong downward hydraulic gradient, seasonally supplying …
Zircon U-Pb Ages And Hf Isotopes Of The Askot Klippe, Kumaun, Northwest India: Implications For Paleoproterozoic Tectonics, Basin Evolution And Associated Metallogeny Of The Northern Indian Cratonic Margin, Subhadip Mandal, Delores M. Robinson, Matthew J. Kohn, Subodha Khanal, Oindrila Das, Sukhanjan Bose
Zircon U-Pb Ages And Hf Isotopes Of The Askot Klippe, Kumaun, Northwest India: Implications For Paleoproterozoic Tectonics, Basin Evolution And Associated Metallogeny Of The Northern Indian Cratonic Margin, Subhadip Mandal, Delores M. Robinson, Matthew J. Kohn, Subodha Khanal, Oindrila Das, Sukhanjan Bose
Geosciences Faculty Publications and Presentations
Throughout the Himalayan thrust belt, klippen of questionable tectonostratigraphic affinity occur atop Lesser Himalayan rocks. Integrated U-Pb ages, Hf isotopic, and whole rock trace element data establish that the Askot klippe, in northwest India, is composed of Paleoproterozoic lower Lesser Himalayan rocks, not Greater Himalayan rocks, as previously interpreted. The Askot klippe consists of 1857 ± 19 Ma granite-granodiorite gneiss, coeval 1878 ± 19 Ma felsic volcanic rock, and circa 1800 Ma Berinag quartzite, representing a small vestige of a Paleoproterozoic (circa 1850 Ma) continental arc, formed on northern margin of the north Indian cratonic block. Detrital zircon from Berinag …