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1450 full-text articles. Page 1 of 36.

A. Overview Of The Flathead Lake Seismic Survey, Robert W. Lankston 2017 University of Montana - Missoula

A. Overview Of The Flathead Lake Seismic Survey, Robert W. Lankston

1970 Flathead Lake Seismic Survey

This book contains a summary of the key phases of acquisition and use of the reflection seismic data that were collected in 1970 in Flathead Lake and the evolution of the physical and digital archives of that seismic project.


Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. McNamara 2017 Boise State University

Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. Mcnamara

James P. McNamara

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 ...


Particle Dynamics In The Rising Plume At Piccard Hydrothermal Field, Mid-Cayman Rise, Meg Estapa, J. A. Breier, C R. German 2017 Skidmore College

Particle Dynamics In The Rising Plume At Piccard Hydrothermal Field, Mid-Cayman Rise, Meg Estapa, J. A. Breier, C R. German

Meg Estapa

Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper ...


Observations Of Carbon Export By Small Sinking Particles In The Upper Mesopelagic, Colleen A. Durkin, Meg Estapa, Ken O. Buesseler 2017 Skidmore College

Observations Of Carbon Export By Small Sinking Particles In The Upper Mesopelagic, Colleen A. Durkin, Meg Estapa, Ken O. Buesseler

Meg Estapa

Carbon and nutrients are transported out of the surface ocean and sequestered at depth by sinking particles. Sinking particle sizes span many orders of magnitude and the relative influence of small particles on carbon export compared to large particles has not been resolved. To determine the influence of particle size on carbon export, the flux of both small (11–64 μm) and large (> 64 μm) particles in the upper mesopelagic was examined during 5 cruises of the Bermuda Atlantic Time Series (BATS) in the Sargasso Sea using neutrally buoyant sediment traps mounted with tubes containing polyacrylamide gel layers and tubes ...


Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. McNamara 2017 Boise State University

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 ...


An Investigation Into The Origin, Composition, And Commercial Significance Of A Sedimentary Subsalt Formation: Keathley Canyon, Gulf Of Mexico, David Aaron Brassieur 2016 University of New Orleans, New Orleans

An Investigation Into The Origin, Composition, And Commercial Significance Of A Sedimentary Subsalt Formation: Keathley Canyon, Gulf Of Mexico, David Aaron Brassieur

University of New Orleans Theses and Dissertations

Sub-salt oil and gas formations in deep-water northern Gulf of Mexico are high priority targets. Advances in seismic processing allow for high-resolution, below-salt imaging. Understanding the modes of salt emplacement provide insight into sub-salt traps and potential drilling hazards.

A sub-salt sedimentary unit lies in the Keathley Canyon protraction. Autosutures created the transport-parallel lineaments of the upper surface of the unit. In addition, highly variable sediment aggradation rates created ramps, flats, and basal cutoffs along the base of the allochthon as salt and sediment competed for space. Seismic models identify modes of salt emplacement, salt/sediment interactions, and mechanisms responsible ...


Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub 2016 Stephen F Austin State University

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas ...


Using Near-Infrared Photography To Better Study Snow Microstructure And Its Variability Over Time And Space, Jesse Raymond Dean 2016 Boise State University

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 ...


Using Infrasound Waves To Monitor Tropospheric Weather And Crater Morphology Changes, Hugo David Ortiz 2016 Boise State University

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 ...


Microstructural Analysis Of Thermoelastic Response, Nonlinear Creep, And Pervasive Cracking In Heterogeneous Materials, Alden C. Cook 2016 University of Maine

Microstructural Analysis Of Thermoelastic Response, Nonlinear Creep, And Pervasive Cracking In Heterogeneous Materials, Alden C. Cook

Electronic Theses and Dissertations

This dissertation is concerned with the development of robust numerical solution procedures for the generalized micromechanical analysis of linear and nonlinear constitutive behavior in heterogeneous materials. Although the methods developed are applicable in many engineering, geological, and materials science fields, three main areas are explored in this work. First, a numerical methodology is presented for the thermomechanical analysis of heterogeneous materials with a special focus on real polycrystalline microstructures obtained using electron backscatter diffraction techniques. Asymptotic expansion homogenization and finite element analysis are employed for micromechanical analysis of polycrystalline materials. Effective thermoelastic properties of polycrystalline materials are determined and compared ...


Unblocking Temperatures Of Viscous Remanent Magnetism In Displaced Granitic Boulders, Icicle Creek Glacial Moraines (Washington, Usa), Juliet G. Crider, Danika M. Globokar, Russ F. Burmester, Bernard A. Housen 2016 Western Washington University

Unblocking Temperatures Of Viscous Remanent Magnetism In Displaced Granitic Boulders, Icicle Creek Glacial Moraines (Washington, Usa), Juliet G. Crider, Danika M. Globokar, Russ F. Burmester, Bernard A. Housen

Bernard A. Housen

Viscous remanent magnetization (VRM) may partially overprint original magnetization in rocks displaced by geomorphic events. An established theoretical relationship between the time and temperature of acquisition of VRM and the time and temperature of demagnetization suggests that laboratory demagnetization (unblocking) of VRM can be used to estimate the displacement age of rocks. We test this hypothesis at four nested glacial moraines in the Icicle Creek drainage of central Washington, the ages of which were previously determined by cosmogenic surface exposure dating. The moraines are composed primarily of granodiorite boulders, and magnetic remanence is carried dominantly by magnetite. Both the maximum ...


Unblocking Temperatures Of Viscous Remanent Magnetism In Displaced Granitic Boulders, Icicle Creek Glacial Moraines (Washington, Usa), Juliet G. Crider, Danika M. Globokar, Russ F. Burmester, Bernard A. Housen 2016 Western Washington University

Unblocking Temperatures Of Viscous Remanent Magnetism In Displaced Granitic Boulders, Icicle Creek Glacial Moraines (Washington, Usa), Juliet G. Crider, Danika M. Globokar, Russ F. Burmester, Bernard A. Housen

Russ R. Burmester

Viscous remanent magnetization (VRM) may partially overprint original magnetization in rocks displaced by geomorphic events. An established theoretical relationship between the time and temperature of acquisition of VRM and the time and temperature of demagnetization suggests that laboratory demagnetization (unblocking) of VRM can be used to estimate the displacement age of rocks. We test this hypothesis at four nested glacial moraines in the Icicle Creek drainage of central Washington, the ages of which were previously determined by cosmogenic surface exposure dating. The moraines are composed primarily of granodiorite boulders, and magnetic remanence is carried dominantly by magnetite. Both the maximum ...


Paleomagnetism Of The Patagonian Plateau Basalts, Southern Chile And Argentina, Robert F. Butler, Francisco Herve, Francisco Munizaga, Myurl E. Beck Jr., Russell F. Burmester, Eduardo S. Oviedo 2016 University of Portland

Paleomagnetism Of The Patagonian Plateau Basalts, Southern Chile And Argentina, Robert F. Butler, Francisco Herve, Francisco Munizaga, Myurl E. Beck Jr., Russell F. Burmester, Eduardo S. Oviedo

Russ R. Burmester

A total of 505 paleomagnetic samples were collected from 65 sites (volcanic flows) of the Patagonian plateau basalts at four locations in southern Chile and Argentina. K/Ar analyses indicate that 38 flows from two locations form a Late Cretaceous group (64–79 Ma), while the remaining 27 flows are Eocene in age (42–56 Ma). Progressive demagnetization indicates that a characteristic remanent magnetization (ChRM) has been successfully isolated from 59 flows. Rock-magnetic properties and analysis of ChRM directions within and between sites allow the secure inference that the ChRM is a thermoremanent magnetization acquired during original cooling. The Eocene ...


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 2016 Lancaster University

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

Warren Barrash

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 ...


Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. McKay, John Charles Priscu 2016 Portland State University

Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu

Geology Faculty Publications and Presentations

A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thick-ness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface ra-diative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thick-ness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of ...


The Application Of Geophysical Inversion Techniques To The Nechalacho Rare Earth Element Deposit, Nt, Derek W. Kouhi 2016 The University of Western Ontario

The Application Of Geophysical Inversion Techniques To The Nechalacho Rare Earth Element Deposit, Nt, Derek W. Kouhi

Electronic Thesis and Dissertation Repository

The Nechalacho deposit is a world-class rare earth element deposit located in the Thor Lake region approximately 100 kilometers southwest of Yellowknife, NT, Canada. Located within the Blatchford Lake Intrusion Complex, this deposit has the potential to be a large-scale economic asset due to its relatively shallow and sub-horizontal geometry. In this study, geophysical inversion techniques are used to model subsurface magnetic susceptibility and density in order to delineate the deposit. Isolated and joint inversion of both magnetic and gravity data provides similar models. Each inversion procedure delineates a shallow, sub-horizontal layer of high susceptibility and density in approximately the ...


The Geophysical Kitchen Sink Approach To Improving Our Understanding Of Volcano-Tectonic Interactions, Ophelia Ann George 2016 University of South Florida

The Geophysical Kitchen Sink Approach To Improving Our Understanding Of Volcano-Tectonic Interactions, Ophelia Ann George

Graduate Theses and Dissertations

A multi-prong approach was taken in this dissertation to understand volcanic processes from both a long-term and more immediate hazard perspective. In the long-term, magma sources within the crust may produce measurable surficial response and long-wavelength gravity anomalies that provide information about the extent and depth of this magma. Long-term volcanic hazard forecasting is also improved by developing as complete a record as possible of past events. In the short-term, a long-standing question has been on the casting of precursory volcanic activity in terms of future volcanic hazards. Three studies are presented in this dissertation to address these issues. Inversion ...


Biotic Paleothermometry Constrains On Arctic Plates Reconstructions: Carboniferous And Permian (Zhokhov Island, De-Longa Group Islands, New Siberian Archipelago), Vladimir I. Davydov 2016 Boise State University

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 ...


Mineral Physics Modeling Of The Effect Of Water On Crustal Seismic Velocity Ratios, Eric Lyman 2016 Utah State University

Mineral Physics Modeling Of The Effect Of Water On Crustal Seismic Velocity Ratios, Eric Lyman

Physics Capstone Project

This research explores the relationship between the presence of water (H2O) in the make up of rocks and minerals (specifically quartz) at different levels in the crust. The relationships were calculated using Perple_x software to adjust the level of the different chemical and mineral make up of the rock. The densities were calculated using the velocity of primary waves and shear waves as collected by Tony Lowry. There seems to be at least a casual link between water content and quartz content.


Isolating Retrograde And Prograde Rayleigh-Wave Modes Using A Polarity Mute, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell, Paul Michaels 2016 Boise State University

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 ...


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