Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- Western Michigan University (19480)
- University of Kentucky (10980)
- University of Nebraska - Lincoln (4541)
- University of South Florida (1881)
- China Coal Technology and Engineering Group (CCTEG) (1822)
-
- Department of Primary Industries and Regional Development, Western Australia (1674)
- Utah State University (1565)
- TÜBİTAK (917)
- Missouri University of Science and Technology (782)
- University of Arkansas, Fayetteville (769)
- Portland State University (671)
- Boise State University (667)
- Old Dominion University (666)
- University of Nevada, Las Vegas (521)
- University of Texas Rio Grande Valley (520)
- Montana Tech Library (496)
- Western Kentucky University (496)
- University of Colorado Law School (481)
- University of North Dakota (448)
- Louisiana State University (427)
- University of New Mexico (402)
- Montclair State University (387)
- Central Washington University (368)
- City University of New York (CUNY) (315)
- University of Texas at El Paso (315)
- University of South Carolina (280)
- Michigan Technological University (254)
- Brigham Young University (240)
- University of Texas at Arlington (237)
- University of New Hampshire (230)
- Keyword
-
- Western Australia (1183)
- Geology (902)
- Grains and field crops (625)
- Groundwater (623)
- Nebraska (589)
-
- Climate change (464)
- Grazing (407)
- Geochemistry (403)
- Soil (372)
- Hydrology (359)
- Montana (326)
- Nitrogen (323)
- Kentucky (302)
- Remote sensing (284)
- Salinity (282)
- Water quality (282)
- Drought (277)
- Utah (272)
- Water (240)
- Karst (234)
- Geophysics (228)
- Alfalfa (223)
- Climate (219)
- Hydrogeology (215)
- Phosphorus (213)
- Geomorphology (205)
- Stratigraphy (205)
- Agriculture (204)
- Irrigation (202)
- United States (191)
- Publication Year
- Publication
-
- Legacy Scout Tickets from Pure Oil Company (11044)
- IGC Proceedings (1977-2023) (9261)
- Thin Sections (6677)
- Coal Geology & Exploration (1822)
- Legacy Color Lithology Strip Logs (1152)
-
- United States Geological Survey: Staff Publications (1026)
- Turkish Journal of Earth Sciences (917)
- Conservation and Survey Division: Faculty and Staff Publications (901)
- International Journal of Speleology (890)
- Theses and Dissertations (835)
- Department of Earth and Atmospheric Sciences: Faculty Publications (673)
- Experimental Summaries - Plant Research (668)
- Masters Theses (591)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (454)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (429)
- Bachelors Theses and Reports, 1928 - 1970 (423)
- Geosciences Faculty Publications and Presentations (399)
- Faculty Publications (384)
- Kentucky Alfalfa and Stored Forage Conference (382)
- School of Geosciences Faculty and Staff Publications (355)
- Dissertations and Theses (343)
- Earth and Planetary Sciences ETDs (343)
- Graduate Theses and Dissertations (339)
- Electronic Theses and Dissertations (325)
- Memorandum (316)
- Resource management technical reports (315)
- Open Access Theses & Dissertations (294)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (280)
- USF Tampa Graduate Theses and Dissertations (272)
- Department of Earth and Environmental Studies Faculty Scholarship and Creative Works (266)
- Publication Type
Articles 46711 - 46740 of 59555
Full-Text Articles in Entire DC Network
Adaptive Resource Management And The Value Of Information, Byron K. Williams, Mitchell J. Eaton, David R. Breininger
Adaptive Resource Management And The Value Of Information, Byron K. Williams, Mitchell J. Eaton, David R. Breininger
United States Geological Survey: Staff Publications
The value of information is a general and broadly applicable concept that has been used for several decades to aid in making decisions in the face of uncertainty. Yet there are relatively few examples of its use in ecology and natural resources management, and almost none that are framed in terms of the future impacts of management decisions. In this paper we discuss the value of information in a context of adaptive management, in which actions are taken sequentially over a timeframe and both future resource conditions and residual uncertainties about resource responses are taken into account. Our objective is …
Comment On ‘‘An Unconfined Groundwater Model Of The Death Valley Regional Flow System And A Comparison To Its Confined Predecessor’’ By R.W.H. Carroll, G.M. Pohll And R.L. Hershey [Journal Of Hydrology 373/3–4, Pp. 316–328], Claudia C. Faunt, Alden M. Provost, Mary C. Hill, Wayne R. Belcher
Comment On ‘‘An Unconfined Groundwater Model Of The Death Valley Regional Flow System And A Comparison To Its Confined Predecessor’’ By R.W.H. Carroll, G.M. Pohll And R.L. Hershey [Journal Of Hydrology 373/3–4, Pp. 316–328], Claudia C. Faunt, Alden M. Provost, Mary C. Hill, Wayne R. Belcher
United States Geological Survey: Staff Publications
Carroll et al. (2009) state that the United States Geological Survey (USGS) Death Valley Regional Flow System (DVRFS) model, which is based on MODFLOW, is ‘‘conceptually inaccurate in that it models an unconfined aquifer as a confined system and does not simulate unconfined drawdown in transient pumping simulations.’’ Carroll et al. (2009) claim that ‘‘more realistic estimates of water availability’’ can be produced by a SURFACT-based model of the DVRFS that simulates unconfined groundwater flow and limits withdrawals from wells to avoid excessive drawdown. Differences in results from the original MODFLOW- based model and the SURFACT-based model stem primarily from …
Airborne Electromagnetic Surveys For 3d Geological Mapping, Jared D. Abraham, James C. Cannia
Airborne Electromagnetic Surveys For 3d Geological Mapping, Jared D. Abraham, James C. Cannia
United States Geological Survey: Staff Publications
The U.S. Geological Survey and its partners have collaborated to create 3D geologic maps for areas of the North and South Platte River valleys, including Lodgepole Creek, in western Nebraska using airborne electromagnetic surveys. The objective of the surveys is to map the 3D configuration of aquifers and bedrock topography created by the paleochannels of the ancestral Platte River. The ultimate goal is to gain a new understanding of groundwater–surface-water relationships to improve water management decisions through the use of groundwater management models. This goal was not achievable using traditional mapping methodologies, including surface geologic maps and borehole drilling logs. …
Evolution Of Large Carnivores During The Mid-Cenozoic Of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae) Robert M., Robert M. Hunt Jr.
Evolution Of Large Carnivores During The Mid-Cenozoic Of North America: The Temnocyonine Radiation (Mammalia, Amphicyonidae) Robert M., Robert M. Hunt Jr.
Department of Earth and Atmospheric Sciences: Faculty Publications
This study describes and summarizes the Temnocyoninae (Mammalia, Carnivora), a subfamily of amphicyonid carnivores of considerable diversity and singular ecomorphology within Cenozoic faunas of North America. In temnocyonines, we see the first carnivorans to occupy an ecological niche as large cursorial predators. The subfamily is confined to the Arikareean NALMA, ranging in age from the latest early Oligocene to the early Miocene. Distributed from the Pacific Northwest to the Great Plains and Florida, there are four genera (Temnocyon, Mammacyon, Delotrochanter n. gen., Rudiocyon n. gen.) and 12 species, of which eight are newly described (Temnocyon subferox …
Mass Wasting As A Geologic Hazard In The Province Of Salta, Argentina, William J. Wayne
Mass Wasting As A Geologic Hazard In The Province Of Salta, Argentina, William J. Wayne
Department of Earth and Atmospheric Sciences: Faculty Publications
The north-south orient ation ofthe mo unta inous part ofthe Province ofSalta form s a massive barrier to easy communication between the more populate d region in the central pan of the provin ce and the communities to the west. Routes follow deeply entrenched valleys th at are frequ entl y th e sites ofdebris flows that cause disruptions in th e flow of traffic during the months of December through March , wh en most of the precipitation of the region is recorded . The steep topography and the tecton ic settings have resulted in nearly 150 large landslides …
Distribution And Properties Of Vesicular Horizons In The Western United States, Judith K. Turk, Robert C. Graham
Distribution And Properties Of Vesicular Horizons In The Western United States, Judith K. Turk, Robert C. Graham
Conservation and Survey Division: Faculty and Staff Publications
Vesicular horizons are thin (usuallycm) surface or near-surface horizons characterized by the predominance of vesicular porosity. Th ey are widespread in arid and semiarid lands, occurring on every continent and covering 156,000 km2 of the western United States. Vesicular horizons have critical implications for management due to their role in controlling surface hydrology and dust mobilization. Th is study evaluates the distribution and varia-tion in expression of vesicular horizons across the western United States using the soil databases available from the USDA. A vesicular horizon index (VHI) that incorporates vesicular horizon thickness and the size and quantity of vesicular pores …
Annual Outflow Of Water From Nebraska, 1950 - 2010, S. Olafsen-Lackey
Annual Outflow Of Water From Nebraska, 1950 - 2010, S. Olafsen-Lackey
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Reference List For Describing Cuttings And Cores Of Sediments And Sedimentary Rocks In Nebraska, J. T. Korus, Robert Matthew Joeckel, P. R. Hanson, J. W. Goeke, S. O. Lackey, M. B. Burbach
Reference List For Describing Cuttings And Cores Of Sediments And Sedimentary Rocks In Nebraska, J. T. Korus, Robert Matthew Joeckel, P. R. Hanson, J. W. Goeke, S. O. Lackey, M. B. Burbach
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Estimating Hydraulic Conductivity For The Martian Subsurface Based On Drainage Patterns — A Case Study In The Mare Tyrrhenum Quadrangle, Wei Luo, Bartosz Grudzinski, Darryll T. Pederson
Estimating Hydraulic Conductivity For The Martian Subsurface Based On Drainage Patterns — A Case Study In The Mare Tyrrhenum Quadrangle, Wei Luo, Bartosz Grudzinski, Darryll T. Pederson
Department of Earth and Atmospheric Sciences: Faculty Publications
Hydraulic conductivity K, as the coefficient of proportionality in Darcy’s Law, is critical in understanding the past Martian hydrologic cycle, climate, and landform evolution. However, K and its spatial variability on Mars are thus far poorly constrained due to lack of accessibility. Using an innovative method based on surface drainage dissection patterns, which has been successfully tested in the Oregon Cascades on Earth, we estimated K in the Mare Tyrrhenum Quadrangle on Mars. The basic assumption is that under long-term dynamic equilibrium conditions, the overall dissection pattern in a watershed as reflected in drainage density is controlled by the …
Late Pleistocene Dune Activity In The Central Great Plains, Usa, Joseph A. Mason, James B. Swinehart, Paul R. Hanson, David Loope, Ronald J. Goble, Xiaodong Miao, Rebecca L Schmeisser
Late Pleistocene Dune Activity In The Central Great Plains, Usa, Joseph A. Mason, James B. Swinehart, Paul R. Hanson, David Loope, Ronald J. Goble, Xiaodong Miao, Rebecca L Schmeisser
Department of Earth and Atmospheric Sciences: Faculty Publications
Stabilized dunes of the central Great Plains, especially the megabarchans and large barchanoid ridges of the Nebraska Sand Hills, provide dramatic evidence of late Quaternary environmental change. Episodic Holocene dune activity in this region is now well-documented, but Late Pleistocene dune mobility has remained poorly documented, despite early interpretations of the Sand Hills dunes as Pleistocene relicts. New optically stimulated luminescence (OSL) ages from drill cores and outcrops provide evidence of Late Pleistocene dune activity at sites distributed across the central Great Plains. In addition, Late Pleistocene eolian sands deposited at 20–25 ka are interbedded with loess south of the …
Electron-Positron Beams From Terrestrial Lightning Observed With Fermi Gbm, Michael S. Briggs, Joseph R. Dwyer
Electron-Positron Beams From Terrestrial Lightning Observed With Fermi Gbm, Michael S. Briggs, Joseph R. Dwyer
Aerospace, Physics, and Space Science Faculty Publications
Terrestrial Gamma-ray Flashes (TGFs) are brief pulses of energetic radiation observed in low-earth orbit. They are associated with thunderstorms and lightning and have been observed both as gamma-ray and electron flashes depending on the position of the spacecraft with respect to the source. While gamma-ray TGFs are detected as short pulses lasting less than 1 ms, most TGFs seen by the Fermi Gamma-ray Burst Monitor (GBM) with durations greater than 1 ms are, instead, the result of electrons traveling from the sources along geomagnetic field lines. We perform spectral analysis of the three brightest electron TGFs detected by GBM and …
The Rarity Of Terrestrial Gamma-Ray Flashes, D. M. Smith, Michael E. Splitt, Steven M. Lazarus, W. Ulrich, Jospeh R. Dwyer
The Rarity Of Terrestrial Gamma-Ray Flashes, D. M. Smith, Michael E. Splitt, Steven M. Lazarus, W. Ulrich, Jospeh R. Dwyer
Aerospace, Physics, and Space Science Faculty Publications
We report on the first search for Terrestrial Gamma-ray Flashes (TGFs) from altitudes where they are thought to be produced. The Airborne Detector for Energetic Lightning Emissions (ADELE), an array of gamma-ray detectors, was flown near the tops of Florida thunderstorms in August/September 2009. The plane passed within 10 km horizontal distance of 1213 lightning discharges and only once detected a TGF. If these discharges had produced TGFs of the same intensity as those seen from space, every one should have been seen by ADELE. Separate and significant nondetections are established for intracloud lightning, negative cloud-to-ground lightning, and narrow bipolar …
Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton
Fate Of Stable Isotope Label During Predation Of 15N-Tagged Wild-Type Escherichia Coli By Protozoa, Ashley M. Barton
University of Kentucky Master's Theses
Currently, bacterial movement in karst aquifers is not well understood. Use of stable isotopes to label non-pathogenic Escherichia coli as a particulate groundwater tracer in karst systems has been examined in previous studies. Loss of the stable isotope signal is anticipated in traces greater than 500 m in length. Potential loss of 15N due to predation by protozoa was examined. Filter-sterilized water from Royal Spring in Georgetown, Kentucky, was inoculated with a mixture of either Tetrahymena pyriformis or Colpoda steinii and 15N-enriched E. coli and stored in the dark at 14°C. Samples were analyzed for their nitrogen isotope …
Uis Mapping Grades, Ph. Häuselmann
Uis Mapping Grades, Ph. Häuselmann
International Journal of Speleology
No abstract provided.
Editorial, Jo De Waele
Receiver Function Studies Of Crustal Structure, Composition, And Evolution Beneath The Afar Depression, Ethiopia, Sattam A. Almadani
Receiver Function Studies Of Crustal Structure, Composition, And Evolution Beneath The Afar Depression, Ethiopia, Sattam A. Almadani
Doctoral Dissertations
"The dissertation utilizes a set of sophisticated computer programs developed at the Geophysics group at Missouri S&T to characterize crustal properties beneath the Afar Depression in Ethiopia where extensional tectonics dominates. In this study, measurements of crustal thickness (H), crustal mean Vp/Vs [which is related to Poisson's ratio (Σ)], and the sharpness of the Moho (R) were determined using teleseismic data from 18 broadband seismic sensors that we deployed along a profile of 250 km long with a station spacing of ~ 10 km. The stations had been recording continuously for an entire year from December 2009 until December 2010. …
Applied Palynology: Multidisciplinary Case Studies From Egypt, Gulf Of Mexico And Usa, Mohamed K. Zobaa
Applied Palynology: Multidisciplinary Case Studies From Egypt, Gulf Of Mexico And Usa, Mohamed K. Zobaa
Doctoral Dissertations
"Various applications of palynology have been used to study case studies from four different parts of the world, namely northern Egypt, offshore Gulf of Mexico, eastern Tennessee (USA), and New Orleans, Louisiana (USA). In these case studies, palynomorphs (spores, pollen, dinoflagellate cysts, and algae) have been utilized to define zones of hydrocarbon potential, reconstruct paleoenvironmental and paleoclimatic conditions, constrain the ages of the studied rock sequences, and express its potential as a replacement proxy for some expensive organic geochemical analyses. The ability to detect past hurricane activities and their associated damage to the geologic record is here presented as a …
A Geological And Geophysical Study Of The Tendaho Graben In The Afar Depression, Ethiopia: Insights Into Transitional Continental Rifting, David Lee Bridges
A Geological And Geophysical Study Of The Tendaho Graben In The Afar Depression, Ethiopia: Insights Into Transitional Continental Rifting, David Lee Bridges
Doctoral Dissertations
"A detailed magnetic and gravity study across the Tendaho Graben (the Red Sea propagator within the Afar Depression, Ethiopia) revealed features that can best be interpreted as a continental rift undergoing oceanization. This NW-trending extensional structure is ~50 km wide and it is confined within well-developed NW-trending boarder faults that deform the 2 km thick and ~ 2 Ma basaltic flows of the Afar Stratoids. The age of the basaltic flows becomes progressively younger inward from the boarder faults until it reaches ~30,000 years close to the rift axis. The central part of the Tendaho Graben is characterized by a …
Crustal Structure And Evolution Beneath The Colorado Plateau And The Southern Basin And Range Province, Lamuail Bashir
Crustal Structure And Evolution Beneath The Colorado Plateau And The Southern Basin And Range Province, Lamuail Bashir
Doctoral Dissertations
"Stacking of about 15,500 P-to-S receiver functions recorded at 72 USArray and other broadband seismic stations placed on the Colorado Plateau and the SBRP in Arizona revealed systematic spatial variations in crustal Vp/Vs, crustal thickness and amplitude of P-to-S converted phases. Our results reveal that the BRP is characterized by a thin crust (28.2 ± 0.5 km), a mean Vp/Vs of 1.761 ± 0.014 and a mean amplitude (R) of P - to - S converted wave (relative to that of the direct P wave) of 0.181 ± 0.014 that are similar to a typical continental crust, consistent with the …
The Origin Of Quartz Glomerocrysts: Insights From The Rhyolite Dike At Medicine Park, Ok, Sedeg Ahmed E. Ahmed
The Origin Of Quartz Glomerocrysts: Insights From The Rhyolite Dike At Medicine Park, Ok, Sedeg Ahmed E. Ahmed
Masters Theses
"The origin of quartz glomerocrysts a distinctive petrographic feature of the rhyolite dike in Medicine Park, Oklahoma, was investigated using transmitted light and cathodoluminescence microscopy to determine if quartz glomerocrysts formed during quartz crystallization or during quartz dissolution. Quartz glomerocrysts are typically comprised of two to six individual phenocrysts of quartz and commonly exhibit subhedral partially embayed crystal forms with very rare euhedral phenocrysts in both glomerocrysts and individual quartz phenocrysts. The size range of the individual quartz phenocrysts are 0.08mm to 1.7mm while the size range is 0.08mm to 3.25mm for quartz glomerocrysts . Cathodoluminescence revealed that individual quartz …
Evaluating The Effectiveness Of Multi-Spectral Remote Sensing Data For Lithological Mapping In Arid Regions: A Quantitative Approach With Examples From The Makkah Neoproterozoic Region, Saudi Arabia, Nawwaf Awad Al Muntshry
Evaluating The Effectiveness Of Multi-Spectral Remote Sensing Data For Lithological Mapping In Arid Regions: A Quantitative Approach With Examples From The Makkah Neoproterozoic Region, Saudi Arabia, Nawwaf Awad Al Muntshry
Masters Theses
"This work quantitatively evaluates the effectiveness of multi-spectral remote sensing data for geological mapping in arid regions. For this, Landsat Thematic Mapper (TM) data covering part of the Neoproterozoic Arabian Shield around the Makkah region in Saudi Arabia are used. The Makkah region is dominated by a variety of layered and intrusive rocks covered by unconsolidated sediments. The Landsat TM data have six spectral bands in the visible and near infrared (VNIR) and shortwave infrared (SWIR) with thirty meters spatial resolution.
The Optimum Index Factor (OIF) has been computed to determine the best Red-Green-Blue (RGB) band combination emerging from the …
Designing And Using Virtual Field Environments To Enhance And Extend Field Experience In Professional Development Programs In Geology For K-12 Teachers, Frank Douglas Granshaw
Designing And Using Virtual Field Environments To Enhance And Extend Field Experience In Professional Development Programs In Geology For K-12 Teachers, Frank Douglas Granshaw
Dissertations and Theses
Virtual reality (VR) is increasingly used to acquaint geoscience novices with some of the observation, data gathering, and problem solving done in actual field situations by geoscientists. VR environments in a variety of forms are used to prepare students for doing geologic fieldwork, as well as to provide proxies for such experience when venturing into the field is not possible. However, despite increased use of VR for these purposes, there is little research on how students learn using these environments, how using them impacts student field experience, or what constitutes effective design in light of emerging theories of geocognition.
To …
Potential For Speciation In Mammals Following Vast, Late Miocene Volcanic Interruptions In The Pacific Northwest, Ryan Thomas Mckenna
Potential For Speciation In Mammals Following Vast, Late Miocene Volcanic Interruptions In The Pacific Northwest, Ryan Thomas Mckenna
Dissertations and Theses
The impact of large-scale volcanic eruptions on landscapes can affect many processes ranging from interrupting or redirecting regional soil forming processes and hydrological systems to generating temporary changes in global climate. Though more studies exist every year, less is known of the direct impact of large-scale volcanic eruptions on ecosystems and extinction, while even less is known of their impact on speciation. In deposits throughout the Pacific Northwest a special combination and association of volcanic magnitude with palaeoecological yield frequently presents unique prospects for inquiry. In this study, particular attention is given to large, late Miocene ash-flow tuffs of central …
On Constrained Optimization Schemes For Joint Inversion Of Geophysical Datasets, Uram Anibal Sosa Aguirre
On Constrained Optimization Schemes For Joint Inversion Of Geophysical Datasets, Uram Anibal Sosa Aguirre
Open Access Theses & Dissertations
In the area of geological sciences, there exist several experimental techniques used to advance in the understanding of the Earth. We implement a joint inversion least-squares (LSQ) algorithm to characterize one dimensional Earth's structure by using seismic shear wave velocities as a model parameter. We use two geophysical datasets sensitive to shear velocities, namely Receiver Function and Surface Wave dispersion velocity observations, with a choice of an optimization method: Truncated Singular Value Decomposition (TSVD) or Primal-Dual Interior-Point (PDIP). The TSVD and the PDIP methods solve a regularized unconstrained and a constrained minimization problem, respectively. Both techniques include bounds into the …
Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah
Implications Of Surface Runoff Recharge In Semi-Arid Regions On Groundwater Sustainability, Omar M. Al-Qudah
Open Access Theses & Dissertations
Amargosa Desert, Nevada regional groundwater studies show that the surface runoff infiltration occurring in the arroyos following runoff producing storms, and this infiltration is considered to be a major source of groundwater recharge. Groundwater infiltration through alluvium was investigated in the Amargosa Desert using borehole drill cuttings, groundwater chemistry, and applying a novel method for collecting runoff water. The sampling process included sediment, precipitation, and runoff water. In total, 176 runoff, 182 sediment, and 45 precipitation samples were collected between January, 2009 and January, 2011.Water chemistry, chloride concentrations, and stable isotopes of water collected from specially designed runoff samplers, placed …
Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas
Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas
Open Access Theses & Dissertations
The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, an important petroleum province within south-central Alaska. A primary goal in the research is to test several plausible models of structure along the Border Ranges Fault System using a novel three-dimensional inversion utilizing gravity and magnetic data, constrained with other geophysical, borehole and surface geological information. This research involves the development of inversion modeling software using a Borland C++ compiler as part of the Rapid Application Development (RAD) Studio. The novel inversion approach directly models known geology, and "a priori" uncertainties on the geologic model to allow …
The East Jhomolari Fault System And The Timing Of East-West Extension In Northwest Bhutan, John Matthew Cannon
The East Jhomolari Fault System And The Timing Of East-West Extension In Northwest Bhutan, John Matthew Cannon
Open Access Theses & Dissertations
This investigation documents a little known, regionally significant, high angle, southeast dipping, system of normal faults in northwest Bhutan, the East Jhomolari Fault System (EJFS). The EJFS trends parallel to the Yadong Gulu rift (YG) and can be traced from Mt. Jhomolari to the northern border with Tibet. This fault zone has been demonstrably active since the last glacial maximum and there is geomorphic evidence of Holocene activity on some fault segments. The structurally lowest EJFS fault, the Lingshi fault appears on some published maps, but the full geographic extent, displacement, onset of faulting, and most recent activity have not …
A Proposed Epithermal Model For The High Grade District, California, Michael Nicholas Feinstein
A Proposed Epithermal Model For The High Grade District, California, Michael Nicholas Feinstein
Open Access Theses & Dissertations
A historic gold mining district in northeastern California has not been incorporated into the global knowledge base for precious metal vein deposits. This study collected various data types which are important characteristics in the classification and understanding of vein deposits. The High Grade District (HGD) is a gold mining site located in the northeast corner of Modoc County, California, in the Warner Mountains. The Warner Mountains are composed of Tertiary eruptive centers, cropping out between valleys formed through extensional tectonics. Mineralization of the HGD displays abundant silicification, adularia, and gold; these characteristics are sufficient to classify mineralization as low-sulfidation epithermal …
Gpu Based Parallel Smoothing Of Seismic Tomography Models, Ivan Gris
Gpu Based Parallel Smoothing Of Seismic Tomography Models, Ivan Gris
Open Access Theses & Dissertations
Three-dimensional models of the velocity structure of the Earth's crust are an important and relevant factor for several types of analyses across disciplines. Crustal velocity models are also commonly used to analyze and search for different materials of interest or to determine and differentiate many aspects of life on Earth during different eras.
Seismic tomography techniques, both in two and three dimensions, perform image reconstruction of the crust of the Earth. Seismic tomography algorithms can calculate crustal velocity structure through inversion of traveltimes of seismic waves produced by natural events, such as earthquakes, or controlled source experiments, such as explosions. …
The Impact Of Sulfide Mineral Weathering On The Isotopic Signatures Of Fe And Cu In Metal-Rich Streams, Ana Lourdes Gutierrez
The Impact Of Sulfide Mineral Weathering On The Isotopic Signatures Of Fe And Cu In Metal-Rich Streams, Ana Lourdes Gutierrez
Open Access Theses & Dissertations
The oxidative weathering of sulfide minerals, like pyrite, at the Earth's surface controls the formation of acid mine drainage sites as well as the Fe isotope composition of these areas and the main processes taken place. In this study, water and rock samples were collected from acidic drainages (most from abandoned mining sites) from the St. Juan Mountains in Colorado. The water samples were measured in-situ for dissolved oxygen, dissolved Fe(II), pH, and conductivity. Filtered acidified, unfiltered acidified, and Fe-oxide samples were analyzed for their metal concentrations. Ion-exchange chromatography was applied to both water and digested oxide fractions in order …