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Articles 26011 - 26040 of 29959

Full-Text Articles in Geology

Simulation Of Groundwater Flow In Cache Valley, Utah And Idaho, Barry Myers May 2003

Simulation Of Groundwater Flow In Cache Valley, Utah And Idaho, Barry Myers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A groundwater model of Cache Valley was created using MODFLOW. Steady-state calibration of the model demonstrated that recharge to the lower confined aquifer may occur along the margin of the valley that borders the Wellsville Mountains and the Bear River Range. Steady-state calibration also showed that discharge from the unconfined aquifer may occur along the eastern and western margins of the valley in both the Utah and the Idaho portions of the valley.

Two simulations were run with increased pumping of 3 5 cubic feet per second (1 cubic meter per second) from the principal aquifer. The first simulation was …


One-Dimensional Modeling Of Bromide Tracer And Trichloroethylene Transport Based On Laboratory Experiments In Vertical Soil Columns, Keri L. Murch May 2003

One-Dimensional Modeling Of Bromide Tracer And Trichloroethylene Transport Based On Laboratory Experiments In Vertical Soil Columns, Keri L. Murch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Enhanced biodegradation using carbon donor and microbial addition is being considered as a possible remediation technique for a trichloroethylene (TCE) contaminated area in Sunset, Utah, west of the source area on Hill Air Force Base. As a precursor to any in situ remediation attempts, several laboratory treatability experiments are being conducted, including the construction of microcosms and flow-through columns. Nine large-scale flow-through columns were built using site groundwater and aquifer material. Bromide tracer tests were conducted to establish and understand the hydraulic conditions within the columns prior to the commencement of the TCE biodegradation experiments. Four predictive models were created …


Geology Of The Deseret Peak East 7.5' Quadrangle, Tooele County, Utah, And Impacts For Hydrology Of The Region, Torrey J. Copfer May 2003

Geology Of The Deseret Peak East 7.5' Quadrangle, Tooele County, Utah, And Impacts For Hydrology Of The Region, Torrey J. Copfer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Detailed geologic mapping of the Deseret Peak East 7.5' Quadrangle yields new interpretations regarding the stratigraphy of the Oquirrh Basin, fault and fold geometry, and structural evolution of the region. The Stansbury Range consists of the north-south-trending Deseret anticline. Basal Mississippian units rest unconformably on Cambrian beds in the central part of the range. Paleozoic uplift, Mesozoic contraction, and Cenozoic extension have created a series of broad folds, large thrust faults, and several normal faults.

The area is dominated by bedrock springs, with the presence of abundant and thick Quaternary deposits unrelated to Pleistocene glaciation, burying drainages, and mantling hillslopes. …


The Middle Cambrian Wheeler Formation: Sequence Stratigraphy And Geochemistry Across A Ramp-To-Basin Transition, Elizabeth S. Langenburg May 2003

The Middle Cambrian Wheeler Formation: Sequence Stratigraphy And Geochemistry Across A Ramp-To-Basin Transition, Elizabeth S. Langenburg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Wheeler Formation is interpreted as having been deposited in the shallow ramp and deeper basin environments of the House Range embayment (HRE), presumably, during a single third-order sequence. In the Drum Mountains, the Wheeler Formation (295 m thick) is dominated by proximal and distal ramp deposits; at Marjum Pass, the Wheeler Formation (190m thick) is dominated by basinal shale deposits. The Wheeler Formation contains only one biozone marker; the first appearance of Ptyhagnostus atavus. Lack of other chronostratigraphic markers and distinctive stratal patterns in the basinal facies makes correlation along this ramp-to-basin transect difficult. Therefore, carbon-isotope …


Sequence Stratigraphy And Depositional Facies Of Lower Ordovician Cyclic Carbonate Rocks, Southern Missouri, U.S.A., Robert Brandon Overstreet, Francisca Oboh-Ikuenobe, Jay M. Gregg May 2003

Sequence Stratigraphy And Depositional Facies Of Lower Ordovician Cyclic Carbonate Rocks, Southern Missouri, U.S.A., Robert Brandon Overstreet, Francisca Oboh-Ikuenobe, Jay M. Gregg

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Lower Ordovician cyclic carbonate strata of southern Missouri were deposited in a warm, shallow, epeiric sea on a fully aggraded carbonate platform. Sedimentological characteristics distinguish the Jefferson City and Cotter dolomites from the underlying Gasconade and Roubidoux formations. Mixed carbonate-siliciclastic sedimentation characterizes the Roubidoux Formation, with sandstones accounting for up to 60% of sedimentation. The Gasconade, Jefferson City, and Cotter dolomites exhibit an increased occurrence of chalcedonic chert nodules in very similar shape and texture to the gypsum and anhydrite nodules common on modern sabkha supratidal flats. Casts of halite and ghosts of gypsum laths also exist in the Jefferson …


Depositional Characteristics Of 7Be And 210Pb In Southeastern Michigan, D. Mcneary, M. Baskaran Apr 2003

Depositional Characteristics Of 7Be And 210Pb In Southeastern Michigan, D. Mcneary, M. Baskaran

Environmental Science and Geology Faculty Research Publications

The depositional fluxes in the bulk and dry fallout as well as the concentrations of 7Be and 210Pb in aerosols were measured for a period of 17 months at Detroit, Michigan. The bulk depositional fluxes of 7Be and 210Pb varied between 3.11 and 63.0 dpm cm−2 yr−1 (mean of 11.4 dpm cm−2 yr−1) and 0.35 and 10.3 dpm cm−2 yr−1 (mean of 1.41 dpm cm−2 yr−1), respectively, and this variability in the depositional fluxes is attributed to the frequency and amount of precipitation and seasonal variations …


Water Transfers And Marketing In Nebraska, J Michaeil Jess Apr 2003

Water Transfers And Marketing In Nebraska, J Michaeil Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Geology, Groundwater Chemistry And Management Of The Dakota Aquifer In Nebraska, David C. Gosselin, F. Edwin Harvey, Charles A. Flowerday Apr 2003

Geology, Groundwater Chemistry And Management Of The Dakota Aquifer In Nebraska, David C. Gosselin, F. Edwin Harvey, Charles A. Flowerday

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


2003 Changes To Water Transfer Law In Nebraska - Addendum, J Michael Jess Apr 2003

2003 Changes To Water Transfer Law In Nebraska - Addendum, J Michael Jess

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Evidence For Small-Scale Mantle Convection In The Upper Mantle Beneath The Baikal Rift Zone, Stephen S. Gao, Kelly H. Liu, Paul M. Davis, Philip D. Slack, Yuliy A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov Apr 2003

Evidence For Small-Scale Mantle Convection In The Upper Mantle Beneath The Baikal Rift Zone, Stephen S. Gao, Kelly H. Liu, Paul M. Davis, Philip D. Slack, Yuliy A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Inversion of teleseismic P wave travel time residuals collected along a 1280-km-long profile traversing the Baikal rift zone (BRZ) reveals the existence of an upwarped lithosphere/asthenosphere interface, which causes a travel time delay of about 1 s at the rift axis ("central high"). An area with early arrivals relative to the stable Siberian platform of up to 0.5 s is observed on each side of the rift, about 200 km from the rift axis ("flank lows"). While the location of the central high is approximately fixed in the vicinity of the rift axis, those of the flank lows vary as …


The Influence Of Lithophysal Porosity On The In-Situ Stress-Strain Properties Of Topopah Spring Tuff, Bahri B. Avar, Moses Karakouzian, Amy J. Smiecinski Mar 2003

The Influence Of Lithophysal Porosity On The In-Situ Stress-Strain Properties Of Topopah Spring Tuff, Bahri B. Avar, Moses Karakouzian, Amy J. Smiecinski

Publications (YM)

Numerical analysis and a laboratory testing program were conducted in order to investigate the effect of lithophysal porosity on the elastic stress-strain properties of the lithophysae-rich tuff specimens and to find the locations of cavities in both analog and tuff specimens. In the first part of the study, a finite difference mesh containing circular holes was modeled for varying porosity ranges between 5 and 40% using commercially available software FLAG20' version 3.5. Elastic (Young's) modulus and Poisson's ratio were calculated for each setup and normalized with respect to matrix elastic modulus and Poisson's ratio. The moduli calculated through numerical analysis …


Enrichments Of 34s In Sulfide Minerals Of Deep-Water Marine Sediments Of The Blake Ridge, Offshore Southeastern United States, Kathryn G. Takacs, Walter S. Borowski Mar 2003

Enrichments Of 34s In Sulfide Minerals Of Deep-Water Marine Sediments Of The Blake Ridge, Offshore Southeastern United States, Kathryn G. Takacs, Walter S. Borowski

EKU Faculty and Staff Scholarship

Past research shows that active sulfide mineralization occurs at the base of the sulfate reduction zone (SRZ) in modern, deep-water, continental-margin sediments that overlie methane gas hydrate. These sulfide minerals (elemental sulfur, Sº; iron monosulfides, ~FeS; and pyrite, FeS2) are enriched in 34S because of sulfate reduction and anaerobic methane oxidation (AMO) processes occurring above and near the sulfate-methane interface (SMI).

The data in this study show that 5 discrete zones of sulfide minerals are preserved in a 703.8-meter sediment column associated with methane gas hydrate. These zones of sulfide minerals are also enriched in 34S. …


Geographic Information System Methodologies To Evaluate Relationships Between Land Use And Groundwater Quality In South Central Kentucky, Rhonda Pfaff Feb 2003

Geographic Information System Methodologies To Evaluate Relationships Between Land Use And Groundwater Quality In South Central Kentucky, Rhonda Pfaff

Masters Theses & Specialist Projects

The development of Geographic Information System (GIS) technology has provided techniques for a holistic approach to the study of karst groundwater contamination. While karst groundwaters supply water to a large percentage of the earth's population, its complex environments often have lacked the scientific examination and conservation measures typical of non-karst regions. In this study, GIS methodologies were explored to examine the relationships between land-use and water quality in karst watersheds. Eight watersheds throughout southern and western Kentucky were examined. The study areas included the Mammoth Cave Karst Aquifer, which is the watershed that drains the Mammoth Cave System, and seven …


Sediment Transport By Dry Ravel, Emmanuel Gabet Jan 2003

Sediment Transport By Dry Ravel, Emmanuel Gabet

Faculty Publications

Dry ravel is a general term that describes the rolling, bouncing, and sliding of individual particles down a slope and is a dominant hillslope sediment transport process in steep arid and semiarid landscapes. During fires, particles can be mobilized by the collapse of sediment wedges that have accumulated behind vegetation. On a daily basis, particles may be mobilized by bioturbation and by small landslides. Experiments on a dry ravel flume indicate that a basic expression of the momentum equation predicts the distance traveled by particles propelled down a rough surface. This equation is further elaborated to produce a nonlinear slope-dependent …


Sediment Detachment By Rain Power, Emmanuel Gabet, Thomas Dunne Jan 2003

Sediment Detachment By Rain Power, Emmanuel Gabet, Thomas Dunne

Faculty Publications

In interrill areas, overland flow is often incapable of detaching soil particles so detachment is primarily by raindrop impact. We derive a mathematical expression, rain power (R, W m−2), relating the energy expenditure of raindrops impacting a soil surface to the rate of detachment of soil particles. Rain power incorporates rainfall, hillslope, and vegetation characteristics and is modulated by flow depths. Rainfall simulation experiments on natural hillslopes were performed to measure detachment rates and across-slope flow depth distributions in surface runoff. Our results indicate that flow depths follow a Poisson distribution, and this observation is used to develop a dimensionless …


Sizes And Shapes Of 10-Ma Distal Fall Pyroclasts In The Ogallala Ggroup, Nebraska, William I. Rose, C. M. Riley, S. Dartevelle Jan 2003

Sizes And Shapes Of 10-Ma Distal Fall Pyroclasts In The Ogallala Ggroup, Nebraska, William I. Rose, C. M. Riley, S. Dartevelle

Department of Geological and Mining Engineering and Sciences Publications

Size distributions of distal ashfall particles from correlated 10-Ma layers in Nebraska, measured using laser diffraction methods, are lognormal with mode diameters of ∼90 mm. This ashfall is ∼100% bubble-wall shards of rhyolite glass and apparently represents a distal ashfall from an eruption 1400 km away. Measured terminal velocities of these ash particles are 0.2–18 cm/s, consistent with Stokes Law settling of spherical particles with diameters of 9–50 mm. Surface area of the ash particles, measured with gas adsorption, is 20–30 times the surface area of equivalent Stokes spheres. These results highlight the effects of shape and atmospheric drag in …


Quantitative Shape Measurements Of Distal Volcanic Ash, William I. Rose, Colleen M. Riley, Gregg J. Bluth Jan 2003

Quantitative Shape Measurements Of Distal Volcanic Ash, William I. Rose, Colleen M. Riley, Gregg J. Bluth

Department of Geological and Mining Engineering and Sciences Publications

Large-scale volcanic eruptions produce fine ash (< 200 μm) which has a long atmospheric residence time (1 hour or more) and can be transported great distances from the volcanic source, thus, becoming a hazard to aircraft and public health. Ash particles have irregular shapes, so data on particle shape, size, and terminal velocities are needed to understand how the irregular-shaped particles affect transport processes and radiative transfer measurements. In this study, a methodology was developed to characterize particle shapes, sizes , and terminal velocities for three ash samples of different compositions. The shape and size of 2,500 particles from 1) distal fallout (~100 km) of the October 14, 1974 Fuego eruption (basaltic), 2) the secondary maxima (~250 km) of the August 18, 1992 Spurr eruption (andesitic), and 3) the Miocene Ash Hollow member, Nebraska (rhyolitic) were measured using image analysis techniques. Samples were sorted into 10 to 19 terminal velocity groups (0.6-59.0 cm/s) using an air elutriation device. Grain size distributions for the samples were measured using laser diffraction. Aspect ratio, feret diameter, and perimeter measurements were found to be the most useful descriptors of how particle shape affects terminal velocity. These measurement values show particle shape differs greatly from a sphere (commonly used in models and algorithms). The diameters of ash particles were 10-120% larger than ideal spheres at the same terminal velocity, indicating that irregular particle shape greatly increases drag. Gas-adsorption derived surface areas are 1 to 2 orders of magnitude higher than calculated surface areas based on measured dimensions and simple geometry, indicating that particle shapes are highly irregular. Correction factors for surface area were derived from the ash sample measurements so that surface areas calculated by assuming spherical particle shapes can be corrected to reflect more realistic values.


Retrieval Of Mass And Sizes Of Particles In Sandstorms Using Two Modis Ir Bands: A Case Study Of April 7 2001 Sandstorm In China, Yingxin Gu, William I. Rose, Gregg J. Bluth Jan 2003

Retrieval Of Mass And Sizes Of Particles In Sandstorms Using Two Modis Ir Bands: A Case Study Of April 7 2001 Sandstorm In China, Yingxin Gu, William I. Rose, Gregg J. Bluth

Department of Geological and Mining Engineering and Sciences Publications

A thermal infrared remote sensing retrieval method developed by Wen and Rose [1994], which retrieves particle sizes, optical depth, and total masses of silicate particles in the volcanic cloud, was applied to an April 07, 2001 sandstorm over northern China, using MODIS. Results indicate that the area of the dust cloud observed was 1.34 million km2, the mean particle radius of the dust was 1.44 μm, and the mean optical depth at 11 μm was 0.79. The mean burden of dust was approximately 4.8 tons/km2 and the main portion of the dust storm on April 07, 2001 contained 6.5 million …


Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman Jan 2003

Preliminary Investigations Of Seasonal Changes In The Geochemical Evolution Of The Logdson River, Mammoth Cave, Kentucky, Chris Groves, Darlene M. Anthony, Joe Meiman

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Many geochemical studies have been made of karst waters worldwide. Most data that provide the framework for our current understanding of the evolution of karst waters have come from sampling at discrete times and locations, such as springs or wells. Relatively few studies have been made of the geochemical evolution of groundwater as it moves through an open flow system. This paper addresses the seasonal changes in the geochemistry of the Logsdon River conduit as it passes through nearly 10km of the carbonate aquifer of south-central Kentucky . The most important control on the ability of groundwaters to dissolve limestone …


Could Mammoth Cave Be Reduced To A Single Equation?, Chris Groves, Joe Meiman Jan 2003

Could Mammoth Cave Be Reduced To A Single Equation?, Chris Groves, Joe Meiman

Earth, Environmental, and Atmospheric Sciences Faculty Publications

Since the evolution of any cave system is largely deterministic, in theory the processes responsible for this development could be described mathematically. In a practical sense, we will never have such a model to realistically describe the evolution of the Mammoth Cave System in detail. However, the search itself can provide a framework within which to understand what processes areimportant. This can guide the design of rate process studies that would eventually be coupled to provide a comprehensive understanding of the cave's evolution. Data gaps, as well, are identified during this process. The geometry of a cave system depends on …


Red Willow County Test Hole Logs, Duane A. Eversoll Jan 2003

Red Willow County Test Hole Logs, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Mid-Holocene Climates Of The Americas: A Dynamical Response To Changed Seasonality, S. P. Harrison, J. E. Kutzbach, Z. Liu, P. J. Bartlein, B. Otto-Bliesner, Daniel R. Muhs, I. C. Prentice, R. S. Thompson Jan 2003

Mid-Holocene Climates Of The Americas: A Dynamical Response To Changed Seasonality, S. P. Harrison, J. E. Kutzbach, Z. Liu, P. J. Bartlein, B. Otto-Bliesner, Daniel R. Muhs, I. C. Prentice, R. S. Thompson

United States Geological Survey: Staff Publications

Abstract Simulations of the climatic response to mid- Holocene (6 ka BP) orbital forcing with two coupled ocean–atmosphere models (FOAM and CSM) show enhancement of monsoonal precipitation in parts of the American Southwest, Central America and northernmost South America during Northern Hemisphere summer. The enhanced onshore flow that brings precipitation into Central America is caused by a northward displacement of the inter-tropical convergence zone, driven by cooling of the equatorial and warming of the northern subtropical and mid-latitude ocean. Ocean feedbacks also enhance precipitation over the American Southwest, although the increase in monsoon precipitation there is largely driven by increases …


Strontium Isotope Geochemistry In The Central Part Of The Great Plains (Dakota) Aquifer, U.S.A.. Applied Geochemistry, D. C. Gosselin, F. E. Harvey, C. Frost, R. Stotler, P. A. Macfarlane Jan 2003

Strontium Isotope Geochemistry In The Central Part Of The Great Plains (Dakota) Aquifer, U.S.A.. Applied Geochemistry, D. C. Gosselin, F. E. Harvey, C. Frost, R. Stotler, P. A. Macfarlane

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Water Well And Spring Map Of The Hazard 30 X 60 Quadrangle, Kentucky, Bart Davidson Jan 2003

Water Well And Spring Map Of The Hazard 30 X 60 Quadrangle, Kentucky, Bart Davidson

Map and Chart--KGS

No abstract provided.


Total Thickness Of The Amburgy Coal In Eastern Kentucky, Michael G. Shultz, Jeffery A. Esterle, Ernest E. Thacker Jan 2003

Total Thickness Of The Amburgy Coal In Eastern Kentucky, Michael G. Shultz, Jeffery A. Esterle, Ernest E. Thacker

Map and Chart--KGS

This map showing the regional characteristics of the Amburgy coal bed was prepared as part of the U.S. Geological Survey's National Coal Assessment program, which compiles regional maps and databases that provide a comprehensive assessment of the most important coal beds in the nation. The Amburgy coal zone is composed of a number of distinct coal beds that merge in some areas to form mineable coal bodies. For the purpose of this assessment, the zone has been divided into two beds; the Lower Amburgy (A) and Upper Ambury (B). The lower bed is of greatest economic significance and is the …


Furnas County Test Hole Logs, Frank A. Smith Jan 2003

Furnas County Test Hole Logs, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Assessment Of Selected Reef Sites In Northern And South-Central Belize, Including Recovery From Bleaching And Hurricane Disturbances (Stony Corals, Algae And Fish), Paulette M. Peckol, H. Allen Curran, Emily Y. Floyd, Martha L. Robbart, Benjamin J. Greenstein, Kate L. Buckman Jan 2003

Assessment Of Selected Reef Sites In Northern And South-Central Belize, Including Recovery From Bleaching And Hurricane Disturbances (Stony Corals, Algae And Fish), Paulette M. Peckol, H. Allen Curran, Emily Y. Floyd, Martha L. Robbart, Benjamin J. Greenstein, Kate L. Buckman

Geosciences: Faculty Publications

The condition of coral. algal. and fish populations in fore reefs. patch reefs, and coral reef ridges was investigated at 13 sites along the northern and south-central Belize barrier reef during May 1999, documenting effects of the 1998 warming episode and Hurricane Mitch. We found high percentages of partial, or even complete, colony mortality of major reef-builders (Acropora palmata, the Montastraea annuluris species complex and Agaricia tenuifolia) that were rarely censused as recruits. A. tenuifolia, formerly a space-dominant coral in reef ridges, had incurred nearly 100% mortality after bleaching. Nearly 45% of the M. annurluris complex …


Assessment Of Coral Reefs Off San Salvador Island, Bahamas (Stony Coral, Algae And Fish Populations), Paulette M. Peckol, H. Allen Curran, Benjamin J. Greenstein, Emily Y. Floyd, Martha L. Robbart Jan 2003

Assessment Of Coral Reefs Off San Salvador Island, Bahamas (Stony Coral, Algae And Fish Populations), Paulette M. Peckol, H. Allen Curran, Benjamin J. Greenstein, Emily Y. Floyd, Martha L. Robbart

Geosciences: Faculty Publications

During assessments at 11 shallow reef sites on an Salvador Island, Bahamas in .iunc I998 we found low prevalence of disease, bleaching, and recent partial-colon1 mortality among stony corals (10 cm minimum dixncter). Old partial-colony mortalit) was >50% in Acropora palmata; however, recent tissue losses were low and it had recruits at several sites. Total (recent + old) partial-colony mortality of the Montastraea annularis species complex exceeded 30% on leeward patch reefs and back reefs. Groupers (serranids), snappers (lutjanids), and grunts (haemulids) were rare. Parrotfishes (scarids) were uncommon at most sites and surgeonfishes (acanthurids) were the dominant herbivores. Macroalgae, particularly …


Water Well And Spring Map Of The Corbin 30 X 60 Minute Quadrangle, Kentucky, Bart Davidson Jan 2003

Water Well And Spring Map Of The Corbin 30 X 60 Minute Quadrangle, Kentucky, Bart Davidson

Map and Chart--KGS

No abstract provided.


Field Trip Guide (For The Nebraska Well Drillers Association) Northeastern Nebraska Geology, S. Olafsen-Lackey, D. Eversoll Jan 2003

Field Trip Guide (For The Nebraska Well Drillers Association) Northeastern Nebraska Geology, S. Olafsen-Lackey, D. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.