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Articles 26611 - 26640 of 29957

Full-Text Articles in Geology

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer Jan 1998

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer

Journal of the Arkansas Academy of Science

Sections and subsections of the Interior Highlands of Arkansas and Oklahoma are redefined, mapped and briefly summarized. The map was produced to support the Ozark- Ouachita Highlands Assessment (OOHA), being conducted by the USDA Forest Service. It revises the USDA Forest Service map "Ecological units of the eastern United States, first approximation" by Keys et al. (1995) and the earlier maps of the natural divisions of Arkansas (Foti, 1974; Foti, 1976; Pell, 1983) to reflect new knowledge and to achieve consistency with units recognized in Missouri. Four sections (natural divisions) are defined as opposed to the three of the previous …


Factors Contributing To Landslide Activity In The Winter Of 1995-96, Clearwater County Near Orofino, Idaho, Aaron Paul Wisher Jan 1998

Factors Contributing To Landslide Activity In The Winter Of 1995-96, Clearwater County Near Orofino, Idaho, Aaron Paul Wisher

All Master's Theses

Significant landslide activity occurred in Clearwater County, Idaho in November 1995 and February-May 1996. Mass wasting in the study area consisted of debris slides and earthflows triggered by rain-on-snow weather events. It is important to determine what factors contribute to landsliding in this area so that reliable prediction can reduce the destruction of property. Through field observation and aerial photo analysis, the factors contributing to landslides were studied. The objectives included a study of the geology, soils, aspect, slope gradient, vegetation and slope position related to each slide. Also a goal was to assess the role of land use in …


Status Of Coral Reefs In The Northern Areas Of The Wider Caribbean, Judy Lang, Pedro Alcolado, Juan Pablo Carricart-Ganivet, Mark Chiappone, H. Allen Curran, Phil Dustan, Gudrun Gaudian, Francisco Geraldes, Steve Gittings, Robbie Smith, Wes Tunnell, Jean Wiener Jan 1998

Status Of Coral Reefs In The Northern Areas Of The Wider Caribbean, Judy Lang, Pedro Alcolado, Juan Pablo Carricart-Ganivet, Mark Chiappone, H. Allen Curran, Phil Dustan, Gudrun Gaudian, Francisco Geraldes, Steve Gittings, Robbie Smith, Wes Tunnell, Jean Wiener

Geosciences: Faculty Publications

Published on behalf of the (GCRMN) Global Coral Reef Monitoring Network by the Australian Institute of Marine Science


Glacial Deposits, Vol. 26, 1997-1998, Department Of Geography-Geology Jan 1998

Glacial Deposits, Vol. 26, 1997-1998, Department Of Geography-Geology

Glacial Deposits

Newsletter of the Department of Geography-Geology


Effects Of Physical And Chemical Properties Of Bright And Dull Coal Lithotypes On The Formation Of Char Particles, Chad G. Tomforde Jan 1998

Effects Of Physical And Chemical Properties Of Bright And Dull Coal Lithotypes On The Formation Of Char Particles, Chad G. Tomforde

Theses and Dissertations

The Energy and Environmental Research Center is working with EPRI and a consortium of companies in partnership with DOE to determine factors causing sticky ash to blind or bridge hot-gas cleanup filters. In this study, bright and dull lithotypes were separated from bituminous, subbituminous and lignitic coals to determine physical and chemical properties that may lead to the formation of different charforms, and consequently, fine and sticky ash that is problematic in coal-fired combustion systems.

Proximate and ultimate, maceral, and energy dispersive X-ray fluorescence (EDXRF) analyses were used to characterize each lithotype. A bench-scale pressurized fluidized-bed reactor (PFBR) was used …


Colfax County Test Hole Logs, Frank A. Smith, Raymond R. Burchett Jan 1998

Colfax County Test Hole Logs, Frank A. Smith, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Madison County Test Hole Logs, Raymond R. Burchett Jan 1998

Madison County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Washington County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1998

Washington County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Platte County Test Hole Logs, Raymond R. Burchett, Scott E. Summerside Jan 1998

Platte County Test Hole Logs, Raymond R. Burchett, Scott E. Summerside

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-Winter 1997-98 Jan 1998

Resource News-Winter 1997-98

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-Spring 1998 Jan 1998

Resource News-Spring 1998

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Earthquakes In Nebraska, R. R. Burchett Jan 1998

Earthquakes In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Oil And Gas Fields In Nebraska, R. R. Burchett Jan 1998

Oil And Gas Fields In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Mineral Facts For Nebraska, Excluding Oil And Gas, R. R. Burchett Jan 1998

Mineral Facts For Nebraska, Excluding Oil And Gas, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Continuous Lake-Sediment Records Of Glaciation In The Sierra Nevada Between 52,600 And 12,500 14c Yr B.P., Larry Benson, Howard M. May, Ronald C. Antweiler, Terry I. Brinton, Michaele Kashgarian, Joseph P. Smoot, Steve P. Lund Jan 1998

Continuous Lake-Sediment Records Of Glaciation In The Sierra Nevada Between 52,600 And 12,500 14c Yr B.P., Larry Benson, Howard M. May, Ronald C. Antweiler, Terry I. Brinton, Michaele Kashgarian, Joseph P. Smoot, Steve P. Lund

United States Geological Survey: Staff Publications

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations, Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ~24,500 and ended by ~13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO2 , MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and Si02 (amorphous) concentrations reached minimum values …


Early Life History Stages Of Gulf Sturgeon In The Suwannee River, Florida, Kenneth J. Sulak, James P. Clugston Jan 1998

Early Life History Stages Of Gulf Sturgeon In The Suwannee River, Florida, Kenneth J. Sulak, James P. Clugston

United States Geological Survey: Staff Publications

Egg sampling confirmed that Suwannee River Gulf sturgeon Acipenser ozyrinchus desotoi, a subspecies of Atlantic sturgeon A. o. oxyrinchus use the same spawning site at river kilometer (rkm) 215 from the mouth of the river each year. Forty-nine eggs were recorded in 1995, and 368 were recorded in 1996. Spawning began 4-7 d after the March new moon in both years and lasted 10-11 d; in 1996, a second 10-d spawning round began on the April new moon. Developmental synchrony among eggs recovered suggested serval discrete spawning events in both years. Total eggs deposited for three 1996 sampling days …


The Cave Exploration Group Of East Africa And Volcanic Caves In Kenya, Michael Declan Kennedy Jan 1998

The Cave Exploration Group Of East Africa And Volcanic Caves In Kenya, Michael Declan Kennedy

International Journal of Speleology

This paper looks at the history of the Cave Exploration Group of East Africa with special reference to the exploration of volcanic caves. It demonstrates that the group has concentrated on two main areas, the Chyulu HiIls and Mt. Suswa, although other areas have also been studied. The Cave Exploration Group of East Africa has had to cope with various problems. The most important of which are related to the socio-economic conditions of a developing country. These problems have not prevented the group from making a valuable contribution to vulcanospeleology.


Determining Capture Zones For Three-Dimensional, Heterogeneous, Anisotropic Aquifers By Monte Carlo Analysis, Jon Paul Jones Jan 1998

Determining Capture Zones For Three-Dimensional, Heterogeneous, Anisotropic Aquifers By Monte Carlo Analysis, Jon Paul Jones

Theses and Dissertations

Most methods of delineating capture zones for pump-and-treat remedial design and wellhead protection assume a two-dimensional, homogeneous aquifer. Aquifers, however, are three-dimensional and heterogeneous, thereby introducing uncertainty in capture zone analysis. This study used a Monte Carlo analysis of three sets of statistical parameters defining aquifer heterogeneity. Each set had a different variance for the mean natural log hydraulic conductivity, which varied among the sets by a factor of four. The ensemble means of the capture zones for each set were estimated from 10 randomly generated fields with 12 layers each which were superimposed on each other for a total …


Effective Elastic Thickness Of The Lithosphere Along The Easter Seamount Chain, Sarah E. Kruse, Zhengro J. Liu, David F. Naar, Robert A. Duncan Dec 1997

Effective Elastic Thickness Of The Lithosphere Along The Easter Seamount Chain, Sarah E. Kruse, Zhengro J. Liu, David F. Naar, Robert A. Duncan

Geology Faculty Publications

Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent results. With the exception of the eastern and western ends of the ESC the effective elastic thickness along the chain is ∼1–4 km. The thin elastic thickness for the majority of the ESC seamounts is compatible with a young seafloor age at the time of loading derived from new radiometric …


Lithologic And Stratigraphic Analysis Of Glacial Diamictons, Sturgis, Michigan, R. Christopher Gardner Dec 1997

Lithologic And Stratigraphic Analysis Of Glacial Diamictons, Sturgis, Michigan, R. Christopher Gardner

Masters Theses

Seven diamictons are identified in the subsurface glacial drift near Sturgis, Michigan using textural analyses and x-ray diffraction of clay minerals. The clay mineral content is quantified by comparing the 7-A/10- A peak height ratios from x-ray diffraction diffractograms of oriented clay-size particle (< 2um) mounts. Two diamictons occur at the base of the drift. Unit 1 is gray , resembling the shale it overlies. The texture of Unit 1 is sandy clay loam to loam and average 7-A/10-A peak height clay mineral ratios of 0.446 ±0.069. Unit 2 is a yellowish-brown diamicton, it overlies Unit 1, and is a sandy loam to loam with average 7-A/10-A clay mineral ratio of 0.657 ±0.151. Diamicton Units 4 and 5 overlie a thick unit of sand and gravel on top of Unit 2. Units 4 and 5 have similar color and texture, however the 7-A/10-A ratios are 1.059 ±0.090 and 0.810 ±0.072 respectively. Unit 6 is a thin diamicton unit, leached of calcite, and x-ray diffraction suggests that there is a range of weathering horzins between borings. Unit 7 is loamy, whereas Unit 8 generally ranges from sandy clay loam to sandy loam with average 7-A/10-A ratios of 0.865 ±0.090 and 1.195 ±0.189.


A Comparison Study Of Water Well Grouting Materials, Sherry L. Callaway Dec 1997

A Comparison Study Of Water Well Grouting Materials, Sherry L. Callaway

Masters Theses

To prevent contamination from occurring in water wells, and thereby groundwater, the annulus between the well casing and borehole wall must be sealed with a grout that is capable of maintaining a proper seal. Several factors and properties determine the integrity of the grout and the seal formed by that grout.

A field study discovered limitations in all of the tested grout types. Most grouts were found to vary greatly in thickness surrounding the well casing. Bentonite slurry grouts settled excessively. Cement and bentoni tecement grouts did not adhere to PVC well casing. Bentonite-cement grout fractured. The granulated bentonite was …


Laboratory Comparison Of Trench Design Options For Recovering Spilled Oil, Renuka Fernando Dec 1997

Laboratory Comparison Of Trench Design Options For Recovering Spilled Oil, Renuka Fernando

Masters Theses

The research goal was to improve the performance of drainage trenches used to recover spilled oil in the subsurface. Different trench designs were compared in two laboratory experiments. The first laboratory experiment clearly demonstrates that the performance of a oil recovering drainage trench could be improved by replacing the standard gravel pack sand used around the drain pipe with mixtures of teflon and sand. The effectiveness of a downgradient impermeable 'backstop' also was studied in the first experiment.

In experiment two, four trench designs were compared: perforated drain pipe; wire-wrapped horizontal well screen; perforated sheet pile; and gravel fill with …


Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson Dec 1997

Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali basalts on Citadel Mountain form the southern margin of the Lunar Crater Volcanic Field (LCVF) in the central Great Basin, Nevada. Citadel Mountain comprised of a faulted, north tilted section of Tertiary andesite and ash-flow tuff is capped by Pliocene and Quaternary alkali basalt flows that erupted from six major cinder cones. The basalt flows on Citadel Mountain can be divided into two groups (older and younger) based on age and isotopic signatures. The older basalt group is characterized by higher 87 Sr/86Sr and lower ENd and the younger group has lower 87Sr/86Sr …


Vertical Axis Rotation In The Silurian Hills: A Cenozoic Overprint On The Mesozoic U.S. Cordilleran Magmatic Arc, John E. Comstock Dec 1997

Vertical Axis Rotation In The Silurian Hills: A Cenozoic Overprint On The Mesozoic U.S. Cordilleran Magmatic Arc, John E. Comstock

LSU New Orleans Theses and Dissertations

New, detailed field work in the Silurian hills, southeast of Death Valley, reveals a pattern of a complex Cenozoic brittle fault overprint of rocks containing evidence of at least three episodes of Mesozoic thermal-ductile deformation. The Cenozoic brittle fault overprint of rocks containing evidence of at least three episodes of Mesozoic thermal-ductile formation. The Cenozoic faulting consists of five distinct sets of structures ordered by cross cutting relationships. The oldest, BF1, are fragments of reverse faults trending NW and dipping 45-60 SW. BF2 consist of NW trending, en echelon, sinistral strike-slip faults. BF3 is a conjugate set of N-NE trending …


The Migration Of Arsenic And Lead In Surface Sediments At Three Kids Mine Henderson, Nevada, Douglas Brian Sims Dec 1997

The Migration Of Arsenic And Lead In Surface Sediments At Three Kids Mine Henderson, Nevada, Douglas Brian Sims

Publications (WR)

This study focused on the distribution of arsenic and lead in surface sediments at Three Kids Mine in Henderson, Nevada. The mine site encompasses approximately 470 acres of desert and is situated above two developing communities (Lake Las Vegas and Calico Ridge) and the Las Vegas Valley's water source (Lake Mead). Transport of arsenic and lead appears to have occurred within a limited range in both the eastern and western washes on the eastern and western sides of Three Kids Mine. Concentrations of arsenic range between 20 mg/kg (ppm) and 1130 mg/kg and between 20 mg/kg and 8400 mg/kg for …


Geology Newsletter- 1997, Department Of Geology Nov 1997

Geology Newsletter- 1997, Department Of Geology

Geological and Environmental Sciences News

Vol. 1, No. 22

  • Dear Alumni and Friends
  • Faculty News
  • Awards and Scholarships
  • Alumni News
  • Geology Development and Scholarship Donations
  • Advisory Council News


Salinity And Hydrology Of The Mills Lake Catchment, R Ferdowsian, A T. Ryder Nov 1997

Salinity And Hydrology Of The Mills Lake Catchment, R Ferdowsian, A T. Ryder

Resource management technical reports

The Mills Lake Catchment is located north of the Ongerup-Jerramungup Road, 35 km west of Jerramungup and 10 km north-east of Ongerup. It covers about 23,800 ha of agricultural land that is more than 90% cleared and predominantly cropped. The average annual rainfall of the catchment is about 370 mm. Many low-lying parts of the study area have become salt-affected during recent years. The extent of soil salinity is growing rapidly and it is feared that, without any treatment, more land will become salt-affected.


Stratospheric Loading Of Sulfur From Explosive Volcanic Eruptions, Gregg J. Bluth, William I. Rose, Ian E. Sprod, Arlin J. Krueger Nov 1997

Stratospheric Loading Of Sulfur From Explosive Volcanic Eruptions, Gregg J. Bluth, William I. Rose, Ian E. Sprod, Arlin J. Krueger

Department of Geological and Mining Engineering and Sciences Publications

This paper is an attempt to measure our understanding of volcano/atmosphere interactions by comparing a box model of potential volcanogenic aerosol production and removal in the stratosphere with the stratospheric aerosol optical depth over the period of 1979 to 1994. Model results and observed data are in good agreement both in magnitude and removal rates for the two largest eruptions, El Chicho´n and Pinatubo. However, the peak of stratospheric optical depth occurs about nine months after the eruptions, four times longer than the model prediction, which is driven by actual SO2 measurements. For smaller eruptions, the observed stratospheric perturbation is …


S K S Splitting Beneath Continental Rift Zones, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Andrew W. Rigor, Yu A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov, Nikolai A. Logatchev Oct 1997

S K S Splitting Beneath Continental Rift Zones, Stephen S. Gao, Paul M. Davis, Kelly H. Liu, Philip D. Slack, Andrew W. Rigor, Yu A. Zorin, Valentina V. Mordvinova, Vladimir M. Kozhevnikov, Nikolai A. Logatchev

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We present measurements of S K S splitting at 28 digital seismic stations and 35 analog stations in the Baikal rift zone, Siberia, and adjacent areas, and at 17 stations in the East African Rift in Kenya and compare them with previous measurements from the Rio Grande Rift of North America. Fast directions in the inner region of the Baikal rift zone are distributed in two orthogonal directions, NE and NW, approximately parallel and perpendicular to the NE strike of the rift. In the adjacent Siberian platform and northern Mongolian fold belt, only the rift-orthogonal fast direction is observed. In …


An Ice Shelf Mechanism For Heinrich Layer Production, Christina L. Hulbe Oct 1997

An Ice Shelf Mechanism For Heinrich Layer Production, Christina L. Hulbe

Geology Faculty Publications and Presentations

The effect of an ice shelf in the Labrador Sea on ice-rafted sediment delivery to the glacial North Atlantic is investigated using a finite element numerical model of ice shelf flow. Discharge into the shelf from Hudson Strait creates a thick central core, extending downstream into the shelf, that is flanked by relatively thin ice. Melting at the base of the deep keel would produce cool, fresh water which would rise to refreeze along the keel's flanks. Debris deposited by melting deep central ice could create the Heinrich layers observed in the Labrador Sea while the debris-rich ice protected by …