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Articles 26941 - 26970 of 29958

Full-Text Articles in Geology

Geochemical Evidence Of Saharan Dust Parent Material For Soils Developed On Quaternary Limestones Of Caribbean And Western Atlantic Islands, Daniel R. Muhs, Charles A. Bush, Kathleen C. Stewart, Tracy R. Rowland, Russell C. Crittenden Jan 1994

Geochemical Evidence Of Saharan Dust Parent Material For Soils Developed On Quaternary Limestones Of Caribbean And Western Atlantic Islands, Daniel R. Muhs, Charles A. Bush, Kathleen C. Stewart, Tracy R. Rowland, Russell C. Crittenden

United States Geological Survey: Staff Publications

Most previous workers have regarded the insoluble residues of high-purity Quatemary limestones (coral reefs and oolites) as the most important parent material for well-developed, clay-rich soils on Caribbean and western Atlantic islands, but this genetic mechanism requires unreasonable amounts of limestone solution in Quatemary time. Other possible parent materials from external sources are volcanic ash from the Lesser Antilles island arc and Saharan dust carried across the Atlantic Ocean on the northeast trade winds. Soils on Quatemary coral terraces and carbonate eolianites on Barbados, Jamaica, the Florida Keys (United States), and New Providence Island (Bahamas) were studied to determine which, …


Fossil Charcoal In Cretaceous-Tertiary Boundary Strata: Evidence For Catastrophic Firestorm And Megawave, Michael A. Kruge Jan 1994

Fossil Charcoal In Cretaceous-Tertiary Boundary Strata: Evidence For Catastrophic Firestorm And Megawave, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Organic matter separated from calcareous sandstone from the upper portion of a deep-water tsunami deposit at Arroyo el Mimbral, Taumalipas (Mexico), which marks the biostratigraphically-defined Cretaceous-Tertiary boundary, consists primarily of fossil charcoal, including semifusinite and pyrofusinite. Analytical pyrolysis-gas chromatography-mass spectrometry revealed the highly aromatic and polyaromatic character of the organic matter assemblage, typical of the products of partial combustion. The organic matter probably originated as terrestrial vegetation that was caught in a firestorm and subsequently transported far offshore in the backwash of a megawave. These data are consistent with the hypothesis of combustion of large masses of vegetation triggered by …


Sand And Gravel Resources Along The Ohio River Valley In Boone, Gallatin, And Carroll Counties, Kentucky, Eugene J. Amaral Jan 1994

Sand And Gravel Resources Along The Ohio River Valley In Boone, Gallatin, And Carroll Counties, Kentucky, Eugene J. Amaral

Report of Investigations--KGS

Glacial outwash sand and gravel from three northern Kentucky counties in the Ohio River Valley have been analyzed in order to characterize their particle size, composition, morphology, and surface alteration and to determine the geologic significance of lateral and stratigraphic variations in these sediment properties. The late Wisconsinan-age deposits, actively mined in terraces along the Ohio River, are composed of moderately sorted sand and a poorly sorted, bimodal mixture of sand and gravel. A systematic pattern of regional grain-size variation was found to be associated with the confluence of the Great Miami River, a major meltwater sluiceway entering the Ohio …


A Method For Determining Ice-Thickness Change At Remote Locations Using Gps, Christina L. Hulbe, I. M. Whillans Jan 1994

A Method For Determining Ice-Thickness Change At Remote Locations Using Gps, Christina L. Hulbe, I. M. Whillans

Geology Faculty Publications and Presentations

Ice-thickness changes at remote locations on ice sheets can be determined by means of precise Global Positioning System (GPS) surveys with interferometric solutions. Remote sites are precisely surveyed relative to GPS receivers on rock. Repeat observations of the position of a remote site provide its vertical velocity. The difference between this velocity and accumulation rate is an indicator of change in ice-sheet thickness. Allowance must be made for the movement of survey markers due to firn compaction and down-slope ice motion, To allow for firn compaction, very long- poles arc placed to a sufficient depth in the firn that the …


Directory Of Nebraska Quarries, Pits, And Mines, R. R. Burchett Jan 1994

Directory Of Nebraska Quarries, Pits, And Mines, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource Notes-Academic Year 1993-94 Jan 1994

Resource Notes-Academic Year 1993-94

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Storm Dominated Channel Sequences On A Shallow Marine Shelf: Morrowan Of Northwest Arkansas, Kimberley R. Jones, Doy L. Zachry Jan 1994

Storm Dominated Channel Sequences On A Shallow Marine Shelf: Morrowan Of Northwest Arkansas, Kimberley R. Jones, Doy L. Zachry

Journal of the Arkansas Academy of Science

The Brentwood Member of the Bloyd Formation (Morrowan, Pennsylvanian) in northwestern Arkansas contains stratigraphic sequences deposted by tropical storms in middle shelf environments. The deposits are confined to shallow channels incised by strong unidirectional currents into an interval of shale deposited during fair weather conditions. Complete storm sequences reflect initial bottom currents of high competency that declined through time and were succeeded by wave generated oscillatory activity. The storm succession consists of an erosion surface followed by a basal pebble conglomerate, massive grainstone and packstone, whole-fossil wackestone, hummocky cross-strata and a swell lag of platy crinoidcalyxes. As storm activity ceased, …


Impact Of Riparian Grass Filter Strips On Surface-Water Quality, Alex W. Fogle, Daniel I. Carey, Billy J. Barfield, Robert L. Blevins, Vasilios P. Evangelou, Cora E. Madison, Shreeram P. Inamdar Jan 1994

Impact Of Riparian Grass Filter Strips On Surface-Water Quality, Alex W. Fogle, Daniel I. Carey, Billy J. Barfield, Robert L. Blevins, Vasilios P. Evangelou, Cora E. Madison, Shreeram P. Inamdar

Information Circular--KGS

The effectiveness of natural riparian grass filter strips in removing sediment and agricultural chemicals from surface runoff was studied using no-tillage and conventional-tillage erosion plots. Runoff from the tillage plots was directed onto 4.57, 9.14, and 13.72 m (15, 30, and 45 ft.) length filter strips, where the inflow and outflow concentrations and sediment size distributions were measured. Trapping efficiencies for sediment and agricultural chemicals typically ranged near or above 90 percent, mainly because of high infiltration rates. The filters also significantly reduced peak discharge concentrations, which reduced the impact of sediment and agricultural chemicals on receiving surface waters.


Available Coal Resources Of The Salyersville South 7.5-Minute Quadrangle, Magoffin County, Kentucky, Robert E. Andrews, Gerald A. Weisenfluh, John K. Hiett, Richard E. Sergeant Jan 1994

Available Coal Resources Of The Salyersville South 7.5-Minute Quadrangle, Magoffin County, Kentucky, Robert E. Andrews, Gerald A. Weisenfluh, John K. Hiett, Richard E. Sergeant

Information Circular--KGS

Coal resources available for mining have been estimated for the Salyersville South Quadrangle, which is located in the Licking River Coal Reserve District of the Eastern Kentucky Coal Field. Nine coal beds within the quadrangle are potentially mineable and constitute the basis of these resource estimates. Seven of these beds have been commercially developed, but only five have produced more than 1 million tons: from youngest to oldest, the Skyline A, Lower Broas, Lower Peach Orchard, Middle Peach Orchard, and Upper Peach Orchard. A computerized Geographic Information System was used to calculate estimates of original, mined-out, and remaining resources, as …


Limestone And Lime For So2 And Pollutant Control In The Ohio Valley, James C. Cobb, Garland R. Dever Jr. Jan 1994

Limestone And Lime For So2 And Pollutant Control In The Ohio Valley, James C. Cobb, Garland R. Dever Jr.

Information Circular--KGS

The purpose of this conference is to emphasize the importance of limestone resources for controlling SO2 emissions from coal-fired power plants. We have brought together experts from utilities to describe important factors in limestone performance in scrubbers and from the stone industry to describe important factors in limestone and lime production. Conference speakers include also representatives from research institutes, equipment manufacturers, government agencies, and geological surveys.


Chemical And Statistical Analysis Of A Sampled Interval In The Camp Nelson Limestone (Upper Ordovician) Madison County, Central Kentucky, Garland R. Dever Jr., Warren H. Anderson, Henry E. Francis, O. Barton Davidson, Mark F. Thompson Jan 1994

Chemical And Statistical Analysis Of A Sampled Interval In The Camp Nelson Limestone (Upper Ordovician) Madison County, Central Kentucky, Garland R. Dever Jr., Warren H. Anderson, Henry E. Francis, O. Barton Davidson, Mark F. Thompson

Information Circular--KGS

The Camp Nelson Limestone of the High Bridge Group (Upper Ordovician) is mined at seven sites in central and north-central Kentucky for industrial, construction, and agricultural uses. As part of a regional investigation of its chemical characteristics, a 67-foot section in the upper Camp Nelson, which is being mined at Boonesborough, Madison County, was sampled for major-element analysis.

The upper Camp Nelson in the Boonesborough Mine consists of two zones (23 and 30 feet thick) of low-silica stone (4 percent or less total SiO2) separated by a 14-foot section of slightly argillaceous limestone with an average silica content …


Evaluation Of A Possible Subsurface Impact Crater: The Newporte Structure, Northwestern Renville County, North Dakota, Timothy R. Gerlach Jan 1994

Evaluation Of A Possible Subsurface Impact Crater: The Newporte Structure, Northwestern Renville County, North Dakota, Timothy R. Gerlach

Theses and Dissertations

The purpose of this study was to determine if enough evidence exists to support an impact origin hypothesis the Newporte structure. Newporte, a petroliferous, subsurface, crater-shaped feature is located one mile south of the North Dakota - Saskatchewan border in Renville County. It is evident in Precambrian through Ordovician strata at depths of 9100 to 9600 ft (2774 to 2926 m) structure is approximately 2.0 miles (J.2 km) in diameter. Shell Oil company discovered Newporte field when testing this seismically-defined structure in 1977.

Seismic reflection profiling data and synthetic seismograms were used to generate maps that confirmed the circularity of …


A Comparison Of Wellhead Protection Area Delineation Methods At Larimore, North Dakota, Barbara L. Sahl Jan 1994

A Comparison Of Wellhead Protection Area Delineation Methods At Larimore, North Dakota, Barbara L. Sahl

Theses and Dissertations

Many communities in North Dakota rely on water from shallow, unconfined aquifers that are vulnerable to contamination. A strategy to protect public groundwater supplies is the delineation of wellhead protection areas (WHPAs) around the area which contributes water to a well. Several delineation methods are available, all of which have simplifying assumptions which affect the size or shape of a predicted WHPA.

Five WHPA delineation methods were compared to determine which simplified the aquifer/well system while preserving essential hydrogeologic features. A simple system may not require a complex model to predict an accurate WHPA. Sensitivity of each to changes in …


Preferential Flow Mechanisms : Their Interaction And Effect On Dye Movement In Till And Glaciolacustrine Sediment, Calvin D. Taylor Jan 1994

Preferential Flow Mechanisms : Their Interaction And Effect On Dye Movement In Till And Glaciolacustrine Sediment, Calvin D. Taylor

Theses and Dissertations

Contamination of groundwater by agricultural chemicals is of concern to the population of the Northern Great Plains. Preferential flow (macropore, finger, and funnel) allows such chemicals to move relatively rapidly through materials considered to be aquitards. Preferential flow mechanisms at two sites in North Dakota, one in till, the other in glaciolacustrine sediments were determined by application of blue dye (FD&C No 1) solution to framed sites (9m2 & 4m2) with the topsoil removed. The sites were then cored and blocks hand-excavated to depths of 1.5 and 2.5-meters. The three types of preferential flow (macropore, finger, and funnel) were analyzed …


The Champlain Thrust System In Northwestern Vermont - Structure And Lithology Of The Taconic Foreland Sequence In The Highgate Center Quadrangle, Michael Roger Haschke Jan 1994

The Champlain Thrust System In Northwestern Vermont - Structure And Lithology Of The Taconic Foreland Sequence In The Highgate Center Quadrangle, Michael Roger Haschke

Geology Theses and Dissertations

The Champlain Thrust System, responsible for the final emplacement of the Taconic Allochthon, and which represents the surface trace of the main detachment under the Taconic suite, can be traced throughout the study area in northwestern Vermont, northward into southern Quebec. In the Highgate and St. Albans area this imbricated assemblage consists of 3 main carbonate thrust slices (Highgate Springs-, Philipsburg-, Rosenberg slice), each of which contain rocks deposited during some part of early Cambrian to medial Ordovician time. The Highgate Springs sequence comprises a mildly deformed early to medial Ordovician carbonate-shale succession. Late Cambrian to early Ordovician carbonates of …


Structure And Tectonic Significance Of Deformed Medial Ordovician Flysch And Melange Between Albany And Saratoga Lake And In The Central Hudson Valley, New York, Andreas Plesch Jan 1994

Structure And Tectonic Significance Of Deformed Medial Ordovician Flysch And Melange Between Albany And Saratoga Lake And In The Central Hudson Valley, New York, Andreas Plesch

Geology Theses and Dissertations

The belt of medial Ordovician deformed flysch west of the traditionally defined Taconic boundary thrust was investigated by detailed mapping in the Capital District, from Albany to Saratoga Lake, and large scale compilation of the central Hudson Valley, between Glens Falls and Middletown. Maps and detailed sections are presented. Mapping recognized a two-fold division into a western belt of folded and faulted flysch and an eastern belt which is dominated by tectonic melange. The Folded and Faulted Flysch unit shows northward fining from greywacke-dominated to shale-dominated. Isoclinal folding and incipient melanges are characteristic in the south, whereas in the north …


Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson Jan 1994

Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson

United States Geological Survey: Staff Publications

A physically based model of variations in δ18O and δ2H in Pyramid Lake is presented. For inputs, the model uses measurements of liquid water inflows and outflows and their associated isotopic compositions and a set of meteorological data (radiative fluxes, air temperature, relative humidity, and windspced). The model simulates change of lake volume, thermal and isotopic stratification, evaporation, and the isotopic composition of evaporation. A validation of the model for 1987-1989 and 1991 indicates that it can reproduce measured intra- and interannual variations of δ18O and δ2H. Three applications of the model …


Rocks And Minerals Of Kentucky, Warren H. Anderson Jan 1994

Rocks And Minerals Of Kentucky, Warren H. Anderson

Special Publication--KGS

This publication gives information about rocks and minerals of Kentucky and is organized to (1) help in your identification and study of Kentucky rocks and minerals, (2) explain how rocks and minerals are formed and why they are important to the Commonwealth, and (3) be a simplified reference.


Ground Water In The Kentucky River Basin, Daniel I. Carey, James C. Currens, James S. Dinger, James A. Kipp, David R. Wunsch, Philip G. Conrad Jan 1994

Ground Water In The Kentucky River Basin, Daniel I. Carey, James C. Currens, James S. Dinger, James A. Kipp, David R. Wunsch, Philip G. Conrad

Information Circular--KGS

Most private wells in the Kentucky River Basin are in unconfined or semi-confined bedrock aquifers. Within these aquifers, high-yield zones are irregularly distributed. The most productive wells are drilled into fractured bedrock and alluvium along the Kentucky River floodplain. The data indicate that ground water acts as a buffer to peak and low flows in Kentucky River Basin streams. At current withdrawal rates, ground-water usage does not seem to have an adverse impact on the Kentucky River. Privately owned ground-water sources supply approximately 135,000 people living in the basin-approximately 19 percent of the total population and 36 percent of the …


Quaternary Seismic Stratigraphy Of The Inner Shelf And Coastal Zone, Southern Delmarva Peninsula, Virginia, Anthony M. Foyle Jan 1994

Quaternary Seismic Stratigraphy Of The Inner Shelf And Coastal Zone, Southern Delmarva Peninsula, Virginia, Anthony M. Foyle

OES Theses and Dissertations

The Pleistocene stratigraphic record beneath the Virginia inner shelf is largely unknown. On the adjacent lower Atlantic Coastal Plain of southeastern Virginia, the Pleistocene record consists of seven stacked transgressive sequences, while on the southern Delmarva Peninsula, a series of three transgressive to highstand sequences are developed. Reconstruction of the mid-Atlantic basin margin response to high-frequency Quaternary glacioeustasy is limited by this sparse record of late transgressive through early regressive deposition. Knowledge of high-frequency depositional sequence architecture, developed under conditions of low subsidence (to net uplift) and low sediment input, is also incomplete. The Atlantic inner shelf and coastal zone, …


The Dinoflagellate Flora Of The Late Oligocene - Early Miocene Old Church Formation Mid-Atlantic Coastal Plain, Alan P. Hoffmeister Jan 1994

The Dinoflagellate Flora Of The Late Oligocene - Early Miocene Old Church Formation Mid-Atlantic Coastal Plain, Alan P. Hoffmeister

OES Theses and Dissertations

The Old Church Formation contains the only presently known exposed Oligocene sediments in the North American mid-Atlantic Coastal Plain. Some ambiguity concerning the exact age of the Old Church Formation exists because it may include both Oligocene and Miocene sediments. Two outcrops and four cores containing the Old Church Formation were examined for dinoflagellates to determine the composition of the dinoflagellate flora in the Old Church Formation, the age of the Old Church Formation as indicated by this flora, general depositional environment of the Old Church Formation and correlative relationships of the Old Church Formation with other Coastal Plain units. …


Groundwater-Level Changes In Nebraska, 1992, Gregory V. Steele, Perry B. Wigley Jan 1994

Groundwater-Level Changes In Nebraska, 1992, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Location Of Registered Irrigation Wells In Nebraska As Of 1994 Jan 1994

Location Of Registered Irrigation Wells In Nebraska As Of 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-Spring 1994 Jan 1994

Resource News-Spring 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-Summer 1994 Jan 1994

Resource News-Summer 1994

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Mineral Operations Review, 1993, Raymond R. Burchett, Duane A. Eversoll Jan 1994

Nebraska Mineral Operations Review, 1993, Raymond R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Source Rock Geochemistry Of The Southern Tyee Basin, Southwest Oregon, David E. Long Jan 1994

Source Rock Geochemistry Of The Southern Tyee Basin, Southwest Oregon, David E. Long

Dissertations and Theses

This study examined source rock geochemistry of the southern Tyee Basin. Total organic carbon, rock-eval pyrolysis, vitrinite reflectance, thermal alteration index and visual assessments were performed on splits from cutting samples from five wells and on outcrop samples from four measured sections. Organic matter was found to be dispersed, averaging about 0.5 weight percent. The organic matter is primarily terrestrial in origin, or type I l l , with low potential for gas production and no oil potential. Three coal samples are clearly the richest sources of organic matter examined in this study.


Isostatic Rebound In The Lake Agassiz Basin Since The Late Wisconsinan, Eric C. Brevik Jan 1994

Isostatic Rebound In The Lake Agassiz Basin Since The Late Wisconsinan, Eric C. Brevik

Theses and Dissertations

This study addressed three main questions: I) how thick was the ice that covered the southern Lake Agassiz basin during the Wisconsinan and how much that ice depressed the crust, 2) how much rebound has occurred since deglaciation and whether or not rebound is complete, and 3) what were the effects of this rebound on the basin.

The most direct method of measuring rebound in the Lake Agassiz basin is from strandlines left by glacial Lake Agassiz. The oldest complete strandline, the Herman, presumably rebounded, with the northern end rebounding more because the ice was thicker there and had melted …


A High Resolution Gravity Survey For The Detection Of Pleistocene Aquifers Underlying The Fort Berthold Indian Reservation, North Dakota, Mark R. Mcdonald Jan 1994

A High Resolution Gravity Survey For The Detection Of Pleistocene Aquifers Underlying The Fort Berthold Indian Reservation, North Dakota, Mark R. Mcdonald

Theses and Dissertations

A high resolution gravity survey was performed over portions of McLean, Mountrail, and Ward Counties in central North Dakota during the fall and winter of 1990-1991. The study was performed to locate and map Pleistocene sand and gravel aquifers. Well data indicate that aquifers beneath the study area range in thickness from 1 to 60 meters. The Bouguer gravity anomalies resulting from these shallow aquifers was estimated to be on the order of 1 to 2 mgals. Previous studies have focused on available well data and by mapping topographic lows. Due to the inferential nature of these studies, the detailed …


Evaluation Of Strain Rates On Ice Stream B, Antarctica, Obtained Using Differential Gps, Christina L. Hulbe, I. M. Whillans Jan 1994

Evaluation Of Strain Rates On Ice Stream B, Antarctica, Obtained Using Differential Gps, Christina L. Hulbe, I. M. Whillans

Geology Faculty Publications and Presentations

The "stop-and-go" kinematic Global Positioning System (CPS) technique was used to survey 270 stations twice within a 25 km by 10 km strain grid on the surface of Ice Stream B. One or two geodetic quality receivers operated as reference pivots, while two similar receivers traveled to grid stations. Each station was occupied for 25 s. The method is rapid and reliable. Each survey was completed within 2 weeks. Calculated horizontal strain rates are accurate to 1%. Relative vertical velocities are accurate to 20 mm kmI a-1. Maps of the four horizontal velocity gradients, relative vertical velocity and surface elevation …