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Articles 811 - 822 of 822

Full-Text Articles in Other Earth Sciences

Changing Fields: Agricultural Land Use Changes In Nebraska 1925-1974, Donald A. Wilhite Apr 1979

Changing Fields: Agricultural Land Use Changes In Nebraska 1925-1974, Donald A. Wilhite

National Drought Mitigation Center: Faculty Publications

The series of graphs and maps which follow illustrate agricultural land use changes in Nebraska from 1925 to 1974. With these graphs and maps, the major agronomic crops of corn (dryland and irrigated), wheat, sorghum and soybeans are analyzed. The purpose of this analysis is to provide a pictorial history of Nebraska's ever-changing cropping system and, hopefully, to stimulate ideas and discussion with regard to trends and future directions. The Nebraska Water Resources Center is deeply interested in both the past and the future of Nebraska's agriculture because of the demands which agriculture places on the state's water resources. An …


Turbulence Spectra Above A Vegetated Surface Under Conditions Of Sensible Heat Advection, Raymond P. Motha, Shashi B. Verma, Norman J. Rosenberg Jan 1979

Turbulence Spectra Above A Vegetated Surface Under Conditions Of Sensible Heat Advection, Raymond P. Motha, Shashi B. Verma, Norman J. Rosenberg

National Drought Mitigation Center: Faculty Publications

Spectra of vertical and horizontal velocity, air temperature and humidity fluctuations were analyzed from measurements made over a well-watered alfalfa crop under conditions of sensible heat advection. Vertical velocity and air temperature spectra as well as cospectra of momentum, sensible heat and water vapor were found to be dependent on atmospheric thermal stratification. These spectra and cospectra were shifted toward higher frequencies under advective as compared to lapse conditions. These results indicate that the predominant eddy sizes are relatively smaller under advective conditions. Humidity spectra, on the other hand, were independent of daytime thermal stratification conditions but were influenced by …


Uranium Transport In The Walker River Basin, California And Nevada, Larry Benson, D. L. Leach Jan 1979

Uranium Transport In The Walker River Basin, California And Nevada, Larry Benson, D. L. Leach

United States Geological Survey: Staff Publications

During the summer of 1976 waters from tributaries, rivers, springs and wells were sampled in the Walker River Basin. Snow and sediments from selected sites were also sampled. All samples were analyzed for uranium and other elements. The resulting data provide an understanding of the transport of uranium within a closed hydrologic basin as well as providing a basis for the design of geochemical reconnaissance studies for the Basin and Range Province of the Western United States. Spring and tributary data are useful in locating areas containing anomalous concentrations of uranium. However, agricultural practices obscure the presence of known uranium …


Extreme Evapotranspiration By Irrigated Alfalfa: A Consequence Of The 1976 Midwestern Drought, Norman J. Rosenberg, Shashi B. Verma Feb 1978

Extreme Evapotranspiration By Irrigated Alfalfa: A Consequence Of The 1976 Midwestern Drought, Norman J. Rosenberg, Shashi B. Verma

National Drought Mitigation Center: Faculty Publications

The rate of evapotranspiration by irrigated alfalfa at Mead, NE (41°09'Nj 96°30'W, elevation 354 m) reached record levels in 1976. Evapotranspiration was measured with precision weighing lysimeters in a field 1.9 ha in size. Evapotranspiration ranged during the growing season from 4.75 to 14.22 mm day-l and exceeded 10 mm day-I on one-third of the days studied. On each day of study the ratio of latent heat flux density (LE) to the sum of the net radiation and soil heat flux densities (Rn+S) was such that LE/ (Rn+S) > 1, indicating the occurrence of significant …


Coumbe Bluff Quadrangle, Garden County, Nebraska, Robert F. Diffendal Jr. Aug 1977

Coumbe Bluff Quadrangle, Garden County, Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

7.5' topgraphic quadrangle showing exposures of bedrock formations and other geologic information.

41° 22'30" — 41° 30'

102° 22'30" — 102° 30'

Scale 1:24,000

High resolution .tif file attached below as supplemental file


Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson Jan 1973

Regional Hydrothermal Alteration Of The Leadville Limestone (Mississippian) Of Central Colorado, L. V. Benson

United States Geological Survey: Staff Publications

Massive metallic-sulfide deposits were implaced in the Leadville Limestone {Mississippian) of Central Colorado less than 70 million years ago. The thermal fluids which precipitated ore at Gilman, Colorado have regionally altered the Leadville Limestone. The sequence of alteration began with the recrystallization of limestone to a dark medium~grained dolomite containing a homogeneous distribution of Fe. This Was followed by partial recrystallization of the medium-grained dolomite to coarse-clear dolomite which contains an inhomogeneous distribution of Fe. The resulting banded rock is known as "zebra rock" . Precipitation of Si0 2 (jasperoid) occurred next. The jaspe=oid formed prior to the deposition of …


Paleotectonic Investigations Of The Permian System In The United States, Edwin D. Mckee, Stephen S. Oriel, Henry L. Berryhill, Eleanor J. Crosby, Donald A. Myers, George H. Dixon, Marjorie E. Maclachlan, Melville R. Mudge, Edwin K. Maughan, Richard P. Sheldon, Earl R. Cressman, Thomas M. Cheney, Walter E. Hallgarth, Keith B. Ketner Jan 1967

Paleotectonic Investigations Of The Permian System In The United States, Edwin D. Mckee, Stephen S. Oriel, Henry L. Berryhill, Eleanor J. Crosby, Donald A. Myers, George H. Dixon, Marjorie E. Maclachlan, Melville R. Mudge, Edwin K. Maughan, Richard P. Sheldon, Earl R. Cressman, Thomas M. Cheney, Walter E. Hallgarth, Keith B. Ketner

United States Geological Survey: Publications

(A) Allegheny region, by Henry L. Berryhill, Jr

(B) Gulf Coast region, by Eleanor J. Crosby

(C) West Texas Permian basin region, by Steven S. Oriel, Donald A. Myers, and Eleanor J. Crosby

(D) Northeastern New Mexico and Texas-Oklahoma Panhandles, by George H. Dixon

(E) Oklahoma, by Marjorie E. MacLachlan

(F) Central Midcontinent region, by Melville R. Mudge

(G) Eastern Wyoming, eastern Montana, and the Dakotas, by Edwin K. Maughan

(H) Middle Rocky Mountains and northeastern Great Basin, by Richard P. Sheldon, Earl R. Cressman, Thomas M. Cheney, and Vincent E. McKelvey

(I) Western Colorado, southern Utah, and northwestern New …


Roughness Characteristics Of Natural Channels, Harry H. Barnes Jr. Jan 1967

Roughness Characteristics Of Natural Channels, Harry H. Barnes Jr.

United States Geological Survey: Publications

Color photographs and descriptive data are presented for 50 stream channels for which roughness coefficients have been determined. All hydraulic computations involving flow in open channels require an evaluation of the roughness characteristics of the channel. In the absence of a satisfactory quantitative procedure this evaluation remains chiefly an art. The ability to evaluate roughness coefficients must be developed through experience. One means of gaining this experience is by examining and becoming acquainted with the appearance of some typical channels whose roughness coefficients are known. The photographs and data contained in this report represent a wide range of channel conditions. …


Geologic And Ground-Water Reconnaissance Of The Loup River Drainage Basin Nebraska, R. T. Sniegocki, R. H. Langford Jan 1959

Geologic And Ground-Water Reconnaissance Of The Loup River Drainage Basin Nebraska, R. T. Sniegocki, R. H. Langford

United States Geological Survey: Publications

The Loup River and its tributaries drain an area of about 15,230 square miles in central Nebraska. The upper three-fifths of the drainage basin is in the Sand Hills region of Nebraska, and the lower two-fifths is in the loess plains and hills region. An eastward-thinning wedge of semiconsolidated and unconsolidated deposits of Tertiary and Quaternary age underlies the surficial dune sand and loess. These deposits, which are recharged by infiltrating precipitation, contain a tremendous volume of water at least 400 million acre-feet and annually discharge about 1.7 million acre-feet into streams. Although wells supply nearly all the water used …


Progress Report: Chemical Quality Of The Surface Waters In The Loup River Basin, Nebraska, John G. Connor Jun 1951

Progress Report: Chemical Quality Of The Surface Waters In The Loup River Basin, Nebraska, John G. Connor

United States Geological Survey: Publications

The Loup River and its tributaries transport moderate amounts of siliceous minerals from the sand hills region of north-central Nebraska to the Platte River near Columbus, Nebr. Predominant chemical characteristics of these waters are a high percentage of silica, moderate hardness, and a low percentage of sodium. The composition of the Loup River water is influenced by the geologic formations through which ground water, a major contributor to the flows of the Loup River branches, has percolated. Investigation of water quality at or near proposed dam sites in the Loup River basin indicates that if soil and drainage conditions are …


Geologic Atlas Of The United States: Scotts Bluff Folio Nebraska, N. H. Darton Jan 1903

Geologic Atlas Of The United States: Scotts Bluff Folio Nebraska, N. H. Darton

United States Geological Survey: Publications

Explanation

The Topographic Map

The Geologic Map

Description of the Scotts Bluff Quadrangle

Geography

Geology

Stratigraphy

Eocene Period

Neocene Period

Pleistocene Period

Pre-Eocene Rocks

Brief Geological History of the Central Great Plains Region

Economic Geology

Underground WAters

Irrigation

Volcanic Ash

Ages of Rocks

Topographic Sheet

Areal Geology Sheet

Columnar Section Sheet

Illustration Sheet


The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa Dec 200

The Aerosphere As A Network Connector Of Organisms And Their Diseases, Jeremy D. Ross, Eli S. Bridge, Diann J. Prosser, John Y. Takekawa

United States Geological Survey: Staff Publications

Aeroecological processes, especially powered flight of animals, can rapidly connect biological communities across the globe. This can have profound consequences for evolutionary diversification, energy and nutrient transfers, and the spread of infectious diseases. The latter is of particular consequence for human populations, since migratory birds are known to host diseases which have a history of transmission into domestic poultry or even jumping to human hosts. In this chapter, we present a scenario under which a highly pathogenic avian influenza (HPAI) strain enters North America from East Asia via postmolting waterfowl migration. We use an agent-based model (ABM) to simulate the …