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University of Nebraska - Lincoln

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Articles 991 - 1020 of 1807

Full-Text Articles in Geology

Geomorphic And Geochemical Evidence For The Source Of Sand In The Algodones Dunes, Colorado Desert, Southeastern California, Daniel R. Muhs, Charles A. Bush, Scott D. Cowherd, Shannon Mahan Jan 1995

Geomorphic And Geochemical Evidence For The Source Of Sand In The Algodones Dunes, Colorado Desert, Southeastern California, Daniel R. Muhs, Charles A. Bush, Scott D. Cowherd, Shannon Mahan

United States Geological Survey: Staff Publications

The Algodones dunes of southeastern California comprise one of the largest active dune fields in the United States. The source of sand of the Algodones dunes is controversial, and the source of stabilized aeolian sand in the adjacent East Mesa area has not been investigated at all. We used mineralogical compositions and trace element concentrations to ascertain the most likely source of sand for these active and stabilized dunes. Results indicate that alluvium derived from the San Bernardino Mountains, which enters the Salton trough to the northwest of the dune fields, and alluvium derived from the Chocolate Mountains, which is …

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Geologic Map Of Morrill County, Nebraska, James B. Swinehart, Robert F. Diffendal Jr. Jan 1995

Geologic Map Of Morrill County, Nebraska, James B. Swinehart, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Morrill County, Nebraska, is perhaps the most geologically interesting county in the panhandle of Nebraska. Surficial deposits of alluvium, colluvium, loess, and eolian sand of Quaternary age cover large parts of the county. Holocene and latest Pleistocene(?) eolian sand as much as 150 It thick covers much of the area north of North Platte Valley and mantles Quaternary alluvial deposits to the south. A thin veneer of loess overlies bedrock in the uplands of the southern part of the county. Alluvium underlies the valley floors and caps river and stream terraces. Two units of older Quaternary alluvium are exposed in …

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Bermuda Solution Pipe Soils: A Geochemical Evaluation Of Eolian Parent Materials, Stanley R. Herwitz, Daniel R. Muhs Jan 1995

Bermuda Solution Pipe Soils: A Geochemical Evaluation Of Eolian Parent Materials, Stanley R. Herwitz, Daniel R. Muhs

United States Geological Survey: Staff Publications

Solution pipes found in the Quaternary eolian and marine carbonates of Bermuda are filled with reddish to reddish-brown soil material. The bulk of the soil is composed of clay and silt-sized quartz and aluminosilicate clay minerals. The carbonates are of high purity and, therefore, are not likely to have been the parent material. Previous workers have hypothesized that Saharan dust may have been the soil parent material. The fine-grained component of loess from the Mississippi River Valley of North America also could have contributed. Paleoclimate models indicate that both North Africa and North America could have been important source areas …

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Resource News-Summer 1995 Jan 1995

Resource News-Summer 1995

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Evidence Of Active Dune Sand On The Great Plains In The 19th Century From Accounts Of Early Explorers, Daniel R. Muhs, Vance T. Holliday Jan 1995

Evidence Of Active Dune Sand On The Great Plains In The 19th Century From Accounts Of Early Explorers, Daniel R. Muhs, Vance T. Holliday

United States Geological Survey: Staff Publications

Eolian sand is extensive over the Great Plains of North America, but is at present mostly stabilized by vegetation. Accounts published by early explorers, however, indicate that at least parts of dune fields in Nebraska, Colorado, Kansas, New Mexico, and Texas were active in the 19th century. Based on an index of dune mobility and a regional tree-ring record, the probable causes for these periods of greater eolian activity are droughts, accompanied by higher temperatures, which greatly lowered the precipitationto- evapotranspiration ratio and diminished the cover of stabilizing vegetation. In addition, observations by several explorers, and previous historical studies, indicate …

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Generalized Classification Of Economic Minerals Jan 1995

Generalized Classification Of Economic Minerals

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Carbonate Deposition, Pyramid Lake Subbasin, Nevada: 2. Lake Levels And Polar Jet Stream Positions Reconstructed From Radiocarbon Ages And Elevations Of Carbonates (Tufas) Deposited In The Lahontan Basin, Larry Benson, Michaele Kashgarian, Meyer Rubin Jan 1995

Carbonate Deposition, Pyramid Lake Subbasin, Nevada: 2. Lake Levels And Polar Jet Stream Positions Reconstructed From Radiocarbon Ages And Elevations Of Carbonates (Tufas) Deposited In The Lahontan Basin, Larry Benson, Michaele Kashgarian, Meyer Rubin

United States Geological Survey: Staff Publications

Most of the tufas in the Pyramid Lake subbasin were deposited within the last 35,000 yr, including most of the mound tufas that border the existing lake. Many of the older tufas (> 21,000 yr B.P.) contained in the mounds were formed in association with ground-water discharge. The radiocarbon (14C) ages of the older tufas represent maximum estimates of the time of their formation. Lake Lahontan experienced large and abrupt rises in level at ~ 22,000, 15,000, and 11,000 yr B.P. and three abrupt recessions in level at ~ 16,000, 13,600, and 10,000 yr B.P. The lake-level rises …

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Design Of A Multi-Level Monitoring Well For Continuous Sample Collection, J. F. Ayers, D. C. Gosselin Jan 1995

Design Of A Multi-Level Monitoring Well For Continuous Sample Collection, J. F. Ayers, D. C. Gosselin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Nebraska Groundwater In Storage, Conservation Survey Division Jan 1995

Nebraska Groundwater In Storage, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Static Pressure At The Ground Under Atmospheric Flow Across A Windbreak, James R. Brandle Jan 1995

Static Pressure At The Ground Under Atmospheric Flow Across A Windbreak, James R. Brandle

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Thayer County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1995

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Winter 1995 Jan 1995

Resource News-Winter 1995

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource News-Spring 1995 Jan 1995

Resource News-Spring 1995

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Self-Study Report 1995 Jan 1995

Self-Study Report 1995

Conservation and Survey Division: Faculty and Staff Publications

This Self-Study Report for the Conservation and Survey Division (CSD) is a profile of the unit at this point in time. It is presented in three major sections: (1) Background; (2) Current Programs and Achievements; and (3) A Vision of the Future. All sections draw heavily upon documents, staff input, and committee activities going on within the division.

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Boyd County Test Hole Logs, Susan Olafsen Lackey, Frank A. Smith, Raymond R. Burchett Jan 1995

Boyd County Test Hole Logs, Susan Olafsen Lackey, Frank A. Smith, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Resource Notes-Academic Year 1994-95 Jan 1995

Resource Notes-Academic Year 1994-95

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Guidelines For Decommissioning Water Wells, How To Plug Water Wells, Duane A. Eversoll, Delynn R. Hay, Rod J. Tremblay Jan 1995

Guidelines For Decommissioning Water Wells, How To Plug Water Wells, Duane A. Eversoll, Delynn R. Hay, Rod J. Tremblay

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Annual Outflow And Annual Inflow Of Water From/To Nebraska, 1950-1994, Conservation And Survey Division Jan 1995

Annual Outflow And Annual Inflow Of Water From/To Nebraska, 1950-1994, Conservation And Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Structural Contour Map On Top Of The Lansing Group, R. R. Burchett Jan 1995

Structural Contour Map On Top Of The Lansing Group, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Banded Agates, Origins And Inclusions, Roger K. Pabian, Andrejs Zarins Jun 1994

Banded Agates, Origins And Inclusions, Roger K. Pabian, Andrejs Zarins

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Geologic Framework Of The Niobrara River Drainage Basin And Adjacent Areas In South Dakota Generally East Of The 100th Meridian West Longitude And West Of The Missouri River, Robert F. Diffendal Jr., Michael R. Voorhies May 1994

Geologic Framework Of The Niobrara River Drainage Basin And Adjacent Areas In South Dakota Generally East Of The 100th Meridian West Longitude And West Of The Missouri River, Robert F. Diffendal Jr., Michael R. Voorhies

Department of Earth and Atmospheric Sciences: Faculty Publications

General geology and stratigraphy of the Niobrara River drainage basin in Nebraska and adjacent parts of South Dakota generally west of the Missouri River is reviewed. Of particular importance are the correlation of the Long Pine Formation of Pliocene age in Nebraska with the Herrick Gravels in South Dakota, the recognition of the members of the Ogallala Group named by Skinnner, Skinner and Gooris (1968) and by Skinner and Johnson (1984) in the basin, the acceptance of the relationships of the Miocene and older Tertiary units in the basin to those in the part of the study area in South …

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Fundamentals Of Groundwater Contamination, Darryll T. Pederson Feb 1994

Fundamentals Of Groundwater Contamination, Darryll T. Pederson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

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Environments Of Aeolian Deposition In South-Central Nebraska During The Last Glacial Maximum, Zhao-Dong Feng, William C. Johnson, Robert F. Diffendal Jr. Jan 1994

Environments Of Aeolian Deposition In South-Central Nebraska During The Last Glacial Maximum, Zhao-Dong Feng, William C. Johnson, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Peoria loess of south-central Nebraska, deposited approximately during the last Glacial Maximum, can be subdivided into three zones: an upper laminated loess and a lower massive loess, separated by a dark gley zone in which bison bones and spruce charcoal are found. The lower Peoria unit is characterized by high organic matter content, relatively high bulk density, and common root channels. The upper Peoria unit has rhythmic patterns of two orders: strongly gleyed and weakly gleyed zones alternating in couplets about 2-5 m thick, and coarse- and fine-grained laminae of second order, about 2-4 mm thick. The strongly gleyed …

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Geomorphic And Structural Features Of The Alliance 1º × 2º Quadrangle, Western Nebraska, Discernible From Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Maps, Robert F. Diffendal Jr. Jan 1994

Geomorphic And Structural Features Of The Alliance 1º × 2º Quadrangle, Western Nebraska, Discernible From Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Maps, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The digital shaded-relief map of the United States and the synthetic-aperture radar map of the Alliance Nebraska 1º x 2º area prepared by the U.S. Geological Survey (USGS) in the former case and for the USGS in the latter show oriented landforms and lineaments in northwest Nebraska. Parallel and subparallel hills and valleys developed on different geologic materials ranging from shales through sandstones to loess and eolian sand appear to be wind erosional features subsequently modified by running water. The long axes of these hills and valleys generally trend between N40"W and N50"W. Similar features also occur across major areas …

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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, …

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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.

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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.

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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 …

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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.

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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.

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