Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Nebraska - Lincoln

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 3091 - 3120 of 4541

Full-Text Articles in Earth Sciences

Dawson County Test Hole Logs, Frank A. Smith Jan 1999

Dawson County Test Hole Logs, Frank A. Smith

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Hall County Test Hole Logs, Vincent H. Dreeszen Jan 1999

Hall County Test Hole Logs, Vincent H. Dreeszen

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Evaluation Of Stream Depletion Considering Finite Stream Width, Shallow Penetration, And Properties Of Streambed Sediments, Vitaly A. Zlotnik, Huihua Huang, James J. Butler Jr. Jan 1999

Evaluation Of Stream Depletion Considering Finite Stream Width, Shallow Penetration, And Properties Of Streambed Sediments, Vitaly A. Zlotnik, Huihua Huang, James J. Butler Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

Commonly used methods for estimation of pumping-induced stream depletion are based on a series of idealistic assumptions about the stream-aquifer interface. In many cases, however, these assumptions are not consistent with field conditions. In order to obtain stream-depletion estimates that are based on assumptions more appropriate for conditions often faced in the field, a new analytical model is proposed. This model, which incorporates the effects of finite stream width, shallow stream penetration, and a low permeability streambed, is based on the Dupuit assumptions and a steady-state representation of flow across the streambed. A general solution for stream depletion is developed …

Go to article

Lethal Sandslides From Eolian Dunes, David B. Loope, Joseph A. Mason, Lowell Dingus Jan 1999

Lethal Sandslides From Eolian Dunes, David B. Loope, Joseph A. Mason, Lowell Dingus

Department of Earth and Atmospheric Sciences: Faculty Publications

Fossil vertebrates entombed within the Upper Cretaceous Djadokhta Formation of southern Mongolia bear testimony to a heretofore unknown geologic phenomenon: mass wasting of eolian dunes during heavy rainstorms. Evaporation of shallow-penetrating rainwater led to progressive calcite accumulation in a thin layer of sand about 0.5 m below the surface of dune lee slopes. During rare heavy rainstorms, a perched water table developed at the top of calcitic zones. Positive pore water pressure led to translational slides and fast-moving sediment gravity flows that overwhelmed animals on the lee slopes of large dunes and in interdune areas.

Go to article

Monitoring The 1996 Drought Using The Standardized Precipitation Index, Michael J. Hayes, Mark D. Svoboda, Donald A. Wilhite, Olga V. Vanyarkho Jan 1999

Monitoring The 1996 Drought Using The Standardized Precipitation Index, Michael J. Hayes, Mark D. Svoboda, Donald A. Wilhite, Olga V. Vanyarkho

National Drought Mitigation Center: Faculty Publications

Droughts are difficult to detect and monitor. Drought indices, most commonly the Palmer Drought Severity Index (PDSI), have been used with limited success as operational drought monitoring tools and triggers for policy responses. Recently, a new index, the Standardized Precipitation Index (SPI), was developed to improve drought detection and monitoring capabilities. The SPI has several characteristics that are an improvement over previous indices, including its simplicity and temporal flexibility, that allow its application for water resources on all timescales. In this article, the 1996 drought in the southern plains and southwestern United States is examined using the SPI. A series …

Go to article

Surface Features Of The Salt Basin Of Lancaster County, Nebraska, R. M. Joeckel, B. A. Clement Jan 1999

Surface Features Of The Salt Basin Of Lancaster County, Nebraska, R. M. Joeckel, B. A. Clement

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Groundwater-Level Changes In Nebraska, Predevelopment To Spring 1997/Registered Irrigation Wells In Nebraska-Spring 1997, Conservation Survey Division, Jennifer Stanton, Ann Mack, Jim Weir Jan 1999

Groundwater-Level Changes In Nebraska, Predevelopment To Spring 1997/Registered Irrigation Wells In Nebraska-Spring 1997, Conservation Survey Division, Jennifer Stanton, Ann Mack, Jim Weir

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Acres Irrigated In Nebraska - Past, Present, And Future, Bryce B. Pease Jan 1999

Acres Irrigated In Nebraska - Past, Present, And Future, Bryce B. Pease

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Resource Notes-Academic Year 1998-99 Jan 1999

Resource Notes-Academic Year 1998-99

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

A Memorial For William V. Sliter, Robert G. Douglas, Jere H. Lipps, James C. Ingle Jr., John Barron Jan 1999

A Memorial For William V. Sliter, Robert G. Douglas, Jere H. Lipps, James C. Ingle Jr., John Barron

United States Geological Survey: Staff Publications

William V. (Bill) Sliter, an internationally known micropaleontologist and research geologist for the U.S. Geological Survey, passed away suddenly, October, 1997, while talking to a colleague in his office. In his honor, B. Huber, T. Bralower, and M. Leckie organized a keynote symposium ‘‘Paleoecological and Geochemical Signatures of Cretaceous Anoxic Events’’ at the 1998 annual meeting of the Geological Society of America in Toronto, Canada. This theme issue of the Journal of Foraminiferal Research contains the published papers from the symposium and is dedicated to his memory.

Go to article

Comparison Of An Enzyme-Linked Immunosorbent Assay (Elisa) To Gas Chromatography (Gc) - Measurement Of Polychlorinated Biphenyls (Pcbs) In Selected Us Fish Extracts, James L. Zajicek, Donald E. Tillitt, Ted R. Schwartz, Christopher J. Schmitt, Robert O. Harrison Jan 1999

Comparison Of An Enzyme-Linked Immunosorbent Assay (Elisa) To Gas Chromatography (Gc) - Measurement Of Polychlorinated Biphenyls (Pcbs) In Selected Us Fish Extracts, James L. Zajicek, Donald E. Tillitt, Ted R. Schwartz, Christopher J. Schmitt, Robert O. Harrison

United States Geological Survey: Staff Publications

The analysis of PCBs in fish tissues by immunoassay methods was evaluated using fish collected from a US monitoring program, the National Contaminant Biomonitoring Program of the US Department of Interior, Fish and Wildlife Service. Selected composite whole fish samples, which represented widely varying concentrations and sources of PCBs, were extracted and subjected to congener PCB analysis by gas chromatography (GC) and total PCB analysis using an ELISA (ePCBs) calibrated against technical Aroclor 1248. PCB congener patterns in these fishes were different from the patterns found in commercial Aroclors or their combinations as demonstrated by principal component analysis of normalized …

Go to article

Biogenic Silica Records From The Bdp93 Drill Site And Adjacent Areas Of The Selenga Delta, Lake Baikal, Siberia, Steven M. Colman, John A. Peck, Josephine Hatton, Eugene B. Karabanov, John W. King Jan 1999

Biogenic Silica Records From The Bdp93 Drill Site And Adjacent Areas Of The Selenga Delta, Lake Baikal, Siberia, Steven M. Colman, John A. Peck, Josephine Hatton, Eugene B. Karabanov, John W. King

United States Geological Survey: Staff Publications

Biogenic silica contents of sediments on the lower Selenga Delta and Buguldeika saddle in Lake Baikal show distinct fluctuations that reflect changes in diatom productivity, and ultimately, climate. The pattern of the upper 50 m of the section, dating from about 334 ka, is similar to that of the marine oxygen isotope record, increasingly so as the younger sediments become progressively finer grained and less locally derived with time. The last two interglaciations are marked by biogenic silica abundances similar to those of the Holocene. The equivalent of marine oxygenisotope stage 3 is distinctly intermediate in character between full glacial …

Go to article

The Carbon Cycle And Biogeochemical Dynamics In Lake Sediments, Walter E. Dean Jan 1999

The Carbon Cycle And Biogeochemical Dynamics In Lake Sediments, Walter E. Dean

United States Geological Survey: Staff Publications

The concentrations of organic carbon (OC) and CaCO3 in lake sediments are often inversely related. This relation occurs in surface sediments from different locations in the same lake, surface sediments from different lakes, and with depth in Holocene sediments. Where data on accumulation rates are available, the relation holds for organic carbon and CaCO3 accumulation rates as well. An increase of several percent OC is accompanied by a decrease of several tens of percent CaCO3 indicating that the inverse relation is not due to simple dilution of one component by another. It appears from core data that …

Go to article

200,000 Years Of Climate Change Recorded In Eolian Sediments Of The High Plains Of Eastern Colorado And Western Nebraska, Daniel R. Muhs, James Swinehart, David Loope, John N. Aleinikoff, Josh Been Jan 1999

200,000 Years Of Climate Change Recorded In Eolian Sediments Of The High Plains Of Eastern Colorado And Western Nebraska, Daniel R. Muhs, James Swinehart, David Loope, John N. Aleinikoff, Josh Been

United States Geological Survey: Staff Publications

Loess and eolian sand cover vast areas of the western Great Plains of Nebraska, Kansas and Colorado (Fig. 1). In recent studies of Quaternary climate change, there has been a renewed interest in loess and eolian sand. Much of the attention now given to loess stems from new studies of long loess sequences that contain detailed records of Quaternary glacial-interglacial cycles, thought to be a terrestrial equivalent to the foraminiferal oxygen isotope record in deep-sea sediments (Fig. 2). Loess is also a direct record of atmospheric circulation, and identification of loess paleowinds in the geologic record can test atmospheric general …

Go to article

Slip-Parallel Seismic Lineations On The Northern Hayward Fault, California, Felix Waldhauser, William L. Ellsworth, Alex Cole Jan 1999

Slip-Parallel Seismic Lineations On The Northern Hayward Fault, California, Felix Waldhauser, William L. Ellsworth, Alex Cole

United States Geological Survey: Staff Publications

A high-resolution relative earthquake location procedure is used to image the fine-scale seismicity structure of the northern Hayward fault, California. The seismicity defines a narrow, near-vertical fault zone containing horizontal alignments of hypocenters extending along the fault zone. The lineations persist over the 15-year observation interval, implying the localization of conditions on the fault where brittle failure conditions are met. The horizontal orientation of the lineations parallels the slip direction of the fault, suggesting that they are the result of the smearing of frictionally weak material along the fault plane over thousands of years.

Go to article

Late Quaternary Loess In Northeastern Colorado: Part I—Age And Paleoclimatic Significance, Daniel R. Muhs, John N. Aleinikoff, Thomas W. Stafford Jr., Rolf Kihl, Josh Been, Shannon A. Mahan, Scott Cowherd Jan 1999

Late Quaternary Loess In Northeastern Colorado: Part I—Age And Paleoclimatic Significance, Daniel R. Muhs, John N. Aleinikoff, Thomas W. Stafford Jr., Rolf Kihl, Josh Been, Shannon A. Mahan, Scott Cowherd

United States Geological Survey: Staff Publications

Loess in eastern Colorado covers an estimated 14,000 km2, and is the westernmost part of the North American midcontinent loess province. Stratigraphic studies indicate there were two periods of loess deposition in eastern Colorado during late Quaternary time. The first period spanned ca. 20,000 to 12,000 14C yr B.P. (ca. 20–14 ka) and correlates reasonably well with the culmination and retreat of Pinedale glaciers in the Colorado Front Range during the last glacial maximum. The second period of loess deposition occurred between ca. 11,000 and 9,000 14C yr B.P. This interval may be Holocene or may …

Go to article

Late Quaternary Loess In Northeastern Colorado: Part Ii—Pb Isotopic Evidence For The Variability Of Loess Sources, John N. Aleinikoff, Daniel R. Muhs, Rebecca R. Sauer, C. Mark Fanning Jan 1999

Late Quaternary Loess In Northeastern Colorado: Part Ii—Pb Isotopic Evidence For The Variability Of Loess Sources, John N. Aleinikoff, Daniel R. Muhs, Rebecca R. Sauer, C. Mark Fanning

United States Geological Survey: Staff Publications

A new application of the Pb isotopic tracer technique has been used to determine the relative importance of different silt sources for late Wisconsin loess in the central Great Plains of eastern Colorado. Samples of the Peoria Loess collected throughout the study area contain K-feldspar derived from two isotopically and genetically distinct sources: (1) glaciogenic material from Early and Middle Proterozoic crystalline rocks of the Colorado province, and (2) volcaniclastic material from the Tertiary White River Group exposed on the northern Great Plains. Pb isotopic compositions of K-feldspar in loess from two dated vertical sections (at Beecher Island and Last …

Go to article

Predation Of Artificial Ground Nests On White-Tailed Prairie Dog Colonies, Bruce W. Baker, Thomas R. Stanley, James A. Sedgwick Jan 1999

Predation Of Artificial Ground Nests On White-Tailed Prairie Dog Colonies, Bruce W. Baker, Thomas R. Stanley, James A. Sedgwick

United States Geological Survey: Staff Publications

Prairie dog (Cynomys spp.) colonies are unique to prairie and shrub-steppe landscapes. However, widespread eradication, habitat loss, and sylvatic plague (Yersinia pestis) have reduced their numbers by 98% since historical times. Birds associated with prairie dogs also are declining. Potential nest predators, such as coyotes (Canis latrans), swift foxes (Vulpes velox), and badgers (Taxidea taxus), may be attracted to colonies where a high concentration of prairie dogs serve as available prey. Increased abundance of small mammals, including prairie dogs, also may increase the risk of predation for birds nesting on colonies. …

Go to article

Atrazine Degradation In A Small Stream In Iowa, Dana W. Kolpin, Stephen J. Kalkhoff Jan 1999

Atrazine Degradation In A Small Stream In Iowa, Dana W. Kolpin, Stephen J. Kalkhoff

United States Geological Survey: Staff Publications

A study was conducted during 1990 through an 11.2-km reach of Roberts Creek in northeastern Iowa to determine the fate of atrazine in a surface water environment. Water samples were collected at ~1-month intervals from April through November during stable low to medium flow conditions and analyzed for atrazine and two of its initial biotic degradation products, desethylatrazine and deisopropylatrazine. Samples were collected on the basis of a Lagrangian model of streamflow in order to sample the same parcel of water as it moved downstream. Atrazine concentrations substantially decreased (roughly 25-60% ) between water entering and exiting the study reach …

Go to article

Are Shifts In Herbicide Use Reflected In Concentration Changes In Midwestern Rivers?, William Battaglin, Donald Goolsby Jan 1999

Are Shifts In Herbicide Use Reflected In Concentration Changes In Midwestern Rivers?, William Battaglin, Donald Goolsby

United States Geological Survey: Staff Publications

In many Midwestern rivers, elevated concentrations of herbicides occur during runoff events for 1-3 months following application. The highest or “peak” herbicide concentration often occurs during one of these runoff events. Herbicide concentrations in rivers are affected by a number of factors, including herbicide use patterns within the associated basin. Changing agricultural practices, reductions in recommended and permitted herbicide applications, shifts to new herbicides, and greater environmental awareness in the agricultural community have resulted in changes to herbicide use patterns. In the Midwestern United States, alachlor use was much larger in 1989 than in 1995, while acetochlor was not used …

Go to article

Negative Ph, Efflorescent Mineralogy, And Consequences For Environmental Restoration At The Iron Mountain Superfund Site, California, D. Kirk Nordstrom, Charles N. Alpers Jan 1999

Negative Ph, Efflorescent Mineralogy, And Consequences For Environmental Restoration At The Iron Mountain Superfund Site, California, D. Kirk Nordstrom, Charles N. Alpers

United States Geological Survey: Staff Publications

The Richmond Mine of the Iron Mountain copper deposit contains some of the most acid mine waters ever reported. Values of pH have been measured as low as -3.6, combined metal concentrations as high as 200 g/liter, and sulfate concentrations as high as 760 g/liter. Copious quantities of soluble metal sulfate salts such as melanterite, chalcanthite, coquimbite, rhomboclase, voltaite, copiapite, and halotrichite have been identified, and some of these are forming from negative-pH mine waters. Geochemical calculations show that, under a mine-plugging remediation scenario, these salts would dissolve and the resultant 600,000-m3 mine pool would have a pH of …

Go to article

Resource News-Spring 1999 Jan 1999

Resource News-Spring 1999

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

2018 Nebraska Water Leaders Academy - Final Report, Mark E. Burbach Jan 1999

2018 Nebraska Water Leaders Academy - Final Report, Mark E. Burbach

Conservation and Survey Division: Faculty and Staff Publications

Nineteen participants completed the 2018 Water Leaders Academy bringing the total number of graduates to 120 since the inception of the program in 2011. Assessment of participants’ transformational leadership skills, champion of innovation skills, water knowledge and engagement, civic capacity, and entrepreneurial leadership behaviors showed a significant increase over the course of the year, from both participants’ and their raters’ perspectives. Feedback from participants was highly positive and constructive. Participant concerns were addressed, and only minor changes are planned for the 2019 Academy curriculum. Results of the program assessment indicate that the curriculum is meeting Academy objectives. Most importantly, Alumni …

Go to article

Hydrologic Setting Of Two Interdunal Valleys In The Central Sand Hills Nebraska, D. C. Gosselin, S. Drda, F. E. Harvey, J. Goeke Jan 1999

Hydrologic Setting Of Two Interdunal Valleys In The Central Sand Hills Nebraska, D. C. Gosselin, S. Drda, F. E. Harvey, J. Goeke

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Reconnaissance Water Quality Study Of The Dakota Aquifer In Lancaster County, Nebraska, J. Anderson, D. D. Gosselin Jan 1999

Reconnaissance Water Quality Study Of The Dakota Aquifer In Lancaster County, Nebraska, J. Anderson, D. D. Gosselin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Groundwater-Level Changes In Nebraska, 1996, Abraham H. Chen, Mohan J. Khisty Jan 1999

Groundwater-Level Changes In Nebraska, 1996, Abraham H. Chen, Mohan J. Khisty

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Douglas County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1999

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Hamilton County Test Hole Logs, Perry B. Wigley Jan 1999

Hamilton County Test Hole Logs, Perry B. Wigley

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Sarpy County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1999

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

Wayne County Test Hole Logs, Sue Olafsen Lackey, Frank A. Smith, Raymond R. Burchett Jan 1999

Wayne County Test Hole Logs, Sue Olafsen Lackey, Frank A. Smith, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Go to article

First Prev Next Last