Earth Sciences Commons^™

Do Meteorologists Suppress Thunderstorms? Radar-Derived Statistics And The Behavior Of Moist Convection, Matthew D. Parker, Jason C. Knievel

Department of Earth and Atmospheric Sciences: Faculty Publications

Most meteorologists are acquainted with the notion of a weather hole—that is, a place that receives less exciting weather than does its surroundings. Exciting weather takes many forms, but when people use the term weather hole, they tend to mean a place that thunderstorms often barely miss, or near which approaching storms often dissipate. For this paper, that is the meaning we adopt.

In our experience, many meteorologists and lay weather enthusiasts genuinely believe that they live in weather holes, and this belief, almost without fail, seems to stem from countless hours spent gazing at displays of radar reflectivity. We …

Late-Holocene Dune Activity Linked To Hydrological Drought, Nebraska Sand Hills, Usa, Joseph A. Mason, James B. Swinehart, Ronald J. Goble, David B. Loope

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Hitchcock County Test Hole Logs, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Lincoln County Test Hole Logs, James W. Goeke

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Mcpherson County Test Hole Logs, James W. Goeke

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Webster County Test Hole Logs, Scott E. Summerside

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Diatom Biostratigraphy Of The Cenozoic Glaciomarine Pagodroma Group, Northern Prince Charles Mountains, East Antarctica, Jason M. Whitehead, David M. Harwood, Barrie Mckelvey, Andrew Mcminn

Department of Earth and Atmospheric Sciences: Faculty Publications

In the northern Prince Charles Mountains glaciomarine sediments of the Pagodroma Group outcrop on Fisher Massif (Mt Johnston and Fisher Bench Formations) and at the Amery Oasis (Battye Glacier and Bardin Bluffs Formations), at locations 300 and 250 km south of the Amery Ice Shelf edge, respectively. Most of the Pagodroma Group consists of ice-proximal glaciomarine diamict, and a much subordinate (<2%) amount of more ice-distal mudstone. Microfossil biostratigraphy based upon in situ and glacially reworked diatoms constrains the ages of the four formations, and identifies at least six intervals of marine fjordal deposition. Sparse diatoms in Mt Johnston Formation diamicts indicate an Early Oligocene age. However, it is …

Hydrologic Variation During The Last 170,000 Years In The Southern Hemisphere Tropics Of South America, Sherilyn C. Fritz, Paul A. Baker, Tim K. Lowenstein, Geoffrey O. Seltzer, Catherine A. Rigsby, Gary S. Dwyer, Pedro M. Tapia, Kimberly K. Arnold, Teh-Lung Ku, Shangde Luo

Department of Earth and Atmospheric Sciences: Faculty Publications

Despite the hypothesized importance of the tropics in the global climate system, few tropical paleoclimatic records extend to periods earlier than the last glacial maximum (LGM), about 20,000 years before present. We present a well-dated 170,000-year time series of hydrologic variation from the southern hemisphere tropics of South America that extends from modern times through most of the penultimate glacial period. Alternating mud and salt units in a core from Salar de Uyuni, Bolivia reflect alternations between wet and dry periods. The most striking feature of the sequence is that the duration of paleolakes increased in the late Quaternary. This …

Lewis And Clark And The Geology Of Nebraska And Parts Of Adjacent States, Robert F. Diffendal Jr., Anne P. Diffendal

School of Natural Resources: Faculty Publications

Meriwether Lewis and William Clark undertook their journey with the Corps of Discovery in 1804–1806 in order to explore the area that the United States had purchased from France in 1803. Then known as Louisiana, this region included almost everything west of the Mississippi to the continental divide (illustrated below). In order to find the best route across the continent, President Thomas Jefferson charged Lewis to follow the Missouri River to its headwaters and then locate rivers flowing down the west side of the Rocky Mountains to the Columbia River and into the Pacific Ocean. Jefferson's written instructions further specified …

Where Are The Women Geoscientist Professors?, Mary Anne Holmes, Suzanne O'Connell

Department of Earth and Atmospheric Sciences: Faculty Publications

Nearly 50 geo- and social scientists recently gathered for a workshop on women in the geosciences. The two-fold purpose was to compile data on the status of women in the geosciences, and to arrive at a consensus on strategies to increase the proportion of women and their diversity in the field. The Workshop on Women in the Geosciences was held September 25-27, 2003, in Washington, D.C.

Lewis And Clark And The Geology Of The Great Plains, Robert F. Diffendal Jr., Anne P. Diffendal

School of Natural Resources: Faculty Publications

Meriwether Lewis and William Clark undertook their journey with the Corps of Discovery in 1804-1806 in order to explore the area that the United States had purchased from France in 1803. Then known as Louisiana, this region included almost everything west of the Mississippi to the continental divide. In order to find the best route across the continent, President Thomas Jefferson charged Lewis with following the Missouri River to its headwaters and then locating rivers flowing down the west side of the Rocky Mountains to the Columbia River and into the Pacific Ocean. Jefferson's written instructions further specified that the …

Leaf And Wood Utilization In The Middle Missouri River, Kim Rager

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

New Studies Initiated By The U.S. Geological Survey: Effects Of Nutrient Enrichment On Stream Ecosystems, Mark D. Munn, Pixie A. Hamilton

United States Geological Survey: Publications

In 2001, the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program began an intensive study of nutrient enrichment—elevated concentrations of nitrogen and phosphorus— in streams in five agricultural basins across the Nation (see map, p. 2). This study is providing nationally consistent and comparable data and analyses of nutrient conditions, including how these conditions vary as a result of natural and human-related factors, and how nutrient conditions affect algae and other biological communities. This information will benefit stakeholders, including the U.S. Environmental Protection Agency (USEPA) and its partners, who are developing nutrient criteria to protect the aquatic health of streams …

Body Mass Of Late Quaternary Mammals (Data Set), Felisa A. Smith, S. Kathleen Lyons, S.K. Morgan Ernest, Kate E. Jones, Kansas State University, Tamar Dayan, Pablo A. Marquet, James H. Brown, John P. Haskell

School of Biological Sciences: Faculty Publications

The purpose of this data set was to compile body mass information for all mammals on Earth so that we could investigate the patterns of body mass seen across geographic and taxonomic space and evolutionary time. We were interested in the heritability of body size across taxonomic groups (How conserved is body mass within a genus, family, and order?), in the overall pattern of body mass across continents (Do the moments and other descriptive statistics remain the same across geographic space?), and over evolutionary time (How quickly did body mass patterns iterate on the patterns seen today? Were the Pleistocene …

Ancient Maize From Chacoan Great Houses: Where Was It Grown?, Larry Benson, Linda Cordell, Kirk Vincent, Howard E. Taylor, John Stein, G. Lang Farmer, U.S. Geological Survey

United States Geological Survey: Staff Publications

In this article, we compare chemical (⁸⁷Sr/⁸⁶Sr and elemental) analyses of archaeological maize from dated contexts within Pueblo Bonito, Chaco Canyon, New Mexico, to potential agricultural sites on the periphery of the San Juan Basin. The oldest maize analyzed from Pueblo Bonito probably was grown in an area located 80 km to the west at the base of the Chuska Mountains. The youngest maize came from the San Juan or Animas river floodplains 90 km to the north. This article demonstrates that maize, a dietary staple of southwestern Native Americans, was transported over considerable distances in …

Late-Holocene Lake-Level Variation In West Greenland, Frank A. Aebly, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Situated between the North Atlantic and the Greenland ice sheet, the thousands of lakes in the Kangerlussuaq area of West Greenland (67°N) present excellent targets for paleoclimate studies. Paleoshorelines surrounding multiple closed-basin lakes in this area record fluctuations in lake level since deglaciation. Shorelines along two of these lakes, Hundeso and Lake E, were surveyed and trenched to reconstruct the history of lake-level change. The stratigraphies of the trenches were described, and a chronology has been developed using radiocarbon dating of organic material. Preliminary results indicate a highly variable hydrologic regime throughout the late Holocene.

Hundeso had high-stand lake levels …

Applications Of Remote Sensing And Gis To The Studies Of Groundwater–Lake Interactions In The Nebraska Sandhills, Evgueni N. Tcherepanov

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Academic Specialties In U.S. Are Shifting; Hiring Of Women Geoscientists Is Stagnating, Mary Anne Holmes, Suzanne O'Connell, Connie Frey, Lois K. Ongley

Department of Earth and Atmospheric Sciences: Faculty Publications

Women have been receiving a greater proportion of the bachelor’s and master’s degrees in the geosciences over the last 10 years, reaching near 40% in 2000 (latest data available), while receiving only 28% of the Ph.D.s that year. Women are now only 20% of assistant professors at Ph.D.-granting institutions, a proportion that has not changed in the last four years. As part of a larger study to find what key barriers continue to prevent larger numbers of women geoscientists from becoming academics, data have been compiled from the National Science Board [NSB, 2002], and the American Geological Instititute's (AGI) Directory …

Sedimentary Aggregates In The Peoria Loess Of Nebraska, Usa, Joseph A. Mason, Peter M. Jacobs, Richard S. B. Greene

Department of Earth and Atmospheric Sciences: Faculty Publications

Loess grain size data used to infer transport direction or wind strength are generally derived from vigorously disaggregated samples. However, these data may not adequately represent the effective particle size distribution during loess transport, if the transported dust contained aggregates of fine-grained material. Thin sections of minimally altered C and BC horizons in the late Pleistocene Peoria Loess of Nebraska, USA, indicate the presence of aggregates with diameters of 30–1000 Am. The larger aggregates (>250 μm) are unlikely to have been transported, and are interpreted as the result of soil faunal activity and other pedogenic processes after deposition. Aggregates …

Late Quaternary Lake-Level Changes Constrained By Radiocarbon And Stable Isotope Studies On Sediment Cores From Lake Titicaca, South America, Harold D. Rowe, Thomas P. Guilderson, Robert B. Dunbar, John R. Southon, Geoffrey O. Seltzer, David A. Mucciarone, Sherilyn C. Fritz, Paul A. Baker

Department of Earth and Atmospheric Sciences: Faculty Publications

We present and compare AMS-¹⁴C geochronologies for sediment cores recovered from Lake Titicaca, South America. Radiocarbon dates from three core sites constrain the timing of late Quaternary paleoenvironmental changes in the Central Andes and highlight the site-specific factors that limit the radiocarbon geochronometer. With the exception of mid-Holocene sediments, all cores are generally devoid of macrophyte fragments, thus bulk organic fractions are used to build core chronologies. Comparisons of radiocarbon results for chemically defined fractions (bulk decalcified, humate, humin) suggest that ages derived from all fractions are generally coherent in the post-13,500 yr BP time interval. In the …

The Status Of Women In The Geosciences, Mary Anne Holmes, Connie Frey, Suzanne O'Connell, Lois K. Ongley

Department of Earth and Atmospheric Sciences: Faculty Publications

Most geoscientists agree that gender equity is a worthy goal for our field, but there is disagreement as to how to measure gender equity and what it actually means. Will the geosciences achieve gender equity when the proportion of women on our faculty and in professional positions accurately reflects the proportion in our undergraduate classes? Or is gender equity 50 percent of all positions in all fields, including undergraduate enrollment? By any of these measures, we are not yet there. Women earned 40 percent of the undergraduate degrees in geoscience (geology, oceanography, atmospheric sciences, geophysics) in 2001, and 38 percent …

Spatial And Temporal Variability In The Amount And Source Of Dissolved Organic Carbon: Implications For Ultraviolet Exposure In Amphibian Habitats, Paul D. Brooks, Catherine M. O'Reilly, Stephen A. Diamond, Don H. Campbell, Roland Knapp, David Bradford, Paul Stephen Corn, Blake Hossack, Kathy Tonnessen

United States Geological Survey: Staff Publications

The amount, chemical composition, and source of dissolved organic carbon (DOC), together with in situ ultraviolet (UV-B) attenuation, were measured at 1–2 week intervals throughout the summers of 1999, 2000, and 2001 at four sites in Rocky Mountain National Park (Colorado). Eight additional sites, four in Sequoia and Kings Canyon National Park/John Muir Wilderness (California) and four in Glacier National Park (Montana), were sampled during the summer of 2000. Attenuation of UV-B was significantly related to DOC concentrations over the three years in Rocky Mountain (R² = 0.39, F = 25.71, P < 0.0001) and across all parks in 2000 (R² = 0.44, F = 38.25, P …

Movements And Habitat Use By Shovelnose And Pallid Sturgeon In The Lower Platte River, Nebraska, Benjamin D. Swigle

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.

Landscape Change In The Southern Piedmont: Challenges, Solutions, And Uncertainty Across Scales, Michael J. Conroy, Craig R. Allen, James T. Peterson, Lowell Pritchard, Clinton T. Moore

United States Geological Survey: Staff Publications

The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships; (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, …

Are Veterinary Medicines Causing Environmental Risks?, Alistair Boxall, Dana Kolpin, Bent Holling-Sorensen, Johannes Tolls

United States Geological Survey: Staff Publications

Recently, low levels of veterinary medicines have been detected worldwide in soils, surface waters, and groundwaters (1,2). Although the impacts of selected compounds – most notably anthelmintics and selected antibacterial compounds – have been extensively investigated (3,4), many other substances found int the environment are less publicly well understood. As a result, researches have raised questions about the impact of veterinary medicines on organisms in the environment and on human health. Several key questions will be addressed in this article. What other veterinary medicines might be in the environment, and should we be concerned about these? How do these substances …

History, Geology And Water In The Lower Platte River Valley In Eastern Nebraska, Dave Gosselin, Marv Carlson, Matt Joeckel

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Southeast Nebraska Geology: Field Trip 3, Roger K. Pabian, Robert F. Diffendal, Jr. Jr., Darwin R. Boardman Ii

Robert F. Diffendal, Jr., Publications

The purpose of this trip is to familiarize you with the latest Pennsylvanian and earliest Permian rocks that are exposed in extreme southeastern Nebraska. You will see eight exposures of these rocks and will have ample opportunity to collect lithologic samples, as well as samples for both macro- and micro-fossils. The stops have been selected to show you examples of several different environments that existed in southeastern Nebraska in the late Paleozoic. These include subaerial deposits with paleosols, nearshore and offshore marine clastic and carbonate sequences. Each stop is covered in detail in the handouts that have been furnished to …

Ashfall Historic Park: Field Trip 5, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Ashfall Fossill Beds: A State Historical Park. Brochure. Nebraska Game and Parks Commission and University of Nebraska State Museum

Research Reports, 1978. Projects: A Miocene Rhinoceros Herd Buried in Volcanic Ash. Grant Recipient: Michael R. Voorhies, Division of Vertebrate Paleontology, University of Nebraska State Museum, Lincoln, Nebraska.

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. and Michael R. Voorhies. Nebraska Geological Survey Report of Investigations, number 9.

Three-Dimensional Model Of Modern Channel Bend Deposits, M. Bayani Cardenas, Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

We present a three-dimensional model of heterogeneous modern channel bend deposits developed through purely structure-imitating interpolation (kriging) of hydraulic properties. This model, augmented with ground-penetrating radar data and directional variograms, agrees with detailed observations in similar modern environments and leads to a process-based interpretation of the presented hydraulic conductivity structure. Integration of all available information permitted delineation and characterization of the modern streambed as a distinct hydrostratigraphic unit without coring or outcrop studies. Our results imply that the modern streambed is commonly oversimplified in available analytical and numerical models of groundwater-surface water interactions where it is assumed to be homogeneous …

A Late Quaternary Diatom Record Of Tropical Climatic History From Lake Titicaca (Peru And Bolivia), Pedro M. Tapia, Sherilyn C. Fritz, Paul A. Baker, Geoffrey A. Seltzer, Robert B. Dunbar

Department of Earth and Atmospheric Sciences: Faculty Publications

A composite high-resolution diatom stratigraphy from three piston cores and one box-core in the deep sub-basin of Lake Titicaca reveals large moisture variations during the past 30 kyr in the Altiplano region. Diatom sequences indicate orbital and millennial-scale variability in water level and salinity. The pelagic freshwater diatom species Cyclotella andina and Cyclotella stelligera dominate Glacial-age sediments, suggesting that the lake was above its present outlet. Generally, wet conditions continued until 11,000 cal yr BP, as indicated by high percentages of freshwater planktonic diatoms. Large pulses of benthic diatom species between about 11,000 and 10,000 cal yr BP suggest brief …