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Articles 1 - 26 of 26
Full-Text Articles in Physical Sciences and Mathematics
Publications And Other Works By R. F. Diffendal, Jr., Robert F. Diffendal
Publications And Other Works By R. F. Diffendal, Jr., Robert F. Diffendal
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Updated March 2021
Chronology Of Advance And Recession Dynamics Of The Southern Green Bay Lobe Of The Laurentide Ice Sheet, South-Central Wisconsin, Usa, Eric C. Carson, John W. Attig, J. Elmo Rawling Iii, Paul R. Hanson, Stefanie E. Dodge
Chronology Of Advance And Recession Dynamics Of The Southern Green Bay Lobe Of The Laurentide Ice Sheet, South-Central Wisconsin, Usa, Eric C. Carson, John W. Attig, J. Elmo Rawling Iii, Paul R. Hanson, Stefanie E. Dodge
Papers in Natural Resources
We used a combination of accelerator mass spectrometry (AMS) radiocarbon dating, optically stimulated luminescence (OSL) age estimates, and stratigraphic data from cores collected along the southern margin of the Green Bay Lobe (GBL) of the Laurentide Ice Sheet to provide new information on the timing and dynamics of the end of advance of the GBL and the dynamics of the ice sheet while very near its maximum position. Coring at multiple sites along the margin of the GBL indicate that ice had reached a stable position near its maximum extent by 24.7 ka; that ice advanced several kilometers to the …
Anthropogenic Hydrometeorological Changes At A Regional Scale: Observed Irrigation-Precipitation Feedback (1979-2015) In Nebraska, Usa, Jozsef Szilagyi, Trenton Franz
Anthropogenic Hydrometeorological Changes At A Regional Scale: Observed Irrigation-Precipitation Feedback (1979-2015) In Nebraska, Usa, Jozsef Szilagyi, Trenton Franz
Papers in Natural Resources
Long-term tendencies in annual, seasonal, and monthly (March) precipitation, evapotranspiration, and air- and dew-point temperature values were correlated with county-level changes in irrigated area across Nebraska over the 1979–2015 period. A statistically significant linear relationship (slope of − 1.65 ± 0.33 mm/decade per % decadal change in irrigated area, with a correlation coefficient of − 0.47) was found between the trends in annual precipitation and irrigated land area. Precipitation dropped by 1 mm annually if the level in irrigation expansion reached about 8% per decade, while the rest of the state enjoyed about a half-millimeter overall increase in annual precipitation …
Catchment Size Is An Important Factor In Mapping Long-Term Flood Behaviour, Jozsef Szilagyi, Janos Jozsa, Eszter Dora Nagy, Tamas Kramer, Marta Farkas Spitzerne
Catchment Size Is An Important Factor In Mapping Long-Term Flood Behaviour, Jozsef Szilagyi, Janos Jozsa, Eszter Dora Nagy, Tamas Kramer, Marta Farkas Spitzerne
Papers in Natural Resources
From an analysis of 3,738 river gauging stationsof catchments ranging from 5 to 100,000 km2, Blöschl et al. constructed a map that depicts trends of annual maximum discharges across Europe for the 1960-2010 period. On that map Hungary, one of the most flood-prone countries in Europe, appears with nearly unanimously decreasing flood discharges which is in stark contrast with the reality of worsening floods on the Danube over the past 50-60 years in Hungary, costing €58 million in flood defence in 2013 alone, a year with record-breaking flood. The contradiction arises due to differences in scale for the …
Chronology Of Dune Development In The White River Badlands, Northern Great Plains, Usa, P. E. Baldauf, P. A. Burkhart, Paul R. Hanson, M. Miles, Ashley Larsen
Chronology Of Dune Development In The White River Badlands, Northern Great Plains, Usa, P. E. Baldauf, P. A. Burkhart, Paul R. Hanson, M. Miles, Ashley Larsen
Papers in Natural Resources
Aeolian dune field chronologies provide important information on drought history on the Great Plains. The White River Badlands (WRB) dunes are located approximately 60 km north of the Nebraska Sand Hills (NSH), in the western section of the northern Great Plains. Clifftop dunes, sand sheets, and stabilized northwest-southeast trending parabolic dunes are found on upland mesas and buttes, locally called tables. The result of this study is a dune stabilization history determined from samples collected from stratigraphic exposures and dune crests. Thirty-seven OSL ages, from this and previous investigations, show three periods of dune activity: 1) ~21,000 years ago to …
Uncertainty In Simulating Gross Primary Production Of Cropland Ecosystem From Satellite-Based Models, Wenping Yuan, Wenwen Cai, Anthony L. Nguy-Robertson, Huajun Fang, Andrew E. Suyker, Yang Chen, Wenjie Dong, Shuguang Liu, Haicheng Zhang
Uncertainty In Simulating Gross Primary Production Of Cropland Ecosystem From Satellite-Based Models, Wenping Yuan, Wenwen Cai, Anthony L. Nguy-Robertson, Huajun Fang, Andrew E. Suyker, Yang Chen, Wenjie Dong, Shuguang Liu, Haicheng Zhang
Papers in Natural Resources
Accurate estimates of gross primary production (GPP) for croplands are needed to assess carbon cycle and crop yield. Satellite-based models have been developed to monitor spatial and temporal GPP patterns. However, there are still large uncertainties in estimating cropland GPP. This study compares three light use efficiency (LUE) models (MODIS-GPP, EC-LUE, and VPM) with eddy-covariance measurements at three adjacent AmeriFlux crop sites located near Mead, Nebraska, USA. These sites have different croprotation systems (continuous maize vs. maize and soybean rotated annually) and water management practices (irrigation vs. rainfed). The results reveal several major uncertainties in estimating GPP which need to …
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
Papers in Natural Resources
Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, …
A Geospatial Approach For Prioritizing Wind Farm Development In Northeast Nebraska, Usa, Adam Miller, Ruopu Li
A Geospatial Approach For Prioritizing Wind Farm Development In Northeast Nebraska, Usa, Adam Miller, Ruopu Li
Papers in Natural Resources
Being cleaner and climate friendly, wind energy has been increasingly utilized to meet the ever-growing global energy demands. In the State of Nebraska, USA, a wide gap exists between wind resource and actual energy production, and it is imperative to expand the wind energy development. Because of the formidable costs associated with wind energy development, the locations for new wind turbines need to be carefully selected to provide the greatest benefit for a given investment. Geographic Information Systems (GIS) have been widely used to identify the suitable wind farm locations. In this study, a GIS-based multi-criteria approach was developed to …
Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Beverly E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker
Data-Driven Diagnostics Of Terrestrial Carbon Dynamics Over North America, Jingfeng Xiao, Scott V. Ollinger, Steve Frolking, George Hurtt, David Y. Hollinger, Kenneth J. Davis, Yude Pan, Xiaoyang Zhang, Feng Deng, Jiquan Chen, Dennis D. Baldocchi, Beverly E. Law, M. Altaf Arain, Ankur R. Desai, Andrew D. Richardson, Ge Sun, Brian Amiro, Hank Margolis, Lianhong Gu, Russell L. Scott, Peter D. Blanken, Andrew E. Suyker
Papers in Natural Resources
The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth’s climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale eddy covariance flux observations from towers to the continental scale by integrating flux observations, meteorology, stand age,aboveground biomass, and a proxy for canopy nitrogen concentrations from AmeriFlux and Fluxnet-Canada Research Network as well as a variety of satellite data streams from the MODIS sensors. …
Landsat-8: Science And Product Vision For Terrestrial Global Change Research, David P. Roy, M. A. Wulder, T. R. Loveland, C. E. Woodcock, R. G. Allen, M. C. Anderson, D. Helder, J. R. Irons, D. M. Johnson, R. Kennedy, T. A. Scambos, C. B. Schaaf, J. R. Schott, Y. Sheng, E. F. Vermote, A. S. Belward, R. Bindschadler, W. B. Cohen, F. Gao, J. D. Hipple, P. Hostert, Desert Research Institute, Reno, Nv, C. O. Justice, Ayse Kilic, V. Kovalskyy, Z. P. Lee, L. Lymburner, J. G. Masek, J. Mccorkel, Y. Shuai, R. Trezza, J. Vogelmann, R. H. Wynne, Z. Zhu
Landsat-8: Science And Product Vision For Terrestrial Global Change Research, David P. Roy, M. A. Wulder, T. R. Loveland, C. E. Woodcock, R. G. Allen, M. C. Anderson, D. Helder, J. R. Irons, D. M. Johnson, R. Kennedy, T. A. Scambos, C. B. Schaaf, J. R. Schott, Y. Sheng, E. F. Vermote, A. S. Belward, R. Bindschadler, W. B. Cohen, F. Gao, J. D. Hipple, P. Hostert, Desert Research Institute, Reno, Nv, C. O. Justice, Ayse Kilic, V. Kovalskyy, Z. P. Lee, L. Lymburner, J. G. Masek, J. Mccorkel, Y. Shuai, R. Trezza, J. Vogelmann, R. H. Wynne, Z. Zhu
Papers in Natural Resources
Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of …
Estimation Of Crop Gross Primary Production (Gpp): FaparChl Versus Mod15a2 Fpar, Qingyuan Zhang, Yen-Ben Cheng, A. I. Lyapustin, Yujie Wang, Feng Gao, Andrew E. Suyker, Shashi B. Verma, Elizabeth M. Middleton
Estimation Of Crop Gross Primary Production (Gpp): FaparChl Versus Mod15a2 Fpar, Qingyuan Zhang, Yen-Ben Cheng, A. I. Lyapustin, Yujie Wang, Feng Gao, Andrew E. Suyker, Shashi B. Verma, Elizabeth M. Middleton
Papers in Natural Resources
Photosynthesis (PSN) is a pigment level process in which antenna pigments (predominately chlorophylls) in chloroplasts absorb photosynthetically active radiation (PAR) for the photochemical process. PAR absorbed by foliar non-photosynthetic components is not used for PSN. The fraction of PAR absorbed (fAPAR) by a canopy/vegetation (i.e., fAPARcanopy) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) images, referred to as MOD15A2 FPAR, has been used to compute absorbed PAR (APAR) for PSN (APARPSN) which is utilized to produce the standard MODIS gross primary production (GPP) product, referred to as MOD17A2 GPP. In this study, the fraction of PAR …
Drainage Structure Datasets And Effects On Lidar-Derived Surface Flow Modeling, Ruopu Li, Zhenghong Tang, Xu Li, Jessie Winter
Drainage Structure Datasets And Effects On Lidar-Derived Surface Flow Modeling, Ruopu Li, Zhenghong Tang, Xu Li, Jessie Winter
Papers in Natural Resources
With extraordinary resolution and accuracy, Light Detection and Ranging (LiDAR)-derived digital elevation models (DEMs) have been increasingly used for watershed analyses and modeling by hydrologists, planners and engineers. Such high-accuracy DEMs have demonstrated their effectiveness in delineating watershed and drainage patterns at fine scales in low-relief terrains. However, these high-resolution datasets are usually only available as topographic DEMs rather than hydrologic DEMs, presenting greater land roughness that can affect natural flow accumulation. Specifically, locations of drainage structures such as road culverts and bridges were simulated as barriers to the passage of drainage. This paper proposed a geospatial method for producing …
Transforming The Teaching Of Geoscience And Sustainability, David Gosselin, Cathy Manduca, Timothy J. Bralower, David Mogk
Transforming The Teaching Of Geoscience And Sustainability, David Gosselin, Cathy Manduca, Timothy J. Bralower, David Mogk
Papers in Natural Resources
The geosciences have an important role to play in addressing whether humans can live sustainably on Earth. From water to energy, from climate change to natural hazards, geoscience is central to solving a wide range of problems.
Two projects funded by the National Science Foundation (NSF) support faculty in incorporating aspects of sustainability in their teaching: the Interdisciplinary Teaching of Geoscience for a Sustainable Future ( InTeGrate) Center in the Geosciences and the On the Cutting Edge Faculty Development Program in the Geosciences. The former is funded by NSF’s Science Technology, Engineering, and Mathematics (STEM) Faculty Development Program, and the …
Modeling Vulnerability Of Groundwater To Pollution Under Future Scenarios Of Climate Change And Biofuels-Related Land Use Change: A Case Study In North Dakota, Usa, Ruopu Li, James W. Merchant
Modeling Vulnerability Of Groundwater To Pollution Under Future Scenarios Of Climate Change And Biofuels-Related Land Use Change: A Case Study In North Dakota, Usa, Ruopu Li, James W. Merchant
Papers in Natural Resources
Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality.Most groundwater vulnerability modeling has been based on current hydrogeology and land use condi- tions. However, groundwater vulnerability is strongly dependent on factors such as depth-to-water, recharge and land use conditions thatmay change in response to future changes in climate and/or socio-economic condi- tions. In this research, a modeling framework, which employs three sets of models linked within a geographic information system (GIS) environment, was used to evaluate groundwater pollution risks under future climate and land use changes in North Dakota. The results showed that areas with …
Interannual And Spatial Impacts Of Phenological Transitions, Growing Season Length, And Spring And Autumn Temperatures On Carbon Sequestration: A North America Flux Data Synthesis, Chaoyang Wu, Alemu Gonsamo, Jing Ming Chen, Werner A. Kurz, David T. Price, Peter M. Lafleur, Rachhpal S. Jassal, Danilo Dragoni, Gil Bohrer, Christopher M. Gough, Shashi B. Verma, Andrew E. Suyker, J. William Munger
Interannual And Spatial Impacts Of Phenological Transitions, Growing Season Length, And Spring And Autumn Temperatures On Carbon Sequestration: A North America Flux Data Synthesis, Chaoyang Wu, Alemu Gonsamo, Jing Ming Chen, Werner A. Kurz, David T. Price, Peter M. Lafleur, Rachhpal S. Jassal, Danilo Dragoni, Gil Bohrer, Christopher M. Gough, Shashi B. Verma, Andrew E. Suyker, J. William Munger
Papers in Natural Resources
Understanding feedbacks of ecosystem carbon sequestration to climate change is an urgent step in developing future ecosystem models. Using 187 site-years of flux data observed at 24 sites covering three plant functional types (i.e. evergreen forests (EF), deciduous forests (DF) and non-forest ecosystems (NF) (e.g., crop, grassland, wetland)) in North America, we present an analysis of both interannual and spatial relationships between annual net ecosystem production (NEP) and phenological indicators, including the flux-based carbon uptake period (CUP) and its transitions, degree-day-derived growing season length (GSL), and spring and autumn temperatures. Diverse responses were acquired between annul NEP and these indicators …
Nir-Red Reflectance-Based Algorithms For Chlorophyll-A Estimation In Mesotrophic Inland And Coastal Waters: Lake Kinneret Case Study, Yosef Z. Yacobi, Wesley Moses, Semion Kaganovsky, Benayahu Sulimani, Bryan Leavitt, Anatoly A. Gitelson
Nir-Red Reflectance-Based Algorithms For Chlorophyll-A Estimation In Mesotrophic Inland And Coastal Waters: Lake Kinneret Case Study, Yosef Z. Yacobi, Wesley Moses, Semion Kaganovsky, Benayahu Sulimani, Bryan Leavitt, Anatoly A. Gitelson
Papers in Natural Resources
A variety of models have been developed for estimating chlorophyll-a (Chl-a) concentration in turbid and productive waters. All are based on optical information in a few spectral bands in the red and near-infra-red regions of the electromagnetic spectrum. The wavelength locations in the models used were meticulously tuned to provide the highest sensitivity to the presence of Chl-a and minimal sensitivity to other constituents in water. But the caveat in these models is the need for recurrent parameterization and calibration due to changes in the biophysical characteristics of water based on the location and/or time of the year. In this …
Modeling Gross Primary Production Of Irrigated And Rain-Fed Maize Using Modis Imagery And Co2 Flux Tower Data, Joshua L. Kalfas, Xiangming Xiao, Diana X. Vanegas, Shashi B. Verma, Andrew E. Suyker
Modeling Gross Primary Production Of Irrigated And Rain-Fed Maize Using Modis Imagery And Co2 Flux Tower Data, Joshua L. Kalfas, Xiangming Xiao, Diana X. Vanegas, Shashi B. Verma, Andrew E. Suyker
Papers in Natural Resources
Abstract
Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO2 between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation …
Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi
Estimation Of Chlorophyll-A Concentration In Case Ii Waters Using Modis And Meris Data—Successes And Challenges, Wesley Moses, Anatoly Gitelson, Sergey Berdnikov, Vasiliy Povazhnyi
Papers in Natural Resources
We present and discuss here the results of our work using MODIS (moderate resolution imaging spectroradiometer) and MERIS (medium resolution imaging spectrometer) satellite data to estimate the concentration of chlorophyll-a (chl-a) in reservoirs of the Dnieper River and the Sea of Azov, which are typical case II waters, i.e., turbid and productive. Our objective was to test the potential of satellite remote sensing as a tool for near-real-time monitoring of chl-a distribution in these water bodies. We tested the performance of a recently developed three-band model, and its special case, a two-band model, which use the reflectance at red and …
Quality Control Of Soil Water Data In Applied Climate, Jinshing You, Kenneth Hubbard, Rezaul Mamood, Venkataramana Sridhar, Dennis Todey
Quality Control Of Soil Water Data In Applied Climate, Jinshing You, Kenneth Hubbard, Rezaul Mamood, Venkataramana Sridhar, Dennis Todey
Papers in Natural Resources
Abstract: Soil moisture is a key state variable from both climate and hydrologic cycle assessment perspectives. Recently, automated measurements of soil moisture with sensors deployed at sites in a real-time monitoring network have provided valuable new data to monitor the soil water resource. However, to assure the quality of the data, quality control QC tools are needed. Earlier studies left little literature on the QC of soil water data as measurements were generally not part of a network that routinely collected measurements. This paper presents a systematic QC analysis and methodology to evaluate the performance of candidate QC techniques using …
Vertical Movement Of Water In A High Plains Aquifer Induced By A Pumping Well, Xunhong Chen, Yanfeng Yin, James W. Goeke, Robert F. Diffendal
Vertical Movement Of Water In A High Plains Aquifer Induced By A Pumping Well, Xunhong Chen, Yanfeng Yin, James W. Goeke, Robert F. Diffendal
Papers in Natural Resources
Field observation and numerical simulations were carried out to evaluate the hydraulic relationship between the shallow and deep aquifer of a High Plains Aquifer system, in which shallow and deep aquifers are separated by an aquitard. Pumping from the lower aquifer resulted in a small drawdown in the upper aquifer and a larger drawdown in the aquitard; pumping from the shallow aquifer caused a small drawdown in the aquitard and the deep aquifer. Analysis of pumping test data gives the values of the hydraulic conductivity of the aquitard and the deep aquifer. Long-term observation of groundwater levels in the shallow …
Lewis And Clark And The Geology Of The Great Plains, Robert F. Diffendal, Anne P. Diffendal
Lewis And Clark And The Geology Of The Great Plains, Robert F. Diffendal, Anne P. Diffendal
Papers in Natural Resources
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 (fig. 1). 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 …
Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr.
Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr.
Papers in Natural Resources
Changes in ideas and in technology can come about as slow incremental modifications, as well as by major paradigm shifts. In the case of the development of the ideas of geologic history and time, I will try to present these changes broadly and then look at how some of these have affected interpretation of Nebraska geology. Changes of view on three fronts were important in the development of geologic history and time concepts. First is the question of the nature of time. Is time cyclic or is it linear? The Greco-Oriental cultures had a world view based on cosmic cycles, …
Geology Of The Pre-Dune Strata, James B. Swinehart, R. F. Diffendal Jr.
Geology Of The Pre-Dune Strata, James B. Swinehart, R. F. Diffendal Jr.
Papers in Natural Resources
Over the last 98 million years, four general geological processes have acted to shape the ancient landscapes buried beneath the Sand Hills. Three of these affected the area directly, either depositing sediments on the land surface or eroding it, while a fourth took place west of Nebraska, but affected the region nonetheless.
Shells of clams, oysters, and numerous other kinds of creatures similar to forms that live today in the seas are preserved as fossils in the chalks, limestones, and shales that form the oldest rocks beneath the Sand Hills that will be described. These deposits indicate to geologists that …
New Evidence Supporting The Blancan Age Of The Sand And Gravel Sequence Capping The Ash Hollow Formation, Garden, Keith, And Lincoln Counties, Nebraska, Robert F. Diffendal, James W. Goeke, Michael R. Voorhies
New Evidence Supporting The Blancan Age Of The Sand And Gravel Sequence Capping The Ash Hollow Formation, Garden, Keith, And Lincoln Counties, Nebraska, Robert F. Diffendal, James W. Goeke, Michael R. Voorhies
Papers in Natural Resources
Sandwiched between the overlying eolian Quaternary loesses and sands and the underlying beds of the Ash Hollow Formation, Ogallala Group, buried beneath the sliver of Cheyenne Tableland in Keith County and adjacent areas of western Nebraska, is a mass of fluvially deposited sand, gravelly sand, and sandy gravel of previously uncertain age. Some authors assigned these sediments to the Ogallala Group, while others have called them either the Broadwater Formation (Blancan), or a combination of the two rock units.
The Succession Of Late Cenozoic Volcanic Ashes In The Great Plains: A Progress Report, John Boellstorff
The Succession Of Late Cenozoic Volcanic Ashes In The Great Plains: A Progress Report, John Boellstorff
Papers in Natural Resources
No abstract provided.
Microfossils From The Big Springs Limestone (Pennsylvanian) In Nebraska, Robert F. Diffendal
Microfossils From The Big Springs Limestone (Pennsylvanian) In Nebraska, Robert F. Diffendal
Papers in Natural Resources
Sand-sized residues from partial acetic acid digestion of three samples of the Big Springs Limestone Member of the Lecompton Limestone (Pennsylvanian) from two localities in Cass County, Nebraska, have yielded sixteen genera of microfossils from five major groups of organisms and numerous other whole and partial fossils from seven other groups not identified to the genus level. These fossils include: Protozoa (fusulinids*); Porifera (one spicule type); Bryozoa (two undetermined genera); Brachiopoda (fragments); Gastropoda (two undetermined forms); Ostracoda (Bairdia*, Hollinella*, Moorites*, and one undetermined genus); Crinoidea (whole and partial ossicles*); Echinoidea (whole and partial spines and spine bases*); Holothuroidea (Achistrum …