Earth Sciences Commons^™

Pliocene-Pleistocene Variations In Aragonite Content And Planktonic Oxygen-Isotope Record In Bahamian Periplatform Ooze, Hole 633a, André W. Droxler, Christopher H. Bruce, William W. Sager, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

Hole 633A was drilled in the southern part of Exuma Sound on the toe-of-slope of the southeastern part of Great Bahama Bank during ODP Leg 101. The top 55 m, collected as a suite of six approximately 9.5-m-long hydraulic piston cores, represents a Pliocene-Pleistocene sequence of periplatform carbonate ooze, a mixture of pelagic calcite (foraminifer and coccolith tests), some pelagic aragonite (pteropod tests), and bank-derived fine aragonite and magnesian calcite. A 1.6-m.y.-long hiatus was identified at 43.75 mbsf using calcareous nannofossil biostratigraphy and magnetostratigraphy.

The 43.75-m-thick periplatform sequence above the hiatus is a complete late Pliocene-Quaternary record of the past …

Oligocene Calcareous-Nannofossil Biostratigraphy From Leg 101, Site 628, Little Bahama Bank Slope, Michael J. Moran, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

Drilling at Hole 628A, Leg 101 of the Ocean Drilling Program, recovered a thick, relatively complete Oligocene section of nannofossil-foraminifer chalk and ooze. Sediments from Cores 101-628A-16H through 101-628A-29X were examined using the light microscope to provide information about biostratigraphy of calcareous nannofossils. Several authors noted a problem in distinguishing the first appearance of species within the Sphenolithus predistentus-S. ciperoensis lineage of the mid-Oligocene, particularly Sphenolithus ciperoensis, because of the gradual evolution of its members. Successful separation of species in this lineage is critical for accurately dating relative age of mid- and upper-Oligocene nannofossil sediments. Length and taper of …

The Onset Of Spring Melt In First-Year Ice Regions Of The Arctic As Determined From Scanning Multichannel Microwave Radiometer Data For 1979 And 1980, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

Sea ice ablation is an important physical process affecting the global climate system. During the Arctic melt season, rapid changes occur in both sea ice surface conditions and the extent of ice. These changes alter the albedo and vary the surface energy budget. Understanding variations in Arctic sea ice is critical for global climate studies. This paper investigates the spring onset of melt in the Arctic seasonal sea ice zone through analysis of melt signatures derived from Nimbus 7 scanning multichannel microwave radiometer data. Satellite-derived melt signatures, determined by 18- and 37-GHz vertical brightness temperatures, are associated with the initial …

Fox Squirrel Interaction With Electrical Transformers, J. Christopher Hamilton

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

No abstract provided.

Fox Squirrel Interaction With Electrical Transformers, J. Christipher Hamilton

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

No abstract provided.

Neogene And Quaternary Lacustrine Diatom Biochronology, Western Usa, William Krebs, J. Platt Bradbury, Edward Theriot

United States Geological Survey: Staff Publications

Neogene and Quaternary lacustrine diatomaceous deposits are numerous in the western United States, particularly in the Great Basin. Some of these sediments are interbedded with volcanic rocks that have been dated radiometrically or by the fssion track method. Fossil lacustrine diatom floras can thus be arranged in geochronological order. By this means, a biochronological pattern of lacustrine diatom evolution has emerged: obligate nonmarine Actinocyclus Ehrenberg (Family Hemidiscaceae) appeared in the early Miocene and attained maximum diversity in the middle middle Miocene. A single species of non-marine Actinocyclus persisted to the end of the middle Miocene. Only two species of marine …

A Preliminary Study Of The Hydrogeology Of The Dakota Formation In Douglas, Sarpy And Washington Counties, Eastern Nebraska, Thomas Mark O'Connor

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

This study provides preliminary information on the hydrogeology of the Dakota Formation within a 1,000 square-mile area in eastern Nebraska. Isopach maps of the Dakota Formation and individual sand and gravel beds were constructed using a computer contouring program. Hydraulic conductivity values for water-bearing sand beds in the Dakota were estimated using the equation for calculating the specific capacity of wells and results from a grain-size analysis. Concentrations of major dissolved species were determined for samples collected from twenty five wells. The Dakota Formation is characterized by an increase in thickkness and an increase in percentage of clay versus sand …

A Field Test Of Habitat Evaluation Procedures For Creek Chub (Semotilus Atromaculatus) And Channel Catfish (Ictalurus Punctatus), Donald W. Zaroban

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

No abstract provided.

A Preliminary Study Of The Hydrogeology Of The Dakota Formation In Douglas, Sarpy And Washington Counties, Eastern Nebraska, Thomas Mark O'Connor

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

This study provides preliminary information on the hydrogeology of the Dakota Formation within a 1,000 square-mile area in eastern Nebraska. Isopach maps of the Dakota Formation and individual sand and gravel beds were constructed using a computer contouring program. Hydraulic conductivity values for water-bearing sand beds in the Dakota were estimated using the equation for calculating the specific capacity of wells and results from a grain-size analysis. Concentrations of major dissolved species were determined for samples collected from twenty five wells. The Dakota Formation is characterized by an increase in thickkness and an increase in percentage of clay versus sand …

Snow Melt On Sea Ice Surfaces As Determined From Passive Microwave Satellite Data, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

SMMR data for the year 1979, 1980 and 1984 have been analyzed to determine the variability in the onset of melt for the Arctic seasonal sea ice zone. The results show melt commencing in either the Kara/Barents Seas or Chukchi Sea and progressing zonally towards the central Asian coast (Laptev Sea). Individual regions had interannual variations in melt onset in the 10-20 day range. To determine whether daily changes occur in the sea ice surface melt, the SMMR 18 and 37 GHz brightness temperature data are analyzed at day/night/twilight periods. Brightness temperatures illustrate diurnal variations in most regions during melt. …

Groundwater Levels In Nebraska, 1986, Michael J. Ellis, Vincent H. Dreeszen

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Geology Of Selected Sites Near The Republican River In Franklin County, Nebraska, Roger K. Pabian

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Effect Of Shelterbelts On Growth, Yield, And Quality Of Alfalfa (Medicago Sativa L.), Thomas G. Hans

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

No abstract provided.

Prairie Dog Population Growth: Relationships To Population Density, Habitat, And Livestock Grazing Management, Kelly A. Cable

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

No abstract provided.

Effects Of Sediment Addition On The Drift Of Aquatic Macroinvertebrates In Nine Mile Creek, Nebraska, Laurence Angle

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

No abstract provided.

Diatoms And Tonsteins As Paleoenvironrnental And Paleodepositional Indicators In A Miocene Coal Bed, Costa Rica, J. David Sanchez, J. Platt Bradbury, Bruce F. Bohor, Donald A. Coates

United States Geological Survey: Staff Publications

Fresh-water diatoms are present in coal, and tonsteins (altered volcanic ash) are interbedded with the coal, in the Miocene Venado Formation on the southwest margin of the Limon Basin, in Provincia Alajuela, northern Costa Rica. The Venado Formation is composed of more than 300 m of mudstone, siltstone, sandstone, limestone, volcaniclastics, and coal beds. The coal beds are of unknown lateral extent and mainly occur in the middle part of the formation. The Pataste coal bed occurs near the middle of the formation and is divided into three parts by two tonstein layers. The abundance of biogenic opaline material (diatoms) …

A Test Of Habitat Evaluation Models Using Avian Densities, Jeremy B. Cable

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

No abstract provided.

Duer Ranch, Morrill County, Nebraska: Contrast Between Cenozoic Fluvial And Eolian Deposition, James B. Swinehart, R. F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Duer Ranch locality contains some of the finest and most easily accessible examples of different styles of alluvial cuts and fills in the Cenozoic rocks of Nebraska. It offers a unique area in which to examine the geometries and alluvial fills of several Miocene and Pliocene age paleovalleys and paleo-gullies. Good exposures of eolian volcaniclastic siltstones and a regionally important volcanic ash of the Oligocene age Brule Formation are also present at the Duer Ranch locality. In addition, Quaternary ephemeral stream development and deposits can be studied.

Location and Accessibility

Significance of the Locality

Locality Information

Measured Sections [I-IV] …

Paleohydrology Of Some Ogallala (Neogene) Streams In The Southern Panhandle Of Nebraska, R. G. Goodwin, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Stratification and estimated paleoflow conditions for valley-fill deposits suggest that Ogallala Group streams in western Nebraska were similar to modern streams of south-central Alberta.

Ogallala stratification includes medium-scale (0.5 to 2.0 m thick) trough crossbedded sand and gravel, tabular indistinctly horizontally bedded and imbricated gravel, and horizontally bedded sand and pebbly sand. Valley fills are 15 to 55 m thick and 800 to 1800 m wide at the top. Some are in bedrock-floored channels resembling the “inner channels” of Shepherd and Schumm (1974).

Gradients for three well exposed paleovalley floors range from 0.0014 to 0.0020 (m/m) after tectonic correction. This …

Baseline Acidity Of Percipitation At The South Pole During The Last Two Millennia, J H. Cragin, M B. Giovinetto, A J. Gow

United States Army: Publications

Measurements of meltwater pH from annual layers of South Pole firn and ice samples ranging in age from 40 to 2000 years B .P. show that precipitation at this remote site has a higher natural acidity than that expected from atmospheric equilibrium with CO2. The average pH of deaerated (C O2-free)samples was 5 .64 + 0.08, while a irequilibrated samples averaged5 .37 + 0.08, a pH that is about a factor of two more acidic than the expected background pH of 5.65. The observed" excess" acidity can be accounted for by SO1-and NO7 levels in the samples originating from non-anthropogenic …

Isotope Content And Temperature Of Precipitation In Southern Nevada, August 1983-August 1986, W. K. Milne, Larry Benson, P. W. Mckinley

United States Geological Survey: Publications

From August 1983 through August 1986, 429 precipitation samples of 112 precipitation events were collected at 12 stations in southern Nevada. Some of these samples were analyzed for oxygen-18, deuterium, and tritium. The results of these analyses as well as the air temperature and the precipitation measured at the collection sites are tabulated in this report. The sampling program provides a data base for future interpretive studies on the timing and origin of ground-water recharge in the Yucca Mountain region, of southern Nevada.

The stable-isotope composition of precipitation is the result of fractionation processes that occur in the atmosphere. Isotopic …

Integration Of Channel And Floodplain Suites, Developmental Sequence And Lateral Relations Of Alluvial Paleosols, Thomas M. Bown, Mary J. Krause

United States Geological Survey: Staff Publications

The lower Eocene Willwood Formation of the Bighorn Basin, northwest Wyoming, consists of about 770 m of alluvial rocks that exhibit extensive mechanical and geochemical modifications resulting from Eocene pedogenesis. Willwood paleosols vary considerably in their relative degrees of maturity; maturity is defined as stage of development as a function of the amount of time required to form. Five arbitrary stages are proposed to distinguish these soils of different maturities in the Willwood Formation. Stage 1 soils, the least mature, are entisols; stage 2 and stage 3 soils are intermediate in maturity and are probably alfisols; and stage 4 and …

45. Clay Mineralogy Of The Lower Cretaceous Deep-Sea Fan, Deep Sea Drilling Project Site 603, Lower Continental Rise Off North Carolina, Mary Anne Holmes

Department of Earth and Atmospheric Sciences: Faculty Publications

The clay mineralogy of Lower Cretaceous deep-sea fan sediment in the western North Atlantic is dominated by smectite in most intervals, and by illite in samples from intervals of high sand input. Different intervals of high sand input are enriched in kaolinite. Kaolinite and illite levels do not correlate in this sediment, indicating that the input of each clay type was independent and represents either a different provenance or a different depositional mode. The latter hypothesis is preferred because equivalent, continental strata have clay mineral suites dominated in most cases by kaolinite, and in other cases by illite. Only marine …

Evolution Of The Aeluroid Camivora: Significance Of Auditory Structure In The Nimravid Cat Dinictis, Robert M. Hunt Jr.

Department of Earth and Atmospheric Sciences: Faculty Publications

Evolutionary lineages among living and extinct Carnivora can be identified by a diagnostic pattern of ontogenetic elements forming the auditory bulla enclosing the middle ear, best observed in newborn and juvenile animals. However, in the fossil record, the delicate unfused bulla parts of very young carnivorans are rarely preserved. Thus bulla composition in extinct lineages is difficult to determine unless juveniles with well-preserved auditory bullae can be found. Discovery in 1981 of an intact cranium of a juvenile aeluroid carnivoran (Dinictis) from the White River Group (Oligocene) in northwestern Nebraska has resulted in an improved understanding of bulla …

Late Cenozoic Geology Along The Summit To Museum Hiking Trail, Scotts Bluff National Monument, Western Nebraska, J. B. Swinehart, D. B. Loope

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

A Hydrogeologic Study Of The Local Groundwater Flow System At Osmond, Ne, Jonathan Alix

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Resource Notes-Fall/Winter 1986-87

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Significant Rises And Declines In Nebraska Groundwater Levels (From Pre-Development As Of Fall 1985)/Registered Irrigation Wells In Nebraska (As Of January 1, 1986), Conservation Survey Division, U.S. Geological Survey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

34. Provenance And Deposition Of Lower Cretaceous Turbidite Sands At Deep Sea Drilling Project Site 603, Lower Continental Rise Off North Carolina, Mary Anne Holmes, James Breza, Sherwood Wise

Department of Earth and Atmospheric Sciences: Faculty Publications

During the drilling of Hole 603B on Deep Sea Drilling Project Leg 93, an unexpected series of sand-, silt-, and claystone turbidites was encountered from Cores 603B-45 through -76 (1224-1512 m sub-bottom depth). Complete and truncated Bouma sequences were observed, some indicating deposition by debris flows. Sand emplacement culminated with the deposition of a 30-m-thick, unconsolidated sand unit (Cores 603B-48 through -45).
The purpose of this preliminary study is to determine the nature of the heavy mineral suites of this sediment in order to make tentative correlations with onshore equivalents. The heavy mineralogy of Lower Cretaceous North American mid-Atlantic coastal …

Resource Notes-Spring/Summer 1987

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.