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Articles 871 - 900 of 1624

Full-Text Articles in Paleontology

Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr. Oct 1993

Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Evidence of the climatic conditions in the mountain sediment source areas for the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska has been sought in an SEM (scanning electron microscope) study of surface features on detrital quartz grains from these deposits. The following lines of indirect evidence raised the possibility of glacial conditions: uplift of up to 3500 m in the source areas, paleohydrologic parameters indicative of a transport system analogous to the modern North Saskatchewan River, and possible cold climate surface features on cobbles from the deposits. SEM analysis shows that five of the nine …


Geology, Geologic Time And Nebraska, Marvin P. Carlson Aug 1993

Geology, Geologic Time And Nebraska, Marvin P. Carlson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Information And Regulations Pertaining To Industrial Minerals In Nebraska, Raymond R. Burchett Jun 1993

Information And Regulations Pertaining To Industrial Minerals In Nebraska, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Lithofacies Of The Pliocene-Pleistocene Lucayan Limestone, Great Abaco Island, Little Bahama Bank, Mary K. Mullen Apr 1993

Lithofacies Of The Pliocene-Pleistocene Lucayan Limestone, Great Abaco Island, Little Bahama Bank, Mary K. Mullen

OES Theses and Dissertations

Petrographic and sedimentologic analyses of eleven shallow subsurface cores (3 to 19 meters in length) from the Lucayan Limestone where it occurs along northeastern Great Abaco Island (little Bahama Bank) are used to delineate five carbonate lithofacies. The most prevalent lithofacies is a mottled, nonskeletal, peloidal packstone to grainstone. Other lithofacies include a rudstone, a laminated nonskeletal grainstone, a crossbedded grainstone and a mudstone-wackestone.

Cementation varies from poor to very well cemented core intervals. Cements observed included equant granular, equant blocky, drusy, meniscus, and needle fiber "whisker" cements. These cements reflect a variety of diagenetic environments such as the vadose, …


Paleobathymetric Interpretation Of Pleistocene Sediments In The South Padre Island Area, Northwestern Gulf Of Mexico, Using Benthic Foraminiferal Morphology, Karen Ianthe Kruebbe-Belwood Apr 1993

Paleobathymetric Interpretation Of Pleistocene Sediments In The South Padre Island Area, Northwestern Gulf Of Mexico, Using Benthic Foraminiferal Morphology, Karen Ianthe Kruebbe-Belwood

OES Theses and Dissertations

This study tested the validity of using intraspecific variation in benthic foraminifera as a means for determining Pleistocene paleobathymetry. Canonical variate analysis was used as a means for determining visually undetectable but statistically significant differences in the morphology of selected species. Two species, Cassidulina subglobosa and Uvigerina peregrina, were collected from Pleistocene well cuttings from the northwest Gulf of Mexico. The canonical analysis involved comparing the intraspecific variation of these Pleistocene species to their counterparts occurring in the modern Gulf of Mexico, where intraspecific variation was previously analyzed and found to be sufficient to allow detection of bathymetric differences …


Paleocene To Miocene Foraminifera From A Well Near Gloucester, Virginia, Nelson Stanley Ford Apr 1993

Paleocene To Miocene Foraminifera From A Well Near Gloucester, Virginia, Nelson Stanley Ford

OES Theses and Dissertations

Lithologic analysis of twenty-one core samples from a well near Gloucester, Virginia, when compared to published descriptions of formations occurring in the study area, indicates the presence of five formations. From oldest to youngest these units are the Aquia (late Paleocene), Nanjemoy (early Eocene), Chickahominy (late Eocene), Old Church (late Oligocene and early Miocene), and Eastover (late Miocene) formations. Comparison of the stratigraphic ranges of key planktic and benthic foraminifera from each of the core samples shows chronological agreement with previously published ages for each of these formations.

Paleoenvironmental analysis of each of the formations in the well is based …


Flat Water: A History Of Nebraska And Its Water, Robert D. Kuzelka, Charles A. Flowerday, Robert N. Manley, Bradley C. Rundquist, Sally J. Herrin Mar 1993

Flat Water: A History Of Nebraska And Its Water, Robert D. Kuzelka, Charles A. Flowerday, Robert N. Manley, Bradley C. Rundquist, Sally J. Herrin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


The Origin And Evolution Of The Southern Snake Range Decollement, East Central Nevada, Allen J. Mcgrew Feb 1993

The Origin And Evolution Of The Southern Snake Range Decollement, East Central Nevada, Allen J. Mcgrew

Department of Earth, Environment and Sustainability Faculty Publications

Regional and local stratigraphic, metamorphic, and structural constraints permit reconstruction of the southern Snake Range extensional deformational system in east central Nevada. The dominant structure of the range, the southern Snake Range décollement (SSRD), operated during Oligocene and Miocene extensional deformation to exhume a footwall of multiply deformed metasedimentary and plutonic rocks. Intrusion of three plutons (∼160 Ma, 79.1 ± 0.5 Ma, and 36 ± 1 Ma, respectively) and development of two cleavages preceded the onset of extensional deformation. Plastic deformation of lower plate metasedimentary rocks accompanied the early phases of regional extension and produced bedding-parallel grain shape foliations and …


Amblyrhiza And The Vertebrate Paleontology Of Anguillean Caves, Donald A. Mcfarlane, Ross D. E. Macphee Jan 1993

Amblyrhiza And The Vertebrate Paleontology Of Anguillean Caves, Donald A. Mcfarlane, Ross D. E. Macphee

WM Keck Science Faculty Papers

Recorded interest in the caves of Anguilla dates back to the second half of the nineteenth century. The earliest explorations were concerned with the locating phosphatic cave earths, and resulted in the mining of several sites. Incidental to this work, the bones of the largest island rodent ever discovered were collected from Aguillan caves. Whereas the phosphate mining operations were short-lived, the remains of the giant rodent Amblyrhiza have catalyzed a continued interest in the caves of Anguilla. The most recent series of explorations have provided the first adequate documentation of Amhlyrhiza fossil sites, and have started to yield radiometric …


Uranium Deposits In Nebraska, R. R. Burchett Jan 1993

Uranium Deposits In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Geology Of Arbor Day Farm Nebraska City, Nebraska, R. R. Burchett Jan 1993

Geology Of Arbor Day Farm Nebraska City, Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-March/April 1993 Jan 1993

Resource News-March/April 1993

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Mineral Operations Review, 1992, R. R. Burchett, Duane A. Eversoll Jan 1993

Nebraska Mineral Operations Review, 1992, R. R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Cedar County Test Hole Logs, Raymond R. Burchett Jan 1993

Cedar County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Cuming County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1993

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

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Geology And Mineral Resources Of Boone, Greeley, Nance, And Wheeler Counties, Nebraska, Raymond R. Burchett Jan 1993

Geology And Mineral Resources Of Boone, Greeley, Nance, And Wheeler Counties, Nebraska, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource Notes-Academic Year 1992-93 Jan 1993

Resource Notes-Academic Year 1992-93

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource News-July/August 1993 Jan 1993

Resource News-July/August 1993

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Niobrara River Basin Geological References, Including Parts Of South Dakota Both In And Outside Of The Basin, Robert F. Diffendal Jr. Jan 1993

Niobrara River Basin Geological References, Including Parts Of South Dakota Both In And Outside Of The Basin, Robert F. Diffendal Jr.

Conservation and Survey Division: Faculty and Staff Publications

Includes Niobrara River Basin geological references, including parts of South Dakota both in and outside of the basin.


Groundwater-Level Changes In Nebraska, 1991, Gregory V. Steele, Perry B. Wigley Oct 1992

Groundwater-Level Changes In Nebraska, 1991, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan Aug 1992

Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Opd Unit of the Pogonip Group is a slope-forming carbonate sequence that crops out in the Arrow Canyon Range 75 miles north of Las Vegas, Nevada. It is composed mainly of grainstones, packstones, and intraformational conglomerates and also contains Calathium-bearing bioherms composed dominantly of wackestones. These rocks were deposited in a shallow-water, high-energy, subtidal, tropical marine environment. Nuia and Nuia-crinoid shoals developed on this shallow ramp and the area was frequently disturbed by storms.

Calathium-dominated carbonate mudmounds emerged on the Nuia and Nuia-crinoid shoals. Although Calathium dominated the mounds on a macroscopic scale, the mounds …


Relation Of Groundwater Fluoride Concentrations To Sediment Mineralogy, Potomac Formation (Cretaceous), Southeastern Virginia, Paul Anthony Maciuika Apr 1992

Relation Of Groundwater Fluoride Concentrations To Sediment Mineralogy, Potomac Formation (Cretaceous), Southeastern Virginia, Paul Anthony Maciuika

OES Theses and Dissertations

Thirty-seven Early cretaceous sediment samples of the Potomac Formation were obtained from four cores to determine if fluoride bearing minerals are responsible for elevated fluoride concentrations in Potomac Formation groundwaters of southeastern Virginia. Investigative methods included total sediment fluoride and particle size analysis, semiquantitative mineralogical analysis (achieved by X-Ray Diffraction) and statistical methods (cluster, canonical and regression analysis). The sediments showed wide variation in textures, ranging from clean sands and gravels to silty clays. Sediment mineralogies were dependent on the prevailing size fraction, with quartz and feldspar dominating the sand and silt fractions, muscovite primarily being found in the silt …


Hydrogeology Of Parts Of The Twin Platte And Middle Republican Natural Resources Districts, Southwestern Nebraska, J. W. Goeke, J. M. Peckenpaugh, R. E. Cady, J. T. Dugan, R. A. Engberg Apr 1992

Hydrogeology Of Parts Of The Twin Platte And Middle Republican Natural Resources Districts, Southwestern Nebraska, J. W. Goeke, J. M. Peckenpaugh, R. E. Cady, J. T. Dugan, R. A. Engberg

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nitrogen And Carbon Isotope Studies Of A Bat Guano Core From Eagle Creek Cave, Arizona, Usa, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya Feb 1992

Nitrogen And Carbon Isotope Studies Of A Bat Guano Core From Eagle Creek Cave, Arizona, Usa, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya

WM Keck Science Faculty Papers

Nitrogen and carbon isotope ratios were studied in a stratified deposit of guano of Mexican Free-tailed bats in Eagle Creek Cave, Arizona, U.S.A. Little diagenetic change was observed over the 25-year time span of the guano deposit. High aridity and reduced circulation of air in the cave are hypothesized to have slowed the normally rapid decomposition of the excreta and the subsequent escape of resultant ammonia. The results suggest the high dependency of the speed of diagenetic change on specific physical and other conditions of the caves and indicate that great care need be exercised in the interpretation of the …


Carbon And Nitrogen Isotopic Signatures Of Bat Guanos As A Record Of Past Environments, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya Feb 1992

Carbon And Nitrogen Isotopic Signatures Of Bat Guanos As A Record Of Past Environments, Hiroshi Mizutani, Donald A. Mcfarlane, Yuko Kabaya

WM Keck Science Faculty Papers

Carbon and nitrogen isotope ratios were measured for various ecogeochemical samples relevant to bat guano ecosystems. In particular, ca. 800-year-old subfossil guano from Jackson's Bay Cave Compex, Jamaica, yielded ratios similar to the modern guano from other Jamaican bat caves but quite different from modern guano of the same area. Diagenetic change and differences in bat food habits were unlikely explanations for the observation. Instead, insects that feed on C4 and CAM plants were the main prey for the bats in present Jackson's Bay area, while the ultimate source of organic matter for bats in other Jamaican caves and for …


The Paleontology And Paleoenvironments Of The Kanawha Black Flint Member And Related Facies, Kanawha Formation (Middle Pennsylvanian), Northwest Boone County And Vicinity, West Virginia, Matthew B. Watson Jan 1992

The Paleontology And Paleoenvironments Of The Kanawha Black Flint Member And Related Facies, Kanawha Formation (Middle Pennsylvanian), Northwest Boone County And Vicinity, West Virginia, Matthew B. Watson

Theses, Dissertations and Capstones

The Kanawha Black Flint member of the Kanawha Formation was deposited in a shallow marine coastal setting with low sand supply and low wave energy. The Kanawha Black Flint member and adjacent coal zones are divisible into five sedimentary facies based on lithology, body and trace fossils and sedimentary structures. Coastal swamps and lakes are represented by thinly laminated carbonaceous shales and coals containing rooted seat rocks and crevasse sandstones with root traces and vertical Calamites trunks.

The offshore facies consists of a gray laminated sideritic shale. Phosphatic and calcareous brachiopods and shallow burrowing bivalves predominate in the offshore assemblage. …


Resource News-May/June 1992 Jan 1992

Resource News-May/June 1992

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Solid Waste Management In Seismic Impact Zones, Raymond R. Burchett Jan 1992

Solid Waste Management In Seismic Impact Zones, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Mineral Operations Review, 1991, R. R. Burchett, Duane A. Eversoll Jan 1992

Nebraska Mineral Operations Review, 1991, R. R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Distribution Of Foraminifera And Pollen In Coastal Depositional Environments Of The Southern Delmarva Peninsula, Virginia, U.S.A., Han Jun Woo Jan 1992

Distribution Of Foraminifera And Pollen In Coastal Depositional Environments Of The Southern Delmarva Peninsula, Virginia, U.S.A., Han Jun Woo

OES Theses and Dissertations

The coastal zone of the southern Delmarva Peninsula exhibits a wide variety of barrier island system subenvironments. This study investigates whether 20 a priori subenvironments can be distinguished from each other on the basis of abiotic environmental variables, pollen assemblages, living foraminiferal populations, and total (living plus dead) foraminiferal assemblages.

The physical data collected from the coastal zone were subjected to canonical variate analysis which discriminated 83% of the stations in 19 groups. These groups were clustered into two internally overlapping sets which represented the inside and outside of the inlet.

Twenty-two pollen types were found in low-energy marsh and …