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Articles 3541 - 3570 of 4538

Full-Text Articles in Earth Sciences

Sedimentary Paleoenvironments Of Fossil Platyrrhine Localities, Miocene Pinturas Formation, Santa Cruz Province, Argentina, Thomas Bown, Claudio N. Larriestra Jan 1990

Sedimentary Paleoenvironments Of Fossil Platyrrhine Localities, Miocene Pinturas Formation, Santa Cruz Province, Argentina, Thomas Bown, Claudio N. Larriestra

United States Geological Survey: Staff Publications

The Pinturas Formation is a pyroclastic and epiclastic aeolian deposit of Miocene age lying discordantly upon Jurassic rocks in the elevated Andean precordillera of northwest Santa Cruz Province, Argentina. The history of de\'elopment of the Pinturas Formation was significantly affected by the gradual, though sporadic, draping of this aeolian sediment across a profound, slowly filling paleotopography. The Pinturas depositional cycle consisted of: (1) minor aeolian deposition followed by soil formation, and (2) major aeolian deposition followed by intervals of regional erosion. Fluvial action seems to have been almost wholly confined to intraformational erosion, and two significant intraformational erosional unconformities divide …


Phytoplankton Dynamics In Three Rocky Mountain Lakes, Colorado, U.S.A., Diane M. Mcknight, Richard L. Smith, J. Platt Bradbury, Jill S. Baron, Sarah Spaulding Jan 1990

Phytoplankton Dynamics In Three Rocky Mountain Lakes, Colorado, U.S.A., Diane M. Mcknight, Richard L. Smith, J. Platt Bradbury, Jill S. Baron, Sarah Spaulding

United States Geological Survey: Staff Publications

In 1984 and 1985 seasonal changes in phytoplankton were studied in a system of three lakes in Loch Vale, Rocky Mountain National Park, Colorado. Three periods were evident: (1) A spring bloom, during snowmelt, of the planktonic diatom Asterionella Formosa, (2) a mid- summer period of minimal algal abundance, and (3) a fall bloom of the blue-green alga Oscillatoria limnetica. Seasonal phytoplankton dynamics in these lakes are controlled partially by the rapid flushing rate during snowmelt and the transport of phytoplankton from the highest lake to the lower lakes by the stream, Icy Brook. During snowmelt, the A. …


Crustal Strain Near The Big Bend Of The San Andreas Fault: Analysis Of The Los Padres-Tehachapi Trilateration Networks, California, Donna Eberhart-Phillips, Michael Lisowski, Mark D. Zoback Jan 1990

Crustal Strain Near The Big Bend Of The San Andreas Fault: Analysis Of The Los Padres-Tehachapi Trilateration Networks, California, Donna Eberhart-Phillips, Michael Lisowski, Mark D. Zoback

United States Geological Survey: Staff Publications

In the region of the Los Padres-Tehachapi geodetic network, the San Andreas fault (SAF) changes its orientation by over 30 ° from N40 °W, close to that predicted by plate motion for a transform boundary, to N73 °W. The strain orientation near the SAF is consistent with right-lateral shear along the fault, with maximum shear rate of 0.38 ± 0.01 μrad/yr at N63 °W. In contrast, away from the SAF the strain orientations on both sides of the fault are consistent with the plate motion direction, with maximum shear rate of 0.19 ± 0.01 μrad/yr at N44 °W. The strain …


Age Estimates And Uplift Rates For Late Pleistocene Marine Terraces' Southern Oregon Portion Of The Cascadia Forearc, Daniel R. Muhs, Harvey M. Kelsey, Gifford H. Miller, Geoge L. Kennedy, Joseph F. Whelan, Galan W. Mcinelly Jan 1990

Age Estimates And Uplift Rates For Late Pleistocene Marine Terraces' Southern Oregon Portion Of The Cascadia Forearc, Daniel R. Muhs, Harvey M. Kelsey, Gifford H. Miller, Geoge L. Kennedy, Joseph F. Whelan, Galan W. Mcinelly

United States Geological Survey: Staff Publications

Marine terraces are prominent landforms along the southern Oregon coast, which forms part of the forearc region of the Cascadia subduction zone. Interest in the Cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes. In addition, other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates. With these hypotheses in mind, we generated new uranium series, amino acid, and stable isotope data for southern Oregon marine terrace fossils. These data, along with terrace elevations and …


Drying Out Wet Basements, Mark S. Kuzila Jan 1990

Drying Out Wet Basements, Mark S. Kuzila

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Annual Departures From Average Annual Precipitation In Nebraska, 1850-1989, Conservation Survey Division Jan 1990

Annual Departures From Average Annual Precipitation In Nebraska, 1850-1989, Conservation Survey Division

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 1989)/Registered Irrigation Wells In Nebraska (As Of January 1, 1990), Mark Burbach Jan 1990

Significant Rises And Declines In Nebraska Groundwater Levels (From Pre-Development As Of Fall 1989)/Registered Irrigation Wells In Nebraska (As Of January 1, 1990), Mark Burbach

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 1988) /Registered Irrigation Wells In Nebraska (As Of January 1, 1989), Conservation Survey Division Jan 1990

Significant Rises And Declines In Nebraska Groundwater Levels (From Pre-Development As Of Fall 1988) /Registered Irrigation Wells In Nebraska (As Of January 1, 1989), Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Mineral Operations Review, 1989, Raymond R. Burchett, Duane A. Eversoll Jan 1990

Nebraska Mineral Operations Review, 1989, Raymond R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource Notes-Academic Year 1989-90 Jan 1990

Resource Notes-Academic Year 1989-90

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


The Permian System In Nebraska, R. R. Burchett Jan 1990

The Permian System In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Potash Deposits In Nebraska, R. R. Burchett Jan 1990

Potash Deposits In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Quartzite Deposits In Nebraska, R. R. Burchett Jan 1990

Quartzite Deposits In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Salt Deposits In Nebraska, R. R. Burchett Jan 1990

Salt Deposits In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Sand And Gravel Deposits In Nebraska, R. R. Burchett Jan 1990

Sand And Gravel Deposits In Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Sandstone Deposits In Nebraska, R. R. Burchett Jan 1990

Sandstone Deposits In Nebraska, R. R. Burchett

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 1989)/Registered Irrigation Wells In Nebraska (As Of January 1, 1990), Mark Burbach Jan 1990

Significant Rises And Declines In Nebraska Groundwater Levels (From Pre-Development As Of Fall 1989)/Registered Irrigation Wells In Nebraska (As Of January 1, 1990), Mark Burbach

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Water Quality In The Lower Platte River Basin With Emphasis On Agrichemicals, R. R. Spalding Jan 1990

Water Quality In The Lower Platte River Basin With Emphasis On Agrichemicals, R. R. Spalding

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


35th Annual Midwest Groundwater Conference Program With Abstracts, P. B. Wigley, K. E. Stork, D. C. Gosselin Jan 1990

35th Annual Midwest Groundwater Conference Program With Abstracts, P. B. Wigley, K. E. Stork, D. C. Gosselin

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Mineral Facts For Nebraska, Raymond R. Burchett Jan 1990

Mineral Facts For Nebraska, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


The Fourth Of July Depends Upon Minerals, R. R. Burchett Jan 1990

The Fourth Of July Depends Upon Minerals, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Dehydration Tolerance Of Several Populus Deltoides Clones, G. Michael Gebre Dec 1989

Dehydration Tolerance Of Several Populus Deltoides Clones, G. Michael Gebre

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

No abstract provided.


Reproductive Biology Of Pinus Sylvestris L.: Seed Yield, Flower Phenology, The Response Of Young Seedlings To Ga 4/7, And Developmental Anatomy, Teresa K. Boes Dec 1989

Reproductive Biology Of Pinus Sylvestris L.: Seed Yield, Flower Phenology, The Response Of Young Seedlings To Ga 4/7, And Developmental Anatomy, Teresa K. Boes

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

No abstract provided.


A Revision Of The North American Papillose Allocreadiidae (Digenea) With Independent Cladistic Analyses Of Larval And Adult Forms, Janine N. Caira Oct 1989

A Revision Of The North American Papillose Allocreadiidae (Digenea) With Independent Cladistic Analyses Of Larval And Adult Forms, Janine N. Caira

Bulletin of the University of Nebraska State Museum (1924–2023)

Adult specimens of all 19 North American species of papillose allocreadiids were examined. A description and figure is given for the adult of each species; details of the cirrus sacs are presented for most spesies for the first time. Descriptions were emended where necessary and judgments were made on synonymies. Scanning electron micrographs of the oral sucker of 10 species are presented as is a new key to the 19 species. A cladistic analysis was performed on the group based on adult characters. The analysis indicated that the group is monophyletic on the basis of the ventral papillae associated with …


Groundwater Levels In Nebraska, 1988, Michael J. Ellis, Gregory V. Steele, Perry B. Wigley Oct 1989

Groundwater Levels In Nebraska, 1988, Michael J. Ellis, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Habitat Use And Diet Analysis Of Breeding Common Barn Owls In Western Nebraska, Joseph A. Gubanyi M.S. Apr 1989

Habitat Use And Diet Analysis Of Breeding Common Barn Owls In Western Nebraska, Joseph A. Gubanyi M.S.

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

I studied barn owl (Tyto alba) breeding biology in western Nebraska 1984-1986. I had greatest success capturing males (56% success) at night using trap doors at nest sites and females (91 % success) using hoop nets at nest sites during the day. Barn owls removed 16 of 23 tail-mounted radios. Eight birds were radio-tracked for 7-14.5 hours. The mean foraging range was 198 ha (32- 299 ha, n = 8) with < 1 % overlap among birds from adjacent nest sites. Field-tested telemetry error was high (mean displacements of radio-locations for 2 birds were 208 and 241 m). I found no relationship between percent cover in foraging habitat and reproductive success. I identified 10,140 prey items from 15 nest sites and found both annual and seasonal variation in barn owl diets. Microtus ochrogaster occurred most frequently (32.7%) and increased in the diet from 17.6 to 27.2 to 43.5% 1984-1986. M. ochrogaster and Perognathus hispidus annual frequencies were …


The Style Of Late Cenozoic Deformation At The Eastern Front Of The California Coast Ranges, Carl M. Wentworth, Mark D. Zoback Apr 1989

The Style Of Late Cenozoic Deformation At The Eastern Front Of The California Coast Ranges, Carl M. Wentworth, Mark D. Zoback

United States Geological Survey: Staff Publications

The 1983 Coalinga earthquake occurred at the eastern boundary of the California Coast Ranges in response to northeast directed thrusting. Such movements over the past 2 Ma have produced Coalinga anticline by folding above the blind eastern tip of the Coalinga thrust zone. The 600-km length of the Coast Ranges boundary shares a common structural setting that involves westward upturn of Cenozoic and Cretaceou strata at the eastern front of the Coast Ranges and a major, southwest facing step in the basement surface beneath the western Great Valley. Like Coalinga anticline, Pliocene and Quaternary folding and faulting along the rest …


Geology Of The Pre-Dune Strata, James B. Swinehart, Robert F. Diffendal Jr. Jan 1989

Geology Of The Pre-Dune Strata, James B. Swinehart, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

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 …


Late Pennsylvanian And Early Permian Cyclic Sedimentation, Paleogeography, Paleoecology, And Biostratigraphy In Kansas And Nebraska, Roger K. Pabian, Robert F. Diffendal, Jr. Jr. Jan 1989

Late Pennsylvanian And Early Permian Cyclic Sedimentation, Paleogeography, Paleoecology, And Biostratigraphy In Kansas And Nebraska, Roger K. Pabian, Robert F. Diffendal, Jr. Jr.

Robert F. Diffendal, Jr., Publications

Overview of Upper Pennsylvanian Cyclic Sedimentation in Kansas and Nebraska, Philip H. Heckel, Department of Geology, University of Iowa, Iowa City, Iowa

With contributions from:

Christopher G. Maples and W. Lynn Watney, Kansas Geological Survey, Lawrence, Kansas

John Harris, Shell Western Exploration and Production, Inc., Houston, Texas

David Ball, Champlin Petroleum Company, Houston, Texas

Philip H. Heckel, University of Iowa, Iowa City, Iowa

R. R. West, V. Voegeli, S. Roth, K. Leonard, H. R. Feldman, and C. Cunningham, Kansas State University, Manhattan, Kansas

Royal H. Mapes, Ohio University, Athens, Ohio

Hans-Peter Schultze, University of Kansas, Lawrence, Kansas

R. Matt Joeckel, …


Lake Maloney Quadrangle, Nebraska--Lincoln County, 7.5 Minute Series (Topographic), Robert F. Diffendal Jr. Jan 1989

Lake Maloney Quadrangle, Nebraska--Lincoln County, 7.5 Minute Series (Topographic), Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

7.5 minute series (topographic)

100° 45' to 100° 52' 30"

41° 00' to 41° 07' 30"

Includes Ogallala Outcrops (pencil)