Earth Sciences Commons^™

Regional Implications Of The Geology Of The Ogallala Group (Upper Tertiary) Of Southwestern Morrill County, Nebraska, And Adjacent Areas, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

A part of a filled Ogallala Group (upper Tertiary) paleovalley system exhumed by recent stream erosion in southwestern Morrill County, Nebraska, and adjacent areas contains steep gradient gullies filled with locally derived sediments. Younger channels filled with granitic gravels derived by stream erosion of the Rocky Mountains to the west and southwest cut across and through these older filled gullies, indicating that there were at least two periods of downcutting followed by periods of filling during the development of this system.

Individual clasts from younger Ogallala gravels are often as large as or larger than clasts from Quaternary gravels transported …

Nebraska Mineral Operations Review, 1982, Raymond R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Permeability, Underpressures, And Convection In The Oceanic Crust Near The Costa Rica Rift, Eastern Equatorial Pacific, Roger N. Anderson, Mark D. Zoback

United States Geological Survey: Staff Publications

In situ permeability and pore pressures were measured 200 m deep beneath the top of the oceanic crust at DSDP site 504B. These measurements have relevance for the transition from convective to conductive heat flow on the south flank of the Costa Rica Rift. Conventional 'slug' and constant rate injection tests were made below a hydraulic packer set at various depths in the hole. The packer was first set in a massive flow unit 37 m below the sediment-basement interface. The bulk permeability of the 172.5m of pillow basalts and basaltic flows below the packer was found to be about …

Thickness And Structure Maps Of The Pennsylvanian And Permian Rocks Across Southern Nebraska, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

The Distribution Of Natural Fractures And Joints At Depth In Crystalline Rock, Donald A. Seeburger, Mark D. Zoback

United States Geological Survey: Staff Publications

This paper presents the results of studies of the natural fracture distribution encountered in 10 test wells drilled in three areas of the United States. Seven of the wells were drilled to depths of 200-250m, while three were drilled to depths of about 1 km. Using an ultrasonic borehole televiewer, fracture depths, strikes, and dips were determined. Steeply dipping fractures were found throughout each of the wells, and in general, few horizontal fractures were observed. Statistically significant fracture pole concentrations were found for each well which were basically invariant with depth, although some variation of fracture orientation with depth was …

Aftershocks Of The Coyote Lake, California, Earthquake Of August 6, 1979' A Detailed Study, P. Reasenberg, W. L. Ellsworth

United States Geological Survey: Staff Publications

Aftershock hypocenters and focal mechanism solutions for the Coyote Lake, California, earthquake reveal a geometrically complex fault structure, consisting of multiples lip surfaces. The faulting surface principally consists of two right stepping en echelon, northwest trending, partially overlapping, nearly vertical sheets and is similar in geometry to a slip surface inferred for the 1966 Parkfield, California, earthquake. The overlap occurs near a prominent bend in the surface trace of the Calaveras fault at San Felipe Lake. Slip during the main rupture, as inferred from the distribution of early aftershocks, appears to have been confined to a 14-km portion of the …

In Situ Study Of The Physical Mechanisms Controlling Induced Seismicity At Monticello Reservoir, South Carolina, Mark D. Zoback, Stephen Hickman

United States Geological Survey: Staff Publications

In two ~1.1-km-deep wells, the magnitudes of the principal in situ stresses, pore pressure, permeability, and the distribution of faults, fractures, and joints were measured directly in the hypocentral zones of earthquakes induced by impoundment of Monticello Reservoir, South Carolina. Analysis of these data suggests that the earthquakes were caused by an increase in subsurface pore pressure sufficiently large to trigger reverse-type fault motion on preexisting fault planes in a zone of relatively large shear stresses near the surface. The measurements indicated (1) near-critical stress differences for reverse-type fault motion at depths less than 200-300 m, (2) possibly increased pore …

Implications Of An Elastic Analysis Of In Situ Stress Measurements Near The San Andreas Fault, A. Mcgarr, M. D. Zoback, T. C. Hanks

United States Geological Survey: Staff Publications

Twenty-nine measurements of in situ stress obtained with the hydraulic fracturing technique near Palmdale, California, are the basis of an elastic analysis of the state of stress in the Mojave Desert adjacent to the San Andreas fault. The measurements were made at depths extending from 80 to 849 m and at distances from the fault between 2 and 34 km. The elastic solution indicates a state of deviatoric stress typical for continents in that the inferred depth gradient of the maximum shear stress is about 7.9 MPa/km. Extrapolation yields an average shear stress in the upper 14 km of the …

Uranium-Series Age Of The Eel Point Terrace, San Clemente Island, California, D. R. Muhs, B. J. Szabo

United States Geological Survey: Staff Publications

Uranium-series analysis of the coral Allopora californica Verrill from the 2nd, 32-m Eel Point terrace on San Clemente Island, California, has yielded an age of 127,000 ± 7,000 yr. The Eel Point terrace is thus correlative with numerous terrace localities on the southern California mainland, with coral reefs on Barbados and New Guinea dated about 120,000 yr, and with substage 5e of the marine oxygen-isotope record. A tectonic uplift rate of about 0.20 m/1,000 yr has been calculated assuming a sea level slightly higher than the present one at the time of terrace formation. Extrapolation of this uplift rate allows …

New Plesiadapiform Primates From The Eocene Of Wyoming And Montana, Kenneth D. Rose, Thomas M. Bown

United States Geological Survey: Staff Publications

Several recently discovered fossil specimens add to our knowledge of plesiadapiform primates.

The Fayum Primate Forest Revisited, Thomas M. Bown, Mary Kraus, Scott Wing, John Fleagle, Bruce H. Tiffney, Elwyn Simons, Carl F. Vondra

United States Geological Survey: Staff Publications

In Oligocene times, the Fayum area of northern Egypt was a subtropical to tropical lowland coastal plain with damp soils and seasonal rainfall that supported an abundance and variety of vegetation, including lianes (large vines), tall trees, and possibly mangroves, and a large and varied vertebrate fauna. The Oligocene marine strandline was close by and principal Jebel Qatrani Formation streams were probably brackish several kilometers inland due to tidal incursions. Sediments of the Jebel Qatrani Formation were deposited by several large meandering streams, associated with minor but sometimes extensive flood basin ponds. These rocks provide no evidence for the former …

Geothermal Resources Of Nebraska, W. D. Gosnold, D. A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Gravity And Ground Magnetic Investigations In Eastern Nebraska, Robert F. Diffendal Jr., R. R. Burchett

Robert F. Diffendal, Jr., Publications

The purpose of this investigation was to extend the area covered by gravity and ground magnetic data related to the Nemaha Uplift and associated structures in eastern Nebraska. Gravity data were collected from Clay, Fillmore, Hamilton, Nuckolls, Polk, Thayer, and York Counties. Additional ground magnetic data and gravity data were collected for central Otoe County.

Regional Tectonics And Seismicity Of Eastern Nebraska, Annual Report, July 1980–June 1981, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

This annual report presents and interprets the information obtained by the Conservation and Survey Division (Nebraska Geological Survey) during contract year July 1, 1980, to June 30, 1981, under contract NRC-04-76-3l5 with the U.S. Nuclear Regulatory Commission. The information pertains to the geology, structure, tectonics, and seismicity of eastern Nebraska with emphasis on central Otoe County. Some of the information presented here results from a combination of studies begun in earlier years but the greater part results from studies begun during the contract year.

The scope of the studies is summarized as follows:

1. Rock outcrops in Otoe County were …

Gravity And Ground Magnetic Investigations In Eastern Nebraska, Robert F. Diffendal Jr., R. R. Burchett

Robert F. Diffendal, Jr., Publications

The purpose of this investigation was to extend the area covered by gravity and ground magnetic data related to the Nemaha Uplift and associated structures in eastern Nebraska. Gravity data were collected from Butler, Jefferson, Saline, and Seward counties. Additional ground magnetic data and gravity data were collected for eastern Sarpy and northeastern Cass counties in Nebraska and gravity data were collected from parts of Mills and Fremont counties in Iowa.

Regional Tectonics And Seismicity Of Eastern Nebraska, Annual Report, July 1979–June 1980, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

This annual report presents and interprets the information obtained by the Conservation and Survey Division (Nebraska Geological Survey) during contract year July 1, 1979, to June 30, 1980, under contract NRC-04-76-3l5 with the U.S. Nuclear Regulatory Commission. The information pertains to the geology, structure, tectonics, and seismicity of eastern Nebraska with emphasis on the vicinity south of Omaha, Nebraska. Some of the information presented here results from a combination of studies begun in earlier years but the greater part results from studies begun during the contract year.

The scope of the studies is summarized as follows:

1. Rock outcrops in …

Groundwater Levels In Nebraska, 1980, Martin S. Johnson, Darryll T. Pederson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nebraska Mineral Operations Review, 1980, D. A. Eversoll, R. R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Nebraska Mineral Operations Review, 1980, Raymonds R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Ice Segregation As An Origin For Lenses Of Non-Glacial Ice In “Ice-Cemented” Rock Glaciers, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

ABSTRACT. In order to flow with the gradients observed (10° to 15°) rock glaciers cannot be simply ice-cemented rock debris, but probably contain masses or lenses of debris-free ice. The nature and origin of the ice in rock glaciers that are in no way connected to ice glaciers has not been adequately explained. Rock glaciers and talus above them are permeable. Water from snow-melt and rain flows through the lower part of the debris on top of the bedrock floor. In the headward part of a rock glacier, where the total thickness is not great, if this groundwater flow is …

Geology And Groundwater Supplies Of Southern Dawes And Northern Sheridan Counties, Nebraska, Vernon L. Souders

Conservation and Survey Division: Faculty and Staff Publications

The upland plain in southern Dawes and northern Sheridan counties of northwest Nebraska is underlain by rocks of Tertiary age. These rocks overlie those of Cretaceous and Jurassic ages in this region of about 2250 square miles . Strata of Tertiary age are a source of groundwater for most of the irrigation, municipal, stock, and rural-domestic needs of the area.

Nine stratigraphic units of Tertiary.age were defined by examination of test hole samples and logs and by examining electric logs of oil and gas tests, driller's logs of irrigation wells, and outcrops. Stratigraphic correlations are difficult in the area because …

Nebraska Groundwater Level (Decline & Rise) And Location Of Registered Wells, 1981

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Late Quaternary Environmental History Of Lake Valencia, Venezuela, J. Platt Bradbury, B. Leyden, M. Salgado-Labouriau, W. M. Lewis Jr., C. Schubert, M. W. Binford, D. G. Frey, D. R. Whitehead, F. H. Weibezahn

United States Geological Survey: Staff Publications

Chemical, paleontological, and mineralogical analyses of a 7.5-meter core from the middle of Lake Valencia, Venezuela, have provided information on the paleoclimatic history of this low-elevation, low-latitude site for the last 13,000 years. The data show that dry climates existed in this region from 13,000 years before present (B.P.) until about 10,000 years B.P. The Lake Valencia Basin was occupied by intermittent saline marshes at that time. About 10,000 years B.P., a permanent lake of fluctuating salinity formed and arboreal plant communities replaced the earlier dominant xeric herbaceous vegetation and marsh plants. By 8500 years B.P., Lake Valencia reached moderate …

A Pleistocene Sand Sea On The Alaskan Arctic Coastal Plain, L. David Carter

United States Geological Survey: Staff Publications

A ridge and thermokarst-basin landscape that is strikingly portrayed in Landsat winter imagery consists of large Pleistocene dunes that have been modified by younger eolian activity and thermokarst processes. This is the most extensive area of large stabilized dunes yet reported in the North American Arctic; the landscape is ofparticular interest because it has been proposed as a$rst-order analog for martian fretted terrain. Recognition of the large dunes permits a new interpretation for linear and curvilinear trends visible in Landsat summer imagery.

Kansan Proglacial Environment, East-Central Nebraska, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

A stream bank along a tributary of Salt Creek in east·central Nebraska displays a sequence of sediments deposited along an eastward flowing stream during part of the approach and subsequent retreat of the last ice sheet to expand into this area during the Kansan glaciation. The section exposes a series of beds of calcareous silt which contain fossil·rich lenses. Sediment characteristics and the habitat requirements of 31 species of snails recovered suggest that the silts accumulated on an aggrading floodplain and probably were derived from erosion of unweathered cal· careous till and calcareous wind·blown silts deposited during an earlier ice …

Annual Outflow Of Water From Nebraska, 1950-1980, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Groundwater Reservoir Management Policy Issue Study: A Contract Report For The State Water Planning And Review Process-Nebraska Natural Resources Commission

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Development Of Irrigation Well Drilling In Nebraska, Vance Anderson

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Climate Of Nebraska, Richard E. Myers

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.

Epa Profile Of Environmental Quality Nebraska, Kathleen Q. Camin

United States Environmental Protection Agency: Publications

Nebraska, Iowa, Kansas, and Missouri, which make up EPA Region VII, are among the leading corn and wheat producing States in the Nation_ These States also produce a significant share of the soybean, grain sorghum, fat cattle, and finished hogs that are supplied to American and foreign markets.

Although the States in Region VII can best be characterized as rural, 65 percent of their nearly 12 million people live in urban areas. In Nebraska, metropolitan areas such as Omaha 4 have environmental problems resulting from major industrial operations, municipal services, transportation, and energy production. Metropolitan areas, however, do not have …