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Articles 26491 - 26520 of 29719

Full-Text Articles in Physical Sciences and Mathematics

Wheeler County Test Hole Logs, Raymond R. Burchett Jan 1992

Wheeler County Test Hole Logs, Raymond R. Burchett

Conservation and Survey Division

No abstract provided.


Groundwater-Level Changes In Nebraska, Predevelopment To Fall 1992, Conservation Survey Division, U.S. Geological Survey Jan 1992

Groundwater-Level Changes In Nebraska, Predevelopment To Fall 1992, Conservation Survey Division, U.S. Geological Survey

Conservation and Survey Division

No abstract provided.


A Geographical Analysis Of Aquaculture Sites In Puget Sound, Dennis R. Gillespie Jan 1992

A Geographical Analysis Of Aquaculture Sites In Puget Sound, Dennis R. Gillespie

WWU Graduate School Collection

Attempts to promote aquaculture in Puget Sound waters have met with heated debate over the physical and environmental impacts such siting would produce. These are concerns that aquaculturists contend are nothing more than smoke screens used to conceal the only issues that matter to their opponents — aesthetic appearance and the potential threat to property values.

This essay examines the issues concerning aquaculture in the region. First the history of aquaculture in the Sound from the turn of the century through to the present is addressed. Highlighted are the problems of stewardship and the challenges faced by the industry in …


Late Pleistocene Deglaciation History At Point Partridge, Central Whidbey Island, Washington, Cynthia A. Carlstad Jan 1992

Late Pleistocene Deglaciation History At Point Partridge, Central Whidbey Island, Washington, Cynthia A. Carlstad

WWU Graduate School Collection

The study area contains a record of deglaciation events that has not been recognized elsewhere in the Puget Lowland. This record includes both subaerial outwash and glaciomarine deposition. The geologic history of the study area during recession of the Vashon ice sheet is marked by the following events:

  1. Deposition of a kame delta complex from grounded ice probably located in Penn Cove and west of Point Partridge. This delta complex was built into marine water with a sea-level at approximately 55 meters. Eventually, ice drained by the outwash streams stagnated in the Point Partridge kettle region.
  2. Isostatic rebound of the …


Metamorphism And Plutonism Of The Mt. Buckindy – Snowking Region, North Cascades, Washington, Steve M. (Steven Milton) Fluke Jan 1992

Metamorphism And Plutonism Of The Mt. Buckindy – Snowking Region, North Cascades, Washington, Steve M. (Steven Milton) Fluke

WWU Graduate School Collection

The focus of this study is on the metamorphism, plutonism, and structures of the Mt. Buckindy-Snowking region of the North Cascades crystalline core.

In a 15 by 30 km region in the northwest portion of the crystalline core, Cretaceous plutons in a northwest-southeast belt intrude rocks of the Napeequa unit. Metamorphic grade in the country rock ranges from lower greenschist facies in the northwest to amphibolite facies in the southeast. Thermobarometry applied to the equilibrium assemblages garnet-biotite-muscovite-plagioclase and garnet-homblende- plagioclase defines orogen-normal isobars varying from less than 4 Kb in the northwest to over 9 Kb in the south.

Plutons …


Paleomagnetism And Tectonics Of The Crescent Formation Northern Olympic Mountains, Washington, Andrew C. (Andrew Clyde) Warnock Jan 1992

Paleomagnetism And Tectonics Of The Crescent Formation Northern Olympic Mountains, Washington, Andrew C. (Andrew Clyde) Warnock

WWU Graduate School Collection

Use of a small-diameter core drill has allowed the paleomagnetic sampling of the rims of fractured pillow basalts of the lower Crescent Formation in the northern Olympic Mountains. The pillows selected have spherical or oblate morphologies which typically develop on horizontal or mildly-dipping surfaces. Pillow keel structures and sedimentary interbeds were used to obtain bedding attitudes and top directions for use in structural corrections. All specimens were subjected to progressive thermal demagnetization. After removal of a low blocking-temperature recent overprint, stable endpoints were reached by 580°C in 11 of the 33 sites sampled (large within-site scatter was commonly observed in …


Petrology And Structure Of The Eldorado Peak Area, North Cascades, Washington, Dan (Daniel Phelan) Mcshane Jan 1992

Petrology And Structure Of The Eldorado Peak Area, North Cascades, Washington, Dan (Daniel Phelan) Mcshane

WWU Graduate School Collection

In this thesis the problem of the timing and mechanism of orogeny in the Skagit Gneiss of the North Cascades, Washington, is addressed by investigating plutonism and metamorphism in the vicinity of Eldorado Peak.

The primary finding of this project is that the 88-90 Ma Eldorado pluton was intruded, not faulted, into the Cascade River Schist and Skagit Gneiss. Intrusion is indicated by cross-cutting of foliations in country rock by the pluton, apophyses of Eldorado pluton in the country rock, and xenoliths of local country rock in the pluton. Detailed mapping shows that the Eldorado pluton does not cross-cut younger …


Development Of Organic Mud Mounds In A Mixed Carbonate-Siliciclastic Depositional Environment, John M. Ryan, Doy L. Zachry Jan 1992

Development Of Organic Mud Mounds In A Mixed Carbonate-Siliciclastic Depositional Environment, John M. Ryan, Doy L. Zachry

Journal of the Arkansas Academy of Science

Organic carbonate mud mounds in the Prairie Grove Member of the Hale Formation developed on a shallow shelf swept by competent tidal currents. The mounds were stabilized by crustose red algae and fostered a sheltered setting where phylloid algae and marine invertebrates could thrive. The mounds supplied skeletal sediment locally to the intermound areas as well as regionally along the stable platform. This sediment mixed with quartz sand to form a major mixed carbonate-siliciclastic system in northwestern Arkansas.


Natural And Technological Disasters: Causes, Effects And Preventive Measures, Nazrul I. Khandaker Jan 1992

Natural And Technological Disasters: Causes, Effects And Preventive Measures, Nazrul I. Khandaker

Publications and Research

No abstract provided.


Mineralogy, Geochemistry, And Dispersal Of Opaque Oxides On The Continental Shelf Of The Cascadia Margin, Kommajosyula Subramanya Ravi Jan 1992

Mineralogy, Geochemistry, And Dispersal Of Opaque Oxides On The Continental Shelf Of The Cascadia Margin, Kommajosyula Subramanya Ravi

Dissertations and Theses

Opaque oxide minerals (ilmenite, chromite, and magnetite) in sands from the Oregon continental shelf have been studied to establish the provenance, dispersal, and grade of potential shelf placer deposits. The study area extends southward from offshore of the Columbia River in northern Oregon to the Klamath River in northern California.


Stratigraphy And Structure Of The Southeast Part Of The Portland Basin, Oregon, Kenneth E. Lite Jr. Jan 1992

Stratigraphy And Structure Of The Southeast Part Of The Portland Basin, Oregon, Kenneth E. Lite Jr.

Dissertations and Theses

The southeast part of the Portland Basin has been previously described by other investigators. However, little detailed information existed on the depositional relationships between the units, the various sedimentary fades, or the origin of many of the units.


Regional Tectonic Deformation Of The Northern Oregon Coast As Recorded By Pleistocene Marine Terraces, Richard Alan Mulder Jan 1992

Regional Tectonic Deformation Of The Northern Oregon Coast As Recorded By Pleistocene Marine Terraces, Richard Alan Mulder

Dissertations and Theses

Pleistocene marine terraces of the northern Oregon coast are an important factor in understanding the tectonics and paleoseismicity of the central Cascadia subduction zone. The lowest marine terrace, tentatively correlated to 80,000 year old Whiskey Run terrace of southern Oregon, is intermittently exposed in the present day sea cliff along an 80 km section of coastline between Tillamook Head and Cape Kiwanda. Terrace sediments consist largely of fine material such as clay, silt and fine sand with several locations containing large amounts of gravel derived from nearby headlands and steep bedrock hills. The terrace sediments are interpreted to be deposited …


Metamorphic Petrology And Gravity Studies Of The Archean English River Subprovince, Western Superior Province, Manitoba And Ontario, Canada, Moira E. Campion Jan 1992

Metamorphic Petrology And Gravity Studies Of The Archean English River Subprovince, Western Superior Province, Manitoba And Ontario, Canada, Moira E. Campion

Theses and Dissertations

The tectonic development of the English River Subprovince (ERSP) of the Superior Province in Ontario and Manitoba, as with other Archean medium-high grade metasedimentary/gneiss terranes, is an area of active research. Geochemical and geophysical data were collected during this study to determine the metamorphic conditions of formation, and the relationship between surface and subsurface geology. The results of metamorphic studies by Henke (1984), Baumann (1985), Chipera (1985) and Reeb (1987) were also integrated with those of this study. The temperatures and pressures of formation, as well as detailed gravity characteristics, constrain the postulated tectonic model for the ERSP.

Chemical data …


Hydrogeologic Characterization Of A Discharge Wetland In Northeastern Grand Forks County, North Dakota, Dean R. Goebel Jan 1992

Hydrogeologic Characterization Of A Discharge Wetland In Northeastern Grand Forks County, North Dakota, Dean R. Goebel

Theses and Dissertations

Soil salinization associated with saline groundwater discharge results in decreased agricultural production in the central glacial Lake Agassiz plain of North Dakota. Saline discharge occurs in a belt of ephemeral wetlands in the lake plain. The physical and chemical hydrology of .the Lunby-stewart saline discharge wetland were investigated in order to provide information which could facilitate land management strategies applicable to this and other discharge wetlands.

Hydrologic data used to characterize the wetland were obtained from monitoring wells, staff gages, precipitation gages, borings, and earth electrical resistivity soundings. Temporal and spatial variations were observed in the water table, the vertical …


Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer Jan 1992

Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer

Theses and Dissertations

Biological denitrification controls nitrate distribution in the Elk Valley aquifer, which underlies approximately 725 square kilometres of northeastern North Dakota and provides drinking water for farms and rural communities in the area. Increased irrigation has raised concerns over potential contamination from agricultural practices. The purpose of this study was to establish the role of biological denitrification in minimizing concentration and distribution of nitrate and to determine the effect irrigation practices have on groundwater flow and nitrate distribution in the saturated zone.

The aquifer is unconfined and consists of up to 20 metres of glacial outwash and deltaic shale-rich sand deposits. …


The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck Jan 1992

The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck

Theses and Dissertations

Approximately 163 meters (535 feet) of the Paleocene Sentinel Butte Formation crop out in southcentral Williams county, North Dakota. To determine their mode of deposition and stratigraphic position within the formation, twelve stratigraphic sections were measured. These strata were deposited in alternating fluvial and lacustrine environments as determined by sedimentary structures, lithology, lithologic sequences, and fossil occurrences. A fining upward trend in grain size of the tabular sandstones, and the identification of epsilon cross-stratification in the tabular sandstones support a fluvial origin for some of the strata. The strongest evidence for the interpretation of lacustrine deposition is the presence of …


Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman Jan 1992

Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman

Theses and Dissertations

Subsidence at abandoned underground mines in south-central and southwest North Dakota has produced numerous sinkholes. Previous studies in the Northern Great Plains have suggested depression-focused recharge may be a significant ground water recharge mechanism in this region. Thus, sinkholes may increase soil moisture and ground water recharge. Current reclamation practices include filling sinkholes with non-topsoil fill material. However, the benefits of increases in soil moisture and ground water supplies may outweigh the benefits of expensive reclamation. The purpose of this study was to determine whether soil moisture and, hence, the potential for ground water recharge, was greater in sinkholes than …


Stratigraphic And Paleontologic Studies Of Paleocene And Oligocene Carbonate Facies Of The Eastern Gulf Coastal Plain, Jonathan Russel Bryan Dec 1991

Stratigraphic And Paleontologic Studies Of Paleocene And Oligocene Carbonate Facies Of The Eastern Gulf Coastal Plain, Jonathan Russel Bryan

Doctoral Dissertations

Shallow marine Paleogene carbonates of the Eastern Gulf Coastal Plain contain a variety of unique and largely undocumented facies. The Late Paleocene Salt Mountain Limestone of southwestern Alabama is a coral-algal-sponge buildup composed of large foram-algal packstone, algal bindstone, and sponge-coral bafflestone. Abundant coralline algae and a low diversity coral fauna are characteristic of Paleocene reefs, but sponges are rare in earliest Tertiary sediments. Their abundance in the Salt Mountain could indicate an opportunistic response of sponges as reef constructors after the extinction of rudist-coral communities in the Late Cretaceous.

The Bridgeboro Limestone, a rhodolith and coral-bearing limestone in southwestern …


Geology Newsletter- 1991, Department Of Geology Dec 1991

Geology Newsletter- 1991, Department Of Geology

Geological and Environmental Sciences News

Vol.1, No. 16

  • Core Research Lab
  • Faculty News
  • Service Staff News
  • Alumni/ Friends/ Former Faculty Notes
  • 1991 Speakers Program
  • New Alumni
  • Awards and Scholarships
  • Geology Club


Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman Dec 1991

Environmental Radiocesium In Subarctic And Arctic Alaska Following Chernobyl, M. Baskaran, J. J. Kelley, A. S. Naidu, D. F. Holleman

Environmental Science and Geology Faculty Research Publications

Radiocesium (¹³⁴ Cs and ¹³⁷ Cs) concentrations were measured in soil, plant and wildlife samples from subarctic to arctic Alaska. Concentrations of ¹³⁷ Cs ranged from below detectable or low levels in whale and fish samples to as high as 242 Bq/kg in lichen. For all potential human food items, the radiocesium concentrations measured in this study were below accepted permissible levels for human consumption. Chernobyl-derived radiocesium concentrations ranged from below detectable or low levels in all arctic samples (soil, sediment, lichen, whale, fish and caribou) to 32 Bq/kg in subarctic moss. Therefore the distribution and subsequent deposition of Chernobyl-derived …


Structural, Depositional, And Diagenetic Controls On Reservoir Development: St. Peter Sandstone, Newaygo County, Michigan, Mark S. Caldwell Dec 1991

Structural, Depositional, And Diagenetic Controls On Reservoir Development: St. Peter Sandstone, Newaygo County, Michigan, Mark S. Caldwell

Masters Theses

Enhanced reservoir quality in the Middle Ordovician St. Peter Sandstone is observed in gas bearing zones in wells located on domal structures. Geometry and degree of this enhanced porosity development is the result of the interplay of structural, depositional, and diagenetic controls. An integrated subsurface study of the Woodville/Goodwell field area was performed in order to document controls on hydrocarbon accumulation.

Recurrent structural growth of domal features throughout the Paleozoic is well documented by isopach mapping. Burial and thermal history studies indicate that hydrocarbons were generated in Ordovician aged source rocks during late Devonian to early Mississippian time, and accumulated …


Groundwater Levels In Nebraska, 1990, Gregory V. Steele, Perry B. Wigley Dec 1991

Groundwater Levels In Nebraska, 1990, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division

No abstract provided.


The Sloan Sag: A Mid-Miocene Volcanotectonic Depression, North-Central Mccullough Mountains, Southern Nevada, Hayden L. Bridwell Dec 1991

The Sloan Sag: A Mid-Miocene Volcanotectonic Depression, North-Central Mccullough Mountains, Southern Nevada, Hayden L. Bridwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the Hidden Valley area of the north-central McCullough Mountains, southern Nevada, mid-Miocene andesite and dacite domes, flows and pyroclastic units (the Sloan volcanics) partially fill a sag in the underlying Hidden Valley volcanics. The 13.5 km diameter sag formed during and/or after the eruption of the Sloan volcanics. Sagging was accommodated by a combination of movement on the McCullough Wash fault system, and subsidence into evacuated chambers.

Major, trace and rare-earth element geochemistry suggests that the rocks of the Sloan volcanics belong to four groups, each of which were produced by partial melting of chemically distinct sources. With the …


Metamorphic Evidence For Tilt Of The Spuzzum Pluton – Diminished Basis For The Baja British-Columbia Concept, E. H. Brown, Russ R. Burmester Oct 1991

Metamorphic Evidence For Tilt Of The Spuzzum Pluton – Diminished Basis For The Baja British-Columbia Concept, E. H. Brown, Russ R. Burmester

Geology Faculty Publications

To address the question of tilt versus translation as the mechanism responsible for discordance between paleomagnetic directions of Cretaceous plutons in the British Columbia Coast Plutonic Complex and the North American reference direction, metamorphic pressures around the margin of the Spuzzum pluton have been determined. Pressures are derived from microprobe analyses and evaluation of exchange equilibria in the assemblage garnet-biotite-plagioclase-aluminum silicate-quartz. Samples studied come from eight localities in the contact aureole around the pluton and encompass the area of a previous paleomagnetic study. The analyzed samples are coarse grained and exhibit textural features indicative of equilibrium crystallization following emplacement of …


Trace Fossils Of Shallow Subtidal To Dunal Ichnofacies In Bahamian Quaternary Carbonates, H. Allen Curran, Brian White Oct 1991

Trace Fossils Of Shallow Subtidal To Dunal Ichnofacies In Bahamian Quaternary Carbonates, H. Allen Curran, Brian White

Geosciences: Faculty Publications

Pleistocene and Holocene carbonate grainstones or calcarenites capping the islands of the Bahamas commonly contain distinctive animal and/or plant trace fossils. Three ichnocoenoses within the Skolithos and Psilonichnus ichnofacies are recognized in the transition from sediments deposited in the shallow shelf environment, commonly associated with coral reefs, to sediments of the coastal dune environment. Analog relationships between the trace fossils and modern tracemakers can be established in many cases, and this correspondence strengthens the interpretive model. Ophiomorpha

and Skolithos linearis characterize beds deposited in shallow shelf settings. Psilonich- nus upsilon, the fossil burrow of the ghost crab Ocypode quadrata …


Climate, Physiography, Geology, Hydrology And Land Use In The North Stirlings Area : A Precursory Report, R Lennard, R A. Nulsen, C E. Southwell Oct 1991

Climate, Physiography, Geology, Hydrology And Land Use In The North Stirlings Area : A Precursory Report, R Lennard, R A. Nulsen, C E. Southwell

Resource management technical reports

No abstract provided.


The Geomorphology Of Alluvial Fan Deposits On The West Flank Of The Blue Ridge, Augusta County, Virginia, Debra Lynn Duffy Oct 1991

The Geomorphology Of Alluvial Fan Deposits On The West Flank Of The Blue Ridge, Augusta County, Virginia, Debra Lynn Duffy

OES Theses and Dissertations

Large coalescing alluvial fans mantle the carbonate and shale formations west of the Blue Ridge mountains near Stuarts Draft, Virginia. Fan sediments are predominantly boulder and cobble gravels derived from the Antietam Quartzite, The fan complex consists of three alluvial units of significantly different ages. The surface of each fan unit was mapped using relative geomorphic position, soil color, clay content and thickness of Bt horizons, clast weathering, and degree of removal of depositional surfaces by stream incision. A five-category quartzite clast weathering scale developed for this study was very effective as a measure to distinguish map units. Stratigraphic data …


Fractures In The Jacobsville Sandstone And The Precambrian “W” Rocks In Eastern Marquette County, Michigan, Leonard Paul Belliveau Aug 1991

Fractures In The Jacobsville Sandstone And The Precambrian “W” Rocks In Eastern Marquette County, Michigan, Leonard Paul Belliveau

Masters Theses

The major fracture systems in the Jacobsville sandstone likely originated by reverse faulting on the Keweenaw fault and by glacially produced thrusting. Fracture orientations, apertures, and spacings are uniform in the Jacobsville sandstone and Lighthouse Point member of the Mona Schist, and are variable in the Lower member of the Mona schist and Compeau Creek gneiss. Fracture sets in the Compeau Creek gneiss exist in domains separated by metadiabase dikes. The metadiabase dikes relieved the strain produced by the Penokean orogeny by fracturing. Fractures present in inclusions, quartz veins, metadiabase and diabase dikes can be used to temporally evaluate the …


A Hydrogeochemical Characterization Of A Glacial-Drift Aquifer System In Southwest Michigan, Patrick G. Barrese Aug 1991

A Hydrogeochemical Characterization Of A Glacial-Drift Aquifer System In Southwest Michigan, Patrick G. Barrese

Masters Theses

A hydrogeochemical investigation of the Schoolcraft Aquifer, an unconfined, glacial-drift aquifer located in southwest Michigan, was undertaken to focus on three topics: (1) the geochemical definition of recharge and discharge zones both vertically and laterally along projected flow paths, (2) the description of the carbonate and redox chemical systems, and (3) groundwater degradation associated with excessive nitrate, ammonium, and chloride concentrations.

The results of the study were inconclusive in defining recharge and discharge zones; however, iron and alkalinity concentrations were identified as possible indices for recharge and discharge conditions. The carbonate analysis indicated that the aquifer is saturated with respect …


An Analysis Of Hydrogeologic Factors Affecting Aquifer Vulnerability In Southwestern Michigan, Steven E. Benton Aug 1991

An Analysis Of Hydrogeologic Factors Affecting Aquifer Vulnerability In Southwestern Michigan, Steven E. Benton

Masters Theses

In southwestern Michigan aquifers are threatened by human activities. Parameter/factor weighting systems are used to rate aquifer vulnerability. Hydrogeologic factors affecting aquifer vulnerability were investigated in this study.

Well records, soil surveys, hydrogeologic reports, and partial chemical analyses were used to obtain data on the aquifers, soil types, glacial sediments, and types of contaminants. Data analysis included comparisons of means and medians, factor analysis, and Pearson and Spearman Correlation analysis.

The results indicate that the aquifers in Kalamazoo County are not protected. Depending on the type of glacial sediment, hydrogeologic factors that protect aquifers are clay thickness and the depth …