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Articles 1441 - 1470 of 1545

Full-Text Articles in Earth Sciences

Trace Metals And Pyrite In Sediments Of Chesapeake Bay, Robert S. Kluckhohn Oct 1990

Trace Metals And Pyrite In Sediments Of Chesapeake Bay, Robert S. Kluckhohn

OES Theses and Dissertations

The formation and cycling of iron sulfides within anoxic sediments can affect the cycling of trace metals. The sediments at station CB-27 (near Annapolis, Maryland) in Chesapeake Bay were rich in FeS (39% of TS), low in greigite (3.6% of TS), and has a relatively constant pyrite concentration (50 - 60% of TS) with depth. The percent composition of total metals in pyrite were 25.7% cu, 11.8% Zn, 15.8% Fe, and non-detectable to 2.1% Cd. At Station CB- 28 (near the Choptank River), the sediments were low in FeS (1.7% of TS), richer in greigite (up to 14% of TS), …


Hydrogeology And Hydrogeochemistry Of The Tekonsha Moraine And Adjacent Interlobate Deposits In Charleston Township, Kalamazoo County, Michigan, Victor V. Melbardis Aug 1990

Hydrogeology And Hydrogeochemistry Of The Tekonsha Moraine And Adjacent Interlobate Deposits In Charleston Township, Kalamazoo County, Michigan, Victor V. Melbardis

Masters Theses

Hydrogeochemical analyses and hydrogeologic interpretations provide the basis for an understanding of local ground-water flow, in a 12 square mile study area, transected by the Tekonsha Moraine and bound by glaciofluvial deposits. Glacial tills separate an upper and lower aquifer system throughout most of the area.

Degraded and tritiated ground water is present in the lower aquifer system. A negative correlation (-0.62) between tritium concentrations and depth is statistically significant (.04). In this local system, hydrochemical trends are characterized by decreases in sulfate percentages and increases in bicarbonate in the direction of ground-water flow. Statistical evaluation of the hydrochemical data …


Metal Mobilization From A Near-Shore Lake Sediment Under Simulated Acidic Groundwater Inputs, Raveendra V. Ika Jul 1990

Metal Mobilization From A Near-Shore Lake Sediment Under Simulated Acidic Groundwater Inputs, Raveendra V. Ika

OES Theses and Dissertations

Simulation of acidic groundwater passing through lake sediments was conducted under controlled conditions in a laboratory. Three sediment cores collected intact from the near-shore region of an acidic lake were subjected to simulated groundwater inputs of initially identical chemistry for a seven day period. Following this period water being used in the simulation for two of the sediment cores was acidified by hydrochloric acid (HC1) addition to examine the ability of these sediments to neutralize acidic groundwater with varying H+ concentration.

Simulated acidic water passing through the sediment cores mobilized significant amounts of metals. The sediment acted as a …


Geochemical Evolution Of Ferruginous Bauxite Deposits In Northwestern Oregon And Southwestern Washington, Joseph Michael Fassio Jun 1990

Geochemical Evolution Of Ferruginous Bauxite Deposits In Northwestern Oregon And Southwestern Washington, Joseph Michael Fassio

Dissertations and Theses

Ferruginous bauxite deposits developed from flows of the Columbia River Basalt Group in northwestern Oregon and southwestern Washington. Samples of the iron pisolite and the gibbsite nodular zones from the upper portion of the weathering profile of drill core from Columbia County, Oregon and Cowlitz County, Washington, were analyzed by instrumental neutron activation. The mineralogy was determined using Xray diffraction and Mossbauer spectroscopy.

The gibbsite nodular zone is above the clay-rich saprolite or relic basalt zone. The nodules contain relic vesicles and well preserved relic plagioclase microlites. Gibbsite occurs with poorly crystalline goethite and hematite in the gibbsite nodular zone. …


A Comparison Of Metals In Several Ahermatypic Corals And Surficial Sediments: Mobile Pinnacles And Hoffa Reef, Northcentral Gulf Of Mexico, Kathryn M. Conko Apr 1990

A Comparison Of Metals In Several Ahermatypic Corals And Surficial Sediments: Mobile Pinnacles And Hoffa Reef, Northcentral Gulf Of Mexico, Kathryn M. Conko

OES Theses and Dissertations

Metal concentrations in marine sediment and carbonate secreting invertebrates are representative of surrounding environmental chemistry. Aluminum, Ba Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, and Zn were measured in carbonate and terrigenous phases of the $<$63 um fraction of sediment samples from two locations in the northcentral Gulf of Mexico. Enrichment factors indicate that Al, Ba, Cu, Cr, Mg, Mn, and Ni are all slightly depleted in these sediments relative to crustal abundances. Discriminant function analyses shows that the concentrations of five elements differ between locations.

Ahermatypic coral (106 specimens) from five genera collected from the study sites were analyzed for Cd, Cu, Cr, Pb, Zn, Mn, Sr, Ba, Fe, Ca and Mg. Eight elements vary between some genera, Al and Ba also vary in concentration in corals between either location. All elements except Sr are significantly depleted in the coral with respect to Ca in the …


Geochemistry Of Selected Maine Peat Deposits, Stephen A. Norton Jan 1990

Geochemistry Of Selected Maine Peat Deposits, Stephen A. Norton

Maine Collection

Geochemistry of Selected Maine Peat Deposits

by Steven Allen Norton

Maine Geological Survey, Department of Conservation, Augusta, Maine, 1990.

Contents: Introduction / Purpose of Study / Location of Study Sites / Methods / Acknowledgements / Results / Water Chemistry / Dating of Short Cores / Chemistry of Short Cores / Core Interpretations / Summary / References Cited


Biological Markers In Lower Jurassic Synrift Lacustrine Black Shales, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, Jay F. Akes, Paul E. Meriney Jan 1990

Biological Markers In Lower Jurassic Synrift Lacustrine Black Shales, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, Jay F. Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The East Berlin Formation (Lower Jurassic, Hartford basin, Connecticut, U.S.A.) is distinctive for its six cyclic units of lacustrine black shale and gray mudstone. separated by playa and fluvial redbeds. The black shales arc each about a meter thick and were deposited in subtropical, thermally stratified, oligomictic lakes, the youngest of which (lakes 3 through 6) were large enough to flood most of the basin and attained depths of several tens of meters.

The saturate fractions of solvent extracts of organic-rich black shales from each of the six lakes, collected at fresh roadcuts near East Berlin, arc dominated by extended …


Characterization Of Organic Sulfur Compounds In Coals And Coal Macerals, Stephen R. Palmer, Edwin J. Hippo, Michael A. Kruge, John C. Crelling Jan 1990

Characterization Of Organic Sulfur Compounds In Coals And Coal Macerals, Stephen R. Palmer, Edwin J. Hippo, Michael A. Kruge, John C. Crelling

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Peroxyacetic acid oxidation has been used to investigate the type and distribution of organic sulfur species in samples of vitrinite, sporinite and inertinite, separated from the Herrin No.6 and an Indiana No.5 coal seam. It was established that organic sulfur species were selectively preserved during oxidation and their analysis led to some of the first sulfur-33 NMR spectra obtained for coal. The effects of maceral separation processes on model compounds were also studied. Results from our studies support the following conclusions: 1). Different macerals have different distributions and types of organic sulfur species. 2). Organic sulfur compounds in coal occur …


Organic Geochemistry Of A Lower Jurassic Synrift Lacustrine Sequence, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, David F. Bensley, John C. Crelling, R Jay Akes, Paul E. Meriney Jan 1990

Organic Geochemistry Of A Lower Jurassic Synrift Lacustrine Sequence, Hartford Basin, Connecticut, U.S.A., Michael A. Kruge, John F. Hubert, David F. Bensley, John C. Crelling, R Jay Akes, Paul E. Meriney

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Synrift terrestrial strata of the Lower Jurassic East Berlin Formation (Hartford basin, Connecticut, U.S.A.) record cyclical expansion and contraction of major lakes, six of which were deep enough to develop anoxic bottom waters. We have studied one representative lacustrine sequence in detail, sampling a new roadcut near the village of East Berlin. The section examined is 4 m thick, with a gray siltstone at the base, deposited in shallow water, overlain by an organic-rich black shale (deep water), succeeded in turn by another gray siltstone, deposited as the lake waters gradually receded. The upper gray siltstone is chemically distinct from …


Mining In Maine : Past, Present, And Future, Carolyn A. Lepage Jan 1990

Mining In Maine : Past, Present, And Future, Carolyn A. Lepage

Maine Collection

Mining in Maine : Past, Present, and Future

by Carolyn A. Lepage, Michael E. Foley, and Woodrow B. Thompson

Maine Geological Survey, Department of Conservation, Augusta, Me., 1990.

Contents: Introduction / The Early Years: Pre-Civil War / The Civil War to World War II / The War Years of the 1940's / The Postwar Years: 1940's to 1960 / The 1960's / The 1970's / Maine Mineral Resources Association / The 1980's / Current Mining and Exploration / Future Potential / Acknowledgments / References


Origin, Sedimentary Geochemistry, And Correlation Of Middle And Late Ordovician K-Bentonites: Constraints From Melt Inclusions And Zircon Morphology, Carsten Schirnick Jan 1990

Origin, Sedimentary Geochemistry, And Correlation Of Middle And Late Ordovician K-Bentonites: Constraints From Melt Inclusions And Zircon Morphology, Carsten Schirnick

Geology Theses and Dissertations

The present study of Paleozoic K-bentonites demonstrates that the geochemistry of melt inclusions and the morphology of zircons can be studied by inexpensive and simple-to-use methods, which rely on phenocrysts. Constraints are obtained that lead to (a) the origin of these altered volcanic ashes, (b) the geochemistry of ash-to-K-bentonite-alteration, and (c) the reliable correlation of extensively altered volcanic ashes (i.e. K-bentonites).
Silicic melt inclusions (i.e. non-devitrified) have been found in quartz and zircon phenocrysts contained within Ordovician and Devonian K-bentonites from New York State, the Upper Mississippi Valley, and Pennsylvania. Origin, source, and tectonic setting of the volcanism that produced …


Application Of A Trace Element Fractionation Model To Cumulate Gabbroic Xenoliths Of Mauna Kea, Hawaii, Ulrike Eberle Jan 1990

Application Of A Trace Element Fractionation Model To Cumulate Gabbroic Xenoliths Of Mauna Kea, Hawaii, Ulrike Eberle

Geology Theses and Dissertations

A trace element fractionation model originally designed to relate plutonic rocks containing a trapped glass component to a complementary volcanic rock suite was applied to olivine and opaque-oxide gabbroic xenoliths from the summit cone of Mauna Kea, Hawaii.
The mathematical model which is based on the Rayleigh Fractionation Law was extended to include the various phases present in these two groups of gabbros and was generalized to treat multiple trace elements, in this case four. These results were incorporated in a new FORTRAN program using the interval-bisection method to greatly improve the convergence time in the numerical solutions.
Calculated results …


Petrology And Major Element Geochemistry Of Basaltic Glasses From The Blanco Trough, Northeast Pacific, Glenn A. Gaetani Jan 1990

Petrology And Major Element Geochemistry Of Basaltic Glasses From The Blanco Trough, Northeast Pacific, Glenn A. Gaetani

Geology Theses and Dissertations

The original electron microprobe analyses of suite of basaltic glasses recovered in 1968 by W.G. Melson and co-workers from the Blanco Trough have extremely unusual characteristics. Their compositions plot in a region of the normative Ol-Di-Pl-SiO2 tetrahedron which suggests that they represent liquids in equilibrium with an upper mantle assemblage of olivine + orthopyroxene at 10-15 kb. Given the present state of controversy surrounding the composition and depth of origin of primary MORB, natural examples of such liquids would be very important. The major element variations observed in the suite imply that the dominant phases are olivine and an iron-aluminum …


Geochemistry Of Garnet Xenocrysts And Garnet-Bearing Xenoliths In Ordovician Bentonites, Barbara Bock Jan 1990

Geochemistry Of Garnet Xenocrysts And Garnet-Bearing Xenoliths In Ordovician Bentonites, Barbara Bock

Geology Theses and Dissertations

Within outcrops of the black Utica shales south of the Mohawk Valley narrow re-entrants parallel with stratification are visible, often accompanied -by a marked orange-staining of the underlying strata. These rentrant features indicate the presence of bentonites weathered back faster then the enclosing shales. These bentonites are presumably magmatic ashes related to extensive volcanism when an island arc collided with the North American continent in the late Ordovician about 450 million years ago (Taconic orogeny).
Bentonites are good stratigraphic markers because of the short time-interval they represent and the large area they cover. Therefore they are commonly used as correlation …


Identification And Quantitation Of Volatile Amines In Marine Sediments, Chuen Mei Huang Oct 1989

Identification And Quantitation Of Volatile Amines In Marine Sediments, Chuen Mei Huang

Chemistry & Biochemistry Theses & Dissertations

Pore waters which were taken from sediments of the Chesapeake Bay were analyzed to determine the presence of volatile amines. A purge-and-trap technique was used to concentrate the amines. Then, following derivatization with heptaflourobutyric anhydride, the HFBA-amines were analyzed by gas chromatography with electron capture detection and with mass spectrometric detection. One secondary amine, diethylamine with a concentration of 0.3-0.6 uM, was found in a total of three pore water samples from cores collected on two different dates. A primary amine, sec-butylamine with a concentration of O. 05 AIM, was also found in one of these same samples. Another primary …


A Geochemical Study Of The Eagle Creek Formation In The Columbia River Gorge, Oregon, Rachel Ann Carlin Jun 1988

A Geochemical Study Of The Eagle Creek Formation In The Columbia River Gorge, Oregon, Rachel Ann Carlin

Dissertations and Theses

The Early Miocene Eagle Creek Formation, a series of volcanic mudflows and debris flows, is exposed in the Columbia River Gorge about 64 kilometers east of Portland, Oregon. Eighty-seven samples were analyzed using instrumental neutron activation analysis for trace element concentrations. Eleven samples were analyzed by Dr. Peter Hooper at Washington State University using X-ray Fluorescence for major element chemistry. These data were used to determine that the Eagle Creek Formation compositionally ranges from andesite to dacite.


Geochemical Stratigraphy Of The Dooley Rhyolite Breccia And Tertiary Basalts In The Dooley Mountain Quadrangle, Oregon, David Neale Whitson May 1988

Geochemical Stratigraphy Of The Dooley Rhyolite Breccia And Tertiary Basalts In The Dooley Mountain Quadrangle, Oregon, David Neale Whitson

Dissertations and Theses

The Dooley Rhyolite Breccia in northeast Oregon was erupted between 12 and 16 million years ago, from central vents and linear feeder dikes within the Dooley Mountain quadrangle. The peraluminous, high-silica rhyolites of the formation were erupted over an irregular highland of eroded pre-Tertiary metamorphic rocks locally overlain by intracanyon, Eocene Clarno-type basalt flow(s). The Dooley Rhyolite Braccia is exposed in a tectonically disrupted, north-south trending graben across the Elkhorn Range. The formation is variable in thickness with maximum thickness exceeding 660 meters in the south and 600 meters in the north half of the quadrangle. Volumetrically the formation is …


Sedimentology, Structure, And Geochemistry Of The Galice Formation: Sediment Fill Of A Back-Arc Basin And Island Arc In The Western Klamath Mountains, Rosann Park-Jones Jan 1988

Sedimentology, Structure, And Geochemistry Of The Galice Formation: Sediment Fill Of A Back-Arc Basin And Island Arc In The Western Klamath Mountains, Rosann Park-Jones

Geology Theses and Dissertations

The western Jurassic belt of the Klamath Mountains is an ideal locale for the study of ophiolite genesis, island arc development, and study of flysch deposition from a nearby eroding island arc and continental margin. Closure and imbrication of an inferred back-arc basin coincided with the Late Jurassic Nevadan orogeny (ca 150 Ma). The Galice Formation is the youngest formation involved in the Nevadan orogeny (Lanphere et al., 1968). In the type section in southwestern Oregon, the Galice structurally overlies the Rogue Formation volcaniclastics. The Rogue Formation has been previously interpreted as an island arc assemblage (Garcia, 1979). The type …


Discrimination Of Subparallel Beach Ridges Using Detrital Ilmenite Composition And Fourier Shape Analysis, Allen E. Evans Jr. Oct 1987

Discrimination Of Subparallel Beach Ridges Using Detrital Ilmenite Composition And Fourier Shape Analysis, Allen E. Evans Jr.

OES Theses and Dissertations

Elemental composition (Fe, Ti, Mn, Mg, V, Cu, Ni, Zn, and Cr) and Fourier shape analysis of magnetically separated detrital ilmenite from seven Pleistocene and modern beach sand deposits of the Southeastern Virginia Coastal Plain were used to distinguish each deposit. Geomorphic expression, crosscutting relationships and proximity to the present shoreline differentiates the relative age of the seven sampled beach deposits. Analysis of ilmenite elemental composition, independent of geomorphic expression, distinguished beach sands of

different age and was successful in determining that each beach contained ilmenite similar in composition. Of the seven beach ridges tested, subtle yet significant differences in …


Sulfide In Shelf/Slope Waters Of The Western Atlantic, Christian F. Krahforst Oct 1987

Sulfide In Shelf/Slope Waters Of The Western Atlantic, Christian F. Krahforst

OES Theses and Dissertations

Sulfide in the surface ocean has been recently considered as a source of hydrogen sulfide gas in the marine boundary layer. This "oxic" sulfide may also be important as a ligand in trace metal complexation. In the absence of actual data, the existence of sulfide in the ocean mixed layer remains speculative. The purpose of this study was to develop a sensitive technique (having picomolar detection limits) for the determination of sulfide in seawater, and to investigate the distribution of sulfide in the surface ocean.

In order to assess the abundance and distribution of sulfide in surface waters, samples were …


Isotope Content And Temperature Of Precipitation In Southern Nevada, August 1983-August 1986, W. K. Milne, Larry Benson, P. W. Mckinley Jan 1987

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 …


Identification Of Endmembers For Magma Mixing In Little Sitkin Volcano, Alaska, Douglas A. Wolf Jan 1987

Identification Of Endmembers For Magma Mixing In Little Sitkin Volcano, Alaska, Douglas A. Wolf

Geology Theses and Dissertations

Little Sitkin island is an Aleutian calc-alkalic volcanic center that has erupted a suite of lavas ranging from andesite through rhyodacite. Whole-rock chemistry of these lavas indicates contrasting evolutionary processes; major-oxide silica variation diagrams exhibit linear trends that are suggestive of magma-mixing while trace-element trends are largely controlled by accessory-phase fractionation.
Plagioclase, the dominant phenocryst phase in all lavas, commonly occurs in two distinct populations with markedly different compositions and textures. Both normal and reverse zonation is noted in the plagioclase and clinopyroxene of several samples. In addition, clinopyroxene is found as rims on orthopyroxene grains and as cores with …


Granitic Pegmatites In The Southeastern Adirondacks: Their Use As Indicators Of Temperature, Pressure, And Fluid Conditions During A Late Stage Of The Grenville Orogeny, John P. Mihalich Jan 1987

Granitic Pegmatites In The Southeastern Adirondacks: Their Use As Indicators Of Temperature, Pressure, And Fluid Conditions During A Late Stage Of The Grenville Orogeny, John P. Mihalich

Geology Theses and Dissertations

Granitic pegmatites associated with the Grenville orogeny intrude a mid-Proterozoic, upper amphibolite to near granulite facies terrane in the southeastern Adirondack Mountains of New York State. The inferred anatectic, fluid-saturated, and minimum melt characteristics of the pegmatites suggest that they can be used as analogs of the "granite" or "haplogranite" system, and as indicators of crustal temperature, pressure, and fluid conditions during a late stage of the Grenville orogeny. Bulk chemical compositions of seven simple, undeformed pegmatites in the southeastern Adirondacks indicate that they are generally depleted in silica and sodium, and enriched in potassium, relative to experimental data on …


Geology, Geochemistry, And Geochronology Of The Lems Ridge Olistostrome, Klamath Mountains, California, Matthias Ohr Jan 1987

Geology, Geochemistry, And Geochronology Of The Lems Ridge Olistostrome, Klamath Mountains, California, Matthias Ohr

Geology Theses and Dissertations

The Lems Ridge olistostrome (LRO), located within the western Jurassic belt of the Klamath Mountains geologic province, is a melange unit showing a distinct block-in-matrix fabric. The conformable relationship to both an igneous basement and the overlying flysch of the Late Jurassic Galice Formation points to a sedimentary origin. The lack of pervasive deformation and the internal stratification also support a predominantly olistostromal origin of the LRO. The matrix of the LRO consists of pebbly mudstone which interfingers with tuffaceous greenstone and tuff-breccias. Subordinate beds of chert, argillite, and sandstone are also present. The matrix contains abundant ophiolitic clasts, fragments …


Structural, Remote Sensing And Multivariate Correlation Methods As Aids To Mineral Exploration, Central Ireland, D.W. Coller, M.F. Critchley, J.M. Dolan, Ciaran Mcdonnell, C.J. Murphy, W.E.A. Phillips, D.J. Sanderson Dec 1986

Structural, Remote Sensing And Multivariate Correlation Methods As Aids To Mineral Exploration, Central Ireland, D.W. Coller, M.F. Critchley, J.M. Dolan, Ciaran Mcdonnell, C.J. Murphy, W.E.A. Phillips, D.J. Sanderson

Books/Book chapters

This work discusses structural, remote sensing and multivariate correlation methods as aids to mineral exploration in West Central Ireland. The work was performed as part of the EU-funded CREST project.


Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart Apr 1986

Transient Electromagnetic Sounding For Groundwater, David V. Fitterman, Mark T. Stewart

Geology Faculty Publications

The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high-porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and …


Biomarker Geochemistry Of The Miocene Monterey Formation, West San Joaquin Basin, California: Implications For Petroleum Generation, Michael A. Kruge Jan 1986

Biomarker Geochemistry Of The Miocene Monterey Formation, West San Joaquin Basin, California: Implications For Petroleum Generation, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Much of the Miocene Monterey Formation of California is rich in biogenic sediment, especially organic matter and silica. Because of the geologic structure, the Monterey in the subsurface near Lost Hills in the San Joaquin Basin forms a natural laboratory for the study of the diagenetic responses of these materials. Rocks of similar age and lithology are buried to depths ranging between 500 and 3500 m, and are thus exposed to a temperature range of 45–130°C. The diagenetic progression of silica from opal-A to opal-CT to microquartz is well-documented in Monterey burial history studies. However, diagenetic indicators need to be …


A Stratigraphic-Geochemical Study Of The Troutdale Formation And Sandy River Mudstone In The Portland Basin And Lower Columbia River Gorge, Rodney Duane Swanson Jan 1986

A Stratigraphic-Geochemical Study Of The Troutdale Formation And Sandy River Mudstone In The Portland Basin And Lower Columbia River Gorge, Rodney Duane Swanson

Dissertations and Theses

Hyaloclastic sediment forms an identifiable stratigraphic interval within the Troutdale Formation that can be traced from the Bridal Veil channel to the Portland basin. Hyaloclastic sediment composed chiefly vitric sands is found interbedded with muds, sandy muds and gravels penetrated by wells in northeast Portland are correlated with the upper member of the Troutdale Formation. These beds are characteristic of the informal upper member of the Troutdale Formation in the Bridal Veil channel of the ancestral Columbia River (Tolan and Beeson, 1984) and the type area of the Troutdale Formation exposed along the Sandy River (Trimble, 1963). Fluvially deposited hyaloclastic …


On The Linear Relation Between Mb And Ms For Discrimination Between Explosions And Earthquakes, Ali A. Nowroozi Jan 1986

On The Linear Relation Between Mb And Ms For Discrimination Between Explosions And Earthquakes, Ali A. Nowroozi

OES Faculty Publications

Summary. The statistical capability of the mb :Ms, discriminant for the discrimination of earthquake and explosion populations is examined by application of discriminant functions to a group of 83 explosions and 72 earthquakes in Eurasia. Equations are derived for the probability that an event is an earthquake or an explosion. The positive sign of DIS in the decision index equation,

DIS, = 34.3383 - 11.9569 mbi, + 7.1 161 Msi,

indicates that the event i is an earthquake. Its negative sign indicates that event i is an explosion. The probability of …


The Geology, Geochemistry, And Alteration Of Red Butte, Oregon: A Precious Metal-Bearing Paleo Hot Spring System, Carol Susan Evans Nov 1985

The Geology, Geochemistry, And Alteration Of Red Butte, Oregon: A Precious Metal-Bearing Paleo Hot Spring System, Carol Susan Evans

Dissertations and Theses

Red Butte is located 60 km south of Vale, Oregon, about 20 km west of the Oregon/Idaho border. The butte is within the Owyhee Upland physiographic province of eastern Oregon which lies at the intersection of the Western Snake River Plain, the High Lava Plains, and the Northern Basin and Range provinces.

The butte is composed of Miocene to Pliocene lacustrine and fluvial volcaniclastic sediments. The topography of the butte is controlled by silicification of the sandstones and mudstones which cap it. Silicification and hydrothermal alteration are both structurally and stratigraphically controlled. North-trending normal faults dominate the area, and show …