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Geology

1990

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Articles 31 - 60 of 112

Full-Text Articles in Physical Sciences and Mathematics

Laramide Deformation In Precambrian Granitic Rocks, Northeastern Wind River Range, Wyoming, Mark A. Dubois May 1990

Laramide Deformation In Precambrian Granitic Rocks, Northeastern Wind River Range, Wyoming, Mark A. Dubois

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fractures and faults in the Jakey's Fork area, northeastern Wind River Range, Wyoming, caused by brittle Laramide deformation in the Precambrian granitic basement have been studied in detail at airphoto, outcrop, and thin-section scales. The study area is bounded on the south by the approximately east-west and vertical Jakey's Fork Fault and on the east by the approximately northwest-southeast and vertical Ross Lakes Fault. Both were active during Laramide deformation. Four distinct structural domains, defined by fracture pat terns and proximity to the two major faults nave emerged in this study. The areas are: 1) Along Ross Lakes Fault granite …


Geology, Volcanology, And Petrology Of Cerro Bravo, A Young, Dactic, Stratovolcano In West-Central Colombia, David Tondl Lescinsky Apr 1990

Geology, Volcanology, And Petrology Of Cerro Bravo, A Young, Dactic, Stratovolcano In West-Central Colombia, David Tondl Lescinsky

LSU Historical Dissertations and Theses

The northernmost active Andean volcano, Cerro Bravo is a small, young, and very explosive stratovolcano. Cerro Bravo has produced voluminous tephra deposits, that are found> 30 km away, as well as, pumice flow deposits, block and ash flow deposits, and high-aspect lava flows, which are found proximally to the volcano. There have been eight episodes of activity during the past 6250±110 years (Herd, 1982), with the most recent <200 years ago and the present being a period of quiescence with no visible activity or thermal manifestations. Stratigraphic relationships suggest the occurrence of an initial explosive phase and a concluding effusive phase of activity during individual episodes. The products of volcanic activity at Cerro Bravo are a chemically and mineralogically monotonous suite of medium-K dacite and high-silica andesite (59.2- 67.5% SiO2 pumices and lavas. The dominant phenocrysts present are plagioclase and hornblende (oxyhomblende in lavas) with lesser quantities of orthopyroxene, titanomagnetite, and rare augite and biotite also present. Petrology and eruption dynamics …


Geology Of The Si̇vas-Erzi̇ncan Tertiary Basin, H.Tahsin Akti̇mur, M.Ender Teki̇rli̇, M.Emin Yurdakul Apr 1990

Geology Of The Si̇vas-Erzi̇ncan Tertiary Basin, H.Tahsin Akti̇mur, M.Ender Teki̇rli̇, M.Emin Yurdakul

Bulletin of the Mineral Research and Exploration

No abstract provided.


The Fault Trace Of 1953 Yeni̇ce-Gönen Earthquake And The Westernmost Known Extension Of The Naf System In The Bi̇ga Peninsula, Erdal Herece Apr 1990

The Fault Trace Of 1953 Yeni̇ce-Gönen Earthquake And The Westernmost Known Extension Of The Naf System In The Bi̇ga Peninsula, Erdal Herece

Bulletin of the Mineral Research and Exploration

No abstract provided.


Metamorphism And Fission-Track Age Determination Of Apatite Crystals From Demi̇rci̇-Borlu Region, Gördes Submassif Of The Menderes Massifwestern Turkey, Osman Candan, Cahit Helvaci, G. Böhler, G. Walder, T.D. Mark Apr 1990

Metamorphism And Fission-Track Age Determination Of Apatite Crystals From Demi̇rci̇-Borlu Region, Gördes Submassif Of The Menderes Massifwestern Turkey, Osman Candan, Cahit Helvaci, G. Böhler, G. Walder, T.D. Mark

Bulletin of the Mineral Research and Exploration

No abstract provided.


A “Drastic” Evaluation Of The Ground-Water Pollution Potential Of Karst Terrain: Lost River Ground-Water Basin, Warren County, Kentucky, David Baize Apr 1990

A “Drastic” Evaluation Of The Ground-Water Pollution Potential Of Karst Terrain: Lost River Ground-Water Basin, Warren County, Kentucky, David Baize

Masters Theses & Specialist Projects

Karst terrains, such as the Lost River Karst Ground-Water Basin, are extremely vulnerable to ground-water contamination. Seven physical factors: depth to water, recharge, aquifer media, soil media, topography, impact of the vadose zone, and hydraulic conductivity, are evaluated using the DRASTIC system to determine the ground-water pollution potential of the study area. A numerical value is calculated for each of the seven factors, and a map layer for each factor is produced. These layers are then “added” together to produce a DRASTIC ground-water pollution potential map. The effectiveness of each factor in evaluating the pollution potential of karst terrain is …


Stromatolites Of The Lower Cambrian Deep Spring Formation; Mount Dunfee, Esmeralda County, Nevada, Lynn Oliver Apr 1990

Stromatolites Of The Lower Cambrian Deep Spring Formation; Mount Dunfee, Esmeralda County, Nevada, Lynn Oliver

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Middle Member of the Lower Cambrian Deep Spring Formation at Mount Dunfee, Nevada contains a diverse assemblage of stromatolites that formed on a tide- and storm-dominated, siliciclastic-influenced, carbonate shelf. The stromatolites formed in a shallow subtidal environment within and near active oolite shoals under strongly focused currents. The stromatolites occur in four different lithofacies: (1) bioherms of digitate stromatolites, (2) bioherms and biostromes of inclined stromatolites, (3) isolated forms of massive and hemispheroidal stromatolites, and (4) a biostrome of cryptomicrobial boundstones. The first three lithofacies are interpreted as microbial reefs. They had topographic relief, formed in active agitated waters, …


A New Carbonifereous And Permian Finding In The Karakaya Nappe, Erdin Bozkurt Mar 1990

A New Carbonifereous And Permian Finding In The Karakaya Nappe, Erdin Bozkurt

Bulletin of the Mineral Research and Exploration

No abstract provided.


Geology Of The Balikesi̇r-Bandirma Region (Northwest Anatolia), Petrology Of The Tertiary Volcanism And Its Regional Distribution, Tuncay Ercan, Erdem Ergül, Ferit Akçören, Ahmet Çeti̇n, Salâhi Grani̇t, Jerf Asutay Mar 1990

Geology Of The Balikesi̇r-Bandirma Region (Northwest Anatolia), Petrology Of The Tertiary Volcanism And Its Regional Distribution, Tuncay Ercan, Erdem Ergül, Ferit Akçören, Ahmet Çeti̇n, Salâhi Grani̇t, Jerf Asutay

Bulletin of the Mineral Research and Exploration

No abstract provided.


Progressive Brütle-Ductile Deformati̇on Dm The Demi̇rköy Plüton Of The Strandjha Massive Of Thrace – Turkey, M-Atilla Çağlayan, Metin Şengün, Ayhan Yurtsever Mar 1990

Progressive Brütle-Ductile Deformati̇on Dm The Demi̇rköy Plüton Of The Strandjha Massive Of Thrace – Turkey, M-Atilla Çağlayan, Metin Şengün, Ayhan Yurtsever

Bulletin of the Mineral Research and Exploration

No abstract provided.


Impli̇cati̇ons On Geology, Genesis And Ori̇gi̇n Of Çayirli Manganese Deposit, Ankara, Central Anatolia, Vedat Oygür Mar 1990

Impli̇cati̇ons On Geology, Genesis And Ori̇gi̇n Of Çayirli Manganese Deposit, Ankara, Central Anatolia, Vedat Oygür

Bulletin of the Mineral Research and Exploration

No abstract provided.


Features And Origin Of Bi̇lluri̇k Dere (Elaziğ) Mineralizations, Ahmet Şaşmaz, Ahmet Sağiroğlu Mar 1990

Features And Origin Of Bi̇lluri̇k Dere (Elaziğ) Mineralizations, Ahmet Şaşmaz, Ahmet Sağiroğlu

Bulletin of the Mineral Research and Exploration

No abstract provided.


Bazile Triangle Groundwater Quality Study, David C. Gosselin Feb 1990

Bazile Triangle Groundwater Quality Study, David C. Gosselin

Conservation and Survey Division

No abstract provided.


Strain And Volume Loss In A Second Order Buckle Fold, Central Appalachian Valley And Ridge, U.S.A., Michelle J. Markley Jan 1990

Strain And Volume Loss In A Second Order Buckle Fold, Central Appalachian Valley And Ridge, U.S.A., Michelle J. Markley

Honors Papers

Large scale thrusts and imbricates overlain by folded sedimentary strata characterize structure in the Valley and Ridge Province of the Central Appalachians. The Cambrian Waynesboro Formation is a decollement zone that detached an imbricated Cambro-Ordovician sequence from an unfaulted Pre-Cambrian basement. The Ordovician Martinsburg Shale is a second zone of major detachment that de-coupled the blind thrust system in the Cambro-Ordovician carbonates from the overlying orogenic wedge. Thus, the Central Valley and Ridge deformed during the late Paleozoic Alleghenian orogeny as a three tiered system consisting of the undeformed basement, the imbricated stiff layer, and the primarily folded cover layer. …


Use Of Limestone, Lime, And Dolomite For So2 Emission Control In Kentucky, Garland R. Dever Jr. Jan 1990

Use Of Limestone, Lime, And Dolomite For So2 Emission Control In Kentucky, Garland R. Dever Jr.

Information Circular--KGS

Flue-gas desulfurization and atmospheric fluidized-bed combustion systems for sulfur dioxide (SO2) emission control have been installed at 13 coal- and gas-fired plants and one research laboratory in Kentucky. Limestone, lime, and dolomite are the principal SO2 sorbents used in these systems.

Nine coal-fired, electricity-generating plants in the State have installed wet-scrubbing systems for flue-gas desulfurization. Lime-based scrubbers are using Thiosorbic® lime, produced from the Camp Nelson Limestone (Ordovician) of north-central Kentucky, and carbide lime, a byproduct from the manufacture of acetylene in Louisville. Limestone-based scrubbing systems at three of the plants have used stone from the Warsaw, …


High-Volume Oil Discovery In Clinton County, Kentucky, Terence Hamilton-Smith, Brandon C. Nuttall, Patrick J. Gooding, Dan Walker, James A. Drahovzal Jan 1990

High-Volume Oil Discovery In Clinton County, Kentucky, Terence Hamilton-Smith, Brandon C. Nuttall, Patrick J. Gooding, Dan Walker, James A. Drahovzal

Information Circular--KGS

The Syndicated Options Limited of Austria No. 9372 Ferguson Brothers well, located in southern Clinton County, Kentucky, has recently produced oil at reported initial rates of 400 to 130 barrels per hour. Cumulative production for the first 8 weeks of flow following discovery on September 25, 1990, is reported to be nearly 150,000 barrels. The well is the result of deepening a previously abandoned well. Production is from the Middle Ordovician High Bridge Group (equivalent to the Stones River Group of Tennessee) at a depth of 1,008 feet. The reservoir is apparently a fractured carbonate rock, and the fracturing is …


Constraints On The Emplacement And Uplift History Of The Pine Mountain Thrust Sheet, Eastern Kentucky: Evidence From Coal Rank Trends, Kieran D. O'Hara, James C. Hower, Susan M. Rimmer Jan 1990

Constraints On The Emplacement And Uplift History Of The Pine Mountain Thrust Sheet, Eastern Kentucky: Evidence From Coal Rank Trends, Kieran D. O'Hara, James C. Hower, Susan M. Rimmer

Earth and Environmental Sciences Faculty Publications

In this paper coal rank trends on both sides of the Pine Mountain thrust in eastern Kentucky are used to place constraints on thrust evolution. Vitrinite reflectance () measurements on a single Pennsylvanian coal horizon (Fire Clay coal) in eastern Kentucky increase from 0.5% in the north to about 1.0% toward the SE in front of the Pine Mountain thrust. The same horizon in the hangingwall of the thrust displays lower Rmax values (0.8-0.85%). The reflectance isograds are subparallel to the thrust within approximately 10 km of the trace of the fault. We attribute thermal maturation to (1) pre-orogenic …


The Geology Of Taconic Thrust Sheets And Surrounding Carbonates Of The West Central Vermont Marble Belt, North Of Rutland, Vermont, Kay Bierbrauer Jan 1990

The Geology Of Taconic Thrust Sheets And Surrounding Carbonates Of The West Central Vermont Marble Belt, North Of Rutland, Vermont, Kay Bierbrauer

Geology Theses and Dissertations

The carbonates of the Vermont Valley and the overlying rocks of the Taconic sequence have been generally believed to lie on the east limb of a major unfaulted syncline (Middlebury Synclinorium). In this view a westward dipping, north-south trending basal Taconic overthrust must be exposed somewhere along the eastern margin of the Taconic Range.
In contrast, this study based on detailed mapping at the north end of the Taconic Allochthon suggests that a folded overthrust surface is only locally seen in fensters; more commonly the basal obduction surface of the Taconic Allochthon has been truncated by later cross-cutting thrust faults. …


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 …


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 …


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 …


Geology And Structure Of The Rocks Associated With The Basal (Madstone) Thrust Of The Josephine Ophiolite In Southwestern Oregon: Evidence For A Metamorphic Sole, Kristin A. Grady Jan 1990

Geology And Structure Of The Rocks Associated With The Basal (Madstone) Thrust Of The Josephine Ophiolite In Southwestern Oregon: Evidence For A Metamorphic Sole, Kristin A. Grady

Geology Theses and Dissertations

Many ophiolites have amphibolite at their base which contains a sharp inverted grade of metamorphism. These metamorphic soles are thought to have formed during the detachment and emplacement of the ophiolite. In addition to the sharp inverted grade of metamorphism, other characteristics of metamorphic soles include 1). a highly strained peridotite unit of the hanging wall which has concordant structures with underlying amphibolite and 2). an underlying melange sequence and continental rocks.
The Madstone thrust displaces the Josephine peridotite (Josephine ophiolite-162 Ma) onto amphibolites and underlying deformed gabbros of the Chetco Intrusive Complex. The rocks associated with the Madstone thrust …


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 …


Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser Jan 1990

Lottery Proceeds In California Pay For Installation Of A Ground-Water Monitoring System, June Ann Oberdorfer, J. W. Williams, M. G. Smelser

Faculty Publications

No abstract provided.


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


Gravity Maps, Models And Analysis Of The Greater Portland Area, Oregon, Paul Thomas Beeson Jan 1990

Gravity Maps, Models And Analysis Of The Greater Portland Area, Oregon, Paul Thomas Beeson

Dissertations and Theses

Growing concern over earthquakes in the Pacific Northwest has prompted the mapping and location of near surface faults in the Portland area, Oregon. Visible evidence of faults is poor, requiring the use of geophysical methods to assist in mapping and defining structures in the basin. Gravity maps and models may help in addressing this problem.


Annual Report Of Nebraska-1990, Karl E. Starch, Raymond R. Burchett Jan 1990

Annual Report Of Nebraska-1990, Karl E. Starch, Raymond R. Burchett

Conservation and Survey Division

No abstract provided.


Richardson County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1990

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

Conservation and Survey Division

No abstract provided.


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

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

Conservation and Survey Division

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

No abstract provided.