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Articles 27481 - 27510 of 29955

Full-Text Articles in Geology

Benthic Foraminiferal Assemblages From Mexican Continental Shelves, Maria De La Luz Mata Apr 1987

Benthic Foraminiferal Assemblages From Mexican Continental Shelves, Maria De La Luz Mata

LSU Historical Dissertations and Theses

The recent benthic foraminifera 1 fauna of the continental margins of Mexico (Gulf of Campeche and Gulf of Tehuantepec) was studied. Surficial sediment samples (lOcc) were collected using a Shipeck dredge and were stained with Sudan Black "B" in order to differentiate the living fauna from the death assemblage. In the 41 samples from the Gulf of Campeche, 279 species were found in the total assemblage in water depths ranging from 9 to 586 m. In the 22 samples in the Gulf of Tehuantepec, 132 species were identified from the total assemblage in water depths of 20 to 180 m. …


Rheologic Properties And Kinematics Of Emplacement Of The Chaos Jumbles Rockfall Avalanche, Lassen Volcanic National Park, California, Dean B. Eppler, Jonathan H. Fink, Raymond Fletcher Apr 1987

Rheologic Properties And Kinematics Of Emplacement Of The Chaos Jumbles Rockfall Avalanche, Lassen Volcanic National Park, California, Dean B. Eppler, Jonathan H. Fink, Raymond Fletcher

Geology Faculty Publications and Presentations

The Chaos Jumbles is a rockfall avalanche deposit that was emplaced by three separate events ~ 300 years ago. Deposits from each event are distinguishable on the basis of morphology, size variation of large dacitic surface clasts, and by the color of both the matrix and entrained dacitic blocks. Steep lateral and distal deposit margins and surface features such as folds and apparent strike-slip faults indicate that each rockfall avalanche had a finite yield strength and was being actively deformed and sheared throughout the body of the moving deposit, rather than strictly along a basal surface. Kinematic analysis of the …


The Effect Of Well Efficiency On In-Situ Permeability Test Results, Scott T. Dennis Apr 1987

The Effect Of Well Efficiency On In-Situ Permeability Test Results, Scott T. Dennis

Masters Theses

The purpose of this study was to determine what effect well efficiency has upon the results of in-situ permeability tests.

Several in-situ permeability tests were performed on wells during various stages of their development. The well efficiency was determined each time an in-situ test was performed. An accurate value of permeability was determined by performing local aquifer pumping tests. The accuracy of the results of the in-situ tests with respect to the aquifer pump test results were then compared to the efficiency of the well at the time of the test.

Test results showed that a linear relationship exists between …


Yellowstone National Park: The Oberlin Connection, Allen Memorial Art Museum, Oberlin College Library Apr 1987

Yellowstone National Park: The Oberlin Connection, Allen Memorial Art Museum, Oberlin College Library

Exhibition Catalogs

Exhibition Dates: April 15 to June 15, 1987
An exhibition examining the connection between Oberlin and the early exploration of Yellowstone National Park, including Oberlinians General Henry D. Washburn and geologist Ferdinand V. Hayden.


The Stratigraphy Of Late Quaternary Deposits In The Payan Mining District, Narino, Colombia, South America, Richard Alan Barringer Apr 1987

The Stratigraphy Of Late Quaternary Deposits In The Payan Mining District, Narino, Colombia, South America, Richard Alan Barringer

OES Theses and Dissertations

Late Quaternary terrace deposits along the Rio Magui consist of cobble or pebble gravels with thick volcanic ash caps. These gravel terrace deposits unconformably overlie a cemented volcanic tuff (Ananias Formation), and are subdivided into two formations (Antigua and Panambi formations) based on the cobble lithology and size, depth of weathering, geomorphic relationships, and heavy mineral assemblages. Carbon-14 dates from wood suggest that the Antigua fan deposits are older (greater than 40,000 YBP) than the lower Panambi alluvium (less tahn 25,000 YBP) which is restricted to lower terraces within the modern river valleys.

Two separate ash units identified by differences …


Provenance Of Sands Within The Lower Chesapeake Bay Based On Ilmenite Composition, Edward Augustus Council Iii Apr 1987

Provenance Of Sands Within The Lower Chesapeake Bay Based On Ilmenite Composition, Edward Augustus Council Iii

OES Theses and Dissertations

Surficial sands deposited in the Chesapeake Bay are a mixture of sands derived from the bay's shorelines, from offshore, and from relict deposits. Direct fluvial input is probably minor except from the James River, which may serve as a local source of sands in the Thimble Shoals area. Sands in the western half of the bay are primarily derived from the erosion of the adjacent shoreline. In contrast, the eastern half of the bay has two major sources of sand. Shoreline erosion is the dominant source north of the town of Eastville, Virginia, while the offshore is the major source …


Structural Geology And Geothermal Investigation Of The White Sulphur Springs Area, Montana, William G. Gierke Apr 1987

Structural Geology And Geothermal Investigation Of The White Sulphur Springs Area, Montana, William G. Gierke

Masters Theses

Sevier thrusting in the White Sulphur Springs area was associated with left-lateral movement along the Lewis and Clark line . During Middle Miocene time, the Lewis and Clark line exhibited right-lateral movement, forming extensional features that either truncated Sevier structures or followed preexisting Sevier zones of weakness.

The Smith River Valley is a pull-apart basin that is filled with Tertiary volcanic ash and clay-rich sediments that are thermally nonconductive relative to surrounding rocks.

Hydrothermal activity in the area is associated with a structurally controlled circulation system accompanied by a high thermal gradient. Thermal discharge is constrained along the north-trending White …


Duer Ranch, Morrill County, Nebraska: Contrast Between Cenozoic Fluvial And Eolian Deposition, James B. Swinehart, R. F. Diffendal Jr. Jan 1987

Duer Ranch, Morrill County, Nebraska: Contrast Between Cenozoic Fluvial And Eolian Deposition, James B. Swinehart, R. F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Duer Ranch locality contains some of the finest and most easily accessible examples of different styles of alluvial cuts and fills in the Cenozoic rocks of Nebraska. It offers a unique area in which to examine the geometries and alluvial fills of several Miocene and Pliocene age paleovalleys and paleo-gullies. Good exposures of eolian volcaniclastic siltstones and a regionally important volcanic ash of the Oligocene age Brule Formation are also present at the Duer Ranch locality. In addition, Quaternary ephemeral stream development and deposits can be studied.

Location and Accessibility

Significance of the Locality

Locality Information

Measured Sections [I-IV] …


Paleohydrology Of Some Ogallala (Neogene) Streams In The Southern Panhandle Of Nebraska, R. G. Goodwin, Robert F. Diffendal Jr. Jan 1987

Paleohydrology Of Some Ogallala (Neogene) Streams In The Southern Panhandle Of Nebraska, R. G. Goodwin, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Stratification and estimated paleoflow conditions for valley-fill deposits suggest that Ogallala Group streams in western Nebraska were similar to modern streams of south-central Alberta.

Ogallala stratification includes medium-scale (0.5 to 2.0 m thick) trough crossbedded sand and gravel, tabular indistinctly horizontally bedded and imbricated gravel, and horizontally bedded sand and pebbly sand. Valley fills are 15 to 55 m thick and 800 to 1800 m wide at the top. Some are in bedrock-floored channels resembling the “inner channels” of Shepherd and Schumm (1974).

Gradients for three well exposed paleovalley floors range from 0.0014 to 0.0020 (m/m) after tectonic correction. This …


Lithologic Controls On Karst Groundwater Flow, Lost River Groundwater Basin, Warren County, Kentucky, Christopher Groves Jan 1987

Lithologic Controls On Karst Groundwater Flow, Lost River Groundwater Basin, Warren County, Kentucky, Christopher Groves

Masters Theses & Specialist Projects

The Lost River Groundwater Drainage Basin in Warren County, Kentucky, is a karst drainage system encompassing 55 square miles (143 square kilometers) developed within the Mississippian St. Louis and Ste. Genevieve Limestones. Near the contact between these two formations are two bedded chert units, the Lost River Chert Bed (Elrod, 1899) within the Ste. Genevieve and the Corydon Chert Member (Woodson, 1983) of the St. Louis, which appear to be perching layers to shallow karst groundwater flow. Groundwater may be seen flowing on top of these beds in various cave streams and at swallets and springs throughout the basin.

In …


Analysis Of Coal Samples From The Hazard District, Kentucky (Breathitt, Knott, Leslie, And Perry Counties And Other Parts Of Letcher And Harlan Counties), James C. Currens, Linda Jean Bragg, James C. Hower Jan 1987

Analysis Of Coal Samples From The Hazard District, Kentucky (Breathitt, Knott, Leslie, And Perry Counties And Other Parts Of Letcher And Harlan Counties), James C. Currens, Linda Jean Bragg, James C. Hower

Information Circular--KGS

Chemical and petrographic doto ore presented for 132 samples of cool collected in the Hazard District, eastern Kentucky. These data include sample-site locations, sampling conditions, stratigraphic position, megoscopic description of the cool, air-drying loss, proximate and ultimate analyses, Btu content, forms of sulfur, initial deformation temperature, softening temperature, fluid temperature, free-swelling index, concentration of major, minor, and trace elements, and petrographic analyses.


Analysis Of Coal Samples From Licking River District, Kentucky (Elliott, Magoffin, Morgan, And Wolfe Counties And Parts Of Menifee, Powell, And Rowan Counties), James C. Currens, Linda Jean Bragg, James C. Hower Jan 1987

Analysis Of Coal Samples From Licking River District, Kentucky (Elliott, Magoffin, Morgan, And Wolfe Counties And Parts Of Menifee, Powell, And Rowan Counties), James C. Currens, Linda Jean Bragg, James C. Hower

Information Circular--KGS

Chemical and petrographic data ore presented for 41 samples of cool collected in the Licking River District, eastern Kentucky. These data include sample-site locations, sampling conditions, stratigraphic position, megoscopic description of the cool, air-drying loss, proximate and ultimate analyses, Btu content, forms of sulfur, initial deformation temperature, softening temperature, fluid temperature, free-swelling index, concentration of major- and minor-oxides and trace elements, and petrographic analyses.


Geology And Mining Industry Of The Tintic District, Utah, George Warren Tower, Jr., George Otis Smith Jan 1987

Geology And Mining Industry Of The Tintic District, Utah, George Warren Tower, Jr., George Otis Smith

All U.S. Government Documents (Utah Regional Depository)

The field work upon which this report is based was begun in July, 1897, and continued without interruption until December of the same year. The area studied is approximated 15 miles square and contains 234 square miles. The topographic maps, which are two in number, were prepared under the direction of Mr. R. U. Goode, Mr. S. S. Gannett doing the triangulation and Messrs. Marshall and Griswold the topography in the fall of 1896 and summer of 1897. The mapping is done on two scales; the larger area, approximately 15 miles square, is mapped on a scale of 1:62,500. This …


An Inventory And Condition Survey Of Rangelands In The Carnarvon Basin, Western Australia, A L. Payne, G F. Spencer, P J. Curry Jan 1987

An Inventory And Condition Survey Of Rangelands In The Carnarvon Basin, Western Australia, A L. Payne, G F. Spencer, P J. Curry

Technical Bulletins

The inventory and condition survey of rangelands in the Carnarvon Basin, undertaken by the Department of Agriculture and Food, Western Australia (DAFWA) between 1980 and 1982, describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The area surveyed covers …


Ua66/8/3 Annual Report, Wku Geography & Geology Jan 1987

Ua66/8/3 Annual Report, Wku Geography & Geology

WKU Administration Documents

Annual report created by and about WKU Geography & Geology. Table of contents is mis-numbered.


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 …


Trace Fossils In Carbonate Upper Beach Rocks And Eolianites: Recognition Of The Backshore To Dune Transition, H. Allen Curran, Brian White Jan 1987

Trace Fossils In Carbonate Upper Beach Rocks And Eolianites: Recognition Of The Backshore To Dune Transition, H. Allen Curran, Brian White

Geosciences: Faculty Publications

Reprinted from: H. Allen Curran (ed.), Proceedings of the Third Symposium on the Geology of the Bahamas: Fort Lauderdale, Florida, CCFL Bahamian Field Station


Late Cenozoic Geology Along The Summit To Museum Hiking Trail, Scotts Bluff National Monument, Western Nebraska, J. B. Swinehart, D. B. Loope Jan 1987

Late Cenozoic Geology Along The Summit To Museum Hiking Trail, Scotts Bluff National Monument, Western Nebraska, J. B. Swinehart, D. B. Loope

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


A Hydrogeologic Study Of The Local Groundwater Flow System At Osmond, Ne, Jonathan Alix Jan 1987

A Hydrogeologic Study Of The Local Groundwater Flow System At Osmond, Ne, Jonathan Alix

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Resource Notes-Fall/Winter 1986-87 Jan 1987

Resource Notes-Fall/Winter 1986-87

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 1985)/Registered Irrigation Wells In Nebraska (As Of January 1, 1986), Conservation Survey Division, U.S. Geological Survey Jan 1987

Significant Rises And Declines In Nebraska Groundwater Levels (From Pre-Development As Of Fall 1985)/Registered Irrigation Wells In Nebraska (As Of January 1, 1986), Conservation Survey Division, U.S. Geological Survey

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Metamorphism In The Wabigoon Subprovince In The Vicinity Of Vermilion Bay And Sioux Lookout, Ontario, Christine K. Roob Jan 1987

Metamorphism In The Wabigoon Subprovince In The Vicinity Of Vermilion Bay And Sioux Lookout, Ontario, Christine K. Roob

Theses and Dissertations

The Wabigoon-English River subprovince boundary has been proposed by various workers to be either a fault, an unconformity, an intrusive contact or a gradational boundary. North of the Wabigoon Fault, in the Vermilion Bay-Dryden area, migmatization and partial melting of meta sediments have produced a variety of metatexitic and diatexitic migmatites. Because migmatites are not encountered in the Wabigoon subprovince proper and the area north of the Wabigoon fault is so different from the rest of the subprovince, it is thought that the area may constitute the southernmost part of the English River sub province.

The Wabigoon Subprovince is a …


The Providence Island Formation In The Northern Appalachian Region - A Lower-Lower Middle Ordovician Analogue To Recent Arid-Semiarid Tidal-Flat Carbonates Of The Persian Gulf Trucial Coast, Mauricio Roma Hernandez Jan 1987

The Providence Island Formation In The Northern Appalachian Region - A Lower-Lower Middle Ordovician Analogue To Recent Arid-Semiarid Tidal-Flat Carbonates Of The Persian Gulf Trucial Coast, Mauricio Roma Hernandez

Geology Theses and Dissertations

The Providence Island Formation of Early-early Middle Ordovician age occurs in the Champlain Valley and adjacent areas in eastern New York, western Vermont, and southern Quebec. The unit forms part of a carbonate shelf sequence which occupied the eastern margin of the North American continent from Newfoundland to Alabama, and its lithology is representative of the dolostone lithofacies that characterizes the uppermost Beekmantown Group in this region.
This is the first study documenting depositional environments, diagenesis, and stratigraphic correlations of the Providence Island Formation. This formation consists, in decreasing abundance, of dolostones, limestones, shales, and dedolostones. The dominantly fine grain …


Structural Investigations On Experimentally And Naturally Produced Slickensides, Thomas Michael Will Jan 1987

Structural Investigations On Experimentally And Naturally Produced Slickensides, Thomas Michael Will

Geology Theses and Dissertations

This work has involved an experimental approach and a study of naturally produced slickensides.
The experiments, carried out on a pyrophyllitic rock, have been performed in order to define some extrinsic parameters that control surface and microstructural features. Normal stress, speed (i.e. strain rate), and amount of slip and total displacement were related to measureable surface features, such as length, and spacing between the developing ridges and grooves. Special attention was paid to a newly recognized type of slickenside lineation (Means, 1986). This lineation produced experimentally cannot be explained in terms of the traditional asperity ploughing or dissolution/precipitation models. It …


Petrology Of The Kula Volcanic Field, Western Turkey, Julie M. Dyer Jan 1987

Petrology Of The Kula Volcanic Field, Western Turkey, Julie M. Dyer

Geology Theses and Dissertations

The Kula volcanics are a small Pleistocene to Recent volcanic field located on the north shoulder of the Gediz graben, approximately 120 km east of Izmir. The field consists of a mixture of flows, small cones and pyroclastic deposits erupted during three periods of volcanic activity beginning about one million years ago. The volcanics range in composition from basanites to trachybasalts, commonly porphyritic with abundant clinopyroxene, olivine and amphibole phenocrysts. The lavas also host a wide variety of megacrysts, crustal xenoliths and hydrous mantle-derived nodules. These volcanics unconformably overlie Neogene lacustrine sedimentary rocks and the metamorphic basement rocks of the …


Structural Analysis Across The Northeast Boundary Of The Taconic Allochthon, West-Central Vermont, Thomas E. Hoak Jan 1987

Structural Analysis Across The Northeast Boundary Of The Taconic Allochthon, West-Central Vermont, Thomas E. Hoak

Geology Theses and Dissertations

The Taconic Allochthon is an elongate belt of Cambro-Ordovician, argillaceous sediments with lesser occurrences of calcareous and siliceous lithologies. These lithologically distinctive strata lie tectonically juxtaposed over a coeval medial-Ordovician carbonate shelf sequence. This geometry resulted from an arc-continent collision in which a westward-migrating arc (Ammonoosuc Volcanics) collided with an eastern North America passive margin and the accumulated accretionary prism of the forearc region was thrust onto the passive continental margin.
The present thesis examined the structural sequence at the north end of the Allochthon and the continuity of this sequence into the adjacent Parautochthonous Shelf strata. Structurally, the study …


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 …


Geology Of The Northern Baie Verte Peninsula, Newfoundland, Canada, Pamela J. Stella Jan 1987

Geology Of The Northern Baie Verte Peninsula, Newfoundland, Canada, Pamela J. Stella

Geology Theses and Dissertations

On the eastern portion of the Burlington Peninsula of northwest central Newfoundland, Canada, there are two different age groups of volcanic and volcaniclastic rocks. There have been arguments in the past as to whether or not these two groups are actually only one group (Cape St. John Group) but with progressive intensity of deformation and metamorphism from south to north. Other workers have divided the rocks into two distinct groups, the Grand Cove Group and the Cape St. John Group based on their differences in deformation style and metamorphic grade. This study ignored previous divisions of the rocks into one …