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Articles 27661 - 27690 of 29955

Full-Text Articles in Geology

Fluvial Depositional Processes Of A Tropical River, Colombia, South America, Michael L. Babuin Apr 1985

Fluvial Depositional Processes Of A Tropical River, Colombia, South America, Michael L. Babuin

OES Theses and Dissertations

Fluvial depositional processes along the Rio Magui in south-western Columbia are primarily controlled by localized uplift downstream of the mouth of the river, sediment sources that produce both coarse-and-fine-grained load, and numerous over-bank flows caused by torrential rainfall.


A Geophysical Model Of The Gravity-Magnetic High, Virginia Coastal Plan, Gordon Everett Davison Apr 1985

A Geophysical Model Of The Gravity-Magnetic High, Virginia Coastal Plan, Gordon Everett Davison

OES Theses and Dissertations

The coastal plain province of Virginia is characterized by a coincidental gravity and magnetic high separating Appalachian-trend geophysical signatures to the west from non-Appalachian signatures to the east. Two cross-trend gravity and magnetic profiles, one on the Northern Neck of Virginia and one along Interstate Highway 64, were used to interpret the anomalous high. The profile models suggests that the anomaly is characterized by high-density, variably magnetic, east-dipping (60°) crustal blocks. Further information from well-logs indicate that the anomaly is due to meta-mafic rocks of oceanic origin, flanked by low-density, lower susceptibility, granitic units. This suggests that the anomalous gravity-magnetic …


Foraminiferal Paleoenvironments Of The Eastover Formation (Upper Miocene Virginia), Joann H. Goshorn Apr 1985

Foraminiferal Paleoenvironments Of The Eastover Formation (Upper Miocene Virginia), Joann H. Goshorn

OES Theses and Dissertations

Sixty-two taxa representing 29 genera from 39 foraminiferal sample pairs have been documented and analyzed in a paleoenvironmental study of the Eastover Formation in southeastern Virginia. The Eastover Formation consists of a lower Claremont Manor Member, a silt fine-grained sand and an upper Cobham Bay Member, a shelly fine grained sand. Planktonic specimens were rare and indicated a late Miocene to early Pliocene age for the Eastover Formation. Benthics were used to interpret paleoenvironments by comparison with data from the distribution of Recent foraminifera, species diversity, planktonic to benthic ratios, and sediment analyses. The foraminifera indicate that the Eastover Formation …


Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer Mar 1985

Uses And Abuses Of Wastewater Injection Wells In Hawaii, F. L. Peterson, June Ann Oberdorfer

Faculty Publications

During the past two decades in Hawaii, more than 500 injection wells for the disposal of domestic sewage wastewater have been constructed and operated. Thus far, contamination of potable groundwater supplies has not been a problem. Many of the injection wells, however, have not performed as designed, and aquifer clogging and reduced injection capacity have produced numerous well failures resulting in public health, legal, and financial problems. Factors most commonly responsible for the well problems have been unfavorable hydrogeology, underdesign of injection well capacity, poor effluent quality, and lack of injection well maintenance. Detailed study of clogging mechanisms in the …


Classification, Paleoecology, And Biostratigraphy Of Crinoids From The Stull Shale (Late Pennsylvanian) Of Nebraska, Kansas, And Iowa, Roger K. Pabian, Harrell L. Strimple Mar 1985

Classification, Paleoecology, And Biostratigraphy Of Crinoids From The Stull Shale (Late Pennsylvanian) Of Nebraska, Kansas, And Iowa, Roger K. Pabian, Harrell L. Strimple

Bulletin of the University of Nebraska State Museum (1924–2023)

Thirteen species of crinoids representing the families Diphuicrinidae, catacrinidae, Pirasocrinidae, Erisocrinidae, Cromyocrinidae, Cymbiocrinidae, Scytalocrinidae, and Ampelocrinidae have been collected from the Stull Shale Member of the Kanwaka Formation in the Shawnee Group of the Virgil Series (Upper Pennsylvanian) from near Weeping Water and Plattsmouth, Nebraska, and near Pacific Junction, Iowa. Exposures of the Stull Shale near Melvern, Kansas, have yielded 14 species of crinoids representing the families Diphuicrinidae, Catacrinidae, Pirasocrinidae, Lophocrinidae Allagecrinidae, Cymbiocrinidae, Erisocrinidae, Apographiocrinidae, and Stellarocrinidae. All but two of the species present in the Stull Shale have been previously reported from other stratigraphic horizons, including the Vinland Shale …


Geology And Structure Of Kodachrome Basin State Reserve And Vicinity, Kane And Garfield Counties, Utah, Dwight Hornbacher Mar 1985

Geology And Structure Of Kodachrome Basin State Reserve And Vicinity, Kane And Garfield Counties, Utah, Dwight Hornbacher

Loma Linda University Electronic Theses, Dissertations & Projects

In my efforts to discover source, time, and mechanism of formation of the clastic pipes and dikes found in the region of Kodachrome Basin State Reserve, I found it necessary to understand the depositional environments of the different members and formations within the study area. Mapping and study of the rock units of the Carmel, Entrada, Henrieville, and Tropic-Dakota formations and subsequent comparison with the interpretation of the depositional environments by others working in the same formations in the surrounding region suggest the following history.

The parallel-laminated, siliciclastic sediments and limestones of the Paria River Member of the Carmel Formation …


Flora Of The Lower Cretaceous Cedar Mountain Formation Of Utah And Colorado; Part Iii, Icacinoxylon Pittiense N. Sp., William D. Tidwell, Gregory F. Thayn, W. L. Stokes Feb 1985

Flora Of The Lower Cretaceous Cedar Mountain Formation Of Utah And Colorado; Part Iii, Icacinoxylon Pittiense N. Sp., William D. Tidwell, Gregory F. Thayn, W. L. Stokes

Faculty Publications

Icacinoxylon pittiense, a new species of angiospermous wood from the Lower Cretaceous Cedar Mountain Formation of Utah is described and compared with similar fossil and modern woods. It is distinguished from other species of Icacinoxylon by its thick-walled fiber-tracheids with their walls making up at least 50% of the total diameter of the cells, conspicuous bordered pits with obliquely crossing extended apertures on both the tangential and radial walls of its fiber-tracheids, scalariform perforation plates with as few as four or greater than 30 bars, transitional opposite to scalariform pitting on its vessel walls, thick-walled ray cells, and distinct sheath …


Cenozoic Paleogeography Of Western Nebraska, James B. Swinehart, Vernon F. Souders, Harold M. Degraw, Robert F. Diffendal Jr. Jan 1985

Cenozoic Paleogeography Of Western Nebraska, James B. Swinehart, Vernon F. Souders, Harold M. Degraw, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Cenozoic strata of western Nebraska are an extensive sequence of continental deposits that extend eastward from the Hartville, Laramie, and Front Range uplifts and southeast from the Black Hills. The oldest Cenozoic sediments (Chadron Formation, White River Group) are Early Oligocene alluvial valley fills. Subsequent to filling of these drainages and continuing for about the next 7 million years, landscape development in western Nebraska was dominated by eolian deposition of tremendous volumes of rhyolitic volcanic ash derived from western eruptions. A plain of low relief, with only an occasional narrow drainage heading in the western highlands, was maintained during …


The Continental Crust: Its Composition And Evolution, Stuart Ross Taylor, Scott M. Mclennan Jan 1985

The Continental Crust: Its Composition And Evolution, Stuart Ross Taylor, Scott M. Mclennan

Department of Geosciences Faculty Publications

Graduates in geology, geochemistry and geophysics will find this book a valuable reference text. The book begins by describing the known composition of the present upper crust, then deals with possible compositions for the total crust and the inferred composition of the lower crust. The question of the uniformity of crustal composition throughout geological time is discussed, the rate of growth of the crust and the effects of extraction of the crust on mantle compositions are considered. Finally, the question of early pre-geological crusts on Earth is debated and comparisons are given with crusts on the Moon, Mercury, Mars, Venus …


Preliminary Geologic Map Of The Nephi 30' By 60' Quadrangle, Carbon, Emery, Juab, Sanpete, Utah, And Wasatch Counties, Utah, United States Geological Survey Jan 1985

Preliminary Geologic Map Of The Nephi 30' By 60' Quadrangle, Carbon, Emery, Juab, Sanpete, Utah, And Wasatch Counties, Utah, United States Geological Survey

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

The U.S. Geological Survey is engaged in a program of field studies designed to present the geologic framework of the United States on easily read topographic maps. The maps selected as a base for these geologic data are part of the Army Map Service (AMS) series of 1° by 2° quadrangles at a scale of 1:250,000. The Price, Utah AMS 1:250,000 quadrangle is one of these maps (fig.1). For certain areas, however, chiefly those sectors of the country involved in the Geological Survey's coal exploration program, the geologic data are being compiled on newly developed base maps at a scale …


Bedrock Aquifers Of Eastern San Juan County, Utah, United States Geological Survey Jan 1985

Bedrock Aquifers Of Eastern San Juan County, Utah, United States Geological Survey

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

This study is one of a series of studies appraising the water-bearing properties of the Navajo Sandstone and associated formations in southern Utah. The study area is about 4,600 square miles, extending from the Utah-Arizona State line northward to the San Juan-Grand County line and westward from the Utah-Colorado State line to the longitude of about 109 degrees 50 minutes.


The Quaternary Bone Caves And Associated Sites At Wallingford, Jamaica, Donald A. Mcfarlane, R. E. Gledhill Jan 1985

The Quaternary Bone Caves And Associated Sites At Wallingford, Jamaica, Donald A. Mcfarlane, R. E. Gledhill

WM Keck Science Faculty Papers

A group of caves associated with the sink of the One Eye River in St. Elizabeth Parish, Jamaica, have been the subject of numerous important palaeontological investigations beginning 1919. Unfortunately, considerable confusion has arisen in the literature through inadequate documentation of different sites. The caves of the immediate area are described and located, and their palaeontological significance is summarised in the light of recent taxonomic review and relevant geochronological evidence.


Ua66/8/3 Annual Report, Wku Geography & Geology Jan 1985

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

WKU Administration Documents

Annual report created by and about WKU Geography & Geology for the school year 1984-1985.


Chemical Composition Of Ground Water In The Yucca Mountain Area, Nevada, 1971-84, Larry Benson, P. W. Mckinley Jan 1985

Chemical Composition Of Ground Water In The Yucca Mountain Area, Nevada, 1971-84, Larry Benson, P. W. Mckinley

United States Geological Survey: Publications

Fifteen test wells in the Yucca Mountain area of southern Nevada have been sampled for chemical analysis at least once during 1971-84. Samples were obtained by pumping water from the entire well bore (composite sample), and, in three instances, by pumping from one or more isolated intervals within a well bore. Sodium was the most abundant cation, and bicarbonate was the most abundant anion in all water samples. Samples from the deep carbonate aquifer penetrated by well UE-25p#l contained higher relative concentrations of calcium and magnesium than did samples from overlying volcanic tuffs. Concentrations of the stable isotopes of oxygen …


Sandplain Hardpan : A Different Dam Construction Material, A F. Mccrea Jan 1985

Sandplain Hardpan : A Different Dam Construction Material, A F. Mccrea

Journal of the Department of Agriculture, Western Australia, Series 4

Before 1980, the Department of Agriculture did not believe that suitable farm dam materials could be found in light land soils. However Beacon earthmoving contractor, V> J> Pavlinovich, has demonstrated that where suitable cemented subsoils or 'hardpan' existed, a succcessful dam site could be found.

This material should not be confused with compaction or traffic hardpans ehich are dense layers of soil found near the surface. Traffic hardpans result from compaction of soil materials with the passage of vehicles and farm machinery. Rather, the hardpan referred to here is a natural subsoil layer that has been cemented by silica and …


Depositional Environments And Petrology Of The Felix Coal Interval (Eocene), Powder River Basin, Wyoming, Peter D. Warwick Jan 1985

Depositional Environments And Petrology Of The Felix Coal Interval (Eocene), Powder River Basin, Wyoming, Peter D. Warwick

Theses and Dissertations--Earth and Environmental Sciences

A study of a 250 ft. (76.2 m) stratigraphic interval that includes the Eocene-age Felix coal of the Wasatch Formation was undertaken in the Powder River Basin of Wyoming to establish a depositional model based on the interrelations of coal-seam geometry, coal maceral composition, and spatial distribution of adjoining rocks. Regional cross sections and maps of major rock bodies were prepared from 147 measured stratigraphic sections and 56 geophysical logs. Trends in maceral and chemical properties within the Felix coal were identified from petrographic and geochemical analyses of 72 coal channel samples. The combined data sets indicate that the thickest …


The Holocene Carbonate Eolianites Of North Point And The Modern Marine Environments Between North Point And Cut Cay, Brian White, H. Allen Curran Jan 1985

The Holocene Carbonate Eolianites Of North Point And The Modern Marine Environments Between North Point And Cut Cay, Brian White, H. Allen Curran

Geosciences: Faculty Publications

The goals of this part of the field trip are to study the types of strata, sedimentary structures, trace fossils, and dune morphologies of the Holocene eolianites excellently exposed along the coasts of Rice Bay and North Point. We will show how eolian deposition of carbonate grains occurs and how dunes are initiated and evolve. Toward the end of this excursion, a short snorkel dive will be conducted in the shallow, sheltered waters between North Point and Cut Cay to study grass beds, sandy substrates, and hardgrounds and to compare their associated sediments, plants, and animals. The area to be …


Atlas Illustrating The Characteristics Of Groundwater In Nebraska, Vince Dreeszen Jan 1985

Atlas Illustrating The Characteristics Of Groundwater In Nebraska, Vince Dreeszen

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Metamorphism And Migmatization Of Metasediments In The Precambrian English River Subprovince, Western Ontario, Rodney M. Baumann Jan 1985

Metamorphism And Migmatization Of Metasediments In The Precambrian English River Subprovince, Western Ontario, Rodney M. Baumann

Theses and Dissertations

Metasediments of the Precambrian English River subprovince, a subdivision of the Superior province, are conspicuously migmatized by 'bands of light-colored, igneous-appearing material. The metasediments themselves consist of alternating layers of pelite and wacke lithologies, which represent original mudstones and graywackes respectively. Their deposition is thought to represent subaqueous turbidity flows.

For the metasediments of the study area, a 250 square kilometer portion of the English River subprovince, metamorphic grade increases southward from the English River subprovince's northern border. Two isograds have been mapped: the disappearance of muscovite and the disappearance of stable sillimanite. Geothermometry studies are consistent with the trend …


Middle And Late Wisconsinan (Pleistocene) Insect Assemblages From Illinois, Kristine D. Carter Jan 1985

Middle And Late Wisconsinan (Pleistocene) Insect Assemblages From Illinois, Kristine D. Carter

Theses and Dissertations

Two highly organic sediment sequences from central and western Illinois (the Athens North Quarry and Biggsville sites, respectively) of Middle and Late Wisconsinan age were studied to gain knowledge about the environment and climate of this area during the time immediately prior to the maximum extent of the last glaciation. Paleoenvironmental and paleoclimatic inferences are based principally upon knowledge of the habitat preferences and geographic distributions of extant species of beetles that are represented as fossils. These data are supplemented by information from sedimentological and taphonomic studies and from previously published palynological and plant-macrofossil studies.

The Athens North Quarry site …


Petrology Of The Sentinel Butte Formation (Paleocene), North Dakota, Nels F. Forsman Jan 1985

Petrology Of The Sentinel Butte Formation (Paleocene), North Dakota, Nels F. Forsman

Theses and Dissertations

Sedimentary materials of the Sentinel Butte Formation have been petrographically examined using optical and scanning electron micro scope/microprobe techniques. The formation consists of fine-grained materials which generally are classified mineralogically as volcanic litharenites or feldspathic litharenites. Most rock units in the formation are siltstones and mudstones. Multiple source rock types, including volcanic, metamorphic, and sedimentary, are represented by mineralogic constituents, but volcanic rock fragments are most abundant. Petrographic distinctions between basal and uppermost sandstone units suggest that a change in sediment supply took place near the end of Sentinel Butte time. Authigenic cement development appears concentrated in more porous and …


A Quantitative Analysis Of Shoreline Erosion Processes, Lake Sakakawea, North Dakota, Mark D. Millsop Jan 1985

A Quantitative Analysis Of Shoreline Erosion Processes, Lake Sakakawea, North Dakota, Mark D. Millsop

Theses and Dissertations

Shoreline erosion is a problem at Lake Sakakawea and Lake Audubon, North Dakota. Land is lost, water quality is adversely affected, and reservoir storage capacity is decreased.

Instrumentation of the eastern shores of both lakes began in 1983 to quantify bank erosion by process (e.g., wave erosion, rainsplash and runoff, and frost-thaw failure). Other data gathered included: pool level fluctuations; wind velocity, direction, and duration; precipita tion; soil moisture; frost penetration; freeze-thaw cycles; and geology (e.g., texture, clay mineralogy and structure).

The magnitude of shoreline erosion is highly variable, especially within Lake Sakakawea. For the interval of May 1983 through …


Geochemistry And Petrology Of The Lake Vermilion Formation, Ely Greenstone Belt, Northeastern Minnesota, Scott E. Robinson Jan 1985

Geochemistry And Petrology Of The Lake Vermilion Formation, Ely Greenstone Belt, Northeastern Minnesota, Scott E. Robinson

Theses and Dissertations

Alteration in the Lake Vermilion Formation took place at low water/rock ratios. Calculations using the method of Grescens (1967) indicate that the amount of open-system elemental exchange was slight. During secondary alteration, Ca, Na, K, Rb, Sr, and Ba were very mobile; Mg and Fe were less mobile; Si, Al, Ti, Zr, Y, and Ni were slightly mobile. Chemically the rocks resemble modern spilites and keratophyres.

The dacites and basalts are depleted in Ti, Zr, and Y relative to Tertiary igneous rocks of similar composition. The Lake Vermilion Formation basalts display a volcanic arc basalt trend of constant Ti02 with …


Sedimentology And Tectonic Significance Of The Nutzotin Mountains Sequence, Alaska, Jane Kozinski Jan 1985

Sedimentology And Tectonic Significance Of The Nutzotin Mountains Sequence, Alaska, Jane Kozinski

Geology Theses and Dissertations

The Nutzotin Mountains Sequence, a Mesozoic flysch sequence in the eastern Alaska Range, was studied along the southern border and in the central portions of the outcrop belt. Three lithologic associations are recognized in the Bonanza Creek section (southern margin) that together indicate a coarsening-upward trend, suggestive of a prograding fan system. These associations are (from bottom to top): 1) debris flow conglomerates overlain by 500 m of intercalated mudstone and base-missing turbiditic siltstone, and mass movement features such as slump folds and slump horizons, 2) 195 m of thicker, coarser turbidites intercalated with mudstones; turbidites are graded but lack …


Geology Of The Frozen Ocean Lake - New Bay Pond Area, North-Central Newfoundland, Timothy M. Kusky Jan 1985

Geology Of The Frozen Ocean Lake - New Bay Pond Area, North-Central Newfoundland, Timothy M. Kusky

Geology Theses and Dissertations

Rocks of the Frozen Ocean Group outcrop in the Frozen Ocean Lake-New Bay Pond Area, Newfoundland, and are here divided into four formations. The Lewis Lake Formation forms the base of the Frozen Ocean Group, and is composed predominantly of mafic volcanic flows; this is conformably overlain by the Blue Star Formation which is entirely sedimentary in nature. The Blue Star Formation is in turn conformably overlain.by the Bursey Point Formation, which is a mixed volcanic and sedimentary unit. The top of the Frozen Ocean Group is marked by the Lynx Pond Formation, a mixed silicic- and mafic-volcanic formation, with …


Stratigraphy And Structure Of The Ganson Hill Area: Northern Taconic Allochthon, Michelle Aparisi Jan 1985

Stratigraphy And Structure Of The Ganson Hill Area: Northern Taconic Allochthon, Michelle Aparisi

Geology Theses and Dissertations

The Ganson Hill study area is located in the Giddings Brook Slice of the Taconic Allochthon. It contains rocks of Cambrian(?), Cambrian and Ordovician age. The predominant rock type is slate with subordinate lithologies including quartzite, limestone, micrite, arenite and graywacke. The lithostratigraphy identified in the Ganson Hill area extends from the basal Bomoseen wacke to the Poultney slate. A more precisely defined lithostratigraphy is derived from the study area by the occurrence and recognition of the Middle Granville Slate Formation and the documentation of a second Cambrian black/green boundary. Previous workers have included this formation in different places, in …


Caves And Karst Of Kentucky, Percy H. Dougherty Jan 1985

Caves And Karst Of Kentucky, Percy H. Dougherty

Special Publication--KGS

Published in cooperation with the National Speleological Society. Includes an overview of Kentucky geology, karst, cave development, list of caves including Mammoth Cave and Carter Caves, historical caves, archaeology, and cave life of Kentucky.


Annual Outflow Of Water From Nebraska, 1950-1984, Conservation Survey Division Jan 1985

Annual Outflow Of Water From Nebraska, 1950-1984, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Estimate Of Self-Supplied Domestic Water Use In Nebraska During 1980, E.K. Steele Jan 1985

Estimate Of Self-Supplied Domestic Water Use In Nebraska During 1980, E.K. Steele

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Nebraska Mineral Operations Review, 1984, Raymond R. Burchett, Duane A. Eversoll Jan 1985

Nebraska Mineral Operations Review, 1984, Raymond R. Burchett, Duane A. Eversoll

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.