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Articles 27751 - 27780 of 29955

Full-Text Articles in Geology

Sources Of Lime In The South-West, I M V Brown Jan 1984

Sources Of Lime In The South-West, I M V Brown

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

Many Western Australian farmers topdress or incorporate lime into their acid soils to neutralise them and to improve crop or pasture yields. Most use pulverised limestone or limesand which is cheap and relatively easy tospread.

Agricultural lime isdefined as "any fertiliser used principally for the purpose of reducing soil acidity and having calcium carbonate or magnesium carbonate, or both, as its main ingredients".

Less extensive sources of liming material are found in scattered inland areas where deposits of calcrete have been formed by the weathering of calcium-rich rock and also in association with internal drainage systems.

Magnesite, generally formed by …


Field Guide To The Cockburn Town Fossil Coral Reef, San Salvador, Bahamas, H. Allen Curran, Brian White Jan 1984

Field Guide To The Cockburn Town Fossil Coral Reef, San Salvador, Bahamas, H. Allen Curran, Brian White

Geosciences: Faculty Publications

James W. Teeter (ed.), 1984, Proceedings of the 2nd Symposium on the Geology of the Bahamas:San Salvador, CCFL Bahamian Field Station


Igneous Dikes At Long Valley, Ca: Emplacement Mechanisms And Associated Geologic Structures, David D. Pollard, Jonathan H. Fink, Paul T. Delaney Jan 1984

Igneous Dikes At Long Valley, Ca: Emplacement Mechanisms And Associated Geologic Structures, David D. Pollard, Jonathan H. Fink, Paul T. Delaney

Geology Faculty Publications and Presentations

Two hypotheses for dike emplacement are: (1) magma flows into and dilates pre-existing fractures; or (2) magma flows into and dilates self-generated fractures. In the first case dikes should be parallel to an element of the rock fabric; in the second, they should be perpendicular to the least compressive stress. The two hypotheses suggest different dike intrusion and fissure eruption mechanisms and therefore different strategies for monitoring igneous events at Long Valley. We derive a method to distinguish the two mechanisms, a priori, from in-situ stress measurements and estimates of magma pressure. Estimates of relative dilation and slip across a …


Trace-Elements In Ilmenite - A Way To Discriminate Provenance Or Age In Coastal Sands, Dennis A. Darby Jan 1984

Trace-Elements In Ilmenite - A Way To Discriminate Provenance Or Age In Coastal Sands, Dennis A. Darby

OES Faculty Publications

Trace elements and Ti percentage in ilmenite grains magnetically separated from modern and late Pleistocene coastal sands of southeastern Virginia and northwestern North Carolina were used to distinguish different deposits. Multivariate analysis of ilmenite composition (Ti, Mn, Mg, Cr, V, Ni, and Cu) from coastal deposits and potential source rivers enabled the identification of dominant source rivers. Using the trace element content of one mineral instead of heavy-mineral suites eliminated most of the hydraulic sorting, selective weathering, and intrastratal solution problems that often obscure heavy-mineral provenance determinations. Most ilmenite grains lacked exsolution or twinning, which are common to ilmenite; however, …


Stratigraphy And Depositional Environments Of The Three Forks Formation (Upper Devonian), Williston Basin, North Dakota, Gayle M. Dumonceaux Jan 1984

Stratigraphy And Depositional Environments Of The Three Forks Formation (Upper Devonian), Williston Basin, North Dakota, Gayle M. Dumonceaux

Theses and Dissertations

The Three Forks Formation (Upper Devonian) is present in the subsurface in the western two-thirds of North Dakota and is generally conformable with the underlying Birdbear Formation and the overlying Bakken Formation.

The Three Forks attains a maximum thickness of 265 feet (81 meters) in the central basin, east and south of the Nesson Anticline, and thins to an erosional edge in eastern North Dakota. The Three Forks is composed of micrite and dolomicrite, which may be fcssiliferous and argillaceous. From the study of core samples and detailed petrographic analysis of thin sections, five lithofacies were recognized and their extent …


Bivalve Associations Of The Cannonball Formation (Paleocene, Danian) Of North Dakota, Rosanne M. Lindholm Jan 1984

Bivalve Associations Of The Cannonball Formation (Paleocene, Danian) Of North Dakota, Rosanne M. Lindholm

Theses and Dissertations

The Cannonball Formation (Paleocene, Danian) is best exposed in southwest-central North Dakota. Here, two major lithotypes, mudstone and sandstone, occur. In this area, the Cannonball can be informally subdivided into four lithologic units: lower (primarily thinly-bedded sandstone and mudstone), lower-middle (sandstone), upper-middle (mudstone), and upper (sandstone). The Cannonball is also exposed in southwestern North Dakota where it occurs as two mudstone tongues (upper and lower).

During July and August, 1982, thirteen Cannonball outcrops were studied. Bivalves, along with other macrofossils, were collected quantitatively in an attempt to determine fossil species dominance. Rock samples were also collected and analyzed for textural …


The Geochemical Evolution Of Saline Groundwater Within A Fresh Water Aquifer South Of Oakes, North Dakota, David L. Williams Jan 1984

The Geochemical Evolution Of Saline Groundwater Within A Fresh Water Aquifer South Of Oakes, North Dakota, David L. Williams

Theses and Dissertations

An area of saline/brackish groundwater south of Oakes, North Dakota has been reported by the North Dakota State Water Commission. The concentrated water (over 12,000 mg/L of total dissolved solids) is in direct hydraulic connection with relatively fresh water and shows an abrupt change in concentration and water chemistry between these two end members. The saline/brackish water is beneath a shallow trough or depression which has an approximate area of 6 square miles (15.5 square kilometres). The trough is within the northern part of the Glacial Lake Dakota plain. Sediments in the lake plain, which is an unconfined aquifer, are …


Depositional Environments And History Of The Winnipeg Group (Ordovician), Williston Basin, North Dakota, Stephen C. Thompson Jan 1984

Depositional Environments And History Of The Winnipeg Group (Ordovician), Williston Basin, North Dakota, Stephen C. Thompson

Theses and Dissertations

The Winnipeg Group (Ordovician) in the Williston Basin, North Dakota, contains three formations. They are, in ascending order, the Black Island Formation, herein informally divided into lower and upper members, the Icebox Formation, and the Roughlock Formation. Strata of the Winnipeg Group (maximum thickness 400 ft., 122 m) represent the initial deposits of a Middle Ordovician craton-wide transgression. Throughout most of North Dakota, the Winnipeg is unconformably underlain by the Deadwood Formation (Upper Cambrian-Lower Ordovician) and conformably overlain by the Red River Formation (Upper Ordovician).

The strata of the lower member of the Black Island Formation consist of a red-bed …


Fission Track Dating Of Detrital Zircons From The Scotland Sandstones, Barbados, West Indies, Suzanne Louise Baldwin Jan 1984

Fission Track Dating Of Detrital Zircons From The Scotland Sandstones, Barbados, West Indies, Suzanne Louise Baldwin

Geology Theses and Dissertations

Results of fission track dating of detrital zircons from the Scotland sandstones, Barbados, yield a mixture of ages with several strong groupings from 20-80 Ma, 200-350 Ma, and greater than 500 Ma. Metamict grains were assumed to fall into the greater than 500 Ma population.
The youngest population indicates that the Scotland beds, previously dated by paleontologic methods as Eocene, may actually be as young as late Oligocene. These ages better constrain the timing of deposition for these sediments and support the proposal that the late middle Eocene - early Oligocene Oceanic Fm has overthrust the Scotland beds. This population …


The Tectonic Evolution Of The Eastern Yukon Tanana Upland, Alaska, Grant W. Cushing Jan 1984

The Tectonic Evolution Of The Eastern Yukon Tanana Upland, Alaska, Grant W. Cushing

Geology Theses and Dissertations

Field, structural, and isotopic studies in the southeastern Eagle Quadrangle reveal a complex Mesozoic history involving major metamorphism, fold development, thrusting, and igneous intrusion. These events may be related to the accretion of a terrane, possibly Stikine, to the North American continental margin.
40Ar/39Ar incremental heating experiments on metamorphic minerals from amphibolite facies rocks reveal Late Triassic to Middle Jurassic plateau ages interpreted as the age of major metamorphism. Large scale northeast trending folds within these rocks formed after the major metamorphism and before the intrusion of an undeformed, unmetamorphosed cross-cutting dike in Middle Jurassic. These folds probably developed in …


The Geology Of Ophiolitic And Adjoining Rocks Of Chagnon Mountain, Southern Quebec, Janet M. Harris Jan 1984

The Geology Of Ophiolitic And Adjoining Rocks Of Chagnon Mountain, Southern Quebec, Janet M. Harris

Geology Theses and Dissertations

Chagnon Mountain is located near the southern end of the Baie Verte-Brompton Line in the Eastern Townships of southern Quebec. The lithologic units in the area of study, from west to east and going up structure, are: gabbro, quartz-diorite, diabase, volcanics, the St. Daniel Formation and the Peasley Pond Conglomerate of the Glenbrooke Group. All these rocks have been metamorphosed to the greenschist facies. Contacts between the plutonic rocks are irregular and gradational indicating only one parent magma. Diabase dikes are present in the diabase unit and in the volcanics indicating the dikes acted as feeders to the volcanics. Geochemical …


The Influence Of Oceanic Transform Boundaries On The Generation And Evolution Of Oceanic Lithosphere, David G. Gallo Jan 1984

The Influence Of Oceanic Transform Boundaries On The Generation And Evolution Of Oceanic Lithosphere, David G. Gallo

Geology Theses and Dissertations

The first-order geologic and morphologic relationships at, along and proximal to ridge-transform-ridge plate boundaries are used to construct an empirical and speculative tectonic model. The geometry of a ridge-transform intersection necessitates the juxtaposition of relatively cold, thick lithosphere against the truncated end of an accreting plate boundary. The cold face of lithosphere cools the adjacent wedge of asthenosphere rising beneath the axis of accretion and restricts the amount of partial melting thus attenuating the amount of basaltic melt segregated from the asthenosphere per unit time. The manifestation of this cold edge effect is a thinner oceanic crust. At depth, upper …


Structural Analysis Of Deformed Carboniferous Strata, Mispec Beach, Southern New Brunswick, Lauren Magin Bradley Jan 1984

Structural Analysis Of Deformed Carboniferous Strata, Mispec Beach, Southern New Brunswick, Lauren Magin Bradley

Geology Theses and Dissertations

Mispec Beach, New Brunswick is a coastal exposure of deformed Carboniferous sedimentary rocks. Late Paleozoic deformation in the region is thought to have occured in a restraining bend in the Cobiquid - Chedabucto fault.
Within this exposure, two main generations of deformation are recognized. The first deformation is associated with slaty cleavage development, pebble elongation, and the formation of quartz veins. The second generation structure is a moderately developed crenulation cleavage. The diversity of structures present at this outcrop allows for a qualitative determination of the principal axes of stress and strain associated with the first generation structures.


Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M. Jan 1984

Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M.

Geology Theses and Dissertations

Detailed studies in rocks of Mettawee (Late Precambrian? to Early Cambrian) and Walloomsac (Middle Ordovician) slates between Old Chatham and East Chatham, New York, have shown that these rocks were intensely deformed during the Taconic orogeny and a later deformation event(?). Two generations of structures are clearly recognized in the area. The first generation (G1) includes tight west-verging folds whose axial plane foliation is the regional foliation slaty cleavage (S1). These structures are considered synchronous with the regional metamorphism of the Taconic orogeny and correlative with those structures belonging to the D2 deformation event proposed by Ratcliffe (1979) and Rowley …


Provenance Study Of The Middle Ordovician Sandstones Of New York And Western Vermont, Stephen A. Tanski Jan 1984

Provenance Study Of The Middle Ordovician Sandstones Of New York And Western Vermont, Stephen A. Tanski

Geology Theses and Dissertations

Medial Ordovician rocks exposed in westernmost New England and eastern New York State include thick sequences of marine sandstones which are part of a belt extending from Newfoundland to Tennessee. A petrographic study was made of 237 samples distributed across the entire outcrop belt (approx. 250 km. north-south along strike and 190 km. east-west across strike).
Two distinct types of sandstone are recognized, the oldest, and most widespread, is a deep water lithic wacke deposited by turbidity currents and found interbedded with shale (flysch). The younger sandstone is found only in the southeastern part of the study area and is …


Some Aspects Of Deformation Fabrics Along The Highland/Lowland Boundary, Northwest Adirondacks, New York State, Peter C. Hall Jan 1984

Some Aspects Of Deformation Fabrics Along The Highland/Lowland Boundary, Northwest Adirondacks, New York State, Peter C. Hall

Geology Theses and Dissertations

The Geology of the Whippoorwill Corners Area, NW Adirondacks, NYS
In the northwestern Adirondack Mountains of New York State lies a 110 km long, 0-5 km wide topographic and lithologic boundary which divides the Adirondack Highlands from the Northwest Lowlands. Structurally this boundary is apparently a highly strained zone of intensely foliated and lineated rocks. Within the zone mineral grains are highly recrystallized and of fine grain size with respect to rocks outside the zone, quartz becomes undulose, and mineral assemblages frequently exhibit retrograde characteristics. Despite the apparent high strain no demonstrable offset may be seen across the zone. Furthermore, …


1984 County Gravity Survey, Complete Gravity Listings, Raymond R. Burchett Jan 1984

1984 County Gravity Survey, Complete Gravity Listings, Raymond R. Burchett

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Annual Installation Of Irrigation Wells In Nebraska Through 1983, Conservation Survey Division Jan 1984

Annual Installation Of Irrigation Wells In Nebraska Through 1983, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Annual Departures From Average Annual Precipitation In Nebraska, 1850-1983, Conservation Survey Division Jan 1984

Annual Departures From Average Annual Precipitation In Nebraska, 1850-1983, Conservation Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Annual Departures From Average Annual Precipitation In Nebraska, 1850-1983, Conservation And Survey Division Jan 1984

Annual Departures From Average Annual Precipitation In Nebraska, 1850-1983, Conservation And Survey Division

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Inventory Of Irrigation Water Use In Box Butte County, Nebraska 1981, D. R. Lawton, L. L. Leahon Jan 1984

Inventory Of Irrigation Water Use In Box Butte County, Nebraska 1981, D. R. Lawton, L. L. Leahon

Conservation and Survey Division: Faculty and Staff Publications

No abstract provided.


Archean Metamorphism In Northwestern Ontario And Southeastern Manitoba, Kevin R. Henke Jan 1984

Archean Metamorphism In Northwestern Ontario And Southeastern Manitoba, Kevin R. Henke

Theses and Dissertations

Four areas are considered in this study. In Ontario, north-south traverses were made along Highway 599 between Savant Lake and Central Patricia, along the Vermilion River road (40 kilometers northeast of Sioux Lookout) and along Highway 105 between Vermilion Bay and Ear Falls (Fig. 3). The fourth area is centered at Bird River, northeast of Lac du Bonnet, Manitoba. The study areas are located in the Uchi, English River and Wabigoon Subprovinces.

The traverse along Highway 599 between Savant Lake and Central Patricia crosses the three subprovinces (Fig. 3). Pelites in the eastern Lake St. Joseph area (Uchi Sub province) …


Tertiary Alkalic Igneous Activity, Potassic Fenitization, Carbonatitic Magmatism, And Hydrothermal Activity In The Central And Southeastern Bear Lodge Mountains, Crook County, Wyoming, Gordon A. Jenner Jan 1984

Tertiary Alkalic Igneous Activity, Potassic Fenitization, Carbonatitic Magmatism, And Hydrothermal Activity In The Central And Southeastern Bear Lodge Mountains, Crook County, Wyoming, Gordon A. Jenner

Theses and Dissertations

The Bear Lodge Mountains are located in Crook County in north eastern Wyoming. The core of the uplift consists of alkalic igneous rocks that range from Early to Late Eocene in age. A petrologic and geochemical study of surface and subsurface samples from the southeastern and central portions of the core reveals a complex history of multiple alkalic igneous events, potassic metasomatism, carbonatitic magmatism, and hydrothermal alteration.

An early episode of alkalic igneous activity is represented by latite and trachyte porphyries, phonolite and trachyte porphyries, and natrolite-garnet syenites and malignites. Throughout much of the complex, the composition of these older …


The Effects Of Seismic Blasting On Shallow Water Wells And Aquifers In Western North Dakota, Frank W. Beaver Jr. P. E. Jan 1984

The Effects Of Seismic Blasting On Shallow Water Wells And Aquifers In Western North Dakota, Frank W. Beaver Jr. P. E.

Theses and Dissertations

Seismographic petroleum exploration throughout North Dakota has generated concern over the effects of blasting on groundwater supplies and wells. A preliminary investigation revealed complaints alleging declining productivity and decreased water quality in regions where coal aquifers are extensively used. Unplugged shotholes were frequently cited as a source of problems.

Experimental results indicate that changes due to blasting occur within long term physical the aquifers rather than in specific water wells. Pumping tests conducted in a sand and coal aquifer system showed no apparent physical effects when shots were detonated one quarter mile away from the pumping wells. Shots 500 feet …


Groundwater-Lake Interactions, Wood Lake, Benson County, North Dakota, Lori J. Ferguson Jan 1984

Groundwater-Lake Interactions, Wood Lake, Benson County, North Dakota, Lori J. Ferguson

Theses and Dissertations

Wood Lake is a kettle lake within the McHenry end moraine (late Wisconsinan) in eastern Benson County, North Dakota. It is part of the Devils Lake interior basin, near the drainage divide between the Devils Lake basin and the Big Coulee - Sheyenne River drainage. The moraine deposits, part of the Coleharbor Group, are composed of complexly interfingering lenses of gravel, sand, silt, and clay within the till.

Water levels in piezometers around Wood Lake indicate groundwater flows from the southwest into the west side of the lake and out of the lake along the east shore, toward the northeast. …


Sedimentology Of The Bullion Creek And Sentinel Butte Formations (Paleocene) In A Part Of Southern Mckenzie County, North Dakota, Brian P. Wallick Jan 1984

Sedimentology Of The Bullion Creek And Sentinel Butte Formations (Paleocene) In A Part Of Southern Mckenzie County, North Dakota, Brian P. Wallick

Theses and Dissertations

The environment of deposition of the Bullion Creek and Sentinel Butte Formations (Paleocene) in western North Dakota has been variously ascribed to lacustrine, meandering fluvial, and deltaic settings. The purpose of this study was to interpret the depositional environments, depositional history, and provenance of the strata in T. 145 and 146 N., R. 102 W., McKenzie County, North Dakota.

A total of 24 stratigraphic sections were measured and described. In addition, paleocurrent data were gathered from primary sedimentary structures, positions of paleochannel outcrops were noted, and samples were collected. Laboratory work consisted of thin-section petrography, scanning electron microscopy, and X-ray …


Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters Jan 1984

Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters

Dissertations and Theses

Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.


Implications Of Hydrocarbon And Helium Gas Analyses Of Springs From The Ouachita Mountains, Arkansas, Randel T. Cox, Kenneth F. Steele Jan 1984

Implications Of Hydrocarbon And Helium Gas Analyses Of Springs From The Ouachita Mountains, Arkansas, Randel T. Cox, Kenneth F. Steele

Journal of the Arkansas Academy of Science

One hundred and three ground water samples (predominantly springs) were analyzed for headspace light hydrocarbon gases and helium. Four of the formations (Arkansas Novaculite, Bigfork Chert, Stanley Shale, and Womble) having the highest mean methane values are the only Ouachita Mountain facies to produce petroleum or exhibit marginally commercial production. This observation suggests that the mean methane values are useful as an indication of the relative hydrocarbon content of these formations Anomalous helium values are generally associated with mapped faults.


Lithology And Sedimentology Of The Graydon Springs Channel, Pennsylvanian Of Southwestern Missouri, Gregory Lee Easson Jan 1984

Lithology And Sedimentology Of The Graydon Springs Channel, Pennsylvanian Of Southwestern Missouri, Gregory Lee Easson

Masters Theses

"The Graydon Springs Member of Southwest Missouri, here assigned to the Warner Formation of Pennsylvanian age was sampled and examined in order to document the lithology, sedimentology, source area, stratigraphic position, and overall geologic history of these channel-like bodies. The member is composed of an upper sandstone unit and a lower conglomerate unit.

Laboratory investigations of thin sections indicate that the sandstone unit is composed of well sorted, well rounded quartz and minor amounts of accessory minerals cemented with iron oxide, commonly hematite. Field observations indicate that the conglomerate unit is composed of very poorly sorted, very well rounded chert …


Relation Of Bitumen To Ore In The Magmont West Orebody, Southeast Missouri, Mark Alan Marikos Jan 1984

Relation Of Bitumen To Ore In The Magmont West Orebody, Southeast Missouri, Mark Alan Marikos

Masters Theses

"Bitumen in the form of oil blebs from the Magmont West orebody of the Viburnum Trend was examined and analysed in an attempt to relate hydrocarbon distribution and origin to ore genesis. Hydrogen, carbon, nitrogen, sulfur and oxygen percentages were determined by elemental analyses. Trace element composition was determined by emmission spectroscopy and the composition of the bitumen was calculated with respect to aromatic hydrocarbons, saturated hydrocarbons and NSO (nitrogen-sulfur-oxygen) components. The bitumen and kerogen from associated shale samples were evaluated by Rock-Eval pyrolysis and pyrolysis-gas chromatography.

The bitumen was calculated to be approximately 40 to 50 percent aromatic and …