Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

Theses and Dissertations

Discipline
Institution
Keyword
Publication Year

Articles 601 - 630 of 830

Full-Text Articles in Earth Sciences

Diagenesis And Porosity Development Of The Mission Canyon And Charles Formations (Mississippian), Treetop And Whiskey Joe Fields, North Dakota, Rebecca L. Durall Jan 1987

Diagenesis And Porosity Development Of The Mission Canyon And Charles Formations (Mississippian), Treetop And Whiskey Joe Fields, North Dakota, Rebecca L. Durall

Theses and Dissertations

Rocks of the upper Mission Canyon and lower Charles Formations (Mississippian) in central Billings County, North Dakota consist of interbedded limestones, dolostones, and anhydrites which were deposited in a shallow epeiric sea. This study was limited to the upper Mission Canyon and lower Charles Formations of Treetop and Whiskey Joe fields, located along the Billings anticline in central Billings County, North Dakota. Close examination of ap~roximately 260 metres (850 feet) of upper Mission Canyon and lower Charles Formations core in the study area resulted in the separation of rocks into six lithotypes: 1) echinoderm wackestone, 2) dolomudstone, 3) neomorphic wackestone, …


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 …


Depositional Environments And Diagenesis, Winnipegosis Formation (Middle Devonian), Williston Basin, North Dakota, Nancy A. Perrin Jan 1987

Depositional Environments And Diagenesis, Winnipegosis Formation (Middle Devonian), Williston Basin, North Dakota, Nancy A. Perrin

Theses and Dissertations

In the Williston Basin, the Winnipegosis Formation is the major carbonate unit of the initial transgressive-regressive pulse of the Kaskaskia sequence. Twenty-two lithofacies were identified by well-log, core, and thin-section studies of Winnipegosis rocks; these belong to seven environments of deposition which include deep basin, deep shelf, shallow shelf, reef, lagoon, tidal flat, and evaporite basin. The deposition of the Winnipegosis and Prairie Formations were inter-related and occurred during six episodes. Following a brief hiatus separating the underlying Ashern Formation from the Winnipegosis, a clear, quiet, shallow-marine environment became established in the North Dakota portion of the Elk Point Basin. …


A Mineralogical Study Of The Harmon Lignite Bed, Bullion Creek Formation (Paleocene), Bowman County, North Dakota, Christopher J. Zygarlicke Jan 1987

A Mineralogical Study Of The Harmon Lignite Bed, Bullion Creek Formation (Paleocene), Bowman County, North Dakota, Christopher J. Zygarlicke

Theses and Dissertations

Study of the Harmon lignite bed at the Gascoyne Mine in Bowman County, North Dakota showed that most of the minerals in the coal lithobodies were detrital in origin and that variable ash deposition during combustion may be caused by variations in types and quantities of mineral phases.

The Harmon bed is part of the Bullion Creek Formation (Paleocene). Objectives of this study included: to develop scanning electron microscope/microprobe techniques for the study of minerals in coal; to determine the origins of the mineral phases; to postulate a depositional environment for the Harmon lignite; and to ascertain whether variable ash …


Evaluation Of The Interaction Between Seepage From A Municipal Waste Stabilization Lagoon, Mcville, North Dakota, And A Shallow Unconfined Aquifer, Paul R. Bulger Jan 1987

Evaluation Of The Interaction Between Seepage From A Municipal Waste Stabilization Lagoon, Mcville, North Dakota, And A Shallow Unconfined Aquifer, Paul R. Bulger

Theses and Dissertations

The McVille, North Dakota, Municipal Waste Stabilization Lagoon is situated above the McVille Aquifer, an unconfined glaciofluvial aquifer capable of significant water yields. The site contains a 3-D network of 29 monitoring wells. Standing waste-water is maintained in the clay-lined, primary-operating cell. Operating practices at the site entail periodic discharges of waste-water from the lined cell to an unlined cell, a procedure which results in rapid infiltration.

The shape and extent of the groundwater contaminant plume caused by the waste-stabilization process is best delineated by the distribution of chloride. Background wells contain less than 10 mg/L chloride. The area up …


Depositional Environments Of A Portion Of The Bullion Creek Formation (Paleocene), Western Billings County, North Dakota, Rodney K. Perkins Jan 1987

Depositional Environments Of A Portion Of The Bullion Creek Formation (Paleocene), Western Billings County, North Dakota, Rodney K. Perkins

Theses and Dissertations

The Bullion Creek Formation (Paleocene) in North Dakota is part of an Upper Cretaceous to Eocene wedge of siliciclastic rocks formed during uplift associated with the Laramide Orogeny. The Bullion Creek Formation consists predominantly of mudrocks , with fine-grained sandstone, lignite, and rare limestone lenses . Previous workers have postulated combinations of fluvial and lacustrine depositional environments for the rocks.

The study area covers 15 square kilometres in the badlands of the Little Missouri River in western Billings County, North Dakota, where approximately the upper 75 metres of the Bullion Creek Formation ls exposed. Twenty nine stratigraphic sections were measured …


Geohydrologic Evaluation Of A Proposed Coal-Ash Disposal Site Near Mandan, North Dakota, David M. Ronnei Jan 1987

Geohydrologic Evaluation Of A Proposed Coal-Ash Disposal Site Near Mandan, North Dakota, David M. Ronnei

Theses and Dissertations

Montana-Dakota Utilities Company (MDU) operates Heskett Station, a 100 megawatt coal-fired power plant, located near Mandan, North Dakota. In the process of generating electricity, MDU's Heskett Station produces approximately 62,000 tons of coal-ash annually. The ash has been disposed of by above-ground stockpiling on the plant site for the past 35 years. Limited storage space and new solid waste regulatory restrictions have necessitated the search for a new ash disposal site.

This investigation focused on selecting a disposal site that would be suitable for long-term disposal of coal-ash generated at Heskett Station. Specifically, the objective was to locate a site …


Contaminant Migration Of Oil-And-Gas Drilling Fluids Within The Glaciated Sediments Of North-Central North Dakota, William A. Beal Jan 1986

Contaminant Migration Of Oil-And-Gas Drilling Fluids Within The Glaciated Sediments Of North-Central North Dakota, William A. Beal

Theses and Dissertations

A common practice during oil and gas well-site reclamation in North Dakota is to bury the drilling muds in shallow trenches near the borehole. These muds are saltwater based (between 100,000 and 300,000 mg/L of NaCl) and can contain high concentrations of chromium, lead, and other. toxic trace metals.

Two reclaimed oil and gas well sites were chosen for study in north-central North Dakota: the Winderl site in southeastern Renville County, and the Fossum site in west-central Bottineau County. The Winderl oil well was drilled in 1959, and the drilling fluids were disposed of in a shallow pit excavated in …


Origin And Stratigraphy Of Holocene Sediments, Souris And Des Lacs Glacial-Lake Spillways, North-Central North Dakota, William M. Boettger Jan 1986

Origin And Stratigraphy Of Holocene Sediments, Souris And Des Lacs Glacial-Lake Spillways, North-Central North Dakota, William M. Boettger

Theses and Dissertations

In the past few years, a new interpretation of the formation of the Souris and Des Lacs glacial-lake spillways has been proposed. Now, based on geomorphological evidence, it is concluded that the Souris and Des Lacs Valleys were formed by massive glacial-lake outburst floods at the end of the late Wisconsinan deglaciation. Five phases of drainage have been recognized with the first forming the Des Lacs Valley and the other four associated with drainage in the Souris Valley from different proglacial lakes in Canada. The last of these floods down the Souris Valley was the most erosive.

This study is …


Conodont Biostratigraphy Of The Bakken And Lower Lodgepole Formations (Devonian And Mississippian), Williston Basin, North Dakota, Timothy P. Huber Jan 1986

Conodont Biostratigraphy Of The Bakken And Lower Lodgepole Formations (Devonian And Mississippian), Williston Basin, North Dakota, Timothy P. Huber

Theses and Dissertations

Fourteen cores were sampled and processed, and conodonts obtained were used in the biozonation of the Bakken and basal Lodgepole Formations in the Williston Basin in North Dakota. The Bakken Formation of Devonian and Mississippian age and the Lodgepole Formation, entirely of Mississippian age, are subsurface units in North Dakota. The Bakken Formation (44 metres thick) consists of, in ascending order: a lower, dark, organic shale; a middle calcareous siltstone that is divisible into three lithic units; and an upper, dark, indurated, organic shale. The Lodgepole Formation (160 to 260 metres thick) is an argillaceous, fossiliferous limestone near the Basin …


Paleontology And Stratigraphy Of The Niobrara Formation (Upper Cretaceous) Of Eastern North Dakota With Emphasis On The Calcareous Nannoplankton, Jeremy Reiskind Jan 1986

Paleontology And Stratigraphy Of The Niobrara Formation (Upper Cretaceous) Of Eastern North Dakota With Emphasis On The Calcareous Nannoplankton, Jeremy Reiskind

Theses and Dissertations

The Upper Cretaceous Niobrara Formation in eastern North Dakota consists of calcareous shales, chalks, and shaly chalks. The formation was studied from surface exposures, cores, and well logs. The Niobrara is 62 feet (19m) to 272 feet (83 m) and is thickest to the northeast, in a central linear area, and to the southwest. In a northern area, it was divided into a lower, calcareous shale member, and an upper, chalky member. In a.southern area, five stratigraphic units were recognized, in ascending order: a lower shaly chalk, a shale, a middle shaly chalk, a chalk, and an upper shaly chalk. …


Depositional History And Diagenesis Of The Upper Mission Canyon And Lower Charles Formations (Mississippian), Billings County, North Dakota, Randall A. Stephens Jan 1986

Depositional History And Diagenesis Of The Upper Mission Canyon And Lower Charles Formations (Mississippian), Billings County, North Dakota, Randall A. Stephens

Theses and Dissertations

The upper Mission Canyon and lower Charles Formations of the Madison Group (Mississippian) in central Billings County, North Dakota respectively consist of interbedded limestones and dolostones, and anhydrite. Study of these rocks was limited to Big Stick and T.R. Fields, located on the Billings Anticline, central Williston Basin.

Detailed examinations of cores from a 166 ft (51 m) section within the upper Mission Canyon and lower Charles Formations resulted in the identification of seven lithotypes: echinoderm wackestone-packstone, dolomudstone, dolomitic echinoderm wackestone, grainstone, skeletalpeloidal carbonate, laminated carbonate, and anhydrite. The stratigraphic distribution of lithotypes is consistent throughout the study area.

Deposition …


Geology, Hydrology And Hydrogeochemistry Of The West Brush Creek Development Area, Beulah Mine, Mercer County, North Dakota, Gary D. Winbourn Jan 1986

Geology, Hydrology And Hydrogeochemistry Of The West Brush Creek Development Area, Beulah Mine, Mercer County, North Dakota, Gary D. Winbourn

Theses and Dissertations

The West Brush Creek Development Area, a part of the Beulah Mine, occupies a rolling upland approximately 7 kilometres southwest of Beulah in west-central North Dakota. This study describes the geology, hydrology, and hydrogeochemistry of an 8 km2 area which is scheduled for strip mine development, and addresses the potential impacts of mining on the local hydrologic and hydrogeochemical regime.

Four previously recognized stratigraphic intervals in the Paleocene Sentinel Butte Formation were described and correlated. They are, from oldest to youngest, the Spaer, Beulah-Zap, Schoolhouse and Twin Buttes intervals, each named for the lignite bed which caps the interval. The …


The Effects Of Fly Ash And Flue-Gas Desulfurization Wastes On Groundwater Quality In A Reclaimed Lignite Strip Mine Disposal Site, Frank W. Beaver Jan 1986

The Effects Of Fly Ash And Flue-Gas Desulfurization Wastes On Groundwater Quality In A Reclaimed Lignite Strip Mine Disposal Site, Frank W. Beaver

Theses and Dissertations

Coal conversion wastes were generated at a lignite-coal-fired, steam-electric power station near Center, North Dakota, and were buried in unsaturated and saturated settings within the nearby stripmine, typical of settings used by the industry. The study ran for 8 years beginning in 1978. Approximately 240 piezometers were used for collecting groundwater level and groundwater chemistry data in the saturated zone. Pressure-vacuum lysimeters were installed to sample the unsaturated zone. Interstitial water was extracted from Shelby tube and auger samples at otherwise uninstrumented points.

More than 15,000 water-level recordings allowed precise definition of groundwater flow and occurrence at the study site. …


Shoreline Recession: Past, Present, And Future, Lake Sakakawea, North Dakota, Brian S. Sandberg Jan 1986

Shoreline Recession: Past, Present, And Future, Lake Sakakawea, North Dakota, Brian S. Sandberg

Theses and Dissertations

Shoreline erosion is a major problem at Lake Sakakawea, North Dakota. Instrumentation along the eastern shore was initiated in 1983 to measure shoreline recession and determine the processes responsible, with the ultimate goal being the development of a relatively simple equation to predict the rate of recession which is better than the model currently used by the U.S. Army Corps of Engineers.

For the twenty stations, the present rate of recession ranges from 0.2 to 4.3 m/y. Approximately 78 percent of the yearly recession occurs during the warm months (May-October) due to wave erosion. Erosion over the cold months occurs …


Deflation Basin Stratigraphy: Southwestern North Dakota, Robert E. Seidel Jan 1986

Deflation Basin Stratigraphy: Southwestern North Dakota, Robert E. Seidel

Theses and Dissertations

The goal of this study was the determination of a similar depositional sequence for sediments from a number of shallow basins in southwestern North Dakota and the comparison of this sequence with other work either in the area or in similar geographic environments.

Samples were obtained by augering, coring, and trenching selected basins. They were analyzed by means of: core description; detailed texture analyses on selected cores by sieve, pipette, and SediGraph techniques; and mineralogy by x-ray diffraction. Computer analyses were used to characterize grain-size distributions and to correlate texture and mineralogy by cross-association.

The results of the study verified …


Depositional History And Diagenesis Of The Sherwood And Bluell Beds (Mississippian) Southwestern Renville County, North Dakota, Christopher F. Quinn Jan 1986

Depositional History And Diagenesis Of The Sherwood And Bluell Beds (Mississippian) Southwestern Renville County, North Dakota, Christopher F. Quinn

Theses and Dissertations

The Sherwood "bed" and the overlying Bluell "bed" are two log-defined zones at the top of the Frobisher-Alida interval. The Frobisher-Alida interval, within either the Mission Canyon carbonates or the overlying Charles evaporites, is composed of a number (up to six) of log-defined zones. On the northeast flank of the Williston Basin the zones are separated by even, lithologically homogeneous argillaceous marker beds. Basinward, these marker beds terminate into less argillaceous carbonates.

The area studied covered four townships in southwest Renville·county, North Dakota. The section studied included the K-1 marker, the Sherwood bed (with the Sherwood argillaceous marker), and the …


Petrology, Mineralogy, And Geochemistry Of The Goldlund Gold Deposit, Northwestern Ontario, Steven D. Giddings Jan 1986

Petrology, Mineralogy, And Geochemistry Of The Goldlund Gold Deposit, Northwestern Ontario, Steven D. Giddings

Theses and Dissertations

The Goldlund Mine is located in the Wabigoon Sub province of the Canadian Shield. Although the mine has been open sporadically since the late 1930's, little is known about the geochemistry and petrography of the deposit. The purpose of this study was to use petro-graphic, geochemical, and physical data to document and better understand the host rock, alteration, and mineralization of the deposit, and to develop a generalized model of formation.

Results showed that the host rocks of the gold mineralization are albitized tonalite dikes. Gold, in native form and in gold-silver tellurides, occurs in quartz veins and in adjacent …


Metamorphism In The Eastern Lac Seul Region Of The English River Subprovince, Ontario, Steve J. Chipera Jan 1985

Metamorphism In The Eastern Lac Seul Region Of The English River Subprovince, Ontario, Steve J. Chipera

Theses and Dissertations

The English River subprovince of the Superior Province, Canada, is a linear, east-west trending high-grade metamorphic belt which extends from Lake Winnipeg in the west, to the James Bay lowlands in the east. It is composed of two prominent lithologic domains: a northern sedimentary gneiss-migmatite domain, and a southern plutonic domain. The northern domain consists primarily of alternating migmatized layers of garnet-biotite "wacke" and garnet-cordierite-biotite "pelitic" metasediments. The southern domain is composed mainly of intermediate granitic to trondhjemitic plutons. Bordering to the north and south are the lower grade Uchi and Wabigoon greenstone belts. Metamorphism and migmatization occurred during the …


Depositional Environments And Diagenesis Of Carbonates And Associated Evaporites, Frobisher-Alida Interval, Madison Group (Mississippian), Williston Basin, Northwestern North Dakota, Thomas J. Obelenus Jan 1985

Depositional Environments And Diagenesis Of Carbonates And Associated Evaporites, Frobisher-Alida Interval, Madison Group (Mississippian), Williston Basin, Northwestern North Dakota, Thomas J. Obelenus

Theses and Dissertations

The Frobisher-Alida interval is a subsurface, marker-defined unit, one of several units designated for rocks of the Madison Group (Mississippian) in the Williston Basin of North Dakota. The Frobisher Alida conformably overlies the Tilston interval and is conformably overlain by the Ratcliffe interval. 1t attains a maximum thickness of a little over 400 feet (123 m) and thins to an erosional edge along the eastern margin of the Basin.

The Frobisher-Alida is composed of limestones, dolomitic limestones, and dolostones of the Mission Canyon Formation and anhydrites of the overlying Charles Formation which exist in a complex facies relationship within the …


Late Quaternary Environmental And Climatic History Of The Southern Chilean Lake Region Interpreted From Coleopteran (Beetle) Assemblages, John W. Hoganson Jan 1985

Late Quaternary Environmental And Climatic History Of The Southern Chilean Lake Region Interpreted From Coleopteran (Beetle) Assemblages, John W. Hoganson

Theses and Dissertations

A diverse Coleoptera fauna of 462 species in 48 families was collected from 41 locations in the Parque Nacional de Puyehue and adjacent parts of the Lake Region of southern Chile. The sample locations ranged from rain forest habitats at sea-level to Andean tundra habitats at 1500 m msl. Cluster analysis of a Dice similarity coefficient matrix revealed a broad pattern of bioassociations within the large data base, Boundaries between the bioassociations correspond largely with those of the major vegetation zones implying that the distribution of the fauna is strongly influenced by the distribution of plants. Evidence from fossils indicates …


The Geology And Hydrocarbon Potential Of The Dawson Bay Formation Carbonate Unit (Middle Devonian), Williston Basin, North Dakota, Wayne R. Pound Jan 1985

The Geology And Hydrocarbon Potential Of The Dawson Bay Formation Carbonate Unit (Middle Devonian), Williston Basin, North Dakota, Wayne R. Pound

Theses and Dissertations

The Middle Devonian Dawson Bay Formation carbonate unit is present in the subsurface of North Dakota except where truncated by post-depositional erosion. The carbonate unit thickens from the erosional limit to a maximum thickness of 47.5 m (156 ft.) in Renville County and reaches a maximum depth of 3798 m (12, 432 ft.) below the surface in McKenzie County. In North Dakota, a submarine hardground separates the carbonate unit from the underlying “Second Red Bed member” of the Dawson Bay Formation. The upper contact with the Souris River Formation is conformable except in those areas where the Dawson Bay Formation …


Palynology Of The Hagel Lignite Bed And Associated Strata, Sentinel Butte Formation (Paleocene), In Central North Dakota, Edward N. Steadman Jan 1985

Palynology Of The Hagel Lignite Bed And Associated Strata, Sentinel Butte Formation (Paleocene), In Central North Dakota, Edward N. Steadman

Theses and Dissertations

The Hagel bed is an economically important lignite and is the lowest named lignite in the Sentinel Butte Formation, Fort Union Group. The Hagel bed extends throughout the Knife River Basin coal-mining area of central North Dakota. Stratigraphic sections of the Hagel bed, including intercalated clastic rocks, were measured in the highwalls of the Center mine, Glenharold mine, and Falkirk mine.

Samples from the stratigraphic sections were described and analyzed, using standard palynological techniques, for their palynomorph content. Palynomorphs proved to be well preserved and abundant. Maceration of Hagel bed samples yielded a diverse collection of palynomorphs. A total of …


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 Beulah-Zap Lignite Bed, Sentinel Butte Formation (Paleocene), Mercer County, North Dakota, David R. Kleesattel Jan 1985

Petrology Of The Beulah-Zap Lignite Bed, Sentinel Butte Formation (Paleocene), Mercer County, North Dakota, David R. Kleesattel

Theses and Dissertations

The Beulah-Zap lignite bed is one of several economically important lignites in the Sentinel Butte Formation (Paleocene). This lignite occurs as a subsurface unit in the Knife River Basin of Mercer and I Oliver counties of North Dakota. The Beulah-Zap lignite is a heterogeneous carbonaceous rock unit composed of megascopic and microscopic I components, which are lithotypes and macerals, respectively. Relationships between the maceral contents of the lithotypes follow patterns similar to those of bituminous coals. Coal petrology, the study of maceral and lithotype occurrence and I distribution, was applied to determine: 1) mode of coalification, and 2) depositional environment …


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 …


Macrofossils And Biostratigraphy Of The Bakken Formation (Devonian And Mississippian) In Western North Dakota, Lawrence C. Thrasher Jan 1985

Macrofossils And Biostratigraphy Of The Bakken Formation (Devonian And Mississippian) In Western North Dakota, Lawrence C. Thrasher

Theses and Dissertations

The Bakken Formation, up to 145 feet thick in North Dakota, is a subsurface formation in the Williston Basin that typically consists of two black shale members separated by a middle member of predominantly gray siltstone or silty limestone up to 85 feet thick.

Well over 500 macrofossils representing more than 50 taxa were collected from cores of 40 wells. Brachiopods, the most common fossil, represent 17 genera, 1 of which have not been previously reported from the Bakken. Nonbrachiopod fossils of this study, mostly not previously reported from the Bakken, are a hylothyrid, a conulariid, a syringoporid coral, several …


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 …