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Articles 631 - 660 of 830
Full-Text Articles in Earth Sciences
Sedimentology Of The Bullion Creek And Sentinel Butte Formations (Paleocene) In A Part Of Southern Mckenzie County, North Dakota, Brian P. Wallick
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 …
Bivalve Associations Of The Cannonball Formation (Paleocene, Danian) Of North Dakota, Rosanne M. Lindholm
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 …
Conodonts Of The Bakken Formation (Devonian And Mississippian), Williston Basin, North Dakota, Michael D. Hayes
Conodonts Of The Bakken Formation (Devonian And Mississippian), Williston Basin, North Dakota, Michael D. Hayes
Theses and Dissertations
The Bakken Formation is a thin (maximum 145 ft., 44 m), predominantly elastic unit in the subsurface of the Williston Basin in the United States and Canada. The formation consists of two, mostly non-calcareous, grayish-black to brownish-black shales separated by light to dark gray, calcareous and dolomitic siltstone and fine-grained sandstone. The carbonaceous, black shales of the Bakken produce a distinctive geophysical marker and are a major source rock for hydrocarbons in the Williston Basin.
Conodonts were selectively sampled from cores of the Bakken in North Dakota in an effort to determine the age and thermal maturity of the formation. …
The Ashern Formation (Middle Devonian) In The Williston Basin, North Dakota, Frederick K. Lobdell
The Ashern Formation (Middle Devonian) In The Williston Basin, North Dakota, Frederick K. Lobdell
Theses and Dissertations
The Ashern Formation (Middle Devonian) is the basal unit of the Kaskaskia Sequence in North Dakota. It unconformably overlies the Interlake Formation (Silurian) and underlies, probably paraconformably, the Winnipegosis Formation (Middle Devonian). The Ashern is present in the northwestern one-half of the state, and attains a maximum thickness of 180 feet (55 meters) The Ashern Formation may be subdivided into a lower red member and an upper gray member. The latter directly overlies the Interlake Formation where the red member is absent. Both members are argillaceous, microcrystalline dolostones containing minor quartz silt. Anhydrite, present in both members, is much more …
The Effects Of Seismic Blasting On Shallow Water Wells And Aquifers In Western North Dakota, Frank W. Beaver Jr. P. E.
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 …
Stratigraphy And Depositional Environments Of The Three Forks Formation (Upper Devonian), Williston Basin, North Dakota, Gayle M. Dumonceaux
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 …
Heavy Minerals Of The Cretaceous Hell Creek And Paleocene Ludlow Formations Of Slope And Bowman Counties, North Dakota, Robert A. Farris
Heavy Minerals Of The Cretaceous Hell Creek And Paleocene Ludlow Formations Of Slope And Bowman Counties, North Dakota, Robert A. Farris
Theses and Dissertations
The Cretaceous Hell Creek and Paleocene Ludlow Formations of southwestern North Dakota are nonmarine sediments of alluvial origin. The heavy minerals of these formations were specifically studied to determine the source rock types and their provenance, and generally assess the diagenetic processes which affected the heavy minerals.
The heavy minerals include zircon, rutile, tourmaline, garnet, ilmenite, spinel, apatite, epidote, sphene, pyroxene, dolomite, biotite, andalusite, pyrite, monazite, and barite. Most of the heavy minerals have angular shapes, indicating one cycle of erosion and deposition.
The heavy mineral percentages of the concretions and surrounding sediments were compared within and between the Hell …
Stratigraphy And Depositional Environments Of The Fox Hills Formation (Upper Cretaceous), Bowman County, North Dakota, Daniel J. Daly
Stratigraphy And Depositional Environments Of The Fox Hills Formation (Upper Cretaceous), Bowman County, North Dakota, Daniel J. Daly
Theses and Dissertations
The sedimentary structures, trace fossils, and lithology of the Upper Cretaceous Fox Hills Formation in Bowman County, North Dakota, were studied during the summer of 1979 and the spring of 1983. Twenty-three stratigraphic sections were measured and described and lithologic samples were collected for textural and mineralogical analysis, also, the major outcrops of the formation in the Dakotas and Montana were visited.
The formation in the study area was previously defined as a 27-mthick sandstone unit, containing three members--ascending, Trail City, Timber Lake, and Colgate--that was conformable with the underlying Pierre and overlying Hell Creek Formations. The Fox Hills, as …
Groundwater-Lake Interactions, Wood Lake, Benson County, North Dakota, Lori J. Ferguson
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. …
Archean Metamorphism In Northwestern Ontario And Southeastern Manitoba, Kevin R. Henke
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) …
Paleohydraulics Of Pleistocene Drainage Development Of The Souris, Des Lacs, And Moose Mountain Spillways, Saskatchewan And North Dakota, Mark L. Lord
Theses and Dissertations
Recent recognition of the rapid draining of numerous glacial lakes, including some in the Northern Plains, has revealed 'a need for further research concerning this process. Geomorphic interpretation of the Souris, Des Lacs, and Moose Mountain Valleys, and the gravel deposits in them, has resulted in the recognition of five phases in the development of the drainageways. Textural analyses and paleohydraulic methods were applied to the sediments associated with each phase to distinguish and characterize the discharges. Four of the five phases of development involved short-lived, high velocity (>4 m/s) discharges resulting from the rapid draining of glacial lakes; …
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 Geochemical Evolution Of Saline Groundwater Within A Fresh Water Aquifer South Of Oakes, North Dakota, David L. Williams
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
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 …
Depositional Cycles And Coral Distribution, Mission Canyon And Charles Formations, Madison Group (Mississippian), Williston Basin, North Dakota, Douglas L. Waters
Depositional Cycles And Coral Distribution, Mission Canyon And Charles Formations, Madison Group (Mississippian), Williston Basin, North Dakota, Douglas L. Waters
Theses and Dissertations
The distribution of corals, other fossils, and rock types of the Madison Group in the Williston Basin were studied in 29 cores (involving over 6,200 feet of core) from the Bottineau, Tilston, Frobisher-Alida, and Ratcliffe intervals in the western half of North Dakota. Occurrence of rock types, corals, and other fossils (brachiopods, bryozoans, red algae, and gastropods) of the Mission Canyon and lower Charles Formations were plotted in three cross-sections against the informal marker-defined intervals (Tilston, Frobisher-Alida, and Ratcliffe), as identified from well logs. Distribution and abundance of corals in nine of the more extensive cores were related to interpreted …
Stratigraphy Of The Inyan Kara Formation (Lower Cretaceous) In The Vicinity Of The Nesson Anticline, Northwestern North Dakota, Brad L. Wartman
Stratigraphy Of The Inyan Kara Formation (Lower Cretaceous) In The Vicinity Of The Nesson Anticline, Northwestern North Dakota, Brad L. Wartman
Theses and Dissertations
The Lower Cretaceous Inyan Kara Formation, at the base of the Dakota Group, consists of sandstone, siltstone, shale, and coal. The stratigraphy of the Inyan Kara and facies relationships within the formation and with the underlying Swift and overlying Skull Creek Formations in the vicinity of the Nesson Anticline, northwestern North Dakota, were evaluated using 11 cross-sections, 163 borehole geophysical logs, and 1 well core.
The Inyan Kara can be differentiated on well logs into three members. The basal member, "A", consists of sandstone, siltstone, shale, and coal. It is about 200 feet (60 m) to 400 feet (122 m) …
Depositional Environments And Diagenesis, Interlake Formation (Silurian), Williston Basin, North Dakota, Charles L. Lobue
Depositional Environments And Diagenesis, Interlake Formation (Silurian), Williston Basin, North Dakota, Charles L. Lobue
Theses and Dissertations
The Interlake Formation is a succession of Silurian carbonates of large areal extent found in the Williston Basin. The Interlake attains a maximum thickness of about 1,100 feet in western North Dakota and thins to an erosional edge in eastern North Dakota,
The main purpose of this study was to interpret the depositional and diagenetic history of the Interlake Formation. Approximately 2,400 feet of Interlake core and 300 thin sections were studied, The Interlake was then divided into twelve lithotypes representing deposition in low-energy sublittoral, high-energy sublittoral, littoral, and supralittoral epeiric sea environments. In addition, paleosols are present,
Rocks that …
The Effect Of Oil-And-Gas Well Drilling Fluids On Shallow Groundwater In Western North Dakota, Edward C. Murphy
The Effect Of Oil-And-Gas Well Drilling Fluids On Shallow Groundwater In Western North Dakota, Edward C. Murphy
Theses and Dissertations
Upon completion of an oil-and-gas well in North Dakota the drilling fluid is buried in the reserve pit at the site. Reclamation of the drill site is expedited by digging a series of trenches which radiate out from the reserve pit, The majority of buried drilling fluid is ultimately contained within these 5-7 metre deep trenches. These fluids are commonly salt-based, i.e. they contain a con centration of 300,000±20,000 ppm NaCl. In addition, these drilling fluids also contain additives including toxic trace-metal compounds.
Four reclaimed oil~and-gas well sites were chosen for study in western North Dakota. The ages of these …
A Survey Of 24 Elements In North Dakota Lignite (Fort Union Group, Paleocene) And Possible Geologic Implications, Susan A. Zimmer-Dauphinee
A Survey Of 24 Elements In North Dakota Lignite (Fort Union Group, Paleocene) And Possible Geologic Implications, Susan A. Zimmer-Dauphinee
Theses and Dissertations
Calystone, carbonaceous shale, lignitic shale, and lignite samples were collected from western North Dakota for element analysis during May 1978, April 1979, and August 1979. Lignite was collected from the Sentinel Butte Formatlon--Hagel Bed (Oliver and McClean Counties), Beulah-Zap Bed (Mercer County), Lehigh Bed (Stark County)-- and from the Bullion Creek Formation--Harmon Bed (Bowman County). Claystone samples were also collected from clay partings present in the Hagel Bed and Harmon Bed. Control samples were collected from an outcrop of the marine lower middle Cannonball Formation (carbonaceous shale) south of Mandan, North Dakota and from an outcrop of the brackish oyster …
The Effect Of Waste Stabilization Pond Seepage On Groundwater Quality Of Shallow Aquifers In Eastern North Dakota, David J. Brown
The Effect Of Waste Stabilization Pond Seepage On Groundwater Quality Of Shallow Aquifers In Eastern North Dakota, David J. Brown
Theses and Dissertations
The use of stabilization ponds to dispose of municipal wastes has become popular with many North Dakota cities. When managed properly they are an efficient and economical method of waste disposal and may not adversely affect groundwater quality. In order to achieve efficient treatment, the ponds must be built in sediment that has permeability low enough to inhibit excessive percolation of wastewater into the subsurface. Some North Dakota cities have not met this basic requirement in the construction of their ponds. As a result, insufficiently treated pond liquids are allowed to reach the water table, potentially contaminating groundwater supplies. Three …
Glacial Stratigraphy Of Northwestern Cass County, North Dakota, Sharon K. Falcone
Glacial Stratigraphy Of Northwestern Cass County, North Dakota, Sharon K. Falcone
Theses and Dissertations
Field mapping, construction of cross-sections, and laboratory analyses of field samples were used to map, describe, and correlate the Late Wisconsinan glacial sediments of northwestern Cass County, North Dakota and to interpret the glacial history of the area.
The surficial geology of the area was interpreted as: 1) collapsed glacial sediment, 2) glacial sediment draped over pre-existing glaciolacustrine topography, 3) proglacia1 lake sediment, 4) wave-eroded glacial and lake sediments and 5) recent river sediment. Landforms within each of these areas include eskers, abandoned or overfit river channels, transverse ridges, ice thrust masses, kettles and beach deposits.
Seven lithostratigraphic units were …
Quaternary Geology Of The Knife River Indian Villages National Historic Site, John Reiten
Quaternary Geology Of The Knife River Indian Villages National Historic Site, John Reiten
Theses and Dissertations
The archeology of the Knife River Indian Villages National Historic Site is being studied by the University of North Dakota Anthropology Department. The age of the near surface sediment and depositional history of Quaternary sediments are useful to archeologists involved in locating and interpreting the cultural resources of this area.
There are eight river terraces within a 300 square kilometre area surrounding the Knife River Indian Villages National Historic Site, near Stanton, North Dakota. , The terraces are former river floodplains that have been preserved above the present floodplain. The elevation above river level of the Pleistocene terraces are listed: …
Petrology And Alteration In The Core Of The Bear Lodge Tertiary Intrusive Complex, Bear Lodge Mountains, Crook County, Wyoming, Michael Wilkinson
Petrology And Alteration In The Core Of The Bear Lodge Tertiary Intrusive Complex, Bear Lodge Mountains, Crook County, Wyoming, Michael Wilkinson
Theses and Dissertations
The Bear Lodge complex is an elongate, dome-shape uplift about 8.5 km long by 4 km wide, 10 km northwest of Sundance, Wyoming. The study area is centered about Warren Peaks and includes approximately 23 km2. The igneous intrusive core of the complex is mostly alkali trachyte but latite is abundant in the southern portion of the complex. Phonolite, pseudoleucite trachyte porphyry, and carbonatite dikes cut across the core. Precambrian granitic rocks and lower Paleozoic sedi mentary rocks flank the intrusion and occur as xenoliths.
The latite is relatively unaltered and consists mostly of oligo clase, andesine, alkali feldspar, salite, …
Petrology, Geochemistry And Economic Geology Of Selected Gold Claims In Rocks Of The Wasekwan Lake Area, Lynn Lake District, Manitoba, Canada, Douglas Scott Kenaley
Petrology, Geochemistry And Economic Geology Of Selected Gold Claims In Rocks Of The Wasekwan Lake Area, Lynn Lake District, Manitoba, Canada, Douglas Scott Kenaley
Theses and Dissertations
The purpose of this investigation was to map and study, both at regional and detailed scales, the units encountered within seven gold claims that were staked by Sherritt-Gordon Mines Limited of Lynn Lake, Manitoba. The claims are located in the wasekwan Lake area, approximately 12. 8 km southeast of Lynn Lake. Regional mapping was conducted at a scale of 1:12000 over a 6.4 km2 area and detailed mapping of potentially economic areas was conducted at a scale of 1:240. Whole-rock geochemistry, microprobe, optical and X-ray diffraction procedures were employed to describe and characterize the rocks. The Aphebian rock units of …
Glacial Geology And Stratigraphy Of Southeastern Pierce And Southwestern Benson Counties, North Dakota, Arthur W. Schnacke Jr.
Glacial Geology And Stratigraphy Of Southeastern Pierce And Southwestern Benson Counties, North Dakota, Arthur W. Schnacke Jr.
Theses and Dissertations
The study area includes 220 square miles in southeastern Pierce and southwestern Benson Counties, North Dakota (T. 152 N. through T. 154 N., R. 70 W. through R. 73 W.).
,
Field mapping and subsequent analyses were attempted to differentiate the drifts of the Leeds and Souris lobes, to determine the sequence and duration of events during and subsequent to glaciation, and to aid in correlating the drifts. Landforms of the area include: ice marginal ridges, ground moraine, proglacial plains, abandoned river channels, and sand dunes.
In the laboratory, very coarse sand lithology percentages, till fabric, texture, and gross lithology …
Depositional Environments And Diagenesis Of The Ratcliffe Interval, Madison Group (Mississippian), Williston Basin, North Dakota, Diane M. Catt
Depositional Environments And Diagenesis Of The Ratcliffe Interval, Madison Group (Mississippian), Williston Basin, North Dakota, Diane M. Catt
Theses and Dissertations
The Ratcliffe interval in North Dakota is a log marker-defined unit in the Williston Basin. It is Mississippian in age and crosscuts the lower Charles and upper Mission Canyon Formations of the Madison Group. Study of cross-sections, well core, and thinsections show that the Ratcliffe is comprised of six major facies: 1) brachiopod-bryozoan-echinoderm wackestone/packstone, 2) peloid packstone/wackestone, 3) oolite-peloid packstone, 4) laminated mudstone, 5) quartz siltstone packstone, and 6) anhydrite-dolomite mudstone. These facies were deposited in a regressive setting.
The initial deposition consisted mainly of marine limestones. The environment gradually became more restricted and deposition of large amounts of anhydrite …
Carbonate Bodies Within The Basal Swift Formation (Jurassic) Of Northwestern North Dakota, Tina M. Langtry
Carbonate Bodies Within The Basal Swift Formation (Jurassic) Of Northwestern North Dakota, Tina M. Langtry
Theses and Dissertations
The carbonate bodies of the basal Swift Formation (Upper Jurassic) occur as anomalous deflections on a relatively uniform mechanical well log section. The areal distribution, stratigraphic relationships, and genesis of the carbonate bodies were determined by using the gamma ray log, the spontaneous-potential log, the resistivity log suite, and megascopic and microscopic core analysis.
The carbonate bodies of the basal Swift Formation are coarsening upward sequences composed of predominantly sand-sized, recrystallized mollusk grains. These grains were transported by strong bottom cur rents across the irregular sea floor of the shallow epicontinental Jurassic sea, and were deposited under agitated water conditions …
Depositional Environment And Diagenesis, Birdbear Formation (Upper Devonian) Williston Basin, North Dakota, Peter T. Loeffler
Depositional Environment And Diagenesis, Birdbear Formation (Upper Devonian) Williston Basin, North Dakota, Peter T. Loeffler
Theses and Dissertations
The Birdbear Formation is a subsurface unit that is present throughout North Dakota except where truncated by post-depositional erosion. An angular unconformity is present between the Birdbear and younger strata in areas where the Three Forks Formation does not overlie the Birdbear. An isopach map of the Birdbear, constructed from drill-hole log data, indicates that the formation generally thickens gradually from the erosional limit to a maximum of 119 feet north of the center of the Basin. A structure map o~ the top of the Birdbear shows a basin that reaches 9000 feet below sea level.
The Birdbear is predominantly …
Depositional Environments And Sandstone Diagenesis In The Tyler Formation (Pennsylvanian), Southwestern North Dakota, Stephen D. Sturm
Depositional Environments And Sandstone Diagenesis In The Tyler Formation (Pennsylvanian), Southwestern North Dakota, Stephen D. Sturm
Theses and Dissertations
The Tyler Formation, of Early Pennsylvanian age, in southwestern North Dakota may be divided into upper and lower units, reflecting both a change in lithology and depositional environments. The lower unit is dominated by varicolored, noncalcareous shales and mudstones, siltstones, thin coal beds, and medium-grained sandstones. The upper unit in the areas of the Square Butte to Fryburg fields may be divided into a lower subunit, dominated by dark gray to grayish-black, argillaceous limestones and calcareous shales, and an upper subunit dominated by grayish-red, anhydritic limestones, varicolored to reddish-brown, calcareous shales, and locally, thin anhydrite. In the area of the …
Analysis Of Petroleum Source Rocks Of The Bakken Formation (Devonian And Mississippian) In North Dakota, Rick L. Webster
Analysis Of Petroleum Source Rocks Of The Bakken Formation (Devonian And Mississippian) In North Dakota, Rick L. Webster
Theses and Dissertations
The Bakken Formation of North Dakota consists of upper and lower, black, organic-rich shales separated by a calcareous siltstone middle member. The formation is a relatively thin unit (maximum thickness of 145 feet) with the lower shale .attaining a maximum thickness of 50 feet and the upper shale a maximum thickness of 23 feet. The shales are hard, siliceous, pyritic, fissile, and noncalcareous. They contain abundant conodonts and tasmanites and have planar laminations accented by pyrite. The upper and lower shales were apparently deposited in an offshore, marine, anoxic environment where anoxic conditions may have been caused by silling of …