Physical Sciences and Mathematics Commons^™

Natural Fracture Evolution: Investigations Into The Middle Devonian Marcellus Shale, Appalachian Basin, Usa, Natalie Abigail Mitchell

Graduate Theses, Dissertations, and Problem Reports

Optimizing recovery from unconventional shale reservoirs has generated considerable research into optimal recovery methods through hydraulic fracturing design and shale reservoir characterization in the development of long-term hydrocarbon producers. Permeability at multiple scales from nanometer-scale pore sizes and nano-darcy permeability to completion-induced fractures defining a 100’s of meter stimulated reservoir volume plays a significant role in hydrocarbon flow during production in shale reservoirs. Preexisting cemented fractures in unconventional shale reservoirs are abundant and preferentially reactivate during induced hydraulic fracturing treatment to create necessary large-scale permeability. While previous investigations have significantly improved our knowledge of shale reservoirs, it has also highlighted …

Precambrian Molar-Tooth Structure: Unraveling The Diagenesis Of Ancient Carbonates, Agustin Kriscautzky

Doctoral Dissertations

Molar-tooth structure (MTS) is an enigmatic carbonate fabric that occurs mainly within Proterozoic carbonate host rocks. It is composed of two distinct features: cracks of various morphologies and crack-filling calcite microspar. Although the origins of MTS remain unknown, most previous investigation has focused on the formation of the cracks and mechanisms involved in the void space generation, with less emphasis on the intriguing carbonate fill. In this study I have investigated molar-tooth bearing carbonates from regions that span both paleogeography and geologic time. Analysis at the microscopic scale, including traditional petrography, cathodoluminescence petrography, scanning electron microscopy, and micrometer-scale geochemical analyses …

Machine Learning Applied To A Modern-Pleistocene Petrographic Dataset: The Global Prediction Of Sand Mineralogy (Gloprsm) Model, Isaac Johnson

Graduate Theses and Dissertations

Petrography has long been used as a tool to decipher the sedimentary provenance of sand and sandstone from the relative proportions of framework grain types. Petrographers have also related the proportions of quartz (Q), feldspar (F), and lithic (L) grains to the processes that form and modify sediments within sediment routing systems. This past work has shown that factors including source lithology, climate, transport history, and tectonism work in concert to modify the framework mineralogy of sand. However, there is a lack of a quantitative understanding of the interactions and feedbacks between these factors and how they modify sand mineralogy. …

Geologic Characterization Of The Nonconformity Interface Using Outcrop And Drillcore Analogs: Implications For Injection-Induced Seismicity, Kayla Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Starting around 2009, a greater number of earthquakes than anticipated have occurred in the midcontinent region of the United States. These earthquakes have been linked to increased rates and volumes of wastewater injection at several km’s depth into the Earth’s crust near a contact between crystalline metamorphic or igneous rock and overlying sedimentary rock, known as a nonconformity. While much is known about why these new earthquakes occur, comparatively little is known about the physical and chemical rock properties because the nonconformity contact is primarily buried under km’s of sedimentary rock in the midcontinent region. These rock properties are important …

Hydrothermal Alteration Footprint Of The Monument Bay Project, Manitoba, Canada, Juliana Casali

Electronic Thesis and Dissertation Repository

The Monument Bay (MB) project is a greenstone hosted gold deposit, located in NE Manitoba. Previous studies show significant gold grades in the area. This research aims to characterize and delineate the mineralogical and geochemical characteristics of the hydrothermal footprint and mineralization of MB. Combined synchrotron X-ray fluorescence, synchrotron X-ray diffraction, petrography, and electron microprobe techniques were used to support this study. Results indicate sericite and carbonate are the main hydrothermal alteration minerals with homogeneity in their mineralogical, textural, and geochemical characteristics across the deposit. Also, a strong relationship between Au, sericite alteration, and arsenopyrite grains is observed associating the …

Framework Grain Composition And Texture Of The Wedington Sandstone Member, Fayetteville Shale, As A Provenance And Sediment Dispersal Indicator For Clastic Depositional Systems Across The Northern Arkansas Structural Platform During The Late Mississippian, Tanner Wayne Corbin

Graduate Theses and Dissertations

The Wedington Sandstone Member of the Fayetteville Shale is a constructive delta complex in the Chesterian section of the Late Mississippian record in Northwest Arkansas. A comparative analysis of framework grain composition between the Wedington and two other stratigraphically proximal Carboniferous sandstones: the Batesville Sandstone (older) and the Basal Atoka-Spiro Sandstone (younger) has addressed three questions: 1) Is there similarity in sediment provenance for the three sandstones? 2) Do these three sandstone units have a similar sediment dispersal vector? 3) What are likely sediment source terrains for the Wedington Sandstone? Wedington samples overwhelmingly plot as quartzarenites with fewer samples plotting …

Hardbottom Characterization And Relationship To The Geologic Framework In Long Bay, South Carolina, Cathryn J. Wheaton

Electronic Theses and Dissertations

Hardbottom seafloor is a common element among sediment-starved portions of the inner continental shelf along the U.S. Atlantic margin. These areas are characterized by indurated sediment surfaces that are heavily altered by biological and physical processes. Long Bay, in northeastern South Carolina, offers ideal environmental conditions for hardbottom exposure with only patchy Holocene sand deposits, interspersed with extensive hardbottom areas. Here we use high-resolution multibeam bathymetry, CHIRP subbottom profiling and electrical resistivity data, along with surficial sediment samples, hardbottom thin sections, and water column radioisotope (radon-222) analysis to investigate the origin and geologic framework of a region of hardbottom seafloor …

Emplacement Of The Foy, Hess And Pele Offset Dykes At The Sudbury Impact Structure, Canada, Eric A. Pilles

Electronic Thesis and Dissertation Repository

The 1.85 Ga Sudbury impact structure is the remnant of what is generally considered to have been an ~150–200 km diameter impact basin in central Ontario, Canada. The so-called Offset Dykes are impact melt dykes that are found concentrically around – and extending radially outward from – the Sudbury Igneous Complex (SIC), a ~3 km thick differentiated impact melt sheet. The dykes are typically composed of two main phases of granodiorite: an inclusion- and sulfide-rich granodiorite in the centre of the dyke, and an inclusion- and sulfide-poor granodiorite along the margins of the dyke. This study uses a combination of …

Avon Alkaline Igneous Province, Missouri: Characterization Of Subcontinental Mantle Source And Evolution Via Chemical Analysis Of Olivine, Zachary William Freeman

Masters Theses

"This article presents the crystallization age of, and composition of olivine phenocrysts within an alnoite of, the Avon Alkaline Igneous Province (AAIP) of Ste. Genevieve County, Missouri. The AAIP is an ultramafic igneous province consisting of approx. 80 known intrusives of diverse lithology and texture. ⁴⁰Ar/³⁹ Ar geochronology indicates an emplacement age of 386 +/- 1 Ma, which establishes the AAIP as the only known Devonian-age ultramafic igneous body in the Midwestern U.S. Study of the AAIP provides a unique opportunity to characterize the Devonian-age subcontinental mantle and the processes that generated the suite of ultramafic rocks present …

A Petrographic Characterization Of The Leatherwood Coal Bed In Eastern Kentucky, Michelle N. Johnston

Theses and Dissertations--Earth and Environmental Sciences

The Eastern Kentucky Coal Field is located in the central portion of the Appalachian Basin. The Pennsylvanian Breathitt Formation in this region is characterized by numerous sequences of bituminous coal-bearing sedimentary rocks. These coals have distinct maceral compositions due to variations in depositional environments. Coal characterization is an important method for determining conditions that influenced peat accumulation and overall depositional settings of mires.

This study focuses on the characterization of the maceral composition of the Middle Pennsylvanian-age Leatherwood coal bed. It utilizes petrographical, palynological, and geochemical analyses to describe specific depositional environments and associated peat accumulation conditions.

Petrographic analyses indicate …

Metamorphic Phase Equilibria In A Contact Aureole: Tres Hermanas Mountains, Luna County, New Mexico., Carissa Dawn Snyder

Masters Theses

To characterize the metamorphism in the Tres Hermanas Mountains contact–metamorphic aureole in Luna County, New Mexico, I mapped and collected samples of the Paleozoic strata near the quartz monzonite pluton along the northeast flank of North Peak. Stratigraphy in this area includes the Pennsylvanian undivided unit that is composed of thin-medium interbedded limestone, shale, and sandstone and the Hueco Formation that could be broken out into four members: a pebble–cobble conglomerate marks the base, a medium to massive bedded siliceous limestone is next, followed by a pure limestone member and topped by a breccia bed in places marking the fault …

Petrographic Signature For The Whidbey Formation, Jonathan Peterson

WWU Graduate School Collection

The late Pleistocene Whidbey Formation occupies a region on and around Whidbey Island, Washington, that received both northern-derived glacial sediments and eastern-derived nonglacial sediments. Distinguishing between glacial outwash and nonglacial sediments of the Whidbey Formation and the younger Olympia beds has been problematic where stratigraphic sections are incomplete. For the Whidbey Formation, discontinuous deposits of sand, clay, peat and silt that stem from meandering streams on floodplains have not been fully characterized, petrographically. Recent documentation (Dragovich and others, 2005) of dacitic channel and lahar-runout facies on northern Whidbey Island spurred petrographic analysis of various sands from across the whole region …

Slickenside Petrography: Slip-Sense Indicators And Classification, Young-Joon Lee

Geology Theses and Dissertations

Petrographic study has been carried out on slickenside thin sections, to find out reliable microstructures for determining the slip-sense of faults, and to classify slickensides morphologically. Thin sections are made cut parallel to the striation and perpendicular to the slip plane. Many useful slip-sense indicators are found in thin section even though such indicators may be absent in hand specimens. They are (1) off-set or bending of once-continuous bodies such as veins, layers, grains or twin lamellae, (2) crystal fibers growing nearly parallel to the slip direction, (3) extensional fractures aligned oblique to the slip plane, (4) S-C geometries in …

The Depositional Environment, Petrography, And Tectonic Implications Of Informally Named Middle To Late Eocene Marine Strata, Western Olympic Peninsula, Washington, Benjamin Nickolas Adams

WWU Graduate School Collection

The informally named marine strata examined in this study comprise fault bounded slivers of middle to late Eocene (Ulatizian to Narizian) siltstone, sandstone, and conglomerate exposed on the northwestern Olympic Peninsula. The strata are divided into three lithofacies: the sandstone of Bahobohosh, the siltstone of Waatch Point and the siltstone and sandstone of Bear Creek by Snavley et al. (1986). Six facies have been identified consisting of strata deposited by high- and low-density turbidites, storm waves, slumping, tidal or littoral currents, and debris flows. Relationships among the facies indicate shallow marine deposition that shoaled from below to above storm wave-base …

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 …

The Sedimentary Petrography, Depositional Environment And Tectonic Setting Of The Aldwell Formation, Northern Olympic Peninsula, Washington, Keith Marcott

WWU Graduate School Collection

The upper Eocene Aldwell Formation crops out in an east-west trending band across the northern Olympic Peninsula, Washington. Petrographic analyses indicate that the Aldwell Formation has lithologically distinctive eastern and western portions. The rocks of the eastern Aldwell are basalt-rich lithic greywackes; their mean compositions are Qm-F-Lt: 5- 22-73 and polycrystalline quartz-volcanic rock fragments-total sedimentary rock fragments: 1-78-21. The rocks of the western Aldwell are chert-rich lithic arenites; their mean compositions are Qm-F-Lt: 27-19-54 and polycrystalline quartz-volcanic rock fragments-total sedimentary rock fragments: 66-11-23.

Similarities in texture, composition, and alteration products suggest that the basalts of the Crescent seamount province as …

Structure And Petrography Of The Tertiary Volcanic Rocks Between Death Creek And Dairy Valley Creek (Box Elder Co.), Utah, E. Matthew Hare

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several volcanic flows lie between Death Creek and Dairy Valley Creek, near Etna, Utah. The major, central portion of the volcanic flows is composed of dacite and dacite vitrophyre. An elongate ridge in the southeastern corner of the study area and several small outcrops in Death Creek Valley are composed of rhyolite and rhyolite vitrophyre. Additional rock types include conglomerate, volcanic ash, and tuffaceous sedimentary rock of the Tertiary Salt Lake Formation, Paleozoic limestone, and Tertiary basalt.

Dacite and dacite vitrophyre samples are porphyritic, containing phenocrysts of plagioclase, quartz, biotite, amphibole, orthopyroxene, and iron-titanium oxides. Rhyolite and rhyolite vitrophyre samples …

Petrography, Mineral Chemistry And Microstructures Of Gabbros From The Mid-Cayman Rise Spreading Center, Frieda L. Malcolm

Geology Theses and Dissertations

The suite of gabbroic rocks collected by the DSRV ALVIN in 1976 and 1977 from the walls of the Mid-Cayman Rise spreading center were studied in detail to provide the best available data on plutonic rocks sampled directly from the ocean floor. The rock types studied include variably deformed and altered gabbros, orthopyroxene gabbros, olivine gabbros and troctolites, and a few amphibolites. Mineral chemical analyses suggest that the various rock types are representative of a fractionation trend from magnesian troctolites through olivine and clinopyroxene gabbros to iron-enriched orthopyroxene gabbros. Within many individual samples, the primary mineral phases are apparently chemically …

Petrology Of The Tijeras Greenstone, Bernallio County, New Mexico, John J. Bruns

Earth and Planetary Sciences ETDs

The Precambrian metamorphosis rocks of the Tijeras Canyon area crop out along a five-mile, northeast-trending belt, which lies approximately five miles east of the Sandia Mountains front, in north-central New Mexico. The sequence, to the east, is overlain uncomfortably by Pennsylvanian Madera limestone, while the trace of the Tijeras fault marks the western side.

Geology Of The Southern Part Of The Ortiz Mountains Santa Fe County, New Mexico, John W. Peterson

Earth and Planetary Sciences ETDs

The Ortiz Mountains lie in a belt of early Tertiary intrusive centers adjacent to the Rio Grande depression of north-central New Mexico. Tertiary organic activity and subsequent erosion have etched this mountain group into considerable relief.

Intrusive activity occurred during early Tertiary Espinaso time and resulted in emplacement of sills and dikes of a central stock. Correlation of volcanism with intrusive phases is difficult. Most volcansim probably occurred during the later part of Ortiz igneous activity. An elongate vent is exposed in the eastern part of the mountains and structurally occupies the highest position in the group.

The principle igneous …

The Chromite Deposits Of Stillwater And Sweetgrass Counties, Montana, Uuno Sahinen

Bachelors Theses and Reports, 1928 - 1970

In writing this report, two objects were kept in mind, (1) to explain, if possible, the origin of the chromite deposits found in Sweetgrass and Stillwater Counties, and (2) to bring up to date all information on these deposits which had thus far been available.

The work done consisted of study of the rocks and ores of the area under the microscope, both as thin sections and as polished sections, practically all of which was done at the Montana State School of Mines, during the school year of 1928 - 1929.

The rock specimens and much information as to their …