The thermal and diagenetic evolution of Carboniferous sandstones in the central Appalachian basin has been resolved using various techniques. Paleothermometers including vitrinite reflectance and fluid inclusions indicate that burial of Lower and Upper Pennsylvanian strata of the Appalachian Plateau in West Virginia exceeded 4.4 km during the late Permian and occurred at a rate of ~100 m/m.y. Exhumation rates of ~10-30 m/m.y. from maximum burial to present depth were constrained using published apatite fission track and radiogenic helium ages. Quartz, lithic and feldspar-rich sandstones from different stratigraphic intervals and locations were sampled from core (95 %) and outcrop (5%) to qualitatively and quantitatively evaluate sandstone diagenesis. A compositional multivariate data set compiled from point counts served as the basis for quantitative analysis of controls on sandstone diagenesis such as framework grain composition, paleoclimate and depositional environment. A priori groups (independent variables) corresponding to the controls were compared using digenetic products (dependent variables). Major conclusions of the analysis are, first, minerals that formed early appear to have been influenced by stratigraphic position. The distribution of siderite and iron-oxide/oxyhydroxide may reflect the second order paleoclimatic signature recognized throughout the Carboniferous, where siderite formed during everwet periods and iron-oxide/oxyhydroxide during semi-arid conditions, reflecting differences in redox. Second, framework grain composition controlled the distribution of diagenetic alterations and quartz cementation in the burial environment. Lithic arenites are deficient in authigenic quartz, yet have undergone various degrees of illitization. The quartz deficiency is attributed to compaction-related loss of primary porosity relatively early, which inhibited flow of silica-bearing fluids. Finally, no correlation can be demonstrated between depositional environment and diagenesis. Anomalously high fluid inclusion homogenization temperatures (> 215 °C) from Upper Pennsylvanian sandstones adjacent to the Alleghany Thrust Front indicate that tectonic setting played an important role in quartz authigenesis. The discrepancy between the fluid inclusion and vitrinite reflectance data imply that warm silica-bearing fluids, likely sourced from low-grade metamorphic reactions, were injected into Pennsylvanian sandstone aquifers during thrust loading associated with the Alleghanian orogeny. / Ph. D.

Microbes, including fungi and bacteria, and insects are responsible for the consumption and subsequent degradation of plant materials into humus. These microbes directly and indirectly affect the physical and chemical characteristics of coal macerals. Efforts to understand and determine the origins of inertinite macerals are largely misrepresented in the literature, conforming to a single origin of fire. This study focuses on the variability of physical and inferred chemical differences observed petrographically between the different inertinite macerals and discusses the multiple pathways plant material may take to form and or degrade these macerals. Petrographic results show that fungal activity plays a fundamental role in the formation of inertinite macerals, specifically macrinite and non-fire derived semifusinite. Fungal activity chemically removes the structural framework of woody plant tissues, forming less structured to unstructured macerals. Insect activity within a mire also greatly influences the inertinite maceral composition. Wood-consuming insects directly degrade wood tissue leading to the formation of less structured inertinites, as well as producing large conglomerates of inert fecal pellets chemically similar to the original plant tissue that may be represented in the inertinite maceral composition.

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 that these coals have relatively high liptinite and varying inertinite content, along with trace amounts of mineral matter. Vitrinite, mainly in the form of collotelinite, is the most dominant maceral group. Geochemical data reveal low ash and sulfur content. Ancillary palynological data shows the palynomorph assemblage to be dominated by tree fern and large lycopsid tree spores, with lesser amounts of small lycopsid tree, small fern, and cordaites and calamites spores. The petrographic, geochemical and palynological data indicate that both domed, ombrotrophic, and planar, rheotrophic mire conditions, with limited local detrital influx, contributed to the formation of the Leatherwood coal.

The Upper Mississippian (Chesterian) Bluefield Formation of southeastern West Virginia and southwestern Virginia is the basal unit of the Mauch Chunk Group, a succession of predominantly siliciclastic strata sourced from actively rising tectonic highlands east of the Appalachian Basin. The Bluefield Formation conformably overlies shallow-marine carbonate units of the Greenbrier Group, and is unconformably overlain by incised fluvio-estuarine facies of the Stony Gap sandstone member (Hinton Formation). Outcrops along the Allegheny Front were investigated sedimentologically and structurally, and subjected to gamma ray analysis. Composite outcrop sections from deformed rocks of the Allegheny Front were correlated with the relatively undeformed rocks in the subsurface of the Appalachian Basin to the west using over 100 commercial oil and gas test wells. Regional subsurface cross-sections and isopachs define a depocenter in the southeastern part of the study area. Measured outcrop sections reveal that the stratigraphic record in the depocenter consists predominantly of meter-scale, upward-shallowing parasequences, each capped by a flooding surface. These parasequences are stacked into four regionally correlatable depositional sequences. On the basin margin to the southwest and northwest, incised valleys, and fewer meter-scale parasequences characterize depositional sequences. Stacking of parasequences into sequences reflects a hierarchy of greenhouse-type 5th order, and icehouse-type 4th order eustatic changes superimposed on differential subsidence. Due to early Alleghenian thrust loading, the depocenter experienced greater total accommodation, which prevented incision during lowstands. Instead, in the depocenter, lowstands are typified by preservation of 5th order coal-bearing parasequences. Basin-margin areas experienced less total accommodation resulting in development of 4th order lowstand incised valleys and erosive removal of parasequences. This study demonstrates that both tectonic and eustatic forcing mechanisms controlled stratigraphic evolution of the Bluefield Formation. / Master of Science

Factors controlling cyclic sedimentation are discussed in a parallel study of two evaporite-bearing sequence, the Zechstein of Germany and the Silurian Salina Group of the Appalachian Basin. The Zechstein sequence was deposited in a basin that had received the debris swept in from the Variscan orogenic zone. The deposition of the evaporite-bearing sequence took place during a period of tectonic calm, preceded and succeeded by mild late Variscan movements. The sequence is divided into four major cycles by shale horizons accompanied and basinwards partially replaced by dolomites and anhydrites. Halite is the dominant sediment, it contains beds of anhydrite and potash salts, less commonly of shale, forming with the halite sedimentary cycles of diverse magnitudes. The Salina Group has been deposited in a basin that had previously received debris from the Taconic orogenic zone. The last orogenic movements had virtually ceased before the deposition of evaporites commenced. The evaporite-bearing sequence is divided into three major cycles by shale suites related to alluvial, fans of debris swept in from the previous orogenic zone. The shale beds are accompanied by dolomite beds containing stromatolitic horizons. The salt contains shale and dolomite beds of diverse thicknesses, giving rise to cycles of varied magnitudes. With increasing distance from the orogenic zone, the thinner shale interbeds in the salt grade into anhydrite. In contrast to the Zechstein sequence, in the Salina Group thicker anhydrite beds are rare and no potash zones have been found. The anhydrite deficiency is attributed by the author to bacterial reduction of the CaSO₄. The H₂S thus formed is in part retained in the sediments, in part it deposited FeS₂ or re-oxidized. The lack of potassium salts indicates a less inhibited communication with the open sea, as also witnessed by repeated incursions of marine fauna. In both sequences, most sedimentary cycles are controlled by the periodic entrance of diluted waters into the basin. Rain water enters directly as well as in the form of terrestrial run-off from the adjacent mountains, introducing mud and foreign ions, diluting and changing the ion ratios of the brines. Sea water enters the basin continuously or periodically, the concentration increases caused by the concomitant inflow of dissolved salts are mitigated by the reflux of more concentrated brines. Abrupt dilution of the brines by sea water followed by slow evaporation produces cycles of progressive solubility in the sediments resembling experimental successions. The periodic entrance of rain and sea water can be controlled by several factors. Increases in rainfall, particularly in the detritus source area, may reflect morphologically or astronomically induced climatic changes; the morphologic factors may in turn be controlled by tectonism, erosion and sediment accumulation. The ingress of sea water can be caused by intermittent subsidence in the bar area, or by a rise of sea level induced tectonically, glacio-eustatically, or simply by a change in wind direction. A few models involving parallel control of terrestrial and marine inflow are presented at the end.

Lower Pennsylvanian, coal-bearing, siliciclastic strata of the central Appalachian foreland basin were deposited in continental to marginal marine environments influenced by high-amplitude relative sea level fluctuations. Sediment was derived from both the low-grade metamorphic terrain of the emergent Alleghanian orogen towards the southeast, and the cratonic Archean Superior Province in the north. Immature sediments derived proximally from the Alleghanian orogen, including sublithic sandstone bodies, were deposited as a southeasterly-thickening clastic wedge within a southeast-northwest oriented transverse drainage system. Texturally and mineralogically mature quartzarenites were deposited in strike-parallel elongate belts along the western periphery of the basin. These mature quartzarenites are braided fluvial in origin and were deposited within northeast-southwest oriented axial drainage head-watered in a northerly cratonic source area. The contemporaneity of transverse and axial fluvial systems defines a trunk--tributary drainage system operating in the central Appalachian foreland basin during the early Pennsylvanian. Detailed analysis of core, gamma ray logs, and cross-sections reveals a hierarchy of bounding discontinuities and architectural elements within the study interval. Discontinuities are both erosional and depositional (condensed) surfaces of interpreted 3rd-order (~ 2.5 Ma) and 4th-order (~ 400 k.y.) origin. Architectural elements within 4th-order sequences consist of upward-fining lowstand and transgressive incised valley fill, alluvial, and estuarine deposits, and upward-coarsening highstand deltaic deposits that are separated by condensed sections. 4th-order sequences are stacked into 3rd-order composite sequences. Sequence stratigraphic architecture in the central Appalachian basin can therefore be attributed to 4th-order Milankovitch orbital eccentricity cycles superimposed on 3rd-order orogenically driven subsidence, or more likely, 4th-order Milankovitch orbital eccentricity cycles superimposed on a lower-frequency eccentricity cycle. The widespread nature of both 3rd- and 4th-order marine flooding zones and sequence boundaries enables both genetic and depositional sequence stratigraphy to be applied to terrigenous to marginal marine coal-bearing strata of the central Appalachian basin. Regionally extensive coal beds occur in close association with both 4th-order condensed sections as well as within highstand deltaic deposits. Formation of coal beds in the central Appalachian basin of southwest Virginia is therefore attributed to both an allocyclic glacio-eustatic mechanism, associated with Milankovitch orbital eccentricity cycles, and autocyclic deltaic processes related to channel avulsion and delta lobe switching. / Master of Science

The lower Pennsylvanian, coal-bearing, siliciclastic strata in Dickenson/Wise counties of southwest Virginia were deposited in continental to marginal marine environments influenced by high-amplitude relative sea level fluctuations. Coal-bearing siliciclastics of the eastern facies belt are fluvio-deltaic in origin, with sediment derived from the erosion of low-grade metamorphic and Grenvillian-Avalonian terranes of the Alleghanian orogen to the southeast. Elongate NNE trending quartzarenite belts in the northwestern region of the basin are braided-fluvial deposits and were sourced by the cratonic Archean Superior Province to the north. This orthogonal relationship between the southeastern coal-bearing siliciclastics and the northwestern quartzarenites reflect a trunk-tributary drainage system operating during the lower Pennsylvanian in the central Appalachian basin. Analysis of core, gamma ray and density logs, and six cross-sections within an approximately 20 km² study area reveals a hierarchy of bounding discontinuities and architectural elements. Discontinuities are both erosional (unconformable) and depositional (condensed) and are 3rd-order (~ 2.5 Ma) and 4th-order (~ 400 k.y.) in origin. Architectural elements are bound by 4th-order discontinuities and consist of upward-fining lowstand and transgressive incised valley fill, alluvial, and estuarine deposits, and upward-coarsening highstand deltaic deposits and represent 4th-order sequences. Lowstand and transgressive deposits are separated from the highstand deposits by marine flooding zones (condensed sections). 4th-order sequences are stacked into composite 3rd-order sequences. Sequence development can be attributed to 4th-order Milankovitch orbital eccentricity cycles superimposed on a lower-frequency eccentricity cycle. Extensive coals occur in both transgressive and highstand systems tracts. Coals within the transgressive systems tract are associated with 4th-order flooding surfaces, while coals within the highstand systems tract occur within high-frequency deltaic autocycles. Therefore, coals formation in the central Appalachian basin can be attributed to be of both allocyclic (glacio-eustacy) and autocyclic (deltaic processes) mechanisms. / Master of Science

Quaternary magnetic studies have provided the conceptual framework to bridge magnetic studies into ancient systems. In cases where environmental materials have been subjected to diagenetic alteration two questions come to mind: 1) What part of the magnetic signal is preserved in the rocks; and 2) can the preserved signal be used to infer/identify magnetic patterns that are characteristic of the depositional, post-depositional, and/or diagenetic environment. Analyses of multi-parameter magnetic experiments conducted on upper Mississippian and lower Pennsylvanian continental successions reveal that distinct depositional, pedogenic, and diagenetic magnetic patterns can be separated and identified. Evidence for a primary depositional signal in several of the upper Mississippian lithofacies is identified by a detrital remanence component attributed to source-area-derived magnetite/titanomagnetite. Red and gray vertisols preserve a Mississippian pedogenic signal characterized by magnetic enrichment, depletion, and amalgamation patterns that are associated with the removal and transport of Fe-rich clays as well as vertical mixing by shrink-swell mechanisms. These well-developed vertisols are interpreted to reflect significant hiatuses in sedimentation associated with prolonged exposure on interfluve/floodplain surfaces that may correlative with incised valleys (lowstand surface of erosion). Similarly, in lower Pennsylvanian quartz arenite facies, early siderite cementation zones as well as conglomerate lags with distinctive magnetic characteristics are thought to reflect periods of prolonged exposure and to define unconformities within compound valley fills. / Master of Science

Silurian strata of eastern North America have been thoroughly studied for nearly two centuries. Through these investigations a general understanding of unit distribution and correlative relationships were established throughout the region. Many of these interpretations remain valid still to this day, however, with advancements in stratigraphic methodologies in the last few decades (e.g., sequence-, chemo-, and biostratigraphy), numerous discrepancies have come to light with regards to the chronostratigraphic correlation of several stratigraphic intervals throughout the region. A number of these discrepancies within the lower Silurian (Llandovery—lower Wenlock) have been resolved in the last two decades permitting the establishment of refined depositional models and sequence stratigraphic hierarchies for strata deposited during this interval of time for the Appalachian, Illinois, and Michigan basins. Though these studies provided significant improvement to the chronostratigraphy of eastern North America, there remained a large under-evaluated stratigraphic interval spanning the remainder of the Silurian (Wenlock—Pridoli), which is host to expansive evaporite reserves and hydrocarbon resources throughout eastern North America. As such, it is critical that these strata are accurately and precisely correlated throughout the region and that temporal constraint be applied to these resources in order to evaluate their potential and develop predictive models for their future utilization. The investigation herein provides high-resolution chronostratigraphic analyses of several core and outcrop from the eastern, southwestern, and western margins of the Appalachian Basin. These analyses included the integration of δ13Ccarb chemostratigraphy, conodont biostratigraphy, sequence stratigraphy, and subsurface geophysical data. The work herein now permits the establishment of global series and stage boundaries for the upper Silurian throughout the Appalachian and Michigan basins and also addresses regional miscorrelations within strata on both the eastern and western margins of the Appalachian Basin to provide a united sequence stratigraphic hierarchy between the Appalachian, Illinois, and Michigan basins.

The environment of deposition of the Ohio Shale of the Appalachian Basin has been studied extensively using various geochemical proxies for each of its members. The accumulation of organic matter (OM) and its preservation in the Late Devonian-Early Mississippian black shales of central Kentucky have been studied extensively, especially the possible correlations between trace metal contents and water-column oxygenation. Previous work has centered on geochemical, petrographic, and isotopic analysis of samples collected throughout the central Appalachian Basin. Mechanisms for OM preservation include high productivity, enhanced preservation due to dysoxic or anoxic bottom waters, and a feedback loop due to high productivity that creates enhanced preservation through the periodic cycling and scavenging of essential nutrients. Usually, a combination of these factors results in the accumulation of enough OM to produce these black shales. This research shows the relationships between trace metal data and the environment of deposition of several cores taken along the eastern side of the Cincinnati Arch in the central Appalachian Basin. Whereas the indices do not all agree in every instance across the breadth of the study area, analyzed together a predominant environment of deposition has been inferred for the shales. The Sunbury Shale and upper part of the Cleveland Member of the Ohio Shale were deposited under euxinic conditions, the lower part of the Cleveland Member was likely euxinic in the northern study region and anoxic throughout the central and southern study areas, whereas the Huron Member of the Ohio Shale was deposited under a range of conditions, from oxic, to dysoxic, to anoxic.