Soil seed banks are important to the maintenance and restoration of floras. Extant seed banks exhibit unique characteristics with regard to the distribution of seed size and seed density. Seeds were recovered from the Upper Pennsylvanian Wise Formation in southwest Virginia. Structurally preserved seeds were also examined from coal balls of the Pennsylvanian Pottsville and Allegheny Groups, Ohio. The size distribution of the seeds from the Wise Formation is similar to that of structurally preserved seeds of the Upper Pennsylvanian Pottsville and Allegheny Group coal balls. In contrast, the seed size distributions in extant wetland, grassland, woodland and forest habitats are significantly narrower than that of seeds from the Pennsylvanian seed banks. Larger seeds are less dependent on light for germination, and aid in seedling establishment more than smaller seeds, especially in dense stable forests where disturbance events are rare. Large seed size may contribute to increased seed longevity, which reduces the effect of environmental variability on seed germination and development. The significantly larger size of the Palaeozoic seeds may have imparted an advantage for seedling establishment in the dense Palaeozoic forests. The preponderance of large seeds may be a result of the absence of large seed predators (e.g. herbivorous tetrapods), and may have been an evolutionary strategy to minimize damage to the embryo from a predator population dominated by small invertebrates with chewing or sucking mouthparts. The estimated seed density of 192 seeds/m2 in the Palaeozoic seed bank falls within the range of modern seed banks, but at the lower end of modern seed bank densities in a variety of habitats.

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

An enhanced coal-bed methane facility in Russell County, Virginia is targeting lower Pennsylvanian coals for CO2 storage, but the shallow sandstone units intercalated with the coals may also prove to be potential CO2 reservoirs, since the injection apparatus is already in place. Using samples from a continuous core in southwestern Virginia, this detailed review of the petrography and local volume of the Breathitt Formation sandstone units examines their diagenetic alterations in order to assess the units' reservoir quality. The high-frequency sequences of immature sandstones, heterolithics, shales and coals in Russell County represent deposits from the transverse fluvial facies association of a broad braided-fluvial drainage system in the central Appalachian Basin. The sandstone units within these sequences are laterally extensive, maintaining similar thickness and gamma ray signature across the study area. Lower Pennsylvanian sandstone units are consistently sublitharenite with a diagenetic mineral assemblage including siderite, chlorite, kaolinite, albite, illite, silica and calcite. Primary porosity is not preserved, but secondary porosity (5 ± 3.1 %) has developed at the expense of feldspars and unstable lithic fragments. Permeability assessments collected in Grimm (2010) measured impervious values (0.005-0.008mD) for the medium-coarse grained sublitharenites. At the temperatures and pressures present within these units, CO₂ is unlikely to react with either the primary or diagenetic mineralogy in a way that negatively impacts continued injection on human time scales. Low pore volume and permeability due to the timing of certain authigenic mineral emplacement are the main hindrance to reservoir quality. Lower Pennsylvanian sandstones are not viable potential reservoirs for carbon sequestration. / Master of Science

Carbon dioxide sequestration in coal-bed methane fields has potential to add significant recoverable reserves and extend the production life of coal-bed methane fields while at the same time providing a geologic sink for atmospheric greenhouse gases. The ability to relate the thickness, extent, and quality of coal seams to their relative position within a sequence is fundamental in determining the sequestration potential of a geologic formation. This thesis documents the carbon dioxide storage capacity and enhanced coalbed methane recovery of lower Pennsylvanian coal-bearing siliciclastic strata within the Bradshaw CBM field, southern McDowell County, WV. Analysis of outcrop, gamma ray and density logs, and eight cross-sections within the study area reveals a hierarchy of bounding discontinuities and architectural elements. Discontinuities are both erosional (unconformable) and depositional (condensed) surfaces of 3rd-order (~2.5 Ma) and 4th-order (~400 k.y.) origin. Architectural elements bound by 4th-order erosional discontinuities consist of upward-fining lowstand and transgressive incised valley fill, alluvial, and estuarine deposits, and upward-coarsening highstand deltaic deposits, representing 4th-order sequences. 4th-order sequences are stacked into composite 3rd-order sequences. Sequence development is attributed to higher frequency (~400 k.y.) 4th-order Milankovitch orbital eccentricity cycles superimposed on lower frequence (~2.5 Ma) orbital eccentricity cycles. Coal seams occur in the transgressive and highstand systems tracts, associated with 4th-order flooding surfaces and high-frequency deltaic autocycles, respectively. Transgressive coal-bed development is attributed to Milankovitch driven glacio-eustacy while highstand coal-bed development is attributed to autocyclic deltaic influences. Assessment of carbon dioxide storage capacity within coals of the lower Pennsylvanian Pocahontas and Bottom Creek formations in the Bradshaw CBM field indicates that 19 million tons of carbon dioxide can be sequestered. Sequestration of carbon dioxide within the Bradshaw CBM field has the potential to increase coal-bed methane recovery by as much as 52 billion cubic feet. / 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

No description available.

No description available.

Call number: LD2668 .T4 1986 B57 / Master of Science / Geology

No description available.

A Formação Piauí registra a deposição de um sistema eólico, fluvial e marinho raso acumulado em uma bacia de sinéclise intracratônica. A caracterização das associações de fácies e do arcabouço estratigráfico foi feito através de uma descrição detalhada das fácies sedimentares e levantamento de perfis de afloramentos. As fácies foram classificadas de acordo com a textura dos grãos (tamanho e seleção) e estruturas sedimentares observadas. Medidas de paleocorrentes foram feitas nas estratificações e laminações cruzadas. Os perfis foram medidos na escala 1:50 em locais com boa exposição vertical. Seis associações de fácies foram reconhecidas, dunas e interdunas eólicas, lençóis de areia eólicos, canais fluviais, canais fluviais influenciados por maré, shoreface superior e shoreface inferior. Através da correlação das superfícies estratigráficas as associações de fácies foram organizadas em tratos de sistema, que formaram oito sequências deposicionais de alta frequência, delimitados por discordâncias subaéreas. Estas sequências são compostas por um trato de sistemas de nível baixo (TSNB), que é dominado por sistemas eólicos ou fluviais, um trato de sistemas transgressivo (TST), que é formado por canais fluviais influenciados por maré e/ou depósitos de shoreface superior e inferior com empilhamento retrogradacional, e um trato de sistemas de nível alto (TSNA), que é formado por depósitos de shoreface superior e inferior com empilhamento progradacional. Duas sequências deposicionais de mais baixa frequência foram determinadas ao observar o empilhamento das sequências de alta frequência. Ambas as sequências são formadas por uma regressão inicial seguida por uma transgressão progressiva. O principal controle das variações no nível relativo do mar durante a acumulação da Formação Piauí foi glacio-eustático. Contudo, mudanças climáticas estavam associadas com as fases glacio-eustáticas e influenciaram a deposição eólica e fluvial. / The Piauí Formation records the deposition of aeolian, fluvial and shallow marine systems accumulated in a cratonic sag basin. Characterization of the facies associations and sequence stratigraphic framework was done by detailed description of sedimentary facies and logging of outcrops. The facies were classified based on grain texture (size and selection) and sedimentary structures observed. Paleocurrent orientations were measured from cross-strata. Stratigraphic sections were measured at a 1:50 scale at outcrops with good vertical exposure. Six facies associations were recognized: aeolian dunes and interdunes, aeolian sandsheets, fluvial channels, tidally-influenced fluvial channels, upper shoreface and lower shoreface. Through correlation of stratigraphic surfaces the facies associations were organized in system tracts, which formed eight high frequency depositional sequences, bounded by subaerial unconformities. These sequences are composed of a lowstand system tract (LST), that is aeolian-dominated or fluvial-dominated, a transgressive system tract (TST) that is formed by tidally-influenced fluvial channels and/or upper and lower shoreface deposits with retrogradational stacking, and a highstand system tract (HST), which is formed by lower and upper shoreface deposits with progradational stacking. Two low frequency cycles were determined by observing the stacking of the high frequency cycles. Both sequences are formed by an initial regression followed by a progressive transgression. The main control on sedimentation in Piauí Formation was glacioeustasy, which was responsible for the changes in relative sea level. Even though, climate changes were associated with glacioeustatic phases and influenced the aeolian and fluvial deposition.