Thesis (M.S.)--Brigham Young University. Dept. of Geology, 2006. / Includes bibliographical references (p. 63-68).

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: David W. Bowen. Includes bibliographical references (leaves 149-162).

The Tuscaloosa Marine Shale (TMS) in southwest Mississippi and south-central Louisiana has potential to become a prolific source of fossil fuels using hydraulic fracturing technology. The objective of this study is to better understand the sequence and regional stratigraphy, lithology, and character of the TMS. Studying the TMS’s lithologic, depositional, and diagenetic properties is essential to maximize potential production. Characterization of the eastern TMS was performed with cuttings from two wells provided by the Mississippi Oil and Gas Board through MDEQ, and two provided by the USGS. Thirty-one petrophysical logs were correlated, to make cross sections and trace sequence stratigraphic intervals within the TMS. Results of the study showed lithologic variability and compaction across the study area, and a sequence stratigraphic correlation of the highstand systems track between the Tuscaloosa and Eagle Ford Groups. This research aims to work toward the greatest potential of the TMS as an unconventional reservoir.

The Upper Mississippian Hinton, Princeton, and Bluestone formations of southern West Virginia constitute a wedge of strata that filled the Appalachian basin over a ~7 million year time interval. Seventeen transgressive-regressive sequences comprise the study interval in the basin depocenter. Five sequence types defined by the degree of incision and the thickness/ character of dominant facies include: 1) major incised valley-fill to coastal plain, 2) major incised valley-fill to deltaic, 3) minor incised valley-fill, 4) coastal plain, and 5) marine-dominated sequences. Transgressive and highstand deposits within several sequences contain tidal rhythmites. The prodeltaic Pride Shale member (Bluestone Formation) preserves a hierarchy of submillimeter-to meter-scale cycles that reflect a spectrum of tidal periodicities. The abbreviated character of these microlaminated rhythmites is suggestive of a distal, subtidal setting wherein neap tides were of insufficient strength to transport sand/ silt. Decimeter-scale bundling of semimonthly cycles is ascribed to seasonal fluvial discharge. Meter-scale, multi-year cycles may reflect the 18.6-year lunar nodal cycle. Sequence development likely reflects fourth-order (~400 k.y.), Gondwanan glacioeustatic cycles. The character and relative stratigraphic position of paleoclimatic indicators within the sequences suggests a link between eustasy and patterns of global-scale atmospheric circulation. Calcic vertisols and lacustrine carbonates in coastal plain successions are suggestive of seasonal, semiarid climatic conditions during highstand progradation. Leached paleosols and coals that underlie sequence boundaries and occur within estuarine fills are suggestive of humid conditions during late highstand through early transgression. This pattern may reflect fluctuations in monsoonal circulation whereby the latitudinal shift of seasonal moisture was restricted to the equatorial zone during glaciations. The fourth-order sequences stack into two (2-4 Ma) composite sequences that consist of: 1) a basal retrogradational interval comprised of a major paleovalley-fill sequence overlain by a thick aggradational sequence set made up of fluvial/ coastal plain sequences (TST); 2) a marine interval that demarcates maximum flooding; and 3)(where preserved) a progradational sequence set consisting of minor incised valley-fill sequences (HST). These composite sequences document accommodation change that may reflect global tectono-eustasy. / Ph. D.

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

Classification of river systems based on dimension and lithology of architectural elements is critical in determining their scale and role in ancient drainages as tributaries, distributaries, or trunk river systems. Facies boundaries associated with the zonation of the fluvio-estuarine system can be difficult to predict using standard facies and sequence stratigraphic models, particularly within broad, long-lived compound incised valley fills. These questions are addressed in an outcrop study of incised valleys in the Turonian Ferron Sandstone Member of the Western Interior Seaway, southern Utah. Field data includes 8 measured sections containing detailed lithological, ichnological, paleocurrent, and architectural data, and 3 high resolution gigapan photomosaics of opposing outcrop faces oriented oblique to depositional dip. The compound valley records multiple episodes of cut and fill, with three nested valleys, each containing multiple channel stories. An upward progression from single thread meandering fluvial style, indicated by large scale laterally accreting point bar deposits, to more freely avulsing rivers in upper stories is documented. Lithological analysis of the oldest valley shows grain size distributions ranging from medium lower sandstone at the valley base to fine lower sandstone towards the top, and is characterized by amalgamated macroform deposits with dune scale crossbedding and abundant mud rip up clasts throughout. The second shows variable estuarine laterally accreting point bars, which coarsen away from the valley margin. The youngest valley is dominated by fining upward successions passing from medium lower dune scale cross bedded sandstone at the base with few mud clasts, to rippled very fine upper sandstone and interfingered floodplain shale deposits. Tidal influence is documented; suggesting that rivers were positioned basinward of the paleo backwater length, and estuarine facies seen in V2 suggests they are within the bayline. These rivers are among the largest documented in the Ferron and show that fluvial style and scale changes regionally within this large valley system. / Thesis / Master of Science (MSc)

No description available.

No description available.

Thirty cores from the Late Jurassic uppermost Jubaila, Arab-D reservoir and Arab-D anhydrite in Hawiyah (Ghawar) and Harmaliyah fields, eastern Saudi Arabia were studied to document the detailed facies stacking and high resolution sequence stratigraphy. The Jubaila-Arab-D interval is a shallowing upward succession of two composite sequences, in which the Arab-D reservoir and overlying anhydrite have up to twelve higher frequency sequences. Both fields are strikingly similar in terms of facies, parasequences, and vertical stacking of facies. The direction of the progrodaion is east and northeast and that is supported by northeast thickening of the Arab-D reservoir and by the stromatoporoid and Cladocoropsis facies progrodation. This suggests that the Arab-D reservoirs in both fields may represent part of a single carbonate ramp with subtle syndepositional highs. The scarcity of exposure surfaces with caliche in the Arab-D reflects the relatively high subsidence rate (~6 cm/k.y.) relative to the small sea level oscillations that formed the succession coupled with the long term shallowing trend up through the section. Dolomites from the Arab-D reservoir zones 1 to 4, in both fields were studied to better understand their origin. The dolomites are dominantly fabric destructive medium to coarse grained types, and much less common fabric retentive finer grained dolomites in the uppermost Arab-D reservoir. The δ¹³C values are rock buffered while the δ¹⁸O values have been greatly shifted toward negative values relative to unaltered early dolomite, and dolomite crystal rims generally have lighter δ¹⁸O values than cores. The dolomites were initiated at different times during shallowing phases on the Arab-D platform, with the bulk of the fabric destructive dolomites forming under near normal salinities, while the fabric preserving dolomites formed as a result of dolomitizing aragonitic sediments from more evaporated waters. With increasing burial and increasing temperature, the early dolomites re-equilibrated with the increasingly warm basinal brines resulting in replacement of cores, and dolomite cementation by rim overgrowth. Progressive plugging of higher dolomites earlier, caused some of these to retain slightly heavier δ¹⁸O values and marine seawater Sr isotope values while those that remained permeable developed very light δ¹⁸O values and more radiogenic Sr values, shifting them toward the field of late stage baroque dolomite. / Ph. D.

A study of 12 cores and 2 wells with cuttings through the Silurian (444 to 416 m..y.) succession of the Wabash Platform, Indiana was done to establish the high resolution sequence stratigraphy of a sediment-starved low-latitude epeiric sea platform during the transition from Ordovician icehouse to Devonian greenhouse. The Wabash Platform (approximately 200,000 square km area) is bounded to the north by the Michigan Basin, to the east by the Appalachian Basin, and passed to the southwest into the Vincennes Basin, which was open to the ocean. Facies developed include: crinoidal grainstone-packstone sheets (updip shoals), buildup facies (stromatactis wackestone - lime mudstone, below storm wave-base settings; stromatoporoid skeletal wackestone - floatstone, storm wave-base to fair-weather wave-base; and crinoidal rudstone to packstone; flank facies); non-cherty, skeletal packstone, wackestone, mudstone (sub-fair-weather- to storm wave-base); and cherty, skeletal wackestone - mudstone and variably argillaceous carbonate mudstone (below storm wave-base). Eight thin sequences (1.3 to 4 m.y. duration) occur and range from 2 m to 10 m, with the upper two sequences up to 20 m downdip; most of the sequences can be correlated to global cycles. Except for the lower three disconformity-bounded sequences, most sequences are relatively conformable and lack well defined sequence boundaries or subaerial exposure surfaces. The most easily mapped surfaces are the transgressive surfaces, given that the correlative conformities are cryptic. Lowstand system tracts probably include downdip grainy facies and the deep ramp seaward of updip late highstand deposits. Transgressive systems tracts are upward deepening, upward fining carbonate units, some of which become more argillaceous and silty upward. This contrasts with the usual association of clastic-prone units with lowstand to early transgressive systems tracts. Highstand systems tracts are subtly upward coarsening from carbonate mudstone to skeletal wackestone/packstone and rarely skeletal grainstone. During deposition of the uppermost two sequences, mudmound barrier banks grew upward into shallow water buildups to form a discontinuous raised rim (40 m relief) to the ramp. Even though subsidence rates were very low (<1 cm/k.y.), the low sedimentation rates (0.3 cm/k.y. to 0.8 cm/k.y.) generally prevented the seafloor from building to sea level except for the basal three sequences in which Early Silurian third order glacio-eustacy generated disconformable boundaries. Thus the ramp remained subtidal through most of the relatively ice-free greenhouse later Silurian except over the buildups which locally shallowed to sea level. Parasequence development in high accommodation settings elsewhere in North America are compatible with the transition from moderate ice-sheets to an ice free world. However, this is poorly expressed on the Wabash Platform due to the dominantly deeper subtidal setting. The Silurian provides a window into climate change from a global cool period to global hothouse, which may have implications for understanding future climate change. / Master of Science