<p> Eleven facies types, distinguished on the basis of internal grain size and primary sedimentary structure, were obsereved at the central region of the Brampton esker. These facies were then used to perform an empirical test of H.C. Saunderson's model of eskerine sedimentation for this part of the esker. Primarily, the vertical sequence of facies consisted of: (a) cross-bedded gravel representing the front of a prograding delta; (b) delta-front sands that are poorly sorted and characterized by massive structure and parallel lamination; (c) cross-bedded coarse sand recording the migration of sand waves across the topset; (d) trough-shaped cross-laminae of fine sand indicating current ripple migration on top of the sand waves; (e) draped lamination grading into cross-laminae of fine sand showing stoss-side preservation as the ratio of suspended sediment to bed load decreased; and (f) thick layers of silt and clay deposited in stagnant water conditions brought about by delta abandonment. Cut-and-fill structures were also present, giving evidence of distributary channels traversing the delta. </p> <p> Saunderson's model adequately explains the origin of sediments in the central region of the esker, but some modifications were made on the basis of new evidence revealed by a recently uncovered exposure. </p> <p> The sedimentary enviroment was that of a delta which consisted of a topset network of distributary channels prograding into a glaciolacustrine enviroment. / Thesis / Candidate in Philosophy

<p> The Lower Cretaceous (Albian) Viking Formation at Harmattan East and Crossfield, Alberta, contains two regionally extensive erosion surfaces, VE3 and VE4, separating three allomembers, A-B, D and E. These erosion surfaces can be mapped over large areas of the Alberta basin allowing for the creation of a Viking allostratigraphy. </p> <p> The allostratigraphic base of the Viking alloformation in the study area is informally designated BV. The BV log marker is overlain by allomember A-B, which in turn is overlain by the regionally extensive ravinement surface VE3. The VE3 surface is sharply overlain by allomember D, a northeastward thinning clastic wedge composed of storm dominated facies and nonmarine deposits. Allomember D is in turn overlain by the regionally extensive ravinement surface VE4. Allomember E, which overlies this unconformity is a complex succession of coarse grained facies interbedded with dark mudstones. The upper . part of allomember E is composed of dark mudstones bounded at the top by a regionally extensive condensed section (Base of Fish Scales) that informally marks the allostratigraphic top of the Viking alloformation in the study area. </p> <p> Viking sedimentation began with the deposition of basinal and offshore transitional mudstones, siltstones and sandstones of allomember A-B. A major drop in sea level allowed valleys to incise into these sediments. Nonmarine and upper shoreface deposits of allomember A-B were eroded at Harmattan East during the ensuing transgression that produced the VE3 ravinement surface. A second relative sea level lowering resulted in northeastward progradation of allomember D. Renewed transgression modified the older subaerial erosion surface on top of allomember D, forming the marine ravinement surface VE4 and the overlying deposits of allomember E. Multiple stillstands or slow rates of transgression produced the "steplike" southwestward climbing morphology on the VE4 surface. Fluvial systems supplied coarse sediment to each shoreface incision ("step"). During minor sea level falls, storm and tidal currents reworked sediment at these shorefaces and also transported sediment basinward over older "stepped" shorelines forming onlap markers EO to E5. Continued transgression blanketed the coarse grained interbeds with offshore dark mudstones (Colorado Shale). A major pause in basin deposition led to the formation of a condensed section of fish skeletal remains (Base of Fish Scales). The base of this unit marks the end of Viking depostion in the study area. </p> <p> The Harmattan East Viking oil field is producing from the coarse grained transgressive lag that overlies VE4. It is separated from Caroline field (along depositional strike) by a rise in the VE4 surface. </p> / Thesis / Master of Science (MSc)

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No description available.

Fine grained sediments were common in epicontinental seas, with shallow slopes, such as the Cretaceous Western Interior Seaway. However, proposed mechanisms for offshore mud transport, such as turbidity currents, tempestites, and hyperpycnal flows, require significant slopes. A core from the Upper Mancos Shale, Mancos C, located in the San Juan Basin of New Mexico was analysed to determine the dominant transport processes bringing sediment offshore. A detailed facies analysis was conducted, over 54 m of slabbed core, using sedimentological data, such as grain size, type of sedimentary structures, bed thickness, lithology, clay content, fossils, ichnofacies, and degree of bioturbation. The facies observed in the core show that multiple processes, including ignitive turbidity currents, hypopycnal and hyperpycnal flows, and tempestites, were responsible for the deposition of the Mancos C core. The resuspension of mud on the inner shelf by storm waves also played a key role in moving mud further offshore. Tidal influence within the Mancos C was relatively small. / Thesis / Master of Science (MSc)

Fine-grained clastic sediments make up the gross lithology in interior basins of ancient epicontinental seas, such as the Cretaceous Western Interior Seaway. This study provides a high-resolution thin-bedded facies analysis and regional correlations to determine how the heterolithic units of the Juana Lopez Member of the Mancos Shale were transported and deposited in the San Juan Basin. Data for this study was obtained from outcrop observations in eleven measured sections, spanning a distance of 115 kilometers. Eleven facies are observed, four sequences and eleven parasequence sets are identified. A depositional model is determined through the high-resolution facies analysis, which suggests deposition on a proximal to distal mudbelt through multiple processes, including turbidity currents, hypopycnal plumes, wave enhanced sediment gravity flows (WESGFs), storm surges, tides and oceanic currents. Overall, the Juana Lopez is dominated by upward-shoaling parasequence sets, with an increasing number and thickness of sandstone dominated bedsets, suggesting regressive sedimentation with distal expressions of transgression found in two parasequence sets. The source of sediment is determined through 520 paleocurrent measurements and plaeogeographic data, and is determined to be transported by along-shelf currents, dominantly from proximal NE clastic wedges. / Thesis / Master of Science (MSc)

A field and textural investigation of the Medina Formation has been made. The thesis includes a brief analysis of the microscopic sedimentological properties of the sandy facies, a detailed study of the paleocurrent indicators, and a study of the distribution of the more typical sedimentary structures. Analytical laboratory data, primary sedimentary structures, and outcrop data have been used to reconstruct the paleoenvironmental setting of the Lower Silurian rocks exposed along the Niagara Escarpment from Hamilton (Ontario) to Fulton (New York). They indicate a complex of sub-environments within the broad model of a delta, with the direction of current movement being from the South-East in the eastern part of the area under study and from South-West and North-East in the western part. The determination of these two paleocurrent systems forms a major contribution of this work. / Thesis / Doctor of Philosophy (PhD)

In order to improve our understanding of present and future coastal environmental change, we look into the past using sediment that accumulates in coastal environments. We have done this for two disparate systems: a back-barrier lagoon in southwestern Japan, and freshwater tidal marshes along the Hudson River, New York, USA. In Japan, we used a 2,500-year sediment record to investigate coastal flood risk from tsunamis and typhoons. This is a critical area of study to better understand the spatial and temporal variability of these hazards in Japan. In the Hudson River we looked at modern (since 1800) deposition of sediment in anthropogenically constructed embayments that have formed tidal wetlands in the last few centuries. A better understanding of the factors that have attributed to these successful tidal marsh systems in the past can help inform future management decisions in the face of future sea level rise. Studying the history of coastal systems using the sediment record is a valuable tool for assessing hazard risk and habitat loss in the present and future.

The Late Triassic platform carbonates of the Transdanubian Range, Hungary were part of a passive margin platform at the southwestern end of the Triassic Tethys now occurs in a single fault-bounded terrain. The Hungarian platform is made up of meter-scale, precessional (~20 k.y.) carbonate cycles. It contains a lower unit, the Main Dolomite Formation (600-1500m thick), which is totally dolomitized. It is overlain by the Transitional Unit (150-400m thick). The overlying Dachstein Limestone is up to 800m thick. The platform is a cyclic succession of subtidal carbonate, laminated tidal flat limestone or dolomitic caps, and reddish or greenish paleosols or reworked paleosols. The Triassic was a time of global greenhouse conditions and Milankovitch climate forcing has been well documented from lakes and off-shelf facies. The Triassic Hungarian carbonate platform records an imperfect Milankovitch eustatic signal. They lack the bundling of 5 precessional cycles into 100 k.y. eccentricity cycles or 20 cycles/400 k.y. bundle. This is interpreted to be due to many missed beats evidenced by caliches and paleosols, and thick amalgamated subtidal carbonates. These result from precessional sea-level fluctuations either not flooding the platform, or flooding it too deeply to allow shallowing up to sea-level in one precessional beat. Spectral analysis of the Hungarian carbonates was used to compare the amplitude spectra of different time series including lithology, gamma ray, self potential and neutron density. The spectra based on lithology were compared to synthetic spectra generated by computer from platforms subjected differing Milankovitch signals. Most dolomitization of the Hungarian carbonates occurred early in tidal flat settinfs during each high frequency cycle. Intertidal-supratidal dolomites are fine grained, Fe²⁺ and Mn²⁺ rich and slightly enriched in δ¹⁸O compared marine calcite cement, and formed from weakly to moderately reducing marine waters. Subtidal dolomites are slightly coarser grained, low in Fe²⁺ and Mn²⁺ and have heaviest d¹⁸O signatures, indicating more evaporative oxidizing brines beneath flats. Repeated emergence stabilized the dolomites to low Sr²⁺ and Na⁺ types similar to Cenozoic dolomites. Later, coarse-grained dolomites with very low Mn²⁺ Fe²⁺ and light δ¹⁸O signatures were formed along the platform margin by thermally driven, warm oxidizing marine water associated with Jurassic rifting of the Pennini Ocean (Neo-Tethys). The overall vertical distribution of early dolomite on the platform does not reflect long term ecstasy. Instead the regional stratigraphic trends in climatically sensitive sediments, as well as stable isotopes, suggest that intense dolomitization of the lower platform reflects a semi-arid, hot subtropical setting and megamonsoonal climate. Global cooling and increased humidity toward the latest Triassic and Early Jurassic, inhibited pervasive early dolomitization, leaving the upper platform little dolomitized. / Ph. D.

The Triassic Cow Branch Formation of the Dan River Basin is host to a world-class lagerstätte deposit of exceptionally preserved insects, among other organisms. The lagerstätte occurs within a cyclic, lacustrine sedimentary succession, hypothesized to have been driven by Milankovitch climate forcing. Through an integrated sedimentological and geochemical investigation, I present evidence that the lagerstätte was deposited during a lake transgression, under intermittently anoxic and ferruginous conditions. Sedimentological evidence shows a deepening followed by shoaling through a broad fining and subsequent coarsening of the sedimentary units of the sequence. This transition in grain size occurs at the lagerstätte. Despite relatively quartz-rich sediments sourced to the basin, silica-content in the studied cycle is exceptionally low. The replacement of silica by the zeolite mineral analcime, coupled with primary dolomite precipitation suggests alkaline lake water. Geochemical evidence, including total organic carbon (TOC), pyrite sulfur and iron speciation data suggest anoxic, ferruginous waters. At the lagerstätte interval, TOC content increases significantly, coinciding with the presence of darker, more laminated sedimentary lithofacies. At the interval of the highest TOC content, a spike in pyrite sulfur content occurs; likely the result of slowed sedimentation. Organic carbon-to-pyrite sulfur ratios suggest however, that the lake water was sulfate-poor and the deep waters never became euxinic (anoxic, H2S-containing). Iron proxy data show that the studied portion of the Cow Branch Formation deposited under intermittent to persistent anoxic conditions. These data suggest a confluence of factors — lake transgression, combined with alkaline and anoxic, ferruginous water chemistry — created an ideal scenario that led to lagerstätte formation. / Master of Science