The recent geomorphologic history of the Apalachicola River can be related to local changes in sea level and the sediment output of the river. These changes can be observed in seismic data and boreholes collected in the bay. This project employed seismic, borehole and geochronologic data in order to map and better understand the paleogeography of the Apalachicola River and Bay region. These maps include; the seabed, the top of a mid-Holocene stratigraphic unit, the top of the Pleistocene, the top of the uppermost Mio-Pliocene unit, which includes a karst surface. In addition, Holocene-aged fluvial paleo-channels and paleo-deltas were identified in the subsurface and their paleogeographic relationships were mapped. The uppermost Mio-Pliocene aged sedimentary unit was described by Schnable (1966) on the basis of borehole data, as primarily sandy and clayey limestones, known as the Choctawhatchee Formation (Schnable, 1966). Huddlestun (1976) later described the same unit as the Intracoastal Formation, due to its location in the Intracoastal Waterway. Schmidt (1984) described the Intracoastal Formation as an easily recognizable stratigraphic unit composed of sandy, highly microfossliferous calcarenitic limestone. The thickness and dip of the Intracoastal Formation varies widely over the Apalachicola River region, due to the influence of the regions's largest subsurface structure, the Apalachicola Embayment (Schmidt, 1984). The embayment dates back to the early Tertiary and is the result of regional tectonic forces. The embayment is located between the Chatahoochee Anticline to the west and the Ocala Platform to the east (Rupert, 1997). The northern end of the Apalachicola Embayment narrows and extends into the Gulf Trough in southern Georgia (Rupert, 1997). It widens and deepens as it extends into the modern Gulf of Mexico (Rupert, 1997). The southernmost extent of the embayment is not well established due to the lack of offshore well data (Schmidt, 1984). The early to mid-Holocene paleo-deltaic features beneath the modern estuary migrated from west to east over the last approximately 7000 years. The specific subsurface features were identified and located by use of both seismic data and vibrocore logs. The depth of the features observed in the seismic data was calibrated based on bridge borehole transects collected from the Eastpoint to Apalachicola and the Apalachicola to St George Island bridge-causeways. The Apalachicola River's paleo-discharge was determined by using the Manning equation to calculate the maximum discharge of the river, based on the channel geometry and regional gradient. Several paleochannel profiles were found and measured. The calculated paleo-discharge was 86,000 cfs. This discharge was based on the entire cross-section of the river and therefore represents a bank-full or maximum discharge. The modern and paleo-streamflow were found to be comparable. The calculated paleo-discharge value falls within the range of the average annual peak discharge of the modern Apalachicola over the last 30 years. A possible explanation comes from Holocene climate data extracted from the palynology of long cores from regional lakes. Data from two lakes indicates that climate in the region has changed little in the past 6,000 years and perhaps for as much as 8,000 years. The paleofluvial history of the region's largest river, the Apalachicola, appears to corroborate that finding. / A Thesis Submitted to the Department of Geological Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Fall semester, 2008. / November 24, 2008. / Geomorphology, Apalachicola Bay, Florida, Seismic, Discharge, Delta, Karst / Includes bibliographical references. / Joseph F. Donoghue, Professor Directing Thesis; Lynn Dudley, Committee Member; Bill Hu, Committee Member.

Poverty Bay is a small embayment located in the middle of the Waipaoa River Sedimentary Dispersal System (WSS) on the eastern coast of the north island of New Zealand. Within this dispersal system, a large multidisciplinary study was focused on determining the sediment routing from the source within the headwaters to the locations of sediment accumulation on the continental shelf and slope. Poverty Bay acts as the land to sea transition area in the WSS, and as such significantly modifies the fluvial sedimentary signal before it is exported to the continental shelf. Until this study, little hydrodynamic or sediment-transport work had been conducted in Poverty Bay, however. This dissertation analyzed observation and numerical model results to characterize the hydrodynamics and sediment-transport within Poverty Bay. Three S4 current meters with pressure and temperature/salinity sensors, one upward looking ADCP, and one downward looking ADV were deployed in Poverty Bay for April--September, 2006. Hydrodynamics, sediment-transport, and waves were modeled using the Regional Ocean Modeling System (ROMS) fully coupled to the Simulated WAves Nearshore (SWAN) model. The 2006 winter wet season was modeled to overlap with the field observations, along with a ∼40 yr recurrence interval storm that occurred from 21--23 October, 2005. For these two meteorological conditions, four different model grid and sediment load configurations were modeled; (1) the modern Poverty Bay with the modern sediment load, (2) the modern Poverty Bay with the pre-anthropogenic (PA) sediment load, (3) the 2 kya Poverty Bay with the PA sediment load, and (4) the 7 kya Poverty Bay with the PA sediment load. Both the observation and modeling results showed significant quantities of fine sediment were ephemerally deposited within the shallow Poverty Bay during times of elevated river discharge and energetic waves and currents. The deposition of sediment within Poverty Bay during floods followed by the resuspension and export to the continental shelf during subsequent wave events created multiple pulses of sediment out of Poverty Bay. as the sediment underwent multiple resuspension episodes, the sedimentary signal initially supplied by the river, such as the timing of supply to the shelf and the grain size distribution, would be altered. Shoreward nearshore currents and a divergence in the currents seaward of the Waipaoa River mouth provided mechanisms for the segregation of the sand from the muddy sediment, with the coarse sediment preferentially moved shoreward and the fine sediment exported from Poverty Bay to deeper water. Model results also showed significant differences between the sedimentary signals supplied to the continental shelf based on the dispersal basin geometry and river mouth orientation. The model estimates showed that marine dispersal can influence the long-term trends of a slowing shoreline progradation rate and coarsening upward sequences on the continental shelf, without invoking climate change or changes to the sediment supply. This implies that the processes controlling marine and nearshore sediment dispersal must be considered when developing hypothesis based on sedimentological observations.

Abstract Multiple proxy analysis of lake sediment records are crucial for understanding changes in environmental and climate conditions over historical and geological time. Most recently, the use of biomarker proxies coupled with sedimentological investigations provides a new approach for gaining insight into the lake processes that capture information about past climate change. This approach is applied here to better understand the paleoclimate record from Lake El’gygytgyn in Western Beringia. Multiple organic geochemical compound concentrations were measure as proxies for both aquatic and terrestrial biological productivity. Measurements of n-alkane (plant leaf waxes) as well as concentrations of the compounds arborinol (marker for trees), dinosterol (dinoflagellates), and long chain (C28 – C32) 1,15 n-alkyl diols (eustigmatophyte algae) demonstrate warming conditions around Lake El’gygytgyn during MIS 9 and MIS 11, especially when compared to diatom production and palynological investigations from Melles et al. (2012). These time periods illustrate the presence of extensive forest cover as well as elevated concentrations of all aquatic biomarkers analyzed, corroborating their “super interglacial” designation. Analysis of branched glycerol dialkyl glycerol tetraethers, a relatively new proxy used to estimate mean annual temperatures and soil pH, was applied also suggesting warming conditions during MIS 9 and MIS 11, although further calibration techniques are needed to accurately estimate temperature changes. Sedimentological results include the analysis of bulk mineralogy, clay mineralogy, iron oxide, and color measurements for the same MIS 8 through MIS 12 interval. The hue color parameter, measured from high resolution core scans, suggests a link to global climate records, with green sediments reflective of cold intervals and red sediments indicative of warmer climate conditions. Validation of the color record was done in part by analyzing the clay mineralogy and the abundances of clay minerals. These data show that clay deposition dominates interglacial periods. Moreover the clay polytypes can be linked to bedrock weathering. Bulk mineralogy measurements allow for the reconstruction of synthetic color spectra which link mineralogy to sediment color. Overprinted on the mineralogical color signal is red color staining from iron oxide minerals, formed within the catchment during wet intervals when increasing amounts of eroded Fe – bearing silicate minerals are available for oxidation. If true, interpretation of the hue record then suggests hue is a proxy for wet/dry conditions within the lake, and when paired with the biomarker analysis shows significant warmer and wetter conditions during MIS 9 and 11. However, the hue record also demonstrates notable variability outside of these two interglacial periods, not recognized by other proxies, are not currently well understood. Overall, the multi-proxy results from this work can be further applied to the longer temporal scale of the Lake El’gygytgyn sediment core, and potentially elucidate climate changes deeper into the Pleistocene, and even into the Pliocene portions of the sediment record.

The Lower Devonian (Deerparkian) Oriskany Group in eastern Pennsylvania has been shown to have been deposited under conditions of marine regression (Epstein etal, 1967). This study integrates field evidence and cumulative size ­frequency dat a in an investigation of the stratigraphic expression of marine regression. Lower Devonian paleogeo­graphy is interpreted, and the central Appalachian Basin shore line is adjusted from recently published maps (Boucot, 1968; Head, 1969) to include a land ·mass near Andreas, Pa. The Oriskany Group in eastern Pennsylvania is divided into three lithologic units based on bedding sequence, sed­imentary textures, and sedimentary structures. Lithologic unit one is a sequence of poorly bedded silty shales and siliceous argillaceous limestones which thickens to the northeast. The unit is interpreted as occupying an environmental position offshore and below wave base. Lithologic unit two is a sequence of thinly bedded coarse sandstones disconformably overlying, and interbedded with, rocks identical to those in unit one. Unit two represents depo­sition of sand by ripple trains or sand waves during storms in near (but below) -wave base environments of unit one. Lithologic unit three is a sequence of thick bedded sandstones which were deposited in a nearshore bar and beach environment. Analysis of cumulative size-frequency data supports the contention of Spencer (1963), that all sediments are mixtures of two or three log-normally distributed populations of sediment, and that sorting can only be defined by the degree of truncation of the size-frequency curve. Although the Oriskany is usually called a well sorted sand, only sand beds from Kunkletown (interpreted as the most nearshore of the three sections studied) show any evidence of sorting based on the above definition. Sand beds become coarser in a nearshore direction, but wide vertical fluctuations in coarseness measures· are present in any one section. The sequence of lithologies, textures, and structures of the Oriskany Group of eastern Pennsylvania are suggested as a model of the condition of marine regression. / Earth and Environmental Science

The southern coast of Alaska is a climatically sensitive and tectonically active region, however due to its remoteness and harsh climate there are limited long-term historical records of environmental conditions such as storm frequency, river discharge, and earthquakes. In order to determine the potential for Prince William Sound sediments to contain high-resolution paleorecords of these conditions, a suite of 11 gravity cores was collected within the Sound in order to determine the modern day sediment depositional trends and to develop elemental proxies for earthquakes and seasonal sedimentation. 210Pb/137Cs-derived sedimentation rates and grain size trends indicate that there are two distinct sediment sources to the Sound; an allochthonous source of sediment that is advected into the Sound through Hinchinbrook Entrance, and an autochthonous source of sediment from the Columbia Glacier region of the northern Sound. Cyclic variations in grain size were identified in Hinchinbrook Entrance sediments using the XRF Sr/Pb ratio and were interpreted to be the result of seasonal sedimentation; with coarse-grained sediments deposited during the winter when storm-driven wave and currents in the nearshore region are high, and fine-grained sediments deposited during the summer when costal conditions are less energetic and when the discharge and transport of sediments from the Copper River is high. Additionally, light and dark colored laminations in northern Hinchinbrook Entrance sediments were interpreted to be the result of seasonal variations in the supply and preservation of organic matter; with high concentrations of organic matter preserved in the summer when primary production, the flux of terrestrial organic matter from rivers, and costal upwelling of potentially low oxygenated waters is high, and low organic matter concentrations preserved in the winter when primary production and river discharge are low, and when downwelling conditions likely introduce highly oxygenated waters. The use of the XRF Br/Cl ratio as a proxy for marine organic matter suggested that at least a portion of the dark, organic-rich, summer deposits had a marine origin, and may therefore be a potential proxy for seasonal sedimentation under certain conditions. Gravity flow deposits from the northern Sound were identified as having a source from the Columbia Glacier region using the XRF K/Ca ratio. The gravity flows that caused these deposits were identified as being triggered by historically recorded earthquakes, which likely remobilized sediment on the steep slopes of the northern channel and which then flowed downslope to the south. The results of this study indicate that the rapidly accumulating sediments in Hinchinbrook Entrance potentially contain high resolution records of Copper River discharge, storm activity and primary production, whereas sediments in the northern Sound may contain a regional seismic record.

A sediment transport model within the Regional Ocean Modeling System (ROMS) was used to examine how repeated cycles of deposition, erosion, and bioturbation influence flood and storm event bed character offshore of a significant fluvial source. Short-lived radioisotopes Beryllium-7 (7Be) and Thorium-234 (234Th) can be used as tracers of deposition and reworking on the continental shelf, and modeled profiles of these radioisotopes, along with simulated profiles of sediment bed grain size distributions, were analyzed for various model runs.The presence of an atmospherically derived radionuclide,7Be, in seafloor sedimentindicates terrestrial (riverine derived) sediment deposition offshore of a fluvial source.In contrast,234Th naturally occurs in seawater through the decay of its generally conservative parent, 238U, and its presence in the seabed indicates the recent suspension of sediment in oceanographic water. Simulated profiles of 7Be and 234Th weredirectly related to the flood and storm sequences used as model input.The model results showedthat the radioisotopic profiles are sensitive to the timing of 7Be input, phasing of wave and current energy, and intensity of bioturbation; complicating the relationship between simulated profiles andmodel input of flood and hydrodynamic forcing. Sediment grain size and geochronological tracers were used as markers of event beds for flood and storm deposition scenarios.

Karstic cave systems are intricately related to surficial processes and the study of cave sediments is a growing field of research. Sediment deposits in caves are protected from surficial weathering processes, and are therefore often preserved. Cave sediments have applications in studies for paleoclimatic reconstruction, contaminant transport, and paleoflood and stream incision rates, making them valuable contributors to other areas of geoscience. Hidden River Cave is an active, multi-level cave system in the town of Horse Cave, Kentucky with over 33 km of mapped passages. A history of anthropogenic impacts on the cave system include uses for hydroelectric power generation, a water source, and a show cave until it closed in 1943 due to severe contamination from domestic and industrial waste. This study reports on the analysis of sediment cores collected from the cave system which show distinct concentrations of metals within the sediment from chrome plating plant effluent. Relative concentrations of metals in the core record were obtained using an ITRAX core scanner, and were observed to decrease moving downstream from the chrome plating plant contamination source. Sediment core analysis allows depositional patterns in the cave system to be observed and related to historic surficial processes. The chronology of sedimentation events was determined using Pb-210 analysis of core sediment and indicates a strong connection between historical contaminating events in the town of Horse Cave and cave sediment deposition. Sediment core analysis has thus allowed depositional patterns in the cave system to be determined and related to historic surficial processes. These findings can be applied to enhance understanding of the combined effects of landscape evolution and anthropogenic impacts which may be used to inform decision making processes for communities overlying both Hidden River Cave and other karstic cave systems. / Thesis / Master of Science (MSc)

The Jurassic Tilje Formation located on the Norwegian continental shelf contains many thick (>10 mm) and macroscopically homogenous mudstone layers. These mudstone layers are interpreted to have accumulated rapidly from “fluid-mud,” a highly concentrated aqueous suspension of fine-grained sediment. Fluid muds in the Tilje are recognized in tidal-fluvial channel, mouth-bar and distal delta-front environments. From detailed thin-section work it is clear that these mudstone layers are not homogenous. Three facies are observed: unstratified mudstone (UM), some of which contain “floating” coarse grains, planar-laminated mudstone (PLM) and cross-laminated mudstone (CLM). Each facies represents deposition at differing suspended-sediment concentrations (SSC) (UM−high SSC, PLM−low-moderate SSC and CLM−low SSC). The thickest mudstone layers are always associated with underlying dune-scale cross-bedding, which has led to a proposed model where fluid mud can accumulate and is protected from the over-riding flow in the troughs of large dunes. This model is most relevant to tidal-fluvial channels where large dunes occur in the deepest water and in terminal distributary channels in mouth bars. The vertical stacking of facies within a single mudstone layer allows reconstruction of changes of the near-bed SSC values and current velocities that reflect deceleration and acceleration of the tidal currents over the tidal cycle or waning wave energy following a storm. Based on repeating patters termed “vertical successions” and “succession combinations,” individual tidal cycles can be observed within single mudstone layers and the relative strength of subordinate and dominant currents can be ii inferred. To aide in the understanding of how mud can accumulate over the complete range of SSCs, current velocities and grain sizes, a preliminary three-dimensional bedform phase diagram has been constructed for fine-grained sediment based on recent flumes studies. The phase diagram can be applied to mudrocks beyond the Tilje Formation. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2013-09-15 17:14:19.827

This study investigates Mio-Pliocene mass-transport deposits (MTDs) in an understudied, hydrocarbon-rich region of the northeastern Gulf of Mexico. The research utilizes a high-quality 3D seismic dataset with an area of 635 km2, along with wireline logs and biostratigraphic data. With the help of quantitative seismic geomorphology techniques, detailed mapping of MTDs suggests a complex erosional and depositional history. Deposition of a MTD unit resulted in a 180 m topographic high that substantially influenced the distribution and morphology of subsequent MTDs, specifically the bifurcation of later mass-transport flows. This bifurcation contributed to the generation of a non-shielded erosional remnant with an area of 65 km2. Depositional elements of the remnant strata are interpreted to be sediment waves. Instantaneous frequency attribute maps of the erosional remnant suggest a different lithology than the surrounding muddy MTDs; and, thus, the remnant unit is interpreted to be sandy. For the first time in literature, this research documented intra-MTD channel and lobe features. The development of a sinuous channel system encased within MTD gives new insights into mass-transport processes. This provides evidence for considering MTD as amalgamation deposits of multiple and different-type of flow events (e.g., turbidity currents and debris flows), rather than a singular event-deposit. The channel, lobe, and erosional remnant features examined in this research demonstrate reservoir-prone facies encased within MTD units, forming stratigraphic traps directly associated with mass-transport phenomena. This research contributes to the understanding of seal vs. reservoir rock development and distribution in the study area, as well as presents new developments into mass-transport deposit flow processes and their resulting morphologies.

Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or lithologies that experienced differential cementation. Hypothesized origins of these intercrater layered deposits include lacustrine, aeolian, volcanic airfall, and impact surge deposition. On Earth, rhythmically deposited strata can be examined in terms of stratal packaging, wherein the interplay of tectonics, sediment deposition, and change in base level results in predictable patterns with respect to changes in the amount of space available for sediment accumulation. Fundamental differences between tectonic regimes of Earth and Mars demand that packaging of layered strata primarily reflects changes in sediment influx and base level. Analysis of stratal packaging may therefore help us understand the relative roles of these parameters, and provide crucial constraint on martian depositional models. Rhythmic stratal patterns in Becquerel Crater (7°W 22°N) have been attributed to astronomical forcing of regional climate. A clear depositional model, however, has yet to be presented. Here, we reanalyze strata of Becquerel Crater and compare results with two additional crater successions. Results indicate that, by contrast with Becquerel Crater, strata within Danielson Crater (7°W 8°N) and an unnamed crater (Crater X; 1.2°W 9°N) do not record hierarchical packaging readily attributable to astronomical effects, and suggest that regional climate forcing may not be readily applied as a paradigm for all intracrater deposition. Similarities in depositional style in these three craters, however, may be linked by a model for sediment accumulation—with potential links to regional climate—wherein episodic melting of ground ice raised local base level, stabilized aeolian sedimentation, and resulted in differential cementation of accumulated strata.