<p> Late Jurassic through Early Cretaceous strata of the Gannett Group record initial development of the Sevier thrust belt and adjacent foreland basin. Concepts of nonmarine sequence stratigraphy were used to determine the depositional and base level history of the Gannett Group in southeastern Idaho and western Wyoming. Base level fluctuations were driven entirely by tectonic processes, while tectonic uplift in the source area was a major control on sequence development. Six measured sections were revisited or measured and correlated using the concepts of sequence stratigraphy. Four distinct sequences were identified and correlated. Each sequence can be divided into degradational, transitional, or aggradational systems tracts. Where the degradational systems tracts are preserved, they are represented by thin conglomerates. Transitional systems tracts overly the degradational systems tracts and consist of thick sections of laterally discontinuous sandstone and fluvial overbank muds, which grade laterally into continuous limestone and calcareous mudstones that comprise the aggradational systems tract.</p>

<p> Cretaceous Period. There is limited research on organic carbon content of the Pierre Shale in South Dakota. Frequent volcanic eruptions combined with climate change resulted in an increase in carbon dioxide in the atmosphere, leading to decreases in marine oxygen content. Decreasing marine oxygen has been attributed to higher amounts of preserved organic matter in marine sediment. Impact of volcanic ash deposition in the Cretaceous Interior Seaway has not been thoroughly studied. The Pierre Shale also contains the Crow Creek Member, a 5 foot thick layer of unconsolidated sand and rip-up clasts which may indicate a high-energy depositional event. Some hypothesize that it was deposited by a tsunami generated by the Manson impact. Others believe the Crow Creek Member is evidence of a marine low-stand that occurred before the Bearpaw Cyclothem. It is possible that the depositional event that deposited the Crow Creek Member may have led to increases in organic carbon preservation depending on the burial rates and amount of organic carbon preserved. </p><p> To investigate the connection between volcanic ash deposition, the Crow Creek Member deposition, and organic matter preservation of the coastal Cretaceous Interior Seaway, stable isotope geochemistry, trace element geochemistry, and total organic carbon analyses were performed on a 500 foot core drilled near Fort Pierre, South Dakota. Ash beds were identified using X-ray diffraction analysis. Core sampling was driven by location of the Crow Creek Member (above below and within one foot) and by location of ash beds (above below and within one inch), but samples were also taken based on highest and lowest gamma ray values for each five foot (1.52m) core segment. Core sampling was restricted because every other five foot (1.52 meter) section of the Treedam core segement was available for sampling. Statistical T-tests and Z-tests were performed on sample data to determine if there was a significant difference in geochemical signatures between core deposited before and after ash bed deposition and Crow Creek Member deposition. Results and T and Z statistical analyses show no significant changes in stable isotopes nor trace elements as a result of ash bed deposition nor the Crow Creek Member depositional event. Results also indicate that variability of the coastal brackish marine system made any significant trends harder to isolate on such a small scale. Overall &delta;¹³C_org signatures ( -27 to -26 &permil;) indicate that the Cretaceous Interior Seaway was deposited in a brackish shallow marine environment and that there were no drastic changes in sea level throughout the deposition of the Pierre Shale Group that was sampled (Gregory Member up through Virgin Creek Member). The &delta;<p style="font-variant: small-caps">15</p>N data range (-6 to +1 &permil;) show that fixed nitrogen was scarce during the deposition of the Pierre Shale and that most of the available marine nitrogen was likely fixed by cyanobacteria.</p>

<p> A 6012-foot Monterey Formation succession at Chico Martinez Creek, San Joaquin basin, is characterized at high spatial resolution by spectral gamma-ray data in 2- foot increments, 5-foot lithologic descriptions, and qualitative XRD and FTIR analysis. Based on these data, the 4 Monterey members&ndash;the Gould, Devilwater, McDonald and Antelope shales&ndash;are subdivided into 7 distinctive lithofacies. New paleomagnetic data, combined with industry-provided biostratigraphy establishes a chronostratigraphic framework and allows determination of linear sediment accumulation rates. Condensed sedimentation at the onset of McDonald deposition (~14 Ma) is also observed in correlative members in the Pismo, Santa Maria and Santa Barbara basins. This regional event is associated with eustatic regression from the Mid-Miocene highstand related to formation of the East Antarctic Ice Sheet and ongoing thermotectonic basin subsidence. A surge in linear sediment accumulation rates in the siliceous upper McDonald and Antelope (~10.4 Ma) is attributed to a regional increase in diatom productivity. </p>

<p>Calcium bentonite deposits of the Glendon and Bucatunna formations of the Oligocene Vicksburg Group located in Smith County, Mississippi were examined to determine the depositional environment, diagenetic history and origin of the bentonite. Traditionally, calcium bentonite was considered to be the product of the weathering of volcanic ash deposits. The hypothesis tested is that the bentonite deposits are not a result of weathered volcanic ash, but are a result of weathered marl. Core samples were drilled from the Chisholm bentonite mine in Smith County and were studied using X-ray diffraction, scanning electron microscopy, and petrographic microscopy. Abundant bacteria along with nanometer-scale organic textures were found throughout and are consistently associated with bentonite, illite, and smectite. No evidence of volcanic ash was found. It appears that the calcium bentonite clays in the Glendon and Bucatunna formations of Smith County, Mississippi formed from weathering, including bacterial activity, of glauconite-bearing marl.

<p> The Waucobi Lake Beds in Owens Valley, California contain two distinct facies representing saline-alkaline and fresh water environments. The potential cause for the change in lacustrine facies is examined through geomorphic, geochemical and sedimentological analyses. An age range for the lake beds was constrained with the dating and &ldquo;fingerprinting&rdquo; of 13 tuffs throughout the Waucobi Lake Bed exposures. 40Ar/39Ar dating completed for this study provides ages of 2.63 to 2.06 Ma for tuff layers found within the lake beds, with the transition from saline-alkaline facies to fresh water facies occurring around 2.5-2.4 Ma. Regional climate during the late Pliocene-early Pleistocene is reflected by the saline-alkaline environment within Waucobi. However, the Waucobi environment deviates from regional climate after 2.5 Ma, implying that the fresh water facies represents a change in lacustrine hydrology. Given the coincidence between a prominent seismite recorded in the lake beds with the facies change, tectonic activity rather than climate is postulated as the cause for the transition in the lake environment.</p>

<p> A study of 230 samples of porcelanite and siliceous mudstone from a single stratigraphic section containing all three silica phases in the Sisquoc and Monterey formations, Casmalia Hills, California, tested established models of silica diagenesis. Analysis of composition, silica phase, and d₁₀₁-spacing using combined EDS/XRF and XRD documented a broad distribution of opal-CT d₁₀₁-spacing values rather than a linear progression for any particular compositional range predicted by prior studies. The data from this thesis study strongly suggest that other variables (e.g., carbonate, organic matter) besides burial depth/temperature and normalized silica:detritus ratios are critical to diagenetic ordering and that the opal-CT d₁₀₁-spacing and silica content of a single sample cannot be used as a geothermometer. Instead, the maximum opal-CT d₁₀₁-spacing in a set of samples for any normalized silica:detritus ratio in a stratigraphic interval may be useful to determine the minimum temperature or maximum burial depth reached prior to tectonic uplift.</p>

<p> Submarine-fan deposits form the largest sediment accumulations on Earth and host significant reservoirs for hydrocarbons. While many studies of ancient fan deposits qualitatively describe lateral architectural variability (e.g., axis-to-fringe, proximal-to-distal), these relationships are rarely quantified. In order to enable comparison of key relationships that control the lateral architecture of submarine depositional environments, I digitized published bed-scale outcrop correlation panels from five different environments (channel, levee, lobe, channel-lobe-transition-zone, basin plain). Measured architectural parameters (bed thickness, bed thinning rates, lateral correlation distance, net-to-gross) provide a quantitative framework to compare facies architecture between environments. The results show that sandstone and/or mudstone bed thickness alone or net-to-gross do not reliably differentiate between environments. However, environments are distinguishable using a combination of thinning rate, bed thickness, and correlation distance. For example, channel deposits generally display thicker sandstone beds than mudstone beds whereas levees display the opposite trend. Lobe deposits display the most variability in all parameters, and thus would be the most difficult to identify in the subsurface. I sub-classified lobe deposits to provide a more detailed analysis into unconfined, semiconfined and confined settings. However, the results for semiconfined lobes indicate that the degree of lobe confinement and subenvironment is not easily interpretable at the outcrop scale. This uncertainty could be partially caused by subjectivity of qualitative interpretations of environment, which demonstrates the need for more quantitative studies of bed-scale heterogeneity. These results can be used to constrain forward stratigraphic models and reservoir models of submarine lobe deposits as well as other submarine depositional environments. </p><p> This work is paired with a case study to refine the depositional environment of submarine lobe strata of the Upper Cretaceous Point Loma Formation at Cabrillo National Monument near San Diego, California. These fine-grained turbidites have been interpreted as distal submarine lobe deposits. The strike-oriented, laterally-extensive exposure offers a rare opportunity to observe bed-scale architecture and facies changes in turbidites over 1 km lateral distance. Beds show subtle compensation, likely related to evolving seafloor topography, while lobe elements show drastic compensation. This indicates more hierarchical method of compensational stacking as the degree of bed compensation is small compared to the degree of element compensation. Thinning rates and bed thicknesses are not statistically different between lobe elements. This signifies that the lateral exposure is necessary to distinguish lobe elements and it would be extremely difficult to accurately interpret elements in the subsurface using 1D data (e.g., core). The grain size, mudstone to sandstone bed thicknesses, element/bed compensation, and lack of erosion observed in the Cabrillo National Monument exposures of the Point Loma Formation are most similar to values of semiconfined lobe deposits; hence, I reinterpret that these exposures occupy a more medial position, perhaps with some degree of confinement.</p><p>

<p>The Cretaceous-Paleogene Boundary Deposit is an impact-induced sedimentary deposit across the Gulf of Mexico basin, deposited due to the catastrophic effects of the Chicxulub Impact. The purpose of this project was to determine what the lithology and sedimentology evidence found in the Justiss Louisiana Central IPNH No. 2 well core from LaSalle Parish, Louisiana, tells us about the depositional history of the end-Cretaceous deposit and how the formation of this deposit was influenced by the effects of the Chicxulub Impact over 1000 km to the south. Project objectives were to characterize the end-Cretaceous sediments found in LaSalle Parish, Louisiana, to determine their depositional history as it relates to the Chicxulub Impact in Yucatan, Mexico, and to relate these onshore sediments to the basin-wide Cretaceous-Paleogene Boundary Deposit. A full description of the core was made and 35 thin sections from throughout the core were created and analyzed. Sedimentology evidence suggests that the end-Cretaceous chalk was deposited by seismically-induced mass wasting and later tsunami activity as a direct result of the Chicxulub Impact, and that the previously-proposed thickness of the Cretaceous-Paleogene Boundary Deposit may be overestimated.

Lake Tuborg is a large lake on west-central Ellesmere Island, Nunavut. Part of the lake is meromictic, and contains trapped saltwater below about 55 m depth. The lake receives meltwater and sediments from multiple sources, including snowmelt and glacier melt. A lake process study was undertaken from 2001-2003 at Lake Tuborg that involved obtaining profiles of water temperature, salinity, transmissivity, and dissolved oxygen. Networks of short and long sediment cores were also obtained throughout the lake. During the last year of monitoring the lake and its sediments, a large catastrophic drainage of an ice-dammed lake occurred (a jökulhlaup). This was the largest jökulhlaup witnessed in Canada since 1947. Detailed measurements of lake conditions before, during, and after the jökulhlaup allowed the responses to be measured in great detail. The lake drained by floating its ice dam, an extremely rare drainage style in the Canadian High Arctic. The basin of Lake Tuborg closest to jökulhlaup inflow filled with fresh, cold and turbid water. A sill separates this basin from the larger more distal meromictic basin, and this sill effectively blocked turbidity currents from entering this basin. Conclusions from this phase of research include (1) salinity and temperature in the saltwater basin were minimally affected by the jökulhlaup, and (2) at a deep, distal location, an identifiable thick, coarse-grained, non-erosive deposit was produced by the jökulhlaup. The above conclusions allowed the varved sedimentary record to be examined for similar deposits in the past, with the assumption that similar deposits could be found in the long core record, the sediments could be dated, and that previous jökulhlaup deposits would also be nonerosive. Varve-thickness counting, Cesium-137 dating, and particle size analyses showed that prior to 1960, no similar events occurred in roughly the last thousand years. In addition, only three large jökulhlaups have occurred in the last thousand years, all of which occurred after about 1960. This significantly improves the understanding of the history of the lake, the surrounding glaciers, and the paleoclimate of the region. The lake bottom deposits that were sampled before, during and after the 2003 jökulhlaup were extraordinarily unique. A major part of the work of characterizing these deposits involved determining the size of their constituent particles. Image analysis of sedimentary particles using backscattered electron microscope imagery is a method to determine particle size at extremely high resolution. This tool improves on existing techniques since it automates the process of statistically processing images, quantifies the percentage of disturbances on images, and allows for extremely small measurement windows relative to particle size by implementing special particle counting rules.

<p> The United States Bureau of Ocean Energy Management (BOEM)&rsquo;s Sandy Needs Assessment collected geophysical and geotechnical data, related to beach nourishment activities, along the continental shelf south of Long Island between 2015&ndash;2017 in an area offshore the Fire Island National Sea Shore, near Watch Hill, NY. This new geological and geophysical data provides evidence of continuous and ongoing sand transport offshore of Fire Island National Sea Shore. New stratigraphic evidence shows the evolution, migration and erosion of shore-oblique sand ridges formed from the reworking of glacial outwash sand consistent with a conceptual process model. Three separate ridge features are related to each other with evidence of direct ridge migration in the region. Outwash fans and deltas likely provided the cores of mesoscale submarine ridges n the study area. Subsequent episodes of ridge erosion remobilized sand to feed the growth of ridges further west. The possibility of natural transport process actively delivering sand to the shore remains, but is not identified, and will require further work before these ridges can be sustainably utilized in nourishment activities.</p><p>