Near-surface stratigraphy and morphology, Mississippi Inner Shelf, northern Gulf of Mexico

Flocks, James G.; Kindinger, Jack L.; Kelso, Kyle W.; Bernier, Julie C.; DeWitt, Nancy T.; FitzHarris, Michael

doi:10.3133/ofr20151014

Cited by 2 publications

(1 citation statement)

References 7 publications

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“…Both are critical to improve our understanding of coastal geomorphic thresholds moving forward, given that current 4 relative sea level rise rates have exceeded rates during island formation (Otvos 2018) and the likely future increase in storm frequency and intensity (Emanuel 2005). This study aims to holistically synthesize many previous works in the area , Flocks et al 2014, Twichell et al 2011, Kramer 1990, Hummel and Parker 1995, Hummel and Smith 1996, Otvos 1979, 1981, 1985, 1986, 2018 supplemented with newly acquired geophysical and chronologic data to investigate the coevolution of the barrier islands and other coastal systems, highlighting sand supply through ravinement of the inner shelf.…”

Section: Shorelines Of the Gulf Of Mexico Are Among The Most Vulnerabmentioning

confidence: 99%

Late Quaternary evolution and stratigraphic framework influence on coastal systems along the north-central Gulf of Mexico, USA

Hollis

Wallace

Miner

et al. 2019

Quaternary Science Reviews

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Coastal systems in the Gulf of Mexico are threatened to reduced sediment supply, storm impacts and relative sea level rise (RSLR). The geologic record can provide insights of geomorphic threshold crossings (formation, progradation, transgression, destruction) to these forcing mechanisms to predict future barrier evolution to climate change. The stratigraphic framework and antecedent topography directly influence coastal evolution over geologic timescales. This study synthesizes ~2100km of geophysical data, 700+ sediment cores, and 63 radiocarbon dates to regionally map two sequence boundaries, multiple ravinement surfaces and fourteen depositional facies. One marine isotope stage (MIS) 6 valley's fill provided up to 300 x10 6 m 3 of sand to modern systems through transgressive ravinement during the Holocene. Repeated storm breaches or tidal inlets correspond to paleotopographic low's in the MIS 2 surface. A Holocene geomorphic evolutionary model was created for Petit Bois and Dauphin Island from available data, highlighting RSLR rates and sediment supply. As the MIS 2 surface was flooded, tidal/wave scour supplied sand to migrating marine shoals. These rapidly transgressing shoals converted drowned paleovalleys to estuaries starting about 9ka. Islands formed in their modern positions about 6ka, when sediment supply was high and RSLR rates were 2mm/yr. Between 4ka-1750 CE. Islands prograded due to RSLR rates of 1-0.4mm/yr and sufficient sand supply from alongshore and inner shelf sources. Currently, the islands experience RSLR rates of 3.61 mm/yr and reduced sediment supply resulting in barrier degradation. This study provides geologic evidence of coastal geomorphic thresholds related to RSLR, sediment supply and antecedent topography. iii ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Davin Wallace for his guidance and great support through this project. I would also like to thank my committee members Dr. Michael Miner and Dr. Jessica Pilarczyk, and lab mates, Clayton Dike, Nina Gal, and Shara Gremillion for their helpful and insightful feedback and guidance. This project was funded by the Bureau of Ocean and Energy Management, as part of a Gulf of Mexico sand resource mapping effort. Thank you to colleagues at the University of Alabama, the Geological Survey of Alabama and USGS for allowing core sampling. The USGS and UTIG shared archive geophysical data. Mollusk bivalve identification was greatly aided by Dr. Jennifer Walker. Dr. John Anderson (Rice) and Dr. Ervin Otvos (USM) also provided valuable insight. iv DEDICATION This thesis is dedicated to friends, family and loved ones especially Bob, Ellen, Joey and Alli. Their love, appreciation and support allowed me to pursue my scientific passion. v

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Section: Shorelines Of the Gulf Of Mexico Are Among The Most Vulnerabmentioning

confidence: 99%

Late Quaternary evolution and stratigraphic framework influence on coastal systems along the north-central Gulf of Mexico, USA

Hollis

Wallace

Miner

et al. 2019

Quaternary Science Reviews

Self Cite

View full text Add to dashboard Cite

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Evaluating oil and gas industry two-dimensional multichannel seismic data for use in near-surface assessment of geologic framework and potential marine minerals resources

Flocks,

Forde,

Bosse

2023

Techniques and Methods

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Marine seismic reflection data acquired across the Gulf of Mexico during oil and gas exploration are available to the public through an online database archive. The data are archived as two-dimensional multichannel seismic data in two digital formats. The formats include image files in portable document format (PDF), and binary files in industry standard Society for Exploration Geophysicists revision Y (SEG-Y) format. Also included in the database are navigation files and acquisition information associated with the collection of the data.This study examines the data acquired within two geographic areas in the northern Gulf of Mexico. Although the seismic reflection data are acquired for oil and gas exploration many kilometers below the seafloor, this study focuses on the feasibility of using the data for near-surface geologic and seafloor morphologic studies (<100 meters below the seafloor). The report outlines the methodologies used to recover and process the data, including computer processing steps to convert the PDF imagery into SEG-Y format. The report includes twodimensional profiles of the data to demonstrate the efficacy of the data in near-surface geologic studies. The study found that, for the two areas of interest, the seafloor reflectors in most of the available data are not resolvable. Although the data are readily available and computer processing can adequately image the uppermost reflectors of the seismic profiles, the resolution of the data in most cases are not suitable for nearsurface geologic evaluations.

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Near-surface stratigraphy and morphology, Mississippi Inner Shelf, northern Gulf of Mexico

Cited by 2 publications

References 7 publications

Late Quaternary evolution and stratigraphic framework influence on coastal systems along the north-central Gulf of Mexico, USA

Late Quaternary evolution and stratigraphic framework influence on coastal systems along the north-central Gulf of Mexico, USA

Evaluating oil and gas industry two-dimensional multichannel seismic data for use in near-surface assessment of geologic framework and potential marine minerals resources

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