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Framework and Evolution of a Transgressed Delta Lobe: the St University of New Orleans ScholarWorks@UNO University of New Orleans Theses and Dissertations Dissertations and Theses 5-15-2009 Framework and Evolution of a Transgressed Delta Lobe: The St. Bernard Shoals, Gulf of Mexico Bryan E. Rogers University of New Orleans Follow this and additional works at: https://scholarworks.uno.edu/td Recommended Citation Rogers, Bryan E., "Framework and Evolution of a Transgressed Delta Lobe: The St. Bernard Shoals, Gulf of Mexico" (2009). University of New Orleans Theses and Dissertations. 968. https://scholarworks.uno.edu/td/968 This Thesis is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights- holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Thesis has been accepted for inclusion in University of New Orleans Theses and Dissertations by an authorized administrator of ScholarWorks@UNO. For more information, please contact [email protected]. Framework and Evolution of a Transgressed Delta Lobe: The St. Bernard Shoals, Gulf of Mexico A Thesis Submitted to the Graduate Faculty of the University of New Orleans in partial fulfillment of the requirements for the degree of Master of Science in Earth and Environmental Sciences Coastal Geology by Bryan E. Rogers B.S. University of New Orleans, 2006 May 2009 Dedication I dedicate this master’s thesis to the late Dr. Shea Penland for his tireless efforts focused on Louisiana coastal issues, geologic education, and his personal assistance on this project as well as his teachings. ii Acknowledgments First and foremost I thank my advisor, Dr. Mark Kulp, without whom this project could never have happened, for helping to develop a project in my area of interest, and for his continual encouragement and advice. I would also like to express thanks to Dr. Dawn Lavoie and Dr. Mike Miner both of whom provided much needed guidance. I would also like to extend my gratitude to Jeff Motti, Dane Fischer and the crew of the R/V Acadiana. I also thank all my friends and fellow geologists at UNO. Of course, I am thankful for the help and support of my family and especially my wife, Tiffany. iii Table of Contents List of Figures......................................................................................................................v List of Tables ..................................................................................................................... vi Abstract............................................................................................................................. vii Introduction..........................................................................................................................1 Rational............................................................................................................................6 Study Area ..................................................................................................................6 Regional Geologic Background.......................................................................................7 Quaternary Sea-Level for the Northern Gulf of Mexico .................................................8 Holocene Evolution of the Eastern Louisiana Shelf......................................................10 Chronology of the St. Bernard Delta Complex.........................................................12 St. Bernard Shoals..........................................................................................................17 Previous Studies of the Eastern Louisiana Shelf and the St. Bernard Shoal ............17 St. Bernard Shoal Morphology .................................................................................19 Methods..............................................................................................................................25 Approach of this Study ..................................................................................................25 CI-87 Seismic Lines.......................................................................................................26 CI-87 Vibracore .............................................................................................................29 SBS-08 Seismic Data.....................................................................................................37 SBS-08 Side Scan Imagery............................................................................................37 SBS-08 Sediment Samples ............................................................................................37 Navigation......................................................................................................................40 SBS-08 Dataset Methodology........................................................................................40 Results................................................................................................................................42 Interpretations and Major Stratal Boundaries................................................................42 Progradational Facies................................................................................................44 Transgressive Facies .................................................................................................51 Regional Stratigraphic Relationships.............................................................................53 St. Bernard Delta Maps..................................................................................................58 2008 Side Scan Images ..................................................................................................62 Discussion..........................................................................................................................67 Distributary Advancement Across the Eastern Louisiana Shelf...................................67 La Loutre Progradation and Beach Ridge Construction..........................................68 Transgression of the St. Bernard Bathymetric High.....................................................72 Marine Forces Driving the St Bernard Shoals Evolution .............................................73 Model of Shelf Development........................................................................................79 Conclusions........................................................................................................................83 Future Work..................................................................................................................84 References..........................................................................................................................86 Vita.....................................................................................................................................94 iv List of Figures Distribution of Holocene age sand shoals in Louisiana ......................................................3 Study area.............................................................................................................................4 Transgressive Submergence model......................................................................................5 Eustatic sea-level curves......................................................................................................9 Isopach map and structural contour map of the topstratum lithosome ..............................11 Modified Mississippi River delta chronology map............................................................13 Holocene chronology of the Mississippi River delta.........................................................14 Deltaic progradational facies model ..................................................................................15 Proposed chronologies for the St. Bernard delta complex delta lobes ..............................16 1778 British Naval Survey Map of the Louisiana Coast ...................................................18 St. Bernard Shoals isopach map.........................................................................................20 USGS 1:250,000 scale Breton Sound map ........................................................................21 Modified isopach map of the St. Bernard Shoals ..............................................................23 Map showing location of cross sections A-A’ and B-B’ with vibracores .........................27 Map of CI-87 sesimic tracklines and vibracore locations..................................................28 CI-87 vibracore log symbology .........................................................................................31 Vibracore logs for CI-22 to CI-30 .....................................................................................32 Vibracore Logs for CI-31 to CI-46 ....................................................................................33 Vibracore Logs for CI-11 to CI-52 ....................................................................................34 Vibracore logs for CI-31 to CI-34 .....................................................................................35 Map of SBS-08 seismic tracklines.....................................................................................38
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