Start |Author Index | View Uploaded Presentations | Meeting Information

South-Central Section - 50th Annual Meeting - 2016

Paper No. 7-8
Presentation Time: 8:00 AM-5:30 PM

DELTAIC EVOLUTION RECORDS AND STRATIGRAPHY STRUCTURES IN LOWER BRETON SOUND, MISSISSIPPI DELTA LOBE


WANG, Jiaze, Department of Oceanography and Coastal Science, Louisiana State University, 2151 Energy, Coast and Environment Building, Baton Rouge, LA 70803, XU, Kehui, Department of Oceanography and Coastal Sciences, Louisiana State University, 2165 Energy, Coast and Environment Building, BATON ROUGE, LA 70803; Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803, BENTLEY, Samuel J., Department of Geology & Geophysics, Louisiana State University, Baton Rouge, LA 70803; Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803, CHEN, Qin, Coastal Studies Institute, Louisiana State University, E235 Howe-Russell Geoscience Complex, Baton Rouge, LA 70803; Department of Civil and Environmental Engineering, Louisiana State University, BATON ROUGE, LA 70803, WHITE, Crawford, Department of Geology & Geophysics, Louisiana State University, Baton Rouge, LA 70803, MALONEY, Jillian, Department of Geological Sciences, San Diego State University, San Diego, CA 92182 and OBELCZ, Jeff, Department of Oceanography and Coastal Sciences, Louisiana State University, 2151 Energy, Coast and Environment Building, BATON ROUGE, LA 70803, jwang72@lsu.edu

The Mississippi River has developed six major lobes in its deltaic plain since the start of the Holocene. The modern lobe is the birdfoot Balize delta. When the Mississippi River switched its channel to input sediment in the Breton Sound receiving basin, St. Bernard (2800-1000 yr B.P.) and Plaquemine (750-500 yr B.P.) delta lobes were developed in the Breton Sound area. However, the Lower Breton Sound area is mostly under the present sea level due to subsidence, sea level rise and limited sediment supply. We have collected some geophysical data, including side-scan and sub-bottom data, and 25 sediment cores in the Lower Breton Sound area to study the stratigraphy structures and delta evolution recorded in Lower Breton Sound. Based on side-scan and sub-bottom data in this area, a two-layer structure has apparently developed in Lower Breton Sound. LOI (loss on ignition) and grain size results of 25 sediment cores show that relatively high organic matter content and fine sediment (clay or silt-clay) are present in the upper 1.5 m, which is corroborated by the geophysical data. The lower 2.5-3.5 m thickness sediments in those 25 cores are mainly interbedded sand-silt-clay layers, with several overbank clay layers in some cores. In addition, a 0.4 m-thick peat layer is present at about 1 m depth below sediment surface. Based on our analysis, it was found that stratigraphy under about 1.5 m depth was probably the delta plain faces formed during the delta lobe formation. The upper 1.5 m thickness sediment layer was the wetland sub-faces, which was possibly developed in the delta plain since the delta lobe was abandoned and relative sea level became rising faster than before. Further AMS C-14 dating work will be done to help better interpret the stratigraphic structure and delta evolution in this sediment receiving basin.

Session No. 7--Booth# 38

T9. Coastal and Shelf Sediment Transport Processes and Products of the Northern Gulf of Mexico (Posters)
Monday, 21 March 2016: 8:00 AM-5:30 PM
Riverview B (Hilton Baton Rouge Capitol Center)
Geological Society of America Abstracts with Programs. Vol. 48, No. 1
doi: 10.1130/abs/2016SC-273420
© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
Back to: T9. Coastal and Shelf Sediment Transport Processes and Products of the Northern Gulf of Mexico (Posters)
<< Previous Abstract | Next Abstract >>