 Subtask: Geologic Framework and Holocene Coastal Evolution – Mississippi-Alabama Region
Subtask Leader: James Flocks - USGS St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida
Aim
Coastal features evolve along the northern Gulf of Mexico (NGOM) coast as shallow (<100 meter) stratigraphy and topography interact with modern processes such as sea-level and sediment supply changes and climatic variability. By characterizing the geologic framework and surface characteristics of the coastal area, we can understand the variable response of the NGOM coast to natural and human-related mechanisms.
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Satellite image of the Gulf Coast region along the Mississippi and Alabama coast after landfall of Hurricane Katrina. The image is enhanced to show coastal flooding (dark colors). The barrier islands sustained significant erosion during the storm.
The Chandeleur Island chain in the center of the image was severely eroded by the storm and is barely visible. Knowledge of the geologic framework in this region helps scientists understand how the shorelines will respond to future impacts from storms like Hurricane Katrina. Image taken September 15, 2006 by NASA's Terra satellite.
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The geomorphology of the northern Gulf of Mexico (NGOM) coastal zone is a complex arrangement of landscapes produced by fluvial processes and sea level rise over the past 7000 years.
This subtask addresses the inner shelf offshore of the Mississippi and Alabama coastline, to develop a geologic framework for the region through the synthesis of existing knowledge and integration with new research. The goal is to provide a comprehensive understanding of the geology and its role in the coastal evolution of the region.
Approach
The goal of this subtask is to map the seafloor and late Holocene stratigraphy of the inner shelf and coastal region offshore of Mississippi and Alabama.
Interpretation of the seafloor and subbottom geophysical data will provide a high-resolution acoustic response map of platform stratigraphy. Direct sampling (coring) is necessary to validate the acoustic features identified in the geophysical data, which is then used to determine the regional framework. This information will be integrated with similar investigations around the Chandeleur Islands, La (Subtask 2.1) to compare and contrast the processes controlling the two island systems. Information from the investigation will also contribute to Task 3 (Evolution of Northern Gulf Coast Barrier Islands) to provide seafloor change assessments.
The specific objectives are to:
- Characterize the geologic framework underlying Mississippi Sound and offshore of the Gulf Coast islands; and
- Improve our understanding of the platform on which these islands are built.
- Provide an up to date characterization of the bathymetry around the Mississippi Barrier Islands.
Accomplishments
- Geophysical surveys of the seafloor and subbottom have been completed for the Gulf Islands National Seashore from Cat Island to Dauphin Island.
- Processing of data collected in 2008 is complete and interpretation of the data are underway. Processing of data collected in 2009 is underway.
Publications
Manuscripts
Osterman, L.E., Poore, R.Z., Swarzenski, P.W., Senn, D., DiMarco, S., and Turner, R.E., 2009, The 20th century development and expansion of Louisiana shelf hypoxia, Gulf of Mexico: Geo-Marine Letters, v. 29, no. 6, p. 405-414. Flocks, J., Ferina, N., and Kindinger, J., , Summary of knowledge regarding the recent geologic framework and geomorphology of the Mississippi-Alabama shelf, northern Gulf of Mexico, in, Holmes, C. W. and Buster, N.A. (Eds) Gulf of Mexico-Origins, Waters, and Biota: Geology. Texas A&M University Press, College Station, Texas
Open File Report(OFR)
Flocks, J.G., and Swarzenski, P.W., 2007, Cruise report: Sediment collection from Orca and Pigmy Basins, Gulf of Mexico, and analyses for texture and trace-metal concentrations, July 2002, PAGE 127 campaign; chapter 13, in Winters, W.J., Lorenson, T.D., and Paull, C.K., eds., Initial report of the IMAGES VIII/PAGE 127 gas hydrate and paleoclimate cruise on the RV Marion Dufresne in the Gulf of Mexico, 2-18 July 2002; Open-File Report 2004-1358: Woods Hole, MA, U.S. Geological Survey, p. 13-11 - 13-32. Data Series
Dreher, C., Flocks, J.G., Ferina, N., and Kulp, M.A., 2008, Archive of sediment-vibracore data collected from Sandy Point to Belle Pass, Louisiana, 1983 through 2001 (surveys: 00SCC00, 83CR00, and 86P00): U.S. Geological Survey Data Series 344. DeWitt, N.T., Flocks, J., Hansen, M., Kulp, M., and Reynolds, B.J., 2007, Bathymetric survey of the nearshore from Belle Pass to Caminada Pass, Louisiana: methods and data report: U.S. Geological Survey Data Series 312 [CD-ROM]. Abstracts and Presentations
DeWitt, N.T., Flocks, J.G., and Reynolds, B.J., 2008, High-resolution single-beam bathymetry of Camille Cut, Ship Island, Gulf Islands National Seashore, Mississippi: Assessing short-term bathymetric change, in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 13 and 104. Dreher, C., and Flocks, J., 2008, Comparison of foraminiferal biofacies in modern deltaic environments; proxies for coastal change [abstract], in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 105. Flocks, J., Lavoie, D., Twichell, D.C., and Miner, M.D., 2008, Assessing the stability and fate of our barrier islands, Northern Gulf of Mexico [abstract and poster], in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 49. Flocks, J., Twichell, D.C., Baldwin, W.E., Kulp, M., and Miner, M.D., 2008, Influence of antecedent geology on barrier island development, northern Chandeleur Islands, Louisiana [abstract #2462], in 2008 Ocean Sciences meeting, March 2-7, 2008, Orlando, FL, American Society of Limnology and Oceanography. Flocks, J., Twichell, D.C., Baldwin, W.E., Pendleton, E.A., Miner, M.D., and Kulp, M., 2008, Shallow stratigraphic framework and evolution of the northern Chandeleur Islands, Louisiana [abstract], in Association of Environmental and Engineering Geologists 2008 annual meeting program with abstracts, New Orleans, LA, p. 63-64.
Flocks, J., Williams, S.J., Kindinger, J.L., and Kulp, M., 2008, Understanding the shallow stratigraphic architecture of the Northern Gulf of Mexico: the key to identifying potential resources for shoreline stabilization [abstract and poster], in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 48. Dadisman, S.V., Flocks, J., Williams, S.J., Reid, J., Calderon, K., and Paskevich, V., 2007, LASED and usSEABED data management and analysis tools to assist mapping coastal change of the Gulf Coast [abs]: NOAA Coastal Services Center, Coastal GeoTools Conference, Myrtle Beach, SC, 2007 [Proceedings], p. 59
Dadisman, S.V., Flocks, J.G., and Dwyer, B., 2007, LASED: A data-management scheme for geologic and geophysical data collected from the Louisiana coastal zone [abstract 78-13]: Geological Society of America, Abstracts with Programs, v. 39, no. 6, p. 211. Flocks, J., 2007, Subdelta depositional processes: high-resolution characterization of the Mississippi River Delta plain [presentation], in Proceedings, International Delta Roundtable, Lafayette, LA, November 28-30, 2007, U.S. Geological Survey National Wetlands Research Center (NWRC). |
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