Geo-Marine Letters

, Volume 29, Issue 6, pp 349–358 | Cite as

Subsurface control on seafloor erosional processes offshore of the Chandeleur Islands, Louisiana

  • David Twichell
  • Elizabeth Pendleton
  • Wayne Baldwin
  • James Flocks
Original

Abstract

The Chandeleur Islands lie on the eastern side of the modern Mississippi River delta plain, near the edge of the St. Bernard Delta complex. Since abandonment approximately 2,000 years b.p., this delta complex has undergone subsidence and ravinement as the shoreline has transgressed across it. High-resolution seismic-reflection, sidescan-sonar, and bathymetry data show that seafloor erosion is influenced by locally variable shallow stratigraphy. The data reveal two general populations of shallow erosional depressions, either linear or subcircular in shape. Linear depressions occur primarily where sandy distributary-channel deposits are exposed on the seafloor. The subcircular pits are concentrated in areas where delta-front deposits crop out, and occasional seismic blanking indicates that gas is present. The difference in erosional patterns suggests that delta-front and distributary-channel deposits respond uniquely to wave and current energy expended on the inner shelf, particularly during stormy periods. Linear depressions may be the result of the sandy distributary-channel deposits eroding more readily by waves and coastal currents than the surrounding delta-front deposits. Pits may develop as gas discharge or liquefaction occurs within fine-grained delta-front deposits, causing seafloor collapse. These detailed observations suggest that ravinement of this inner shelf surface may be ongoing, is controlled by the underlying stratigraphy, and has varied morphologic expression.

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References

  1. Baldwin WE, Pendleton EA, Twichell DC (2009) Geophysical data from offshore of the Chandeleur Islands, Eastern Mississippi Delta. US Geol Surv Open-File Rep 2008-1195Google Scholar
  2. Brooks GR, Kindinger JL, Penland S, Williams SJ, McBride RA (1995) East Louisiana continental shelf sediments: a product of delta reworking. J Coastal Res 11:1026–1036Google Scholar
  3. Cacchione DA, Drake DE, Grant WD, Tate GB (1984) Rippled scour depressions on the inner continental shelf off central California. J Sediment Petrol 54:1280–1291Google Scholar
  4. Coleman JM, Prior DB, Garrison LE (1978) Submarine landslides on the Mississippi River Delta. Offshore Technol Conf 10:1067–1071Google Scholar
  5. Divins DL, Metzger D (2008) NGDC Coastal Relief Model, vol 4. NOAA, http://www/ngdc.noaa.gov/mgg/coastal/coastal.html (accessed 20 January 2009)
  6. Duarte H, Menezes Pinheiro L, Curado Teixeira F, Monteiro JH (2007) High-resolution seismic imaging of gas accumulations and seepage in the sediments of the Ria de Aveiro barrier lagoon (Portugal). In: García-Gil S, Judd A (eds) Contrib 8th Int Conf Gas in Marine Sediments, September 2005, Vigo, Spain. Geo-Mar Lett SI 27(2/4):115–126. doi: 10.1007/s00367-007-0069-z CrossRefGoogle Scholar
  7. Ellis J, Stone GW (2006) Numerical simulation of net longshore sediment transport and granulometry of surficial sediments along Chandeleur Island, Louisiana, USA. Mar Geol 232:115–129CrossRefGoogle Scholar
  8. Flocks J, Twichell D, Sanford J, Pendleton E, Baldwin W (2009) Chapter 6. Sediment sampling analysis to define quality of sand resources. In: Baldwin W, Doran K, Flocks J, Guy K, Howd P, Lavoie D, Pendelton E, Sallenger A, Sanford J, Sullivan C, Twichell D, Williams J, Wright C, Bohling, C, Fearnley S, Georgiou I, Kulp M, Martinez L, Miner M, Penland S, Rogers B, Schindler J, Weathers D, Sand resources, regional geology, and coastal processes of the Chandeleur Island coastal system – an evaluation of the resilience of the Breton National Wildlife Refuge. US Geol Surv Open-File Rep (in press)Google Scholar
  9. Frazier D (1967) Recent deltaic deposits of the Mississippi River: their development and chronology. Trans Gulf Coast Assoc Geol Soc 17:287–315Google Scholar
  10. Garcia-Gil S, Vilas F, Garcia-Garcia A (2002) Shallow gas features in incised-valley fills (Ria de Vigo, NW Spain): a case study. Cont Shelf Res 22:2303–2315CrossRefGoogle Scholar
  11. Georgiou IY, Fitzgerald DM, Stone GW (2005) The impact of physical processes along the Louisiana Coast. J Coastal Res 44:72–89Google Scholar
  12. Goff JA, Mayer LA, Traykovski P, Buynevich I, Wilkens R, Raymond R, Glang G, Evans RL, Olson H, Jenkins C (2005) Detailed investigation of sorted bedforms, or “rippled scour depressions”, within the Martha’s Vineyard Coastal Observatory, Massachusetts. Cont Shelf Res 25:461–484CrossRefGoogle Scholar
  13. Hovland M, Judd AG (1988) Seabed pockmarks and seepages—impact on geology, biology and the marine environment. Graham & Trotman, LondonGoogle Scholar
  14. Kelley JT, Dickson SM, Belknap DF, Barnhardt WA, Henderson M (1994) Giant sea-bed pockmarks: evidence for gas escape from Belfast Bay, Maine. Geology 22:59–63CrossRefGoogle Scholar
  15. Majzlik EJ (2005) Modification and recovery of the shoreface of Matagorda Peninsula, Texas, following the landfall of Hurricane Claudette: the role of antecedent geology on short-term shoreface morphodynamics. Master’s Thesis, Texas A&M UniversityGoogle Scholar
  16. Missiaen T, Murphy S, Loncke L, Henriet J (2002) Very high-resolution seismic mapping of shallow gas in the Belgian coastal zone. Cont Shelf Res 22:2291–2301CrossRefGoogle Scholar
  17. Morang A, McMaster RL (1980) Nearshore bedform patterns along Rhode Island from side-scan sonar surveys. J Sediment Petrol 50:831–840Google Scholar
  18. Murray AB, Thieler ER (2004) A new hypothesis for the formation of large-scale inner-shelf sediment sorting and ‘rippled scour depressions’. Cont Shelf Res 24:295–315CrossRefGoogle Scholar
  19. National Data Buoy Center (2008) Historical data. http://www.ndbc.noaa.gov/ (accessed 20 January 2009)
  20. National Water Level Observation Network (2006) Tide Stations. NOAA/ National Ocean Service. http://tidesandcurrents.noaa.gov/nwlon.html (accessed 20 January 2009)
  21. Panagiotopoulos I, Voulgaris G, Collins MB (1997) The influence of clay on the threshold of movement of fine sandy beds. Coastal Eng 32:19–43CrossRefGoogle Scholar
  22. Penland S, Suter JR, Boyd R (1985) Barrier island arcs along abandoned Mississippi River deltas. Mar Geol 63:197–233CrossRefGoogle Scholar
  23. Penland S, Suter JR, Boyd R (1988) The transgressive depositional systems of the Mississippi River delta plain: a model for barrier shoreline and shelf sand development. J Sediment Petrol 58:932–949Google Scholar
  24. Roberts H (1980) Sediment characteristics of Mississippi River delta-front mudflow deposits. Trans Gulf Coast Assoc Geol Soc 30:485–496Google Scholar
  25. Roberts H (1997) Dynamic change of the Holocene Mississippi River delta plain: the delta cycle. J Coastal Res 13:605–627Google Scholar
  26. Suter JR, Penland S, Williams SJ, Kindinger JL (1988) Transgressive evolution of the Chandeleur Islands, Louisiana. Trans Gulf Coast Assoc Geol Soc 38:315–322Google Scholar
  27. Thieler ER, Pilkey OH, Cleary WJ, Schwab WC (2001) Modern sedimentation on the shoreface and inner continental shelf at Wrightsville Beach, North Carolina, USA. J Sediment Res 71:958–970CrossRefGoogle Scholar
  28. Walsh JP, Corbett DR, Mallinson D, Goni M, Dail M, Loewy C, Marciniak K, Ryan K, Smith C, Stevens A, Sumners B, Tesi T (2006) Mississippi Delta mudflow activity and 2005 Gulf hurricanes. EOS Trans AGU 87:477–478CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • David Twichell
    • 1
  • Elizabeth Pendleton
    • 1
  • Wayne Baldwin
    • 1
  • James Flocks
    • 2
  1. 1.U.S. Geological SurveyWoods HoleUSA
  2. 2.U.S. Geological SurveyFlorida Integrated Science CenterSt. PetersburgUSA

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