Advertisement

Carbonates and Evaporites

, Volume 19, Issue 1, pp 75–85 | Cite as

Sedimentation and porosity enhancement in a breached flank margin cave

  • Lee J. Florea
  • John E. Mylroie
  • Adam Price
Article

Abstract

San Salvdor Island, Bahamas, provides unique opportunities to study modern geologic processes on carbonate platforms as a result of constraints in time and space. The time span of exposed geology is limited to the middle Pleistocene through Holocene (<500 ka), and the island lies on an isolated platform (12 by 19 km). Altar Cave, formed within an oxygen isotope substage 5e eolianite (approximately 125 ka) of the Grotto Beach Formation on San Salvador, is a classic example of a flank margin cave that has been exposed during hillslope retreat. The nature of Altar Cave (restricted entrance, simplistic morphology, and easy access) facilitates a sedimentation study. Sediment profiles from trenches dug at three locations in Altar Cave show that the deposits in the cave formed as an early stage of development of a Holocene strand plain that is present today between the cave and the beach. Altar Cave was breached by Holocene coastal processes;14C dates show sand fill deposits in the cave to be Holocene (4.7 ka).14C dates, XRD, and geochemical analyses show the surficial sediment to be recent (0.6 ka), and that leaching has altered the bedrock floor of the cave. Petrologic study of the floor rock has provided evidence of autogenic sedimentation prior to breaching of the cave in the form of dissolution residuum accumulating during cave development. Petrologic analysis shows that this leaching has resulted in increased bedrock porosity below the sediment profile. Also, introduced organics have contaminated the late Pleistocene bedrock with young carbon, resulting in14 C ages of 14 ka at 0.3 m in depth and 28 ka at 1.3 m in depth. The results of this study demonstrate a potential method of porosity enhancement in young carbonates by vadose leaching. Porosity-enhanced zones have implications for our understanding of recharge to fresh-water lenses on carbonate islands.

Keywords

Holocene Trench Aragonite Ooids Freshwater Lens 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. BOARDMAN M.R., NEUMANN, A.C., and RASMUSSEN, K.A., 1988, Holocene sea level rise in the Bahamas.In J. Mylroie, ed., Proceedings of the 4th Symposium on the Geology of the Bahamas. Bahamian Field Station, San Salvador, Bahamas, p. 45–52.Google Scholar
  2. BOGLI, A., 1980, Karst hydrology and physical speleology. Springer-Verlag, New York, 284p.Google Scholar
  3. BROWN, T.W., 1984, Formation and development of caliche profiles in eolian deposits: San Salvador, the Bahamas.In J. Teeter, ed., Proceedings of the 2nd Symposium on the Geology of the Bahamas: CCFL Habamian Field Station, Fort Lauderdale, Florida, p. 245–264.Google Scholar
  4. CAREW, J.L. and MYLROIE, J.E., 1987, A refined geochronology for San Salvador Island, Bahamas.In H.A. Curran, ed., Proceedings of the Third Symposium on the Geology of the Bahamas: CCFL Bahamian Field Station, Ft. Lauderdale, Florida, p.35–44.Google Scholar
  5. CAREW, J.L. and MYLROIE, J.E., 1994, Geology and Karst of San Salvador Island, Bahamas: A Field Trip Guidebook. Bahamian Field Station, Ft. Lauderdale, Florida, 32p.Google Scholar
  6. CAREW, J.L. and MYLROIE, J.E., 1995, A stratigraphic and depositional model for the Bahama Islands.In H.A. Curran and B. White, eds., Terrestrial and Shallow Marine Geology of the Bahamas and Bermuda. Geological Society of America Special Paper, no. 300, p. 5–31.Google Scholar
  7. CHEN, J.H., CURRAN, H.A., WHITE, B., and WASSERBURG, G.J., 1988, Comparative morphologic analysis and geochronology for the development and decline of two Pleistocene coral reefs, San Salvador and Great Inagua Islands, Bahamas.In J. Mylroie, ed., Proceedings of the 4th Symposium on the Geology of the Bahamas. Bahamian Field Station, San Salvador, Bahamas, p. 107–117.Google Scholar
  8. FLOREA, L.J., MOORE, P.J., SEALE, L.D., BEDA, S., CRUMP, T., and MYLROIE, J.E., 2002, Caves of Hog Cay, San Salvador, Bahamas: Setting the Bahamian dry cave depth record. 2002 National Speleological Society Convention Program Guide, p.A-19.Google Scholar
  9. FLOREA, L.J., MYLROIE, J.E., and CAREW, J.L., 2001, Karst Genetic Model for the French Bay Breccia Deposits, San Salvador, Bahamas:Journal of Theoretical and Applied Karstology, v. 13–14, p.57–65.Google Scholar
  10. HARRIS, J.G., MYLROIE, J.E., and CAREW, J.L., 1995, Banana holes: Unique karst features of the Bahamas:Carbonates and Evaporites, v.10, no. 2, p.215–224.CrossRefGoogle Scholar
  11. HATTIN, D.H. and WARREN, V.L., 1989, Stratigraphic analysis of a fossilNeogoniolithon-capped patch reef and associated facies, San Salvador Island, Bahamas:Coral Reefs, v.8, p. 19–30.CrossRefGoogle Scholar
  12. JACKSON, J.A., 1997, Glossary of Geology. American Geological Institute, Alexandria, Virginia, 769 p.Google Scholar
  13. JENNINGS, J.N., 1968, Syngenetic karst in Austrialia.In P.W. Williams and J.N. Jennings, eds., Contributions to the study of karst:Research School of the Pacific Studies, Department of Geography Publication, v. 6, no. 5, p. 41–110.Google Scholar
  14. LONGMAN, M.W., 1980, Carbonate diagenetic textures from nearsurface diagenetic environments:American Association of Petroleum Geologists Bulletin, v.64, no. 4, p. 461–487.Google Scholar
  15. MOORE, P.J., SEALE, L.D., and MYLROIE, J.E., 2002, Pit Cave Development in Late Quaternary Eolian Calcarenites.In Geological Society of America, Abstract with Programs, v.34, p.A-35.Google Scholar
  16. MYLROIE, J.E. and CAREW, J.L., 1990, The flank margin model for dissolution cave development in carbonate platforms:Earth Surface Processes and Landforms, v. 15, p. 413–424.CrossRefGoogle Scholar
  17. MYLROIE, J.E. and CAREW, J.L., 1988, Solution conduits as indicators of Late Quaternary sea level position:Quaternary Science Reviews, v.7, p.55–64.CrossRefGoogle Scholar
  18. MYLROIE, J.E. and CAREW, J.L., 1991, Erosional notches in bahamian carbonates: Bioerosion or groundwater dissolution?In R.J. Bain, ed., Proceedings of the 5th Symposium on the Geology of the Bahamas. Bahamian Field Station, Port Charlotte, Florida, p. 185–191.Google Scholar
  19. MYLROIE, J.E. and CAREW, J.L., 1995, Chapter 3, Karst development on carbonate islands.In D.A. Budd, P.M. Harris, and A. Saller, eds., Unconformities and Porosity in Carbonate Strata. American Association of Petroleum Geologists Memoir, no. 63, p.55–76.Google Scholar
  20. MYLROIE, J.E., CAREW, J.L., and VACHER, H.L., 1995, Karst development in the bahamas and Bermuda.In H.A. Curran and B. White, eds., Terrestrial and shallow Marine Geology of the Bahamas and Bermuda. Geological Society of America Special Paper, no. 300, p. 251–267.Google Scholar
  21. PLUMMER, L.N., 1975, Mixing of sea water with calcium carbonate ground water.In E.H.T. Whitten, ed., Quantitative studies in geological sciences. Geological Society of America Memoir, no. 142, p. 219–236.Google Scholar
  22. REECE, M., MYLROIE, J.E., and JENSON, J.W., 2000, Cave and Karst Development of Guam: Implications for aquifer history.In National Speleological Society Convention Program Guide, p.A-15.Google Scholar
  23. ROBINSON, M.C. and DAVIS, R.L., 1999, Preliminary geographical information system analysis and maps of physical, hydrological, archaeological, and biological resources, San Salvador Island, Bahamas.In H.A. Curran and J.E. Mylroie, eds., Proceedings of the 9th Symposium on the Geology of the Bahamas and Other Carbonate Regions. Bahamian Field Station, San Salvador, Bahamas, p. 101–109.Google Scholar
  24. SANFORD, W.E. and KONIKOW, L.F., 1989, Porosity development in coastal carbonate aquifers:Geology, v.49, p. 249–252.CrossRefGoogle Scholar
  25. SCHWABE, S.J., CAREW, J.L., and MYLROIE, J.E., 1993, The petrology of Bahamian Pleistocene eolianites and flank margin caves: Implications for Late Quaternary island development.In B. White, ed., Proceedings of the 6th Symposium on the Geology of the Bahamas. Bahamian Field Station, Port Charlotte, Florida, p. 149–164.Google Scholar
  26. SMART, P.L. and WHITAKER, F.F., 1988, Controls on the rate and distribution of carbonate bedrock dissolution in the Bahamas.In J. Mylroie, ed., Proceedings of the 4th Symposium on the Geology of the Bahamas. Bahamian Field Station, San Salvador, Bahamas, p. 313–321.Google Scholar

Copyright information

© Springer 2004

Authors and Affiliations

  1. 1.Department of GeologyUniversity of South FloridaTampa
  2. 2.Department of GeosciencesMississippi State UniversityMississippi State, MS
  3. 3.Department of GeosciencesUniversity of ArkansasFayetteville

Personalised recommendations