to geologic time, having taken place only within the most
recent $7-kyr interval of Holocene flooding. Similar
progradational evolution is not possible at classic, steeply
inclined windward margins. Precipitous (e.g., volcanic)
slopes can only aggrade seaward slowly through coral
growth.
A nearshore rock ledge $2.5 km wide cuts into the seaward side of every 125-ka Florida Keys island (Figure 6a
and b). Its composition varies depending on northeast
(coral) or southwest (oolite) location. Its seaward edge is
$4 m deep. Its landward edge is the shoreline. By definition, an erosional surface cannot be dated. However, correlation of physical ledge characteristics with known
post-125-ka Pleistocene sea-level maxima in Florida and
a local Holocene sea-level curve provide the only possible
explanation as to how and when it formed. The ledge is
erosional and formed during the Holocene transgression
(Lidz et al., 2006).
Other aspects
Due to space limitations, other aspects of Florida Keys
reefs are not reviewed here. They include coral ecology
(Jaap, 1984); effects of sewage-disposal practices (Shinn
et al., 1994); diseases (Gladfelter, 1982); biochemical/
physical processes, and hydrology/groundwater flow
(Porter and Porter, 2002); sediment constituents
(Ginsburg, 1956); and reef management (Causey, 2002).
Summary
The late Quaternary depositional system along the shallow
Florida Keys shelf was physically and biologically
predisposed to replicate the structures, forms, and processes
of antecedent outer-shelf and shelf-edge morphologies. Primary controls were the position of sea-level maxima relative to antecedent topography. Reefs responded to the
resultant ambient geomorphic settings in their growth
habits, vitality, and distribution. Post-125-ka Pleistocene
settings offered accommodation space and protection, and
shelf-edge reefs flourished. The Holocene transgression
flooded the shelf, ultimately creating conditions that
allowed tidal exchange of coastal bay and cold gulf waters
with the reefs, causing their decline. The rock record shows
that reef growth varied locally through time—in location,
dimension, structure, geometry, depth, age distribution,
and accretionary direction. Yet the recurring regional theme
is the replication of antecedent facies and geomorphic
landforms, and thus repetition of stratigraphic shelf-edge
asymmetry. Florida Keys reef morphologies are distinctly
different from what would be generated at a classic steeply
inclined windward margin.
Bibliography
Causey, B., 2002. The role of the Florida Keys National Marine
Sanctuary in the South Florida Ecosystem restoration initiative.
In Porter, J. W., and Porter, K. G. (eds.), The Everglades, Florida
Bay and Coral Reefs of the Florida Keys: an Ecosystem Sourcebook. Boca Raton, FL: CRC Press, pp. 883–894.
Droxler, A. W., Alley, R. B., Howard, W. R., Poore, R. Z., and
Burckle, L. H., 2003a. Unique and exceptionally long interglacial Marine Isotope Stage 11: window into Earth warm
future climate. In Droxler, A. W., Poore, R. Z., and Burckle,
L. H. (eds.), Earth’s Climate and Orbital Eccentricity: the
Marine Isotope Stage 11 Question. Washington, DC:
American Geophysical Union. Geophysical Monograph,
Vol. 137, pp. 1–16.
Droxler, A. W., Poore, R. Z., and Burckle, L. H. (eds.), 2003b.
Earth’s Climate and Orbital Eccentricity: the Marine Isotope
Stage 11 Question. Washington, DC: American Geophysical
Union. Geophysical Monograph, Vol. 137, pp. 1–240.
Enos, P., and Perkins, R. D., 1977. Quaternary sedimentation
in South Florida. Geological Society of America Memoir, 147,
1–198.
Ginsburg, R. N., 1956. Environmental relationships of grain size
and constituent particles in some South Florida carbonate sediments. American Association of Petroleum Geologists Memoir,
47, 1–130.
Gladfelter, W. G., 1982. Whiteband disease in Acropora palmata:
implications for the structure and growth of shallow reefs. Bulletin of Marine Science, 32, 639–643.
Hoffmeister, J. E., Stockman, K. W., and Multer, H. G., 1967. Miami
Limestone of Florida and its Recent Bahamian counterpart. Geological Society of America Bulletin, 78, 175–190.
Jameson, S. C., Tupper, M. H., and Ridley, J. M., 2002. The three
screen doors: can marine “protected” areas be effective? Marine
Pollution Bulletin, 44, 1177–1183.
Jaap, W. C., 1984. The Ecology of the South Florida Coral
Reefs: a Community Profile. U.S. Department of the Interior,
Fish and Wildlife Service Report FWS/OBS-82/08
and Minerals Management Service Report MMS 84-0038,
pp. 1–138.
Lidz, B. H., 2004. Coral reef complexes at an atypical windward
platform margin: late Quaternary, Southeast Florida. Geological
Society of America Bulletin, 116(7), 974–988.
Lidz, B. H., 2006. Pleistocene corals of the Florida Keys: architects
of imposing reefs – why? Journal of Coastal Research, 22(4),
750–759.
Lidz, B. H., and Hallock, P., 2000. Sedimentary petrology of
a declining reef ecosystem, Florida reef tract (U.S.A.). Journal
of Coastal Research, 16(3), 675–697.
Lidz, B. H., Hine, A. C., Shinn, E. A., and Kindinger, J. L., 1991.
Multiple outer-reef tracts along the South Florida bank margin:
outlier reefs, a new windward-margin model. Geology, 19,
115–118.
Lidz, B. H., Reich, C. D., Peterson, R. L., and Shinn, E. A., 2006.
New maps, new information: coral reefs of the Florida Keys.
Journal of Coastal Research, 22(2), 61–83.
Lidz, B. H., Reich, C. D., and Shinn, E. A., 2003. Regional Quaternary submarine geomorphology in the Florida Keys. Geological
Society of America Bulletin, 115(7), 845–866.
Lidz, B. H., Reich, C. D., and Shinn, E. A., 2007. Systematic
mapping of bedrock and habitats along the Florida reef
tract: central Key Largo to Halfmoon Shoal (Gulf of Mexico). U.S. Geological Survey Professional Paper 1751. Available from World Wide Web: http://pubs.usgs.gov/pp/2007/
1751.
Lidz, B. H., Robbin, D. M., and Shinn, E. A., 1985. Holocene carbonate sedimentary petrology and facies accumulation, Looe
Key National Marine Sanctuary, Florida. Bulletin of Marine
Science, 36(3), 672–700.
Lidz, B. H., Shinn, E. A., Hudson, J. H., Multer, H. G., Halley,
R. B., and Robbin, D. M., 2008. Controls on late Quaternary
coral reefs of the Florida Keys. In Riegl, B. M., and Dodge,
R. E. (eds.), Coral Reefs of the USA. Coral Reefs of the World.
Berlin: Springer, Vol. 1, pp. 9–74.
414
FLORIDA KEYS
recent $7-kyr interval of Holocene flooding. Similar
progradational evolution is not possible at classic, steeply
inclined windward margins. Precipitous (e.g., volcanic)
slopes can only aggrade seaward slowly through coral
growth.
A nearshore rock ledge $2.5 km wide cuts into the seaward side of every 125-ka Florida Keys island (Figure 6a
and b). Its composition varies depending on northeast
(coral) or southwest (oolite) location. Its seaward edge is
$4 m deep. Its landward edge is the shoreline. By definition, an erosional surface cannot be dated. However, correlation of physical ledge characteristics with known
post-125-ka Pleistocene sea-level maxima in Florida and
a local Holocene sea-level curve provide the only possible
explanation as to how and when it formed. The ledge is
erosional and formed during the Holocene transgression
(Lidz et al., 2006).
Other aspects
Due to space limitations, other aspects of Florida Keys
reefs are not reviewed here. They include coral ecology
(Jaap, 1984); effects of sewage-disposal practices (Shinn
et al., 1994); diseases (Gladfelter, 1982); biochemical/
physical processes, and hydrology/groundwater flow
(Porter and Porter, 2002); sediment constituents
(Ginsburg, 1956); and reef management (Causey, 2002).
Summary
The late Quaternary depositional system along the shallow
Florida Keys shelf was physically and biologically
predisposed to replicate the structures, forms, and processes
of antecedent outer-shelf and shelf-edge morphologies. Primary controls were the position of sea-level maxima relative to antecedent topography. Reefs responded to the
resultant ambient geomorphic settings in their growth
habits, vitality, and distribution. Post-125-ka Pleistocene
settings offered accommodation space and protection, and
shelf-edge reefs flourished. The Holocene transgression
flooded the shelf, ultimately creating conditions that
allowed tidal exchange of coastal bay and cold gulf waters
with the reefs, causing their decline. The rock record shows
that reef growth varied locally through time—in location,
dimension, structure, geometry, depth, age distribution,
and accretionary direction. Yet the recurring regional theme
is the replication of antecedent facies and geomorphic
landforms, and thus repetition of stratigraphic shelf-edge
asymmetry. Florida Keys reef morphologies are distinctly
different from what would be generated at a classic steeply
inclined windward margin.
Bibliography
Causey, B., 2002. The role of the Florida Keys National Marine
Sanctuary in the South Florida Ecosystem restoration initiative.
In Porter, J. W., and Porter, K. G. (eds.), The Everglades, Florida
Bay and Coral Reefs of the Florida Keys: an Ecosystem Sourcebook. Boca Raton, FL: CRC Press, pp. 883–894.
Droxler, A. W., Alley, R. B., Howard, W. R., Poore, R. Z., and
Burckle, L. H., 2003a. Unique and exceptionally long interglacial Marine Isotope Stage 11: window into Earth warm
future climate. In Droxler, A. W., Poore, R. Z., and Burckle,
L. H. (eds.), Earth’s Climate and Orbital Eccentricity: the
Marine Isotope Stage 11 Question. Washington, DC:
American Geophysical Union. Geophysical Monograph,
Vol. 137, pp. 1–16.
Droxler, A. W., Poore, R. Z., and Burckle, L. H. (eds.), 2003b.
Earth’s Climate and Orbital Eccentricity: the Marine Isotope
Stage 11 Question. Washington, DC: American Geophysical
Union. Geophysical Monograph, Vol. 137, pp. 1–240.
Enos, P., and Perkins, R. D., 1977. Quaternary sedimentation
in South Florida. Geological Society of America Memoir, 147,
1–198.
Ginsburg, R. N., 1956. Environmental relationships of grain size
and constituent particles in some South Florida carbonate sediments. American Association of Petroleum Geologists Memoir,
47, 1–130.
Gladfelter, W. G., 1982. Whiteband disease in Acropora palmata:
implications for the structure and growth of shallow reefs. Bulletin of Marine Science, 32, 639–643.
Hoffmeister, J. E., Stockman, K. W., and Multer, H. G., 1967. Miami
Limestone of Florida and its Recent Bahamian counterpart. Geological Society of America Bulletin, 78, 175–190.
Jameson, S. C., Tupper, M. H., and Ridley, J. M., 2002. The three
screen doors: can marine “protected” areas be effective? Marine
Pollution Bulletin, 44, 1177–1183.
Jaap, W. C., 1984. The Ecology of the South Florida Coral
Reefs: a Community Profile. U.S. Department of the Interior,
Fish and Wildlife Service Report FWS/OBS-82/08
and Minerals Management Service Report MMS 84-0038,
pp. 1–138.
Lidz, B. H., 2004. Coral reef complexes at an atypical windward
platform margin: late Quaternary, Southeast Florida. Geological
Society of America Bulletin, 116(7), 974–988.
Lidz, B. H., 2006. Pleistocene corals of the Florida Keys: architects
of imposing reefs – why? Journal of Coastal Research, 22(4),
750–759.
Lidz, B. H., and Hallock, P., 2000. Sedimentary petrology of
a declining reef ecosystem, Florida reef tract (U.S.A.). Journal
of Coastal Research, 16(3), 675–697.
Lidz, B. H., Hine, A. C., Shinn, E. A., and Kindinger, J. L., 1991.
Multiple outer-reef tracts along the South Florida bank margin:
outlier reefs, a new windward-margin model. Geology, 19,
115–118.
Lidz, B. H., Reich, C. D., Peterson, R. L., and Shinn, E. A., 2006.
New maps, new information: coral reefs of the Florida Keys.
Journal of Coastal Research, 22(2), 61–83.
Lidz, B. H., Reich, C. D., and Shinn, E. A., 2003. Regional Quaternary submarine geomorphology in the Florida Keys. Geological
Society of America Bulletin, 115(7), 845–866.
Lidz, B. H., Reich, C. D., and Shinn, E. A., 2007. Systematic
mapping of bedrock and habitats along the Florida reef
tract: central Key Largo to Halfmoon Shoal (Gulf of Mexico). U.S. Geological Survey Professional Paper 1751. Available from World Wide Web: http://pubs.usgs.gov/pp/2007/
1751.
Lidz, B. H., Robbin, D. M., and Shinn, E. A., 1985. Holocene carbonate sedimentary petrology and facies accumulation, Looe
Key National Marine Sanctuary, Florida. Bulletin of Marine
Science, 36(3), 672–700.
Lidz, B. H., Shinn, E. A., Hudson, J. H., Multer, H. G., Halley,
R. B., and Robbin, D. M., 2008. Controls on late Quaternary
coral reefs of the Florida Keys. In Riegl, B. M., and Dodge,
R. E. (eds.), Coral Reefs of the USA. Coral Reefs of the World.
Berlin: Springer, Vol. 1, pp. 9–74.
414
FLORIDA KEYS