[Coral-List] Backstepping Coral Reefs
eugeneshinn at mail.usf.edu
Tue Oct 17 12:47:47 EDT 2017
Good to see that hurricane-induced backstepping is not limited to
Florida, (see Blanchon et al., 2017,_Retrograde accretion of a Caribbean
fringing reef controlled by hurricanes and sea-level rise._) Thank you,
Paul. I also thank Joseph Pawlik and Vassil Zlatarski for posting Reefs
of the Past: Videos of coral reefs of Florida Keys (1987) and Cuba
(1970s) in coral-list vol. 110, issue 7. Also see
https://www.youtube.com/watch?v=LIbmsHmuxWk&feature=youtu.be that shows backstepping at Grecian Rocks. John Halas shot the segment
that shows the backstepping illustration based on a transect of cores
across Grecian Rocks.
Our first hint that traditional textbook illustrations of reef
accumulation were different from what we see in the Holocene came with
passage of Hurricane Donna in 1960 (Ball et al., 1967). Similar effects
were also observed after Hurricane Betsy in 1965 (Perkins and Enos,
1968). In those days, we lacked technology for coring coral reefs. We
simply noted that many large head and branching corals from the seaward
side of Florida reefs had been transported and deposited on the landward
side of reefs. What we saw also explained the small coral-debris islands
on the landward side of many Florida Keys reefs. Thanks to MacIntyre and
Glynn (1976) we were all provided with the long-needed reef coring
Our very first test of our diver-operated core drill at Long Reef in the
upper Keys indicated backstepping (Shinn et al., 1977). Later, we
demonstrated backstepping at Carysfort Reef. Next was Grecian Rocks as
shown in the Grecian Rocks Reef video mentioned above. Since then, we
have seen backstepping in all the major reefs in the Florida Keys except
for Southeast Reef at Dry Tortugas, which showed both outstepping and
backstepping. Yes, hurricanes taught us a lot about reef growth and
geologic processes in the Florida Keys. The geologic effects of rising
sea level and repeated storms during the Holocene is one of the main
themes in our new book, /Geology of the Florida Keys /(Shinn and Lidz),
due out in February 2018 (University Press of Florida). The book is
dedicated to the memory and teachings of Robert N. Ginsburg, who
launched so many of us on our geological careers.Gene
Ball, M.M., Shinn, E.A., and Stockman, K.W., 1967, The geologic effects
of Hurricane Donna in south Florida. /Journal of Geology/, v. 75, p.
Macintyre I, G, Glynn P. W., 1976, Evolution of a modern Caribbean
fringing reef, Galeta Point, Panama. Am Assoc Petrol Geol Bull 60, pp
Perkins, R.D., and Enos, Paul, 1968, Hurricane Betsy in the
Florida-Bahamas area – geologic effects and comparison with Hurricane
Donna. /Journal of Geology/, v. 76, p. 710-717.
Shinn, E.A., 1980, Geologic history of Grecian Rocks, Key Largo Coral
Reef Marine Sanctuary: Bulletin of Marine Science, v. 30, no. 3, p. 646-656.
Shinn, E.A., 1988, The geology of the Florida Keys: Oceanus, v. 31, no.
1, p. 47-53.
Shinn, E.A., 2011, Spurs and Grooves, In: Encyclopedia of Earth Sciences
series, /Encyclopedia of Modern Coral Reefs, Structure, Form and
Processes/, David Hopley editor, Springer, p. 1032-1034.
Shinn, E.A., Halley, R.B., Hudson, J.H., and Lidz, B., 1977, Topographic
control and accumulation rate of some Holocene coral reefs — South
Florida and Dry Tortugas: International Coral Reef Symposium, 3rd,
Proceedings, Miami, Florida, v. 2, Geology, p. 1-8.
Shinn, E.A., Hudson, J.H., Robbin, D.M., and Lidz, B., 1981, Spurs and
grooves revisited — Construction versus erosion, Looe Key Reef, Florida:
International Coral Reef Symposium, 4th, Manila, Philippines,
Proceedings, v. 1, p. 475-483.
Shinn, E.A., and Jaap, W.C., 2005, Field guide to the major organisms
and processes building reefs and islands of the Dry Tortugas: The
Carnegie Dry Tortugas Laboratory:
SE Geological Society.
Shinn, E.A., Lidz, B.H., Kindinger, J.L., Hudson, J.H., and Halley,
R.B., 1989, Reefs of Florida and the Dry Tortugas, a guide to the modern
carbonate environments of the Florida Keys and the Dry Tortugas: Field
Trip Guidebook T176, 28^th International Geological Congress, American
Geophysical Union, Washington, D.C.
No Rocks, No Water, No Ecosystem (EAS)
E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eugeneshinn at mail.usf.edu>
Tel 727 553-1158
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