Professor uncovers age of Beach
Ever wonder how old Estero Island could be?
Town officials have and sought information related to determining the age of the island from a scientific standpoint.
On Monday night, Dr. Frank Stapor presented his findings after his work was funded by the Town of Fort Myers Beach on a request made by Friends of Matanzas Pass Preserve’s Jim Rodwell. Dr. Stapor specializes in sedimentation and used that approach to determine the age of sediments from beach ridges in Matanzas Pass Preserve to develop a model of geological evaluation of the island.
Dating technique results that were called “cutting edge” reveal Fort Myers Beach is roughly 1,500 years old. Three core samples (A, B and C) were taken from the Preserve. They were sent to the University of Georgia luminosity laboratory, and data was returned and presented to the Beach Council.
“I want you to notice that it is 1,430 years plus/minus 50 years. The calendar age for that is AD 570,” said Stapor, viewing a chart. “That also turns out to be the average age of the occupation of your Mound (House) site. This particular dating technique is the gold standard for doing coastal geochronology.”
Stapor, who was raised in Fort Myers in the 1950s, is heralded as an expert in coastal geology. He retired from Tennessee Tech University in 2010, and has been performing age dating studies in Lee County, including Sanibel, Cayo Costa, Captiva and Gasparilla. He has also worked indirectly with state archaeologists on the Mound House.
Stapor did say he was surprised that Estero Island was not older.
“My guess at that time was that we would be looking at an island that probably was at least 2,000 years old,” he said.
Optically stimulated luminescence was cited as the best procedure for an island dating technique because it estimates the time elapsed to sunlight. This dating technique is different than radiocarbon, C14, which estimates the age of shell or wood fragment contained within a deposit, which results in a maximum age (the sand body can be no older and may be younger).
“In the case of OSL, we can actually date the last time the sand saw sunlight,” said Stapor. “What causes the luminescence to release is a blast of light. In order to make this technique work, we have to take a sample in the dark, so the work was done at night. The OSL technique actually dates the time of deposition.”
Stapor plans on publishing his findings in a professional journal, possibly the Journal of Coastal Geology.