"Either sea level was that high or there is some kind of uplift," said geologist Peter Adams at the University of Florida at Gainesville. Adams is the lead author of a paper on the matter in the June issue of the journal Geology.
Since tectonic collision can't be called on to explain the matter, Adams decided to put the cavern-ridden rebound idea -- first proposed in 1984 by his co-author Neil Updyke -- to the test with a model.
The numerical model combined estimated sea level fluctuations over more than a million years, the length of time the land has been out of the water, rainfall, cave-formation rates and isostatic uplift to see if the idea has any legs.
"I'm just seeing if mechanically those ridges fit with the ages," said Adams.
The model suggests the ages of north Florida's Trail Ridge, Penholoway Terrace and Talbot terrace are 1.44 million, 408,000, and 120,000 years old respectively. That basically matches the fossil evidence in the rocks, Adams said.
"They did a good job with this," commented veteran Florida geologist Thomas Scott, formerly of the Florida Geological Survey and author of the book "Roadside Geology of Florida." The model is a good "proof of concept" study, he said.