UF Pine lsland Pollen Study Leads To Revision Of State's Ancient Geography

A new University of Florida study of 45-million-year-old pollen from Pine Island west of Fort Myers has led to a new understanding of the state's geologic history, showing Florida could be 10 million to 15 million years older than previously believed. The discovery of land in Florida during the early Eocene opens the possibility for researchers to explore the existence of land animals at that time, including their adaptation, evolution and dispersal until the present.

Florida Museum of Natural History vertebrate paleontologist Jonathan Bloch, who was not involved in the current study, said he is especially interested in the finding and future related research.

"As a paleontologist who studies the evolution of mammals, my first question is 'OK, if there was land here at that time, what kinds of animals lived here?' " Bloch said. "Most of our current understanding of the evolution of early mammals comes from fossils discovered out west."

The study in the current issue of the journal Palynology by David Jarzen, a research scientist at the Florida Museum of Natural History on the UF campus, determined sediment collected from a deep injection well contained local, land-based pollen, disproving the popular belief Florida was underwater 45 million years ago during the early Eocene.

"When I got the sample, I could actually break it apart with my fingers," Jarzen said. "It wasn't just land, it was low-lying land with boggy conditions and near shore because it showed marine influence."

Until recently, Florida was believed to have been submerged until the Oligocene epoch, 23 million to 34 million years ago, Jarzen said. The 2010 study of the Pine Island sample from the Oldsmar Formation dates Florida's land from the early Eocene, about 10 million to 15 million years earlier than determined in a 2006 study of pollen and invertebrate fossils from the Avon Park Formation in west central Florida by Jarzen and former Florida Museum scientist David Dilcher.

"What we thought we knew was an incomplete body of information," said Fredrick Rich, a professor of geology in the department of geology and geography at Georgia Southern University. "Those terrestrial trees, shrubs and herbs didn't live out there all by themselves. I envision a small key, or maybe several small keys just like the islands in Florida Bay.

The study appears in the December 2010 edition of the bi-annual journal, which was distributed in January.