There is a Rare Paleocene Fossil Site at Ft. Gaines, Georgia

An outcropping of Paleocene fossils can be found at Ft. Gaines Georgia.  The Paleocene lasted from 65 million BP-55 million BP.

Science fiction stories featuring time-traveling heroes from the future often show them solving their own financial problems with knowledge of which stocks to pick.  This is a convenient, if overdone, subplot solution that gives the hero unlimited money without having to muddy up the plot by having the character engage in a mundane occupation.  If I could time travel to just 2 weeks ago, I could have invested in Ohio Arts, the makers of the Etch-A-Sketch.  Its price has tripled from $4 a share to $12 a share after the Etch-A-Sketch became the symbol of a flip-flopping presidential candidate.  The Etch-A-Sketch is a neat toy for kids who can draw a scene, shake it up to erase it, and start over.  This reminds me of a geological era–the Paleocene.

The famous asteroid collision that wiped out the dinosaurs occurred about 65 million years ago and is known as the K-T impact.  Scientists believe the impact cooked the atmosphere, and the only organisms able to survive were those burrowed underground or living in water.  100% of the dinosaurs and 57% of the megaflora became extinct.  Like an Etch-A-Sketch drawing, most life on earth simply vanished.  Crocodiles, turtles, birds nesting in burrows, fossorial mammals, insects, and plant seeds survived and provided the basis for a redrawing of the ecological picture.

Ferns thrive in ashy soils, and there was a lot of ash after the fires of the K-T impact.  They were the first plants to dominate the landscape when they grew their new shoots into an environment with no shady competition.  Seeds of surviving plants germinated, and plant species eventually evolved to fill new ecological niches left vacant by the mass extinctions.  The same was true for animals.  All animals alive today evolved from detritus feeders because for decades dead plant material formed the base of the food chain.

The rapid evolutionary response to the K-T impact makes the Paleocene a fascinating period of time for paleoecologists to study.  Unfortunately, most paleocene fossils in southeastern North America are almost a mile underground and inaccessible.  However, there are 4 small localities where the face of the land has eroded into Paleocene outcroppings.  A couple are in Mississippi, 1 is in Alabama, and the 4th is located in Ft. Gaines, Georgia.  For the layman there’s not much to get excited about here–the fossils consist of foraminifera (single-celled protozoa with shells) and pollen.  But for the paleoecologist these microfossils are thrilling.

Pollen and foraminifera reveal quite a lot about the environment of the Paleocene.  The Paleocene flora consisted of a strange mix of temperate and tropical species, though the former were probably adapted to much warmer temperatures than those of today.  Plants from the walnut, birch, and elm families grew side-by-side with those from the mango-cashew, balsa, sweetsop, palm, frankinscense, and tea families.  The Paleocene lasted for 10 million years, and the pollen record shows that plant diversity steadily increased by 15% until the PETM.  The PETM is an acronym for the Paleocene-Eocene Thermal Maximum.  For some undetermined reason average global temperatures suddenly increased by 10-20 degrees Fahrenheit, and CO2 levels in the atmosphere spiked too.  This either directly or indirectly caused the extinction of 38% of plant species and is known as the terminal Paleocene extinction event.  Scientists think there are several possible ecological causes for the floral extinctions:  The climate became drier to the detriment of water-loving species of plants, the increase in CO2 levels in the atmosphere may have favored some species of plants over others, and new species of animals evolved that the plants had no defenses against.  Scientists don’t think the climate changed faster than the plants could adjust their geographical range to, but this may have been a an indirect contributing factor.

Only 1 Paleocene vertebrate fossil has ever been discovered in southeastern North America.  In 1932 at Caddo Parrish, Louisiana while drilling a core for an oil well, workers accidentally hooked the skull of Ansinochus fortunatus–a kind of archaic ungulate.  Half of the southeast was under ocean water during the Paleocene, but uplands hosted an interesting cavalcade of primitive mammals, if we assume they were similar to those found at Paleocene fossil sites in other parts of the world.  Marsupials, monotremes, and multituberculates were common.  Multituberculates were a family of rodent-like mammals that lived in the tree tops of the Cretaceous but became extinct during the early Eocene.  Though they resembled rodents, they were not placental mammals and therefore not at all closely related to any extant family of mammals.  Insectivores were the evolutionary base for many placental mammals including the nyctertheridae (pre-bat) and tree shrews (pre-primate).  Condylarths were archaic hooved animals.  Extinct creodonts were the dominant meat-eaters along with primitive carnivores and carnivorous ungulates.  Pantedonts, uinitheres, and xenoungulates were the first large herbivores to evolve following the extinction of the dinosaurs.  The below link is an excellent source of information on Paleocene vertebrate life.

http://www.paleocene-mammals.de/pal_intro.htm

Reference:

Harrington, Guy; and Carlos Jaramill

“Paratropical Floral Extinction in the Late Paleocene-Early Eocene”

Journal of the Geological Society V. 164 2007 pp. 323-332

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