from: georgiasfossils.com an introduction to georgia’s fossils fossils as evidence of organisms...

From: GeorgiasFossils.com

An Introduction to Georgia’s Fossils

Fossils as Evidence of Organisms That Lived Long Ago

Published by Georgiasfossils.com

This should not be considered a complete list Georgia’s fish and shark fossils, rather it was compiled from collected

material which was adequately illustrated.

Special Thanks to:Dr. David Schwimmer, Columbus State UniversityDr. Dennis Parmley; Georgia College and State UniversityDr. Richard Hulbert, University of Florida and Florida Museum of Natural HistoryDr. Burt Carter; Georgia Southwestern State University


Georgia’s Fossil Record , PartialSome of the animals known to occur in GeorgiaCommon name Years AgoHumans 17,000Columbian Mammoth 17,000Giant Sloth 20,000Giant Bison 21,000Beaked Whale 1 millionRhinoceros 4 millionHorses (Hipparion) 4 millionKiller Sperm Whale 10 millionGiant Shark (megalodon) 10 millionTerminator Pigs (Entelodonts) 35 millionEarly whales (Basilosaurus) 35 millionManatees (Siren) 35 millionMany Sharks 35 millionLand & Sea Turtles 35 millionBrontothere (Rhino-like) 35 millionLarge Snakes (15 feet) 35 millionAuks (warm water) 35 millionProto-whales (Georgiacetus) 40 millionBillfish (Cylindracanthus rectus) 40 millionTurtle (Agomphus oxysternum) 61 millionOstrich Dinosaurs 78 millionHadrosaurs 78 millionAppalachiosaurus 78 millionMany Sharks 78 millionGiant Coelacanth 83 millionPterosaurs 83 millionHypsognathus 200 millionTrilobites 500 million


The Different Types of Fossils

What is a Fossil?A fossil is the evidence of ancient life, of organisms which lived long ago. It is the remains of an animal, animal activity or plant which has been persevered.

There are some basic types:•Invertebrate Fossils; lacking a back bone•Vertebrate Fossils; possessing a backbone•Plant Fossils; as petrified wood and leaf impressions•Trace Fossils; tracks, burrows, tunnels…

There are three basic environments for organisms as applied to fossils…

•Aquatic; freshwater•Marine; saltwater•Terrestrial; landTypically, these terms are combined to explain

both the basic type of fossil and its basic environment, such as;

•Marine Invertebrate•Aquatic Plant•Terrestrial Vertebrate

The Fossil RecordThe fossil record is the history of fossils over time. Georgia’s fossil record stretches back 500 million years


Georgia has a rich record of marine invertebrate fossils including clams, oysters, sea snails, corals, sand dollars, and scallops. There are many others from a wide span of time, each with a story to tell.

InvertebratesInvertebrates are animals which do not have a backbone. There are many kinds of invertebrates.

•Terrestrial invertebrates would include insects, spiders, worms and worms.•Marine invertebrates would include starfish, sand dollars, sea shells and crustaceans (crabs, lobsters & shrimp); there are many others.•Aquatic Invertebrates would also include some crustaceans ( fresh water shrimp), insects, snails and clams.


“Vertebrate”, means an animal which has a backbone, or spinal column. The most common vertebrate fossils are teeth and bones. Teeth are the hardest things the body makes, so they are the most easily preserved.

Vertebrate Fossils

Georgia’s most common vertebrate fossil is the shark’s tooth, a marine vertebrate. This is our State Fossil. Georgia also has terrestrial vertebrates in its fossil record, including dinosaurs.


Plant FossilsPlant fossils are well known from Georgia. Petrified wood is a plant fossil; it is wood which has absorbed minerals and slowly turned to stone. Leaves of plants can also form fossils, usually as impressions.

This artwork by Xavier Sims depicts some of the 78 million year old plant fossils from the Columbus, Georgia area as described by Georgia researchers in 1911. When these plants lived, dinosaurs walked Georgia.


Trace Fossils

Trace fossils are the last main group. These are not the remains of animals, but the evidence of their presence and activity.

Burrows and tunnels are the most common marine trace fossils. Animal tracks are the most common terrestrial trace fossils.

Coprolites are fossilized poop (funny huh?), but these are important as they are used to study what animals ate.

Paleontologist often use trace fossils to understand behavior.


A “paleontologist” is a scientist which studies fossils. They are also called paleo-biologist.“Paleo” means ancient.

Paleontologist

There are vertebrate paleontologist, invertebrate paleontologist and paleo-botanist. A botanist studies plants, a paleo-botanist studies ancient plants.


The Preservation of Fossils; Step 1How do fossils form? Burial.

All fossils are rare. Very few organism leave fossils when they die. The conditions for forming fossils are rare, but when those conditions are met, many fossils can form.

When most organisms die the processes of decay and scavenging quickly consume the remains. Other plants and animals are nourished.

For a fossil to form, the remains of the animal or plant must be preserved first from decay and savaging, this usually means natural burial of some sort.

Then those remains may form fossils.

The most common form of burial involves water. Organisms are buried when they get caught and die in rivers, where they are buried in the sediments. This can often happen along coastlines where rivers empty into seas and deposit sediments.

Hipparion horse fossils are known from Georgia’s sediments, where they were transported by water.


The Preservation of Fossils; Step 2How do fossils form? Mineralization

If you spill grape juice on your shirt, your shirt will dry out, but the grape stain will remain.

If you mix water and salt, then drip it onto a hard surface, the water will evaporate leaving the salt behind…salt is a mineral (primarily, sodium chloride). This is one way the minerals form, they are left behind by water.

Many kinds of minerals can turn animal or plant remains into fossils.

Over time, the remains absorb the minerals around them.

Think of the way bread absorbs jelly or paper absorbs glue. The same thing happens to a bone, tooth, branch or leaf when it is buried. Bread and paper do this in just a few minutes, bones and wood have thousands or millions of years to do this.

The remains absorb minerals which are already around them and slowly turn to stone.


MoldsSometimes a fossil is completely dissolved and only leaves the shape of the organism in the matrix as a cavity or negative. This is a mold.

The “matrix” is the rock hosting the fossil. Molds of sea shells are common and frequently preserve very fine detail.

CastsSometimes a cavity (including a mold of a fossil) is filled with sediments and creates a duplicate. This is called a cast.

In Georgia, you will often see casts formed when fine sediments fill cavities made by dissolved shells and later harden into rock.

Molds, Casts & Impressions


Invertebrate Fossils

Dating & Environments

Marine invertebrate fossils occur around the world and in Georgia. They can tell us many things. For one thing, small invertebrate species appear and go extinct frequently, constantly evolving new forms and leaving a fossil record of their history.

Stratigraphy:

Fossils are arranged in beds, or layers, like a stack of pancakes with the oldest on the bottom and the freshest on top. The study of these beds is called stratigraphy.

Dating by mineral content:

One way fossils can be dated is through their mineral content. Minerals begin to decay soon after they are formed. Different minerals decay at different rates, all decay very slowly, many of these decay rates can be measured by scientists. You can often measure how much that mineral has decayed since it formed. If it has one million years worth of decay, then that mineral formed one million years ago and the fossil is one million years old.

Combining stratigraphy & mineral dating:

Dating methods have been done on many species in the fossil record. Once you know how old a particular species is, you also know the age of other species present in the same layer. Anytime you see one of these fossils, you know the age of the sediments holding it. From:

GeorgiasFossils.com

Paleo-environments

Sometimes conditions are right and great quantities of fossils can form in one bed.

By comparing fossils to modern species, we can learn what conditions a particular fossil likely preferred.

Then when scientists find many fossils together, all of which prefer a certain climate, they know what the climate was when those fossils lived.

In Georgia’s southern Houston County you’ll find exposures of the Tivola Limestone, it is very rich in small invertebrate fossils.

Research shows that these animals preferred a tropical or sub-tropical sea.

These beds have been dated to around 35 million years ago. At that time Houston County was covered by a tropical or subtropical sea. From:

GeorgiasFossils.com

The stratigraphy of the Cemex limestone quarry in Houston County Georgia where the Tivola Limestone is mined. See the Tivola Limestone in yellow.


Georgia’s Oldest Fossils

When they lived, 500 million years ago, this was the floor of a shallow sea and there were neither bones nor trees on all the Earth. Neither had yet emerged.

The Appalachian Mountains, one of the oldest mountain ranges in the world today, was still hundreds of millions of years in the future and because of continental drift Georgia was deep in the Southern Hemisphere.

500 million years agoTrilobites have long been collected from Northwest Georgia. This is a small specimen, some are much larger.


Continental Drift

Imagine that you put together two puzzles and then slid them across the table until their edges touched.

If you keep pushing the edges together they will begin to flex and then will fold and pieces of the puzzle will buckle and one puzzle will likely slide beneath the other.

This is what happened when continents collide; mountains are built this way, the pieces of the puzzle lying on top would be like mountains pushed up on the edges of a continental collision.

The continents move, very slowly. More slowly than your fingernails grow. Sometimes they crash together. Sometimes they pull apart. This movement is called Continental Drift or Plate Tectonics.

When they come together and coastlines are pushed against each other, the ground will buckled and fold.

Now take one puzzle, all put together, and slowly try to pull it apart, gaps start to open between the pieces...

This is what happened when the continents move away from each other. Gaps, or valleys, appear in the ground. These are called rift valleys. The Atlantic Ocean began as a rift valley in Pangaea. From:

GeorgiasFossils.com

Rift Valleys Dr. Tim Chowns is a Professor of Geology for the University of West Georgia; he reports that the skull of a 200 million year old Triassic reptile, genus Hypsognathus, was recovered from a deep drill sample near the Savannah River in South Carolina at a depth of 2,016 feet (nearly half a mile deep).

Hypsognathus was a primitive reptile about 13 inches long and very much like a modern lizard, though they are unrelated. Dr. Chowns reports that the area producing the fossil is a buried rift valley.

Rift Valleys form when continents move away from each other, The forces of continental drift tried to tear the Southeast apart.

When Hypsognathus there wasn’t yet a flower on all the Earth, the flowering plants had yet to emerge.


When sea levels were high.

When sea levels were high a, fertile shallow sea covered much of North America as well as all of southern Georgia and Florida.

This was a tropical, or sub-tropical sea. During this time the powerful Suwannee Current crossed South Georgia, connecting the Gulf of Mexico to The Atlantic.

This sea also covered much of the interior of the USA and Canada as the Western Interior Seaway, Hudson Seaway and Labrador Seaway.


Ever Changing EarthThe Earth changes, and is still changing.

Climates change.

•The world cools and ice ages come; a vast amount of sea water gets trapped as glaciers. The glaciers grow from the poles toward the equator.

•The world warms and ice retreats, glaciers melt away and the water returns to the seas, many times the earth has been so warm that the both poles were ice free.

Sea levels rise and fall, in response to cooling and warming.

•Sometimes sea levels are so low during the ice ages that the coastline moves 30 or 40 miles further out to sea, all the way to the continental shelf.

•Sometimes sea levels are so high that the coastline rests on Georgia’s Fall Line.

•There have been at least 27 shifts in sea levels in the last 2 million years.

The continents move.

•Sometimes they come together, raising mountains.•Sometimes they move apart, opening valleys, even oceans.

Fossils often record these events.


The Georgia WhaleIn 1983 a mass of whale fossils was discovered in Burke County Georgia during the construction of Nuclear Power Plant Vogtle.

Researchers would show that this was a proto-whale (early whale) previously unknown to science. It was named Georgiacetus.

Eventually, fossils from three separate individuals were recovered.

How fossils show changeThe Georgiacetus fossils were found 93 miles inland from the modern coastline.

The invertebrate fossils found with the proto-whales showed that they died offshore, maybe 30 miles south of the shoreline that they knew.

When these whales lived the shoreline rested on or north of the Fall Line.


Appalachiosaurus lived 78 million years ago and was discovered by a team including Dr. David Schwimmer at Columbus State University from a nearly complete skeleton of a young animal (juvenile) in Alabama, it also occurs in Georgia. Appalachiosaurus is a ancestor to Tyrannosaurus Rex. Artwork by Jordon Walker.


A 35 million year old brontothere tooth was found near Gordon, Georgia by a research team including Dr. Dennis Parmley of Georgia College and State University. Artwork by Quentin Lonon


Dr. David Schwimmer has reported Ostrich Dinosaurs (Ornithomimisauridae) from 78 million year old sediments in West Georgia near Columbus, Georgia . Artwork by Hasani Jones.


Dr. David Schwimmer at Columbus State University has also reported 83 million year old Pterosaur from the Columbus area, they were likely pterodactyls, though the species could not be determined.

A larger pterosaur is imaged here.

Artwork by Hasani Jones


Dr. Schwimmer at Columbus State University also reported a population of goblin sharks (Scapanorhynchus texanus) from 78 million year old sediments near Columbus, Ga.

Artwork by Hasani Jones


Columbian mammoths (Mammuthus columbi) have been reported from the Savannah area by Dr. Al Mead at Georgia College State University in Milledgeville. This large animal also occurs in other Georgia locations.

Artwork by Elisa Boswell


from: georgiasfossils.com an introduction to georgia’s fossils fossils as evidence of organisms...

Documents

georgias fossils fossils

history of fossils

shark fossils

common vertebrate fossils

backbone plant fossils

invertebrates invertebrates

bone vertebrate fossils

different types of fossils