Come Explore Georgia's Natural History
  • Home: Georgias Fossils
  • 1: Georgia's Oldest Fossils; Archaeocyathids, At 513 Million Years Old
  • 2: Trilobites; 500 Million Years Ago
    • 2A; Murray County Stromatolites
    • 2B; A Trilobite Nest in Georgia
  • 3: Geologic Time
  • 4: Georgia's Oldest Vertebrate?
  • 5: Georgia Before the Dinosaurs
    • 5A; Georgia’s Pennsylvanian Plant Fossils
    • 5B: Carpentertypus durhami, Georgia’s Giant Insect, 315 Million Years Ago
    • 5C: Mississippian Trilobites in Northwest Georgia Describing the New Species Australosutura georgiana
    • 5D: Crinoids & Blastoids Of Northwest Georgia
    • 5E; Fossils of Northwest Georgia
  • *New* 5F: Pennsylvanian Plant Fossils of NW Georgia
  • 6: 200 Million Years Ago
  • 6A: Birth of the Atlantic Ocean
  • 7: Cretaceous Georgia, Dinosaurs & more
    • 7A: Georgias Pterosaur
    • 7B: So Many Sharks
    • 7C: Coelecanths
    • 7D: Xiphactinus vetus
    • 7E: Side-necked turtles
    • 7F: Marine Reptiles
    • 7G: Dinosaurs in Georgia
    • 7H: Deinosuchus schwimmeri in Recognition of Dr. David Schwimmer
    • 7I; The Blufftown Formation
    • 7J: New Species of Cretaceous Flowers Reported From Crawford County
    • 7K: Field Trip, Chattahoochee River Valley 1980
    • 7L: The Eutaw Formation
    • 7M: The Pio Nono Formation
    • 7N: Plant Fossils of Crawford County, GA
    • 7O; 1914 Report Georgia Plant Fossils From the Upper Cretaceous
    • 7P: Bill Montante's Mega "Gator" Tooth Discovery
  • 8: Suwannee Current, Gulf Trough, & Bridgeboro Limestone
  • 9: 60 million years ago, The Paleocene's Clayton Formation, A Report; By Hank Josey
    • 9A: The Georgia Turtle
    • 9B; Sassafras Hill Quarry Huber Formation Plant Fossils in Kaolin
  • 10: The Eocene; Georgia's Oldest Mammals
    • 10A: The Origins of Whales
  • 11: A Whale For Georgia
  • 12: Basilosaurids; The First Modern Whales
    • 12A: Basilosaurus cetoides
    • 12B: Basilotritus
    • 12C: Cynthiacetus (Revised)
    • 12D: Chrysocetus
    • 12E: The Redmond Mandible of Albany Ga
    • 12F: Houston County's Famous Great Whale Goes to the Smithsonian
  • 13: Ziggy and The Museum of Arts & Sciences, Macon, GA
  • 14: Late Eocene
    • 14A: Eocene Fossils & Stratigraphy
    • 14B; Fossils, Impacts, & Tektites Dating the Clinchfield Formation
    • 14C: The Tivola Limestone
    • 14C1: Oldest Oreodont in the Southeast & Georgia's first!
    • 14D: Twiggs Clay Vertebrates
    • 14E: Ocmulgee Formation Vertebrates
    • 14F; Sandersville Limestone, By Hank Josey
    • 14I: Dating Late Eocene Sediments
    • 14J: Georgia's Tektites; Georgiaites
    • 14K; Shell Bluff; Georgia's Most Historic Paleontology Site
    • 14L; Taylors Bluff, Paleo Paddling the Ocmulgee River
    • 14M; Eocene Terrestrial Mammals From Gordon, GA
    • 14N: Fossil Ridge, A Stratigraphic Study in Oaky Woods Wildlife Management Area
    • 14O; Georgia's First Entelodont
    • 14P: Historic Rich Hill
    • 14Q; Bibb County's Christy Hill, Clinchfield Formation Hilltop
    • 14R: Browns Mount, The Fall Line, Elevations, Uplifts, & Native Middle Georgians
  • 15: Early Oligocene
    • 15A: The Marianna Limestone
    • 15B; The Glendon Limestone
    • 15C: Undiffereniated Oligocene Residuum
    • 15D; Brissus bridgeboroensis; A New Echinoid Species From Georgia’s Bridgeboro Limestone
    • 15E: The Curious Steinkern Sea Biscuits of Red Dog Farm Road
    • 15F: Early Oligocene Gordian Knot
  • 16: Bonaire GA Entelodont
  • 17: The Whale Eating Shark
  • 18: Miocene Epoch; 23.3 to 5.3 Million Years Ago
    • 18A; Miocene Terrestrial Vertebrates
    • 18B; Paul Fell, Rockhouse Cave
    • 18C: The Marks Head Formation
    • 18D: Miocene Terrestrial Vertebrates of the Marks Head Formation
    • 18E: The Statenville Formation
    • 18F: Georgia’s 13 Million Year Old Dugong Metaxytherium calvertense
    • 18G: Gastropod Gulch, Julia Gardner, & Miocene Invertebrates In Decatur County
    • 18H; Bony Bluff, Rocky Ford, Echols County In Southernmost Georgia
  • 19: Pliocene Epoch; 5.3 to 2.5 Million years Ago
    • 19A: Two Small Primitive Horses from Taylor County Advance the Science of Georgia Geology
  • 20: The Pleistocene & Holocene Epochs, The Ice Ages
    • 20A; Clark Quarry's Mammoths & Bison
    • 20B: Pleistocene Vertebrate List
    • 20C: Georgia’s Eolian Dunes
    • 20D: Georgia’s Carolina Bays
    • 20E: Late Pleistocene Significant Events
    • 20F: Southeastern Thermal Enclave
    • 20G; Diamond Back Terrapins
    • 20H; A Kaolin Mine Beaver Dam
    • 20I; Pleistocene Vertebrate Fossils On Georgia’s Piedmont
    • 20J; Watkins Quarry Pleistocene Vertebrates, Glynn County, GA
    • 20K: Pleistocene Vertebrates from Coastal Georgia
    • 20L; Sandy Run Creek Core, Warner Robins, Houston County, GA
    • 20M: Bone Bed, Pleistocene, Coastal Georgia
    • 20N: Caribou & Elk Fossils from Georgia & Alabama
    • 20O; Tapir Veroensis, Walker County, Late Pleistocene
    • 20P; Ladds Pleistocene Vertebrates, Bartow County, GA
  • 21: Humans in Georgia
  • 22: Geology of the Coastal Plain, 1911
    • 22A: 1911 Cretaceous Fossil Locations
    • 22B: 1911 Eocene Fossil Locations
  • 23: GA County Localities, Houston County
  • 24: Science: Natural History & Geology
    • 24A; Podcast; The Tivola Whale of Houston County
    • 24B: Coastal Plain Correlation Chart
    • 24C: Presentation; Oaky Woods Stratigraphy
    • 24D: Physiographic Map of Georgia
    • 24E: Fossils of Oaky Woods
    • 24F: Collections & Stewardship of Georgia’s Fossils
    • 24G: I, Periarchus (A Fossil's Tale)
    • 24H: The Tivola Whales (April 2023 talk to the Mid-Georgia Gem & Mineral Society)
    • 24L: Needed; The Georgia Geologic Survey
    • 24M: Georgiacetus Presentation; A Whale for Georgia
    • 24N: Paul F. Huddlestun PhD, Georgia Coastal Plain Field Investigator >
      • 24N1: Late Eocene & Older... Coastal Plain Stratigraphy
      • 24N2: Gulf Trough Cores, Colquitt County, by Paul Huddlestun
      • 24N3; Washington County Core Logs By Paul Huddlestun
      • 24N4: Coastal Plain Core Logs by Paul F. Huddlestun
      • 24N5: Colquitt Core #6 By Paul Huddlestun
      • 24N6: Colquitt 10 & 7 Core
      • 24N7: Wayne County Core, Manningtown
      • 24N8: Gulf Trough Cores >
        • 24N8-1: Chatham County, Tybee Island Core
        • 24N8-2: Gulf Trough, USGS, Claxton, Evans County Core
        • 24N8-3: Blue Springs Landing Core, Screven County
        • 24N8-4: Toombs County Core, Baxley
    • 24O: Echinoids of Georgia, Cenozoic Era (Sand Dollars & Urchins) >
      • 24O1: Echinoids of Georgia, Cenozoic, By County
    • 24P; Exploring the Paleontology of Southernmost Georgia >
      • 24P1; Seminole County
      • 24P2: Decatur County Fossils & Natural History
      • 24P3: Grady County Blowing Caves, Forest Falls, Fossils & Natural History
  • 25: Education Material
    • 25A: My Field Kit; What You Need In The Field
    • 25B: Meet Crassostrea gigantissima, Georgia's Historic Giant Oyster
    • 25C: The Natural History & Fossils Record of Houston County, GA
    • 25D: Evidence for Evolution in Georgia's Fossil Record... A look at Teeth
    • 25E: Georgia's State Fossil; Shark Teeth
    • 25F: Georgia's Paleontology For Georgia's Classrooms
    • 25G: Library & School Presentations
    • 25H; An Introduction To Fossils; Presentation
  • 26: Georgia's Meteorites
    • 26A: Did I Find A Meteorite?
    • 26B: Georgia's Lost Meteorite
    • 26C: Georgia's Witnessed Meteorite Falls
    • 26D: The Sardis Iron, Georgia's Largest Meteorite

​6A: Birth of the Atlantic Ocean
By Thomas Thurman
​

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Our Hypsognathus knew only a tiny part of boundless Pangaea.

Boundless Pangaea; without ever seeing an ocean you could have walked from Australia, through Antarctica, through Africa, South America, Central America, North America, Canada, Greenland, Western Europe, Russia, China and beyond.

If we could visit Georgia during time of Hysognathus 200 million years ago we’d quickly notice that the Atlantic Ocean was missing. It simply didn’t yet exist; there was only Pangaea surrounded by a global ocean.

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Before the Atlantic Ocean could open Pangaea had to be split.

So how do you split a continent? 

We saw how 300 million years ago plate tectonics had formed Pangaea when the continents collided, buckling the terrain of Georgia’s Ridge and Valley Region.

The continents are restless. Today there is a volcanic seam along the length of the modern Atlantic Ocean floor which forms the Mid-Atlantic Ridge, the longest mountain chain in the world. It is completely submerged except for its northern-most limit in Iceland. 

Several tectonic plates are involved but essentially the Mid-Atlantic Ridge is where magma from Earth’s mantle rises through the Earth’s crust to the sea floor. Deep beneath the Atlantic’s waves it erupts as lava, providing new crustal material as it slowly pushes the continental plates apart. 

Today, the sea floor is spreading at about 2.5 centimeters (.98 inches) per year.



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The Mid-Atlantic Ridge created the Atlantic and began the slow process of splitting Pangaea. The splitting began with a rift, a seam, where rising forces were pushing the plates apart. 

The Dunbarton Basin and many other rift valleys along North America’s east coast represent early failures to split Pangaea. These are rifts that didn’t stick. 

About 200 million years ago one series of rifts did stick and began slowly splitting Pangaea, separating North America from Africa. Roughly 130 million years ago the Atlantic became a reality.

Dr. Burt Carter at Georgia Southwestern reminded me of this when he reviewed this website.

11/Dec/2014
Thomas
There’s another Africa connection.  The various rift basins in the eastern USA were failed attempts to open the Atlantic Ocean.  The basin that ultimately succeeded (where GA is concerned) was one whose walls were (very roughly, given subsequent erosion) where the continental slopes of N. America and Africa met.  That rift basin is still active as the Mid- Atlantic Ridge.  All the Atlantic oceanic crust between the original walls has been created since the Jurassic at that rift basin.  This is still one of the coolest realizations I have ever come to.
Burt
 
Think of that, the world’s longest mountain chain and hundreds of miles of sea floor which didn’t exist when our Hypsognathus lived. 
 
Dr. Pamela J. Gore, Professor of Geology at Georgia Perimeter College and author of Roadside Geology of Georgia (with William Witherspoon), is also very familiar with rift basins.   

17/Dec/2014
Thomas
Consider that Africa was attached to North America, with a volcanic island chain squeezed in between. A series of roughly parallel tension cracks began to form, as rifting began, and the cracks (at depth, not necessarily at the surface) filled with hot basaltic magma from below. These became the Triassic-Jurassic diabase dikes that we see exposed in some of the rock quarries and elsewhere in the Piedmont. One of these cracks became dominant with tremendous outpourings of basaltic lava, and became the Mid-Atlantic Ridge, forming the Atlantic Ocean basin.
Pamela
 
Pangaea was split, the Atlantic Ocean was born and the Earth moved closer to the world we all know and love.