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Fossils

Fossils. Evidence of Past Life that lived before recorded history, usually found in sedimentary rocks. Fossils can indicate:. 1. Time 2. Past environments 3. Evolution. Fossil formation. 1. Organism had to live 2. Organism had to die

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Fossils

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  1. Fossils Evidence of Past Life that lived before recorded history, usually found in sedimentary rocks

  2. Fossils can indicate: • 1. Time • 2. Past environments • 3. Evolution

  3. Fossil formation • 1. Organism had to live • 2. Organism had to die • 3. Remains had to be buried quickly, before it decayed, or was eaten • 4. Not many fossils remain today, considering the billions of organisms that have lived on Earth

  4. Eastern Virginia • Carmel Church Quarry, Caroline County (used by the Virginia Museum of Natural History) • Carters Grove • Caledon Natural Area • Westmoreland and York River State Parks • Chippokes Plantation State Park

  5. Eastern Virginia • Cedar Island, • Eastern Shore “Fossil Shell”

  6. Layers in Virginia • Tabb – about 1 MYA • James City • Windsor • Yorktown • Eastover • Calvert • Pungo River – about 20 MYA

  7. Fossil Museums in Virginia • Virginia Museum of Natural History, Martinsville • Museum of Geosciences, Virginia Tech • Museum of the Middle Appalachians, Saltville Museum of the Middle Appalachians

  8. Types of Fossils • 1. Entire Organism • A. Ice – Wooly Mammoth • B. Amber – insects • C. Tar Pit – saber toothed tiger These fossils have the possibility of DNA evidence

  9. Types of Fossils • 2. Unaltered hard parts • a. Bones • b. Teeth • c. shells Chesapectenjeffersonius, Virginia State Fossil

  10. Types of Fossils • 3. Replacement – Petrification • a. Almost any fossil can be petrified • b. Cells are slowly replaced by minerals • c. Remains are literally turned to stone • d. Shows exact surface details, but inner features are lost • e. No DNA evidence

  11. Types of Fossils • 4. Mold • a. Hollow shape in rock • b. The fossil was removed by water • c. Shows surface details • 5. Cast • a. Mold is slowly filled in by minerals • b. Fills the entire mold • c. Surface features perfectly preserved Mold Cast

  12. Types of Fossils • 6. Carbonized • a. Only a thin film of carbon remains • b. Seen with thin, delicate organisms • c. Fish, leaves

  13. Types of Fossils • 7. Trace • A. Evidence, but not the organism itself • B. Tracks, footprints • C. Coprolite • D. Burrows, worm casts

  14. Special Fossils • 1. Facies Fossil • a. Long life span • b. Narrow distribution • c. Indicates a certain environment Lingula, good facies Homo, bad facies

  15. Special Fossils • 2. Index Fossil • a. Short life span • b. Wide distribution • c. Indicates a certain time period Ecphora: 3 – 5 mya Good index Sharks: 0 – 350 mya Bad index

  16. Special Fossils • Index fossils can be used to date rocks to a certain time period • when a rock contains several fossils, the time period when they all lived is the time period that the rock was formed

  17. Geologic History

  18. A B C D • Index Fossils Found in same rock A – lived from Tr – Te B - lived from J – Cr C – lived from Tr – J D – lived from J – Te Rock must have been formed in the Jurassic period Tertiary Cretaceous Jurassic Triassic

  19. Resources • Fossil Collecting in the Mid Atlantic States, by Jasper Burns • www.Fossilsites.com/index.html - search fossil sites by state • www.vmnh.net - Virginia Museum of Natural History • www.fossilandnaturetrips.com/ - mid Atlantic fossil hunting trips • www.aurorafossilmuseum.com/ - good identification chart of shark teeth

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