10. fossil notes

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10. fossil notes

  1. 1. Fossils
  2. 2. Fossils:  The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock, can be used to identify the relative or absolute age of a rock
  3. 3. Paleontology  The study of fossils and ancient organisms
  4. 4. Mummification  Typically occurs in dry places where bacteria can’t survive
  5. 5. Amber:  Organisms trapped in ancient tree sap
  6. 6. Tar Seeps:  Thick petroleum that comes to the surface and is covered by water
  7. 7. Freezing:  Low temperatures protect an organism from bacteria
  8. 8. Petrification:  Minerals in water seep in and replace original organic materials
  9. 9. Imprints:  Carbonized imprints left behind after the organic material decays
  10. 10. Molds and Casts  Molds are empty impressions filled by rock while casts are replica of their original organism
  11. 11. Gastroliths:  Smooth stones in the digestive system of dinosaurs to help grind up and digest food
  12. 12. Trace Fossil:  A fossilized mark that formed in sedimentary rock by the movement of an animal on or within a soft sediment (i.e. a footprint)
  13. 13. Index Fossils:  A fossil that is used to establish an age of a rock because it is distinct, abundant, and widespread, and only existed for a short span of geological time, can be used to determine the absolute age of a rock layer
  14. 14. Evidence of Plate Tectonics  Fossils of marine life on mountain tops and shallow water organisms in deep water prove crustal movement
  15. 15. Key Beds:  Rock layers that contain distinctive characteristics (such as volcanic ash) or fossil content that allow one to correlate rock layers in different areas

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