1. Fossilization and Fossils

2. ANY evidence of ancient life.
So what exactly is a fossil?
ANY evidence of ancient life.
Body fossil
teeth or bones
Trace fossil
cast, track, burrow
So what exactly is a fossil?

3. What is a scientist who studies fossils called? paleontologists
Next question…
What is a scientist who studies fossils called?
paleontologists
Archaeologists study the remains of ancient humans and their cultures.
Write this down; it is an IMPORTANT distinction!
Archae – beginning or ancient
Paleo – old; the term was originally used by Charles Lyell 1838

4. Fossils
If the layers of sedimentary rock are the pages that tell the story of the Earth, fossils are the words.
Literally, the word fossil means “dug up”.
Technically speaking fossils are remains of life that are at least 15,000 years old.
Preservation can include both altered and unaltered hard and soft parts. Fossils can also be casts and molds.
Found in shales, sandstones, limestones, amber, ash, nodules, tar, and ice.
The study of an organism from death to fossilization is called taphonomy (can include post-fossilization events as well).

5. Process of fossilization
Talk about the process

6. Process of fossilization
Fossilization depends on two critical steps:
• rapid burial by sediment
• mineralization
Helpful conditions:
• anoxia (lack of oxygen following burial)
• minimal disturbance subsequently
• mineral-rich water in sediment

7. Types of Fossilization
Unaltered Remains
Original material, including soft parts preserved
Rapid burial in ice, tar, or mummification
Recrystallization
Original material dissolved
New mineral deposited simultaneously
Permineralization
Minerals infill pores and holes
Molds and casts
Infilling with other material
Often, sedimentary infill
Carbonization
Preservation as thin films of carbon
Outline and sometimes detailed structures preserved
Permineralization: Minerals dissolved in water fill in the open spaces in bone. This makes the bone harder and heavier, but some original bone material may be retained.

8. Unaltered Soft Parts (Amber)
Mosquito
Scorpion
Feather

9. Unaltered Soft Parts (Ice)
“Blue Babe” bison
Siberian Wooly Mammoth

10. Unaltered Hard Parts: Tar and Anoxic Silt
Beetle in tar
LaBrea Tar Pit
Avitelmessus, NC
Fish from Messel, Germany

11. Unaltered Hard Parts (skeletal)
Smilodon
Ashfall Park
Columbian Mammoth

12. Recrystallization: Aragonite to Calcite
Pliocene
Busycon carica
Pterorhytis conradi
Chesapecten jeffersonius
Cretaceous
Eocene
Polinices sp
Urosalpinx sp.
Athleta petrosus

13. Recrystallization: Change in Crystal Structure
Cyclonema
Euproops
Mississippian Crinoids
Edrioasteroid
Dalmanites

14. Carbonization
Knightia
Spider
Dragonfly larva
Opabinia
Canadia

15. Carbonization
Sphenopteris

16. Permineralization Dinosaur Bone Shark Teeth Petrified Wood Brazil
Jurassic Pinecone
Permineralized Dinosaur Bone:
Cell Structure Preserved

17. Altered Hard Parts (replacement)
Silicified Mollusks
Silicified Stromatolite
Pyritization

18. Molds and Casts shell external mold cast interior steinkern shell
shell dissolves
sediment infilling
interior
steinkern
shell
shell
Sediment fills void
Shell dissolves

19. Casts and Steinkerns

20. Trace Fossils
Reflect the activity, or behavior, of organisms on land and in marine settings.
Exogenic – on the surface.
Endogenic – within the substrate.
Shape of the trace fossil does not always mirror the animal.
Trace fossils are named for their particular shape and form and not for the animal that made the trace.

21. Same animal may make several different types of trace fossils.

22. Trilobite resting trace

23. Trilobite trackway

24. Grazing trace

25. Other trace fossils include trackways on land (mostly dinosaur, reptile, and amphibian) and coprolites (fossilized feces, “poop”).

26. Dinosaur Ridge, CO
Glen Rose, TX

27. Coprolites Dinosaur Turtle Mammal Crocodile
Remember that feud between Cope and Marsh?
Mammal
Crocodile

28. Factors that Affect Fossilization
Animal contains hard parts
Death without scavenging or decomposition
Rapid burial after death