What are fossils?
• Definition: The remains or trace of organisms preserved from the geologic
past........
• Antiquity
• Fossils = sedimentary particles or fabric
How do fossils form?
• a very small fraction of organisms that have lived on Earth represented
as fossils......Why?
Taphonomic Loss
• Taphonomic processes - food webs, chemical cycling, decay, scavengers,
currents, waves, etc
• Taphonomic Loss = Bias in the fossil record……….
Rules of Taphonomy
• The probability of preservation is enhanced by
1. Hard parts
2. Rapid burial - removal from TAZ
Types of preservation...
Typical Fossils
• Unaltered Skeleton
• Petrification/Permineralization
- pores filled with silica
- light material becomes much heavier
• replacement (pyrite and quartz)
- atom for atom replacement
• molds and casts
- shell dissolved away - mold
- space filled with sediment -cast• Carbonization
- organics in plant preserved as carbon film
- similar process to forming coal