ERTH 2401 Lecture Notes - Lecture 4: Petrified Wood, Pyrite, Eukaryote
29 Sep 2016
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Pyritization form of fossilization fills with pyrite to preserve the specimen (pyrite crystals) Carbonate (brain corals) rain water hardens the carbonate organisms. Dolotomized corals magnesium replaces the calcium in the calcite. Silicification - silica hardens; volcanism produces silica-rich ash and when it buries organisms/specimens it preserves them into fossils; in the cretaceous (lots of volcanos = lots of silica) very helpful in preserving the past. Agate quartz replaced by petrified wood due to silicification. Conclusion: the fossil record gives us a glimpse about what has once lived on this planet. We don"t get to see entire ecosystems only small amount based on what we find - try to rebuild the ecosystems. Paleontological resolution: 5-1 million species today, life originated 3. 5 billion years ago. Unsure about deep marine life and insects 1-3 billion species have come and gone; 99% from past are extinct (less than 1% were fossilized) only 10% have been discovered. Lecture #4 taxonomic order in the natural world.
