EOSC 116 Chapter Notes - Chapter F: Trace Fossil, Taphonomy, Creatures 3
8 Dec 2015
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Wednesday, december 2, 2015. Learning goals: define what a fossil is and summarize their various modes of formation. Physical remains of earth"s past biosphere. Any trace of past life. Two broad categories of fossils. Bones, shells, gastroliths (stomach stones), skin impression, coprolites (fossil feces) and eggs. Trace fossil / inchofossil. Tracks and trails left by organisms and preserved in the geological record. Various modes of formation. The replacement of organic material by inorganic minerals. Organic - > bones - > calcium phosphate. Inorganic mineralizing media - > calcite, iron mineral, silica. Most common mineralized parts: bones and teeth. Finest mineralization = permineralization. Atom by atom replacement: interpret fossilized remains in terms of taphonomic processes and preservation potential. Composition of the creature. The environment where the organism lived and died. Processes affecting the dead organism. Taphonomy: all processes that occur to a creature prior to it becoming a fossil. Necrolysis (decay) + movement of the corpse.
