The document discusses fossils and the fossilization process. It defines a fossil as any preserved remains or traces of ancient plants and animals. Fossils form when organisms are rapidly buried and the organic material is replaced or transformed by minerals. There are two main types of fossils - body fossils, which are actual remains, and trace fossils, which are evidence of ancient life like footprints. Certain conditions like hard body parts, rapid burial, and lack of oxygen promote fossilization. Fossils can be preserved in their original form or replaced by minerals through processes like permineralization and carbonization.

1. Fossils & FossilisationFossils & Fossilisation
ByBy
PRAMODA GPRAMODA G
DoS in Earth ScienceDoS in Earth Science
University of MysoreUniversity of Mysore

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What is a fossil?What is a fossil?
A fossil is an impression, cast,
original material or track of
any animal or plant that is
preserved in rock after the
original organic material is
transformed or removed.

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A fossil may be:A fossil may be:
• an original skeleton
or shell;
• a mold or cast;
• material that has
replaced the once
living thing;
• traces such as
footprints or worm
tubes

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What conditions promoteWhat conditions promote
fossilization?fossilization?
• Hard body parts
such as skeletal
bones or
exoskeletons

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What conditions promoteWhat conditions promote
fossilization?fossilization?
• Rapid burial and/or
lack of oxygen

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What are the fossil types?What are the fossil types?
• Body fossils – actual parts of an
organism, unaltered or altered
bones, shells, leaf imprints
• Trace fossils – evidence of life that is
not a body fossil
tracks, burrows, casts

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Body fossilsBody fossils

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Trace FossilsTrace Fossils

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What are the modes of fossilWhat are the modes of fossil
preservation for body fossils?preservation for body fossils?
Unaltered
Original Material - original,
unaltered material from the
living organism
unaltered bone or shell
Encrustations or
entombments –
material is trapped inside
coating such as amber

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What are the modes of fossilWhat are the modes of fossil
preservation for body fossils?preservation for body fossils?
Unaltered
Mummification - quickly
dried material
Refrigeration –
material is trapped
inside ice and tissue is
preserved

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What are the modes of fossilWhat are the modes of fossil
preservation?preservation?
• Altered
Permineralization –
pores in tissue are
filled by minerals
Replacement –
replacement of
tissue with minerals

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What are the modes of fossilWhat are the modes of fossil
preservation for body fossils?preservation for body fossils?
• Altered
Carbonization – tissue
material is
decomposed or
reduced to a film of
carbon

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More on trace fossilsMore on trace fossils
• Mold – reproduction
of the inside or
outside surface of a
living thing
• Cast – duplicate of
the original
organism; usually
formed by
replacement of
inside of living thing

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More on trace fossilsMore on trace fossils
• Burrows or borings –
Spaces dug out by
living things and
preserved as is or
filled in

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More on trace fossilsMore on trace fossils
• Gastroliths – smooth
stones from
abdominal cavity of
dinosaurs
• Coprolites –
fossilized
excrement; usually
preserved by
replacement

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More on trace fossilsMore on trace fossils
• Tracks – impressions
of passage of living
things