Fossils
Window to the past
Impressions
What are impressions ?
Impressions are two dimensional imprints of an organism that doesn't
contain any organic material. An impression is a clue left of the organism's
biological activity, they can be formed
while the organism was moving or any other biological activity. Some examples
of impressions are the trace fossils such as footprints, traces, remains
of tunnels left by burrowing organisms, fossilized excrement's, and the
holes made in shells by parasites. Impressions usually occur in fine-grained
sediment such as clay or silt. One of the biggest sights where impressions
of plant remains have been found are in clay pits, and especially in Puryear,
Tenessee where there are remnants of Eocene plants.
What do impressions tell us ?
Impressions offer valuable information and are effective in the reconstruction
of prehistoric environments. Impressions left by amphibians and reptiles
in Paleozoic rocks has shown the way in which these ancient animals, otherwise
known only by their skeleton structure, moved. Impressions left by the
fearsome dinosaurs have allowed us to determine the environment in which
these enormous reptiles lived. Through impressions, paleontologist are
able to draw upon relationships that existed among various organisms in
certain geographical areas.
However, impressions do present some problems to paleontologists in
the fact that they are often difficult to encode, especially concerning
marine organisms. Many times it is difficult to establish what kind of
invertebrate may belong to a specific impression or certain borings in
rocks.
Index
Amber || Casts & Molds
|| Compactions || Compressions
|| Coprolites & Gastroliths
Drying & Dessication || Freezing
|| Impressions || Molecular
Fossils || Permineralization
Reference || Trace
Fossils || Wax & Asphalt
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