Fossil





Fossils are the mineralized remains of animals or plants or other artifacts
such as footprints. The totality of fossils and their placement in rock
formations and sedimentary layers is known as the fossil record.

Fossilization is a rare occurrence, because natural materials tend to be
recycled. In order for an organism to be fossilized, the remains need to be
covered by sediment as soon as possible. There are different types of
fossils, and fossilization processes:

Permineralization

This process consists of literally turning an organism into stone. The
organism gets covered by sediment soon after death, or after the initial
decaying process. The degree in which the remains are decayed when covered,
determines the later details of the fossil. Some fossils only consist of
skeletal remains or teeth; other fossils contain traces of skin, feathers or
even soft tissues. Once covered with sediment, these layers slowly compact
to rock, after which the chemicals in the remains are slowly replaced with
hard minerals.

Mould, cast and trace fossils

If percolating water dissolves the remains of an organism, and thereby
leaves a hole, this is called a mould fossil. If this hole is filled with
more minerals, it is called a cast fossil. If the burial of the organism was
rapid, then chances are that even impressions of soft tissues remain. Trace
fossils are the remains of track ways, burrows, footprints, eggs and shells,
nests and droppings. The latter, called coprolites can give insight in the
feeding behavior of animals, and can therefore be of great importance.

Resin fossils

Smaller animals, insects, spiders and small lizards, can be trapped in resin
(amber), which oozes from trees. These fossils can be found in sand- or
mudstones.

Pseudofossils

These are regular patterns in rocks, which are produced by natural occurring
processes. They can easily be mistaken for real fossils. These fossils can
be formed by naturally formed fissures in the rock that get filled up by
percolating minerals. Other types of pseudofossils are kidney ore, round
shapes in iron ore, and 'moss agates', which look like plant leaves.

Living fossils

A term used for any living species which closely resembles a species known
from fossils, i.e., as if the fossil had "come to life". This may sometimes
be a species known only from fossils until living representatives were
discovered (the most famous example of this is the coelacanth fish
(Latimeria chalumnae)). Other "living fossils" are the nut clams (Ennucula
superba), Lingula anatina, an inarticulate brachiopod, and the horseshoe
crab (Limulus polyphemus).

Additional information see Fossils and the geological timescale

The study of fossils is called paleontology.

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Fossil is also the tradename of the manufacturer of a popular line of
watches and jewelry in the United States.
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FOSSIL is the name of a protocol for serial communications.