Fossil Record

Abstract

Fossils are the remains of plants and animals that once lived. Quality of preservation ranges from complete to traces of hard parts only, and it is important to consider how this incompleteness affects understanding of past life.

Keywords: fossils; preservation; taphonomy; quality; completeness

Figure 1.

The relative rates of decay (vertical axis) and mineralization (horizontal axis) determine the kinds of tissues that may be preserved. At minimum decay rate and with very early mineralization, highly labile muscle tissues may be preserved. When decay has gone to a maximum, and when mineralization occurs late, all that is left are the nonorganic tissues such as shells.

Figure 2.

The conditions for exceptional preservation. (a) Rate of burial and organic content are key controls on the nature of mineralization of organic matter in fossils. Pyritization (high rate of burial; low organic content) may preserve entirely soft‐bodied worms, as in an example of the starfish Loriolaster (b) from the Early Devonian Hunsrückschiefer of Germany. Phosphatization (low rate of burial; high organic content) may preserve feathers as in (c), an unidentified bird from the Eocene of Germany. Soft parts may be preserved in carbonate (high rate of burial; high organic content), such as the limbs and antennae of a shrimp (d), from the Carboniferous of Scotland. If decay never starts, small animals may be preserved organically and without loss of material, as in a centipede in amber from the Early Tertiary of the Baltic region (e).

Figure 3.

Processes of breakage and diagenesis of fossils. Dead organisms may be disarticulated (a) or fragmented (b) by scavenging or transport, abraded (c) by physical movement, bioeroded (d) by borers, or corroded and dissolved (e) by solutions in the sediment. After burial, specimens may be flattened (f) by the weight of sediment above, or various forms of chemical diagenesis, such as the replacement of aragonite by calcite (g) may take place.

close

Further Reading

Benton MJ and Harper DAT (1997) Basic Palaeontology. London: Addison‐Wesley Longman.

Briggs DEG (1991) Extraordinary fossils. American Scientist 79: 130–141.

Briggs DEG and Crowther PR (2001) Palaeobiology; A Synthesis II. Oxford: Blackwell.

Fortey RA (1999) Life: a Natural History of the First Four Billion Years of Life on Earth. New York: Vintage.

Fortey RA (2002) Fossils: the Key to the Past. 3rd edn. Washington: Smithsonian; London: Natural History Museum.

Gould SJ (ed.) (1993) The Book of Life. London: Ebury Hutchinson.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Benton, Michael J(Sep 2005) Fossil Record. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0004118]