Biozone

The concept of a biozone was first established by the 19th century paleontologist Albert Oppel, who characterized rock strata by the species of the fossilized animals found in them, which he called zone fossils. Oppel's biozonation was mainly based on Jurassic ammonites he found throughout Europe, which he used to classify the period into 33 zones (now 60). Alcide d'Orbigny would further reinforce the concept in his Prodrome de Paléontologie Stratigraphique, in which he established comparisons between geological stages and their biostratigraphy. ==Types of biozone==

The International Commission on Stratigraphy defines the following types of biozones: Lineage zones are named for the specific taxon they represent. Assemblage zones An assemblage zone is a biozone defined by three or more different taxa, which may or may not be related. The boundaries of an assemblage zone are defined by the typical, specified fossil assemblage's occurrence: this can include the appearance, but also the disappearance of certain taxa. Because an abundance zone requires a statistically high proportion of a particular taxon, the only way to define them is to trace the abundance of the taxon through time. As local environmental factors influence abundance, this can be an unreliable way of defining a biozone. Abundance zones are named after the taxon that is the most abundant within its range. == Zone fossils used for biozonation ==

onwards). A great variety of species can be used in establishing biozonation. Graptolites and ammonites are some of the most useful as zone fossils, as they preserve well and often have relatively short biozones. Fossils of pigs and cannabis can be used for biozonation of Quaternary rocks as they were used by hominids. ==See also==