4.2.7 Chronozone (Kronosone)
4.2.7.1 Chronozone is a non-hierarchical, formal or informal chronostratigraphical unit (Table 2), which nevertheless usually has a low rank. A chronozone is defined on the basis of a biostratigraphical, lithostratigraphical or magnetostratigraphical unit. The basis for the definition should be made apparent when the chronozone is designated (e.g. "biochronozone", "lithochronozone" or "polarity-chronozone") (Section 4.5.2). The boundaries of a chronozone can be defined independently of those of ranked units in the reference succession.
Informal biochronozones and lithochronozones based on key horizons or marker beds often have great practical importance when investigations and interpretations of local sedimentary basins are being carried out.
The division of time corresponding to a chronozone is a chron (kron).
4.2.7.2 Names of chronozones -- Formal and informal names given to chronozones are constructed according to the physical definition of the chronozone. A chronozone that is defined on the basis of a biozone carries the biological name of the biozone, e.g. "Exus albus chronozone" ("Exus albus kronosone"). Corresponding examples for lithochronozones and polarity chronozones are "Woodbend Lithochronozone" ("woodbend litokronosone") and "Gilbert Reversed-Polarity Chronozone" ("gilbert reverspolaritetskronosone"), respectively.
