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The Mammal Neogene zones or MN zones are system of biostratigraphic zones in the stratigraphic record used to correlate mammal-bearing fossil localities of the Neogene period of Europe.
Short title: Birth to 36 months: Boys, Length-for-age and Weight-for-age percentiles: Image title: CDC Growth Charts: United States: Author: NCHS: Keywords
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them. [1] The primary objective of biostratigraphy is correlation , demonstrating that a particular horizon in one geological section represents the same period of time as another ...
In biostratigraphy, biostratigraphic units or biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa, as opposed to a lithostratigraphic unit which is defined by the lithological properties of the surrounding rock. A biostratigraphic unit is defined by the zone fossils it contains. These ...
[17]: 10 They have also attempted to convert some of the intervals, including the Wasatchian age/stage and Clarkforkian age/stage, into biostratigraphic units. [ 6 ] : 16 However, the fossil record remains discontinuous even in North America, and Woodburne speculates that "mammal age correlations provide results that are satisfactory to their ...
The North American land-mammal-age system was formalized in 1941 as a series of provincial land-mammal ages. [2] The system was the standard for correlations in the terrestrial Cenozoic record of North America and was the source for similar time scales dealing with other continents. The system was revised into a formal chronostratigraphic system.
Stages are primarily defined by a consistent set of fossils (biostratigraphy) or a consistent magnetic polarity (see paleomagnetism) in the rock. Usually one or more index fossils that are common, found worldwide, easily recognized, and limited to a single, or at most a few, stages are used to define the stage's bottom.
By combining multiple geochronological (and biostratigraphic) indicators the precision of the recovered age can be improved. Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages.