European land mammal age

ELMMZ is the acronym for " European Land Mammal Mega - Zones" and in the earth's history means the biostratigraphic subdivision of mainly terrestrial sediments of the Cenozoic in Europe with the help of land mammal remains. The division into bio- zones was independently Neogene and Paleogene. Therefore, a distinction in ELMMZ ( Neogen ) and ELMMZ ( Paleogene ) is necessary. The term ELMMZ was proposed in 1999 to replace the old term ELMA ( " European Land Mammal Ages" ), because " Age" ( = age) in the stratigraphic terminology is a term used in geochronology, while the biozones are purely biostratigraphically defined.

Problems of dating

The relative dating of mainly deposited on the land sediments of the Cenozoic era is difficult, because the fossils used to define the chronostratigraphic stages are exclusively marine organisms that do not occur naturally in continental sediments. Occasional marine incursions ( transgressions ) can, documented by marine fossils, give a first indication for the relative dating of the sediments. However, an even finer subdivision of such sediments may be carried out by fairly frequent fossils, such as land mammals. Remains of small mammals can be quite common in terrestrial deposits of the Cenozoic. Be found not only bones, but especially teeth against bone have a better preservation potential.

History

Trying to terrestrial deposits (mainly Neogene ) to be broken down by mammalian residues has a long tradition. 1865 already defined Lorenzo Pareto, the Villafranchian. Pierre My 1975 summed up the previous results together and proposed a subdivision of the Neogene in 17 zones before that are designated by the letters MN, where MN for " Mammals Neogene " is.

Definition of zones

The zones are each defined by the first appearance ("First appearance date" = FAD) of specific genera and / or species. A distinction is made between small and large mammals. These zones are purely biostratigraphically defined.

Subdivision

The terrestrial Neogene in Europe is divided into seven regional " levels" and 17 zones. While the zones are biostratigraphically defined, the steps are in the current literature, a mixture of regional, biostratigraphic, chronostratigraphic and geochronological units. Steininger (1999) recommends a predominantly biostratigraphic definition of these stages (from top to bottom):

  • Villafranchian ( includes MN zones 16, 17 and MNQ1 ) (ca. 3.4 to 1.1 Ma)
  • Ruscinium ( MN zones 14 and 15) ( approximately 4.7 to 3.4 million years)
  • Turolium ( MN zones 11-13 ) (about 9 to 4.7 Ma)
  • Vallesium (zones MN 9 and 10) (approx. 11.2 to 9 Ma)
  • Astaracium ( MN zones 6 and 7/ 8) (about 15.2 to 11.2 Ma)
  • Orleanium ( MN zones 3-5 ) (about 20 to 15.2 million years)
  • Agenium ( MN zones 1 and 2 ) (ca. 23-20 Ma)

The boundaries of the zones and the levels are z.T. still very uncertain and are still discussed controversially. In parallel, the level Aragonium ( 18 to 11.2 Ma) is used often.

Aquitanian (stage) Langhian Serravallian Tortonian Messinian Agenian Vallesian Turolian Gelasian Orleanian Astaracian Ruscinian Mya (unit) History of the Earth Eucladoceros Beaver Cricetulodon Machairodus Gomphotherium
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