Bartonium

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system series step ≈ age ( mya )
higher higher higher younger
Paleogene Oligocene Chattium 23.03
⬍
28.1
Rupelium 28.1
⬍
33.9
Eocene Priobonium 33.9
⬍
38
Bartonium 38
⬍
41.3
lutetium 41.3
⬍
47.8
Ypresium 47.8
⬍
56
Paleocene Thanetium 56
⬍
59.2
Seelandium 59.2
⬍
61.6
Danium 61.6
⬍
66
deeper deeper deeper older

The Bartonium (mostly shortened to Barton in German) is the third chronostratigraphic stage of the Eocene (Upper Middle Eocene , Paleogene ) in the history of the earth . The absolute age of the stage ranges ( geochronologically ) from about 41.3 to about 38 million years. It follows the Lutetium and is replaced by the Priabonium .

Naming and history

The name is derived from the place Barton-on-Sea (now a district of New Milton , Hampshire , England ). The Barton Clay Formation , which is open here, is named after this place . The stage and name were suggested by Karl Mayer-Eymar in 1857.

Definition and GSSP

The stage begins with the first appearance of the calcareous nannoplankton species Reticulofenestra reticulata and ends shortly before the first appearance of the calcareous nannoplankton species Chiasmolithus oamaruensis (corresponds to the base of the nannoplankton zone NP18) or before the extinction of Chiasmolithus grandis . The upper limit of the bartonium can be clearly defined by the extinction of the dinoflagellate Rottnestia borussica . A reference profile (GSSP = Global Stratotype Section and Point) for the bartonium has not yet been established.

Magnetostratigraphy

The bartonium begins magnetostratigraphically with Chron C 18r and extends to the lower limit of C 17n.1n . It extends over the entire Chron C 18 .

Biostratigraphy

Planktonic foraminifera

The bartonium comprises the planktonic foraminiferous zones P 12 (upper quarter), the zone P 13 , P 14 , characterized by the taxon Orbulinoides beckmanni , and the lower third of P 15 , the beginning of which is defined by the first appearance ( FAD ) of Globigerinatheka semiinvoluta .

Benthonic large foraminifera

Two benthic Großforaminiferenzonen can be reported in bartonian, SBZ 17 with the taxa Alveolina elongata , Alveolina fragilis , Alveolina fusiform , Discocyclina Pulcra baconica , Nummulites perforatus , Nummulites brogniarti , Nummulites biarritzensis and above SBZ 18 with the taxa biedai Nummulites and Nummulites cyrenaicus .

Calcareous nannoplankton

The calcareous nannoplankton zones in the bartonium are NP 16 (upper third) and NP 17 . NP 17 begins with the extinction ( LAD ) of Chiasmolithus solitus and then extends into the lower Priabonian.

Dinoflagellate cysts

On the basis of dinoflagellates - cysts , the zones are for the bartonian D 10 (upper half) and D 11 expelled. The first appearance of Rhombodinium draco and the disappearance of Areoligera tauloma define the beginning of sub-zone D 10b . D 11 sets in with Rhombodinium porosum , and at the same time Corrudinium incompositum disappears . The first appearance of Wetzeliella simplex defines the beginning of subzone D 11b . The upper limit of the bartonium coincides with the extinction of Rottnestia borussica .

Land mammal biozones

Propalaeotherium died out at the end of the Bartonian

The bartonium is identical to the land mammal stage MP 16 (or Lautricense-Siderolithicum zone ). It has the following bio- zones ( Land Mammal Mega Zones ), separated by continents :

During the Robiacium, the taxa Lophiodon lautricense (defines the beginning of MP 16 ) and Leptolophusstehlini as well as the Palaeotherium castrense and Palaeotherium robiacense appear for the first time . The families Anthracotheriidae , Cainotheriidae and Talpidae also appear . The taxa Lophiodon leptorhynchus , Leptolophus dahlini , Palaeotherium cosetanus , Palaeotherium robiacense and Propalaeotherium (the latter marks the end of the Robiacium) are dying out, as are the families Lophiodontidae and Hyrachyiidae .

At the beginning of the Duchesneum (Duchesneum 1), Mesohippus and the families Amphicyonidae , Anthracotheriidae , Canidae and Rhinocerotidae appear . The first appearance of Ischyromys marks the beginning of Duchesneum 2. At the beginning of Duchesneum 1, Omomys , the family of the Hyrachyiidae , the orders of the Dinocerata and the Taeniodontia disappear . At the end of the Ducheseum, the Nyctitheriidae and the subordination of the Plesiadapiformes die out.

Occurrence

The bartonium occurs in the following sedimentation spaces (sorted from young to old):

literature

  • Felix M. Gradstein, Jim Ogg, Jim Smith, Alan Smith (Eds.): A Geologic timescale 2004 . 3rd edition. Cambridge University Press, Cambridge et al. 2004, ISBN 0-521-78673-8 .
  • Karl Mayer-Eymar : Tableau synchronique des formations tertiaires d'Europe . 3. Edition. Zurich 1857.
  • Hans Murawski, Wilhelm Meyer: Geological dictionary . 10th revised and expanded edition. Enke Verlag, Stuttgart 1998, ISBN 3-432-84100-0 ( Enke paperback ).

Individual evidence

  1. ↑ Curry, D .: Thanetian . In: Pomerol, C. (Ed.): Stratotypes of Paleogene Stages, Mémoire hors série 2 du Bulletin d'Information des Géologues du Bassin de Paris . 1981, p. 255-265 .
  2. ↑ Mayer-Eymar, K .: Attempt of a new classification of the tertiary structures of Europe . In: Negotiations of the Swiss Natural Research Society . tape 42 , 1858, pp. 165-199 .

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