Priabonian
The Priabonium (usually shortened in the German language to Priabon ) the uppermost stratigraphic stage of the Eocene is in Earth's history ( Paleogene ). In absolute terms, expressed ( geochronological ) corresponds to the period of about 38 to about 33.9 million years. The stage following the Bartonium and is detached from the Rupelium, the lowest level of the Oligocene.
- 6.1 Literature
- 6.2 Notes and references
Naming and history
The stage is named after the locality Priabona, which belongs to the municipality of Monte di Malo in the province of Vicenza (Italy). Stage and name were proposed by the two French geologists Ernest Munier - Chalmas and Albert de Lapparent 1893.
Definition and GSSP
The level lower limit can be defined by the first occurrence of the dinoflagellate Rhombodinium perforatum and with the beginning of Chron C 17n.3n identical, slightly above the calcareous nannoplankton occurs Style Chiasmolithus oamaruensis ( corresponding to the base of nannoplankton zone NP18 ) for the first time on. The end of the stage is defined by the extinction of the foraminiferal genus Hantkenina and the taxon Turborotalia cerroazulensis cunialensis. A reference profile ( GSSP = Global Stratotype Section and Point) for the Priabonium has not yet been determined, as a candidate but lends itself to the pelagic profile in the Valle della Contessa (central Italy).
Magnetostratigraphy
As already mentioned the Priabonium magnetostratigraphisch begins with Chron C 17n.1n. The stage then involves the Chron C 16, C 15 and C 13 r (more precisely to C 13r.86 ).
Biostratigraphy
Planktonic foraminifera
The Priabonium contains the planktonic Foraminiferenzonen P 15 (upper two-thirds ), P 16 and P 17, P 16 With enters the taxon Turborotalia cerroazulensis cunialensis first time (FAD ); their extinction ( LAD) marks the upper limit of P 17 and the end of Priabons. The taxon Globigerinatheka semiinvoluta had appeared with P 15 before the start of Priabons.
Calcareous nannoplankton
The calcareous nannoplankton is represented by the zones NP 17 (top section), NP 18, NP 20 and NP 21 19/NP (lower third ). The first appearances of Chiasmolithus oamaruensis defines the beginning of NP 18, Isthmolithus recurvus the start of NP 19 Discoaster barbadiensis disappears at the end of NP 20
Dinoflagellates
The Priabonium covers most of the cysts Zone D 12, whose beginning is marked by Rhombodinium perforatum and is identical to the lower limit of Priabons. Dinoflagellatenzone the D 12 is divided into three zones (D 12a, D 12b D 12c). D 12b starts with the first publication of Talassisphora fenestrata, D 12c with Talassisphora reticulata. Heteraulacacysta porosa disappears at the end of D 12a and Glaphyrocysta semitecta at the end of D 12b. The extinction of Areosphaeridium michoudii is identical with the beginning of Chron C15.
Land mammal biozones
This includes Priabonium, separated by specific continents, following land mammal biozones (Land Mammal Mega Zones):
- Europe ( ELMMZ ): Headonium.
It disappear families Xiphodontidae and Amphimerycidae and Propalaeotherium taxa ( at the beginning of Priabons ) Quercygale, Isoptychus euzetensis and Palaeotherien Lophiotherium and the three Palaeotherium species P. villerealense and P. curtum and P. medium. First come the families of the Cricetidae and Castoridae on and the taxa Isoptychus euzetensis and Entelodon and four types of Palaeotherium: P. magnum, P. villerealense, P. and P. curtum medium.
- North America ( NALMMZ ): Chadronium, divided into three stages, Chadronium 1, Chadronium 2 and 3 Chadronium
The families Nyctitheriidae, Cylindrodontidae, Oromerycidae ( towards the end of Priabons ) and the Plesiadapiformes ( at the beginning of Priabons ) dying out. The families of the Ursidae ( Parictis ) and the Entelodontidae ( beginning of Ch 1), the Nimravidae and the taxon Merycoidodon first appear ( beginning of Ch 2) and the Cricetidae and the Mustelidae ( beginning of Ch 3).
- South America ( SALMMZ ): Barrancium and Mustersum.
- Asia ( ALMMZ ): Ulangochuium and Ergilium.
Occurrence
In addition to the eponymous deposits in northern Italy ( deep marine area), the Priabonium occurs in the following Sedimentationsräumen on ( both ordered from the hanging wall to the footwall ):
- Hampshire Basin, southern England: Bouldnor lineup, Bembridge Limestone Formation and Headon Hill Formation.
- Belgian Basin: Wemmel group with Assche Formation ( clays ) and Wemmel Formation ( sands) and in the footwall the Lédien with the Lede Formation ( sands).
- Paris Basin: divided into Ludien in the hanging wall with the Gypses du Montmartre and as the underlying Auversien with the Calcaire de Saint Ouen and the Sables de Beauchamp.
- Lower Rhine Valley: Ratheim layers.
- North German lowlands: Beautiful forest formation.
- Oberrheintal: Pechelbronn group, including dolomite, marl zone and the Melanienkalk.
- North Alpine Molassevortiefe: Lithothamnienkalk and below the base of sandstone, both linked with the Ampfing sandstone.
- Vienna Basin: schlier (Lowest section).
- Helvetic: Globigerina marl. In Switzerland, roof slate group and Altdorfer sandstone, Taveyannazsandstein, Stadschiefer and Hohgant. In Upper Bavaria, the Latvians and the floor granite marble takes the place of the Swiss Stadschiefers and Hohgantsandsteins.
- Unterinntal: Häringer layers.
- Upper Italy: Priabonaschichten, Promina layers and Roncà layers.
- Egypt: Mokattam formation.
- India: Tapti lineup.