Turonium

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system series step ≈ age ( mya )
higher higher higher younger
chalk Upper Chalk Maastrichtium 66
⬍
72
Campanium 72
⬍
83.6
Santonium 83.6
⬍
86.3
Coniacium 86.3
⬍
89.7
Turonium 89.7
⬍
93.9
Cenomanium 93.9
⬍
100.5
Lower Cretaceous Albium 100.5
⬍
112.9
Aptium 112.9
⬍
126.3
Barremium 126.3
⬍
130.7
Skin rivium 130.7
⬍
133.9
Valanginium 133.9
⬍
139.3
Berriasium 139.3
⬍
145
deeper deeper deeper older

The Turonium (in German usage often shortened to Turon ) is a chronostratigraphic level of the Upper Cretaceous in geological history . The turonian began geochronologically about 93.9 million years ago and ended about 89.7 million years ago. The Turonium followed the Cenomanium , followed by the Coniacium .

At the beginning of the Turonium an oceanic anoxic event took place, which was named after its first descriptor Livello Bonarelli , eng .: "Cenomanian Turonian Boundary Event".

Naming and history

The original eponymous type locality of this level is in the French landscape of Touraine near the French city of Tours ( Département Indre-et-Loire , France). The lat. Name of the landscape is Turonia . The stage and its name were proposed by Alcide Dessalines d'Orbigny in 1842.

Definition and GSSP

The beginning of the stage is defined by the first onset of the ammonite species Watinoceras devonense . The border to the Coniacium , the next stage, through the first appearance of the Inoceramen species Cremnoceramus rotundatus . The GSSP (Global Type Locality and Type Profile) is located in the Rock Canyon Antique Line, west of Pueblo , Colorado , USA (coordinates: 38 ° 16 '56 "N, 104 ° 43' 39" W).

Breakdown

The Turon can be divided into the lower, middle and upper turon levels.

The following biostratigraphic ammonite zones are excreted for the Tethys area :

In the Oberturon:

In the middle turon:

In the underturon:

Fossils

Important key fossils of the Turon are the following Inoceramen ( mussels ): Inoceramus schloenbachi , Inoceramus lamarcki and Inoceramus labiatus .

literature

  • Felix M. Gradstein, James G. Ogg, Alan G. Smith (Eds.): A Geologic Time Scale 2004 . Cambridge University Press, Cambridge (UK) 2005, ISBN 0-521-78673-8 .
  • Hans Murawski, Wilhelm Meyer: Geological dictionary. 10., rework. u. exp. Edition. Enke Verlag, Stuttgart 1998, ISBN 3-432-84100-0 .
  • W. Jim Kennedy, Irek Walaszczyk, William A. Cobban: The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, USA In: Episodes. 28 (2), Beijing 2005, pp. 93-104.

Web links