The Campanian (often shortened as Germans Campan ) is in Earth's history, a chronostratigraphic stage of the Upper Cretaceous. She began geochronological about 83.6 million years ago and lasted until about 72 million years. The Campanian following the Santonian and is detached from the Maastrichtian.
Naming and history
Henri Coquand led the stage and name 1857 in the scientific literature, as type locality served him " La Grande Champagne ", a ridge in Aubeterre -sur -Dronne in the Charente region of France. His former type locality has now, however, proved to be Maastrichtian.
Definition and GSSP
The lower limit is defined by the extinction of the crinoid type Marsupites testudinarius, the upper limit by the first appearance of ammonite species Pachydiscus neubergicus. A GSSP (global type locality and type profile ) has not yet been ratified concluded.
The Campanian can be divided into sub- steps lower, middle and Obercampanium.
In Tethysbereich six ammonite zones are in the Campanian currently retired ( from young to old):
- Nostoceras hyatti
- Didymoceras chayennense
- Bostrychoceras polyplocum
- Hoplitoplacenticeras marroti / Hoplitoplacenticeras vari
- Delawarella delawarensis
- Placenticeras bidorsatum
In the Campanian was a big jump in the biodiversity of the dinosaurs. From the beginning of the Campanian found for example in North America four genera the number of different dinosaur genera of biodiversity rose on this continent until the end of the Campanian to 48 One speaks in analogy to the Cambrian explosion of biodiversity of animals in the Cambrian of the " Campanian explosion" of the dinosaurs. But it is not yet clearly established how much the acceptance of such radiation is due to the Fund position, that is, that from the early Campanian either less fossil evidence of dinosaurs exist or they have not been found. Anyway, should have offered his spread over almost the entire globe hot climate and the extensive shallow seas excellent ecological basis for the dissemination of the dinosaurs and other animals the Campanian. It is clear that during the subsequent age, Maastrichtian, the number of genera of dinosaurs decreased by at least 30 % until they became extinct in a relatively short period at the end of the Cretaceous period.