| System (period) | Series (epoch) | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Cretaceous | Lower | Berriasian | ~145 | |
| Jurassic | Upper (Late) | Tithonian | 149.2±0.7 | |
| Kimmeridgian |  154.8±0.8
| |||
| Oxfordian | 161.5±1.0 | |||
| Middle | Callovian | 165.3±1.1 | ||
| Bathonian | 168.2±1.2
| |||
| Bajocian | 170.9±0.8
| |||
| Aalenian | 174.7±0.8
| |||
| Lower (Early) | Toarcian | 184.2±0.3
| ||
| Pliensbachian | 192.9±0.3
| |||
| Sinemurian | 199.5±0.3
| |||
| Hettangian | 201.4±0.2
| |||
| Triassic | Upper | Rhaetian | older | |
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] | ||||
The Pliensbachian is a third stage of the Lower Jurassic series, corresponding to the Pliensbachian age of the Early Jurassic epoch. It lasted from approximately 192.9 Ma to around 184.2 Ma (million years ago). It is preceded by the Sinemurian and is followed by the Toarcian.
Definition[]
The GSSP of the Pliensbachian stage was ratified in 2005. The lower boundary is fixed in Wine Haven, Yorkshire Coast, England, and related to the first appearance of the ammonite association of Bifericeras donovani and Apoderoceras sp.[2]
Pliensbachian life[]
The Tethys Ocean, separating Laurasia and Gondwana, was inhabited by numerous ammonites like Uptonia and Dayiceras, whose elegant shells were found in the Lower Pliensbachian sediments of Southern Vendée, France. Squid-kike belemnites were also numerous. Hastites, Passaloteuthis and Angeloteuthis lived in the sea that covered the territory of today's Gloucestershire, United Kingdom. Cartilaginous hybodontiform (Hybodus, Lissodus) and synechodontiform (Paraorthacodus, Palidiplospinax) fish were common. Ichthyosaurs like Leptonectes fed on small fish and cephalopods. The diversity of plesiosaurs continued to increase. Cryonectes is known from the Upper Pliensbachian of Calcaire à Bélemnites Formation, France, and Arminisaurus was found in the Upper Pliensbachian of the Amaltheenton Formation in northwestern Germany. As sea levels rose, various land animals adapted to life in the water. Turnersuchus, one of the most basal thalattosuchians, is known from the Pliensbachian of the United Kingdom.
On land, dinosaur evolution continued. Carnivores like Dilophosaurus hunted sauropodomorphs. Primitive forms like Sarahsaurus and Massospondylus still existed in the Pliensbachian, although sauropods like Barapasaurus gradually replaced them. Pterosaurs like Dimorphodon soared in the skies.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Mesozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=35.