| 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 Toarcian is a fourth and upper stage of the Lower Jurassic series, corresponding to the Toarcian age of the Early Jurassic epoch. It lasted from approximately 184.2 Ma to around 174.7 Ma (million years ago). It is preceded by the Pliensbachian and is followed by the Aalenian of the Middle Jurassic.
Definition[]
The GSSP of the Toarcian stage was ratified in 2014. The lower boundary is fixed in Ponta do Trovao, Portugal, and related to the first appearance of the ammonites Dactylioceras (Eodactylioceras) simplex, D. (E.) pseudocommune and D. (E.) polymorphum.[2]
Toarcian life[]
The diversity of marine life increased. Numerous ammonites of the genera Canavaria, Dactylioceras, Lytoceras, Neolioceratoides and Praepolyplectus are known from the Toarcian Tagoudite Formation of central High Atlas, Morocco. During Toarcian, this area was located near the north part of Gondwana. Small fish such as Leptolepis and Lepidotes frolicked in the seas that covered the territory of Europe, near Laurasia. 1 meter long Pachycormus hunted cephalopods and smaller fish. Ichthyosaurs fed on surface and deep-sea small animals. Stenopterygius, a medium-sized ichthyosaur, is known from the Toarcian of Europe. Other marine reptiles of the time include plesiosauroids like Lusonectes and thalattosuchians like Steneosaurus and Teleosaurus.
The largest land herbivores were sauropods like Patagosaurus. Theropods like Piatnitzkysaurus were hunted them.
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.