| System (period) | Series (epoch) | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Paleogene | Paleocene | Danian | 66,0 | |
| Cretaceous | Upper (Late) | Maastrichtian |  72.1±0.2
| |
| Campanian | 83.6±0.2
| |||
| Santonian | 86.3±0.5
| |||
| Coniacian | 89.8±0.3
| |||
| Turonian | 93.9
| |||
| Cenomanian | 100.5
| |||
| Lower (Early) | Albian | ~113.0
| ||
| Aptian | ~121.4 | |||
| Barremian | 125.77* | |||
| Hauterivian | ~132.6
| |||
| Valanginian | ~139.8 | |||
| Berriasian | ~145.0 | |||
| Jurassic | Upper | Tithonian | older | |
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] *A golden spike is seen in chart but not ratified yet. | ||||
Lithographic limestone from the Gerofit Formation (Turonian) north ofMakhtesh Ramon, southern Israel; a variety of Jerusalem stone (meleke)
The Turonian is a second stage of the Upper Cretaceous series, corresponding to the Turonian age of the Late Cretaceous epoch. It lasted from approximately 93.9 Ma to around 89.8 Ma (million years ago). It is preceded by the Cenomanian and is followed by the Coniacian.
At the beginning of the Turonian ananoxic event took place which is called the Cenomanian-Turonian boundary event or the "Bonarelli Event".
Definition[]
The GSSP of the Turonian stage was ratified in 2003. The lower boundary is fixed in the base of Bed 86 of the Bridge Creek Limestone Member of the section in Colorado, USA, and related to the first appearance of the ammonite Watinoceras devonense.[2]
Turonian life[]
Megacephalosaurus captured a mosasaur
Numerous ammonites continued to inhabit seas around the world. Turonian genera include Yokoyamaoceras, Neocrioceras, Gaudryceras, Collignoniceras and Subprionocyclus. Cartilaginous fish were varied and numerous. Cretodus crassidens, a huge lamniform shark, existed in the Turonian. Significant changes were occurring polycotylids (such as Trinacromerum) were still common. Pliosaurids like Brachauchenius too were close to extinction. Megacephalosaurus, one of the last huge pliosaurids, existed in the Turonian. In parallel with the disappearance of pliosaurids, another group of reptiles, mosasaurs, gradually spread into the seas. Early members of the Turonian include Platecarpus-like specimens from Brazil and Australia.
Fresh waters were already inhabited by a huge number of amphibians, related to modern frogs and toads. Salientians like Gobiates, Procerobatrachus, Saevesoederberghia and Aralobatrachus were found in the Turonian strata of Bissekty Formation in Uzbekistan. Many ecological niches remained occupied by reptiles. Turtles like Khunnuchelys, Shachemys, Adocus, and the possible species of the modern genus Trionyx lived in the Turonian rivers alongside with the numerous crocodylomorphs like Zhyrasuchus, Tadzhikosuchus and Zholsuchus.
A wide variety of dinosaurs lived on land. Titanic sauropods, including Argentinosaurus and Futalognkosaurus, roamed the southern continents, and huge theropods like Mapusaurus and Megaraptor hunted them. Ornithopods spread widely, their Turonian genera include Cionodon, Levnesovia and Jeyawati. By this time, new forms arose among dinosaurs. The first ceratopsoids probably appeared in this age. The earliest were Zuniceratops and Turanoceratops from the Turonian of New Mexico, USA, and Uzbekistan respectively. Therizinosaurids like Nothronychus and tyrannosauroids like Alectrosaurus have spread to the northern hemisphere. Dromaeosaurids like Itemirus reached large numbers as well as birds, their close relatives. Such avian dinosaurs as Explorornis, Sazavis, Lenesornis and Ichthyornis flew well and were probably beginning to compete with pterosaurs such as Azhdarcho in the skies. The number of ground lizards increased. Turonian Buckantaus was a distant relative of modern iguanas.
The number of mammals continued to increase. In the Turonian strata of Uzbekistan, various mammals like Kulbeckia, Parazhelestes, Aspanlestes, Paranyctoides and Sulestes have been found.
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.