| System (period) | Series | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Neogene | Miocene | Aquitanian | 23.03 | |
| Paleogene | Oligocene | Chattian |  27.82
| |
| Rupelian | 33.9
| |||
| Eocene | Priabonian | 37.71
| ||
| Bartonian | 41.2 | |||
| Lutetian | 47.8
| |||
| Ypresian | 56.0
| |||
| Paleocene | Thanetian | 59.2
| ||
| Selandian | 61.6
| |||
| Danian | 66.0
| |||
| Cretaceous | Upper | Maastrichtian | older | |
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] | ||||
Wyoming rock wich with the Iridium geochemical anomaly (light intermediate claystone layer), that indicates the base of the Paleocene series.
The Paleocene, "early dawn of the recent" is a geologic epoch that lasted from 66 Ma to 56.0 Ma (million years ago), corresponding to the Paleocene series in stratigraphy. It is the first epoch of the Paleogene Period in the modern Cenozoic era. As with most other older geologic periods, the strata that define the epoch's beginning and end are well identified but the exact date of the end is uncertain.
The Paleocene epoch immediately followed the mass extinction event at the end of the Cretaceous, known as the K-T boundary (Cretaceous - Tertiary), which marks the demise of the lots of reptiles. The die-off of the non-avian dinosaurs left unfilled ecological niches worldwide, and the name "Paleocene" comes from Greek and refers to the "old(er)" (παλαιός, palaios) – "new" (καινός, kainos) fauna that arose during the epoch, before modern mammalian orders emerged in the Eocene.
Definition[]
The GSSP of the Paleocene series as well as the Danian stage, Paleogene system and the whole Cenozoic erathem was ratified in 1991. The lower boundary is fixed in Oued Djerfane, Tunisia, and related to the reddish layer at the base of the dark boundary clay, associated with the Iridium geochemical anomaly and a major extinction horizon.[2]
Subdivisions[]
The Paleocene series is broken into three stages. These stages from upper to lower are:
In geochronology, all stages correspond to the same ages.
Paleogeography[]
The North Atlantic was much narrower and expanded throughout the epoch as North America and Greenland moved away from Europe. The Western Interior Sea retreated, aided by rising Rocky Mountains and falling sea levels, and the continents of Laramidia and Appalachia merged into a single North American continent. The Isthmus of Panama has not yet appeared, and warm sea waters flowed between North and South America. Large areas of northern Africa and western Asia were still covered by the Tethys Ocean. Australia was located much further south than it is today.
Paleocene life[]
The mass K-P extinction led to the complete disappearance of many groups of sauropsids, such as plesiosaurs, mosasaurs and pterosaurs. Dinosaurs, with the exception of birds, also became extinct. Ammonites still existed for some time after the extinction, but by the end of the epoch they gone extinct too. With the end of the cataclysms, the rise of mammals began. Among them, large herbivorous and carnivorous forms quickly appeared, many of which, however, were too primitive to be attributed to any modern order.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Cenozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=2.