Quaternary

The Quaternary is the youngest period of Earth's history including the Holocene and thus the present. The science that deals with the study of the Quaternary is the Quaternary research.

In historical geology, the Quaternary represents a chronostratigraphic system or geochronological period. It began about 2.6 million years ago and continues to the present day. It encompasses the entire Quaternary Ice Age, during which the hominization of modern humans also took place.

After Antarctica had already been glaciated for a long time, glaciations also occurred in the Northern Hemisphere at the beginning of the Gelasian. The beginning of this glaciation period, which continues to this day with an alternation of cold periods and warm periods, is regarded by geologists as a suitable demarcation of the Quaternary from the preceding period of the Neogene. Previously, the boundary between "Tertiary" and Quaternary had long been drawn 1.806 million years ago. Because of the relatively short duration of the Quaternary by geological standards and its different development in the marine and continental realms, a conclusive demarcation from the preceding period was not possible, or only with difficulty; the boundary with the Tertiary was disputed. This even led to the deletion of the terms Tertiary and Quaternary from the geological time scale in 2004.

In 2005, the efforts of the various Quaternary geology associations were successful in at least restoring the term Quaternary to a place in stratigraphy. However, it took several more years of discussion before it was decided to reintroduce the Quaternary into the Geologic Time Scale. The Quaternary now follows the Paleogene and Neogene periods within the Cenozoic (Earth's New Era). In this sense, it is defined by the chronostratigraphic stage of the Gelasian as its lowest unit, beginning 2.588 million years before the present. This provided a better demarcation from the periods preceding it. The entire period of the Earth's glacial climatic fluctuations could now be subsumed under the term Quaternary.

At the same time, the Pleistocene, the older epoch of the Quaternary, was also extended by the Gelasian, and thus the Pliocene, the youngest epoch of the Neogene, was shortened by the same period. The Pleistocene is followed within the Quaternary by the Holocene, climatically a warm period within the glacial age, encompassing the most recent 11,700 years to the present. There is discussion about calling the most recent period with a clear human influence the "Anthropocene".

Subdivision

The Quaternary is subdivided as follows:

• System: Quaternary (2.588-0 mya)
• Series: Pleistocene (2.588-0.012 mya)
• Stage: Gelasium (2.588-1.806 mya)
• Stage: Old Pleistocene (Calabrium) (1.806-0.781 mya)
• Stage: Middle Pleistocene (Ionian) (0.781-0.126 mya)
• Stage: Late Pleistocene (Tarantium) (0.126-0.012 mya)
• Series: Holocene (0.012-0 mya)
• Stage: Preboreal (9610 - 8690 B.C. )
• Stage: Boreal (8610 - 7270 B.C. )
• Stage: Atlantic (7270 - 4500 B.C. )
• Stage: Subboreal (4500 - 800 B.C. )
• Stage: Sub-Atlantean (800 - 27 B.C. )