Quaternary

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

In the Historical Geology Quaternary represents a chronostratigraphisches system or a geochronological period. It begins at about 2.6 million years ago and continues to this day. It covers the entire Quaternary Ice Age, in which took place the humanization of man today.

After Antarctica was glaciated already a long time, it came at the beginning of Gelasiums also for glaciations in the Northern Hemisphere. The beginning of this glaciation period, which continues with a change from cold periods and warm periods even today, is considered by geologists as a suitable definition of the Quaternary period of the previous period of the Neogene. Previously a long time had been drawn the line between " tertiary " and the Quaternary 1.806 million years. Because of the geologically speaking relatively short period of the Quaternary and its different stages of development in marine and continental area was a consistent definition for the preceding period are difficult or impossible possible, the border of the Tertiary was controversial. This led in 2004 to an even deletion of the terms Tertiary and Quaternary of the Geological time scale.

In 2005, the efforts of the various associations for Quaternary were successful, at least the term Quaternary again granted a place in the stratigraphy. However, requiring yet more years of discussion until the reintroduction of the Quaternary was decided in the geological time scale. The Quaternary is now following within the Cenozoic ( Cenozoic ) the periods of the Paleogene and the Neogene. In this sense, it is defined by the chronostratigraphic stage of Gelasiums as its lowermost unit starts and 2.588 million years before present. For a better distinction from the distant past periods has been reached and the entire period of the climate shifts of the earth could be summarized under the term Quaternary.

At the same time the Pleistocene epoch of the Quaternary older, was also extended by the Gelasian, and thereby the Pliocene, the youngest epoch of the Neogene to shorten the same time period. On the Pleistocene follows the Quaternary within the Holocene, a climatically warm period within the ice age, which includes the last past 11,700 years to the present.

Emergence of the concept

The term " Quaternary " was already used in 1760 by Giovanni Arduino in the literature, when he distinguished four successive groups of layers: Primary, Secondary, Tertiary and Quaternary. Jules Desnoyers in 1829 reached the term again in order to address sediments in the Paris Basin, which were significantly younger than the Tertiary deposits. The quaternary layers were indeed in certain basins very powerful, but of little geological age. This led to a very unbalanced subdivision of the Cenozoic ( Cenozoic ) in the 63.7 million years lasting Tertiary and the Quaternary lasting only 1.6 million years. This imbalance led to the redefinition of the Geological Time Scale (GTS 2004) to replace the terms Tertiary and Quaternary and Neogene Paleogene by the terms with new stratigraphic boundaries and meanings. These limits, however, were revised in the International Stratigraphic Chart of the ICS in 2008, without encroaching on a final decision. The final ratification on June 30, 2009.

Subdivision

The Quaternary is divided as follows:

• System: Quaternary ( 2.588 to 0 mya ) Series: Holocene ( 0.0117 to 0 mya ) Level: Holocene ( 0.0117 to 0 mya )

• Level: Upper Pleistocene ( Tarantium ) ( 0.126 to 0.0117 mya )
• Level: Middle Pleistocene ( Ionium ) ( 0.781 to 0.126 mya )
• Level: Early Pleistocene ( Calabrium ) ( 1.806 to 0.781 mya )
• Level: Gelasian ( 2.588 to 1.806 mya )