|Time span formality||Formal|
|Lower boundary definition||
|Lower boundary GSSP||Monte San Nicola Section, |
(1 times pre-industrial)
|Mean surface temperature||c. 14 °C|
(0 °C above modern)
The Quaternary (
The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused.
The Quaternary Period follows the Neogene Period and extends to the present. The Quaternary covers the time span of glaciations classified as the Pleistocene, and includes the present interglacial time-period, the Holocene.
This places the start of the Quaternary at the onset of Northern Hemisphere glaciation approximately 2.6 million years ago (mya). Prior to 2009, the Pleistocene was defined to be from 1.805 million years ago to the present, so the current definition of the Pleistocene includes a portion of what was, prior to 2009, defined as the Pliocene.
Quaternary stratigraphers usually worked with regional subdivisions. From the 1970s, the
This led to the problem that the proposed base of the Pleistocene was at 1.805 million years ago, long after the start of the major glaciations of the northern hemisphere. The ICS then proposed to abolish use of the name Quaternary altogether, which appeared unacceptable to the International Union for Quaternary Research (INQUA).
In 2009, it was decided to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.588 mya and including the Gelasian Stage, which was formerly considered part of the Neogene Period and Pliocene Epoch. This was later revised to 2.58 mya.
The Anthropocene has been proposed as a third epoch as a mark of the anthropogenic impact on the global environment starting with the Industrial Revolution, or about 200 years ago. The Anthropocene is not officially designated by the ICS, but a working group has been working on a proposal for the creation of an epoch or sub-period.
The 2.58 million years of the Quaternary represents the time during which recognisable humans existed. Over this geologically short time period there has been relatively little change in the distribution of the continents due to plate tectonics.
The Quaternary geological record is preserved in greater detail than that for earlier periods.
The major geographical changes during this time period included the emergence of the Strait of
The current extent of Hudson Bay, the Great Lakes and other major lakes of North America are a consequence of the Canadian Shield's readjustment since the last ice age; different shorelines have existed over the course of Quaternary time.
In 1821, a Swiss engineer, Ignaz Venetz, presented an article in which he suggested the presence of traces of the passage of a glacier at a considerable distance from the Alps. This idea was initially disputed by another Swiss scientist, Louis Agassiz, but when he undertook to disprove it, he ended up affirming his colleague's hypothesis. A year later, Agassiz raised the hypothesis of a great glacial period that would have had long-reaching general effects. This idea gained him international fame and led to the establishment of the Glacial Theory.
In time, thanks to the refinement of geology, it has been demonstrated that there were several periods of glacial advance and retreat and that past temperatures on Earth were very different from today. In particular, the
During this time, substantial glaciers advanced and retreated over much of North America and Europe, parts of South America and Asia, and all of Antarctica.
Flora and Fauna
This section needs expansion. You can help by adding to it. (March 2023)
There was a major
- ^ Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J.-X. (January 2020). "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. Retrieved 23 February 2020.
- . Retrieved 11 November 2019.
- . Retrieved 8 December 2020.
- ^ Cohen, K.M.; Finney, S.C.; Gibbard, P.L.; Fan, J.-X. "International Chronostratigraphic Chart 2013" (PDF). stratigraphy.org. ICS. Retrieved 15 June 2014.
- ^ a b c "Stratigraphic Chart 2022" (PDF). International Stratigraphic Commission. February 2022. Retrieved 4 June 2022.
- S2CID 27485445.
- ISBN 978-0582101661.
- ^ See:
- Arduino, Giovanni (1760). "Lettera Segonda di Giovanni Arduino … sopra varie sue osservazioni fatte in diverse parti del territorio di Vicenza, ed altrove, apparenenti alla Teoria terrestre, ed alla Mineralogia" [Second letter of Giovani Arduino … on his various observations made in different parts of the territory of Vincenza, and elsewhere, concerning the theory of the earth and mineralogy]. Nuova Raccolta d'Opuscoli Scientifici e Filologici [New collection of scientific and philogical pamphlets] (in Italian). 6: 133 (cxxxiii)–180(clxxx). Available at: Museo Galileo (Florence (Firenze), Italy) From p. 158 (clviii): "Per quanto ho potuto sinora osservavare, la serie di questi strati, che compongono la corteccia visibile della terra, mi pare distinta in quattro ordini generali, e successivi, senza considerarvi il mare." (As far as I have been able to observe, the series of these layers that compose the visible crust of the earth seems to me distinct in four general orders, and successive, not considering the sea.)
- English translation: Ell, Theodore (2012). "Two letters of Signor Giovanni Arduino, concerning his natural observations: first full English translation. Part 2". Earth Sciences History. 31 (2): 168–192.
- ^ Desnoyers, J. (1829). "Observations sur un ensemble de dépôts marins plus récents que les terrains tertiaires du bassin de la Seine, et constituant une formation géologique distincte; précédées d'un aperçu de la nonsimultanéité des bassins tertiares" [Observations on a set of marine deposits [that are] more recent than the tertiary terrains of the Seine basin and [that] constitute a distinct geological formation; preceded by an outline of the non-simultaneity of tertiary basins]. Annales des Sciences Naturelles (in French). 16: 171–214, 402–491. From p. 193: "Ce que je désirerais … dont il faut également les distinguer." (What I would desire to prove above all is that the series of tertiary deposits continued – and even began in the more recent basins – for a long time, perhaps after that of the Seine had been completely filled, and that these later formations – Quaternary (1), so to say – should not retain the name of alluvial deposits any more than the true and ancient tertiary deposits, from which they must also be distinguished.) However, on the very same page, Desnoyers abandoned the use of the term "quaternary" because the distinction between quaternary and tertiary deposits wasn't clear. From p. 193: "La crainte de voir mal comprise … que ceux du bassin de la Seine." (The fear of seeing my opinion in this regard be misunderstood or exaggerated, has made me abandon the word "quaternary", which at first I had wanted to apply to all deposits more recent than those of the Seine basin.)
- ^ "Late Quaternary Fluvial and Coastal Sequences Chapter 1: Introduction" (PDF). Retrieved 26 March 2017.
- ^ Wiz Science™ (28 September 2015), Quaternary - Video Learning, archived from the original on 7 April 2017, retrieved 26 March 2017
- ^ "See the 2009 version of the ICS geologic time scale".
- ^ "International Chronostratigraphic Chart ChangeLog for 2012-2022". International Chronostratigraphic Chart. International Commission on Stratigraphy. February 2022. Retrieved 4 June 2022.
- S2CID 2624037.
- ^ "Working Group on the 'Anthropocene'". Subcomission on Quaternary Stratigraphy. Retrieved 16 June 2014.
- ^ Ghosh, Pallab (4 March 2015). "'First human' discovered in Ethiopia". BBC News. London. Retrieved 19 April 2015.
- S2CID 129316719.
- ^ Balbas, A.M., Barth, A.M., Clark, P.U., Clark, J., Caffee, M., O'Connor, J., Baker, V.R., Konrad, K. and Bjornstad, B., 2017. 10Be dating of late Pleistocene megafloods and Cordilleran Ice Sheet retreat in the northwestern United States. Geology, 45(7), pp. 583-586.
- ISBN 9780444515926.
- ^ Haynes. "Stanford Camelops" (PDF). Archived from the original (PDF) on 9 March 2014.
- ^ "Extinct American Cheetah Fact Sheet". library.sandiegozoo.org. Archived from the original on 4 March 2016. Retrieved 10 December 2015.
- Subcommission on Quaternary Stratigraphy
- Stratigraphical charts for the Quaternary
- Version history of the global Quaternary chronostratigraphical charts (from 2004b)
- Silva, P.G. C. Zazo, T. Bardají, J. Baena, J. Lario, A. Rosas, J. Van der Made. 2009, "Tabla Cronoestratigrafíca del Cuaternario en la Península Ibérica - V.2". [Versión PDF, 3.6 Universidad de Salamanca, Spain. (Correlation chart of European Quaternary and cultural stages and fossils)
- Welcome to the XVIII INQUA-Congress, Bern, 2011 Archived 21 March 2012 at the Wayback Machine
- Quaternary (chronostratigraphy scale)
- Media related to Quaternaryat Wikimedia Commons