World Library  
Flag as Inappropriate
Email this Article

Allerød oscillation

Article Id: WHEBN0000952880
Reproduction Date:

Title: Allerød oscillation  
Author: World Heritage Encyclopedia
Language: English
Subject: Older Dryas, Pleistocene, Younger Dryas, Oldest Dryas, Late Pleistocene
Collection: Blytt–sernander System, Climate History, Nordic Stone Age, Pleistocene
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Allerød oscillation

The Allerød oscillation (Danish: Allerødtiden) was a warm and moist global interstadial that occurred at the end of the last glacial period. It raised temperatures in the northern Atlantic region to almost present-day levels, before they declined again in the succeeding Younger Dryas period, which was followed by the present interglacial period.

In some regions, especially in northern Eurasia, there is evidence for a cold period known as the Older Dryas interrupting the interstadial. In such regions the shorter oscillation ending with the Older Dryas is known as the Bølling oscillation, and the Allerød period is the interstadial following the Older Dryas.

The Allerød period was named after a type site in Furesø municipality in Sjælland, Denmark (near Copenhagen), where deposits created during the period were first identified in work published in 1901 by Hartz and Milthers. This Blytt-Sernander period corresponds to Pollen zone II.

Contents

  • Dating 1
  • Flora 2
  • Fauna 3
  • Humans 4
  • Sources 5
  • External links 6

Dating

The start of the Allerød depends on whether an Older Dryas is present and how much time is to be allotted to the latter. A conventional date of 14,000 BP is typical. Roberts (1998) uses 13,000 BP for the end of the period.

The Greenland oxygen isotope record shows the warming identified with the Allerød to be after about 14,100 BP and before about 12,900 BP. C-14 dates from an excavation on the shore of Lake Neuchatel, Switzerland, furnish a date of 14,000 BP, calibrated, for the start of the Allerød. Pollen cores from Berezina plain, Belarus, give 11,800–10,900 BP uncal. Various researchers have similar ranges: 12,000–11,000, 11,700–11,000, etc. They all seem to roughly concur. The interstadial ended abruptly with a cold period that reduced temperatures back to near-glacial levels within a decade.[1]

The Allerød occurred during the last interstadial of the Pleistocene: the Windermere of Britain, the Woodgrange of Ireland and the Two Creeks Interval of North America. Although interstadials are defined by region, the Allerød period is not, being global in its effects; that is, the temperature and sea level rose everywhere, not just in north Europe.

Flora

During the Allerød, which foreshadowed the modern climate, mixed evergreen and deciduous forests prevailed in Eurasia, more deciduous toward the south, just as today. Birch, Aspen, spruce, pine, larch and juniper were to be found extensively, mixed with Quercus and Corylus. Poaceae was to be found in more open regions.

Fauna

Some animals hunted were the red deer, moose, horse, Irish elk and beaver. The ubiquitous brown bear was present as well.

Humans

Humans in north Eurasia were still in the hunting-gathering stage. A variety of Palaeolithic cultures prevailed in Europe: the Federmesser, Lyngby, Bromme, Ahrensburg and Swiderian. To the south and far east the Neolithic had already begun.

Sources

  1. ^ Wade, Nicholas, "Before the Dawn", Penguin Press, 2006. pp. 123

External links

  • Belarus
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.