Bølling Oscillation

The Bølling Oscillation was a warm period that occurred during the final stages of the last glaciation of Europe. It corresponds to Pollen zone 1b. Named after a peat sequence discovered at Bølling lake, central Jutland, it was subsequent to the Oldest Dryas and preceded the Older Dryas periods. However, if the Older Dryas is not present or is not detected in the evidence of a region, the Bølling-Allerød is considered one interstadial and period.

Dates

The beginning of the Bølling is also the high-resolution date for the sharp temperature rise marking the end of the Oldest Dryas at 14,670 BP. Roberts (1998) uses 15,000. A range of 14,650-14,000 BP calibrated has been assigned to the Bølling layer of the excavation at Lake Neuchatel, Switzerland, 1992-1993. The Oxygen isotope record from Greenland ice includes the Bølling warm peak between 14,600 and 14,100 BP. Most of the recent dates available fall within a few hundred years of these.

Flora

Of the two periods, Bølling and Allerød, Bølling is the warmer and came on more suddenly. During it sea level rose more than 100 m due to glacial melt. Ice uncovered large parts of north Europe and temperate forests covered Europe from 29 deg. to 41 deg. north latitude. After some pioneer vegetation, such as "Salix polaris" and "Dryas octopetala", hardwoods, such as "Quercus", and softwoods, "Betula" and "Pinus", spread northward for a brief few hundred years.

Fauna

During this time late Pleistocene animals spread northward from refugia in the three peninsulas, Spain, Italy and the Balkans. Geneticists can identify the general location by studying degrees of consanguinity in the modern animals of Europe. The hunting camps of ancient man remain a major source of faunal fossils.

Animals hunted by man are predominantly the big-game mammals: reindeer, horse, saiga, antelope, bison, woolly mammoth and wooly rhinoceros. In the alpine regions ibex and chamois were hunted. Throughout the forest were red deer. Smaller animals, such as fox, wolf, hare and squirrel also appear. Salmon was fished. For more details, see also the references to fauna under Oldest Dryas and Older Dryas.

Human cultures

Humans reentered the forests of Europe in search of big game, which they were beginning to hunt relentlessly, many to extinction. Their cultures were the last of the Late Upper Palaeolithic. Magdalenian hunters moved up the Loire into the Paris Basin. In the drainage basin of the Dordogne, the Perigordian prevailed. The Epigravettian dominated Italy. In the north, the Hamburgian and Federmesser cultures are found. In the middle east, the pre-agricultural Natufian settled around the east coast of the Mediterranean to exploit wild cereals, such as emmer and two-row barley. In the Allerød they would begin to domesticate these plants.

ee also

* Antarctic Cold Reversal
* Ice age
* Last Glacial Maximum
* Younger Dryas

External links

* [http://www.cio.phys.rug.nl/HTML-docs/Verslag/97/AR-01.htm Chronology of the Netherlands]
* [http://www.lehigh.edu/~ziy2/pubs/YuGpQPreprint.pdf The Bølling-Allerød]
* [http://www.pnas.org/cgi/content/full/97/4/1359 Sensitivity and rapidity of vegetational response to abrupt climate change]
* [http://www.vancouver.wsu.edu/fac/harders/Spring2003/chapter15.pdf Short-term Climate Variability]
* [http://www.doggerland.dk/PUBLIKATIONER/artikelsettlemen.html Settlements of the Hamburgian and Federmesser Cultures]