Allerød Oscillation
Encyclopedia
The Allerød period was a warm and moist global interstadial that occurred at the end of the last glacial period. The Allerød oscillation 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 Allerød 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.
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.
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.
, 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.
, moose
, horse
, Irish elk
and beaver
. The ubiquitous brown bear
was present as well.
hunting
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.
Younger Dryas
The Younger Dryas stadial, also referred to as the Big Freeze, was a geologically brief period of cold climatic conditions and drought between approximately 12.8 and 11.5 ka BP, or 12,800 and 11,500 years before present...
period, which was followed by the present interglacial
Interglacial
An Interglacial period is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age...
period.
In some regions, especially in northern Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
, there is evidence for a cold period known as the Older Dryas
Older Dryas
The Older Dryas was a stadial period between the Bølling and Allerød oscillations during the Pleistocene glacial period of ~11,700—12,000 uncalibrated years ago...
interrupting the interstadial. In such regions the shorter oscillation ending with the Older Dryas is known as the Bølling oscillation
Bølling Oscillation
The Bølling oscillation was a warm interstadial period between the Oldest Dryas and Older Dryas stadials, at the end of the last glacial period. It is named after a peat sequence discovered at Bølling lake, central Jutland...
, and the Allerød period is the interstadial following the Older Dryas.
The Allerød period was named after a type site in Allerød municipality
Allerød municipality
Allerød Kommune is a municipality on the island of Zealand in eastern Denmark. The municipality covers an area of 67 km², and has a total population of 23,493...
in Sjælland, Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
(near Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
), where deposits created during the period were first identified in work published in 1901 by Hartz
Nikolaj Hartz
Nikolaj Eeg Kruse Hartz was a Danish geologist and botanist. He investigated plant and animal remains in deposits from before, during and after the last glaciation...
and Milthers. This Blytt-Sernander
Blytt-Sernander
The Blytt-Sernander classification, or sequence, is a series of north European climatic periods or phases based on the study of Danish peat bogs by Axel Blytt and Rutger Sernander...
period corresponds to Pollen zone
Pollen zone
Pollen zones are a system of subdividing the last glacial period and Holocene paleoclimate using the data from pollen cores. The sequence provides a global chronological structure to a wide variety of scientists, such as geologists, climatologisists, geographists and archaeologists, who study the...
II.
Dating
The start of the Allerød depends on whether an Older DryasOlder Dryas
The Older Dryas was a stadial period between the Bølling and Allerød oscillations during the Pleistocene glacial period of ~11,700—12,000 uncalibrated years ago...
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
Lake Neuchâtel
Lake Neuchâtel is a lake in Romandy, Switzerland . The lake lies mainly in the canton of Neuchâtel, but is also shared by the cantons of Vaud, of Fribourg, and of Bern....
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
, furnish a date of 14,000 BP, calibrated, for the start of the Allerød. Pollen cores from Berezina plain, Belarus
Belarus
Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...
, 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.
The Allerød occurred during the last interstadial of the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
: the Windermere
Windermere
Windermere is the largest natural lake of England. It is also a name used in a number of places, including:-Australia:* Lake Windermere , a reservoir, Australian Capital Territory * Lake Windermere...
of Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, the Woodgrange of Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
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. BirchBirch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
, Aspen
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...
, spruce
Spruce
A spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
, pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
, larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...
and juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
were to be found extensively, mixed with Quercus and Corylus. Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
was to be found in more open regions.
Fauna
Some animals hunted were the red deerRed Deer
The red deer is one of the largest deer species. Depending on taxonomy, the red deer inhabits most of Europe, the Caucasus Mountains region, Asia Minor, parts of western Asia, and central Asia. It also inhabits the Atlas Mountains region between Morocco and Tunisia in northwestern Africa, being...
, moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...
, horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
, Irish elk
Irish Elk
The Irish Elk or Giant Deer , was a species of Megaloceros and one of the largest deer that ever lived. Its range extended across Eurasia, from Ireland to east of Lake Baikal, during the Late Pleistocene. The latest known remains of the species have been carbon dated to about 7,700 years ago...
and beaver
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
. The ubiquitous brown bear
Brown Bear
The brown bear is a large bear distributed across much of northern Eurasia and North America. It can weigh from and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.There are several recognized...
was present as well.
Humans
Humans, who live in houses in north Eurasia were still in the reindeerReindeer
The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one has already gone extinct.Reindeer vary considerably in color and size...
hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...
stage. A variety of Palaeolithic cultures prevailed in Europe: the Federmesser
Federmesser culture
The Federmesser culture is a toolmaking tradition of the late Upper Palaeolithic era, of the Northern European Plain dating to between c. 9800 and 8800 BC...
, Lyngby
Lyngby culture
The Lyngby culture is a proposed name for the combination of the highly similar Ahrensburg and Bromme cultures as one and the same....
, Bromme
Bromme culture
The Bromme culture is a late Upper Paleolithic culture dated to the Allerød Oscillation, ca 9700 BC-9000 BC , a warmer spell between the Elder Dryas and the Younger Dryas, the last cold periods of the late Weichsel Glaciation....
, Ahrensburg
Ahrensburg culture
The Ahrensburg culture was a late Upper Paleolithic culture during the Younger Dryas, the last spell of cold at the end of the Weichsel glaciation. The culture is named after village of Ahrensburg, northeast of Hamburg in the German state of Schleswig-Holstein where wooden arrow shafts and clubs...
and Swiderian
Swiderian culture
Swiderian culture, also published in English literature as Sviderian and Swederian, is the name of Final Palaeolithic cultural complexes in Poland and the surrounding areas. The type-site is Świdry Wielkie, in Otwock. The Swiderian is recognized as a distinctive culture that developed on the sand...
. To the south and far east the Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...
had already begun.