Oldest Dryas
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The Oldest Dryas is a
biostratigraphic Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bio ...
subdivision layer corresponding to a relatively abrupt climatic cooling event, or
stadial Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate while interstadials are periods of warmer climate. Each Quaternary climate phase is associated with a Ma ...
, which occurred during the last glacial retreat. The time period to which the layer corresponds is poorly defined and varies between regions, but it is generally dated as starting at 18.5–17 thousand years ( ka) before present (BP) and ending 15–14 ka BP. As with the Younger and
Older Older is the comparative form of "old". It may also refer to: Music: * ''Older'' (album), the third studio album from George Michael (released in 1996) ** "Older" (George Michael song) * "Older", a song on the 1999 album '' Long Tall Weekend'' ...
''Dryas'' events, the stratigraphic layer is marked by abundance of the pollen and other remains of ''
Dryas octopetala ''Dryas octopetala'', the mountain avens, eightpetal mountain-avens, white dryas or white dryad, is an Arctic–alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies. The specific epithe ...
'', an indicator species that colonizes arctic-alpine regions. In the
Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Swi ...
, the Oldest Dryas corresponds to the
Gschnitz Gschnitz () is a municipality with 415 inhabitants (1 January 2011) in the south of North Tyrol. Setting Gschnitz is at the end of the valley of the same name that branches off from the Wipptal at Steinach am Brenner. The municipality borders are ...
stadial of the
Würm glaciation The Würm glaciation or Würm stage (german: Würm-Kaltzeit or ''Würm-Glazial'', colloquially often also ''Würmeiszeit'' or ''Würmzeit''; cf. ice age), usually referred to in the literature as the Würm (often spelled "Wurm"), was the last g ...
. The term was originally defined specifically for terrestrial records in the region of
Scandinavia Scandinavia; Sámi languages: /. ( ) is a subregion in Northern Europe, with strong historical, cultural, and linguistic ties between its constituent peoples. In English usage, ''Scandinavia'' most commonly refers to Denmark, Norway, and Swe ...
, but has come to be used both for ice core stratigraphy in areas across the world, and to refer to the time period itself and its associated temporary reversal of the glacial retreat.


Flora

During the Oldest Dryas, Europe was treeless and similar to the Arctic
tundra In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mou ...
, but much drier and grassier than the modern tundra. It contained shrubs and herbaceous plants such as the following: :* Poaceae, grasses :*''
Artemisia Artemisia may refer to: People * Artemisia I of Caria (fl. 480 BC), queen of Halicarnassus under the First Persian Empire, naval commander during the second Persian invasion of Greece * Artemisia II of Caria (died 350 BC), queen of Caria under th ...
'' :*''
Betula nana ''Betula nana'', the dwarf birch, is a species of birch in the family Betulaceae, found mainly in the tundra of the Arctic region. Description It is a monoecious, deciduous shrub growing up to high. The bark is non-peeling and shiny red-copp ...
'', dwarf birch :*'' Salix retusa'', dwarf willow :*''
Dryas octopetala ''Dryas octopetala'', the mountain avens, eightpetal mountain-avens, white dryas or white dryad, is an Arctic–alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies. The specific epithe ...
'' Image:Grasslands-menggu.jpg, Grassland (
Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of the People's Republic of China. Its border includes most of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a ...
) Image:Artemisia_vulgaris_-_Köhler–s_Medizinal-Pflanzen-016.jpg, ''Artemisia vulgaris'' Image:Betula nana0.jpg, ''Betula nana'' Image:Mountainavens2.jpg, ''Dryas octopetala''


Fauna

Species were mainly Arctic but during the Glacial Maximum, the warmer weather species had withdrawn into refugia and began to repopulate Europe in the Oldest Dryas. The brown bear, ''
Ursus arctos The brown bear (''Ursus arctos'') is a large bear species found across Eurasia and North America. In North America, the populations of brown bears are called grizzly bears, while the subspecies that inhabits the Kodiak Islands of Alaska is kno ...
'', was among the first to arrive in the north. Genetic studies indicate North European brown bears came from a refugium in the
Carpathians The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains at . The range stretches ...
of
Moldavia Moldavia ( ro, Moldova, or , literally "The Country of Moldavia"; in Romanian Cyrillic alphabet, Romanian Cyrillic: or ; chu, Землѧ Молдавскаѧ; el, Ἡγεμονία τῆς Μολδαβίας) is a historical region and for ...
. Other refugia were in
Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
,
Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...
and
Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders ...
. The bears would not have returned north except in pursuit of food. The tundra must already have been well populated. It is likely that the species hunted by humans at
Lake Neuchâtel Lake Neuchâtel (french: Lac de Neuchâtel ; frp, Lèc de Nôchâtél; german: Neuenburgersee) is a lake primarily in Romandy, in the French-speaking part of Switzerland. The lake lies mainly in the canton of Neuchâtel, but is also shared by t ...
in Switzerland by the end of the period were present during it. Here are other animals present: Aves :*'' Gavia arctica'', black-throated diver :*''
Podiceps nigricollis The black-necked grebe or eared grebe (''Podiceps nigricollis'') is a member of the grebe family of water birds. It was described in 1831 by Christian Ludwig Brehm. There are currently three accepted subspecies, including the nominate subspeci ...
'', black-necked grebe :*''
Cygnus cygnus The whooper swan ( /ˈhuːpə(ɹ) swɒn/) (''Cygnus cygnus''), also known as the common swan, pronounced ''hooper swan'', is a large northern hemisphere swan. It is the Eurasian counterpart of the North American trumpeter swan, and the type speci ...
'', whooper swan :*''
Aquila chrysaetos The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of ...
'', golden eagle Image:Gavia arctica1.jpg, ''Gavia arctica'' Image:Podiceps nigricollis naumann.jpg, ''Podiceps nigricollis'' Image:Cygnus cygnus from zh.JPG, ''Cygnus cygnus'' Image:Aquila chrysaetos large drawing.jpg, ''Aquila chrysaetos'' The above birds are primarily maritime. They must have fed in the copious glacial waters of the north that were just beginning to be released.
Fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...
:*''
Lota lota The burbot (''Lota lota'') is the only gadiform (cod-like) freshwater fish. It is also known as bubbot, mariah, loche, cusk, freshwater cod, freshwater ling, freshwater cusk, the lawyer, coney-fish, lingcod, and eelpout. The species is closely ...
'', burbot :*''
Thymallus thymallus ''Thymallus thymallus'', the grayling or European grayling, is a species of freshwater fish in the salmon family Salmonidae. It is the only species of the genus ''Thymallus'' (the graylings) native to Europe, where it is widespread from the Unit ...
'', grayling :*'' Rutilus rutilus'', roach :*''
Salmo trutta The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morph ...
'', trout :*''
Salvelinus ''Salvelinus'' is a genus of salmonid fish often called char or charr; some species are called "trout". ''Salvelinus'' is a member of the subfamily Salmoninae within the family Salmonidae. The genus has a northern circumpolar distribution, and ...
alpinus'', char Image:Tarfala.jpg, Glacial stream Image:Trüsche Walchensee.jpg, ''Lota lota'' Image:Bachforelle Zeichnung.jpg, ''Salmo trutta'' Image:Röding, Iduns kokbok.jpg, ''Salvelinus'' The smaller mammals of the food chain inhabited the herbaceous blanket of the tundra:
Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, and h ...
:*'' Discrotonyx torquatus'', collared lemming :*''
Microtus oeconomus The tundra vole (''Microtus oeconomus'') or root vole is a medium-sized vole found in Northern and Central Europe, Asia, and northwestern North America, including Alaska and northwestern Canada. In the western part of the Netherlands, the tundr ...
'', root vole :*''
Microtus arvalis The common vole (''Microtus arvalis'') is a European rodent. Distribution and habitat The common vole is hardly restricted in means of distribution and habitat and inhabits large areas of Eurasia but, apart from the Orkney vole, not the Bri ...
'', common vole :*'' Chionmys nivalis'', snowy vole
Leporidae Leporidae is the family of rabbits and hares, containing over 60 species of extant mammals in all. The Latin word ''Leporidae'' means "those that resemble ''lepus''" (hare). Together with the pikas, the Leporidae constitute the mammalian order ...
:*'' Lepus timidus'', Arctic hare
Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...
:*'' Marmota marmota'', marmot Image:TundraVole23.jpg, ''Microtus oeconomus'' Image:Feldmaus Microtus arvalis.jpg, ''Microtus arvalis'' Image:Arctic Hare.jpg, ''Lepus timidus'' Image:Marmota marmota Alpes1.jpg, ''Marmota marmota'' In addition to bears and birds were other predators of the following small animals: Carnivora :*'' Felis lynx'', lynx :*''
Alopex lagopus The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Tundra#Arctic tundra, Arctic tundra biome. It is well a ...
'', Arctic fox :*''
Canis lupus The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...
'', wolf Image:Lynx lynx poing.jpg, Lynx (or Felis) lynx Image:Alopex lagopus standing on Nizke Island.jpg, ''Alopex lagopus'' Image:Canis lupus portrait.jpg, ''Canis lupus'' Image:IcelandicHorseInWinter.jpg, Icelandic horse, perhaps like ''Equus ferus'' Humans were interested in the large mammals, which included: :*'' Rangifer tarandus'', reindeer :*''
Equus ferus The wild horse (''Equus ferus'') is a species of the genus ''Equus'', which includes as subspecies the modern domesticated horse (''Equus ferus caballus'') as well as the endangered Przewalski's horse (''Equus ferus przewalskii''). The Europea ...
'', wild horse :*'' Capra ibex'', ibex At some point, the larger mammals arrived: hyena,
woolly rhinoceros The woolly rhinoceros (''Coelodonta antiquitatis'') is an extinct species of rhinoceros that was common throughout Europe and Asia during the Pleistocene epoch and survived until the end of the last glacial period. The woolly rhinoceros was a me ...
,
cave bear The cave bear (''Ursus spelaeus'') is a prehistoric species of bear that lived in Europe and Asia during the Pleistocene and became extinct about 24,000 years ago during the Last Glacial Maximum. Both the word "cave" and the scientific name ' ...
and
mammoth A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
. Image:Albino raindeer.jpg, Rangifer tarandus Image:CapraIbex-1.jpg, Capra ibex Image:Wooly rhinoceros.jpg, Woolly rhinoceros Image:Mammouth.png, Mammoth


See also

*
Older Dryas The Older Dryas was a stadial (cold) period between the Bølling and Allerød interstadials (warmer phases), about 14,000 years Before Present, towards the end of the Pleistocene. Its date is not well defined, with estimates varying by 400 years ...
*
Younger Dryas The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stag ...


Notes


References


Further reading

* Ehlers, Gibbard, Hughes (eds) (2011
''Quaternary Glaciations - Extent and Chronology: A Closer Look''
Elsevier * Bradley, Raymond S. (2013
''Paleoclimatology: Reconstructing Climates of the Quaternary''
Academic Press


External links


the HoloceneBrown Bears
{{Ice Ages Chronology Holocene Ice ages Last Glacial Period Climate history Pleistocene Paleoclimatology Palynology Blytt–Sernander system Historical eras