Atlantic

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series Climate level Pollen
zone 		Period
Holocene Subatlantic X 450 BC Until today
IX
Subboreal VIII 3,710-450 BC Chr.
Atlantic VII 7,270-3,710 BC Chr.
VI
Boreal V 8,690-7,270 BC Chr.
Preboreal IV 9,610-8,690 BC Chr.
Pleistocene
Younger dryas period III 10,730-9,700 ± 99 BC Chr.

As the Atlantic or mean warm time , a temporal only vaguely between approx. 8000 BC is given. BC and approx. 4000 BC . Chr in Northern Europe elusive air level denotes that the pollen zones corresponding to VI and VII. This warmest and wettest period of the Blytt-Sernander sequence is also called the “ Holocene Optimum”. The chronology differs depending on the field of science, the status of the work and the geographical scope of application (see also the graphical overview opposite). The symbol key in geology for the period is: qhat. In US English the Atlantic is also known as the "Holocene Thermal Maximum (HTM)".

definition

The term Atlantikum was first introduced into scientific literature in 1876 ​​by Axel Blytt . He distinguished the Atlantic with its Atlantic , i.e. oceanic climate, from the much cooler, preceding Boreal .

Stratigraphy and dating

The Atlantic follows the previous boreal and is in turn replaced by the subsequent subboreal .

The Atlantic can be divided into an older Atlantic , which corresponds to pollen zone VI, and the younger Atlantic (pollen zone VII), with the borderline at 6000 BC. Chr. Lies.

The borders of the Atlantic to the other levels are relatively blurred. It usually begins at 7270 BC. Set. The actual Atlantic is often preceded by a so-called pre - Atlantic or early Atlantic , the lower limit of which is 8040 BC. And its upper limit at 6200 BC. Chr. Lie (calibrated calendar years). According to Rasmussen et al. a. the pre-Atlantic is characterized by a relatively high O 18 isotope content above 33 ppm (the values ​​come from ice cores in Greenland ). For the beginning of the Atlantic there is also the striking cold relapse at 6200 BC. Chr. Kul'kova and others define the Atlantic as the period from 8000 to 5000 BP and divide it into three levels (from young to old) based on seawater levels:

  • Late Atlantic AT3 - 6500 to 5700 years BP - again rising water levels - renewed slight rise in temperature
  • Middle Atlantic AT2 - 7000 to 6500 years BP - relatively low water level - gradual decrease in temperature
  • Early Atlantic AT1 - 8000 to 7000 years BP - high water level - temperature optimum

In the late Atlantic, they also separate two sub-stages:

  • Late Atlantic I - 6500 to 6000 years BP
  • Late Atlantean II - 6000 to 5700 years BP

It is also difficult to find a clear upper limit for the end of the Atlantic. Usually 3710 BC. Some authors also see the after 4800 BC. Chr. Occurring temperature decrease as significant. Biostratigraphy makes use of the Dutch elm decline, which, however, occurred diachronically between 4300 and 3100 BC. Took place.

Chronological order

Mesolithikum Neolithikum Bronzezeit Eisenzeit Yoldia-Meer Ancylussee Littorinameer Flandrische Transgression Dünkirchen-Transgression Präboreal Boreal (Klimastufe) Subboreal Subatlantikum

Note: Only the borders marked with a black dividing line are more or less exact; they are based on annual layers in lake sediments in north-central Europe and, strictly speaking, only apply to the climatic stages. The other boundaries are uncertain and not rigidly set. In particular, the boundary between the Middle and Young Holocene is very variable. Regarding the cultural levels, the regionally different development must be taken into account.

Global Aspects

Reconstruction of the temperature history of the earth over the last 12,000 years

In paleoclimatology , the term refers to a Blytt-Sernander climate stage of the Holocene. Here the discussion about the height and sequence of the Holocene temperature fluctuations continues unabated. As the gray (purely statistical!) Averaging of the graphic shows, sharp boundaries cannot be precisely identified. The Sahara showed a rich animal and plant life at the height of the Atlantic because of the more humid climate and the increased monsoon rain, while it seems to be drier in the current warming period (see also Neolithic subpluvial ).

Temperature development

From a global perspective, it should be noted that the warm phases differed greatly from region to region and were not observed at the same time. There are indications that local temperatures are sometimes significantly higher than those prevailing in the last decades of the 20th century. However, the spatial and temporal resolution of the existing climate proxy does not allow us to draw the conclusion that the Atlantic was warmer than it was in the second half of the 20th century for several decades. According to the IPCC, the term “Holocene temperature optimum” is only of regional relevance and not applicable in a global context.

Sea level

The postglacial sea level rise

The higher temperatures led to a sharp decline in the glaciers . The melting of the North American glaciers in particular led to a rapid rise in sea levels. This in turn probably had about 6,700 BC. The overflow of the Mediterranean into the previously (120 m?) Lower lying Black Sea (see discussion there). In the Alps, the glaciers melted around 7,000 BC. Very strong back, with a striking re-advance from approx. 4,700 BC. The rapid rise in sea level of the Boreal continued in the older Atlantic. At the beginning of the Atlantic, sea level was around 30 meters below today's level. The rate of increase for the older Atlantic was around 15 millimeters / year. About 7000 years ago BP the rise began to weaken drastically and so at the end of the Atlantic the sea level was 2 meters below sea level. The low rate of increase in the Younger Atlantic was only 0.3 millimeters / year.

Baltic region

In the area of ​​today's Baltic Sea , shortly before the beginning of the Atlantic, around 7500 BC. The Ancylus Sea , which emerged from the Yoldia Sea through isostatic land elevation . The level of the Ancylussee was slightly above the sea level of the North Sea at that time . Between 6500 and 6000 BC The land bridge between Denmark and Sweden was broken and the Littorina Sea was formed . This marine incursion caused the sea level to rise quite rapidly by 15 meters in the Baltic Sea region.

North Sea area

Before the beginning of the Atlantic around 9000 BC The Flemish Transgression , which began in BC, caused the sea level in the North Sea to rise rapidly. It reached around 6600 BC. - 45 meters below sea level and around 5100 BC Already - 15 meters below sea level. Thereafter, towards the end of the Atlantic, the sea level fell or came to a standstill in the North Sea region.

Northwest European Aspects

In general, a link between the Holocene heat optimum and palaeobotanical subdivisions, which are generally defined according to Firbas (1949), is problematic. B. Frenzel (1993) even denies that the climate of the Holocene can be read from the vegetation, since humans intervened in it at an early stage and lastingly:

The beginning of the Atlantic, at the beginning of the pollen zone VI after Firbas, is defined in this sense by the re-immigration of oaks and alders into the pine ( birch ) forest that had prevailed up to that point . This happened north of the Alps from the 8th - 7th millennium BC. Since the re-immigration of the different tree species took place from south to north, there are also different chronologies between south and north, as well as favorable and unfavorable locations.

The Atlantic ends after Firbas with the end of its second section, the pollen zone VII, defined by two elm declines in the 4th millennium BC. Since not only this decline today can be attributed mainly to anthropogenic influence (increased snowfall leads to sapwood beetle and fungal infestation, cf. Küster 2003: 83), this classification also has no relation to a defined end of a “climate optimum”.

Temperatures

Map of the glaciations at Lake Agassiz and Lake Ojibway approx. 7900 BP. Teller and Leverington, 2004 (US Geological Survey)
Reconstructed Central Greenland temperature curve.

The climate in Northern Europe was probably not only warmer (up to 2.5 ° C) than at the end of the 20th century, but also more humid. The average temperatures during the Greater Atlantic period before 7600 years BP were similar to the values in the previous 21st century. During the Middle and Later Atlantic, a slow decrease in temperature of around 0.1 ° C per millennium, reaching close to the present, which was only increasingly compensated in the course of the 20th century.

Because of a sharp cold relapse between 6,300 - 6,100 BC, which is now generally recognized at least for the northern hemisphere . BC (in the Alps Misox fluctuation ; English "8.2 ka cold-event") some count the time before to the preceding early warming period ( Boreal ), others consider an "early" Atlantic and correlate this with the Firbas pollen zone VI. In general, newer work z. B. at the LMU Munich, the Geo Research Institute Hanover, as well as the Institute for Silviculture in Göttingen the Atlantikum however - after this incision - about 6,000 BC. Chr.

The Misox fluctuation followed the final breakup of the Laurentian Ice Sheet , which triggered a gigantic pulse of meltwater from the Ojibway and Agassiz lakes in North America. The water masses made their way over Hudson Bay into the North Atlantic . The enormous freshwater input into the North Atlantic largely suppressed the formation of sinking, higher saline water ( density differences ), which normally occurs at high latitudes as a result of the freezing out of sea ​​ice . Due to this disruption of the thermohaline circulation , the heat transport to the North Atlantic via the Gulf Stream came to a standstill. After the fresh water supply had ceased after the ice masses had melted and the inland lake had drained, the deep water formation of the thermohaline circulation started again due to the increased salt content .

Development of vegetation history

During the Atlantic, the deciduous forests of the temperate zone of southern and central Europe expanded to the north, displacing the boreal mixed forest, which, however, continued to exist in mountainous areas. For example, mistletoe , water hazel ( Trapa natans ) and ivy ( Hedera helix ) were present in Denmark . However, the grass pollen was generally in decline. Softwoods such as birch and pine were replaced by hardwoods such as oak , linden ( Tilia cordata and Tilia platyphyllos ), beech , hazel , elm ( Ulmus glabra ), alder and ash, which were advancing from southern regions . This vegetation-historical section is called the Alder-Elm-Linden Period .

In northeastern Europe, the forest in the early Atlantic was only slightly affected by the general rise in temperature. The forest here essentially consisted of pines, the undergrowth consisted of hazel, alder, birch and willow . Only around 7% of the pollen population fell on broad-leaved deciduous trees, during the cooling phase of the Middle Atlantic this then even fell back to the level of the Boreal. With the rise in temperature in the Late Atlantic, the proportion of broad-leaved deciduous trees increased to 34%.

From 5500 to 4500 BC Then along the Danube and the Rhine as well as their northern tributaries, the ceramic band culture penetrated into the forests and partially blocked them with slash and burn. The so-called forest pasture ( Hute ) and leaf hay extraction ( Schneitelwirtschaft ) were operated in a close functional, seasonal context for their livestock farming . Towards the end of the Atlantic, arable land and pasture land had already expanded across large parts of Europe and were now increasingly pushing the original forests back into refuges. There was also the so-called elm fall , a sudden decline in elm pollen , which may be due to the human cultivation of grain and vegetables. In the cooler subboreal area that followed, the forest was then again replaced by open meadow landscapes.

fauna

The best picture of the fauna of the Atlantic can be obtained from kitchen waste from the Ertebølle culture in Denmark. At that time Denmark formed an archipelago whose human inhabitants had mainly settled along the coast. By the sea they had rich fishing grounds and the marshes were frequented by flocks of sea birds. Large numbers of large game such as deer- like and pig-like roamed the forests , but there was also no shortage of small game.

The higher water levels weakened the effects of the toxic zone in the Baltic Sea. As a result, taxa that have become relatively rare, such as Anchovis Engraulis encrasicolus and the three-spined stickleback Gasterosteus aculeatus, were able to spread. There were also pike , whitefish , halibut and ling . In the estuaries, three species of seals and whales were hunted by Mesolithic humans .

As expected, seabirds such as red-throated divers , black-throated divers and gannets were in the majority. Even the Dalmatian pelican ( Pelecanus crispus ), whose northern border now runs in south-eastern Europe, was widespread in Denmark at that time. The capercaillie remained as now on in forest areas.

The canopy area was populated by small mammals such as the ubiquitous squirrel Sciurus vulgaris . The water bat was also very common. The wildcat , pine marten , European polecat ( Mustela putorius ) and wolf hunted in the woods .

On the ground, large mammals roamed as deer , red deer and wild boar among the predators are wolves , lynx and brown bears mention. Former inhabitants of the open grasslands such as the aurochs and the wild horse were, contrary to expectations, also still present. The wild horses were not yet extinct through hunting and not just limited to the steppes of Eastern Europe; they were hunted both by the people of the Ertebølle culture in Denmark and in the Hungarian steppe .

Cultural development

The Atlantic period essentially covers the Late Mesolithic as well as the Early , Middle and Young Neolithic . In northern Europe ( Baltic States , Denmark , England , Northern Germany and Sweden ), the Maglemose culture (9000 to 6500 BC) for the late Mesolithic, as well as the Congemose culture (6000 to 5200 BC) and the Ertebølle culture (5100 to 4100 BC) for the early Neolithic. In the British Isles from 6000 BC. The Neolithic Larnian ( Northern Ireland ) and from 4000 BC. To cite the Obanian (western Scotland ). In today's western North Rhine-Westphalia , the Hülsten group can be found in the late Mesolithic .

At the end of the Mesolithic, the first peasant cultures appeared in Europe, for example from 5800-5500 BC. The La Hoguette group in the southwest and from 5500-4900 BC. The Alföld linear ceramics and the Körös culture in south-eastern Central Europe. In actual Central Europe, linear ceramic tape was the rule at this time . In northern Central Europe and southern Scandinavia, from 4300 B.C. The funnel cup culture .

Onset of the Neolithic

In the Middle East (with Anatolia ) was until 6800/6500 BC. The pre-ceramic Neolithic B can already be found between 6500 and 5500 BC. Was replaced by the Ceramic Neolithic (in the eastern Mediterranean from 6200 BC). In Central Europe, the transition to the Neolithic was from 5500 BC. With the band ceramics , but in the Baltic region much later (from 4300 BC) with the funnel beaker culture.

Megalithic culture

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

The parallel in Europe and the Mediterranean with the Neolithization associated megalithic culture can be in investing in the Normandy and the necropolis of Bougon v to around 4700th Trace back to BC. It ended (not everywhere at the same time) with the outgoing subboreal . The carrier culture of the megalithic systems in Europe was the funnel beaker culture.

literature

  • Heinz Ellenberg : Vegetation of Central Europe with the Alps from an ecological, dynamic and historical perspective (= URB 8104). 5th, heavily changed and improved edition. Ulmer, Stuttgart 1996, ISBN 3-8252-8104-3 .

Individual evidence

  1. ↑ https://www.sciencedirect.com/science/article/abs/pii/S0277379112002168
  2. ^ SO Rasmussen, BM Vinther, HB Clausen, KK Andersen: Greenland Ice Core Chronology 2005 (GICC05) Early Holocene section . In: IGBP PAGES / World Data Center for Paleoclimatology Data Contribution Series # 2006-119. NOAA / NCDC Paleoclimatology Program . Boulder CO, USA 2006.
  3. ↑ MA Kul'kova, AN Mazurkevich, PM Dolukhanov: Chronology and Palaeoclimate of Prehistoric Sites in Western Dvina-Lovat 'Area of ​​North-western Russia . In: Geochronometria, 20 . 2001, p. 87-94 .
  4. ↑ St. Kröpelin, R. Kuper: Holocene Climate Change and Settlement History of the Eastern Sahara. In: Geographical Rundschau. 59-4, 2007, pp. 22-29.
  5. ↑ IPCC, Climate Change 2007: Working Group I: The Physical Science Basis: 6.5.1.3 Was Any Part of the Current Interglacial Period Warmer than the Late 20th Century? on-line
  6. ^ Kurt Nicolussi: Environmental and climate development after the ice age. In: Archeology in Germany. Issue 4, 2008, p. 22ff.
  7. ↑ Jörg FW Negendank: The holocene: consideration with regard to its climate and climate archives. In: H. Fischer, Th. Kumke, G. Lohmann, G. Flöser, H. Miller, H. von Storch, JFW Negendank (Eds.): The climate in historical times. Towards a Synthesis of Holocene Proxy Data and Climate Models. Springer, Berlin 2004.
  8. ^ Franz Firbas: Late and post-glacial forest history of Central Europe north of the Alps. Two volumes. Fischer, Jena 1949, 1952.
  9. ↑ B. Frenzel: Ecological consequences of the development from forest to forest in Central Europe. In: Problems of environmental research from a historical perspective. Bavarian Akad. D. Sciences, Munich 1993, pp. 141–159.
  10. ^ AJ Kalis, J. Merkt, J. Wunderlich: Environmental changes during the Holocene climatic optimum in central Europe - human impact and natural causes. In: Quaternary Science Reviews 22, 2003, pp. 33-79.
  11. ↑ Hansjörg Küster : History of the forest - from prehistoric times to the present . Beck, Munich 2003.
  12. ↑ cf. RB Alley: The Younger Dryas cold interval as viewed from central Greenland . In: Quaternary Science Reviews . January 2000, doi : 10.1016 / S0277-3791 (99) 00062-1 .
  13. ↑ Heikki Seppä, Karin Antonsson, Maija Heikkilä, Anneli Poska: Paper No. 45-1 Holocene Annual Mean Temperature Changes in the Boreal Zone of Europe: Pollen-based Reconstructions (abstract). XVI INQUA Congress, 2003, accessed November 11, 2010 .
  14. ↑ Peter Marcott, Jeremy D. Shakun, Peter U. Clark, Alan C. Mix: A Reconstruction of Regional and Global Temperature for the Past 11,300 Years . (PDF) In: Science . 6124, No. 269, March 2013, pp. 1198-1201. doi : 10.1126 / science.1228026 .
  15. ↑ RB Alley: GISP2 Ice Core Temperature and Accumulation Data. IGBP PAGES / World Data Center for Paleoclimatology Data Contribution Series # 2004-013. NOAA / NGDC Paleoclimatology Program, Boulder CO, USA, 2004.
  16. ↑ Peter Rasmussen, Mikkel Ulfeldt Hede, Nanna Noe-Nygaard, Annemarie L. Clarke, Rolf D. Vinebrooke: Environmental response to the cold climate event 8200 years ago as recorded at Højby Sø, Denmark. Geological Survey of Denmark and Greenland Bulletin, 15, 2008, pp. 57–60 ( PDF )
  17. ↑ Barber, DC et al .: Forcing of the cold event 8,200 years ago by catastrophic drainage of Laurentide Lakes . In: Nature . tape 400 (6742) , 1999, pp. 344-8 .
  18. ↑ a b Peterken (1993)
  19. ^ Róbert Kertész: Mesolithic Hunter-Gatherers in the Northwestern Part of the Great Hungarian Plain . In: Praehistoria . tape 3 , 2002.