Oldest dryas period

Series / ( Glacial )	Climatic levels	Period v. Chr.
Holocene
	Preboreal	9,610-8,690
Pleistocene ( Vistula - Late Glacial )
	Younger dryas period	10,730-9,700 ± 99
	Alleröd Interstadial	11,400-10,730
	Older dryas period	11,590-11,400
	Bölling-Interstadial	11,720-11,590
	Oldest dryas period	11,850-11,720
	Meiendorf-Interstadial	12,500-11,850
( Vistula - high glacial )
	Mecklenburg phase

The oldest Dryas time , also oldest tundra time or Dryas 1 is in the history of the earth the name for a stratigraphic unit between the Meiendorf-Interstadial and the Bölling-Interstadial of the Weichsel-Late Glacial ( Quaternary ). The oldest dryas period began 13,800 years ago Before Present (BP) and ended at 13,670 varven years BP (according to the varven chronology in the Meerfelder Maar ), i.e. 11,850 to 11,720 BC. The period was marked by a renewed, clear cooling. The summers were probably only slightly cooler than in the previous Meiendorf-Interstadial, but the winters were probably colder or snowier.

Naming and conceptual history

The name was coined by Johannes Iversen in 1942 for a cooler phase of the Vistula Late Glacial between the first slightly warmer Meiendorf Interstadial and the significantly warmer Alleröd Interstadial . It is derived from the botanical genus name Dryas , the scientific name for the silver spice . In later publications he also referred to this phase as Daniglacial tundra period or earliest tundra period .

definition

The oldest Dryas period was defined by Johannes Iversen in the type profile Bølling Sø without a lower limit. Burchard Menke later referred to this maximum of non-tree pollen as older tundra time .

Stratigraphy and Correlation

The oldest Dryas period, also known as the Aegelsee fluctuation in southern Germany , follows the Meiendorf interstadial in northern Germany ; it is followed by the Bölling-Interstadial . In North America and in the North Atlantic region , the Oldest Dryas but is considered Older Dryas or as IBCP ( Engl. Inter Bölling Cold phase (abbreviated around the room) Norway BCP II - Bölling Cold Phase II ).

The oldest dryas period is equivalent to the Greenland Interstadial 1d ( GI-1d ). According to Hoek (1997) it corresponds to pollen zone 1c .

Dating

Deposits from the oldest Dryas period are particularly widespread in northern Germany. The Geozentrum Hannover dates this climatic phase to 13,860 to 13,730 cal BP (calibrated calendar years) or 11910 to 11780 BC. BC , which is a deviation from the varven chronology in the Meerfelder Maar. Lowe et al. (2008) give with 12075 to 11954 BC A somewhat older period of time, van Raden a. a. (2012) recently advocate the period from 12094 to 11958 BC. Chr.

Volcanism

Smaller eruptions occurred around 13,700 ± 1,600 years BP at the Puy Tartaret in the south of the Chaîne des Puys in the French massif Central and there were also eruptions at the Puy de Côme .

Environmental parameters

During the oldest dryas, there was a strong rise in sea level caused by the meltwater pulse 1A .

Oxygen isotopes

Compared to the warm phases that limit it (Meiendorf-Interstadial and Bölling-Interstadial), the oldest Dryas period has δ ¹⁸ O values that are 2 ‰ lower , with a minimum of -40 ‰ SMOW (VPDB).

Temperatures

On the basis of Coleoptera , Atkinson et al. (1987) found a temperature decrease in the summer average temperatures of 2.5 ° C (from 16.5 to 14 ° C) in Great Britain compared to the values ​​in the Meiendorf interstadial. Similarly, Van Geel et al. (1989) had also determined for the Netherlands a decrease in summer temperatures of up to 4 ° C during the oldest dryas period.

Vegetation development

The oldest dryas period is characterized by a non-tree pollen maximum after the Hippophaë maximum ( sea buckthorn ) at the end of the Meiendorf interstadial. The plant community suggests a steppentundra .

The cold snap led to a clearing of the birch forests that had grown up in the Meiendorf Interstadial , recognizable by the sharp decline in birch pollen and the general increase in non-tree pollen such as grasses , sour grasses (Cyperaceae), sweet grasses (Poaceae), mugwort (Artemisia) with an absolute maximum , Thorny moss fern (Selaginella selaginoides), bedstraws (Galium), horsetail (Equisetum), sun rose (Helianthemum), plants that are aquatic in damp locations such as milfoil (Myriophyllum spicatum), black clover (Menyanthes), spawning herbs for (Potaminsthes), as well as groundwater herbs Dock (Rumex) and ribwort (Plantago). Pine trees are now spreading more strongly and willows (especially dwarf willows) and junipers are part of the absolute shrub maximum.

The upper limit of the oldest dryas period and thus the lower limit of the Bölling interstadial is a renewed, striking increase in pollen from tree birch and a sharp decrease in pollen from sun plants (heliophytes).

Cultural history

Several regional traditions can be distinguished among the cultures of the end of the Paleolithic Age . In Denmark and southern Sweden, for example, the penknife groups (12000 to 10800 BC) had established themselves, which mainly hunted reindeer . Even before the beginning of the oldest Dryas period, the Hamburg culture (13500 to 11100 BC) with the Havelte subgroup (from 13000 BC) had developed in the north German lowlands . In southern Germany and in the Paris area , the Magdalenian still existed (16000 to 8000 BC), in Italy and Eastern Europe the epigravettia . Natufien (12300 to 10200 BC), a proto-agrarian cultural stage based on the use of wild cereals such as emmer and double-row barley , emerged in the Levant .

See also

• Bölling-Interstadial
• Meiendorf-Interstadial

Individual evidence

1. ↑ Thomas Litt, Karl-Ernst Behre, Klaus-Dieter Meyer, Hans-Jürgen Stephan and Stefan Wansa: Stratigraphic terms for the Quaternary of the northern German glaciation area. ( Memento of the original from February 5, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Ice Age and Present (Quaternary Science Journal), Vol. 56 (1/2), pp. 7-65. Hanover 2007 ISSN 0424-7116  
2. ↑ ^{a b} Hoek, WZ: Atlas to Palaeogeography of Lateglacial Vegetations - Maps of Lateglacial and Early Holocene landscape and vegetation in The Netherlands, with an extensive review of available palynological data . In: Netherlands Geographical Studies . tape 231 . Utrecht 1997.
3. ^ Lowe, JJ et al .: Synchronization of palaeoenvironmental events in the North Atlantic region during the Last Termination: a revised protocol recommended by the INTIMATE group . In: Quaternary Science Reviews . tape 27 (1–2) , 2008, pp. 6-17 .
4. ↑ van Raden, UJ et al .: High-resolution late-glacial chronology for the Gerzensee lake record (Switzerland): δ18O correlation between a Gerzensee-stack and NGRIP . In: Palaeogeography, Palaeoclimatology, Palaeoecology . 2012.
5. ^ Miallier D. et al .: Revised chronology of the youngest volcanoes of the Chaîne des Puys (French Massif Central) . In: Quaternaire . tape 23 (4) , 2012, p. 283-290 .
6. ↑ Jennifer D. Stanford, Eelco J. Rohling, Sally E. Hunter, Andrew P. Roberts, Sune O. Rasmussen, Edouard Bard, Jerry McManus, Richard G. Fairbanks: Timing of meltwater pulse 1a and climate responses to meltwater injections . In: American Geophysical Union (Ed.): Paleoceanography . 21, No. 4, December 9, 2006, p. 4103. bibcode : 2006PalOc..21.4103S . doi : 10.1029 / 2006PA001340 .
7. ↑ Atkinson, TC et al. a .: Seasonal temperatures in Britain during the past 22,000 years, reconstructed using beetle remains . In: Nature . tape 325 , 1987, pp. 587-593 .
8. ^ Van Geel, B. et al .: Paleoecology and stratigraphy of the Lateglacial type section at Usselo (The Netherlands) . In: Review of Paleobotany and Palynology . tape 39 , 1989, pp. 25-129 .
9. ↑ Hoek, WZ and Bohncke, SJP: Climatic and environmental events over the load termination, as recorded in the Netherlands: a review . In: Netherlands Journal of Geosciences / Geologie en Mijnbouw . tape 81 (1) , 2002, pp. 123-137 .