DO1 (paleoclimate)

DO1 is the second of a total of 26 Dansgaard-Oeschger events in the last glacial period . It took place at the beginning of the Meiendorf interstadial around 12,400 years BC. Chr. Instead.

characterization

Ice cores from Greenland document a sharp rise in the δ ¹⁸ O values and, consequently, a rapid rise in temperature in the Meiendorf interstadial. The ice core of Dye-3 in the south of Greenland shows a rapid rise in values from - 34 ‰ to - 30 ‰ within around 100 years, that of GISP2 from - 40 to -35 ‰, that of GRIP from - 39.5 to - 34.5% (both in the center of the ice sheet at 72 ° north latitude) and that of NGRIP in northern Greenland from -41 to -36 ‰. The difference is therefore 4 to 5 ‰ within this very short period of time. The increase in oxygen isotopes in GISP2 is equivalent to a temperature increase of 13 ° C; the annual mean at this drilling station, for example, rose from -45 ° C to -32 ° C.

Drill cores from the Antarctic such as Byrd hardly reveal the DO1 anomaly at all, rather they document a fairly steady rise in temperature in the direction of the Meiendorf Interstadial.

Associated with the DO1 event are increases in the concentration of greenhouse gases such as methane (significant) and carbon dioxide (less significant).

DO1 is likely to be the most important Dansgaard-Oeschger event, as its maximum value almost reached the level of the Holocene peak values (- 34 ‰).

Temporal position

Temporal classification of DO1 during the last 47,500 years of geological history

The positive heat anomaly DO1 follows the cold trough of the Heinrich event H1 , which covered the period 16000 to 13000 BC. And its minimum at 14000 BC. Chr. Lies. Hemming (2004) sets this minimum a little earlier at 14800 BC. Chr.

DO1 can be used to define the beginning of the relatively warm Meiendorf interstadial and thus lies in the period from 12500 to 12300 BC. Chr.

The time difference to the previous DO2 (21300 to 20500 BC) , which was already in the last glacial maximum , is (averaged) 8500 years. This corresponds roughly to six 1470-year cycles.

DO1 is followed by the sudden increase in oxygen isotopes and temperature at the Younger Dryas / Holocene border (9700 BC), which is often viewed as the Dansgaard-Oeschger event and is referred to as DO0 . The time lag to this event is 2600 years or almost two 1470 year cycles.

Individual evidence

↑ J. Alvarez-Solas et al .: Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes . In: Climate of the Past . tape 7 , 2011, p. 1297-1306 .
↑ Hemming, SR: Heinrich events: massive late Pleistocene detritus layers of the North Atlantic and their global climate imprint . In: Rev. Geophys. tape 42 , 2004, doi : 10.1029 / 2003RG000128 .

[1] J. Alvarez-Solas et al .: Heinrich event 1: an example of dynamical ice-sheet reaction to oceanic changes . In: Climate of the Past . tape 7 , 2011, p. 1297-1306 .

[2] Hemming, SR: Heinrich events: massive late Pleistocene detritus layers of the North Atlantic and their global climate imprint . In: Rev. Geophys. tape 42 , 2004, doi : 10.1029 / 2003RG000128 .