What were the effects of the Younger Dryas?
Younger Dryas, also called Younger Dryas stadial, cool period between roughly 12,900 and 11,600 years ago that disrupted the prevailing warming trend occurring in the Northern Hemisphere at the end of the Pleistocene Epoch (which lasted from 2.6 million to 11,700 years ago).
What is the significance of the Younger Dryas?
The Younger Dryas is a period significant to the study of the response of biota to abrupt climate change and to the study of how humans coped with such rapid changes.
What happened during the Younger Dryas climate event?
The Younger Dryas occurred during the transition from the last glacial period into the present interglacial (the Holocene). During this time, the North American, or Laurentide, ice sheet was rapidly melting and adding freshwater to the ocean.
What caused Dansgaard Oeschger?
The events may be caused by an amplification of solar forcings, or by a cause internal to the earth system – either a “binge-purge” cycle of ice sheets accumulating so much mass they become unstable, as postulated for Heinrich events, or an oscillation in deep ocean currents (Maslin et al.. 2001, p25).
Was the Younger Dryas triggered by a flood?
It is widely believed that this cold event was triggered by a flood of fresh water that poured into the northern Atlantic (1) and disrupted the thermohaline ocean circulation (2).
When did Dansgaard-Oeschger events occur?
Although some scientists note that there may have been up to 25 D-O events during the most recent 120,000 years, detailed analyses of the most accurately dated Greenland ice cores show that 13 D-O events occurred between 11,600 and 45,000 years ago, with an average periodicity of 1,470 years.
When were Dansgaard-Oeschger events?
Dansgaard-Oeschger cycles typically began with a sudden Greenland warming of 10–15 °C within several decades and persisted for about 500 to more than 2000 years. Thus far, 25 events have been identified with an apparent 1600-year periodicity.
What is the Younger Dryas boundary?
Multiple meteor air bursts and/or impacts are claimed to have produced the Younger Dryas (YD) boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at more than 50 sites across about 50 million km2 of Earth’s surface.
When was the 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, but its duration is agreed to have been around 200 years.
Is Dansgaard-Oeschger a global event?
Dansgaard-Oeschger event, also called D-O event, any of several dramatic but fleeting global climatic swings characterized by a period of abrupt warming followed by a period of slow cooling that occurred during the last ice age.
What are Dansgaard-Oeschger oscillations?
Dansgaard-Oeschger (D-O) cycles are oscillations of the climate system during the Wisconsinan glacial, where the climate switched between a cold glacial climate and a “warm” glacial climate.
What caused the 8.2 ka event?
The northern hemisphere experienced an abrupt cold event ~ 8200 years ago (the 8.2 ka event) that was triggered by the release of meltwater into the Labrador Sea, and resulting in a weakening of the poleward oceanic heat transport.
Are the Dansgaard–Oeschger events globally synchronous?
Although the effects of the Dansgaard–Oeschger events are largely constrained to ice cores taken from Greenland, there is evidence to suggest that D-O events have been globally synchronous. A spectral analysis of the American GISP2 isotope record showed a peak of [ 18 O: 16 O] abundance around 1500 years.
What is the Dansgaard-Oeschger cycle?
Each DO cycle represented in the Greenland temperature record has been linked with a large-scale reorganization of the atmospheric circulation around the Northern ice sheets. Dansgaard-Oeschger cycles typically began with a sudden Greenland warming of 10–15 °C within several decades and persisted for about 500 to more than 2000 years.
What caused the Dansgaard–Oeschger events in Antarctica?
Ice core evidence from Antarctic cores suggests that the Dansgaard–Oeschger events are related to the so-called Antarctic Isotope Maxima by means of a coupling of the climate of the two hemispheres, the Polar see-saw.
What is the ISBN for the Younger Dryas impact hypothesis?
ISBN 9781118704325. ^ Daulton, TL; Amari, S; Scott, AC; Hardiman, MJ; Pinter, N; Anderson, R.S. (2017). “Comprehensive analysis of nanodiamond evidence reported to support the Younger Dryas Impact Hypothesis”.