What caused the Dansgaard-Oeschger events?
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).
How many events are in Dansgaard-Oeschger?
25
Scientists Willi Dansgaard and Hans Oeschger first reported the Dansgaard-Oeschger (D-O) events in Greenland ice cores. Each of the 25 observed D-O events consisted of an abrupt warming to near- interglacial conditions that occurred in a matter of decades and was followed by a gradual cooling.
When was 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 are Dansgaard-Oeschger oscillations?
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 is the cause of Heinrich events?
Hunt & Malin (1998) proposed that Heinrich events are caused by earthquakes triggered near the ice margin by rapid deglaciation.
What do Heinrich events tell us about the last glacial period?
Heinrich events are clearly observed in many North Atlantic marine sediment cores covering the last glacial period; the lower resolution of the sedimentary record before this point makes it more difficult to deduce whether they occurred during other glacial periods in the Earth’s history.
What are Heinrich layers?
Heinrich layers North Atlantic sediments that have a high ratio of debris carried by ice to Foraminiferida shells and thus record episodes of major iceberg release or surges in the Laurentide ice sheet. A Dictionary of Earth Sciences.
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