Heinrich event

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Three temperature records. the Greenland ice core project sequence (red) showing the Younger Dryas event at around 11.0 ka BP. The vertical axis shows changes in O18 (oxygen 16), which is a temperature proxy for the water which ended up in the ice core.

Heinrich events occurred during the coldest point of Bond Cycles in which many icebergs were discharged into the North Atlantic and melted.

Evidence for this can be found in the north Atlantic sediment cores which show poorly sorted, angular and contain rocks. These were originally in the icebergs but dropped to the bottom of the ocean when the icebergs melted.[1]

Heinrich events are a possible trigger to the onset of mini ice ages which follow a long period of thaw. An example might be the Younger Dryas, a brief cold period from about 12.8 thousand years ago to about 11.5 thousand years ago.[2][3]

The Younger Dryas stadial is thought to have been caused by the collapse of the North American ice sheets, although rival theories have been proposed.

References[change | change source]

  1. Holden, J 2008. An Introduction to physical geography and the environment. 2nd ed. Essex: Pearson Education Limited. 576, 716.
  2. Berger, W. H. (1990). "The Younger Dryas cold spell — a quest for causes". Global and Planetary Change 3 (3): 219–237. doi:10.1016/0921-8181(90)90018-8 .
  3. Muscheler, Raimund et al. (2008). "Tree rings and ice cores reveal 14C calibration uncertainties during the Younger Dryas". Nature Geoscience 1 (4): 263–267. doi:10.1038/ngeo128 .