Ice divide

An ice divide is the boundary on an ice sheet, ice cap or glacier separating opposing flow directions of ice, analogous to a water divide. Such ice divides are important for geochronology investigations using ice cores, because such coring is typically made on top of a dome of an ice sheet to avoid interference caused by horizontal ice movement. Ice divides are used for looking at what the atmosphere was like in history. The ice is very accurate because instead of shifting horizontally like normal ice, it moves vertically downward with time trapping gases into its layers. Scientist find these ice divides and take ice cores from them, which are typically long cylinder poles of ice, and evaluate them. Once they have these ice cores, they are able to look through it and find elements that the snow and ice carried down with it during that time period such as sulfate, nitrate, and other ions. These ice cores are important in determining how our atmosphere has changed for the better or worse, and how we can fix it such as the greenhouse effect which discovered when scientist found how much more greenhouse gasses was in our atmosphere than there was in the past.