An ice divide is the boundary on an

ice sheet In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at La ...

, ice cap or

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

separating opposing flow directions of

ice Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaqu ...

, analogous to a water divide. Ice divides are important for geochronological investigations that use ice cores, since such coring is typically made at highest point of an ice sheet dome to avoid disturbances arising from horizontal ice movement. Ice divides are used for looking at how the atmosphere varied over time. Coring at dome peaks increases precision of reconstructions as it is the place where horizontal motion is at its least. The

Raymond Effect Raymond Effect is a flow effect in ice sheets, occurring at flow divides, which gives rise to disturbances in the stratigraphy, showing unusual arches or anticlines called ''Raymond Arches''. The stratigraphy is detected by radio-echo sounding. Th ...

operates at ice divides, creating

anticlines In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the l ...

in the

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...

-detected isochrones, allowing greater capture of older ice when coring. Analysis of ice cores relies on the downward motion of ice, trapping changes of atmospheric gases through time into its layers. Scientist locate ice divides and take ice cores from them, which are typically long cylindrical poles of ice, and analyse them to find chemical elements that the snow and ice transported during that period, e.g. sulfate, nitrate, and other ions. Ice cores are important in determining how our atmosphere has changed, and how we can remedy changes such as the

greenhouse effect The greenhouse effect is a process that occurs when energy from a planet's host star goes through the planet's atmosphere and heats the planet's surface, but greenhouse gases in the atmosphere prevent some of the heat from returning directly ...

; scientists found more greenhouse gases were in our atmosphere at present than in the past. Scientists from around the United States came together to find the best ice divide in order to go the further into the past. They founded the WAIS project, which is funded by the United States National Science Foundation, and is run by scientists from many organizations e.g.

National Ice Core Laboratory The National Science Foundation Ice Core Facility (NSF-ICF), known as the National Ice Core Laboratory (NICL) before 2018, is the primary repository for ice cores collected by the United States. The facility is located at the Denver Federal Cente ...

, Ice Drilling Design and Operations (IDDO), and over fifty universities. The WAIS project is located in West Antarctica, and the goal is to look into the evolution of the Antarctic ice sheet and

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

over the past 100,000 years. The

West Antarctic Ice Sheet The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as ...

(WAIS) is better than other ice divides because of the amount of snow it gets, which means that the layers of ice are thicker. This larger layer thickness means there to be a smaller off-set between the ages of the ice and that of the air and gases trapped inside, allowing scientists to give more precise statements about how the atmosphere varied in the past. The success of the WAIS project has educated scientists around the world as to how the atmosphere of Earth has changed dramatically over 100,000 years.

References

Water ice Glaciology {{topography-stub