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 In glaciology, an ice cap is a mass of ice that covers less than of land area (usually covering a highland area). Larger ice masses covering more than are termed ice sheets. Description Ice caps are not constrained by topographical feat ...

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 a ...

separating opposing flow directions of ice, analogous to a

water divide A drainage divide, water divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single ...

. Ice divides are important for geochronological investigations that use

ice core An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ...

s, 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 operates at ice divides, creating anticlines 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, Marine radar, ships, spacecraft, guided missiles, motor v ...

-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 gas A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...

es 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, 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 The Antarctic ice sheet is one of the two polar ice caps of Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. It covers an area of almost and ...

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 (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