How to calculate age using carbon dating
Soviet ice drilling projects in Antarctica include decades of work at Vostok Station, with the deepest core reaching 3769 m.
The weight above makes deeper layers of ice thin and flow outwards.
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, and an ice core contains ice formed over a range of years.
These include soot, ash, and other types of particle from forest fires and volcanoes; isotopes such as beryllium-10 created by cosmic rays; micrometeorites; and pollen.
The lowest layer of a glacier, called basal ice, is frequently formed of subglacial meltwater that has refrozen.
Below this depth, electromechanical or thermal drills are used.