Cesty do hlubin zamrzlého času
Journeys into the depth of frozen time by Petr Pokorný.
Cores through the polar ice sheets provide a remarkable record of past environmental conditions. Ice coring evolved as a specific science since 1960s through pioneering effort of scientists from USA and other nations. Snow accumulating on polar plateaus of Antarctic and Greenland does this in a regularly ordered fashion that preserves a stratigraphic sequence accessible by drilling vertical borings into the ice. Collecting these cores is a specialized engineering challenge. Because ice is a deformable material, and flows, ice coring locations must be chosen carefully to extract the most reliable information. Deep cores require large equipment, and fluid-filled boreholes to avoid freezing and collapse of the hole. The deepest cores are collected during multi-year campaigns and provide views more than 700 000 years deep into the past.