Paleo Slide Set: Polar Ice Cores
Deep drilling at Vostok

Deep drilling at Vostok was begun by the Soviets in 1980. After five years of coring, 
a stuck drill brought the 3G core, whose shelter is shown here, to a halt. Chemical analysis 
of air bubbles trapped in the 160,000 year record contained in this 2202 m core gave scientists 
their first long look at the past composition of Earth's atmosphere. 

Photo Credits:
Todd Sowers 
LDEO, Columbia University, Palisades, New York.