Ohio State University Professor Lonnie Thompson, who led the two-month summer expedition, said the ice cores were removed from a yet-to-be-named ice field 17,598 feet above sea level in an ice field across a Cordillera Blanca mountain range glacier.
One of the cores measured 643 feet, while the other totaled 620 feet.
Thompson said his team did a preliminary analysis for oxygen isotopes and dust particles from a 33-foot section of the core. He said the results confirmed the core contains an annually resolvable record of the climate conditions at the site.
"This was the last opportunity anyone will have to drill at this site," Thompson said. "The warming temperatures there cause melting that compromises the quality of records preserved in the ice. Any future drilling efforts will have to be at colder, and higher, elevations to minimize the impact of melting that can obscure the climate record. Unfortunately there are very few good drill sites above 17,598 in the Cordillera Blanca."