From: Roger Greenway, ENN
Published November 3, 2009 06:46 AM

Ohio State Glaciologist Team Gets Important Ice Cores in Andes

Ice cores are important tools to identify Earth’s past climate. They enable us to peer back in time to identify species of insects trapped in ice as well as isotopes oxygen and dust particles that were deposited at various time in the past. The ratio of oxygen isotopes in the ice allows researchers to determine whether temperatures were warmer or cooler when the snow that eventually turned to ice was deposited on the glacier. The dust content gives scientists clues about the rate of precipitation at the site. The thicker the core (longer cores) the longer into the past we can see.

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Researchers from Ohio State spent two months this summer high in the Peruvian Andes and brought back two cores, the longest ever drilled from ice fields in the tropics. Glaciologist Lonnie Thompson said that this latest expedition focused on a yet-to-be-named ice field 5,364 meters (17,598 feet) above sea level in the Cordillera Blanca mountain range.

The researchers hiked to a col, or saddle, between two adjacent peaks — Hualcán and Copa — set up camp and used a ground sensing radar to map the ice depths across the glacier . They then drilled two cores through the thickest part of the ancient ice to bedrock, capturing the entire climate record at this site.

One of the cores measured 196 meters (643 feet) while the other totaled 189 meters (620 feet). Thompson said that the initial visual inspection of the cores showed that they contained a number of insects and plant materials that may have blown up onto the glacier from the Amazon Basin.

"I’ve never seen so many of what appear to be plants and insects in any of the ice cores we've previously drilled," he said. "We should be able to identify them and use carbon-14 to date them. This will help us determine the age of the ice in the core. These cores also contain very distinct bubble-free, or clear, ice near the bottom which suggests very warm conditions in the past."

For  more information: http://researchnews.osu.edu/archive/ltnewcore.htm

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