June 17, 2009

Ocean core provides ancient climate record

U.S. scientists have used deep ocean sediment to reconstruct an ancient climate record dating to more than 500,000 years.

Ohio State University researchers said the sediment -- trapped within the top 65.6 feet of a 1,312-foot sediment core drilled in 2005 in the North Atlantic Ocean -- has provided new information about the four glacial cycles that occurred during that period.

We've now generated a climate record from this core that has a very high temporal resolution, one that is decipherable at increments of 100 to 300 years, post-doctoral fellow Harunur Rashid of OSU's Byrd Polar Research Center said. What we have is unprecedented among marine records.

While climate records from ice cores can show resolutions with individual annual layers, the researchers said ocean sediment cores are greatly compressed with resolutions sometimes no finer than millennia.

The research, which included scientists from the University of South Florida, the University of Bremen in Germany and the National Laboratory of Energy and Geology in Portugal, was presented this week at the Byrd Center during the Chapman Conference on Abrupt Climate Change.