Cored through sediment layers at the bottom of a lake in northeastern Siberia, the record shows what happened when a meteorite smashed into the planet 3.6 million years ago and water filled the resulting crater to form the lake, ScienceNews.org reported Wednesday.
Lake El'gygytgyn lies 60 miles north of the Arctic Circle and 225 miles from the nearest inhabited town. The 7-mile-wide lake is too rough and windy in the summer to be drilled from a floating rig, so researchers took on the challenge of drilling in the dead of winter from an ice platform.
"The sheer logistics prevented anyone from doing this before," Julie Brigham-Grette, a geologist at the University of Massachusetts, said.
Analysis of the lake cores is revealing details of how the arctic landscape warmed and cooled during the past several million years, and that it was probably 18 to 25 degrees warmer than today, and forested when the meteor hit millions of years ago.
"We're really pleased that we have a complete record of that entire time period," Brigham-Grette said.