Scientists say they will drill deep into a Wyoming basin in search of clues to a massive release of carbon dioxide into the atmosphere 55 million years ago. Researchers say the Earth belched up a massive amount of CO2 into the atmosphere in that ancient period -- an amount equivalent to burning all the petroleum and other fossil fuels that exist today -- in an environmental anomaly called a hypothermal event. “And we don\'t know where it came from,” Will Clyde, University of New Hampshire associate professor of geology, said. “This is a big part of the carbon cycle that affected the climate system, and we don\'t understand it.” This month, a team of 27 scientists from 11 institutions will drill a series of cores into the stratified layers of rocks in the Bighorn Basin of Wyoming in hopes of gaining a better understanding of this mystery and possibly of current and future global climate change, a university release said Tuesday. Drilling cores about 500 feet into the sediment will provide pristine core samples for more precise geochemical analyses, Clyde said. “It will help us better understand the long-term carbon cycle of the Earth,” he said. “Hopefully, by looking at the past, we will better understand prospects for the long-term climate cycle that may or may not become our future.”