The findings were reported in this week’s edition of Science.
The study is important, experts say, because it documents the Earth’s response to the release of large amounts of greenhouse gases ?carbon dioxide and methane ?into the atmosphere, and definitively links a major volcanic event with a period of global warming.
"There has been evidence in the marine record of this period of global warming, and evidence in the geologic record of the eruptions at roughly the same time, but until now there has been no direct link between the two," said Robert A. Duncan, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University and one of the authors of the study.
Other authors are Michael Storey, from Roskilde University in Denmark, and Carl C. Swisher, from Rutgers University.
The Paleocene-Eocene thermal maximum, or PETM, was a period of intense warming that lasted roughly 220,000 years. In addition to the warming of sea surface waters, this event ?characterized by scientists as a "planetary emergency" ?also greatly increased the acidification of the world’s oceans and led to the extinction of numerous deep-sea species.
Warming periods in Earth’s history are of interest as analogs to today’s climate change, Duncan said.
The international science team was able to link the PETM with the breakup of Greenland from northern Europe through analyzing the ash layers deposited toward the end of the peak of the volcanic eruptions. Using chemical fingerprints and identical ages, they were able to positively match ash layers in east Greenland with those in
Source:Oregon State University