Continental Breakup, Volcanic Emissions May Influence Evolution

New research suggests continental drift dictates volcanic carbon emissions.

The link between dramatic tectonic shifts—the formation and breakup of the supercontinents—and Earth's carbon cycle also has a strong influence on the trajectory of evolution, scientists argue, UPI reported. When researchers from the University of Cambridge analyzed the chemical signatures of carbon and helium emanating from some 80 volcano's scatters about the globe, they found most volcanic emissions are recycled from rather shallow sources.

"This is an essential piece of geological carbon cycle puzzle," Cambridge researcher, Marie Edmonds, said in a news release.

However, scientists believe this was unlikely to be the case in the distant future.

The recent analysis revealed island arc volcanoes tend to emit less carbon overall, but more carbon from sources deep in the mantle, while continental volcanoes emit more carbon, a majority from shallow sources. As continents formed and broke up over time, researchers hypothesize, the balance of power between continental and island arc volcanoes shifted back and forth, transforming Earth's carbon cycle. Island arc volcanoes dominated during the period of continental formation but when continents split apart, continental volcanoes gain power.

These shifts are reflected in the isotopes of geologic strata. Until now, scientists thought changes in atmospheric oxygen were the sole factor influencing isotopic carbon ratios in limestone.