Dalziel

UT researchers have discovered volcanic rocks in the south Atlantic that could change how scientists understand the formation of Antartica’s ice sheet.

Researchers say the volcanic rocks, an unexpected result of a simple test on ocean floor, were part of a chain of volcanic islands that existed about 28 million years ago. Researchers previously believed the Antarctic Circumvent Current was the sole cause of the glaciers in Antartica, but the presence of the islands means the current could not have been formed at that time.

This means researchers will have to find a new explanation for how Antartica’s glaciers formed, said geoscience professor Ian Danziel, the leader of the expedition.

“We went out to look at a piece of the ocean floor that nobody understands, and we expected to pick up normal ocean floor rocks,” Danziel said.  “But instead it was like, whoa these are volcanic rocks!”

The site of the volcanic remnants is in the Scotia Sea of the South Atlantic, and resembles the volcanic arc of the South Sandwich Islands, Danziel said.

One of Dalziel’s colleagues, research scientist Lawrence Lawver, said the research was simple science. 

“We want to increase our understanding on how the area developed overtime,” Lawver said.

Lawver said a great deal of the work in the study, especially in tectonics, came from Peter Barker of the University of Birmingham. The professor passed away a year ago, before the dig was over.

Dalziel said they have presented their work in journal of the Geological Society of America and have recieved a positive response. 

“There were no wild cards of disapproval,” Dalzeil. “Everyone has known that this piece of ocean floor is rather strange.”

The timing of the volanoes helps scientists understand the effects of global climate in the area and raises the possibility that a land bridge existed between Antartica and South America. This could mean that animals traveled between the two continents later than previously thought, Dalzeil said. 

There were only four locations Dalziel and his colleagues retrieved the submerged pieces of ocean floor. With funding from the National Science Foundation, Dalziel said researchers plan to return to the location, an area the size of France, to continue their research in the future. 

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