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Science

A Billion Years Ago Antarctica was linked to North America

New research from an international team of scientists has provided the strongest yet evidence that Antarctica and North America were once part of the same continent 1.1 billion years ago, well before the super continent of Pangaea was formed.

Coats Land with its only rock outcrops, Littlewood (L) and Bertrab (B) nunataks.

“I can go to the Franklin Mountains in West Texas and stand next to what was once part of Coats Land in Antarctica,” said Staci Loewy, a geochemist at California State University, Bakersfield, who led the study. “That’s so amazing.”

Loewy and her colleagues discovered rocks from the Franklin Mountains in West Texas and from Coats Land in Antarctica that carried the exact same composition of lead isotopes.

Earlier analysis had already shown that rocks from the two locations were the exact same age and of the same chemical and geologic properties.

The work was published online ahead of a print release in the journal Geology, and supports the case for the idea of the supercontinent Rodinia.

The North American Mid-continent Rift System, which spans the subsurface length of the continent from the Great Lakes through Minnesota, Iowa, Nebraska, Kansas and Oklahoma to the Franklin Mountains near El Paso, Texas, where related rocks are exposed. This Rift System is supposed to represent an aborted tectonic split of the continent.

Loewy and her colleagues found rocks from Coats Land reflect a previously unknown continuation of the North American Mid-continent Rift System.

All of this took place prior to the opening of the Pacific Ocean basin, the hypothesized “Snowball Earth” glaciations, and the rise of multi-cellular life.

Source: The Geological Society of America
Image Source: Ian Dalziel via The Geological Society of America




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