SAN FRANCISCO (CBS SF) — Australia and Antarctica may have once been next door neighbors with California and Arizona, according to new findings by USGS scientists.

Mineral age data from ancient sedimentary rocks of Arizona and New Mexico was studied, and the scientists found that the deposits were approximately 1.6 to 1.5 billion years old, “an age range that does not match any known geologic age provinces in the entire western United States.”

They found that the age data matched well known ages of districts in Australia, and Antarctica.

The scientists suggest that “the North American sedimentary basins were linked to sediment sources in Australia and Antarctica until the breakup of the supercontinent Columbia.”