Archaeologists Uncover Oldest Rock Carvings in North America

Scientists may have tracked down the oldest carvings in North America. Researchers have discovered petroglyphs etched into several boulders in western Nevada that date back to at least 10,500 years ago and may be as old as 14,800 years.

Petroglyphs are pictogram and logogram images created by removing part of a rock surface by incising, picking, carving or abrading. In this case, the carvings depict a series of vertical, chain-like symbols and a number of smaller pits deeply incised with a type of hard rock scraper. While these carvings don't depict any people or animals, though, they do reveal a little bit more about the area itself.

The carvings were made before a time when the Winnemucca Lake subbasin, a body of water that connected the now-dry Winnemucca Lake and the existing Pyramid lake, reached the specific elevation of 3,960 feet. This is the maximum height the lake system could have reacted before excess water spilled over Emerson Pass to the north, which is when the boulders would have been submerged and inaccessible for carving.

During their study, the scientists found a white layer of carbonate made of limestone precipitated from the ancient, overflowing Winnemucca. This layer coated some of the petroglyph carving near the base of the boulders. In order to learn exactly how old the petroglyphs were, the scientists then sampled the carbonate into which the petroglyphs were incised and the carbonate that coated the petroglyphs at the base of the limestone boulder. It turned out that the carbonate layer underlying the carvings dated to roughly 14,800 years ago.

"Prior to our study, archaeologists had suggested these petroglyphs were extremely old," said Larry Benson, one of the researchers, in a news release. "Whether they turn out to be as old as 14,800 years ago or as recent as 10,500 years ago, they are still the oldest petroglyphs that have been dated in North America."

Currently, the archaeologists have no idea what the petroglyphs mean. Yet they are stunning; many of them look like multiple connected sets of diamonds, and some look like trees or veins in a leaf. No doubt with future studies, researchers may be able to determine exactly why these carvings were etched into the stone. For now, it's enough that they exist.

The findings are published in the Journal of Archaeological Science.