Archaeologists have discovered what appears to be the oldest mine in the Americas, a quarry in eastern Wyoming where prehistoric humans sourced red ocher some 13,000 years ago.
Red ocher, also known as hematite, was a versatile substance for the ancients, who employed it in ritual ceremonies as bug repellant or sunscreen, and for medicinal use. It was also hugely important for prehistoric artists, for whom it was a pigment for painting cave art.
The discovery of the quarry, uncovered at a site known as Powars II, was published this month in the academic journal Proceedings of the National Academy of Sciences by a team at the University of Wyoming.
“We have unequivocal evidence for use of this site by early Paleoindians as long as 12,840 years ago and continuing by early Americans for about 1,000 years,” Wyoming state archaeologist Spencer Pelton, the paper’s lead author, said in a statement.
A Clovis point discovered from the Powars II site. Photo by Spencer Pelton, courtesy of the University of Wyoming.
In excavations of a new trench at Powars II carried out between 2017 and 2020, archaeologists found antlers and other animal bones that had been used to extract the red ocher from the earth.
Radiocarbon dating techniques determined that humans first began digging the mine from 12,840 to 12,505 years ago, and that the site was active for hundreds of years. Humans even returned after a hiatus of about a century, resuming their mining activities.
The findings confirm theories proposed by archaeologist George Frison, who first began studying the Powars II site in 1986, helping save it from a 20th-century mining project. (He died in 2020, shortly after the excavations concluded, and is still credited as a coauthor of the paper.)
Prior to the most recent dig, artifacts discovered at the Powars II site included Clovis points made by early inhabitants of North America, tools, and shell beads—and archaeologists expect more finds as excavations continue in the years to come.
“Beyond its status as a quarry, the Powars II artifact assemblage is itself one of the densest and most diverse of any thus far discovered in the early Paleoindian record of the Americas,” Pelton added.
Red ocher was commonly used across the Americas, and has been found at many ancient burial grounds, campsites, and hunting grounds. But only five red ocher quarries have ever been identified in the Americas, and Powars II is the first one found north of southern Mexico.
“Red paint is the oldest form of symbolic expression,” Pelton told the Gillette News Record. “But there’s just not much red pigment in America.”