Underwater caves once hosted the Americas’ oldest known ochre mines

Now-submerged Mexican caves hold signs of red pigment extraction as early as 12,000 years ago

A diver collects burned wood from a fire pit in the oldest known ochre mine in the Americas. People extracted red pigment from chambers deep in a now-submerged Mexican cave system between around 12,000 and 10,000 years ago, scientists say.

By Bruce Bower

July 3, 2020 at 2:00 pm

Ancient Americans ventured deep into caves along a stretch of Mexico’s Yucatán Peninsula to mine a red pigment that could have had both practical and ritual uses, researchers say.

Discoveries of mining-related artifacts and digging areas by divers in three now-submerged cave systems indicate that people there removed a natural pigment called red ochre, say archaeologist Brandi MacDonald of the University of Missouri in Columbia and her colleagues. Radiocarbon dates of burned wood from fires used to illuminate mining areas place humans at these sites between roughly 12,000 and 10,000 years ago, making it the oldest evidence of ochre mining in the Americas, the investigators report July 3 in Science Advances.

Previous finds have suggested that ancient Americans used red ochre in many ways, including as an antiseptic, sunscreen, hide-tanning agent and for body painting and other symbolic purposes (SN: 2/12/14).

Floating through the eerie depths of a submerged cave system on the Yucatán Peninsula, divers recovered evidence that ancient people dug up deposits of the red pigment as early as 12,000 years ago when the chambers were dry. The findings make this the oldest known ochre mine in the Americas.

Remnants of ancient pigment mining uncovered by MacDonald’s team raise the possibility that some miners may have died and been left where they perished. Divers previously found at least 10 human skeletons in Yucatán caves dating to as early as around 12,000 years ago, before rising seas inundated the underground chambers (SN: 2/6/20).

In one cave system, an approximately 900-meter-long series of tunnels dubbed La Mina contained extensive evidence of red ochre extraction. Several narrow passages leading into La Mina contained piles of stones and broken pieces of cave growths that miners apparently used as navigation guides. Other broken-off cave growths had been wielded as digging tools. Most of the 352 pits and other intentionally disturbed areas in La Mina contain remnants of ochre deposits, the researchers say. Ochre samples from La Mina were bright red and chemically suitable for making paint, they add.

We summarize the week's scientific breakthroughs every Thursday.