Human use of ochre spans 200,000 years or more to the very earliest days of modern homo sapiens, to the origin art, science and environmental control
It was a simple stroke of serendipity that led to the discovery in Mexico of the earliest underground ochre mine in the New World, which a new journal article describes as a vast prehistoric industrial complex as much as 12 millennia old, where Paleonindians prospected for the valuable red iron-rich mineral that is a major factor in human evolution.
It began in 2017, when a Canadian scuba diving instructor went through a tight passage to become the first person ever to enter an unknown chamber in the cave complex in Quintana Roo, on the eastern Yucatan peninsula, on Mexico’s Caribbean coast.
Fred Devos had been teaching an underwater cave survey class, stringing new guide lines and estimating the volume of cave passages by measuring out from the line to the wall, when a student taking a measurement noticed a tunnel with no exploration line leading into it.
Soon after, Devos and diver Sam Meacham swam their way into the blackness. Their exploration took them first up into an air dome and back down into the water, then through a tight restriction, through which Devos was likely the first person to pass in modern times.
“It’s almost as if we passed through a portal,” said Meacham, a Texan diver who, with Devos, runs an organization in Mexico to study and conserve the local underground water systems.
Water is their primary interest, but they come across all kinds of things, submerged here since the once-dry cave flooded about 8,000 years ago.
“There’s all sorts of stuff in these caves,” Meacham said in an interview. Over the years they had noticed weird things out of place, like rocks piled on top of each other, things that did not look natural but had no obvious explanation other than people. Other caves nearby had yielded human remains, but they seemed more the exception than the rule, people who had somehow died on site, such as Naia, the previously reported 13,000 year old skeleton of a teenage girl.
“We knew people were in there,” Meacham said. But it was not until they found this new chamber, and many more beyond, that they saw the full scale of this prehistoric underground human enterprise.
“We started seeing widespread destruction in what would have been a pristine cave,” Meacham said. “It must be ingrained in human nature to pile rocks on top of each other. There was no other way it could have got there other then a human stacking it on top.”
In places, the floor of the cave had been bashed open to reveal the ochre layer beneath, and the hole extended by smashing rocks, with breakage piled up at the sides. There were pits, stone tools, piles of debris, cairns to mark direction, hearths for charcoal, soot-blackened spots on the ceiling.
It was an ochre mine, or used to be, back when this cave was dry and filled with the stench of wood fires for light, the closeness of humanity pushing itself into the farthest subterranean reaches of planet Earth.
This is detailed in new research in the journal Science Advances, led by Brandi MacDonald of the University of Missouri, with Eduard Reinhardt of McMaster University in Hamilton, and Meacham and Devos among others.
The research presents “uniquely preserved evidence indicating that people were exploring underground cave systems to prospect and mine red ochre, an iron oxide earth mineral pigment widely used by North America’s earliest inhabitants.”
The scale of the thing is what makes it astonishing, spread over three cave systems — known as Camilo Mina, Monkey Dust, and Sagitario — a few kilometres from the present day Caribbean coastline. This ochre mine was, as the authors describe, a “regional-scale activity that was sustained over multiple generations.”
The cave is thought to have been dry from the Last Glacial Maximum more than 20,000 years ago, to when it flooded, perhaps as recently as 8,000 years ago.
Humans were already well established in North America, having come perhaps 14,000 years ago from the north. In 2018, the discovery of two infants ceremonially buried in Alaska 11,500 years ago was held up as further evidence for the theory that humans, after becoming anatomically modern in Africa and spreading across Asia, slowly and fitfully migrated from Siberia via Alaska into all of the Americas, some via Pacific coastal waters, others through inland routes depending on glacial activity.
Ochre, a catch-all term for various sorts and colours of iron oxide mixed with clay and sand, figures into every part of this human story.
Human use of ochre spans 200,000 years or more to the very earliest days of modern homo sapiens, to the origin art and science of creative expression and environmental control. Humans learned to get it, and to use it, and ever since it has been a clue to symbolic thinking and social behaviour
It is there in Blombos cave in South Africa, where pieces of ochre pigment along with carved bone tools and decorative etchings seem to indicate homo sapiens was thinking abstractly as early as 70,000 years ago. It was also a defining cultural practice of the Beothuk Indigenous people of Newfoundland, and may be the origin of the notion of “Red” Indians, which survives today in the name of a professional football team.
One of the abiding questions of anthropology is what ochre was primarily used for, and why it so reliably followed human migration out of Africa, through Asia, as far as Australia, Europe, the Americas.
The new paper sketches the question of whether ochre was prized for utilitarian reasons (such as sunscreen, antiseptic, pesticide, purgative, hide tanning) or ceremonial reasons (mortuary practices, paint, when mixed with animal fat).
“Whether ochre procurement or use by Paleoindian groups and their Old World predecessors constitutes evidence for ritual behavior or utilitarian purposes remains an ongoing anthropological discussion, yet consensus suggests that the two are not mutually exclusive,” the paper reads.