Archaeologists Discover Underwater Caves - the World’s Oldest Ocher Mines

Updated: Jul 12, 2020

Cave divers in Mexico’s Yucatan peninsula swam for nearly half a mile through water-filled cave systems, winding around spires of rock. Sliding along a narrow passage, they discovered an ancient scene preserved in startling detail: an 11,000-year-old mining site for ocher pigments. Acting as a time capsule, this site provides a rare glimpse into the lives of early humans in the Americas... 

A diver examines a pile of rocks, an ancient navigational marker, inside a 12,000-year-old ocher mine. CINDAQ.ORG

A Startling Discovery

During a cave surveying class led by Fred Devos, students noticed an unexplored tunnel in the Sagitario cave system near Playa del Carmen. Returning later with Sam Meacham, director of the Quintana Roo Aquifer System Research Center (CINDAQ), Devos entered the passageway - a mere 28 inches across - in the spring of 2017. “That was the portal into this whole other side,” recalled Meacham. 

The divers were quickly astonished by the site ahead, one filled with indications of human activity. Trenches marked the chamber floor, and scattered across were broken speleothems - stalagmites or stalactites - once used as makeshift tools. Tidy piles of rocks (pictured above) functioned as markers of a miner’s way. By viewing soot under an electron microscope, researchers concluded that charcoal fragments came from local, high resinous trees - perfect for torchwood. 

“Fred and I immediately just started pointing at all of this stuff,” Meacham says, “It’s not natural, and there’s nothing that could have done this other than humans.” Following their initial dive, Devos and Meacham contacted Eduard Reinhardt of McMaster University to discuss the site. Together, they named it La Mina, Spanish for “the mine.” 

The team confirmed that two other suspected sites in submerged caves - located 20 miles south of La Mina in Quintana Roo - were mining operations as well. According to radiocarbon dates, the trio of mines was in use around 10,000 to 12,000 years ago.

Broken speleothems - once used as ocher extraction tools - seen on the cave floor of La Mina. CINDAQ.ORG

The Importance

Over the last 15 years, archaeologists have found ancient human skeletons in the twisting labyrinths of sinkhole caves in Mexico’s Yucatan peninsula. Famously discovered in 2007, the skeletal remains of a 13,000-year-old Paleoamerican woman, later nicknamed Naia, have piqued the curiosity of archaeologists for years. 

“While Naia added to the understanding of ancestry, growth, and development of these early Americans, little was known about why she and her contemporaries took the risk to enter the maze of caves,”

wrote researchers from CINDAQ. Nine individuals, in addition to Naia, have been identified in the cave system. About 8,000 years ago, rising sea levels around the Caribbean coast submerged the caves, leaving their remains undiscovered until recent years. 

La Mina is one of the Western Hemisphere’s oldest known ocher mining sites. This discovery - according to Roberto Junco Sanchez of Mexico’s National Institute of Anthropology and History - explains pre-Maya human remains like Naia previously found in the submerged cave systems. 

“Now we know that ancient humans did not risk entering this maze of caves just to get water or flee from predators, but that they also entered them to mine,”Junco Sanchez said. 

Deep red undersides of discarded rocks reveal ocher - a treasured crimson mineral. CINDAQ.ORG

Ocher - Vibrant and Versatile 

Red and iron-rich, this mineral was utilized by ancient humans across the globe. In South Africa, the pigments formed vibrant paints in abalone shells some 100,000 years ago. They illuminate handprints on cave walls in Chauvet, France around 30,000 years ago. Ocher is not limited to artistic uses - some civilizations utilized it as a mosquito repellent or adhesive in toolmaking.

In the Americas, early people prized the mineral for use in decorations and rituals. Pigments were used in cave paintings, rock art, burials, and other structures. However, in the caves of the Yucatan, the end goal for ocher mining is unclear. Dr. Spencer Pelton of the University of Wyoming acknowledges the especially powerful attraction of ocher among early inhabitants of the Americas. 

“[Red ocher mining] seems especially important during the first period of human colonization... you find it on tools, floors, hunt sites,” Peloton said. “It’s a substance of great power ...everybody likes shiny red things.”

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