A landmark of piled stone and broken speleothems left 10,000-12,000 years ago left underwater in Yucatan.

Stones and broken cave formations were piled into a marker by prehistoric people 10,000 to 12,000 years ago, probably while they were looking for ochre in a cave in what is now Mexico. Credit: CINDAQ.ORG


Why ancient people pushed deep into Mexico’s pitch-black caverns

Early residents of the Yucatán Peninsula mined a precious pigment from a vast labyrinth of subterranean passages.

Prehistoric people ventured deep into a vast network of twisting caverns in what is now Mexico to extract red ochre, a widely used pigment.

Over the years, divers have found human bones in the now-submerged cave system on the Yucatán Peninsula, but scientists didn’t know what had compelled the area’s early inhabitants to explore the pitch-black tunnels and chambers. The discovery of vibrant, high-purity ochre deposits might have solved that mystery.

Brandi MacDonald at the University of Missouri in Columbia and her colleagues identified 352 distinct features in the subterranean passages that showed evidence of mining. Using techniques including the radiocarbon dating of charcoal deposits, the authors suggest that the area was mined for some 2,000 years; activity stopped about 10,000 years ago.

The scale of the mining operations means that a considerable amount of the mineral was probably unearthed in the caves. Ancient peoples around the world prized ochre for artistic, medicinal and ceremonial purposes, but the lack of above-ground archaeological evidence in the Yucatán means researchers do not know how people there used the hard-won pigment.