6,000-Year-Old Submerged Cave Bridge Discovered in Spain’s Mallorca Shows When Mediterranean Was Settled

New research of a submerged bridge inside Genovesa Cave reveals humans lived on the Spanish island of Mallorca in the Mediterranean Sea much earlier than believed. Photo: R. Landreth/CNN

A recently analyzed submerged bridge in Genovesa Cave on the Spanish island of Mallorca is reshaping scientists’ understanding of when humans first settled the islands of the western Mediterranean Sea.

This ancient stone structure, extending 25 feet in length, has been pivotal in demonstrating that human activity on one of the Mediterranean’s largest islands predates prior estimates, CNN reports.

This could significantly narrow the historical gap between human settlements in the eastern and western parts of the Mediterranean.

Published in the journal Communications Earth & Environment, a new study presents findings that suggest the bridge was constructed nearly 6,000 years ago.

The researchers, led by Bogdan Onac, a professor in the School of Geosciences at the University of South Florida, utilized a combination of geological and archaeological methods to date the bridge.

They focused particularly on a “bathtub ring” and mineral formations on the bridge which were crucial in determining its age.

“The presence of this submerged bridge and other artifacts indicates a sophisticated level of activity, implying that early settlers recognized the cave’s water resources and strategically built infrastructure to navigate it,” professor Onac says.

The construction of the bridge from large, heavy limestone blocks, some spanning over four feet, remains a topic of interest, especially considering the unclear mechanisms ancient humans would have had at their disposal to build such a structure.

It is believed the bridge was built to provide a dry path from the cave’s entrance to a chamber across a lake within the cave.

Initially discovered in 2000, the bridge was first estimated to be 3,500 years old based on pottery analyses from a nearby cave chamber.

However, subsequent research, including radiocarbon dating of bones and pottery found on Mallorca, indicated possible human presence up to 9,000 years ago, though this was considered unreliable due to poor preservation.

More recent studies pointed to a settlement timeline of about 4,440 years ago.

The new insights gained by Professor Onac and his team came from studying historic sea levels and geological traces left by these changes.

“It was only in the past four years that we finally gathered the data needed to address this longstanding research topic and better estimate the arrival time of humans in Mallorca,” Onac noted.

As part of their analysis, the researchers examined a light-colored band and calcite encrustations on the submerged bridge, which formed during periods when sea levels were higher, inundating the cave.

These encrustations, known as speleothems, are formed from mineral deposits accumulating over time and were key in dating the bridge’s construction to about 6,000 years ago.

The level of the color band and the mineral deposits aligned with a period when the sea level was stable, indicating the bridge’s age at older than 5,600 years.

The use of the bridge and the cave itself is still under study, but scenarios include its use as a refuge, ritual site, or storage area, particularly to keep food cool during Mallorca’s hot days.

Cave divers have also found remains of the now-extinct Myotragus balearicus goat species and pottery in chambers accessible by the bridge, suggesting varied human activities.

Mallorca’s settlement history is peculiar when compared to other Mediterranean islands, which were settled earlier and had more favorable environmental conditions and abundant resources.

Onac speculates that despite its size and proximity to mainland Spain, Mallorca’s harsh climate and scarce resources made it less attractive to early settlers, in contrast to other islands that offered richer environments and resources.

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