A study led by the University of South Florida has shed new light on the history of life in Mallorca, Spain.
An underwater bridge located inside Genovesa Cave, first discovered in 2000, has been dated back to nearly 6,000 years old, according to Dr. Bogdan Onac, a geology professor at the University of South Florida and leader of the study.
Previously, the bridge was estimated to be 3,500 years old, based on pottery found near its location. However, the new study, published in the journal Communications Earth & Environment, has revealed that the ancient limestone bridge is significantly older.
“By estimating the timeline of the bridge construction, our research suggests that humans likely arrived on Mallorca nearly 2,000 years earlier than previously thought,” Onac said. “This discovery significantly narrows the gap between the colonization timelines of islands in the eastern (started 13,000 years ago) and western Mediterranean.”
To reach this conclusion, researchers examined “mineral overgrowth on preexisting stalactites near the bridge” and “analyzed the elevation of a coloration band” found on its upper section.
Divers were sent about five meters below the water surface to collect mineral samples.
“Both indicators suggest that these features formed during a period of sea-level still [and] stand between 5,800 and 5,500 years ago. This implies that the bridge must have been constructed before this time frame, but not after 5,600 years ago, as the sea level would have already risen above the bridge by then,” Onac explained.
The submerged state of the stone bridge raises the question of its preservation.
Paradoxically, being underwater has actually aided in preserving the stone bridge. If it had been above water, it would have been exposed to various elements that could have damaged it.
“The submersion of the stone bridge actually helped preserve it,” Onac said.
“Constructed from large limestone blocks, likely sourced from cave breakdowns, the flooding served as a protective measure. Had the bridge been exposed, especially with the impact of mass erosion, its fate could have been quite different,” Onac continued. “Fortunately, water does not damage limestone, so the bridge remains well-preserved in its submerged state.”