Ancient Freshwater Reservoir Found Beneath Sicily’s Iblean Mountains
A global team of geologists has revealed a vast ancient freshwater reservoir tucked deep within Sicily’s Iblean Mountains. The underground pool is estimated to be around 6 million years old, and the researchers reported their findings in Contact Earth and Environment, a scientific journal.
During a review of maps from earlier expeditions that aimed to locate oil fields, the team instead uncovered compelling evidence of a major aquifer. The reserve holds about 17.5 cubic kilometers of freshwater, a volume comparable to the surface area of Lake Tanganyika, one of the world’s largest bodies of freshwater.
According to the study, the groundwater accumulated underground following the opening of the Strait of Gibraltar roughly 6 million years ago. The researchers propose that the flow was then blocked for about 700 thousand years, contributing to a partial drying of the Mediterranean basin. Over millennia, rainwater percolated down through the crust, seeping into porous rocks at shallow depths. When sea levels rose again, the confining pressure from seawater helped shut off the groundwater supply, effectively isolating the freshwater in its subterranean pocket.
The discovery aligns with similar findings in distant regions, including reports of a substantial freshwater lake located deep underground in New Zealand, which add to the growing picture of ancient, hidden aquifers around the world.
These insights contribute to our understanding of long term hydrological cycles and the resilience of freshwater resources. They also raise considerations for future water management in regions with limited surface reserves, as researchers continue to map subterranean pathways and the dynamics of ancient groundwater systems.
Credit for the discovery rests with the international team whose fieldwork and analyses illuminate how subterranean lakes can persist over millions of years, even when surface conditions shift dramatically. The work underscores the value of reexamining existing geological data with fresh eyes and advancing technologies to reveal hidden water stores beneath the Earth’s crust.