Israeli researchers said Thursday they have surveyed what they now believe to be the world’s longest salt cave, a network of twisting passageways at the southern tip of the Dead Sea.
A recently completed survey of the Malham Cave determined the labyrinthine cavern stretches more than 6 miles in length. That puts it well ahead of Iran’s Namakdan Cave, previously thought to be the longest salt cave.
The survey was conducted by the Hebrew University of Jerusalem and a collection of Israeli, Bulgarian and international volunteers.
Boaz Langford, a researcher at the university’s Caves Research Center, and Antoniya Vlaykova, a Bulgarian cave explorer from the European Speleological Federation, headed the expedition.
“What’s unique about this cave, as opposed to other salt caves in the world, is that it’s the longest in the world,” Langford said, resting in a chamber of the cave.
Langford and Vlaykova said they plan to publish the complete map of the cave in a professional publication in the coming months.
There is no official record for the longest salt cave, and such designations are generally decided by consensus among cave researchers after an underground chamber is mapped and published.
Namakdan, which is about 4 miles in length, was identified as the longest salt cave after a study by Czech and Iranian scientists in 2006.
Salt caves are unusual and rare geological features. Because salt is highly water soluble, large salt deposits do not normally survive long on the surface. Only a handful of salt caves are larger than half a mile in length. Salt caves tend to only exist in highly arid regions, like the area around the Dead Sea, which is located at the lowest point on earth and is too salty to support animal life.
“The salt layers are squeezed out from the sub-surface, where they are deposited a few kilometers underground, and while being squeezed out they form a mountain, which is rising still today, at a rate of about one centimeter per year,” said Amos Frumkin, a Hebrew University geologist who has studied the cave for decades.
The Malham Cave’s main outlet yawns not far from a salt pillar named “Lot’s wife.” On the mountainside above, Langford, Vlaykova and their colleagues have identified at least 19 openings where seasonal floods have percolated through Mount Sodom’s rock salt to form the cave.
Yoav Negev, founder of the Israeli Cave Explorers Club, said that over two years, his group and a total of 80 volunteers from nine countries spent around 1,500 workdays measuring and mapping the cavern’s recesses.
“It’s above and beyond what we expected,” he said.
Efraim Cohen, one of the Hebrew University cave explorers, described the process of locating the cave’s entrances from the surface, rappelling down into surface shafts, squeezing through tight passages, and measuring each of the cavern’s serpentine branches with lasers.
Despite the difficult environment, he said the cave’s splendor makes it worth it.
“All the stalagmites and stalactites, their beauty, their color — they’re really white, they’re shining, they’re amazing,” Cohen said.