Cave experts at Saudi Geological Survey first learned of this lava tube from an Arabic newspaper which carried a story with the tabloid-like title “Man Lost in Cave for Three Weeks,” adding that the unwilling spelunker eventually exited the cave seventeen kilometers from where he entered. A team of speleologists (including the author of this article) went to have a look.
It took two days to find the cave, which turned out to be a lava tube, a kind of tunnel created when hot lava flows out from under a hardening lava crust.
A Lava Tube Near Jeddah
The entrance to Hibashi Cave is a hole 14 meters in diameter, located 300 kilometers east of Jeddah. A long slope leads down to a huge room where the exploration team decided to camp. This was not exactly an ideal campsite because they found the floor covered with a thick carpet of sheep and goat droppings. However, it was far better than enduring the icy winds howling on the surface.
Choking Dust and Sticky Stalactites
Inside, they entered a curious passage whose floor was covered with over a meter of extremely fine silt with a particle size of only ten microns. Later analysis showed this silt had been laid down some 6000 years earlier.
Every step the explorers took in this passage raised clouds of choking dust. As they made their way deeper into the cave, they found shallow “nest” depressions made by hyenas, wolves and foxes, which had formerly lived here. On the ceiling they found a most unusual kind of stalactite, which was soft, yellow and organic. Lab studies proved these were composed of bat urine and the explorers nicknamed them “stickytites.”
A Bat-Guano Fire
A hundred meters from the entrance, they came upon something even more curious: animal bones lying on a carpet of ash which continued on for nearly a thousand square meters. The bones looked normal from the top, but were charred and black underneath.
In time they learned that the bones had been carried into the cave by hyenas and wolves and that the ashes were all that remained of a thick bed of bat guano which had somehow caught fire and burned long ago.
Rare Cave Minerals
Samples of bones and rocks lying on the ash bed were sent to Prof. Paolo Forti, co-author of Cave Minerals of the World (NSS, 1997). Forti identified 19 significant minerals in the samples, including rare ones like arcanite, arnhemite, pyrocoproite and whitlockite. The great heat from the guano combustion had melted the “stickytites” and forced the generation of extremely rare organic compounds.
Eventually, Hibashi Cave was placed in the list of the world’s “top ten volcanic caves” for hosted minerals (Ghar Al Hibashi, Acta Carsologica, Ljubljana, 2004).
Mini Robots in Martian Lava Tubes
A few years later (November 2004), researchers at the New Mexico Institute of Mining and Technology realized that Hibashi Cave, with its extensive bed of fine dust, presents a perfect analog for the Lava Tubes of Mars.
Martian caves probably have a similar flat, silt floor due to the huge dust storms which are common on the Red Planet. A detailed map of Hibashi Cave (Saudi Geological Survey, 2005) has proven invaluable for simulating the microrobotic exploration of these far-away lava tubes.
Although Hibashi Cave turned out to be 581 meters long instead of 17 kilometers, the truth about the cave has proven to be more amazing than anything the tabloids could have dreamed up.
Source: Ghar Al Hibashi, Harrat Nawasif/Al Buqum, Kingdom of Saudi Arabia by John J. Pint et al. (Saudi Geological Survey, Jeddah, 2005)
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