GHAR AL HIBASHI, HARRAT NAWASIF/AL BUQUM,
KINGDOM OF SAUDI ARABIA
JOHN J. PINT, MAHMOUD A. AL-SHANTI ABDULRAHMAN J. AL-JUAID,
SAEED A. AL-AMOUDI, AND PAOLO FORTI
With the collaboration of
RAMI AKBAR, PETER VINCENT, STEPHAN KEMPE, PENELOPE BOSTON, FAYEK H. KATTAN,
ERMANNO GALLI, ANTONIO ROSSI, AND SUSANA PINT
Ghar al Hibashi (sometimes spelled Hebashi) is a lava cave situated near the center of Harrat Nawasif/
Al Buqum, a field of vesicular basaltic lava flows located east of Makkah in the Kingdom of Saudi
Arabia. The cave lies approximately 6-7 m below the surface and contains 581 m of mainly rectilinear
passages. Apart from lava stalactites, stalagmites and columns, Hibashi Cave contains many bones and
the desiccated scat of hyenas, wolves, foxes, bats, birds and domestic animals, most of which has been
well preserved due to the cave’s temperature of 20-21°C and humidity of 48 percent. A human skull
425 years old and a man-made wall were found in the cave, but no archeological studies have been
carried out. It is estimated that the cave may be 1.1 million years old.
Two large bat guano deposits in this cave caught fire at some point in the past, heating and
partially burning animal bones and rocks lying on the guano surface and possibly affecting "biostalactites"
thought to be formed of bat urine. These soft, yellowish, accretions, 4 cm or less in length
and up to 1 cm in width, are found throughout the cave.
A few samples of secondary chemical deposits were collected mainly from the burnt guano
areas for mineralogical analysis. Despite the scarcity of these samples, at least 19 different minerals
were detected, most of which are related to the biogenic mineralization of bones and guano deposits.
Three of them, pyrocoproite, pyrophosphite and arnhemite are extremely rare organic compounds
strictly related to the guano combustion, which have been observed until now only in a few caves in
Africa. Ghar al Hibashi may now be considered one of the richest known mineralogical shelters of the
Arabian Peninsula, for which reason it has been included in the list of the ten minerologically most
important lava caves in the world.
The original floor of Hibashi Cave is covered with a layer of fine (10 micron particle size) silt
or loess, dominated by quartz, feldspar and kaolin, extending to almost every point in the cave. This
silt is up to 1.5 m deep and was OSL-dated at 5.8±0.5 ka BP at its lowest level. Because similarly
fine material is often blown about on the surface of Mars, researchers planning for the exploration
of Martian lava tubes are using photographs and maps of Hibashi Cave to produce robotic motion
simulations for testing the capabilities of microrobotic designs to navigate inside the caves of Mars.
The potential also exists to study phytoliths, found inside plant material preserved in animal
scat abundantly available in Ghar al Hibashi, in order to learn more about past flora of the Arabian
Peninsula as well as the process of desertification.