The Al Naslaa rock formation, found in Saudi Arabia, is one of Earth’s greatest mysteries.
Two boulders, six meters (20 feet) high, stand atop their own pedestals, separated by a perfectly smooth crack.
Possessing petroglyphs up to 4000 years old, Al Naslaa’s central fissure is iconic.
Although its cause remains debated, other terrestrial features hint at solutions.
In the United States, Balanced Rock displays similar “unstable equilibrium” features.
In sedimentary rock, different layers erode at different rates, commonly creating pedestal-like structures.
As the supporting material erodes, these ancient structures risk collapse.
Egypt’s White Desert contains similarly unstable features as well.
Combinations of wind, rain, sand, and flowing water all carve these structures over geological timescales.
Meanwhile, New Zealand’s “Split Apple Rock” shows a similar, almost-perfect split.
Planes of weakness in granite structures, known as joints, enable water-based weathering to cleave boulders apart.
The backside of Al Naslaa contains another cracked joint parallel to the main fissure: a potential clue.
All throughout the Arabian Peninsula, eroding sandstone and limestone lead to magnificent features.
Earthquakes and/or fault lines may have also played a role in creating Al Naslaa’s fissure.
Although its collapse is inevitable, Al Naslaa remains an enduring geological wonder.
Mostly Mute Monday tells a scientific story in images, visuals, and no more than 200 words. Talk less; smile more.