The limestone caves and rock shelters of Indonesia’s southern Sulawesi island hold the oldest traces of human art and storytelling, dating back more than 40,000 years. Paintings adorn the walls of at least 300 sites in the karst hills of Maros-Pangkep, with more almost certainly waiting to be rediscovered. But archaeologists say humanity’s oldest art is crumbling before their very eyes.
“We have recorded rapid loss of hand-sized spall flakes from these ancient art panels over a single season (less than five months),” said archaeologist Rustan Lebe of Makassar’s culture heritage department.
The culprit is salt. As water flows through a limestone cave system, it carries minerals from the local bedrock, which eventually end up in the limestone. At the limestone’s surface, those minerals oxidize into a case-hardened rocky crust. Nearly all of oldest rock art in Maros-Pangkep—like the oldest drawing in the world that actually depicts an actual object—is painted in red or mulberry-purple pigment on that hard outer layer. It’s resistant to most weathering, providing a durable canvas for humanity’s oldest artwork.