Rock art becomes the prey of salt weathering.

In Sulawesi (Indonesia) we find some of the oldest petroglyphs. They are at least 44,000 years old and, in addition to supernatural beings, they perform hunting scenes. Petroglyphs are priceless. However, a team of Australian and Indonesian scientists has now come up with an alarming message: ancient petroglyphs are rapidly disappearing.

Weathering salts
It can be traced back to salt weathering, the researchers write in the journal Scientific news. Salt water penetrates the rock through cracks and holes and then evaporates. Salt crystals remain, which grow over time and increase cracks in the rock, which may eventually even disintegrate. “Our analysis shows that weathering of salts not only causes a chemically weaker rock surface,” says researcher Jillian Huntley. “The growth of salt crystals behind old rock art also ensures that chips fall from the walls;” rock art disappears before our eyes. “

Climate change
Because the rate at which rock art is disappearing is in line with the rate at which climate is changing, scientists believe that climate change is the driving force behind vanishing rock art. In Indonesia, periods of drought and heavy rainfall (monsoon rains) alternate. Scientists claim that such conditions promote rock rot. However, the flash weather that he now sees cannot be fully explained. This rock is currently deteriorating so rapidly that scientists are monitoring higher temperatures and more extreme weather conditions; both caused by climate change. “In my opinion, the degradation of this great rock art will worsen as global temperatures continue to rise,” Huntley said.

Researchers analyzed prehistoric art in eleven caves in the Maros-Pangkep cave complex in southern Sulawesi. “I was amazed to see how often devastating salt crystals were observed and their impact on rock works of art – some of which are more than 40,000 years old,” Huntley said.

Strongly influenced image of a boar. The painting is more than 45,000 years old. Image: Basran Burhan.

A race with time
It is a cause for concern. Because rock art gives us a unique insight into the (thinking) world of people who lived tens of thousands of years ago. It would be a shame if art was lost. In addition, we should not forget that not all works of art have been restored, emphasizes researcher Adhi Agus Oktaviana. “We have found more than 300 rock art sites in Maros-Pangkep.” Our team continues to search the area and look for new works of art every year. And almost all of them peel. It’s a race against time. ”

Scientists say it is very necessary to observe rock art. For example, it must be clear why some works of art disappear faster than others. In addition, it is important that measures are taken to protect rock art. Not only against the weather, but also against other threats such as mining.