For nearly a century, skeptics dismissed a Paleolithic cave painting as merely rust-red iron oxides, the kind of natural staining one might see from mineral runoff on cave walls practically anywhere in the world. The painting’s almost modernist aesthetic didn’t help either: a column of parallel lines beside speckled splotches of red like a Jackson Pollock original. But new research, including radioactive isotope dating and advanced image processing, has now confirmed that these unusual markings found inside a south Wales cave in 1912 really are ancient abstract art. Study coauthor George Nash, an archaeologist who specializes in prehistoric paintings, said he surprised himself with his team’s ability to correct the record on this wrongfully discredited find, vindicating the turn-of-the-century British and French anthropologists who first made this discovery.…