The giant rock art murals that grace the walls of hundreds of shelters and caves found in the hills of the high sierra in Baja California Sur (Mexico) date back as far as 7,500 years ago, according to data from an ongoing study of the area. The ancient dates for the paintings cast little light on the mystery of who made them and why, but it suggests that whoever the painters were they came well before the Aztecs.
     "Once we did the dating and got to know how old they are, we were surprised by their antiquity because they look so fresh, so well preserved," said Alan Watchman, a geoscientist and Australian Research Fellow at the Australian National University in Canberra and co-leader of the study team. The paintings are of static giant humans and animals bound in herd-like movement, mostly done in red and black but also in white and yellow.
     The murals had previously never been dated and even today little is known about the people who created them or what they were meant to communicate. Watchman and his colleagues are conducting a multi-year project in the Sierra de Guadalupe to put the paintings in cultural context. Before the team started work, about 90 rock art sites were known in the region. Since then, the team has documented more than 320 additional sites. Now that preliminary dates for the paintings are established, the team is searching for a site they can excavate for other materials to substantiate the dates of the art and help tell the story of who the painters were.
     Harry Crosby, an author and Baja California rock art expert, said that until archaeologists are able to substantiate the rock art dates with other well-dated materials the mystery of the painters will remain. "A lot of these rock art sites have over-painting," said Crosby. "One figure is painted on top of another. In some places they have as many as five layers." To Crosby this suggests that many years must have passed between the first painting and the last. Watchman, who is a specialist in rock art dating, obtained his dates from painted samples collected in 2001. More than 30 samples have been dated so far and several of them are at least 5,000 years old. Some go back 7,500 years, suggesting a painting culture that lasted for millennia. Further studies in the years to come may resolve the mystery of who painted the murals, for what reasons, and how they vary through space and time.

Source: National Geographic News (17 July 2003)