For decades, nobody could say how old the Blythe Intaglios really were. That changed when a study in the journal Arts put real numbers on these giant desert drawings near Blythe in the Colorado Desert of southeastern California, using a technique called rock varnish dating, specifically the cation-ratio (CR) method. The study's authors estimated that three of the site's human and animal figures are probably at least 1,000 years old.
A find no one was looking for
