Desert Varnish and the Marine Transgression: A Chronological Indicator for Murujuga Rock Art
Ken Mulvaney [+]
University of Western Australia
A study of 1,358 petroglyphs recorded during the Dampier Archaeological Project (1980-1982) was conducted to identify patterns relating to the rock art and a mineral coating. This rock coating or desert varnish is present within a relatively small percentage of the rock art (20 percent), while many more petroglyphs truncate the varnish (34 percent). It was found that particular motif subjects are covered with the varnish, specifically those of macropod, elaborate non-figurative design, and certain types of anthropomorphic motifs; whereas marine subjects and different anthropomorphic forms cut through the varnish. Despite not being able to obtain an age determination for the varnish formation, or to estimate approximately when it may have formed, the subject dichotomy provides a strong correlation with the early phases of the rock art, at minimum, predating the formation of the Dampier Archipelago around 7,000 BP, with a later production period when a marine ecosystem became established.