Last year, archeologist Mike Morwood and rock art specialist June Ross took the ride of their lifetime across the northwest Kimberley (Australia). They hired a helicopter and flew across largely trackless territory, their pilot landing periodically in spots where they believed a good rock art site might lie. The pair's aerial reconnoitre recorded 27 locations in which they documented a total of 54 rock art sites. "It was an absolute revelation," Ross recalls. "What struck us was how many rock art sites there are, and we developed a great admiration for the artists who made them."
     Across the Kimberley, hundreds of thousands of paintings lie in rock overhangs and caves, often behind curtains of tropical vines. But who were these prodigious artists, when did they come and what other traces did they leave of their presence? Such questions are among the most crucial in Australian archeology, according to Morwood and Ross. Like Arnhem Land in the Northern Territory, they say, the Kimberley may hold vital clues to understanding the origins of the first Australians. "In fact, given the proximity of island southeast Asia and the relatively short water crossing required at times of lowered sea level, the Kimberley was a likely beach-head for the initial peopling of Australia," Morwood says.
     In a bid to give substance to such speculation, Morwood, Ross and a team of multidisciplinary scientists will spend next month in the Kimberley, in the first of three expeditions to be conducted in successive years. Morwood's hope is that intensive study of selected sites will build up a picture of human occupancy and the sequence of rock painting styles, which "may prove one of the longest and most complex anywhere in the world". He says the area has a long history of human occupation, dating back 43,000 years or more.
     The geology of the Kimberley is a factor that acts in the researchers' favour. "In the Kimberley, the paint remains in the rock as a stain. And the rock surfaces are dense quartzite and sandstone, which are hard, very resistant to weathering and break down very, very slowly," Ross explains. "But out of the 54 sites we've seen, few have any significant deposits at all."
     To overcome this, Kira Westaway from Macquarie University will use cutting-edge rock art dating techniques. Using pollen samples, Australian National University scientist Simon Haberle will determine the vegetation that grew near the caves and the influence of climatic changes on its growth. Geographer Murray Scown will map ancient river systems, pinpointing permanent water sources that may have led humans to make their home there. Ross says: "We have to attack the problem with every possible tool. It's the direction that we have to go in archeology in Australia because we've got very few clues. Morwood thinks their research may turn up some of the earliest evidence for human presence in Australia, dating back 50,000 years. Ross is more cautious: "I don't want to predict what we'll find... But I think the Kimberley will be hugely important in answering significant questions [in] Australian archeology."

Source: The Australian (12 May 2010)