ROCK ART MAY BE EARLIEST SIGN OF ARTISTIC BEHAVIOR.

Byline: John Noble Wilford The New York Times

Out in the remote tropics of northwestern Australia, where a 130-foot-high sandstone monolith rises starkly above the wooded plains, archeologists say they have found the rock face and many surrounding boulders engraved with thousands of circles, the work of people 75,000 years ago. It is by far the earliest known sign of artistic behavior, more than twice the age of any European cave painting and at least 15,000 years older than any previous Australian rock art.

Digging deeper at the base of the stone monolith, the archeologists made what may be an even more stunning discovery: red ocher and stone artifacts of an age that could triple the time people have occupied Australia, from about 60,000 years to 116,000 years and perhaps as much as 176,000 years.

These findings, if the dates are confirmed by further analysis, are expected to have a reverberating influence on the study of the origins of human creativity. Scholars have long identified cave and rock art as a defining characteristic of modern Homo sapiens, one of the cultural manifestations possibly reflecting the last transitions of the species to fully modern form.

But the new dates suggest that modern humans might not have been able to migrate to Australia early enough to be these artists. Could it be that in some rare cases, artistic expression began before modern Homo sapiens? Perhaps the first occupants of Australia were an archaic human species, though fully modern Homo sapiens appeared there later and nothing in the new findings, scientists said, changes the identification of today's aborigines as Homo sapiens.

One of the discoverers of the stone engravings, Richard Fullagar of the Australian Museum in Sydney, was quoted in today's issue of the Sydney Morning Herald as saying, ``It changes enormously the way we think about Australian prehistory.''

Alan Thorne, an anthropologist at the Australian National University in Canberra, said there was no reason why people could not have arrived on the island continent much earlier than previously thought.

But he and other specialists in human origins advised caution in drawing any conclusions yet as to whether, because of the evidence for much earlier occupation, the first Australians were fully modern or an archaic human species. One of the leading theories holds that modern Homo sapiens arose in Africa 100,000 to 150,000 years ago and then spread to the rest of the world.

``It's incredibly exciting,'' said Milford Wolpoff, a paleontologist at the University of Michigan who was familiar with much of the research.

A full scientific report on the research is to be published in the December issue of Antiquity, a British archeology journal, which made the paper available Friday. The Sydney Morning Herald published an extensive report on the exploration site, which is at a place the local aborigines call Jinmium. It is in the Northern Territory, near the border with the state of Western Australia and the town of Kununurra.

In explorations since 1987, Fullagar and colleagues recognized that the stone engraving at Jinmium were different from and probably older than the rock art, with colorful drawings of crocodiles, kangaroos and spirit figures, found scattered elsewhere through the northern tier of Australia. The strange circles, averaging 1.2 inches wide, were carved everywhere on the rock walls, even to depths of 5 feet buried in sediment. Each circle was described as being so perfectly formed that none varied in size or depth by more than a few millimeters.

In the Sydney Morning Herald article, Paul Tacon, an archeologist at the Australian Museum, called this ``a completely new form of art'' and said, ``I am 100 percent sure that there's no possible way these marks are not human in origin.''

Tacon compared the monolith and other huge stone blocks to Stonehenge in England. ``Here we have something comparable in that a cultural group sculpted large monoliths across an equally large area,'' he said.