Ancient stone tools chip away date of early humans' arrival
Scientists have long held that people did not arrive in the Americas until after the Ice Age.
Now a controversial archaeologist has unearthed signs of life in Alberta thousands of years before the glaciers.
BY MARGARET MUNRO
Dr. Jiri Chlachula,an archaeologist, was hiking along the Bow River near his Calgary apartment when he noticed a stone, the size of a fist, with revealing chips on its side. He knew it was not an ordinary stone.
He took it home to study, and is now convinced it and dozens of other flaked stones he has since unearthed in Alberta were shaped by human hands at least 20,000 years ago.
If he is right - and several senior scientists suspect he is - Dr. Chlachula has discovered the oldest human artifacts yet found in southern Canada. The stone tools could prove early humans roamed the Canadian Prairies long before the last Ice Age. The evidence was simply buried by the glaciers.
For decades, archaeologists have argued that the giant ice sheets that entombed Canada between about 12,000 and 21,000 years ago were an impenetrable barrier. The glaciers, which were hundreds of metres thick, would have delayed people's trek south until after the ice melted. While many researchers question the theory about the glacial barrier, no one, until Dr. Chlachula, had come up with an arti- fact to prove it wrong.
The brash archaeologist from the Czech Republic stumbled on his first artifact along the Bow River within weeks of arriving in Calgary to do a PhD in archaeology in 1990. He later concluded in several controversial research papers that the Calgary stone tools predate the Ice Age.
Recently, Dr. Chlachula and his colleagues have discovered three more sites containing what they believe are preglacial stone tools.
One set of choppers and scrapers, described in the current edition of The Canadian Journal of Earth Sciences, was found in a gravel pit near the town of Grimshaw in northern Alberta. The other tools were unearthed last summer at two locations west of Lethbridge.
One set of choppers and scrapers, described in the current edition of The Canadian Journal of Earth Sciences, was found in a gravel pit near the town of Grimshaw in northern Alberta. The other tools were unearthed last summer at two locations west of Lethbridge.
All of them, says Dr. Chlachula, indicate that humans roamed through the Prairies between 20,000 and 40,000 years ago.
His latest claims will create further controversy, but several respected scientists think he may be right, give or take a few thousand years.
Dr. Richard Morlan, curator of paleo-environmental studies at the Canadian Museum of Civilization in Hull, Que., says he has no reason to doubt Dr. Chlachula. Few people in the world, says Dr. Morlan, can match the 36-year- old researcher's expertise.
Professor Nat Rutter, the former head of geology at the University of Alberta in Edmonton, agrees, noting that Dr. Chlachula has three PhDs and extensive field experience in both old world and new world archaeology. (Dr. Chlachula had a PhD in archaeology when he arrived in Canada, earned another PhD in archae- ology at the University of Calgary then went to Edmonton to do a third PhD in geology.)
Professor Nat Rutter, the former head of geology at the University of Alberta in Edmonton, agrees, noting that Dr. Chlachula has three PhDs and extensive field experience in both old world and new world archaeology. (Dr. Chlachula had a PhD in archaeology when he arrived in Canada, earned another PhD in archae- ology at the University of Calgary then went to Edmonton to do a third PhD in geology.)
"If they're right, and I think they are, they've got a major find," Prof. Rutter says of the stone tools Dr. Chlachula and his colleague Louise Leslie have re- ported finding in the Grimshaw gravel pit.
They came across these artifacts while working at the University of Alberta. Ms. Leslie, a fellow graduate student, showed Dr. Chlachula some interesting rocks she had found near Grimshaw. After one look at the flaked rocks, he made plans to visit the gravel pit for a closer look.
He and Ms. Leslie soon uncovered more flaked tools, which they have concluded were made and discarded before the advance of the ice sheets, about 20,000 years ago. The tools were later covered up by several metres of glacial sand and gravel.
The scrapers and choppers that Dr. Chlachula found near Lethbridge last summer were also buried beneath more than 10 metres of glacial debris. The stone tools were visible because the so-called glacial till had been cut away by erosion. It will take more work to establish the details at the Lethbridge sites, but Dr. Chlachula is sure they are preglacial.
He and Ms. Leslie soon uncovered more flaked tools, which they have concluded were made and discarded before the advance of the ice sheets, about 20,000 years ago. The tools were later covered up by several metres of glacial sand and gravel.
The scrapers and choppers that Dr. Chlachula found near Lethbridge last summer were also buried beneath more than 10 metres of glacial debris. The stone tools were visible because the so-called glacial till had been cut away by erosion. It will take more work to establish the details at the Lethbridge sites, but Dr. Chlachula is sure they are preglacial.
Experts agree his findings could fill in some of the blanks in the history of the peopling of North America.
Early humans were living in Siberia at least 100,000 years ago and had made it across the land bridge into Alaska and the northern Yukon 25,000 years ago. It has also become clear that people were in the central United States and South America at least 12,500 years ago.
The big question is: How and when did they move south?
The most obvious routes would have been down the coast of Alaska and British Columbia on ancient lowlands that are now under water, and down through what is now the Canadian Prairies.
Dr. Chlachula, who is echoed by other archaeologists, believes "paleo-Canadians" lived on the grasslands and forests that existed on the Prairies during a warm spell 30,000 to 40,000 years ago. "Plenty of animals roamed the land and there's no reason to think people didn't," he says.
These nomadic people would have set up camps and left piles of animal bones at kill sites. They also would have created simple stone tools to scrape hides and smash bones, and likely discard- ed them as they moved along.
Such simple stone tools may be enough to convince Dr. Chlachula that people were on the prairies along with the mammoths and prehistoric bison and antelope. But he agrees it would be much easier to convince the skeptics if there was more clear-cut proof. "Like a dead hunter, with a spear in his hand and a dead mastodon lying beside him," he quips.
Given Canada's geological history, that is unlikely. The glaciers, which started growing and scraping across the Canadian landscape like bulldozers 25,000 years ago, would have obliterated most evidence of human activity.
But Dr. Chlachula believes a substantial and irrefutable col- lection of stones tools and other artifacts could be uncovered if people were more open to the possibilities and made a concerted effort to find them. He says there are probably plenty of stone artifacts under the massive heaps of gravel that the glaciers piled up in the Yukon, western Alberta and British Columbia be- fore they retreated.
Dr. Chlachula, whose collection of stone tools is stored at Alberta's provincial museum, recently returned to the Czech Republic to head the paleo-ecology lab at Technical University Brno. But he is keen to collaborate with scientists interested in hunting for early artifacts in Canada.
He says Canadian archaeologists have "just been scraping the surface" by looking for arti- facts close to the surface and need to search in or below glacial deposits. They also need to couple their work with a better understanding of rudimentary stone tools, he says. European archaeologists have long accepted such flaked stones as artifacts, since they have been found with human remains in eastern Eu- rope and Siberia dating back at least 100,000 years.
Dr. Alan Bryan, professor emeritus of archaeologist at the University of Alberta, says his young colleague makes a good point. "We archaeologists have got to train ourselves to be more observant and open to possibilities," says Prof. Bryan, who worked with Dr. Chlachula excavating the stone tools along the Bow River.
He originally shared Dr. Chlachula's opinion that those stone tools predated the last Ice Age. After a closer look at the glacial deposits the tools were found in, he has concluded they are prob- ably no more than 13,000 or 14,000 years old, and were likely dropped as the glaciers receded. While not as old as Dr. Chlachula believes, that would still make them the oldest human artifacts found in southern Canada.
Prof. Bryan has not examined the artifacts from the Lethbridge or Grimshaw sites. But he says the report on the Grimshaw find in The Canadian Journal of Earth Sciences "is very suggestive." The stone tools could be well over 20,000 years old, though he would like to see more proof.
But he does believes Dr. Chlachula is on the right track.
"His work will fit in ultimately to a real understanding of when people came to North America," Prof. Bryan says, adding that it "was a lot earlier than most archaeologists think.
"Twenty-five 30,000 years ago seems perfectly reasonable to me," he says, pointing to mounting evidence of early human activity in the United States and South America.
Human footprints, tools, and huts found at Monte Verde in southern Chile date back an esti- mated 12,500 years. The people who lived at the site, excavated over the past decade by a team from the Southern University of Chile, used more than 60 different kinds of medicinal and edible plants. They harvested such crops as potatoes and covered their huts with mastodon hides.
Human footprints, tools, and huts found at Monte Verde in southern Chile date back an esti- mated 12,500 years. The people who lived at the site, excavated over the past decade by a team from the Southern University of Chile, used more than 60 different kinds of medicinal and edible plants. They harvested such crops as potatoes and covered their huts with mastodon hides.
There is also tantalizing evidence of a much earlier human presence at Monte Verde. Rocks that may be stone tools date back 33,000 years.
Another site, where it appears hunters butchered a mammoth beside a lake 18,000 year ago, has recently been unearthed in Nebraska. Some scientists are skeptical, but Dr. Morlan, of the Canadian Museum of Civilization, has little doubt the leg bones of the mammoth were "broken with high-velocity impacts by people using a hammer stone." He is well versed on the finer points of mammoth bone breaking. He headed a team that unearthed mammoth bones in the northern Yukon.
Early people, he explains, used to suck marrow out of the bones. Then they would hit the animals' huge leg bones with stone tools to create bone flakes which they used as knives. "You can butcher a mammoth with its own bones."
Early people, he explains, used to suck marrow out of the bones. Then they would hit the animals' huge leg bones with stone tools to create bone flakes which they used as knives. "You can butcher a mammoth with its own bones."
The bones Dr. Morlan helped dig up at Old Crow flats, in the northern Yukon, are between 25,000 and 40,000 years old, making them the oldest artifacts found in Canada. But they are not in their original setting, which has made it hard to prove beyond doubt that the bones were touched and smashed - by people. "Though I've not found another way to account for the kind of fractures that we see there," he says.
At Bluefish Caves, about 65 kilometres south of Old Crow, a collection of stone tools and bones from several prehistoric animals, including mammoth, antelope, bison and large cats, is more convincing.
"We have definite evidence for people living at Bluefish Caves just after 25,000 years ago," says Dr. Morlan, who is intrigued by the stone tools Dr. Chlachula is finding in Alberta.
"We have definite evidence for people living at Bluefish Caves just after 25,000 years ago," says Dr. Morlan, who is intrigued by the stone tools Dr. Chlachula is finding in Alberta.
He has examined Dr. Chlachula's chipped rocks from the Bow River. "I certainly believe those are artifacts, yes, indeed, I don't have a problem with that," he says, adding he will leave it to the geologists to debate their age. Dr. Morlan has not examined the Grimshaw and Lethbridge finds, but is inclined to trust Dr. Chlachula's interpretation: "I simply assume he's identified the arti- facts correctly, and I certainly trust him to interpret the geology," he says.
Prof. Rutter, at the University of Edmonton, also has much confidence in his research skills.
"Jiri's work embarrassed a lot of other people," he says, because it suggests that Canadian archaeologists have been looking in the wrong place for human artifacts and they should be hunting underneath glacial deposits.
"They may not admit it," says Prof. Rutter, "but they're all out there looking now." National Post
"They may not admit it," says Prof. Rutter, "but they're all out there looking now." National Post
National Post, 16 January 1999, page B12.
