IN SEARCH OF THE FIRST AMERICANS : ABOVE THE ARCTIC CIRCLE IN ALASKA, SCIENTISTS COMB A DESOLATE MESA FOR CLUES THAT WILL DATE THE ARRIVAL OF NORTH AMERICA’S EARLIEST IMMIGRANTS

The hunter pulled the animal skins tight as the Arctic wind howled across the mesa. It was the season when the sun never sets, but the icy gusts slashed his skin. His numb fingers held a stone he had found along a riverbank, and he chipped an edge on it, rock against rock, the flakes falling into the flames of a fire pit he had dug in the sandy soil.

Keeping their weapons close, his companions hunkered around the willow and birch branch fire. From the top of the mesa, 200 feet above the tundra, they waited for the great bison to come their way again, to help them feed the three or four families camped along the river below. They were hunters; they were hunted. Saber-toothed cats prowled the banks of several rivers that twisted through the gentle slopes north of the great range of mountains where they camped.

To the south, glaciers the size of small continents covered the land. To the north lay a frozen ocean. The hunters had come out of the west, across a broad plain that was slowly sinking beneath a rising sea. Within a few hundred years, the waters would bury the land bridge that linked them to their past.

They had used the mesa lookout, with a nearby abundance of clear water and firewood, for several seasons. But each day the sun arced a little lower over the horizon, the air grew colder and they knew they must soon move on.

Over time, wind covered the hunters’ fire pits with dust, and the flowers that paint the tundra in subtle colors each spring knitted their roots, binding the soil into a protective cover, entombing the hearths for thousands of years. Slowly, Iteriak Creek washed away their encampments at the base of the mesa, erasing clues to mysteries that, more than 10 millennia later, would resonate powerfully in a nation of immigrants.

The ancient hunters’ curiosity about their environment, about those who had ventured into the unknown before them, was immediate, linked to survival. Why modern seekers are compelled to probe these hunters’ legacy is less clear. Yet suddenly, hopeful scientists from several fields swarm over this remote hilltop, driven, as if by instinct, to search for answers to questions that have long perplexed them: Who were the first inhabitants of the North American continent? Where did they come from? When? What were they like?

*

MIKE KUNZ POURS HIMSELF A CUP OF COFFEE, HIS FAIR SKIN ODDLY amber in the midnight sunlight filtering through the canvas mess tent that he and a fellow archeologist erected a few days earlier. More than a dozen smaller, yellow, green and beige dome tents spread across the tundra, at the foot of this remote mesa 150 miles above the Arctic Circle in Alaska, and the area bustles with more human activity than it has seen in at least 10,000 years.

Poking up from the north slope of Alaska’s Brooks Range, the Mesa--as this plateau is now known--is about 100 miles from civilization, a small Eskimo village. Kunz has a satellite telephone, and a helicopter to transport him and a half-dozen visiting scientists. Technology aside, he has laid down one rule ancient inhabitants of the grizzly-populated area might understand: No one leaves camp without a 12-gauge shotgun.

Kunz is 51, his hair is thinning and his beard has grayed. But he sounds like a kid when he talks of his discovery--of this Mesa that has become the magnetic pole for scientists intrigued with the conundrum of how the Americas were first inhabited.

Kunz came to Alaska in the ‘70s, when the only job open in archeology was chief environmental monitor for the millions of acres of pristine wilderness controlled by the U.S. Bureau of Land Management during that decade’s oil boom. Exploratory drilling was under way throughout much of the northern foothills of the Brooks Range, a barren chain of mountains more than 500 miles north of Anchorage, with jagged peaks and twisting rivers fed by the heavy snowfalls of the long winter night. Federal law requires that archeological surveys be conducted before wells can be drilled. That requirement, and the funding for surveys, was a dream come true for archeologists itching to explore the area for clues to how the Americas were first inhabited. They knew that an ice age ending about 10,000 years ago had lowered sea levels to the point that a coastal plain connected Siberia and North America. The plain has misleadingly been named the Bering Land Bridge, but it was more than 1,000 miles wide, a home to migratory game that apparently lured humans across from Siberia and into a new world. Yet archeologists were bedeviled. The sites that had been found in Alaska bore artifacts that were quite different from those found at the oldest archeological digs in the United States’ heartland. If the first Americans came this way, why didn’t the Alaskan artifacts better resemble those found farther south?

That puzzled Kunz, an expert on the stone tools used by the earliest Americans, the so-called Paleo-Indians. A few projectile points similar to spear points discovered in the Southwest had been found at various sites in the Arctic, but because they were not embedded in organic material that could be carbon-dated, it was impossible to determine how old they were. They could have been dropped there 10,000 years ago or yesterday.

In the summer of 1978, Kunz led an archeological expedition near a desolate area known as Ivotuk. “There is absolutely no substitute for walking the country,” he says, brushing aside a swarm of mosquitoes, near the present tent camp. “We would be out there all day long. We would just walk, from place to place. That way you see everything. You become intimately familiar with the landscape.”

Kunz and a colleague, Dale Slaughter, had walked all day, concentrating on hilltops where early hunters would most likely have made their camps, but they had found nothing of significance. Then they came across an unusual land form. Unlike the gently rounded hills that extended as far as the eye could see, the eroded mesa rose abruptly from the terrain, towering over the creeks like a natural cathedral. Strikingly similar to the buttes of the southwestern United States, it looked as if a small chunk of Arizona had been ripped from the desert floor and dropped here.

“We had come to this place, which we had seen from a long ways away. We got to the bottom and we hadn’t found much. We were both very tired. I told Dale, ‘I’m gonna climb up there,’ and he says, ‘I’m not climbing up that damn thing.’ ” It’s a decision that Kunz has never let Slaughter forget.

“I went up, and right away I saw there were (stone) flakes on the surface,” Kunz says. “They are the result of tool manufacturing. So I knew there was a site there. I’m walking along and all of a sudden, bingo, there’s a projectile point. I picked it up and I thought, ‘That looks kind of like Paleo-Indian stuff.’ I had worked with Paleo-Indian stuff almost my entire time in the Southwest, but when I came to Alaska in 1970, I figured I had seen the last of it.”

After all, Kunz says, the general assumption was that Siberians had drizzled across the land bridge and moved south over a period of perhaps 1,000 years, evolving and developing their spearhead-making as they went. “By the time they got down to the heartland, they are Paleo-Indians, not Siberians anymore,” he says. At least that’s what most archeologists thought then.

At first, he told himself that this discovery was just another case of finding a spear point that looked Paleo-Indian, but probably meant nothing. To be significant, the point would have to be datable, which is rarely possible because the Arctic soil is so thin and subject to such erosion that materials containing organic substances such as grass or wood are seldom found with the artifacts. But within an hour, he had found five more points. “This has got to mean something,” he thought.

Now a full-time archeologist with the bureau, Kunz returned to the site a year later, and carried out the first excavations. He found three hearths where hunters had camped while fashioning their weapons, and 11 projectile points buried in the charcoal left by the fire.

Living substances, such as shrubs or trees, produce carbon-14, which decays into nitrogen at a uniform rate the instant they die. Hence the charcoal could be dated using carbon-14 techniques. But in 1979, the process took so much material that the hearths had to be combined for the test. The laboratory dated the charcoal at 7,620 years. That was interesting, Kunz says, but puzzling because it indicated that the campfire was too recent to have been used by the earliest Americans.

Most researchers agree that migration began as hunters from Asia moved across the land bridge and into North America because that is the only known route that could have allowed humans in significant numbers to enter this continent. Some believe that the migration took thousands of years, beginning as long ago as 50,000 years and ending with the submersion of the land bridge about 10,000 years ago.

This early-migration argument is supported by archeological sites in Pennsylvania and South America that, by some estimates, range in age from as old as 15,000 years in Pennsylvania to 40,000 years in Brazil. But many archeologists question those early dates. The data that has surfaced is open to wide interpretation, they say, arguing that the oldest believable date for human occupation of the Americas is the famed Clovis site, in New Mexico, where projectile points were found amid mammoth bones dated about 11,500 years old.

Kunz and Richard Reanier, who was studying archeology at the University of Washington, did more digging in 1980 but found little. With excavations in this region so costly and physically demanding, only the most compelling clues are worth pursuing. “We drifted away from it,” Kunz says.

In the meantime, a new carbon-dating technique called accelerator mass spectrometry had emerged that used particle accelerators to determine more accurate dates with a much smaller sample. Although still a tricky process that occasionally yields faulty results, it has become one of the most important archeological tools. Particle accelerators count the amount of carbon-14, and the ratio between carbon and nitrogen tells precisely when the organic material was alive. The improved dating technique produced an astonishing figure. The carbon in one of the hearths had come from a fire 9,700 years ago.

In the past few years, additional hearths have yielded even older dates, and last year, the two archeologists hit the jackpot at the Mesa. One of the hearths was dated at nearly 11,700 years, indicating that it was older than the oldest sites discovered in the Southwest and the Great Plains. It was also the most productive hearth found, yielding 2,000 to 3,000 weapon-makers’ waste flakes and at least six projectile points. Some of the points had the distinctive fractures caused when rock is exposed to heat. “It can’t get any better than that,” Kunz says. “We got stuff right in the charcoal itself, and it got thrown in there when the fire was burning.”

Since the late ‘80s, discoveries near Fairbanks and at a group of sites called the Nenana Complex north of Denali National Park have produced artifacts similar to those found in the southwestern United States. “All of a sudden, whoa, we’ve got full-blown, recognizable Paleo-Indian stuff in Alaska between 10,000 and 12,000 years ago,” Kunz says. “That’s just a totally new concept.”

Siberian-like artifacts have been found elsewhere in Alaska, but extensive archeological research in Siberia has failed to turn up any artifacts similar to those found at the Mesa. That could mean the Mesa hunters did not originate in Siberia, as had been thought. Kunz, however, suggests that the small band of families came from elsewhere in Asia, supporting the increasingly popular theory that the first Americans crossed the land bridge in cultural waves as the weather permitted. If so, North America, even then, was a melting pot.

*

WITH TEMPERATURES DROPPING AND MOSQUITOES ON THE PROWL, THE mess tent is a canvas sanctuary at the end of each Mesa workday. One by one, scientists whip aside the tarp and step in to relax, thaw and talk science. George C. Frison stomps in, settles his large frame into a folding chair and braces for intellectual battle.

Frison spent the first half of his life as a Wyoming rancher and hunting guide before turning to archeology. Now a master of his field, he still looks and sounds like a man who would be at home herding a few thousand head of cattle, but when he talks of the first Americans, the scholar in him takes over. He is one of several independent experts invited by the Bureau of Land Management to evaluate what Kunz has found, and he is impressed.

But there is precious little he can conclude. “You’re dealing with a profession, if you want to call it that, in which no two people are going to look at the same database and arrive at the same conclusion,” Frison says. “It makes for a lot of enmity.”

Frison is a hunter himself, and so has certain instincts that are in short supply among archeologists. In some of his excavations in the Wyoming foothills, Frison has found spear points embedded in the bones of bison, removing any doubt about what they were used for. Although no animal bones have been found here, he feels comfortable concluding that the people who occupied the Mesa so long ago had hunting techniques similar to those he knows so well in Wyoming. “These were hunters,” he says matter of factly, “and these were points made for large animals.” And that, he adds, is about all he can confidently say about the Mesa people.

Other scientists, however, cite the football-field-sized Mesa excavation and other Alaskan sites discovered in recent years as evidence that could end one of the most vitriolic debates among early-American experts: When did the first Americans arrive here?

Some researchers are now pointing to these discoveries as evidence that the migration across the land bridge began as recently as 12,000--not 50,000--years ago. If that is the case, the first Americans were truly on the fast track, moving into the heartland of North America within a few generations.

A report published last January in the journal Science supports that theory. The authors, John F. Hoffecker, of the Argonne National Laboratory in Illinois, and W. Roger Powers and Ted Goebel, of the University of Alaska, Fairbanks, discovered Paleo-Indian artifacts at several 11,000-year-old sites just north of Denali National Park. Their article sides with archeologists who “have steadfastly maintained that compelling evidence for sites older than 11,500 years has yet to be found.”

That absence of reliably dated older sites indicates that there were no humans in North America before about 12,000 years ago, they contend. But others claim that the sites are probably there, buried beneath the seas that swept across the land bridge at the end of the last ice age. And a few contest even that, arguing that the earliest immigrants might have come by boat, and not necessarily from Asia.

“It drives you wild,” Frison says. “But that’s what makes it interesting.”

*

HOMO SAPIENS WAS AN OLD SPECIES BY THE TIME THE FIRST HUMANS MIgrated to North America. Homo erectus, a precursor to Homo sapiens, made his first appearance at least half a million years ago in Africa, Europe and China. In the 1920s, a Canadian professor discovered a human tooth in a cave in China. Later research determined that humans had warmed themselves by fire in the cave some 400,000 years ago. Those early humans eventually migrated up into Siberia, but no one knows exactly when.

As the sea level dropped during intermittent ice ages, humans could have crossed the land bridge into North America. Biologists have determined that large numbers of other animals did cross the bridge at various times during the last 80,000 years. The mere availability of the bridge has led some experts to argue that the first Americans might have come across more than 20,000 years ago. Still, the fact that there is no hard evidence of human occupation before 12,000 years ago is compelling enough for many to assume that the first Americans were very late arrivals.

That puzzles C. Vance Haynes, professor of anthropology at the University of Arizona and one of the world’s experts on carbon-dating. Like Frison, Haynes has journeyed to the Mesa, and the two sit side by side in the mess tent as others huddle around them.

“The land bridge was passable by animals that would attract people 22,000years ago,” Haynes says as he peers out from beneath the broad brim of a safari hat. “So why aren’t there a lot more (older sites)? That’s a good question.

“It’s obviously a significant site,” he says, motioning toward the imposing hill. “It’s clearly Paleo-Indian, and Paleo-Indian sites in this part of the world are rare.” But he is troubled by the wide range of dates suggesting that those early hunters were present for 2,000 years.

Haynes, who knows how carbon-dating can trick even the experts, estimates that the Mesa is probably only about 10,000 years old, meaning the hunters who came through here could have been among the last to cross the land bridge before the rising seas once again swallowed it. Or, he surmises with a devilish twinkle in his eye, perhaps they did not come across the bridge at all, but had returned from the south in pursuit of big game, and thus had learned their toolmaking skills somewhere else, in the hills of Wyoming, perhaps.

*

THE THREE-WEEK, SUMMER excavation is winding down on the Mesa, and in a few days, Haynes and Frison will head back to the routine academic life in Wyoming and Arizona. On this cold afternoon, though, the researchers again find refuge in the mess tent. The mosquitoes remain outside, but I am there, asking the same annoying questions that others have asked. What were these Mesa people like? How did they survive? Why had they come this way and how did they get across the glaciers to the south and into the heartland of what is now the United States?

The two draw upon a century of experience in attempting to answer. Most likely, they speculate, it was a band of just three or four families, led by a shaman, a charismatic leader who was “a better talker than somebody else,” Frison says.

“He had a gift for gab,” Haynes adds.

The shaman may have chosen the campsite but he probably was not a chief in the popular sense of the word, holding only loose authority over his followers. Those who sat on top of the Mesa and made the tools so critical to their survival probably had not much more status than those who had mastered the art of stitching together animal hides to protect them from the cold.

But their social structure was not as simple as it might seem, Frison adds. “There’s other bands around too, and they have very strict rules about marrying across lines. They don’t marry anybody within their own band, or unit. They are going to have strict rules as to who they will form a union with in another band, and they will have certain ritual ceremonies that they will carry out.

“If I’m up here hunting, and I want something to eat and I see an animal, I’m going to utilize every skill there is. But when they killed an animal, the spirit of that animal had to be properly treated. The belief was that if you didn’t properly treat the spirit of that animal, then they would no longer make themselves available to the human population. It was a symbiotic relationship between man and animals, and this had to be maintained ritually. Very carefully.”

And edible meat was only one of the resources they sought. “If you have people entering a new area and they find a flint source, that’s like gold,” Haynes says. “Now they’ve got an economic base and they can make tools.”

Tools are what drew Phillip Shelley to the Mesa. Looking like a malnourished Marlboro man, he kneels down amid the rocks along Iteriak Creek and picks up a cloudy, glass-like rock. He uses a chunk of limestone to chip away at the chert, and seconds later it crumbles in his hand.

“Damn,” he mutters.

Like other experts on tools used by the first Americans, the Eastern New Mexico University professor is a consummate flint worker. He has learned how to make tools himself so as to understand how the old masters did it. Normally, Shelley can take a piece of obsidian or chert and in a matter of minutes chip out a museum-quality projectile point. But he is having little luck today. The chert along the riverbank is so fractured that it breaks along hidden lines of weakness, rather than uniformly as it would if it were as homogenous as that found in the heartland. As he works at duplicating the spear points found atop the hill, his admiration for the early flint workers grows.

The spear points found at the site are all so similar, he says, that they do not represent the work of many craftsmen. “I don’t think there were more than one or two people making these things,” he says, swearing as another stone crumbles in his hand. If the site had been used for 2,000 years, he adds, many toolmakers would have worked there and some evolution in the technology undoubtedly would have taken place. Instead, he suspects that the site was probably used only for a few seasons.

Scientists can only guess what happened to these families. It is possible that they vanished in a disaster or simply died out. If, however, they followed the course that most scientists say the earliest Americans are likely to have traveled, they eventually moved east, into a broad valley between the great sheets of ice that blanketed eastern and western North America. From there, they followed the MacKenzie River between the ice fields into the heart of the continent.

Their numbers grew as they rapidly expanded across North America and pushed on into Central and South America, where they flourished for thousands of years until European explorers arrived to commandeer the land that had been claimed by the greatest migration in human history.

Now, with a less-ambitious relocation impending, Mike Kunz stands on top of the Mesa, looking at the shallow excavations and the tools and flakes they’ve produced. Only 3% of the site has been excavated, so he will return again next year and maybe one or two years after that to dig and sift and search.

Then Kunz will return to the bureaucratic grind in Fairbanks. And work at the Mesa will stop to await a new generation of archeologists, who will come armed with better tools and information.

Now, though, Kunz surveys his find like a victorious explorer, immensely proud of a discovery that adds, ever so slightly, to our understanding of those who came this way before.

“I’ve looked at lots of hills--hundreds, maybe thousands--and this is the only site I’ve found,” he says. “I love these accidental things. No amount of planning will ever replace dumb luck.”

A helicopter sounds in the distance. A crew will soon begin dismantling the camp as work draws to a close. The Mesa will again slip from humanity’s nagging scrutiny, back to the slumber that enveloped it for at least 10,000 years.