The Calico Early Man site, located east of Barstow, California, has been an archaeological site of some distinction ever since Louis Leakey visited it in 1964 shortly after its discovery. Although no human remains such as bone or teeth have been unearthed as yet, over 60,000 tools and flakes have been collected. Most of these are kept in the San Bernardino County Museum under the watchful eye of Ruth Simpson, Museum Director and archaeologist. There exists a debate over whether the artifacts were made naturally or by the hand of man. Many experts in the scientific community are now convinced of the authenticity of the site.
The latest dating of the alluvial deposit where the implements reside has been set at 135,000 years old! This establishes the approximate geological date of the artifact-bearing level. You might say, "Sure, the geologic level may be that old but how do you know when the tools were actually made?" Good question! In 1981 scientists Ku and Bischoff used the uranium-thorium method to yield a date of 200,000 years (+/- 20,000) for the artifacts at the bottom of the geologic level in question. The topmost soil layer was estimated at 100,000 years. Therefore, the artifacts which were made and then covered over by later deposits have to be older than the youngest layer above them. Fred Budinger, assistant director of the site, says that this "new date is scientifically important because it provides a second independent age assessment of these beds."
This date is unusual because it is believed that the first people arrived in North America during the last ice-age, approximately 20,000 - 30,000 years ago, crossing the land-bridge at the Bering Sound, from northeastern Siberia into Alaska. The oldest documented human cultures in North America are Sandia (15000 BC), Clovis (12000 BC) and Folsom (8000 BC).
WASHINGTON (AP) Primitive humans thrived in the harsh, cold climate of northern Siberia 300,000 years ago, eons earlier than once believed possible, as indicated by the dating of stone tools found in frozen tundra.
The finding means that primitive humans were clever enough to live in one of the most severe climates on Earth far earlier than most experts had thought possible, said Michael Waters of Texas A&M University, the head of a field expedition to Siberia.
"Prior to this, the oldest known occupants of Siberia were about 30,000 years ago," said Waters. "Before this, it was thought that only (anatomically) modern humans could have lived there."
He added, "It shows us that people even in that early time had the skills to deal with the severe cold."
The study, to be published Friday in the journal Science, adds to a growing body of evidence that primitive humans were more intelligent, organized and resourceful than previously believed. Other scientists reported this week the discovery in Germany of some 400,000-year-old spears and evidence of a skilled hunting culture.
Waters said these findings are a surprise because most researchers had thought sophisticated survival skills came into wide use among ancient humanlike animals only with the appearance about 150,000 years ago of anatomically modern humans.
The Siberian site studied by Waters and his team is called Diring Yuriakh. It is located on a plateau above the Lena River, near the town of Yakutsk about 480 km south of the Arctic Circle.
Russian archaeologists first excavated the site in 1982 and discovered that it was an ancient quarry that had been used during several different periods of human occupation over many thousands of years.
Waters and colleagues from the University of Illinois were invited to determine the age of the oldest site using a technique that counts the number of electrons trapped in the grains of quartzite sand.
The Americans took a number of samples, said Waters, and determined that the crude stone tools were between sediment layers 260,000 to 370,000 years old.
Waters said the weather in Siberia 300,000 years ago is thought to have been very much like the present-day weather. Winter temperatures at Diring Yuriakh routinely drop to minus 50, and the soil freezes down to about 1 meter.
No bones, animal or human, have been found in Diring Yuriakh, and Waters said it is uncertain how long the ancient humans lived there. Their primary food source also is unknown, he said, although the nearby Lena River probably had fish, and large animals, such as elephant-like mammoths, lived in the area.
"We know very little about these humans," said Waters. He said it is not known which of the premodern human species could have lived at the Siberian site 300,000 years ago.
Some scientists have said the crude stone tools found at Diring Yuriakh were actually made by natural processes, not by human hand. But archaeologist Rob Bonnichsen of Oregon State University said he believes the site analyzed by the Waters team clearly was once a home to an ancient people.
"It is obvious that this is a human site," said Bonnichsen. The fist-size stone tools recovered from the site are thought to be quartz stones that were shaped by pounding them against other stones until a sharp edge was developed. The process left markings that could not be made by natural forces, said Waters.
But the ultimate proof came when scientists found a debris pile at what may have been a toolmaker's work station. In the debris pile were distinctive quartz flakes. Some of the flakes could be fitted exactly into the sharpened faces of some of the stone tools, said Waters.