By re-examining animal bones which were found in the Bluefish Caves in northern Yukon, Canadian researchers have discovered that the 36,000 bones were damaged by stone tools. The bones had been previously radiocarbon dated, about 30,000 years ago.
Radiocarbon dating, also called carbon-14 dating, is a standard tool used by researchers for determining the age of an object. It uses radiocarbon, which is a radioactive isotope of carbon. The carbon-14 takes 5,730 years for half of the isotope to decay. Scientists measure the remained content and then work backward to figure out when the animal died. Radiocarbon is all around in the air we breathe; when an animal stops breathing, the stores of oxygen in their body start to decay.
Since there were no other archaeological sites in the original area of the bones, it was decided to radiocarbon date them again to confirm the age of the find. The bones that they had were from mammoth, horse, bison, and caribou. They were stored in the Canadian Museum of History in Gastineau and had taken two years for the researchers to examine them. The oldest bone in the collection, a horse mandible, had stone marks on it and was dated as 23,000 or 24,000 years old. The examination has confirmed that the site is the earliest known human settlement in Canada.
Professor Ariane Burke, the scientist who is studying this collection, states that the mandible clearly shows that Eastern Beringia had human settlements during the last ice age. Studies have shown that in Beringia, the area between the Mackenzie River in Canada and the Lena River in Russia, lived about a thousand people, 15,000-24,000 years ago.
They lived in isolation since the presence of glaciers made the land around them inhospitable. This caused not only geographical isolation but genetic isolation as well– the inhabitants of the Bluefish Caves are the ancestors of the people who had colonized the continent from the coast to South America after the last Ice Age. No one is sure how they got to Beringia in the first place, as no evidence has been discovered yet, Mail Online reported.
In the last Ice Age, which is also called the Pleistocene Period, the continents moved to where they are today. At the coldest point in this time, ice sheets covered the entire Antarctica, vast areas of North and South America, Europe, and small parts of Asia. The ice would cycle through advancing and retreating, freezing and thawing– for at least 20 times. The Ice Age changed the land by eroding and depositing material. It altered the river systems, made new lakes, and changed the sea level.