Beringia and the Peopling of the Americas
Thursday, 14. February 2008, 15:28:29
Unfortunately there is not many earth science articles to be found on PLoS ONE http://www.plosone.org/home.action, the interactive open-access journal for the communication of all peer-reviewed scientific and medical research. On 13 January 2008 they published an anthropological paper that at least had a teeny bit of geological relevance, or maybe rather the other way round - it illustrates the importance of geology for the history of mankind.
In the paper titled A Three-Stage Colonization Model for the Peopling of the Americas there is of course a lot of genetic DNA-discussion, but here I shall keep to the geological and palaeoecological constraints on the timing.
My map is not very precise, and please don’t take the time too seriously (it is no better than something around 20,000 to 18,000 years ago), but I hope it can serve my purpose.
During the last Ice Age, when much of the northern hemisphere was covered with ice, the sea level was much lower than now. During the last glacial maximum sea level was lowered by ~125m. That is the opposite of the present situation with global warming. A landbridge connected America and Asia, where the Bering Strait now separates the two continents. The area called Beringia was a continuous landmass that connected Asia and North America for around 60 thousand years until around 11 or 10 thousand years ago. Because of its aridity, much of Beringia remained unglaciated during the ice ages, the snowfall was extremely light due to the southwesterly winds from the Pacific Ocean having lost their moisture over the fully glaciated Alaska Range. Fossils indicate productive, dry grassland ecosystems and demonstrates that large mammals roamed Beringia. In fact it was fit for human population. Immigration from East Central Asia may have taken place in the period from 43 to 36 thousand years ago. To the east they would however have been stopped by the barrier formed by the North American Ice Sheets. This isolation from continental North America lasted until at least 14 thousand years ago when an intracontinental ice-free corridor opened up between the Laurentide and Cordilleran Ice Sheets. Migration could by then also take place along the ice free Pacific coast.
After 11–10 thousand years ago sea levels rose sufficiently to re-inundate Beringia, creating the Bering strait that now separates Alaska from Siberia by at least 100 km of open frigid water.
* A Three-Stage Colonization Model for the Peopling of the Americas - http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001596
* Beringian Standstill and Spread of Native American Founders - http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000829
Other land bridges around the world have been created and re-flooded in the same way: approximately 14 thousand years ago, mainland Australia was linked both to New Guinea and to Tasmania, the British Isles were an extension of continental Europe via the English Channel, and the dry basin of the South China Sea linked Sumatra, Java and Borneo to the Asian mainland.
In the paper titled A Three-Stage Colonization Model for the Peopling of the Americas there is of course a lot of genetic DNA-discussion, but here I shall keep to the geological and palaeoecological constraints on the timing.
My map is not very precise, and please don’t take the time too seriously (it is no better than something around 20,000 to 18,000 years ago), but I hope it can serve my purpose.
During the last Ice Age, when much of the northern hemisphere was covered with ice, the sea level was much lower than now. During the last glacial maximum sea level was lowered by ~125m. That is the opposite of the present situation with global warming. A landbridge connected America and Asia, where the Bering Strait now separates the two continents. The area called Beringia was a continuous landmass that connected Asia and North America for around 60 thousand years until around 11 or 10 thousand years ago. Because of its aridity, much of Beringia remained unglaciated during the ice ages, the snowfall was extremely light due to the southwesterly winds from the Pacific Ocean having lost their moisture over the fully glaciated Alaska Range. Fossils indicate productive, dry grassland ecosystems and demonstrates that large mammals roamed Beringia. In fact it was fit for human population. Immigration from East Central Asia may have taken place in the period from 43 to 36 thousand years ago. To the east they would however have been stopped by the barrier formed by the North American Ice Sheets. This isolation from continental North America lasted until at least 14 thousand years ago when an intracontinental ice-free corridor opened up between the Laurentide and Cordilleran Ice Sheets. Migration could by then also take place along the ice free Pacific coast.
After 11–10 thousand years ago sea levels rose sufficiently to re-inundate Beringia, creating the Bering strait that now separates Alaska from Siberia by at least 100 km of open frigid water.
* A Three-Stage Colonization Model for the Peopling of the Americas - http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001596
* Beringian Standstill and Spread of Native American Founders - http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0000829
Other land bridges around the world have been created and re-flooded in the same way: approximately 14 thousand years ago, mainland Australia was linked both to New Guinea and to Tasmania, the British Isles were an extension of continental Europe via the English Channel, and the dry basin of the South China Sea linked Sumatra, Java and Borneo to the Asian mainland.
You must be logged in to write a comment. if you're not a registered member, please 
