TERRAFORMING TERRA
We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.
Saturday, August 27, 2016
First Humans Entered the Americas Along the Coast, Not Through the Ice
Of course they did! I said as much a decade ago when there was zero support for this alternative. Dogma then opposed the idea that ancient man were skilled mariners when the evidence was already exceptionable. Actual capability existed a full twenty thousand years ago.
What that means is that we have human remains and that their implied musculature for the upper body conforms to that of a skilled sea kayaker.
The passage along the coast was still difficult but the sea level was three hundred feet lower as well. Yet that passage could be forced even today. There is truly only one difficult spot after you cross the Bering strait and land alternatives might also exist. A summer trip over an ice field is not impossible if it is short enough which is the inevitable problem with a mid continent route.
This item is telling us that present archaeological work has now disproved access through the ice corridor any sooner than 12,000 years ago which makes it far too late.
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First Humans Entered the Americas Along the Coast, Not Through the Ice
Evidence mounts against the traditional story of early human migration through an ice corridor
The traditional story of human migration in the Americas goes
like this: A group of stone-age people moved from the area of modern-day
Siberia to Alaska when receding ocean waters created a land bridge
between the two continents across the Bering Strait. Once across, the
giant Laurentide and Cordilleran ice sheets, which blocked southern
Alaska and the Yukon Territory in western Canada, halted the migrants'
progress. But about 13,000 years ago, the ice sheets began retreating,
opening a 900-mile-long ice-free corridor following the Canadian
Rockies. This, many researchers believe, is how the Clovis culture moved
south and colonized other parts of the Americas.
But new evidence has made that timeline hazy over the last
decade. Research shows that humans were living south of the ice sheets
before the ice-free corridor opened up. A settlement in Monte Verde, Chile, shows people had made it all the way down South America 15,000 years ago and a more recent discovery indicates that humans hunted mammoth in Florida 14,500 years ago.
Now, a new study by an international team of researchers may
finally rip the ice corridor hypothesis out of the textbooks once and
for all. Using sediment cores and DNA analysis, the scientists
reconstructed the corridor's environment. This research shows that there
just weren’t enough resources in the pass for the earliest
human migrants to successfully make the crossing.
“The bottom line is that even though the physical corridor was
open by 13,000 years ago, it was several hundred years before it was
possible to use it,” project leader Eske Willerslev, an evolutionary
geneticist from the University of Copenhagen and Cambridge University, says in a press release.
“That means that the first people entering what is now the US, Central
and South America must have taken a different route. Whether you believe
these people were Clovis, or someone else, they simply could not have
come through the corridor, as long claimed.”
(Mikkel Winther Pedersen)Nicholas Wade at The New York Times reports
the researchers looked at an area of the ice-free corridor that was
once part of a large lake dubbed Glacial Lake Peace that would have
blocked the path. The migrants would not have been able to cross the
6,000-square-mile body of water until it began to recede, an event that
would show up in the lake bed sediments in the remains of plants and
animals.
Today, that area is covered by Lake Charlie in British Columbia
and Spring Lake in Alberta. The team visited the lakes during winter,
drilling down into the lake beds to gather sediment cores.
They then applied a technique called “shotgun sequencing” to the
materials they brought up, which allowed them to date when plants and
animals began colonizing the lake bed. “Instead of looking for specific
pieces of DNA from individual species, we basically sequenced everything
in there, from bacteria to animals,” Willerslev says in the release.
“It’s amazing what you can get out of this. We found evidence of fish,
eagles, mammals and plants.”
Wade reports that the scraps of ancient DNA show how Lake Peace
receded, slowly opening the ice corridor. Grasses, sedges, birch and
willow began colonizing the edges of the shrinking lake, and as it
dried, they found evidence of bison, voles, and jack rabbits moving in
starting around 12,500 years ago. That means it’s unlikely the area
produced enough resources like food and wood for the long migration
before that date. Instead, early humans probably followed the Pacific Coast around the ice sheets when colonizing the Americas.
The study echoes another paper that came out in June. In that study, researchers
looked at the DNA of northern and southern populations of bison
concluding they did not intermingle until 13,000 years ago, meaning the
corridor was blocked till then.
Now, to complete the story of human migration in the Americas
researchers need to focus on evidence along the coast. That's tricky
since erosion, tides and now the effects of climate change make coastal archeological sites very rare.
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