Fossil footprints reveal humans in North America earlier than previously thought
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Re: Fossil footprints reveal humans in North America earlier than previously thought
#2What are the conditions under which these footprints were made, and how have they managed to survive undisturbed for so long?
Re: Fossil footprints reveal humans in North America earlier than previously thought
#3No picture of the footprints?
Re: Fossil footprints reveal humans in North America earlier than previously thought
#4My dad used to make this argument: of all the millions of footprints that humans made, after arriving in North America, what is the likelihood that we found the very first of those footprints?
The point is, whatever evidence we find, it's unreasonable to think that evidence we've found is the first evidence that existed, so we have to assume the real arrival was a bit before that. When we had evidence of humans arriving 17,000 years ago, it was reasonable to assume humans really arrived 21,000 years ago. When we have evidence of people arriving 23,000 years ago, you have to assume people really arrived 25,000 years ago.
There may come a point, centuries from now, when our evidence feels comprehensive, at which point the error estimate can shrink. But modern archeology is barely 100 years old and most subject areas are still under-studied, so error estimates need to remain large, for now, especially for the prehistoric era. (Obviously error estimates are much smaller for the historic era, where we have a relative abundance of evidence.)
Re: Fossil footprints reveal humans in North America earlier than previously thought
#5No picture of the footprints?
NYT has photos here:
https://www.nytimes.com/2021/09/23/science/ancient-footprint...
Re: Fossil footprints reveal humans in North America earlier than previously thought
#6What are the conditions under which these footprints were made, and how have they managed to survive undisturbed for so long?
USGS describes the site as a "large playa," and the Science abstract says they were "stratigraphically constrained and bracketed by seed layers" so I interpret that to mean they were made in wet sand and buried under layers of more sand.
Re: Fossil footprints reveal humans in North America earlier than previously thought
#7What are the conditions under which these footprints were made, and how have they managed to survive undisturbed for so long?
From the NYT article about this:
> The footprints were formed when people strode over damp, sandy ground on the margin of a lake. Later, sediments gently filled in the prints, and the ground hardened. But subsequent erosion resurfaced the prints. In some cases, the impressions are only visible when the ground is unusually wet or dry — otherwise they are invisible to the naked eye. But ground-penetrating radar can reveal their three-dimensional structure, including the heels and toes.
Re: Fossil footprints reveal humans in North America earlier than previously thought
#8My dad used to make this argument: of all the millions of footprints that humans made, after arriving in North America, what is the likelihood that we found the very first of those footprints? The point is, whatever evidence we find, it's unreasonable to think that evidence we've found is the first evidence that existed, so we have to assume the real arrival was a bit before that. When we had evidence of humans arriv…
Technically true but wrong. If your oldest Facebook post is from 2015, how likely is it that you've been using the internet before 2005?! Archeologists are very smart people in their own right, some are much smarter than we are. They do consider everything that we think they haven't. Let's give some benefit of the doubt to our fellow researchers.
Re: Fossil footprints reveal humans in North America earlier than previously thought
#9My dad used to make this argument: of all the millions of footprints that humans made, after arriving in North America, what is the likelihood that we found the very first of those footprints? The point is, whatever evidence we find, it's unreasonable to think that evidence we've found is the first evidence that existed, so we have to assume the real arrival was a bit before that. When we had evidence of humans arriv…
This is actually how archeologists estimate their ranges for human habitation in an area, just with math instead of guesses. This paper isn't about that (try timing papers like [1] instead), it's about the actual radioisotope boundary dates for an actual site.
Part of the problem these LGM dates keep running into is that it's not obvious how people got here in the first place. After about 48kya, the ice free corridors close up and the ice sheets encompass most of the coastal islands as well until about 22kya when humans can get to Alaska again and 18kya when humans can easily get down the coastal routes. What would have been possible in the middle is very much still in the ??? grey area.
Re: Fossil footprints reveal humans in North America earlier than previously thought
#10My dad used to make this argument: of all the millions of footprints that humans made, after arriving in North America, what is the likelihood that we found the very first of those footprints? The point is, whatever evidence we find, it's unreasonable to think that evidence we've found is the first evidence that existed, so we have to assume the real arrival was a bit before that. When we had evidence of humans arriv…
Technically true but wrong. If your oldest Facebook post is from 2015, how likely is it that you've been using the internet before 2005?! Archeologists are very smart people in their own right, some are much smarter than we are. They do consider everything that we think they haven't. Let's give some benefit of the doubt to our fellow researchers.
Some background on this, there is a long standing back to the late 20th century - and to those of us outside the field darkly funny - controversy within this particular scientific community on when the first humans arrived, which can be broadly googled by searches for "Clovis man controversy".
Sure archeologists are very smart people, and like all other very smart people, can still be caught on the wrong side of history as new evidence piles up against existing theories.