At https://www.science.org/content/article/modern-blackfoot-people-descend-ancient-ice-age-lineage/ … The Blackfeet people are descended from Ice Age people. They live in a broat swathe of North America – and seem to have done so for at least 10,000 years. See the study in Science Advances at https://doi.org/10.1126/science.zkv29ik … Their genetic heritage extends back 18,000 years, it is claimed, and they are related to early migrants into the Americas. In the modern world the Blackfoot Confederacy live on the eastern slopes of the Rocky Mountains and the adjacent plains of Montana, Alberta, and Saskatchewan.
See also https://www.livescience.com/archaeology/ancient-indigenous-lineage-of-blackfoot-confederacy-goes-back-18000-years-to-last-ice-age-dna-reveals … which is basically taken from the same press release. What is interesting is that the Blackfeet people diverged at some point from other indigenous groups. The research suggests this was around 18,000 years ag0 – at the beginning of the Oldest Dryas period [immediately following the Late Glacial Maximum]. That is perhaps a hunch. They may have diverged even earlier – in Siberia.
Over at https://www.livescience.com/archaeology/8200-year-old-campsite-of-paleo-archaic-peoples-discovered-on-us-air-force-base-in-new-mexico …. a campsite dating to around 8200 years ago has been unearthed in New Mexico. Charcoal from a camp fire was used to produce a date. It coincides in time with the 6200 BC event -so what might have caused the remains. The area is close to White Sands National Park – which has an interesting geology. Gypsum sand dunes also preserved early human footprints made 23,000 years ago – not too far away. We are informed the dunes formed 1000 years after the camp site was in use, which suggests the Paleo-Archaic people inhabited the region prior to the 6200 BC event. It provides a good boundary point.
At https://earthobservatory.nasa.gov/images/39289/white-sands-national-monument/ … we are told the White Sands geology extends from the northern end of the Chihuahuan Desert in northern Mexico, as far as New Mexico in the States. Gleaming white sand dunes cover 275 miles of central New Mexico, 40% of which is in the National Park. The white sands are formed from gypsum, a soft mineral left behind when water bodies evaporate. At this link we are told the gypsum itself was formed as early as 250 million years ago. During the Late Pleistocene period, coinciding with the Late Glacial Maximum, the region was not a desert but had plentiful rainfal. Gypsum from the mountains was washed into a huge lake. When it dried out and the water had evaporated, it left behind gypsum. Then, between 6500 and 7000 years ago, the gypsum formed sand dunes [which is where the 1000 years comes from]. We may note this is probably an estimated date as we are talking about sand. Therefore, a connection with the 6200BC event [8000 + years ago] cannot be ruled out. Some clarification is necessary – but can you actually date sand dunes. If so, has that been done.