A comment on the latest data and analysis of the age of human footprints at White Sands got me thinking very quickly so I’m migrating those rapid fire thoughts here to check against the literature later.
Original post: Me: It’s perplexing why a person asks for a geologic explanation of something observed only to be incredulous and skeptical once an informed explanation is offered.
DB: Lately, that sounds like archaeologists arguing with any other archaeologist that has produced scientific evidence of pre-Clovis humans in North America (the criticisms of the C-14 dating of the White Sands footprints for example).
Me: sometime in the future I’ll share a small cave complex with paleo-bison bones and teeth (the bit I can identify) with what appear to be two Clovis or Folsom points in the same complex. There are also hematite pictographs with an obvious local source, not knowing their age. I’d be interested in your assessment.
I left it in context and undisturbed. And unreported; my time with the BLM has me wary of large closures (from public access) of public lands administered by federal entities. And this site is most secure as is although documentation is also important if eventually encroached upon by larger visitor counts (unlikely).
DB: The usual argument: “The Clovis people crossed the land bridge around 12,500 BP and were the first humans in the Americas”
“What about this site near the southern end of South America that is older than 12,000 BP”
“The Clovis people settled the Americas sprinting the entire way”
“What about the ?”
“Well there are no radiocarbon dates”
“Yes there are”
“Those dates are stupid and wrong!”
Me: it happens a PBS gig on the White Sands footprints was on last night, and the C dating appeared kinda sketchy, if I’m understanding their process correctly. Was the stratum of the seed location known prior to testing, and the dude preparing the samples was already primed to prove “lower stratum older” and “higher stratum newer”? And what’s the calibration sample not the seeds? And cultural competency … I’ll leave this one to inference.
Good sample collection and testing would be the field scientist not revealing which seeds come from which stratum to the testing scientist. Was this the case? And I’m curious if the thickness of each stratum and the difference separation in the column was enough to justify the 23,000 to 21,000 range of lower stratum and 21,000 upper stratum. And how many strata contains seeds? And deposition rate of the lacustrine strata, and what’s the calibration. And have paleo-seeds been collected from areas not in the footprint area, to see just how old and young other biotic materials are elsewhere on the playa. And in situ crystals of selenite (not sand), for fluid inclusions that can reveal at least a general temperature of homogenization for inorganic calibration of strata … I’m not certain weight percent salinity would be useful here. And the seeds themselves; are the seed producer species still in the area today and where else are the seeds found in contemporary lacustrine deposits at similar latitude, like the Estancia basin or even high altitude like the Plains of St. Augustin. And how about the composition of the seds – gypsum is a mineral incredibly susceptible to water – can atypically deeper permeation of atypical wetter seasonal meteoric water “float” or “upward migrate” older seeds that settled and concentrated in existing depressions like footprints, then preserved by new aeolian gypsum … This type of mechanism I’ve seen at White Sands in the interdune playas, inorganic only observed … Applied mineralogy.
This might just be omissions in the show meant to guide viewers to the conclusion of an amazing new discovery; I haven’t read abstracts. How accurate is C radio dating? My interest has been K-Ar and this is great for a general dating in million years ranges, but the potential for “resetting the clock” and contamination from other radioactive sources is known going in.
Okay, I guess I need to at least read some abstracts. I’m done.
Me: DB and another thought. Is C dating considered a final proof or is it a starting point after which coraborative data is sought? That seems an important consideration.
Me: DB you know, I’m dragging this “and what if” list out of fb comments and slapping it up on my blog for a checklist. I’m now a lot more interested than I have been in the footprints.
Another thought only tangentially related. Paleo ice coring is much sexier climatology, but how about coring the lacustrine beds in the Tularosa Basin? I can think of a half dozen ways climatology data can be drawn from this.
And back to the PBS gig. There was a segment interpreting a sloth was killed by humans revealed in the tracks and marks, seeking to indicate hunting humans have always been. But where was the impact crater of a large sloth hitting the mud after being slayed? I thought something like that would be preserved as well. Linear grooves interpreted as barrow transportation for butchered meat was also explored in the PBS gig, including a track groove morphology experiment on the shores of Elephant Butte. If a ground sloth was slain at that spot, more indications of a struggle should be present … Perhaps the sloth passed through and a few hours later humans strolled by, and the non-linear human tracks indicate stepping around really big ground sloth shit, because I must believe humans of any era avoided stepping in shit.