130ky Cerutti site stone tools validated as made by human beings?

In April 2017 we posted about the Cerutti mastodon site in California, with its "stone tools" dated to 130,000 years ago.

An article (Raman and optical microscopy of bone micro-residues on cobbles from the Cerutti mastodon site) published this month, reports finding bone micro residues on the cobbles found next to the broken mastodon bones, suggesting that these were used as tools to break the bones open and not just a chance accumulation of stones and broken bones.

The abstract states:

"Cobbles from the Cerutti Mastodon (CM) site have impact marks and usewear suggesting that mastodon bones were placed on stone anvils and struck with stone hammers to produce two concentrations of broken bones and stones. Critics have suggested that the stones may have broken by rolling down slopes rather than in situ at the two concentrations. Our analysis of two cobbles (pegmatite CM-254 and andesite CM-281) identifies bone micro-residues that are not evenly distributed over the cobbles, and are unlikely to have been transferred from sediment or from passive contact with adjacent macro-bones. Bone micro-residues on cobble CM-254 were recovered from surfaces associated with usewear, but were absent from the naturally broken surface found in direct contact with a mastodon rib. In addition, bone micro-residues on cobble CM-281 were recovered from upward facing locations with impact marks and other usewear; but were absent on the downward facing surface. Bone micro-residues are absent in sediment away from the bone concentrations. These new data support the argument that the associated concentration of broken stones and mastodon bones is in situ, and that bones in this concentration were likely broken by the pegmatite cobble (comprising CM-254 and other fragments), when it struck mastodon bones placed on the andesite cobble CM-281. These findings add to the totality of evidence that supports human agency rather than geological processes as the driver responsible for the CM taphonomic pattern. "

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2020 by Austin Whittall © 

Archaic admixture into Africans

The article I mention in this post was published in Feb. 2020 (Recovering signals of ghost archaic introgression in African populations by Sriram Sankararaman and Arun Durvasula Science Advances 12 Feb 2020:Vol. 6, no. 7, eaax5097 DOI: 10.1126/sciadv.aax5097). It reports an " archaic introgression into four West African populations. Our analyses ... indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans".

The authors "estimate that the archaic population split from the ancestor of Neanderthals and modern humans 360 thousand years (ka) to 1.02 million years (Ma) B.P. and subsequently introgressed into the ancestors of present-day Africans 0 to 124 ka B.P. contributing 2 to 19% of their ancestry."

Could African "diversity" often used to justify the continent as the cradle of mankind be due to this introgression?

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2020 by Austin Whittall ©