At the end of the Pleistocene a Younger Dryas “black mat” was deposited on top of the Pleistocene sediments in many parts of North America. A study of the magnetic fraction (~ 10,900 ± 50 B.P.) from the basal section of the black mat at Murray Springs, AZ revealed the presence of amorphous iron oxide framboids in a glassy iron-silica matrix. These framboids are very similar in appearance and chemistry to those reported from several types of carbonaceous chondrites. The glass contains iron, silicon, oxygen, vanadium and minor titanium, while the framboidal particles contain calcium as well. The major element chemistry of both the spherules and the glass matrix are consistent with the chemistry of material associated with meteorite impact sites and meteorites. Electron microscopy confirms that the glassy material is indeed amorphous, and also shows that what appear to be individual oxide particles are amorphous as well. The latter appears consistent with their overall morphology that, while euhedral, typically shows significant fracture. Based on these data, we argue that these particles are the product of a hypervelocity impact. âº A Younger Dryas “black mat” was deposited on Pleistocene sediments. âº The magnetic fraction at Murray Springs revealed the presence of iron oxide framboids. âº The framboid particles are similar to those reported from carbonaceous chondrites. âº The particles are not consistent with known cosmic dust or terrestrial materials.
Wonderul, excellent! – the Clovis/Usselo research cannot be stopped anymore. But once in a while, once per year or so, I am still protesting against the use of the term Black Mat. If I understand well this term was inherited from Vance Haynes’ Algal Mat, and has become a verbal fossil because algae were never found in it. A DARK LAYER IS NOT A BLACK MAT.
Only recently I have realised a possibly important difference between the Northamerican and the European occurrences. Most of the European ones are in the European Sand Belt, which in sickleshape was deposited around Scandinavia, from the UK, northern France, Belgium and Holland, to northern Germany and Denmark, to Poland, Belarus and northern Russia. The Northamerican occurrences are in different facies, NOT in aeolian sands. That’s a bit unexpected. One would expect that the climate around the Canadian ice cap and around the Scandinavian one had been similar.
Am I mistaken? I should like to hear about any occurrences (outside Europe – from Colombia and the US to Abu Hureyra) where the Layer is developed in aeolian sands.
Sorry, Hans, but Clovis-Usselo studies can still be stopped – and as far as the public goes, they already have been.
Denial is a powerful mental protection mechanism, and especially powerful when backed institutionally with significant money.
I don’t know the Pleistocene and intermediate global climates well enough to comment further on your observation, other than to state that at this point we may be subject to biased data – here in the US, particularly the mid-continent, we have very very little Clovis work being done, and that with little detailed observation of the soil layers.
Pierson knows South Anerica; we’ve lost contact with the African and Indian impact researchers.
My thinking at this point is that the best strategy would be to focus on finding the lake the Assiniboine were living at at that time and the nearby crater. Why?
The only thing that is going to close this “debate” (denial) is finding and firmly dating one of the craters left by the impact of one of the larger impactors.
That’s the way it worked with the KT – and that was with considerable private sector resources, a well attested global layer of impactites, and immaculate backing for the impact hypothesis.
Between the demonstration of the global layer of impactites and locating the first crater was around 10 years, with well-funded denial continuing to this day.
Other than that, for the HSI it would take at least $40,000 – $80,000, and a dedicated information exchange network, where various lunatics could not intrude.
“Black Mat” is probably like “Younger Dryas Boundary”.