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Younger Dryas Update May 2013

21 May 2013

At http://cosmictusk.com/wittke_pnas_younger_dryas_clovis_comet/ … a new paper published in PNAS – George says it is the best yet. This time impact is discarded in favour of multiple airbursts by a disintegrating comet or space rock. The thrust of the article is a riposte to criticism of their methodology so they have gone back to the laboratory in order to stress the point it is all above board. They have collated an assemblage of what they say is impact related proxies – such as microspherules, nanodiamonds, and iridium. These are distributed across four continents, they say, and must reflect a global event.

Some 18 sites were investigated involving 700 separate analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analysis and scanning electron microscopy for surface microstructural characterisation.

12 known sites, as investigated so far, mark end of Pleistocene archaeology where the onset of the YD marks a hiatus in human occupation or major changes in site use. The results from the laboratory are consistent with the melting of sediments to temperatures of some 2,200 degrees C by thermal radiation and air shocks produced by the passage of a space rock, or rocks, through the atmosphere. They are also consistent with volcanic, cosmic, anthropogenic, lightning or anthigenic sources so the jury is out to some extent.

The paper, as yet, is not available to the general public and PNAS have released an abstract. George Howard was involved in the paper and he provides the full article at the web site above – but it can only be read online. It can't be downloaded or printed out. It will be fully available in due course.

Impact related burning of biomass may have contributed to spherule production and some tests were done on wood. It is estimated some ten million tons of spherules were distributed over 50 million square km.

George also provides colour photographs of the author and co-authors, which is novel in itself, as well as some biographical information just a click away. They are James Wittke, James Weaver, Ted Bunch, James Kennett, Douglas Kennett, Andrew Moor, Albert Goodyear, Christopher Moore, Kenneth Tankersley, Randolph Daniel, Jack Ray, Neil Lupinot, David Ferraro (the US) with Gordon Hillman (UCL, London), Isobel Israde-Aleantara (Mexico), James Birschiff (US Geological Survey), Robert Hermes (Los Alamos National Laboratory), Paul de Carli (SRI International), Johan Kloosterman (Amsterdam), and various others are cited including George Howard, Carl Lipo, Richard Firestone, Allen West, Sachiko Sakai, David Kimbel and Ladislave Nabelek (Czech Academy of Science) and Zsolt Revay etc.

The same story, from the abstract, can also be seen at http://phys.org/print288367533.html … and we learn that not only nanodiamonds are evidence for the YD boundary event but fullerenes, malt glas, and iridium. In addition, the event involved landscape fires and an increase in atmospheric dust load that blocked sunlight long enough to cause starvation of the large Pleistocene animal species (or those ones that became extinct).

We also learn that microspherules do not solely have a space rock event origin but can be produced by volcanoes, lightning strikes, and coal seam fires. Hence, iot was imperative to differentiate – were these impact/ airburst related, or otherwise. Hence, the scanning and analyses.

However, tests on remanent magnetism in the spherules (the remaining magnetism after the removal of an electric or magnetic influence) showed the spherules could not have formed due to lightning strikes, it is alleged. An interesting observation – for what it is worth. Experiments by the group have for the first time demonstrated that silica rich spherules can arise from high temperatures and the incineration of plants and trees (such as oaks, pines, reed beds etc). They seem to contain biologically formed silica. This is also an interesting point – what does it mean in relation to the formation of flint (possibly at the K/T boundary event) as flint is basically silica that first formed as a gel. Might that also involve plant life? The opinion of some geologists is that the silica in flint comes from ocean sponges, and in its gel like form was prone to fill cavities which included worm holes and burrows.

See also www.pnas.org/cghi/doi/10.1073/pnas.1301760110 … several comments have been added to the Phys.Org story and one person claims they have found insect droppings and identified it as impact spherules (he clearly can't imagine a space rock exploding in the atmosphere, in spite of the February meteor that disintegrated above Russia. Many of the commenters appear to suffer the same hang-up – I didn't learn this sort of stuff at school, college or university and therefore it isn't true. Lots of them are still expecting a crater – like the one found for the K/T boundary event. All this and they have only read the abstract. Over at http://cosmictusk.com George has supplied the full article and the comments are more sensible. It should be added that the Phys.Org commenters are people strong on CAGW as you only have to read what they say on climate papers. Same tendency to trust authority and to distrust maverick scientists.

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