Here again in Switzerland, in keeping with the cognitive dissonance of the Skeptics, are supportive findings from researchers not previously published with or collaborating with the Younger Dryas boundary team. These reports are typical of others at conferences concerning the Pleistocene-Holocene transition and the Younger Dryas. Similarly supportive research appears regularly in such forums but somehow escapes the playlist of the critics. (The Tusk is working on a comprehensive list of independent-but-seemingly-invisible studies which I will post in the next few weeks.)
Elevated iridium values, dated to start of the Younger Dryas cooling event, have been found in sediments deposited at a number of Late Glacial sites in North America and one in Europe. It has been proposed (e.g., Firestone et al., 2007, PNAS 104: 16016-16021) that this widespread iridium enrichment signal is the result of an explosive disintegration of a large extraterrestrial object over North America around 12,900 cal. yr BP, and it is contended that it was this event which instigated the Younger Dryas cooling. This scenario is controversial, and the ‘ET’ explanation of these geochemical signals is not universally accepted. This notwithstanding, we report here the finding of an iridium anomaly in the Allerød-Younger Dryas boundary sediments at Hawks Tor in the southwest of England.
The concentration of iridium and other elements is determined in peat monoliths using ICP-MS, operated in collision-cell mode, and ICP-OES instruments. We find an increase of over 300 % in the iridium concentration measured in the bulk sediment immediately above the Younger Dryas boundary compared with the values found below the transition. The iridium-titanium ratio is used to confirm a lag between the start of the iridium enrichment and the timing of abrupt environmental disruption at the site signalled by decreases in the organic carbon content, and changes the concentrations of potassium, iron and manganese. These geochemical changes coincide with a shift from a humified peat to a minerogenic lithology. By using a new calibration of existing 14C ages, integrated with new AMS dates and optically stimulated luminescence ages, we show that the timing of this iridium enrichment found in southwest England is in agreement with the dates proposed for the iridium enrichment signals previously found in North America and Belgium.
Annelies van Hoesel
Hans van der Plicht
Martyn R. Drury
Nanodiamonds make up one of the important lines of evidence for the controversial hypothesis that an extraterrestrial impact took place at the onset of the Younger Dryas. These nanodiamonds have been found in the Allerød-Younger Dryas boundary layer or ‘black mat’ in North America, a section of the Usselo palaeosol in Belgium and in samples from the Greenland ice sheet. Nanodiamonds are known to occur in association with known impact events and within meteorites. However, the use of nanodiamonds as diagnostic evidence of an extraterrestrial impact is still debated. Concerning the Allerød-Younger Dryas boundary layer it has been suggested that the nanodiamonds accumulated over time from meteoritic rain or possibly formed during intense forest fires. In addition, it has been claimed that the nano-crystalline carbon in the North American black mat is graphene and not diamond.
We have sampled the previously investigated Usselo layer in detail at two classic locations in the Netherlands, Aalsterhut (near Geldrop) and Lutterzand. Several individual charcoal particles of the Aalsterhut Usselo layer have been AMS dated to assess the variability in age in the Usselo layer at this location. Samples are analysed for the occurrence of nanodiamonds using electron microscopy. In addition, samples from modern wildfires and controlled heating experiments will be analysed for nanodiamonds to investigate possible non-impact related origins of the nanodiamonds.
In the samples from the Usselo layer at Aalsterhut, we have found nano-crystalline carbon aggregates with selected area electron diffraction patterns similar to nanodiamond.
Pretty intriguing, huh? And how ironic to come right on the heels of the personal trashing given Allen West in a recent blog. Kind of a back-to-the-science drum roll.
I feel for and admire Marshall and van Hoesal who reveal their work during a period of vicious personal criticism of the theory and its earlier proponents. I am sure it does not make it any easier to confirm extrordinary things in extraordinary places when the first folks to do so are being eviscerated as kooks, fools and charlatans (even if by a handful).
But science does have a distinguished history of avoiding being extinguished. The insistence by some that we all “move along, move along” and that “there is nothing to see here” is more foolhardy in this instance than is normally the case with idea pogroms. The Younger Dryas Boundary covers a great deal of ground — literally. If a guy in Ontario with a video camera in his backyard can add to the debate — those who wish to sweep it all away are in trouble.
But these folks were not guys with video cameras in their backyards. Ms. Van Hoesal is from Ultrecht University in the Netherlands, which seems to be a reliable authority on ancient dutch soils. You will remember this institution as the home of catastrophist Han Kloosterman’s erstwhile nemesis, Eduard Atze Koster, with whom Han had a run-in over the same Usselo black band studied again today by Van Hoesal and U-U. [Tusk Exclusive]
I’d love to be a tulip in the faculty lounge when those two generations compare field notes.
The Kloosterman layer
Recall as well that the same subterranean black stripe was also discovered to be diamondiferous by Tian, Claeys and Schryvers in their dissonantly titled 2010 PNAS paper, “Nanodiamonds do not provide unique evidence for Younger Dryas Impact.” Covered here in the Tusk. And previously found by Schryvers, et. al. in at least two European locations. Covered here.
Which begs me to ask, what is more likely, that multiple, serious, dutch and german scientists have been finding nanodiamonds in bug feces over five years, failed to identify the carbon as simple crap, and mistakenly called for a “systematic, world-wide study of the materials“? Or that smug doubters like Kerr and Scott are willing to believe anything — but the truth?
Finally, we have Mr. Marshall’s confirmation of Iridium in concentration at the Younger Dryas Boundary, but this time in Southwest England. This was more of a surprise than the previously reported nanodiamonds littering the continental low-country. For one, Iridium has never been at the top of the list of solid evidence for the Event, even for the core supporters. Apparently, it is expensive to test for and the results can swing around a lot depending on concentrations within particularly grains and such. But replication is the most sincere form of flattery, and Marshall and his team bring another fine data point to the fore.