Just when you thought that Holliday et al (2014) had dealt the Younger Dryas impact hypothesis a mortal blow, along comes another paper proclaiming that the hypothesis lives yet.
Kinzie et al (2014) claim that nanodiamonds are indicators of cosmic impacts and look at the evidence of nanodiamonds at the start of the Younger Dryas at two dozen sites across three continents. They find them, and argue that a cosmic impact is the only explanation.
The paper is dependent on the quality of the chronologies used to date the nanodiamond containing layers – if they are not synchronous the hypothesis of a global catastrophe fails. Some of the chronologies are woeful, for example, the age-depth model from Lake Cuitzeo. This age-depth model is based on only six radiocarbon dates over the last 30,000 years (that would be a low number for a Holocene-length core); the dates are on bulk sediment, so are potentially affected by radiologically-dead volcanic-carbon; many outliers are rejected; and one of these dates is not from the lake core, but from a nearby trench that has been stratigraphically linked to the lake core. This is not the most robust age depth model.
Rather than examining all the age-depth models, I want to look at something that caught my attention in the abstract.
Isotopic evidence indicates that YDB NDs [nanodiamonds] were produced from terrestrial carbon, as with other impact diamonds, and were not derived from the impactor itself.
Isotopic evidence from nanodiamonds! Someone must either have extracted and purified a lot of nanodiamonds or have a very sensitive mass-spectrometer. I want to know more.
More details in the body of the paper
YDB NDs were most likely formed from terrestrial carbon, based on their carbon isotopic composition (Tian et al. 2011; Israde-Alcántara et al. 2012b)
This line of evidence is important as Kinzie et al (2014) use the terrestrial origin to exclude the possibility that the nanodiamonds are the product of cosmic dust, and so must be the result of a high energy event on Earth.
Time to look at Tian et al. (2011) and Israde-Alcántara et al. (2012), both published in the high-impact PNAS.
Tian et al. (2011) examine a site in Belgium and show that the black layer supposed to mark the start of the Younger Dryas has carbon isotopic values consistent with a terrestrial source. They explicitly state that they did not measure the isotopic composition of the nanodiamonds.
Also carbon isotope measurements and C/N values were determined from the black material of the Lommel YDB layer. The nanodiamond particles in the present material could not be analyzed separately because of their small size.
Israde-Alcántara et al. (2012) do not measure the isotopic composition of nanodiamonds either. Instead they measure the isotopic composition of bulk sediment.
Sediment samples of approximately 1 cm thickness were taken every 5 cm across the critical section between 2.80 and 2.65 m and at 10 cm intervals above and below this section. These samples were quantitatively analyzed for diatoms and pollen assemblages, carbonate (%TIC), organic carbon (%TOC), bulk major-element composition, stable carbon isotopes (both organic and inorganic), organic nitrogen, MSp, NDs, CSp, charcoal, and aciniform soot.
They do, however, mis-cite Tian et al.
Cosmic NDs occur in meteorites and cosmic dust, but Tian et al. concluded that YDB NDs are not cosmic because they display δ13C abundances (−28.1 to −26.3‰) that are terrestrial.
Kinzie et al (2014) shares several authors with Israde-Alcántara et al. (2012), so they really ought to remember what analyses they ran. This is very shoddy.
Neither paper cited by Kinzie et al (2014) as evidence that the nanodiamonds are terrestrial actually offer any evidence in this direction. Kinzie et al (2014) relies on non-existent isotopic data.
@richardjtelford
Musings on Quantitative Palaeoecology 
As a PhD student, I find a strange comfort in shoddy peer-reviewed papers because I think “If that can get published, then so can I” 😉
It’s easy to get all sorts of nonsense past reviewers. If at first you don’t succeed: submit, submit, submit again. Eventually, you will get lucky. This is not a strategy for building credibility, but I know some authors who appear to have adopted this strategy. If you are in a system where academics are rated by quantity rather than quality of output, it might not be such a terrible plan in the short term.
The other strategy for publishing nonsense is to dress it up sexily and try Nature or Science where they seem to easily fall for novelty.
Richard – over at the Dynamic Ecology blog they use the term “zombie ideas” for concepts that refuse to lie down and die despite the weight of evidence. Perhaps it’s time to begin to use this for the Younger Dryas impact hypothesis? See for example: http://dynamicecology.wordpress.com/2014/05/13/is-the-notion-that-species-interactions-are-stronger-and-more-specialized-in-the-tropics-a-zombie-idea-guest-post/
Kit – it’s actually not that difficult to fool peer-reviewers because we rarely, if ever, check the veracity of every citation. It’s also not difficult to steal money from old people, but that doesn’t mean you should do it 🙂
The Younger Dryas impact hypothesis certainly looks like a zombie hypothesis. Pinter et al held a requiem for it years ago.
But we need to be careful not to quickly dismiss hypotheses when they are first proposed as there may be gaps and problems that further work can fix. We need to accept the possibility that a reanimated corpse is Lazarus rather than a zombie.
Damn, stealing from pensioners was my plan to get rich! RICH I tell you!
Well the isotope data on those sedimentary nanodiamonds should soon be forthcoming.
http://journals.cambridge.org/fulltext_content/supplementary/MAM20_S3/assets/7337/1676.pdf
http://journals.cambridge.org/fulltext_content/supplementary/MAM20_S3/assets/7337/1768.pdf
Unless of course, you don’t think sedimentary nanodiamonds exist. Then you’re good. But if your approach to hypothesis refutation consists of shoddy evidence and illucid publications on obscure aspects of the totality of evidence, or simply stomping a wiki page, you’re in trouble. I think the accusations of poor science and poor reporting and even poor discussion in this saga are equally earned and may be equally distributed.
It will of course be interesting to see the isotopic composition of the nanodiamonds at the purported Younger Dryas horizon. I don’t suppose the results would change anybody’s mind though. The cosmic crew are welded to their hypothesis despite overwhelming evidence that where was no large, climate and ecosystem changing impact at the beginning of the Younger Dryas.
I agree, but the question now has evolved into – are sedimentary nanodiamonds credible impact proxies and if so, was there an actual impact at the start of the Younger Dryas? Whatever the case, true or false, the Younger Dryas impact hypothesis has been one of the most spectacularly useful wrong hypothesis of recent history. This seems to be lost on some of its detractors, since many of their so called refutations have been wrong as well, and in some cases, spectacularly wrong. The nanodiamonds themselves come to mind.
I would disagree that the YDIH has been a useful wrong hypothesis. Contrast it with Hubbell’s “Unified Neutral Theory of Biodiversity and Biogeography” which posits that all species within a guild are functionally equivalent. Many of the patterns ecologists thought were ecologically interesting can be the result of neutral processes, so considerable work went into testing how important neutral processes are in ecology. The UNTB is almost certainly wrong, at least in its pure form, but it had a major influence on ecological thinking and is a useful null model.
The YDIH is only important if you are interested in nanodiamonds and other putative impact debris. It may provoke research that will increase understanding there. Otherwise it is virtually irrelevant, provoking elegies rather than research. While the factors that initiated the YD may not be well understood, such cold transitions were common during the glacial period so there is no need to invoke special mechanisms such as an impact hypothesis. Only the extreme persistence of the authors (and connivance of editors at PNAS) has kept this hypothesis alive.
Only the extreme persistence of the authors (and connivance of editors at PNAS) has kept this hypothesis alive.
And the independent confirmation of the existence of nanodiamonds in terrestrial sediments coincidentally at the Younger Dryas boundary, and nuclear proxies in the Gulf of St. Lawrence that seem to support discharge flows at the Younger Dryas, etc. and the Moorhead phase low stand of Glacial Lake Agassiz, etc., evidence that either you are ignorant of or choose to ignore.
I guess you can include the Journal of Geology in your list of conspirators and connivers. Now I don’t believe for a minute that a huge impact kicked off the Younger Dryas, but I can elaborate on a host of plausible scenarios that can initiate a flood that could have initiated a series of feedbacks that in theory could have kicked off the Younger Dryas. I’m not claiming that is the case, but I would rather spend my own valuable time trying to knock down that hypothesis with credible experimental techniques, rather that trying to justify a series of peer reviewed spectacularly wrong hand wavings away of evidence that thus far has passed for disagreement with a hypothesis, and thus far have not passed the test of time. You need to prove that these nanodiamonds do not exist, or that they are not impact proxies, or that they do not indicate a large impact at the start of the Younger Dryas. Thus far your efforts have been pathetic.
Please give citations or links to the evidence you discuss, I don’t specialise in North American palaeoclimate studies so I omit to read some of the hundreds of papers published each year. I understand that some of those who read this blog read even fewer papers than I and would undoubtedly appreciate pointers towards the most convincing evidence for the YDIH.
I am happy to accept that nanodiamonds exist, and can be found (sometimes) in levels that (might) correspond to the start of the YD. But that is a long way from accepting that there was a large impact at the start of the YD that caused widespread ecological and climate change. If you want to convince me otherwise, show me the crater or explain how a bolide large enough to have a large effect can have no crater.
Hi, Actually the western united states is over an impact site 1600 miles across. There was at least 3 and looks like 4 impacts that moved the continents over the mantle. The first impact was above India and blew Eurasia half way around the world. America slid over the India impact site, hiding it from the world until now. I do not have the impact dynamics they would need to be worked out by others. The impacts and after math I have found is the most compressive explanation for all the unusual occurrences at the younger dryas boundary.
Hmm. Might be difficult to explain the palaeo-magnetic data, but otherwise this is about as plausible as other versions of the YDIH.
Well first off it can obliquely hit the Laurentide ice sheet or the ocean. QED. Impacts that can form nanodiaomonds – carbonacaous on ice or water, carbonaceous, stony or iron on limestone or coal. Nanodiamonds from atmospheric carbon dioxide in air bursts is still an open question.
The rest of this subject is hilarious. Most of the nanodiamond work has been done in the last few years, you can google scholar it. Nanodiamonds are formed by chair folding and boat buckling of the carbon or graphite by either impact, atomic, nanoscopic, mesoscopic or macroscopic. The enthalpy or formation is enormous, these are carbon – carbon bonds we are talking about. Thus they can also be formed by a CVD type process at high temperature in the presence of hydrogen and catalysts. As such they could certainly be formed by carbonaceous bolides in airbursts.
Claims that sedimentary nanodiamonds don’t exist – spectacularly wrong.
Claims that the nanodiamonds must be lonsdaleite to be considered impact diamonds – spectacularly wrong.
Claims that nanodiamonds are confused with carbon sheet forms – spectacularly wrong, we now know that if they were NOT associated with carbon sheet forms that would be extraordinary, and that the carbon sheet to nanodiamond transformation is reversible.
I can go on and on, every single refutation of the nanodiamond result has been spectacularly wrong.
Things that the refutations got right – the black mats. That’s about it as far as I can tell. I could not care less about the biological implications of a possible impact at the Younger Dryas, since I’m not particularly convinced yet that any impact occurred, and if it did it certainly was not regionally catastrophic. But the nanodiamond work resulting from this hypothesis has been spectacularly successful and highly technologically relevant. Unfortunately we do not yet have tons and tons of extraterrestrial carbonaceous materials yet to perform nanodiamond extractions and studies on, but we may have in the future. But what we do have are large amounts industrial and sedimentary nanodiamonds and these questions are about to be resolved in the near future with the atom probe spectroscopy techniques that I have provided to you. Hopefully this will be definitive. And the experimental laboratory work on nanodiamonds has been nothing less than spectacular.
As far as any possible Younger Dryas impact is concerned, for it to be hydrologically relevant to the Younger Dryas, it would have had to occur in the north Lake Superior region, and this is a region where many unanswered questions remain about Laurentide ice sheet decay, proglacial lake discharge and acoustic and sedimentary Great Lakes basin topography and stratigraphy.
So next time you diss an interesting but possibly wrong hypothesis, feel free to think about this.