Sunday, 8 May 2011

No more nano-diamonds

As many know, in the last few years the Younger Dryas (or, Greenlanf Interstadial 1, if you prefer) has received quite a bit of attention as a potential mega-catastrophe, and impact of extraterrestrial asteroid, conveniently hitting the arctic ice sheet so as to not leave behind a crater, but nevertheless being alleged to have left behind nano-diamonds around the world, climate change and extinctions in its wake (and the origins of agriculture). It made the news in Nature [pdf], was written up in PNAS in 2007, and started a race to find archaeological and palaeoecological evidence of nano-diamonds. Doug Kennett came to London to search through the archive archaeobotanical samples from Abu Hureyra in hopes of finding some with sediment that might contain these alleged forensic evidence for the devastating impact. Well, this hypothesis, despite all the hype, has quite roundly and thoroughly dismantled, through numerous studies, but which are all drawn together in a nice "requiem" by Pinter, Scott, et al., in the recent issue of  Earth Science Reviews (http://dx.doi.org/10.1016/j.earscirev.2011.02.005). For more online summary see the discussion of this article on realclimate.org.

As an archaeologist interested in the Younger Dryas for its local impacts on ecosystems and cultural adpatations, this was only ever a distraction. That there was a climatic event remains clear, and we can return to looking critically at how this is reflected locally in archaeological and palaeoenvironmental evidence. Indeed, recent focused studies on Near Eastern archaeobotany have begun to question to relevance of the YD as the key event in the origins of agriculture. Did cultivation actually start in the YD at Abu Hureyra, or can patterns on the plant remains be more parsimoniously explained as shifts in foraging? For example, an detailed rethink of the nitty-gritty of the Abu Hureyra data, has been recently published by Sue Colledge & James Conolly in Environmental Archaeology, Dec 2010. As archaeobotanical evidence increasingly points towards a slow evolutionary process of domesticated plants in the Near East as elsewhere, and a dispersed process both in space and time around the fertile crescent, it makes less and less sense to see a few potential plots of cultivated rye in the Younger Dryas as somehow dictating the direction of all changes towards agriculture over the subsequent 3000-4000 years in the greater Near East. So we need to get back the work of looking at regional environmental impacts and cultural sequences.

(on the slow domestication in the Near East and elsewhere, one might have a look at these paper from the past year:
Purugganan & Fuller. Archaeological data reveal slow rates of evolution during plant domestication. Evolution 65(1) [2011]
Allaby, et al. (2010) A simulation of the effect of inbreeding on crop domestication genetics with comments on the integration of archaeobotany and genetics Vegetation History and Archaeobotany 19(2)
Fuller (2010) An Emerging Paradigm Shift in the Origins of Agriculture. General Anthropology 17 (2): 1, 8-12 [pdf])

[posted from Jinan, Shandong]


3 comments:

Michael Balter said...

Fascinating, Dorian, but don't forget my own contribution to this literature! :-)

http://www.sciencemag.org/content/327/5964/404.summary

Dorian Fuller said...

More evidence against the impact published in 2012: http://www.pnas.org/content/early/2012/04/16/1200296109.abstract?etoc

Thomas Lee Elifritz said...

Nanodiamonds -

https://gsa.confex.com/gsa/2013AM/finalprogram/abstract_227977.htm