The YD boundary event splutters once again

23 Dec 2010

The big news at http://cosmictusk.com this week is that a former critic of the YD boundary event has, out of nowhere, changed his mind - see Scribd paper available to download as a pdf document (5 pages). This turn around comes after Phil Cleays had said in a December 2009 paper (just 12 months ago) 'the geochemical story is finished; its over. There is nothing, no meteoritic signal. No one I know of has come to their defence' (see www.sciencemag.org/content/329/5996/1140.full ). Cleays was part of the orthodox ring fence, a circling the wagons strategy designed to ward off a controversial theory. In the new paper at www.pnas.org/cgi/doi/10.1073/pnas.1007695108 three Belgian scientists, H Tian, D Schryvers and P Cleays, explain how nano-diamonds were found in a black YD boundary layer at Lommel in Belgium. 'Our findings confirm, and in fact reveal more direct proof than the earlier studies, of the existence of diamond nano particles also in this European YDB layer. No such particles are found in the overlying silt and clay or in the underlying fine sands'.

The thickness and depth of the black layer varied depending on the actual location investigated along an excavated trench. It is mostly buried under 50cm of yellow clay and beneath it is a one metre thick layer of fine white sands. The black layer was analysed and was essentially composed of carbon. However, the article concludes by saying the variety of crystalline structures observed in the black YDB at Lommel does not provide sufficient evidence to conclude an oxogenic impact as the origin of these structures. Still some way to go.