K/T boundary event - a compromise?

31 Aug 2010

BBC News August 30th ... the K/T boundary event, it seems, involved more than one meteorite, or asteroid strike, according to a new study in the journal Geology by Professor David Jolley at Aberdeen University. The Boltysh Crater in the Ukraine was first reported (in the west) in 2002 and scientists have now examined pollen and spores of fossil plants in the layers of mud that have infilled the crater. They found that immediately after the impact ferns quickly colonised the davastated landscape. Ferns have an amazing ability, it seems, in bouncing back after landscape fires and so much so a layer of spores are considered to be a good marker of an impact event. However, the surprise was that there was a further layer of spores one metre above the first one, and in one of those very clever explanations  that manage to keep the consensus ball rolling they say it represents two impacts several thousands of years apart. In the same crater? 

Critics of the K/T boundary event usually home in on the geology - and dating sedimentary rock layers. In the asteroid strike theory, at Chicxulub, those sediments are assumed to have been laid down quickly. This offends a lot of geologists as it represents the thin edge of the wedge. Once it is accepted that sediments could have been laid down quickly at one catastrophic event and then the same idea will eventually be transferred to the rest of uniformitarian geology - and the wedge will by then have become thick and difficult to dislodge. The findings in this study appear to be an attempt to placate both sides of the debate - a classic interpretation of the data by somebody leaning strongly towards the asteroid strike theory. However, as I have not read the full paper my cynicism might be unwarranted.