K/T Boundary

7 Mar 2010

www.physorg.com March 4th ... the asteroid impact at the K/T boundary left a clear band between light coloured Cretaceous sediments and dark coloured Palaeocene sediments (a picture of the geology is provided online), recovered from the sea floor off South America. The abrupt shift in colour reflects an instantaneous drop in ocean biological productivity. There is also an online video (including an audio interview and animated graph) of the asteroid impact, with Dr Joanna Morgan of Imperial College explaining the science. The evidence has been collated by 41 scientists in response to claims that it was volcanology in India that was responsible for the demise of the dinosaurs. These eruptions are said to have lasted for 1.5 million years - an incredible length of time - but how was it calculated? So much lava was produced it could have filled the Black Sea basin twice - but why did it take one and a half million years to do it? The panel of scientists also discounted previous studies that suggested Chicxulub (chick-shoo-loob) occurred 300,000 years prior to K/T. They say those studies misinterpreted the geology close to the impact site - they said rocks close to the impact zone underwent complex geological processes after the asteroid collision which made it difficult to interpret the data correctly. Note :- they do not suggest the geology was created instantly even though they have seen it actually happen during the Mount St Helens eruption some years ago. I suspect the story still has a very long way to run. The other side will bounce back.