Methane blowout during the end-Cretaceous meteorite impact?

The asteroid impact associated with the demise of the dinosaurs triggered widespread failures of continental margins around the North Atlantic and created one of the largest deposits of submarine landslides known on Earth. One might expect a large-scale release of methane hydrates into the ocean and escape of methane into the atmosphere as a consequence of such slumping. However, there is no evidence for sustained input of methane in the carbon isotope record. Gravity slumping, by itself, apparently is not effective in triggering large-scale sustained degassing of hydrate reservoirs. Initial release during slumping, producing short-term effects, cannot be excluded from the available evidence. Subsequent continued degassing and leaking of hydrocarbons on a modest scale might have contributed to anaerobic conditions over large areas of the sea floor, which could help explain reduced productivity, from bacterial destruction of nitrate at depth.