A widespread, slumped, redeposited, uppermost Cretaceous chalk interval, up to 60m thick, immediately below the Cretaceous-Tertiary (K-T) boundary, recognised in oil company boreholes across the central North Sea and a major hydrocarbon reservoir, we re-interpret as the result of a single, catastrophic event caused by secondary effects related to the bolide impact at Chicxulub. A thin, dark clay bed immediately above the redeposited chalks, we suggest correlates to the outcropping, Iridium rich, Danish ‘Fish Clay’, rapidly deposited after the impact. Physical effects on sea-floor sediments, caused by the K-T bolide impact, have not previously been interpreted in the North Sea.
