Stable carbon and oxygen isotope record of Maastrichtian sediments from DSDP Site 74-528 in the South Atlantic Ocean

The isotopic record of this sequence indicates that relatively large (0.5-1.0‰) late Maastrichtian oxygen and carbon isotopic shifts occurred on geologically short time scales (less than 100-500 kyr). Comparison with previous oxygen isotopic data suggests that in high- and mid-latitude southern oceans the multimillion-year Maastrichtian cooling trend largely resulted from geologically rapid climatic 'steps'.

Coincidence of the largest carbon and oxygen isotopic excursions suggests that relatively large and geologically rapid changes in marine and atmospheric carbon content may have directly contributed to the long-term cooling of the Late Cretaceous 'greenhouse'.