Late Cretaceous extinction patterns in Antarctica

New correlations of marine clastic sedimentary rocks exposed within the James Ross Basin, Antarctica have shown that the mid-to late Cretaceous succession is in excess of 5 km thick. Plotting the ranges of the principal molluscan macrofossils against the revised stratigaphy indicates that inoceramid bivalves are totally absent, and dimitobelid belemnites extremely rare, throughout an extensive 1400 m thick Maastrichtian succession. These early extinction patterns are interpreted to be due to both a regional shallowing event and a pronounced phase of high-latitude, Campanian–Maastrichtian cooling. Cool polar bottom waters may have been forming by as early as mid- to late Campanian times.