New correlations of marine elastic sedimentary rocks exposed within the James Boss 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 stratigraphy 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.
- K-T boundary
- PENINSULA REGION