Strontium-isotope stratigraphy of the type Maastrichtian and the Cretaceous/Tertiary boundary in the Maastricht area (SE Netherlands)

Abstract

The comparison of a detailed 87Sr/86Sr. profile through the Maastrichtian of the ENCI, Curfs and Geulhemmerberg quarries in the Maastrichtian type area with a Late Maastrichtian to Early Danian seawater 87Sr/86Sr curve of the Bidart (France) and El Kef (Tunisia) sections provides a useful chronostratigraphy for these quarries. The best fit yields an accumulation rate of ~ 10 cm/ka for the upper 30 m of the Maastrichtian in the composite Curfs and ENCI section. Apparently, despite diagenetic alteration, the fossils from the Curfs and ENCI quarries partly retained their original seawater 87Sr/86Sr values. 87Sr/86Sr analyses of well-preserved heterohelicids in the Geulhemmerberg E-clay support the suggested Early Danian age of this clay. They also support the suggestion that the planktic foraminifer Heterohelix globulosa survived the Cretaceous/Tertiary boundary event(s) for some 5 to 50 ka.