( DSDP) Site 384: the Cretaceous/Tertiary boundary, Aptian reefs and the J-Anomaly Ridge, ( North Atlantic).

Abstract

A 330.3m section drilled on the J-Anomaly Ridge consists of the following 3 major lithofacies: 1) marly nannofossil ooze, nannofossil ooze, nannofossil chalk and foraminiferal nannofossil chalk of M. Eocene to L. Maestrichtian age (50-193m). This calcareous unit contains excellently preserved foraminifers and nannoplankton in an apparently continous sequence across the Cretaceous/Tertiary boundary, as well as an excellent assemblage of radiolarians down to the L. Paleocene; 2) U. Barremian to Aptian/Albian shallow-water bioclastic (rudist) limestones with minor interbedded calcareous clays (200-325m) indicating more than 400m of subsidence for this part of the J-Anomaly Ridge in the last 105-110my; 3) below 325m highly vesicular, weathered basalt, apparently formed as subaerial or shallow-water flows. -from Authors English