Changes in the pelagic fine fraction carbonate sedimentation during the Cretaceous-Paleocene transition: contribution of the separation technique to the study of Bidart section

This study shows that “nonbiogenic” carbonates are important components of the pelagic carbonate even during periods of normal sedimentation. In the “crisis interval”, the biogenic carbonate production drops sharply, while calcite microparticles and carbonate macrocrystals remain almost unaffected and represent the major part of the carbonate in the earliest Danian sediments. Finally, the sediments return to a composition similar to that of the Maastrichtian in M. pseudobulloides foraminifera zone.