Siliceous plankton bloom in the earliest Tertiary of Marlborough, New Zealand Available to Purchase

In marked contrast to mass extinctions and productivity crises in much of the world' oceans at the Cretaceous-Tertiary boundary, siliceous plankton thrived in earliest Paleocene seas of Marlborough, New Zealand. Five bathyal sections show no radiolarian mass extinction across a well-defined Cretaceous-Tertiary boundary but, instead, an abrupt increase of diatoms relative to radiolarians, a general increase in both groups, and an influx of spumellarians. A pronounced increase in modal quartz and SiO₂ within a 9–25-m-thick basal Paleocene interval indicates high biosiliceous productivity, the silica being derived primarily from diatoms. Enhanced upwelling in response to climatic cooling, or more efficient nutrient cycling related to sea-level changes, may explain this plankton bloom over the first 1 m.y. of the Tertiary.