Late Cretaceous Nannoplankton and the Change at the Cretaceous-Tertiary Boundary
Hans R. Thierstein, 1981. "Late Cretaceous Nannoplankton and the Change at the Cretaceous-Tertiary Boundary", The Deep Sea Drilling Project: A Decade of Progress, John E. Warme, Robert G. Douglas, Edward L. Winterer
Download citation file:
Quantitative taxonomic analyses of Late Campanian to Early Danian calcareous nannofossil assemblages suggest worldwide stable ecological conditions in the photic zone during the last 15 million years of the Mesozoic. Late Cretaceous bioprovincialism was strongly paleolatitudinal. The sudden extinction of the Cretaceous assemblages was followed by low supply of phytoplankton carbonate and by blooms of neritic taxa in the Early Danian, indicating low productivity and ecological instability. The most complete Cretaceous-Tertiary boundary record studied is at DSDP Site 356 (South Atlantic), where thicknesses of zones close to the boundary are twice those at Gubbio, Italy. The mode of calcareous phytoplankton evolution appears unsuitable for tests of theoretical evolutionary models.
Figures & Tables
At the present the Glomar Challenger has drilled over 500 holes over the world ocean, involving hundreds of scientists from dozens of countries. This volume is intended as a review of some of theimportant results from the most comprehensive, ambitious and successful earth-bound geologic project ever undertaken. The symposium upon which this volume originated was held April 4, 1979 at the SEPM/AAPG Annual Meeting in Houston. No comprehensive synthesis of all aspects of the DSDP has appeared, and the topic coverage in this volume is biased towards the sediments and fossils, and their significance for certain aspects of earth history – paleogeography, bathymetry, climatology, oceanography, ecology, environments – all in keeping with the audience of sedimentary geologists.