Proceedings of the Ocean Drilling Program, 130 Scientific Results

The role of calcareous nannofossils in building age models for Cenozoic marine sediments: a review

“…Over the past 60 years bio-magnetostratigraphic data have been, and remain, a powerful tool in establishing Cenozoic age estimates of calcareous nannofossils in marine sediments (e.g., Backman and Shackleton 1983;Backman 1986;Olafsson 1991;Gartner 1992;Agnini et al 2007). Once calibrated to magnetostratigraphy, biostratigraphic data are commonly and successfully applied to generate age models in marine sediments lacking magnetostratigraphy (e.g., Kroenke et al 1991;Curry et al 1995). In contrast, interpreting magnetostratigraphic data without guidance from biostratigraphy may result in huge discrepancies: an example being the result from ODP Site 690 in which, at the identical level, biostratigraphy suggested an age of 57.8 Ma whereas magnetostratigraphy suggested an age of 44.66 Ma, "constructed without recourse to biostratigraphic data" (Shipboard Scientific Party 1988).…”

The Late Miocene Biogenic Bloom : A globally distributed but not an ubiquitous event

“…The alternative hypothesis is the redistribution of nutrients caused by changes in oceanic circulation. Based on microfossil and δ 13 C studies, Berger et al (1993) suggested that an amplification of North Atlantic Deep Water (NADW, Wright and Miller (1996)) brought more nutrients into the Pacific Ocean, although Farrell et al (1995) rather suggest no temporal link between NADW evolution and the LMBB. The restriction of the Central American Seaway may have played a role in the redistribution of nutrients by changing oceanic circulation patterns (Pisias et al, 1995;Farrell et al, 1995).…”