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

This review paper has been thought to emphasize the role of Biostratigraphy in Geosciences and, specifically, of calcareous nannofossils as dating tool. This group of calcareous plankton occurs in Mesozoic and Cenozoic carbonate-bearing marine sediments in all depositional settings and is routinely used for stratigraphic purposes. The importance of calcareous nannofossils in relative dating of marine sediments is due to their abundance, taxonomic diversity, rapid evolution and wide distribution in marine environments. Nannofossil biostratigraphy improved over the last few decades due to the use of accurate methods for data gathering, including acquisition of semiquantitative census data on high-resolution samples. These microfossils contribute to obtain reliable biostratigraphic classification in various time-intervals in the last 66 m.y. and often provide the key to the interpretation of other stratigraphic records. Nannofossil biohorizons can be used as control points for constructing cyclostratigraphic composite sections, and for identification of magnetostratigraphic intervals, and have provided a basis for age models subsequently developed into orbitally tuned cyclostratigraphies or used for chronological revision of polarity timescale. [GRAPHICS] .

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This paper highlights the importance of calcareous nannofossils in geosciences, specifically as a dating tool. Calcareous nannofossils are widely distributed in Mesozoic and Cenozoic carbonate-bearing marine sediments and are routinely used for stratigraphic purposes. Their abundance, taxonomic diversity, rapid evolution, and wide distribution in marine environments make them valuable for relative dating of marine sediments and interpretation of other stratigraphic records.