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

Abstract

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. Graphic abstract

Uncertainties surrounding the oldest fossil record of diatoms

“…The DSDP 416A Initial Report site description and drilling information collected during the expedition suggested possible downcore sediment movement during drilling and recovery 28 . Coccolithophores, which are routinely used in the stratigraphy of Mesozoic and Cenozoic sediments 31 , were used to evaluate the age of our samples. The 416A chert samples contained coccolithophores from both Mesozoic (e.g., Watznaueria and Manivitella ) and Cenozoic (e.g., Discoaster and Toweius ) Eras indicating probable mixing of the microfossil assemblages and thus preventing accurate age assignment to these samples.…”

Calcareous nannofossils biostratigraphy of well Uche 1, Offshore Lagos, Eastern Dahomey Basin, South Western Nigeria

“…Despite this, it is generally assumed that nannoliths had algal origins as they show closely-comparable distributions to coccoliths and many display only slight morphological modifications to the basic coccolith plan. Due to their great abundance, photosynthesis and calcification, haptophyte algae are significant components of the earth's biogeochemical cycles [3]. The evolution of nannoplankton resulted in a major shift in the locus of global calcification from the continental shelf towards deep oceans, with the accompanying effects on deepocean CO2 budgets, calcite compensation depths and geological carbonate turnover rates.…”

Middle Eocene Nannofossil Assemblages Responding to Depositional Dynamics of the Elat Formation, Maluku

“…Pelagic carbonate rocks as the Elat Formation usually contain many nannofossils (Agnini et al, 2017). These taxa are very small marine microfossils, oval, rod, star-shaped, nannofossil belongs to the protist kingdom, phylum hatophyta comporised of calcite plates generally produced by unicellular marine algal coccolithophore as a parent cell, limestone composisition, with a size of ±1-25 μm (Isnaniawardhani, 2017;Widhiyatmoko et al, 2023) Nannofossil analysis provides good accuracy in determining relative ages of marine sediment because of the abundance, rapid evolution and wide distribution (Isnaniawardhani, 2015;Raffi et al, 2022). Quantitative analysis of nannofossils can be used to support the paleo-depositional environments, Paleotemperature and oceanographic reconstructions in addition to foraminifera (Isnaniawardhani et al, 2020;Karatsolis & Henderiks, 2023;Lowery et al, 2014;Choiriah & Maha, 2020;Villa et al, 2021;Imai et al, 2013;Rosmadi et al, 2022;Alves et al, 2016;Mandur et al, 2022).…”