Trace metal (Mg/Ca and Sr/Ca) analyses of single coccoliths by Secondary Ion Mass Spectrometry

Katy Prentice, Tom Dunkley Jones, Jackie Lees, Jeremy Young, Paul Bown, Gerald Langer, Sarah Fearn

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)
14 Downloads (Pure)


Here we present the first multi-species comparison of modern and fossil coccolith trace metal data obtained from single liths. We present both trace metal analyses (Sr, Ca, Mg and Al) and distribution maps of individual Paleogene fossil coccoliths obtained by Secondary Ion Mass Spectrometry (SIMS). We use this data to determine the effects of variable coccolith preservation and diagenetic calcite overgrowths on the recorded concentrations of strontium and magnesium in coccolith calcite. The analysis of coccoliths from deep-ocean sediments spanning the Eocene/Oligocene transition demonstrates that primary coccolith calcite is resistant to the neomorphism that is common in planktonic foraminifera from similar depositional environments. Instead, where present, diagenetic calcite forms distinct overgrowths over primary coccolith calcite rather than replacing this calcite. Diagenetic overgrowths on coccoliths are easily distinguished in SIMS analyses on the basis of relatively higher Mg and lower Sr concentrations than co-occurring primary coccolith calcite. This interpretation is confirmed by the comparable SIMS analyses of modern cultured coccoliths of Coccolithus braarudii. Further, with diagenetic calcite overgrowth being the principle source of bias in coccolith-based geochemical records, we infer that lithologies with lower carbonate content, deposited below the palaeo-lysocline, are more likely to produce geochemical records dominated by primary coccolith calcite than carbonate-rich sediments where overgrowth is ubiquitous. The preservation of primary coccolith carbonate in low-carbonate lithologies thus provides a reliable geochemical archive where planktonic foraminifera are absent or have undergone neomorphism.
Original languageEnglish
Pages (from-to)90-106
Number of pages17
JournalGeochimica et Cosmochimica Acta
Early online date6 Oct 2014
Publication statusPublished - 1 Dec 2014


Dive into the research topics of 'Trace metal (Mg/Ca and Sr/Ca) analyses of single coccoliths by Secondary Ion Mass Spectrometry'. Together they form a unique fingerprint.

Cite this