Abstract

Our understanding of the Cenozoic history of the Earth’s oceans and climate is largely derived from the fossil remains of single-celled marine organisms. In the deep-oceans these biomineralized remains are a dominant component of sea-floor sediments and provide the basis for high-resolution palaeoceanographic records spanning millions of years. Typically these are based on the geochemistry (stable isotopic and/or trace metal composition) of planktic and benthic foraminifera. Here, I present complementary approaches using the fossil remains of the dominant group of Cenozoic marine calcifying phytoplankton, the coccolithophore algae. These approaches focus on: 1) the use of exceptionally well-preserved, Lagerstätte-quality, fossil coccolith assemblages; and 2) the application of novel techniques to derive single-coccolith – and hence species-specific – trace element records from fossil assemblages. Both of these approaches can be used to better understand the coupling of Earth’s climate and biosphere during major climate transitions, such as the onset of Antarctic glaciation at the Eocene/Oligocene boundary.

Bown, P. R, Dunkley Jones, T., Lees, J.A., Pearson, P.N., Randell, R., Coxall, H.K., Mizzi, J., Nicholas, C., Karega, A., Singano, J., Wade, B.S. 2008. A calcareous microfossil Konservat-Lagerstätte from the Paleogene Kilwa Group of coastal Tanzania. GSA Bulletin 120:3-12, doi:10.1130/B26261.1.

Pearson, P. N. McMillan, I. K., Wade, B. S., Dunkley Jones, T., Coxall, H. K., Bown, P. R. and Lear, C. H. 2008. Extinction and environmental change across the Eocene/Oligocene boundary in Tanzania. Geology 36:179-182, doi:10.1130/G24308A.

Prentice, K, Dunkley Jones, T, Lees, J, Young, J, Bown, P, Langer, G, Fearn, S and Ion Microprobe Facility NERC . 2014. Trace metal (Mg/Ca and Sr/Ca) analyses of single coccoliths by Secondary Ion Mass Spectrometry. Geochimica et Cosmochimica Acta. doi.10.1016/j.gca.2014.09.041