Calcareous nannofossils in the Western Mediterranean during the Early-Middle Pleistocene transition

Taxonomic analyses of coccolithophore assemblages have been carried out on sediments from Ocean Drilling Program Site 975 in the Algero-Balearic basin (38°53.8′ N, 4°30.6′ E), through late marine isotope stage (MIS) 20-19 (from 800 to 756 thousand years ago). Quantitative analyses on coccolithophores were performed at the Dipartimento di Scienze della Terra e Geoambientali, Bari University (Italy), using a polarized light microscope at 1000 X magnification, and abundances were determined by counting at least 500 coccoliths of all sizes. Nannofossil dissolution index (DI) has been calculated as follows: small gephyrocapsids/(small gephyrocapsids + Calcidiscus leptoporus).