Biostratigraphic Value of the Large Emiliania Huxleyi (≥4 µM) Morphotype

The distribution pattern of large Emiliania huxleyi (≥4 µm) has been analyzed to evaluate its potential as biostratigraphic marker. In particular, the Highest common Occurrence (HoC) of this morphotype has been considered to approximate the onset of the Holocene, (i.e. Marine Isotope Stage (MIS) 1 and MIS 2 boundary). Twenty records previously published have been studied for this assessment. The literature published mostly covers sites located at different latitudes in the Atlantic Ocean and the Mediterranean Sea. The age models for the sediment cores utilized are consistent with the previously published studies. Comparison of the different data sets highlights a slight diachrony in the HcO of the morphotype between high and mid-latitude records. The paleoenvironmental framework of the studied cores suggests that the large E. huxleyi thrived in cool/cold surface waters. Therefore, its distribution in the Atlantic Ocean and Mediterranean Sea varies in relation to surface water masses and hydrographic fronts. Overall, the HcO of large E. huxleyi appears to be a useful marker for the Holocene onset, although further evaluation across different marine regions would be valuable. In addition, extending this analysis to last climatic cycles could reveal a similar pattern across other glacial/interglacial transitions.