Figure F10. Late Cretaceous-Holocene geochronologic units correlated with calcareous nannofossil zonations and with the magnetic polarity timescale. Figure modified from Shipboard Scientific Party (1997b); see text for data sources. Nannofossil datums indicated are as follows: B (base) = first appearance, T (top) = last appearance. Black bands = normal polarity, white bands = reversed polarity.