The late middle Eocene radiolarites of Hole 1219A are composed of taxa belonging to radiolarian Zones RP-16 (Podocyrtis goetheana Zone), RP-15 (Podocyrtis chalara Zone), and RP-14 (Podocyrtis mitra Zone). Based on age calculations using data from the multisensor track (Pälike et al., this volume), the diatom-rich unit was deposited ~1.8 m.y. ago (39.554–41.358 Ma).
Linear sedimentation rates for Hole 1219A of ~4.8 m/m.y. indicate the end of a 4-m.y. period of relatively fast sedimentation (Shipboard Scientific Party, 2002). Bulk mass accumulation rates (MARs) are very high at ~41 Ma. MARs of silica for Hole 1219A peak at 41 and 43 Ma, corresponding to both of the middle Eocene diatom intervals.
The basal part of the diatom-rich unit in Zone RP-15 corresponds to the base of the lower Si MAR peak, and the middle part of Zone RP-15 shows stepwise decreasing Si MAR. A similar trend can be recognized at Site 1218 and, with weaker intensity, at Site 1217 (Shipboard Scientific Party, 2002).