(Eucyrtidium tumidulum Zone in Hays, 1970; Artostrobium miralestensis Zone in Kling, 1973; Artostrobium tumidulum in Foreman, 1975)
Defined by the occurrence of Botryostrobus aquilonaris (Bailey) subsequent to the extinction of Stylatractus universus. This is the uppermost Quaternary Zone in middle latitudes and is equivalent to the Omega Zone in Antarctic sediments (Hays, 1965).
Events included in this zone are:
- Tm Stylacontarium acquilonium
The base of the zone is defined by the morphotypic last appearance of Stylatractus universus and is coincident with the upper limit of the Stylatractus universus Zone.
Reference slides R 50.1, R 50.2 and R 50.3 from Sample 18-173-2-2, 46-49 cm.