The Collaborative International Dictionary
Turonian
Turonian \Tu*ro"ni*an\, n. (Geol.) One of the subdivisions into which the Upper Cretaceous formation of Europe is divided.
Wikipedia
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by the Cenomanian stage and underlies the Coniacian stage.
At the beginning of the Turonian an anoxic event took place which is called the Cenomanian-Turonian boundary event or the "Bonarelli Event".