The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic.
[5] The Toarcian Age began with the Toarcian Oceanic Anoxic Event, a major anoxic event associated with marine extinctions and increased global temperatures that sets its fossil faunas apart from the previous Pliensbachian age.
[6] The Toarcian takes its name from the city of Thouars, just south of Saumur in the Loire Valley of France.
The stage was introduced by French palaeontologist Alcide d'Orbigny in 1842, after examining rock strata of this age in a quarry near Thouars.
The base of the Toarcian is defined as the place in the stratigraphic record where the ammonite genus Eodactylites first appears.