塞兰特期（亦被称为古新世中期）是古新世的第二个阶段，起止时间分别为61.7 ± 0.2百万年前和58.7 ± 0.2百万年前。该阶段处于达宁期和赞尼特期之间。

• GeoWhen Database - Selandian

The Selandian is in the geologic timescale an age or stage in the Paleocene. It spans the time between 61.6 and 59.2 Ma. It is preceded by the Danian and followed by the Thanetian. Sometimes the Paleocene is subdivided in subepochs, in which the Selandian forms the "Middle Paleocene".