Aalénium 阿连期 younger bound -170.3 +|-1.4 Ma Phanerozoic Eon Aaleniense Jurassic Period Base of Middle Jurassic Middle Jurassic Epoch Aaleniën aalenij Early Jurassic Epoch Aalenien Alenis пален aaleni Geologic Time Scale (2019) álen Bajocian Age Aalenian Age Aaleniano aalen Aaleni Aalenian a1.1.2.2.2.4 アーレニアン期 Mesozoic Era aaleniano Aalen Aalen Aalen Aalen older bound -174.1 +|-1.0 Ma Aalénien Toarcian Age Base of Bajocian