A division of areological time, lasting from 1.80 Gy to the present in the Hartmann–Tanaka Model and 3.55 Gy to the present in the Neukum–Wise Model, and divided into three epochs: Lower Amazonian (1.80–0.70 or 3.55–2.50 Gy); Middle Amazonian (0.70–0.25 or 2.50–0.70 Gy); and Upper Amazonian (0.25–0.00 or 0.70–0.00 Gy).