1. An age in the Early Permian Epoch, preceded by the Stephanian, Gzelian, and Noginskian (Carboniferous), followed by the Sakmarian, and with an initial boundary (the Carbo–Permian boundary) dated at 290 Ma ( Harland et al., 1989).
2. The name of the corresponding eastern European stage which, because of lower boundary uncertainties, has also been considered as part of the Carboniferous system. It is roughly contemporaneous with the lower Wolfcampian and lower Rotliegende (western Europe), and with the lower Somoholoan (New Zealand). See also SAKMARIAN.
"Asselian." A Dictionary of Earth Sciences. . Encyclopedia.com. (September 23, 2018). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/asselian
"Asselian." A Dictionary of Earth Sciences. . Retrieved September 23, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/asselian