Activity began during the Miocene; a younger eruptive stage, at the SE end of the volcanic field, occurred during the late-Pleistocene and Holocene.

Plinth Peak was also formed during the Plinth Assemblage eruptive stage and is mostly composed of prominent columnar or partly jointed lava flows.

In research for his doctorate in astronomy, Dr. Figer found reasons to suspect that the star was especially powerful and that its "past eruptive stages" might have created the glowing nebula of dust and gas around it.