2.08 ± 0.02 million years ago the rhyodacitic Galán ignimbrite proper was emplaced. Aside from a facies that remained inside the caldera and is minimally thick, ignimbrites extend outside of the caldera to distances of but with an average runout distance of and have thicknesses of ; closer to the caldera it has been largely eroded away and there are more complete exposures farther away from Galán. A contrary view is that the Galán ignimbrite was largely eroded only on its northern side by wind action, forming yardangs. The resurgent dome consists of Galán ignimbrite material, along with basement rocks. The Toba Dacitica outcrop away from the volcano was once considered part of the Galán eruption but later compositional differences were found.