 Probably under the influence of larger scale tectonics, magma that accumulated into a mid-crustal mush zone is eventually transferred into shallow magma chambers at depths of ; recharge events where deep magma entered the shallow magma bodies may have triggered eruptions at Galán.After eruption, a leftover pluton would have been generated inside the crust.Based on the presence of two separate populations of pumice in the Galán ignimbrite it has been inferred that there were two types of magma in the magmatic system during the Galán eruption, a larger volume of so-called "white" magma and a "grey" magma which was injected into the "white" magma pool and eventually rose above the latter.