The formation of the Galán magma has been explained with melting of lower crustal rocks under the influence of rising basaltic magmas that supplied the heat needed for the melting processes, and which also directly contributed to magma formation through mixing events. Further metasomatism in the crust and fractional crystallization processes completed the magma genesis process. 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.