Crustal assimilation at depths of more than was involved in the formation of the dacitic magma and contributes about 18% of the mass of the dacites. Taapaca is constructed on a fairly thick crust and rising magma, and thus undergoes substantial interaction with the crust, meaning that crustal contamination is important in the genesis of Taapaca's magmas. This magma is then transported to shallower levels, where it crystallizes.