Multiple geochemical and petrological studies demonstrate that the chemical composition of volcanic and magmatic rock changes dynamically as magma ascends through the crust, driven by processes such as fractional crystallization, assimilation, and magma mixing.
The retrieved papers consistently support the claim that volcanic and magmatic rock/melt compositions change during ascent. Papers [0], [3], [4], and [5] provide direct empirical evidence showing that fractional crystallization, crustal assimilation, and magma mixing alter the chemical composition of magmas as they travel toward the surface. None of the papers refute this well-established geological principle.