Processes within magma chambers play an important role in the formation of the magmas erupted by volcanoes. The diversity of the petrographic patterns suggest that Parinacota did not have a single major magma chamber, but rather various magma reservoirs at various depths and with variable interconnection patterns. Some Ajata magmas bypassed the shallow reservoirs completely. Starting about 28,000 years ago however several different magma systems consolidated into one, probably as a result of more frequent injections of new magma and/or the accumulation of cumulates that insulated the magmatic system. The transit of the magmas through the conduit system probably takes several ten thousand years, and the residence time within magma chambers could be on the order of 100,000 years. In the case of Parinacota, there is a noticeable difference between the pre-sector collapse and post-sector collapse magmas, indicating that a large turnover of the magmatic system was triggered by the landslide. More specifically, after the collapse erupted rocks became more mafic and their composition more influenced by fractional crystallization, while the preceding magmas were more strongly affected by mixing processes. Also, magma output increased significantly, while the resting time in the magma chambers decreased. Modelling indicates that over the short term, a collapse would cause activity to stop at a volcano of Parinacota's size, and over the long term the plumbing system would change and become shallower. Also, the plumbing system of the volcano would become more permissive to denser mafic magmas after a sector collapse, perhaps explaining why the Ajata vents were active after the collapse but the magma erupted through them influenced petrogenesis of main cone magmas much earlier. The magnitude of such changes is considerably larger than at neighbouring volcano Taapaca, where a sector collapse was not accompanied by changes in activity; presumably Parinacota's shallower magma supply system made it more susceptible to the effects of unloading. The source of the Parinacota magmas is ultimately the mantle wedge above the slab of the Nazca Plate. Fluids released from the slab flux the wedge and trigger the formation of melts, with the assistance of asthenospheric material that is hotter and gets transported into the wedge. These ascending magmas then interact with the crust, resulting in extensive changes to their composition. The area in the crust where such interaction takes place is known as "MASH" or "Melting Assimilation Storage Homogenization", and it is there that the base magmas are