Márquez González, ÁlvaroOyarzun Muñoz, RobertoDoblas Lavigne, Miguel Manuel DelasVerma, S.P.2024-11-132024-11-131999-01Márquez, A. et al. (1999): «Alkalic (ocean-island basalt type) and calc-alkalic volcanism in the Mexican volcanic belt: A case for plume-related magmatism and propagating rifting at an active margin?», Geology, 27(1), pp. 51-54. Disponible en: https://doi.org/10.1130/0091-7613(1999)027<0051:AOIBTA>2.3.CO;2.0091-761310.1130/0091-7613(1999)027<0051:AOIBTA>2.3.CO;2https://hdl.handle.net/20.500.14352/110528The Mexican volcanic belt has been traditionally regarded as a classic case of subduction-related calc-alkalic volcanism. However, a series of geologic, geophysical, and petrological arguments makes this simple relationship doubtful. A seismic gap beneath the belt, a large-scale mantle anomaly, a graben triple-junction domain, and the presence of volumetrically important oceanic-island basalt (OIB) volcanism throughout the belt suggest a more complex tectonic scenario involving plume- and subduction-related processes. We here propose a model involving the development of a propagating rift opening from west to east in response to plume activity. The process started in Miocene time within the western sector of the belt (Guadalajara) and gave rise to a graben triple junction and OIB-type and calc-alkalic volcanism. Extension and volcanism proceeded to the east, giving rise to progressively younger ages for the initiation of OIB-type volcanism: (1) Miocene in the west (e.g., Guadalajara), (2) Pliocene in the central zone (e.g., Michoacán-Guanajuato), and (3) Quaternary farther east (e.g., Chichinautzin). Geochemical evidence suggests that part of the modern calc-alkalic volcanism (e.g., Chichinautzin) may be derived from magma mixing between the OIB mafic magmas and silicic, crust-derived magmas. However, we do not preclude some influence of the subducting slab in the generation of other (e.g., Jorullo) calc-alkalic volcanic rocks. Our model suggests a currently unrooted upper plume attached to the subcontinental lithosphere, which defines a hot zone beneath the Mexican volcanic belt.engjournal article1943-2682https://doi.org/10.1130/0091-7613(1999)027<0051:AOIBTA>2.3.CO;2https://pubs.geoscienceworld.org/gsa/geology/article/27/1/51/206984/Alkalic-ocean-island-basalt-type-and-calc-alkalicrestricted access551.21(720)PetrologíaGeodinámica2506.21 Vulcanología