Long-lived magmatic phases at Los Azufres volcanic center, Mexico.

Abstract

The Los Azufres volcanic complex has had a long eruptive history of approximately 1.5 Myr or more less than 3 Myr, subsequent to the building of a large Miocene and Pliocene andesitic complex. Since about 1.5 Ma, its development consists of two main periods of volcanic activity. The first period, from approximately 1.5 to 0.8 Ma, had two magmatic cycles, about 200,000 years in duration, characterized by acidic, followed basaltic volcanism. Such a magmatic evolution suggests successive emptyings of a shallow reservoir in which differentiation previously occurred. About 0.6 Ma, major deep magma supplies were probably responsible for the resurgent doming which led to uplift of the southern part of the caldera. From approximately 0.6 Ma to Present, the second period exposes volcanic products grading from basalts to rhyolites. Considering the recent age of the last ignimbrites 26,000 to 29,000 years, one can assume that the volcanic activity related to a voluminous differentiated magma body at shallow depth has not yet ended, especially in the southern area, in and around the resurgent zone occupied by the geothermal field.

23 samples from this reference