LONG-LIVED MAGMATIC PHASES AT LOS-AZUFRES VOLCANIC CENTER, MEXICO

Authors
Citation
E. Pradal et C. Robin, LONG-LIVED MAGMATIC PHASES AT LOS-AZUFRES VOLCANIC CENTER, MEXICO, Journal of volcanology and geothermal research, 63(3-4), 1994, pp. 201-215
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geology
ISSN journal
0377-0273
Volume
63
Issue
3-4
Year of publication
1994
Pages
201 - 215
Database
ISI
SICI code
0377-0273(1994)63:3-4<201:LMPALV>2.0.ZU;2-2
Abstract
The Los Azufres volcanic complex has had a long eruptive history of ap proximately 1.5 Myr or more (less than 3 Myr), subsequent to the build ing 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, fol lowed basaltic volcanism. Such a magmatic evolution suggests successiv e emptying of a shallow reservoir in which differentiation previously occurred. About 0.6 Ma, major deep magma supplies were probably respon sible for the resurgent doming which led to uplift of the southern par t of the caldera. From approximately 0.6 Ma to Present, the second per iod exposes volcanic products grading from basalts to rhyolites. Consi dering the recent age of the last ignimbrites (26,000 to 29,000 years) , one can assume that the volcanic activity related to a voluminous di fferentiated magma body at shallow depth has not yet ended, especially in the southern area, in and around the resurgent zone occupied by th e geothermal field.