Geology of Nevado De Toluca Volcano and Surrounding Areas, Central Mexico
mch089 1 of 26 Geological Society of America Map and Chart Series MCH089 2002 Geology of Nevado de Toluca Volcano and surrounding areas, central Mexico *Armando García-Palomo, José Luis Macías, José Luis Arce Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México Lucia Capra Instituto de Geografía, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México Victor Hugo Garduño Departamento de Geología y Mineralogía, Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México Juan Manuel Espíndola Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México ABSTRACT Nevado de Toluca is an andesitic-dacitic stratovolcano of Pliocene-Holocene age located in central Mexico. The volcano is built on a complex sequence of metamorphic and sedimentary formations of Jurassic-Cretaceous age, rhyolitic ignimbrites of late Eocene age, and massive andesitic lava flows of late Miocene. In the northwest corner of the map area, on top of this basement sequence, a complex andesitic-dacitic strato- volcano, San Antonio, and a series of andesitic-dacitic domes and cones of Pliocene– early Pleistocene age were also built. The first andesitic-dacitic emissions of Nevado de Toluca occurred 2.6 Ma and continued during late Pleistocene–Holocene time contem- porarily with basaltic to dacitic emissions of the Chichinautzin Volcanic Field in the eastern parts of the map area. Volcanism in the area has been controlled by the interplay of three fault systems active since late Miocene. These systems, from older to younger, are the Taxco-Querétaro Fault System (NNW–SSE), the San Antonio Fault System (NE–SW), and the Tenango Fault System (E–W).
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