HR: 0830h
AN: V51G-0364    [PDF]
TI: Geology and stratigraphy of the Tacan  Volcanic Complex, Mexico-Guatemala
AU: * Garcia-Palomo, A
EM: apalomo@geologia.unam.mx
AF: Instituto de Geologia, UNAM, C.U., Mexico, DF 04510 Mexico
AU: Macias, J
EM: macias@tonatiuh.igeofcu.unam.mx
AF: Instituto de Geofisica, UNAM, C.U., Mexico, DF 04510 Mexico
AU: Arce, J
EM: arcejl@tonatiuh.igeofcu.unam.mx
AF: Instituto de Geofisica, UNAM, C.U., Mexico, DF 04510 Mexico
AU: Espindola, J
EM: jme@tonatiuh.igeofcu.unam.mx
AF: Instituto de Geofisica, UNAM, C.U., Mexico, DF 04510 Mexico
AU: Hughes, S
EM: simonhughes@mindspring.com
AF: SUNY at Buffalo, Department of Geology 876 Natural Science Complex, Buffalo, NY 14260 United States
AU: Mora, J
EM: jcmora@tonatiuh.iegofcu.unam.mx
AF: Instituto de Geofisica, UNAM, C.U., Mexico, DF 04510 Mexico
AU: Saucedo, R
AF: Universidad de San Luis Potosi, Av. Dr. Manuel Nava No.5 Zona Universitaria, SLP, SLP 78240 Mexico
AU: Escobar, R
EM: mauzimauzi@yahoo.es
AF: CONRED, Avenida Hincapie, 21-72, Guatemala, GTM 13 Guatemala
AB: The Tacan  Volcanic Complex (TVC) lies at the intersection of three important fault systems. The oldest is located west of the complex and consists of fractures and NE-SW faults affecting only granitic rocks of Paleozoic and Tertiary. The second fault system is aligned NE-SW, parallel to the TVC, while the youngest fault system is aligned N-S and crosscuts the other two fault systems. The TVC rises over a local basement of Paleozoic metamorphic rocks, early Miocene granodiorites and tonalities, and a late Tertiary volcanic sequence composed of welded green ignimbrites, and indurated block-and-ash flows (up to 100m thick). This latter volcanic sequence is likely associated with the nearby Tertiary-Quaternary caldera structures Pavincul and San Rafael. The TVC itself consists of four structures aligned in a NE-SW direction: Chichuj, Tacan , San Antonio volcanoes, and Las Ardillas dome. At least three avalanche deposits have been found around the complex all of them covered by block-and-ash flow deposits of 38,000, 28,000 and 16,000 yr. B.P. The San Antonio volcano produced a Pel‚an-type eruption dated at 1,950 yr. B.P. that may represent the youngest eruption of the complex. However, the 1950, and 1986 phreatic explosions at Tacan  volcano attests to the potential hazard to the surrounding population of 250,000 people.
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting