Iztaccihuatl, Mexico
Location: 19.2 N, 98.6W
Elevation: 17,338 feet (5,286 m)
Iztaccihuatl is about 40 miles (60 km) southeast of Mexico City. It is
in the Trans-Mexico volcanic belt. Iztaccihuatl is a stratovolcano made
of layers of viscous lava flows, flow breccias, and
tephra.
Andesite and dacite
are the common
rock types. Photograph copyrighted and provided by
Steve O'Meara
of Volcano Watch International
.
The volcano began to form about 900,000 years ago. Growth of
Iztaccihuatl was in two phases. The older phase (900,000 to 600,000
years ago) constructed a large shield volcano with a summit caldera.
Cones and lava flows erupted on the flanks of the shield. The younger
phase (younger than 600,000 years ago) consists mostly of lava flows and
pyroclastic material erupted from the summit of Iztaccihuatl and on the
flanks of the volcano. Volcanism ended about 80,000 years ago. This
photo shows Iztaccihuatl (bottom right) and Popocatepetl (top left).
Photograph copyrighted and provided by Steve O'Meara of Volcano Watch
International.
Map of Local Area
Sources of Information:
Nixon, G.T., 1989, The geology of Iztaccihuatl volcano and adjacent areas
of the Sierra Nevada and Valley of Mexico: Geological Society of America
Special Paper 219, 58 p.
Simkin, T., and Siebert, L., 1994, Volcanoes of the World: Geoscience
Press, Tucson, Arizona, 349 p.
White, S.E., Iztaccihuatl, Mexico: Volcano News, 23, p. 1-3.
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