Global Volcanism Program | Image GVP-07954
The locally widespread Tepic Pumice is exposed in this quarry on the NW outskirts of the city of Tepic. The zoned rhyodacitic-andesitic pumice, forming the upper half of this exposure, was erupted about 15,000 years ago and resulted in the formation of a 4-km-wide caldera at the summit of San Juan volcano. The 5.6 cu km Tepic Pumice deposit underlies the city of Tepic, the captial city of Narayit state, to thickness of 2-9 m.
Photo by Jim Luhr, 1976 (Smithsonian Institution).