Cordilleran Section - 108th Annual Meeting (29–31 March 2012)

Paper No. 3
Presentation Time: 08:30-18:30

CUEXCOMATE: FROM THE SMALLEST VOLCANO TO THE BIGGEST GEYSER ON EARTH


BERALDI-CAMPESI, Hugo, Institute of Geology, UNAM, Ciudad Universitaria, City, 04510, Mexico, hberaldi@unam.mx

Completely surrounded by urban development in the city of Puebla, Mexico, the Cuexcomate sinter cone deposit has been mistakenly considered as a ‘small volcano’ by the local population for centuries. Its local name of ‘The smallest volcano of the world’ was coined because of its overall exterior cone-shape and its central crater. The Cuexcomate sinter cone has ~23 m in diameter, stands 13 m above the ground, and its ~4-8 m-diameter internal crater goes down ~4 m below ground (total depth ~17 m). Ambient-temperature water still flows in its interior, at the bottom floor, through a natural underground discharge, for which the path is unknown. Although no absolute ages have been obtained from this sinter, historical documents suggest and age of ~1060 years and correlate its formation with a peak in volcanic activity of the Popocatepetl volcano (~40 km to the West of the cone). The Cuexcomate had indeed a hydrothermal origin and can be compared in shape (not size) and composition to analog, currently-active geysers in the northern section of the Mexican volcanic belt, that are almost identical in composition to the Cuexcomate (90 % amorphous silica).