Due to its
unique location, the Jemez Mountains volcanic field has been the most
productive source of Quaternary volcanism in New Mexico (Dunbar,
2005). This area is best known for the two eruptions of the Valles Caldera
at 1.61 and 1.22 Ma, which produced the lower (Otowi) and upper
(Tshirege) members of the Bandelier tuff, and made the Valles Caldera
one of the largest silicic volcanoes of the Late Cenozoic in the United
States