GEOLOGIC MAP OF THE VALLES CALDERA, JEMEZ MOUNTAINS, NEW MEXICO

A detailed color geologic map of the Valles caldera and surrounding areas will soon be published at a scale of 1:50,000 by the New Mexico Bureau of Geology & Mineral Resources. The new Valles map has been compiled from all or parts of nine recently completed 1:24,000 geologic maps (Bland, Cerro del Grant, Jarosa, Jemez Springs, Polvadera Peak, Redondo Peak, Seven Springs, Valle San Antonio, and Valle Toledo) that are available at http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/home.cfm. The new map provides more detailed geology on the resurgent dome, post-caldera lava and tuff eruptions, intracaldera sedimentary and lacustrine deposits, and precaldera volcanic and sedimentary rocks than previous maps and incorporates recent stratigraphic revisions to the geology of the Jemez Mountains volcanic field. Three cross sections supported by surface geology, geophysical data and deep borehole logs (≤4500 m) show an updated view of the caldera interior and depict a modern interpretation of caldera collapse and resurgence. Inset maps show physiographic features, structural relations between Valles (1.25 Ma) and the earlier, comparably sized Toledo caldera (1.62 Ma), and the distribution of hydrothermal alteration styles, including recently documented zeolite-type alteration. Finally, a generalized model showing relations of Valles to earlier volcanic units, and showing intracaldera structure is also included.