Zircon U-Pb geochronology and whole rock geochemistry for pre-ignimbrite volcanoes within the San Juan locus of the mid-Cenozoic Southern Rocky Mountain volcanic field, Colorado

This U.S. Geological Survey (USGS) data release provides whole rock major, minor, and trace element geochemical data and zircon U-Pb geochronology and trace element concentrations for samples from pre-ignimbrite volcanoes within the San Juan locus of the mid-Cenozoic Southern Rocky Mountain volcanic field, Colorado. Samples were collected in order to constrain the evolution of the pre-ignimbrite magmatic system.