Eruptive history and geochemistry of the Little Walker volcanic center, east central California

Abstract

The Little Walker Volcanic Center, located 11 miles WNW of Bridgeport, California, was the site of intense latitic and calc-alkaline volcanism about 10 to 7.2 m. y. ago. Latitic volcanism commenced with eruption of the Table Mountain Latite from probable vents within the Center. Eruption of the Tollhouse Flat Member of the Eureka Valley Tuff resulted in initial cauldron subsidence, producing the Little Walker Caldera. Early latite lavas erupted into the caldera, but were soon followed by the eruption of the By-Day Member of the Eureka Valley Tuff, probably resulting in further collapse. The biotite-quartz latite of Fales Hot Springs then erupted on the margin of the caldera. The last pulse of ash flow volcanism was the eruption of the small-volume upper member of the Eureka Valley Tuff within and locally outside the caldera.