Nelson Mountain Tuff in Equity Mine area 23. Intracaldera Nelson Mountain Tuff (dark-gray-brown) exposed in Equity Mine area, viewed from West Willow Creek (San Luis Peak quad). Steeply dipping orange-brown oxidized zone marks trace of Equity fault, along which triangular block of intracaldera rhyolitic Carpenter Ridge Tuff (light-gray; unit Tcbw) has been juxtaposed against gray-brown dacitic intracaldera Nelson Mountain Tuff (unit Tnde). Photograph by P.W. Lipman.