The Salt River is known mostly as a dry gravel bed through metropolitan Phoenix but upstream from there it is a living, vibrant stream. Near where US Highway 60 crosses the Salt River between Globe and Show Low, the river arcs beneath cliffs cut into the Proterozoic Apache Group, composed of sedimentary rocks and lavas. The gold colored layers on the right and in the road cut (upper left) are part of the Dripping Springs Quartzite. The darker rocks near the rivers edge are intrusive diabase emplaced as a sill within the quartzite. The quartzite was already in place when the igneous rocks intruded them. These intrusions caused the formation of serpentine asbestos (chrysotile) along the contact and this was commercially mined in the Salt River Canyon during the early years of the 20th century. (photo by Wayne Ranney)
Online resource: Skotnicki, J. S., 2002, Geologic Map of the Sierra Ancha, Central Arizona: Arizona Geological Survey Digital Geologic Map DGM-24, version 1.0, map scale 1:24,000, 31 p., 2 map sheets http://repository.azgs.az.gov/uri_gin/azgs/dlio/491
