Day 2 Road Log from Ouray to South of Animas Forks Via Silverton: Geology Along the Million Dollar Highway and of the Western San Juan Calderas
— M.J. Zimmerer, D.A. Gonzales, and K.E. Karlstrom

Day 2 of the 2017 NMGS Fall Field Conference focuses on the volcanic, intrusive, and mineralization history of an Oligocene caldera cluster in the western San Juan Mountains. Our out-and-back route (Fig. 2.1) starts from Ouray on the famous Million Dollar Highway, climbs Red Mountain Pass, and traverses to a pleasant view above the town of Silverton. At Stop 1, we will discuss the regional geologic setting of the Silverton area including an introduction to caldera processes, a summary of volcanism in the Southern Rocky Mountain volcanic field (SRMVF) with emphasis on the western San Juan caldera cluster and the geomorphology of the region. A short drive takes the caravan to Stop 2, where we will examine outcrops of the Sultan Mountain stock and remnants of the Champion mine. Stop 2 offers the first opportunity of the day to collect mineral specimens. The incredibly scenic (and somewhat bumpy!) drive from Stop 2 to Stop 3 passes through the town of Silverton and north along the Animas River Valley. Stop 3 is focused on examining the intracaldera tuff within the San Juan-Uncompahgre caldera complex and the formation of caldera-collapse breccia deposits. The caravan will then retrace the route back to Silverton and then to Red Mountain Pass for the fourth and final stop of the day. At Stop 4, we will continue our discussion of caldera-hosted mineral deposits, specifically those related to ~24 Ma breccia pipes of the Red Mountain mining district. Field trip participates are invited to collect mineral specimens at this stop as well.