Geology Hike: Dolores Gulch to Old Ortiz Mine

Event Description

This hike will take us “on foot” from the entrance gate on Gold Mine Road into the Preserve along the 4WD access road, to the Old Ortiz Mine and the Loop Trail.

We will discuss the geologic setting of the Ortiz Mountains and examine outcrops of pyroclastic rocks that formed in the 25-30 million year-old Dolores Gulch volcanic vent, and gold-bearing quartzite at the Florencio prospect along its margin. At the Old Ortiz Mine we can observe (but not enter) one of the earliest hard-rock mining efforts in the western United States, and discuss the 1970s-80s-era mining at Cunningham Hill, about 1 mile east of the Old Ortiz Mine. At the Loop Trail we’ll ponder the relationship of the massive augite-monzonite (a type of granite) stock to the volcanic rocks.

see website for map
4-5 hours in duration
5 mile hike