Third-day road log: From Las Cruces to Rincon Hills via I-25
— Greg H. Mack, James Witcher, and Thomas Giordano

The third day of the field conference is dedicated to economic geology and will only last a half day in order to provide ample travel time for those participants who live far from Las Cruces. Consequently, participants may wish to drive personal vehicles and leave directly from Stop 3. Adequate parking is available and the road is well maintained. All three stops of Day 3 are in the Rincon Hills, a late rift (latest Miocene-Pliocene) fault block whose eastern part juxtaposes latest Oligocene-Miocene Hayner Ranch and Rincon Valley Formations against the Plio-Pleistocene Camp Rice Formation (Seager and Hawley, 1973).

Stops 1 and 2 involve short hikes to see features associated with a recently discovered geothermal field, including siliceous alteration of the tluvial lithofacies of the Camp Rice Formation and an opal bed within the Camp Rice Formation. Stop 3, located a few miles from the first stop, also involves a short hike to a quarry, where barite and manganese were mined on a small scale. This ore deposit within the latest Oligocene-early Miocene Hayner Ranch Formation will be examined and compared to other rift-related ore deposits in southern New Mexico.