Annual Fall Field Conference
Geology of the Ouray-Silverton Area
september 27-30, 2017

Every fall since 1950, the Society has held a field conference to some part of New Mexico and, in some cases, to border states. From the beginning, the conference has been accompanied by a guidebook with detailed road logs as well as peer-reviewed papers relevant to the region. These guidebooks remain as invaluable references to the geology of the conference study area and most are available for purchase.

Widespread enthusiasm for the Fall Field Conferences has led to receipt of many proposals for future conferences. Therefore, the schedule of upcoming field conferences is now outlined for the next several years. The field conference venues and names of organizers are listed below. All members are encouraged to volunteer assistance to the organizers or to contribute to the guidebooks. If you live near or are involved with the geology in the vicinity of the future conference sites, please consider contacting one of the organizers.

2017: Ouray-Silverton Area

Sneffels Range
Sneffels Range taken from Dallas Divide on highway from Ridgeway to Telluride
photo courtesy of Phillip Noll (

The 2017 NMGS Fall Field Conference will examine the geologic history of the Ouray- Silverton area of southwestern Colorado. Many aspects of the geologic record exposed here are similar to northern New Mexico such that “across the border” comparisons are important for understanding regional geology. Past NMGS field conferences to the western San Juan Mountains were held in 1957 and 1968, about 60 and 50 years ago. We use the 2017 conference as a retrospective of geologic advances over this timeframe and a snapshot of future research directions. Proterozoic basement exposures in the San Juan Mountains include 1.8-1.7 basement of the Yavapai province and the overlying Uncompahgre Formation, both of which may generally correlate with the Paleoproterozoic basement and Ortega Quartzite of northern New Mexico. Paleozoic and Mesozoic stratigraphic units of the SJM are uplifted to 3 km elevations in a dome-shaped uplift that borders the northern San Juan basin where correlative units are as much as 3 km below sea level.  The Laramide uplift of this range was intimately tied to development of the San Juan basin. In the Oligocene, caldera-forming rhyolite and dacite ignimbrite eruptions formed a volcanic highland with an extensive volcaniclastic apron that extended across northern New Mexico. Young (post-15 Ma) uplift and magmatism in the SJM continues to shape the topography. World class ore deposits of the southwestern Colorado reflect the same range in ages observed in the uplift and magmatic history with Laramide, mid-Tertiary, and post-15 Ma components. Quaternary geomorphology involves glacial records and deep incision along the Animas and Uncompahgre rivers. The San Juan Mountains are the headwaters for radial rivers, the Rio Grande, Rio Chama, Rio San Juan, and Rio Dolores systems and snowpack variations dramatically influence surface water supply for the Four Corners region. Human history involves early native populations, a historic gold rush, and present day skiing and recreation communities. This area has been called the Switzerland of Colorado for good reason—it provides an excellent and diverse geologic region for the NMGS 2017 field conference.

Call For Papers

(PDF version available)

We are seeking guidebook manuscripts for mini-papers and technical papers covering all aspects of geology in and around the San Juan Mountains. Please read our Instructions for Authors and contact technical editors as soon as possible if you wish to submit a manuscript:


  • Peer-reviewed technical papers – March 1, 2017
  • Mini-papers – February 1, 2017

Conference organizers and leaders are Karl Karlstrom, David Gonzales, and Matt Zimmerer, and Matt Heizler. General logistical and technical support provided by Andres Aslan, Laura Crossey, and Lynn Heizler.


Day 0 - Pre-meeting hike near Molas Pass- Wednesday Sept 27, 2017: Led by Karl Karlstrom.
Participants will assemble at the Molas Pass trailhead on the Colorado Trail at 9 AM and hike to the Animas River, then take the Durango-Silverton historic railroad to Silverton. The geology and landforms include Animas River geomorphology, Paleozoic strata, the Great Unconformity, and the Paleoproterozoic history recorded in the Irving Formation, Twilight Gneiss, and Uncompahgre Formation.  

Day 1 - Hiking circuit around Ouray, Thursday September 28, 2017. Led by David Gonzales and Karl Karlstrom. Participants will assemble at the meeting hotel at 8 AM and hike parts of the 4.2-mile Ouray Perimeter Trail that loops through excellent exposures of Uncompahgre Formation, Paleozoic and Mesozoic stratigraphy, Ancestral Rockies and Laramide faults, hot springs, and ore deposits. The hike will allow participants to explore the fantastic geology exposed at Box Canyon Falls.  Shuttles will be provided for those not interested in hiking the entire perimeter trail.

Day 2 - Volcanism and ore deposits near Silverton and Red Mountain, Friday September 29, 2017: Led by Matt Zimmerer and David Gonzales. Participants will assemble at 8 AM in Ouray to drive to Silverton where we will recap the Precambrian and Paleozoic history and get an overview of the the volcanic and plutonic history of the western San Juan caldera complex and related mineralization. Outcrop stops include mineralized postcaldera intrusions and megabreccia near the caldera margin. Afternoon stops will emphasize breccia pipes and related high-sulfidation ore systems of the Red Mountain mining district.

Day 3 - Potential half day fieldtrips, Saturday September 30, 2017

  1. Gold King Mine spill and environmental concerns, led by: TBA
  2. Hot Springs of the Ouray- Durango area, led by Laura Crossey
  3. Old 100 Mine tour and visit to the Silverton Mining Museum, led by David Gonzales


Online, phone, and mail-in registration will be available late summer 2017.


Future Conferences:

2017: Ouray Colorado

2018: Las Cruces

2019: Raton

If you have an idea for a future field conference, please contact the President of the NMGS.

Photos From Past Fall Field Conferences

Everyone is invited to share their best digital photos of past conferences with the rest of the Society membership. Please contact the society webmaster via the 'comments' link below.