Field trip to the La Plata Mountains, led by Dr. David Gonzales (Fort Lewis College). More information coming soon!
LEADER: Dr. David Gonzales, Fort Lewis College
COORDINATOR: Jim Corken
DATE: Sunday, September 22nd.
TIME: Meet 8:30 a.m. in DoubleTree parking lot. Form carpools. Leave at 9am.
Return by 5:00 p.m.
TRANSPORTATION: 5 carpool vehicles. Drivers MUST have 4WD, high-clearance vehicles that can
carry at least 3 riders.
FEE: $15. Covers FCGS field trip insurance.
LIMIT: 5 drivers with 4WD vehicles, 15 non-driving participants.
BRING: Daypack with lunch, water, rain gear and warm layers.
REGISTRATION: Click on this link to register: https://form.jotform.com/242483708385162
WAITING LIST REGISTRATION: Click on this link to get on the waiting list: https://form.jotform.com/242538169594166
DESCRIPTION: The La Plata Mountains are one of several Late Cretaceous laccolithic complexes that were developed in
northwestern New Mexico and southwestern Colorado ~70 Ma during the Laramide orogeny. The La Plata Mountains
straddle a major regional structural boundary between the Four Corners platform and the San Juan uplift.
These mountains were created by emplacement of 70-60 Ma subalkaline to alkaline plutons into Paleozoic to
Mesozoic sedimentary rocks causing contact metamorphism and skarn formation. The intrusive rocks in the La Plata
Mountains are mostly potassic calc-alkaline to alkaline monzonite and diorite with lesser syenite and gabbro. Base and
precious metals mineralization were allied with magmatism and related thermal metamorphism. The rugged landscape
in this mountain range was created by glaciation and fluvial erosion along with numerous mass movement events.
This tour will provide a sampling of the geology in the La Plata Mountains. We will stop at various points on this
4 x 4 trip to examine intrusive masses, contact metamorphic zones, ore deposits, and recent surficial deposits. At
Kennebec Pass we will have one of the most magnificent views of the landscape and geology in southwestern Colorado.
Participants should expect unpredictable weather and hikes up to 0.5 miles at elevations up to 11,600’.