Full Title: FT26CN404. The Laramie Anorthosite Complex and Sherman Batholith: Enigmatic Magmatism and Mineralization in the Mesoproterozoic, Southern Wyoming
Price: US$700 for non-members; US$585 for professional members; US$350 for student members; US$490 for early career professional members
Leader(s): Madeline Lewis; Ron Frost; Carol Frost; Phoebe Futcher
Endorser(s): GSA Mineralogy, Geochemistry, Petrology, and Volcanology Division
Industry Track(s): Economic Geology
CEUs: 2.0
Date(s): Thu.–Sat., 8–10 Oct. 2026
Departing Location: Colorado Convention Center, Denver, Colorado, USA
Start Time (first day): 2–4 p.m.
End Time (last day): 5 p.m.
Description: For over a century, geologists have debated how rocks composed of >90% plagioclase develop to form massif-type anorthosites. This field trip examines these long-standing questions using the well-exposed Mesoproterozoic Laramie Anorthosite Complex in southeastern Wyoming, one of the most accessible and well-studied anorthosite systems in the world.
Participants will visit exposures of the anorthosites and associated intrusions, including monzonitic plutons and the Sherman Batholith ferroan granite. The trip draws on decades of field, geochemical, and geochronologic work, including recent synthesis from a forthcoming GSA Memoir led by Ron Frost. We will also consider the economic geology impacts of the complex through visits to critical mineral deposits, including the Red Mountain pluton rare earth element deposit.
The trip is intended for participants of diverse backgrounds, including students, early-career scientists, and experienced researchers. The trip will be based out of Laramie, Wyoming, and includes round-trip travel to Denver. We will begin with an afternoon pickup in Denver, stop at the Virginia Dale ring complex (time permitting), and travel to Laramie. The following day focuses on exposures of anorthosite intrusions in Sybille Canyon, where we will examine multiple anorthosite units and associated critical mineral deposits. The final day highlights the Sherman Batholith before returning to Denver in the early evening.
Considerations: This trip includes short hikes (~0.5 mi) that are off trail on steep and uneven slopes. Accessible options (minimal walking, near the vehicles) will be available if needed. The majority of stops are either road cuts or accessible directly from the vehicles. The longest time in vehicles will be ~2.5 hours on the trip to and from Denver, with breaks added as needed. The longest time in vehicles when stops are not available is ~1 hour. Restroom availability during the field days will be primitive, with occasional pit toilets and frequent opportunities for outdoor cover.
We will provide water, lunches, and snacks for the field days. Lodging, breakfast, and dinners during the trip will be in Laramie, Wyoming. Stops will be between 6,000 and 8,000 ft in elevation. Participants sensitive to high elevations should exercise caution, and all participants should stay well hydrated. October weather in Wyoming can be severe, with high winds and temperatures that may drop below freezing. While we are hoping for mild weather (average October highs are in the low 50s °F), attendees are encouraged to bring layers suitable for freezing conditions.
Cost includes lodging, ground transportation, and all meals.
By purchasing this item, you are buying a seat for an in-person geological field trip. This field trip is in conjunction with GSA Connects 2026. Learn more here.
For member type discounts please contact fieldtrip@geosociety.org.
Students and Early Career Professionals can apply for funding here.
Field Trips offer Continuing Education Units (CEUs). One CEU equals 10 hours of participation in an organized continuing education experience under responsible sponsorship, capable direction, and qualified instruction.
Please review these Field Safety Documents. You will be contacted to provide your consent to these forms after purchasing a field trip.
For additional information, please contact fieldtrip@geosociety.org.
Product Code: FT26CN404
Product Category: FTRIP
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