Full Title: FT26CN407. A Bike Tour: Geology, Geochronology, and Geochemistry of the Table Mountain Shoshonite, Golden, Colorado
Price: US$150 for non-members; US$125 for professional members; US$75 for student members; US$105 for early career professional members
Leader(s): Leah Morgan; Lexie Millikin
Endorser(s): GSA Geochronology Division; GSA Mineralogy, Geochemistry, Petrology, and Volcanology Division; Colorado Scientific Society
CEUs: 0.65
Date(s): Fri., 9 Oct. 2026
Departing Location: Adventure West, Downtown Golden, Colorado, USA (423 10th St Rear, Golden, CO 80401)
Start Time: 9:30 a.m.
End Time: 4 p.m.
Description: Participants will investigate the Table Mountain lava flows by riding e-bikes around Golden, Colorado, and hiking up North Table Mountain.
The Table Mountain lava flows form distinctive geographic features in the foothills of the Rocky Mountains and are classified as shoshonites, which are potassium-rich basalts. We will explore the geology, 40Ar/39Ar geochronology, and geochemistry of these lava flows and associated intrusive units on North Table Mountain. The four main lava flows were extruded across the K–Pg boundary and are interbedded with the conglomeratic Denver Formation, while an intriguing intrusive unit found atop North Table Mountain is nearly 20 Ma younger but compositionally shows only minor differences.
We will also discuss a proposed petrogenetic model for the lava flows, their intrusive source, and their relationship to Laramide tectonism and the Front Range–bounding Golden fault zone. The trip will meet in downtown Golden and will involve under 10 miles of e-biking with approximately 550 ft of elevation change (starting elevation of ~5,700 ft), as well as about 2 miles of hiking with approximately 500 ft of elevation change.
Considerations: Trip participants will meet in downtown Golden, Colorado, at the bike rental shop (Adventure West). This location is accessible from Denver by car, Uber/Lyft, or, with more time, public transit and walking. Helmets are included and required when riding bikes. The trip will involve under 10 miles of e-biking with approximately 550 ft of elevation change (e-bikes include pedal assist, and most also have a throttle). Hiking will include approximately 2 miles with about 500 ft of elevation gain on an established trail (from the North Table Mountain Park West Trailhead to Lichen Peak).
Restrooms are available at the bike rental shop (portable restroom) and at the trailhead, where lunch will be provided. Participants should bring a filled water bottle, which can be refilled at the trailhead. Following the formal portion of the trip, participants may return the bikes directly to the rental shop or optionally stop at a local brewery along the route. The trip will conclude at the rental shop, and participants are responsible for their own transportation after that time.
Cost includes bicycle rental, lunch, snacks, and water.
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.
Learn more about this and other GSA Connects 2026 activities.
For additional information, please contact fieldtrip@geosociety.org.
Product Code: FT26CN407
Product Category: FTRIP
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