On the Rocks Salida to Cañon City Transect Field Trip

Date: August 22 - 23, 2025

Tickets are either currently unavailable or available through a third-party website.

Member Registration

ON THE ROCKS PRESENTS

exploring the Arkansas River's Geologic story: bigHorn sheep canyon between salida and caÑon city

Date: August 22-23

Trip Leader: Tom Karnuta

Trip Coordinators: David Schoderbek

In August, RMAG heads to the scenic Bighorn Sheep Canyon, traversing the spectacular outcrops along the Arkansas River between Salida and Cañon City. Leading the tour is RMAG member Tom Karnuta, a Salida-based consulting geologist. Attendees will examine the region’s fascinating geologic history, covering everything from Pleistocene terraces to some of the oldest Precambrian rocks in Colorado, including the thick exposures of Pennsylvanian basin-filling sediments and the thin preserved lower Paleozoic strata. We plan to lay hands on The Great Unconformity, where Ordovician sediments rest on 1.8 billion year-old basement. If you have ever wondered where the Sangre de Cristo Mountains end and the Mosquito Range begins, or where the Wet Mountains merge into the Front Range, or are keen to see where (and why?) the Arkansas River turns southeast and begins it long trek to join the Mississippi River above Vicksburg, then this is the trip for you! Secure your spot soon—this trip is sure to fill up fast!

Trip Description

Leading this trip through Bighorn Canyon's Spectacular scenery is Tom Karnuta. Tom worked as an engineering geologist for Mountain Engineering and Testing Inc. based out of Saldia for over 20 years. As part of his graduate work at the University of Northern Colorado, Tom described rocks along the highway and also along the Arkansas River, from its headwaters near Leadville through to Cañon City.

Cañon City was platted in 1858 as a commerical center to serve mining operations in South Park, the first building was raised in 1860. In 1862 the first commercial oil well west of the Mississippi River was completed near Cañon City. About twenty years later Salida was founded when the Denver & Rio Grande Railroad reached the location, with narrow gauge rails coming upriver from Texas Creek. Naming the town Salida, Spanish for "exit" the developers believed it commemorated the Arkansas River’s departure from the broad valley above to the narrow canyon below.

A geologic history that spans 1,800 million years is exposed in the canyon of the Arkansas River between Salida and Cañon City. Rocks exposed along this valley present an extensive record of Colorado’s geological history, including Precambrian tectonic events, uplift, subsidence, and sedimentation associated with the Ancestral Rocky Mountains Orogeny, and compressional events of the Laramide Orogeny. Volcanic deposits associated with several calderas of the San Juan Mountains are also exposed along Bighorn Sheep Canyon. Paleozoic and Neogene karst development in the Mississippian Leadville Limestone is also evident. Multiple mines, mills, quarries, charcoal ovens, and lime kilns are also present along the trip route, and our guide is familiar with them all.

Planned Stops:

Stop 0: Murdoch’s parking lot: Discussion, “The Crater” and Tenderfoot Hill (S Mountain) 39 Mile Volcanics
Stop 1: Wellsville: Paleozoic sedimentary rocks, syncline, anticline, thrust fault, cave in feature, mining, limestone kilns, natural arch, travertine. Possible short hike through Paleozoic rocks to observe Ordovician fish scales in the Harding Fm. Pleistocene fluvial terraces
Stop 2: Swissvale: Redbeds, contact between Minturn and Sangre de Cristo Fm. Swissvale Gypsum Member, Tertiary lava flow, Landslide scar that blocked Hwy 50.
Stop 3: Howard: volcanics, red beds, charcoal kilns
Stop 4: Maytag BLM site: Exposure of Precambrian metasediments/relict bedding
Stop 5: Parkdale Recreation Site: Mesozoic sediments, feldspar mill, Echo Park graben.
Stop 6a: Contact between Precambrian and Ordovician rock/hands on
Stop 6b: Harding Formation, fossilized fish plates (Astraspis desiderata)/hands on
Stop 6c: Fremont Formation/hands on

Attendees will also recieve a pdf version of Tom Karnuta's Road and Riverside Geology of the Upper Arkansas Valley Guidebook

Logistics

The fieldtrip will start Friday night with a social/mixer/brief fieldtrip overview in conference room at Hampton Inn & Suites. Snacks and cold beverages, including soda, beer and wine, will be provided. We will assemble at 8 am Saturday in the parking lot of Murdoch’s Hardware for “Stop 0,” and will end at Stop 6, near Cañon City, around 4pm. Some of the stops will involve short hikes on trails (some that are rocky) that gain in elevation, so participants should be in good physical condition and must wear sturdy hiking boots. Elevations range from 7,500 to 8,800 ft, so bring a hat, sunscreen, and a jacket in case of cool weather. Participants are encouraged to carpool to the trip to minimize the number of vehicles; parking is very limited at some of the stops. PLEASE BRING YOUR OWN FOOD & BEVERAGES TO THE FIELD, AS NONE WILL BE PROVIDED.

Lodging

Some registrants are staying at the Hampton Inn in Salida, Co, and the Friday August 22 evening meet up will be at the Hampton Inn.

Additional nearby lodging:

Cost

$80 for members
$100 for non-members. (not a member? click here to join)
Are you a student? email staff@rmag.org

Refunds for the August 22-23, trip are only available until August 11, 2025

If you are unable to attend, your registration for all RMAG events are transferable. RMAG members may transfer their registration to another RMAG member, and non-members can transfer their registrations to whomever they wish. Should an RMAG member wish to transfer their registration to a non-member, the non-member would need to pay the balance between the member and non-member price.

Waivers

All registrants must fill out the Medical Emergency, Waiver and Release of Liability form. Those who fail to complete the form will not be permitted to attend the field trip.

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