Limestone speleothems (var. stalactite) hang from the ceiling of Glenwood Caverns, Glenwood Springs, Colorado. Photo credit: Vince Matthews for the CGS.

115th Annual AASG Meeting, Glenwood Springs, Colorado

2023-03-01 | CGS Admin

The 2023 Association of American State Geologists meeting—hosted by the Colorado Geological Survey—takes place in Glenwood Springs, Colorado, between June 11-15. The meeting is open to AASG members and its associates, as well as various government and scientific agencies.


For questions or more information on the meeting and registration, please email Matthew Morgan, Director and Colorado State Geologist.




Full Meeting Registration $695 :: Honorary Members or Guests $400 :: Single Day Registration $300 :: Pre-Meeting Field Trip $175 :: Post-meeting Trip $175 :: Mid-Meeting trip included in full registration fee :: Guest Field trips on June 12 & 14 $120 :: Post-Field Trip Dinner $92 :: Room rate $189/night

LODGING (and tax exemption) ::

Lodging is at the classic Hotel Colorado :: Attendees may book any room type available at a special $189/night rate.

The Hotel Colorado, Glenwood Springs, Colorado.
The Hotel Colorado, Glenwood Springs, Colorado.

IMPORTANT NOTE :: If attendees are expecting a tax exemption, they will need to fill out these two forms and email them to or fax them to 970-945-7030 after they make their guest room reservation. The tax will be removed from their bill upon receipt of the forms. 

PRE-MEETING FIELD TRIP, June 11 [$175] :: Late Cenozoic Evolution of the Colorado River: evidence for Neogene uplift, climate change and drainage integration

Led by Andres Aslan

Rafting on the Colorado River below an exposure of the Great Unconformity, in Glenwood Canyon, alongside an elevated section of Interstate-70. Photo credit: Vince Matthews for the CGS.

The Colorado River system, as the single river system that drains the western slope of the Colorado Rocky Mountains, is a sensitive gauge of the uplift history and landscape evolution of the western U.S. This trip focuses on the Upper Colorado River basin and evaluates the hypothesis that the river system and modern Colorado Rockies are being shaped by neotectonic epeirogenic uplift of the Colorado Rockies, interacting with climatic and geomorphic forcings. The view presented here is that this epeirogenic uplift is primarily related to mantle buoyancy.

Trip stops will include the 1) Carbondale area to view the remnants of the late Miocene paleo-land surface that records the start of regional denudation, 2) Dotsero area to view the Yellowstone Lava Creek B tephra associated with ca. 640 ka ancestral Colorado River gravels. This stop involves a short hike with about 350 ft of elevation gain, 3) Glenwood Canyon to discuss the canyon’s incision history, and the 4) Rifle area to examine Quaternary Colorado River terraces and debris-fan complexes that record river incision over the past ~2 Ma. This last stop also involves a short hike with about 350 ft of elevation gain.

MID-MEETING FIELD TRIP, June 13 [included with full registration fee] :: Glenwood Springs to Aspen: Geologic Hazards in the Roaring Fork Valley (lunch included)

Led by Jill Carlson, Jonathan Lovekin, and Karen Berry

A large sinkhole opened in January 2005 at the Ironbridge Development and Golf Course, in the Roaring Fork River Valley, approx. 6 mi. (9.7 km) southeast of Glenwood Springs. Two golf carts inside the structure were lost down the throat of the sinkhole. View is to the northeast. The red cliffs in the background are the Maroon Formation. For scale, note person in white hardhat standing in the snow. Photo credit: Jon White for the CGS.

This field trip will focus on geologic hazards in the rapidly developing Roaring Fork Valley. Hazards in this region of Colorado include: evaporite dissolution- and historic coal mining-related subsidence, coal fires, debris flows, landslides, rockfall, and avalanches. We will see examples of many of these hazards along with examples of hazard mitigation.


Following the mid-meeting field trip, join your colleagues for a fantastic dinner at the Hotel Colorado Restaurant and Bar. You’ll have plenty of time to sit back, relax, and discuss the day’s events and exciting geology of the area. Following dinner, you may either stay at the restaurant bar or enjoy libations in the adjacent Copper Top Bar and Lounge. Please select your general entrée choice from the registration page – salad, dessert, soft drinks and coffee/tea + tax/tip are included.

POST-MEETING FIELD TRIP, June 15 [$175] :: Geologic potpourri of the southwest corner of the White River Uplift (WRU)

Led by Vince Matthews, Jonathan White, and Peter Barkmann

Along the Grand Hogback. Photo credit: Vince Matthews for the CGS.

Outstanding exposures in this area display evidence of Laramide and Ancestral Rocky Mountains tectonism as well as present-day evaporite tectonics and dissolution. A visit to the travertine cliffs and caves at Rifle Falls State Park provides excellent views of the Grand Hogback monocline that overlies a 20,000-foot fault displacing the energy-rich (natural gas and oil shale) Piceance Basin from the WRU and exposes consequences of underground coal fires—some still burning. The effects of ongoing evaporite tectonism and dissolution are nicely displayed and bound a field of mid-Cenozoic laccoliths. Neogene and Quaternary volcanism provides age control on the regional collapse center and incision of Glenwood Canyon by the Colorado River.


The famous Maroon Bells, southwest of Aspen, Colorado, are composed of Maroon Formation mudstone. Photo credit: Vince Matthews for the CGS.
The Maroon Bells, southwest of Aspen, Colorado, are composed of Maroon Formation mudstone. Photo credit: Vince Matthews for the CGS.

June 12, 10:00 am – 4:00 pm [$120]: Redstone and Aspen, with an optional shuttle trip to view the iconic Maroon Bells (lunch included).

Limestone speleothems (var. stalactite) hang from the ceiling of Glenwood Caverns, Glenwood Springs, Colorado. Photo credit: Vince Matthews for the CGS.
Limestone speleothems (var. stalactite) hang from the ceiling of Glenwood Caverns, Glenwood Springs, Colorado. Photo credit: Vince Matthews for the CGS.

June 14, 10:00 am – 4:00 pm [$120]: Glenwood Caverns Adventure Park — Two cave tours and thrill rides in a mountain-top setting (lunch included).

Aerial view of Glenwood Springs, with the Colorado River on the left, and the Roaring Fork River to the right.

Glenwood Springs, the historical resort town located at the confluence of the Roaring Fork and the Colorado rivers at the west end of Glenwood Canyon, is surrounded by the Rocky Mountains of central Colorado. Not far from Aspen, the area features several hot springs, a wide range of geological and natural features, along with plenty of great summertime recreational activities in and around town.


The altitude at Glenwood is 5,761 ft. and pretty much everywhere surrounding is higher! If you are coming from lower elevations, take your time to let your body adjust. The symptoms of altitude sickness include headaches, dizziness, diminished appetite, nausea, fatigue, and insomnia.

Afternoon highs are in the upper 70s/low 80s F; nights are cool, into the mid-40s F; short but intense afternoon thunderstorms are common in the region; and there are significantly variable micro-climates whether on the river, in sun/shade, and when at higher altitudes in the area.

As is typical in the US west, humidity is low, and hydration is important: carry water and remember to hydrate! It’s best to have three or four layers of clothing to adjust to 30-degree temperature fluctuations. Fleece works well combined with a wind/rain shell and good hiking shoes for exploring. Solar radiation can be intense: hats, sunglasses, and sunscreen are a must. Be sure to bring a swim suit to enjoy a soak in the hot springs!

Official Colorado visitor information :: Colorado Trail Explorer (CoTREX) :: Current weather in Glenwood


Nearest Airports: Eagle/Vail is 30 miles east, Aspen is 40 miles south, Grand Junction is 90 miles west, and Denver International Airport is 180 miles east of Glenwood Springs.

Rental Car Companies: Most major car rental companies (e.g., Alamo, Enterprise, Hertz, Avis, Budget) are available at the airports and near major cities, including Glenwood Springs.

Taxi Service: Lyft and Uber operate in the area as well as High Mountain Taxi service.

Colorado Department of Transportation (CDOT) travel/road information


To be included as an 2023 AASG Glenwood Springs meeting sponsor, please download and submit our 2023 sponsorship level form to Matthew Morgan.

CSS logo