We’ve been wanting to put together a calendar for some time now, and 2023 seems to be the right year! The geology of Colorado and its landscapes are as varied and as colorful as any place on the planet. And, yes, we think this collection of images from our staff—with jobs that often include field research—does a great job showing off our favorite state! We plan to make this an annual project. You can order your calendar on our (new) Amazon publications store. The contest is over: after a huge response, we’ll be contacting folks in the next couple days to let them know their status! Pawnee Buttes in the Pawnee National Grasslands are capped with a cemented sand-silt-conglomerate from the Miocene Ogallala Group underlain with tuffaceous sandy silts from the Eocene-Oligocene White River Formation. Photo credit: Colorado Geological Survey. These tuffs in the Wheeler Geologic Area near Creede, Colorado show varying degrees of welding. The light slopes are not very welded and thus are highly erodible. The darker rocks are more densely welded and thus resist erosion, protecting the softer tuffs below. The tuffs erupted during the formation of the San Luis caldera. Photo credit: Vince Matthews for the CGS. Centennial Arch in Rattlesnake Canyon, Mesa County, along the Colorado-Utah border, spans 40 ft (12 m) along the canyon wall of Entrada Sandstone, remnants of a vast dunefield that has been preserved in stone since the Jurassic. Photo credit: Matt Morgan. The dunes from the park entrance road in spectacular clear air after an overnight dusting of snow at Great Sand Dunes National Park. Mount Herard (13,345 ft/4068 m) is the highest peak. Photo credit: Vince Matthews. Steamboat Rock, along the Green River in Echo Park, Dinosaur National Monument, Colorado. Photo credit: John Hopkins. Remnants of the Eagle Mine at Belden along the Eagle River. The town, barely visible 600 feet above, is the abandoned town of Gilman where its residents would ride a tram down to the workings below. Photo credit: Larry Scott. The rugged Elk Tooth (12,848 ft / 3916 m) in the Indian Peaks Wilderness surrounds the smaller Saint Vrain glaciers which form the headwaters of the Saint Vrain River in northern Boulder County. Photo credit: Kyren Bogolub. A few of the images from CGS staff that are included in the calendar.