Armchair Adventures
America’s public lands offer some of the most spectacular and interesting places you’ll ever see. While everyone is encouraged to stay at home, the BLM Blog will feature "Armchair Adventures." This is your opportunity to travel virtually and learn a bit about these amazing places. Today, follow along with the sixth installment of Armchair Adventures.
Collared Lizard, Colorado
A male common collared lizard poses on a rock in Big Dominguez Canyon. Collared lizards are named for two black bands at the base of their necks that look like collars (only one band is visible in this image). Males are very brightly colored and can grow to 14 inches long. They can adjust color somewhat depending on surroundings and are brightest during mating season. Collared lizards have a very wide range extending from the Ozarks to west to California. They run on their hind legs and are very fast being clocked up to 16 mph. Collared lizards are called “mountain boomers” in Oklahoma and surrounding areas. Various theories surround this name, which is especially curious since collared lizards make no sounds. Collard lizards eat mostly insects and other lizards . . . including other collared lizards! They lay up to 12 soft leathery eggs and hatchlings are immediately on their own with no care from their parents.
Rattlesnake Arch, McInnis Canyons, Colorado
Rattlesnake Arch with its 40-foot span stretching above a 120-foot high window is the namesake of this collection of 35 natural arches in the backcountry of McInnis Canyons National Conservation Area, just outside of Grand Junction, Colorado. The area includes the world’s second largest concentration of arches outside of Utah’s Arches National Park.
Arches here and elsewhere in the Colorado Plateau region are found mostly in the Entrada sandstone layer, which has very porous structure and grain pattern that lends itself to their formation. The smooth, salmon-colored sandstone was deposited more than 175 million years ago in the form of sand dunes on an ancient coastline. After the ancient inland sea disappeared, erosion started sculpting contoured alcoves into cliff walls with wind-blown grit, frost wedging, and quick runoff thinning out the alcoves until holes appeared. Water puddles in the Entrada just above a denser layer called the Carmel formation, where it erodes like a cavity prying the rock apart from underneath. Erosion is a constant process and current arches will eventually collapse while holes will emerge in current alcoves turning them into arches.
Big Jacks Creek, Idaho
The gently sloping sage covered Owyhee Uplands are located in a very remote region two hours south of Boise. They have a geologic history that was much more violent than their sublime appearance suggests. The uplands hide a number of dramatic canyons including this deeply eroded cleft formed by Jacks Creek. These canyons provide a window into layers of rock that are evidence of the area’s ancient volcanic activity. As the North American Tectonic Plate moved westward, the stationary Yellowstone Hotspot created a series of giant calderas beginning in eastern OR and NV. Currently Yellowstone National Park moved sits over this thin area of the earths crust. The hotspot was under the Jacks Creek area around 12 million years ago. Periods of repeated volcanism during this time deposited the layers of red-brown ryolite rock visible on the canyon walls. Softer layers of unconsolidated ash make up the vegetated layers between the harder ryolite. The unique chemical composition of eruptions from this area known as the Bruneau-Jarbidge volcanic field have been traced to ash deposits that caused the deaths of animals and preserved their fossilized remains more than 1,000 miles east in Nebraska.
Big Jacks Creek is a far quieter place in the present. The canyon and surrounding uplands conserve a rich array of great basin plant and animal communities. California bighorn sheep seek refuge from predators by navigating the steep canyon cliffs while redband trout find cool shade from the intense desert sun in narrow willow-lined streambed.
