Wandering the labyrinths of the spectacular Grand Staircase-Escalante National Monument you may find yourself asking: “what is the Grand Staircase anyway?”
Cliff Arch in Coyote Gulch
A Vast Window to the Past
Simply put, the Grand Staircase is comprised of all rocks from the bottom of the Grand Canyon to the top of Bryce Canyon. This succession of unbroken rock layers displays more of Earth’s geologic history than any other place on the planet!
The Grand Canyon and Canyons of the Escalante slice through the Colorado Plateau, a colossal region covering an area of 130,000 square miles roughly centered on the Four Corners region. Around the time of the formation of the Rocky Mountains the Colorado Plateau was pushed upwards, and miraculously its rock layers remained structurally sound. Most mountain regions are crisscrossed by faults and fractures which results in all types and ages of rocks being placed side by side; a difficult puzzle for geologists to resolve. Meanwhile the rock layers of the Colorado Plateau are displayed in a chronological narrative from the depths of the Grand Canyon (2,400 ft or 740 m) to the lofty heights of Bryce Canyon (10,000 ft or 3,050 m), better known as the Grand Staircase of the Escalante. From nearly 560 million years ago to 45 million years ago the Colorado Plateau existed over a cavernous basin much like the Marianas Trench. The basin was slowly filled by different types of sediments that over lots of time solidified into sedimentary rock by pressure from above. The neatly layered sedimentary rocks helped to anchor the Colorado Plateau during is gradual uplift.
Zoomed in view of the Colorado Plateau with key landmarks. The red line represents what is commonly known as the Grand Staircase Escalante and the rock exposures from the bottom of the Grand Canyon to the top of Bryce Canyon
The forces of Water and time
Exposing the rocks of the Colorado Plateau took the driving force of erosion from the Colorado River, which drains an estimated 246,000 square miles and has an average discharge through the Grand Canyon of 473 billion cubic feet annually. This massive discharge results in a rate of just 1 mm of downcutting per year into the sedimentary rock layers of the Colorado Plateau – about the thickness of a piece of paper.
Cross section of the Grand Staircase of the Escalante
Flat is the equilibrium for all of Earth’s geologic processes. The Colorado River and hundreds of its tributaries are slowly achieving this by cutting away at the rocks and re-stacking them elsewhere. As gravelly washes and creeks turn into deep canyons and slice into the sedimentary rock layers, canyon walls begin to erode from wind, ice, and gravity. This last step reveals the Grand Staircase of the Escalante completely. The varying abilities of different rock layers to resist erosion has created the staircase pattern on the landscape. The Grand Staircase of the Escalante is an erosional feature that has been revealed through millions of years of continuous erosion into the Colorado Plateau. Thankfully, these processes were kind enough to provide hikers with 8 national parks and monuments and more than 14,000 square miles of federally protected land. Wild is waiting on the Colorado Plateau.
Alex Wood – Lead Guide, The Wildland Trekking Company