Running 277 miles in length, the Grand Canyon has a geologic history that extends two billion years, when a pair of plates on the earth’s crust collided. This led to the formation of metamorphic and igneous rocks, under intense heat and pressure, and these presently make up its inner gorge. Among this these dark-hued “basement” rocks is the Elves Chasm gneiss, which represents the oldest rock discovered in the canyon at 1.84-billion-years-old.

Above this foundational layer, thousands of layers of sedimentary rock built up over the millennia, each representing a distinct environmental context within the narrative an evolving planet. Prehistoric seas deposited sediments that ultimately hardened and formed the rock of each layer.

Between 30 to 70 million years ago, the entire region experienced uplift, which created an elevated, relatively flat Colorado Plateau. From this point, the Colorado River carved its way steadily inward. Tributary streams contributed to a widening out of the canyon, in a process of weathering and expansion that continues to this day.