The Colorado Plateau's canyons, mesas, plateaus, and mountains expose rock spanning over 2 billion years of geologic time.
The most ancient rocks formed during the Precambrian. These ancient rocks are exposed only in the deepest canyons of the Colorado Plateau's canyonlands, and make up the Precambrian basement of the region. Most of this basement is composed of metamorphic rock that formed deep within the Earth's crust during numerous continental collisions, forming the nucleus of the North American continent. Millions of years later, igneous rocks were injected into this metamorphic complex, resulting in the familiar marbled look seen today in the dark metamorphic basement exposed in the deepest canyons of the Colorado Plateau. The Precambrian basement rocks were uplifted, exposed, and eroded for hundreds of millions of years. By 600 Ma, the basement rocks of North America had been eroded down to produce a very smooth topographic surface. For 600 million years, younger Phanerozoic layered rocks of the Colorado Plateau were deposited on this crystalline basement rock peneplain.
Throughout the Paleozoic Era, from about 600 Ma to 250 Ma, the Colorado Plateau experienced periodic block fault uplifts and downwarping and was periodically flooded by the transgression of tropical seas. Thick layers of limestone, sandstone, siltstone, and shale accumulated in these shallow marine waters. During periods when the seas retreated, these deposits were exposed to erosion. Stream and aeolian processes redistributed the eroded materials from the highlands the exposed marine rocks and deposited them as stream and aeolian sand dune deposits. A record of these transgressive and regressive sea-level fluctuations is preserved in the Pennsylvanian Hermosa Group and Permian Cutler Group rocks exposed in the Colorado Plateau (blue on geologic map).
Near the end of Permian time, there was major upheaval of the rocks of the Colorado Plateau region as the supercontinent Pangea began to form at about 250 Ma. Marine sedimentation waned and terrestrial (non-marine) deposits began to accumulate. From about 250 Ma to 150 Ma, the terrestrial deposition of Triassic to Jurassic sediments produced great accumulations of aeolian dune sand, arid flood plain, and lacustrine deposits (green on geologic map). The Wingate and Navajo Sandstones record the existence of vast desert ergs with sand dunes rising 10s of feet above the desert floor. The Chinle, Kayenta, and Morrison Formations record the existence of vast arid flood plains and shallow lakes. The periodic encroachment of shallow Triassic and Jurassic seas produced the marine portions of the Moenkopi, Entrada, Carmel, Summerville, and Curtis Formations. Periodically, volcanic mountain ranges to the west of the Colorado Plateau erupted vast amounts of volcanic ash that covered the area.
During Cretaceous time, from about 100 Ma to 80 Ma, vast portions of the Western Interior of the U. S. was flooded by an inland seaway that extended from Mexico, across the Colorado Plateau region, to the Arctic Ocean. The Cretaceous rocks exposed in the Colorado Plateau record the formation and eventual filling of this Western Interior Seaway. The Sevier Orogenic belt developed along the western margin of the Colorado Plateau and thrust faulted Precambrian and Paleozoic materials shed sediment into the Western Interior Seaway from the west. The Upper Cretaceous Mancos Shale and the Mesa Verde Group record the filling of this foreland basin (greens on geologic map).
Although exposed to minor basement block uplifts during the Paleozoic, the Colorado Plateau has remained remarkably stable for most of the past 600 million years. Relatively little faulting and folding has affected this high, thick crustal block. In contrast to this stability, the Colorado Plateau is surrounded by regions that have suffered severe deformation. Mountain building thrust up the Rocky Mountains to the north and east. Tremendous tensional deformation created the Basin and Range Province to the west and south. The Basin and Range Province and the Colorado Plateau share similar geological histories. In the early part of the Cenozoic Era, at about 60 Ma, both regions had elevations of less than 3,000 feet. Beginning about 20 Ma, during the Miocene Epoch both the Basin and Range and Colorado Plateau regions were uplifted as much as 10,000 feet. Great tensional stresses developed in the crust, probably related to changing plate motions far to the west. As the crust stretched, the Basin and Range Province broke up into a multitude of graben valleys and elongate horst block mountains. During this fracturing of the crust to the west, the Colorado Plateau was able to preserve its structural integrity and remained a single tectonic block. Eventually, the great block of Colorado Plateau crust rose a kilometer higher than the Basin and Range Province. 
This period of tensional stress was accompanied by widespread igneous intrusions and volcanic activity that produced many of the volcanic mountain ranges within the Colorado Plateau. The Henry Mountains, Abajo Mountains, La Sal Mountains, and the Marysvale Volcanic Field are the exposed records of this igneous activity. As the Colorado Plateau rose, the streams and rivers responded by cutting ever deeper channels in an effort to maintain their equilibrium stream profiles. The most well-known of these rivers, the Colorado River, began to carve the Grand Canyon less than 6 million years ago.
