[1] In the early Proterozoic, between 1.78 and 1.65 billion years ago, the continental crust of Colorado was assembled from several older island arcs, along the coast of the Archean Wyoming Craton.
These deep extensional basement faults filled with sediments, such as the Uinta rift basin and were often reactivated more recently in Earth history by orogenies.
The end of the Neoproterozoic is not known from the rock record, indicating a period of long-running terrestrial erosion which produced by the Great Unconformity, from 1.1 billion to 510 million years ago.
The Sonoma orogeny uplifted the ancestral Rocky Mountains around 300 million years ago, which reached heights of around 10,000 feet.
Dark red Triassic shale and wind-blown sands transformed into sandstone overlie Permian rocks, marking the beginning of the Mesozoic.
Early Jurassic dune sands were covered over by the sandstone and shale of the Morrison Formation, until a large scale marine transgression flooded the region in the Cretaceous.
With the beginning of the Laramide orogeny that uplifted the Rocky Mountains, coastal wetlands formed large coal deposits.
Together with Utah and Nevada, Farallon Plate related volcanism in the Oligocene produced enormous eruptions that built up the San Juan Mountains in the southwest.
Throughout the Miocene, large scale regional uplift elevated Colorado, New Mexico, Utah and Arizona 5000 feet above sea level.