Early and middle Cenozoic drainage and erosion in west-central Arizona

摘要: Latest Oligocene time (∼25 m.y. ago) is established as a minimum age for the regional northeast-flowing drainage system in west-central Arizona that existed prior to formation of Grand Canyon. The amounts erosion and fluvial deposition occurred before eruption oldest dated volcanic rocks suggest Paleocene Eocene span uplift deformation southwestern initiated this pattern. Recent refinements revisions Tertiary stratigraphy Utah indicate from northern ended basins like represented by Claron Formation associated fluviolacustrine sedimentary southern Utah. This period north-to separated Canyon cycle at least 15 block faulting interior basin deposition, followed gradual capture integration existing Colorado River.