lowerbeaver_paleo.html


Paleogeography of Central Arizona during deposition of lower unit of Beavertail Conglomerate and related deposits.

The Transition Zone and Colorado Plateau were probably of coequal elevation but a broad strike valley bounded by the Kaibab escarpment to the NE and the mountains of the Transition Zone to the SW separated the two provinces. For such a valley to form, there must have been a much lower base level to the SE that tapped the streams in central Arizona. An enormous amount of sediment must have been removed from central Arizona in order to have formed the strike valley. Several streams carved canyons northward perpendicular to the evolving Mogollon Rim. The largest of these lay 20 km SE of Sedona. Local Rim-derived sediment preserved in these canyons (700-1000 m deep) mark the oldest deposits of the Beavertail Conglomerate. These events are likely coeval with Oligocene latite volcanism (30-23 Ma) in the western and southern portions of the region. The low cusestas and hogbacks north and east of Sedona mark the location of Laramide folding and faulting (Holm and Cloud, 1990). Towns: F - Flagstaff, S - Sedona, C - Cottonwood, CV - Camp Verde, Ch - Chino Valley, P - Prescott