Preliminary Geophysical Framework of the Upper and Middle Verde River Watershed, Yavapai County, Arizona

Magnetic and gravity data also delineate exposed and concealed faults within the study area. The Big Chino fault and Verde fault zone have the largest amounts of vertical throw of any fault in the study area based on gravity, magnetic, and limited well data. These faults bound deep (1-2 km) basins in Big Chino and Verde Valleys.

The geophysical data also reveal concealed faults in Williamson Valley that bound a previously undiscovered basin with approximately 1 km of Cenozoic fill inferred from inversion of gravity data. Little Chino and Lonesome Valleys, including the upper reach of the Agua Fria basin, are characterized by basin fill which nowhere exceeds 1 km and has a more irregular distribution with local, north- to northwest-striking pockets of thicker sediment.

A 15- to 20-km-long northwest-striking magnetic lineament that passes through Page Springs in Verde Valley can be used to project a fault 5-10 km northwest and southeast of its mapped trace. The colocation of the lineament, mapped fault, and the spring suggests structural influence on the location of this large spring. [Summary provided by the USGS.]