A review of the regional geophysics of the Arizona Transition Zone
Article first published online: 20 SEP 2012
Copyright 1991 by the American Geophysical Union.
Journal of Geophysical Research: Solid Earth (1978–2012)
Volume 96, Issue B7, pages 12351–12373, 10 July 1991
How to Cite
1991), A review of the regional geophysics of the Arizona Transition Zone, J. Geophys. Res., 96(B7), 12351–12373, doi:10.1029/90JB01781., and (
- Issue published online: 20 SEP 2012
- Article first published online: 20 SEP 2012
- Manuscript Accepted: 18 JUL 1990
- Manuscript Received: 14 MAR 1989
A review of existing geophysical information and new data presented in this special section indicate that major changes in crustal properties between the Basin and Range and Colorado Plateau occur in, or directly adjacent to, the region defined as the Arizona Transition Zone. Although this region was designated on a physiographic basis, studies indicate that it is also the geophysical transition between adjoining provinces. The Transition Zone displays anomalous crustal and upper mantle seismic properties, shallow Curie isotherms, high heat flow, and steep down-to-the-plateau Bouguer gravity gradients. Seismic and gravity studies suggest that the change in crustal thickness, from thin crust in the Basin and Range to thick crust in the Colorado Plateau, may occur as a series of steps rather than a planar surface. Anomalous P wave velocities, high heat flow, shallow Curie isotherms, and results of gravity modeling suggest that the upper mantle is heterogeneous in this region. A relatively shallow asthenosphere beneath the Basin and Range and Transition Zone contrasted with a thick lithosphere beneath the Colorado Plateau would be one explanation that would satisfy these geophysical observations.