Fig. 6: Spatial correspondence of geophysical anomalies⁷³, major volcanic fields⁷¹, and incision rates on the Colorado Plateau.

Note that “short-term” incision rates (circles)²⁶ and “long-term” incision rates (triangles) are extrapolated from the same data in some localities and have been the subject of competing interpretations⁷⁵. Dark blue outlines mark locations of the Escalante anomaly and Bidahochi Basin, with the different sizes corresponding to varying estimates of the length-scale of the respective lithospheric drip (see text for discussion). SVF—Springerville Volcanic Field; HBVF—Hopi Buttes Volcanic Field, FL—Fence Lake Formation, and associated late Miocene volcanic rocks. Faults (white lines) represent all mapped faults, regardless of age or type⁷¹. Outline of the area of Fig. 1 is superimposed for reference; note that this boundary excludes regions that may once have been part of the Colorado Plateau but is not considered part of the physiographic Colorado Plateau, including the marginal transition zones and southern Rocky Mountains.