Paleomagnetic determination of vertical-axis rotations within the Charleston-Nebo salient, Utah

The Charleston-Nebo salient is highly convex toward the foreland of the Sevier fold-thrust belt in Utah. To determine the importance of vertical-axis rotations to the kinematic history of the salient, paleomagnetic samples were collected from red Triassic strata of the Woodside Shale and Ankareh Formation from 68 sites distributed around the curvature of the salient. The paleomagnetic data indicate counterclockwise rotation of 33.3degrees +/- 4.8degrees in the northern part of the salient and clockwise rotation of 66.7degrees +/- 5.1degrees in the southern part of the salient. These data support divergent-now models for thrust-salient development, augmented by relatively minor contributions from original basin geometry and local strike-slip along salient margins.