Using small-scale structures as a tool for understanding regional deformation: A study of deformation bands and faults at Kettleman Hills, California

This study focuses on the character of deformation bands and outcrop-scale faults at the Kettleman Hills anticline in south-central California. At Kettleman Hills, all deformation bands and most small-scale faults strike either ~340 degrees and dip 60-80 degrees to the NE or SW, or strike ~200 degrees and dip 60-80 degrees to the NW and SE, resulting in multiple pairs of conjugate sets. Unrotation to pre-folding orientations reveals that the structures formed during or after folding of Kettleman Hills, and spatial variation analysis in deformation band and fault orientations suggests that the structures reflect regional rather than local deformation caused by folding. The orientation of deformation bands and outcrop-scale faults at Kettleman Hills best fit the geometry of Riedel shear, an observation corroborated by evidence on the regional scale. These findings suggest that small-scale structures on folds can be useful for understanding the character of regional deformation. Specifically, this study highlights the value of using small-scale structures such as deformation bands and faults to improve understanding of deformation of the San Andreas fault borderlands