People | George
Davis
Stress-Strain and Colorado Plateau Uplifts
Late Cretaceous-Early Tertiary Laramide Deformation
of the Northern Colorado Plateau, Utah and Colorado
The structure of the northern Colorado Plateau
is dominated by a series of highly asymmetrical, presumably fault-cored
anticlines: the
Kaibab, Circle Cliffs, Miners Mountain, San Rafael Swell, Monument,
and Uncompahgre uplifts. In map view, they are irregularly distributed
with widely varying sizes and orientations. In Permian through
Jurassic rocks, interpretations of outcrop-scale structures, including
jointed Eshelby inclusions, stylolites, en echelon vein arrays, deformation
bands, and meso-scale faults, show principal stress directions that
are consistently oriented within each uplift, but vary considerably
between uplifts. In general, the results indicate that there
are two groups of uplifts, one of which shows evidence of NE-SW-directed
compressive stress, and another which shows evidence of NW-SE contraction. Because
deformation in the sedimentary cover is forced by differential movement
of basement fault blocks, cover stress patterns may be interpreted
as basement strain patterns. These results are similar to the
kinematic interpretations of Kelley and Clinton (1960) and highlight
the importance of oblique slip. Finally, examination
of structural contours allows the interpretation of basement strain
magnitudes and indicates that the major faults are not interconnected.
[Bump, A.P., and Davis, G.H., 2003, Late Cretaceous
to early Tertiary Laramide
deformation of the northern Colorado Plateau, Utah and Colorado:
Journal of Structural Geology, v. 25, p. 421-440.]
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