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The Needles District in Canyonlands National Park, Utah, is known for its well-exposed array of extensional faults, which are thought to be produced by gravity-driven extension and downward flexure of a thin sandstone plate into the Colorado River canyon in response to dissolution and flow of underlying evaporites (halite and gypsum). Owing to a lack of precise geodetic data, however, it remains uncertain if and to what extent those extensional faults are currently deforming. In this study we use synthetic aperture radar (SAR) data to search for ongoing, decadal ground displacements, by applying both a stacking interferometric SAR (InSAR) analysis and Interferometric Point Target Analysis (IPTA). Our results show...
The salt valleys over the axis of the salt-cored anticlines in the Paradox fold and fault belt (Canyonlands, Utah and Colorado) are created by subsidence of the anticline crests. Traditionally, the collapse of the anticlinal crests was attributed to dissolution of the salt walls (diapirs) forming the anticline cores. Recent studies based on scaled physical models and field observations propose that the salt valleys are a result of regional extension and that salt dissolution had only a minor influence in the development of the axial depressions. This paper presents several arguments and lines of evidence that refute the tectonic model and support the salt dissolution subsidence interpretation. The development of...
The salt valleys over the axis of the salt-cored anticlines in the Paradox fold and fault belt (Canyonlands, Utah and Colorado) are created by subsidence of the anticline crests. Traditionally, the collapse of the anticlinal crests was attributed to dissolution of the salt walls (diapirs) forming the anticline cores. Recent studies based on scaled physical models and field observations propose that the salt valleys are a result of regional extension and that salt dissolution had only a minor influence in the development of the axial depressions. This paper presents several arguments and lines of evidence that refute the tectonic model and support the salt dissolution subsidence interpretation. The development of...
The Needles District in Canyonlands National Park, Utah, is known for its well-exposed array of extensional faults, which are thought to be produced by gravity-driven extension and downward flexure of a thin sandstone plate into the Colorado River canyon in response to dissolution and flow of underlying evaporites (halite and gypsum). Owing to a lack of precise geodetic data, however, it remains uncertain if and to what extent those extensional faults are currently deforming. In this study we use synthetic aperture radar (SAR) data to search for ongoing, decadal ground displacements, by applying both a stacking interferometric SAR (InSAR) analysis and Interferometric Point Target Analysis (IPTA). Our results show...
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Grabens in Canyonlands National Park, Utah, began extending above a layer of evaporites when the Colorado River cut through the overburden. Two-dimensional finite element models simulate the effects of geometry and rock properties on graben configuration and spacing. Only those models having a progressively increasing slope or no slope mimicked the natural upslope graben propagation. Typical rock properties produced the most realistic fault patterns: an initial friction angle of 31°, a cohesion of 1 MPa, and strain weakening comprising cohesion loss and decrease of friction angle to 26°. A tensile stress limit narrowed the grabens and reproduced the vertical upper portion of the natural faults. The viscous salt...
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Results of numerical models and field observations of regularly spaced grabens in Canyonlands National Park, Utah, demonstrate that salt flow beneath a brittle overburden accommodated recent and ongoing westward gravity spreading. Erosion of the Colorado River canyon differentially loaded the underlying viscous salt. In our models, the overlying brittle strata flexed downward toward the canyon, initiating faults near the surface that propagated downward toward the salt contact. Modeled grabens developed sequentially away from the canyon (eastward) as salt was expelled from beneath undeformed strata. After their eastern boundary faults broke through, horst blocks tilted in the opposite direction of initial flexure,...
Results of numerical models and field observations of regularly spaced grabens in Canyonlands National Park, Utah, demonstrate that salt flow beneath a brittle overburden accommodated recent and ongoing westward gravity spreading. Erosion of the Colorado River canyon differentially loaded the underlying viscous salt. In our models, the overlying brittle strata flexed downward toward the canyon, initiating faults near the surface that propagated downward toward the salt contact. Modeled grabens developed sequentially away from the canyon (eastward) as salt was expelled from beneath undeformed strata. After their eastern boundary faults broke through, horst blocks tilted in the opposite direction of initial flexure,...
    map background search result map search result map Mechanics of graben evolution in Canyonlands National Park, Utah Modeling of grabens extending above evaporites in Canyonlands National Park, Utah Mechanics of graben evolution in Canyonlands National Park, Utah Modeling of grabens extending above evaporites in Canyonlands National Park, Utah