Fractured late Paleozoic and Mesozoic strata at the southern edge of the Holbrook basin in east-central Arizona overlie an active salt-dissolution front. Where the evaporates have been dissolved, the overlying strata have been offset by approximately 100 m, creating a draped monocline called the Holbrook Anticline. This dissolution-front monocline extends along a northwesterly trend for more than 100 km. Strata immediately over the dissolution front have been stretched by bending during migration of the front. The regional fractures that were present in these strata have been reactivated in extension, and some of the fractures at the crest of the anticline now have "apertures 1, up to several meters wide. Large wedges of rock between fractures are locally displaced downward as much as 15 ml forming small grabens. Many of these grabens were enlarged to form sink holes hundreds of meters across that are filled with talus breccia that formed from collapse of the overlying strata. Buckling of the surficial strata is also present in localized compressional zones associated with bending at the toe of the anticline and elsewhere. This suite of features comprises a model that can help to refine interpretations of the reservoir characteristics of fractured oil and gas fields associated with similar, deeper, dissolution fronts, such as the Silo field in Southeastern Wyoming.
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