Upheaval dome is a breached domal structure that is surrounded by a well-developed rim syncline; it is in the rugged canyon lands of southern Utah, near the western margin of the Para dox basin. Strata that range in age from Permian to Jurassic are exposed in the dome, and all have been deformed by the forces which produced the feature. About 3,000 ft of Pennsylvanian salt beds underlies the area of the dome. The origin of Upheaval dome has not been established, but the following hypotheses have been advanced: (1) it is a cryptovolcanic feature; (2) it is a simple salt dome; (3) it was formed by meteorite impact; (4) unloading of overburden through stream erosion resulted in the upward migration of the salt; and (5) it is a salt dome produced by multiple salt movements resulting from local diastrophism and igneous intrusion. The writer suggests that the dome is the product of salt flowage resulting from differential pressures which were produced by differential compaction of the sediments over the flanks of a buried hill, or monadnock, on the Precambrian basement complex.
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Diapirism and Diapirs: a symposium
“Diapir” and “diapirism” come from the Greek diapeirein, which means “to pierce.” Diapirism sensu lato is a process by which earth materials from deeper levels have pierced, or appear to have pierced, shallower materials; it is divided into magmatic intrusion and diapirism sensu stricto on the basis of the temperature at which piercement occurs. Diapirs s.s. are composed of evaporites, argillaceous sediments, coal, peat, ice, serpentine, or other earth materials which have the critical characteristics of low equivalent viscosity and low density. These materials range in age from Precambrian to Recent. Diapirs are found in all parts of the world except the shield areas. They have many forms, ranging from smoothly rounded pillows to complexly injected laminae, are either connected with or disconnected from the “mother” bed, and are present either at the surface, where they form distinctive features, or at considerable depth. Diapirs have well-developed internal structures indicative of an origin by flow. Strata around a diapir may be strongly affected structurally and/or stratigraphically by the diapir, or they may be unaffected. Field and model studies indicate that diapirs have developed as a result of horizontal compression, gravitational instability, or both. Diapiric structures of various types contain large quantities of oil and gas, sulfur, salt, and potash and are important for underground storage and nuclear testing.