Mechanics of active salt diapirism

摘要: Abstract An active diapir forcefully intrudes its overburden, driven by pressure that overcomes the resistance of overburden strength. Possible causes for driving are differential loading source layer and a density contrast with overburden. resisting forces derive from mass roof block to faulting folding accommodate intrusion. For typical between salt sedimentary simple force balance demonstrates height must be more than two-thirds three-quarters thickness surrounding initiate substantial diapirism. Narrow diapirs even taller. Physical numerical modeling show structures diapirism central crestal graben flanked relatively unstrained flaps rotate upward outward. Curved reverse faults can separate regional Normal in propagate downward, new created farther outward as arches over rising diapir. Thin, wide roofs develop multiple grabens separating flat rotating flaps. In cases leading emergence, piercing evolves pointed crest progressively rounded widening The models flexure contributes early formation structures, but piercement does not continue emergence unless is very or tall relative thickness. Active becomes difficult crests ranging rectangle, round-cornered semicircle, triangle crest.