Why can the present position of a salt dome differ from the location of earlier uplifted rock layers?

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salt dome Figure 1: Interrelationships of salt structures (see text)

The present position of a salt dome may differ from the location of earlier uplifted rock layers because of late-stage movement of the salt mass. This offset relationship indicates that the center of the salt dome shifted during a subsequent phase of uplift compared to where the initial deformation occurred.1

As salt is a relatively plastic material, it can flow over long periods due to gravitational or tectonic forces, causing the salt core to migrate or pierce through sedimentary strata. While the salt typically domes the overlying strata as it rises, the dynamic nature of this upward growth means the structural center of the salt mass does not always remain perfectly aligned with the original site of the uplifted rock.231