Magellan
A forward marine magnetic modeling program

Ridge Jump

In Magellan the term 'ridge jump' is often used. It is caused by a propagating rift, which is demonstrated in a map view in Figure 1. In a ridge-transform-ridge system one of the ridges can start propagating, replacing the other ridge (dying ridge, DR). The propagating rift (PR) transfers lithosphere from one plate to the other, in Figure 1 lithosphere is being transferred from plate B to plate A (so that lithosphere that used to be on plate B is transferred to plate A).

Fig 1. Map view of a propagating rift. The propagating rift (PR) transfers lithosphere from plate B to plate A when it takes over the dying ridge (DR). The zone of transferred lithosphere (ZTL) is what is added and removed. The two pseudofaults (PF) are the same age and the failed rift (FR) is the rift that once was active. The vertical lines represent isochrons.

In a crossesction perpendicular to the strike of the ridge this process appears as an instantaneous ridge jump. There are two pseudofaults (PF) and one failed rift (FR) associated with a propagator. These features can be seen in Figure 1. The pseudofaults are always the same age and cause a rupture in the magnetic anomaly signature which could be interpreted as a fault, hence the name pseudofault.

In Magellan, the two parameters describing the ridge jump are the time of jump and the distance of jump. The time of jump represents the time at which the propagator hits the profile over the ridge (in myr), making it look like the ridge is actually jumping in the profile. The distance of jump is the distance from the DR to the PR along the profile perpendicular to the strike of the ridge