Inversion (geology)

The term negative inversion is also occasionally used to describe the reactivation of reverse faults and thrusts during extension.

The term "inversion" simply refers to the fact that a relatively low-lying area is uplifted – the rock sequence itself is not normally inverted.

The existing fault block still generally acts as a boundary to the uplift and the process is sometimes known as buttressing.

Lower angle faults are more favourable as the resolved shear stress on the plane is higher.

The nature of inversion means that reservoir units often thicken and may increase in quality within the basin that is later inverted (e.g. the Ormen Lange gas field offshore mid-Norway).

Section across southern England showing the inverted nature of the Channel and Weald basins
The Quantocks Head Fault, west of Kilve , Somerset , showing the effects of inversion on the earlier normal fault, with folding and thrusting in the hanging wall