Geophysical testing of balanced cross-sections of fold-thrust belts with potential field data: an example from the Fleurieu Arc of the Delamerian Orogen, South Australia

We present magnetic forward models for two balanced cross-sections of the Fleurieu Arc in the Delamerian Orogen. The forward models require a larger volume of magnetic basement at shallower depths than predicted by balanced sections, requiring a revision of currently proposed shortening mechanisms. The shortening mechanism inferred from the models requires less imbrication of upper crustal units, and more folding above thrusts that involve both basement and cover sequences. This style of shortening compares favorably with published observations from the Ross Orogen in Antarctica.