The role played by crustal scale cross-orogen structures in the evolution of orogenic belts is not well understood. The Late Paleozoic-Early Mesozoic New England Fold Belt extends for some 2000km along the eastern Australian continental margin. It originated as an assemblage of convergent forearc terranes in the mid- Paleozoic, underwent widespread extension through the Late Paleozoic, and its history culminated in a major contractional event in the Late Permian-Middle Triassic forming a thin skinned fold thrust belt. The northern end of the fold belt terminates in an oblique shear, the Stanage Fault Zone (SFZ), with 50+ km of dextral strike slip offset. Associated with this shear is an oroclinal bend in the fold-thrust belt through 90 degrees with a half wavelength of ~50 km. The SFZ was active for at least 20 m.y., terminating older, in-sequence, foreland propagated thrusts as well as younger out-of-sequence thrusts. Permo-Triassic granitoids, broadly coeval with the contractional event and with arc trace element signatures, intrude the core of the oroclinal fold. Such granitoids do not appear to the north of the fault zone.

We believe that the contractional event is coupled to the progressive onshore re-establishment of the magmatic arc and that the SFZ is a crustal scale tear fault that not only partitions the upper crustal response, but also constrains the geometry of the subducting slab. Similar potential cross-orogen structures occur approximately 500 km both to the north and south.