THIN-SKINNED THRUSTING IN THE NORTHERN NEW-ENGLAND OROGEN, CENTRAL QUEENSLAND, AUSTRALIA

Regional cross sections of the northern New England Orogen and eastern Bowen Basin in eastern Queensland indicate that the climactic Permian-Triassic deformation involved thin-skinned tectonics with the development of a mountain front represented by a syncline formed by crustal delamination with wedging of a thrust sheet from the east. The thrust sheet is exposed in the Folded Zone of the Bowen Basin and is characterized by upright NNW trending folds in Late Permian sediments. The folds have a chevron to flattened chevron style and formed mainly by flexural slip at about 60% shortening with detachment from an underlying basement of Paleozoic rocks. Farther east the basement is overlain by pervasively cleaved rocks of the Gogango Overfolded Zone in which structures show a consistent westerly vergence. These rocks overlie an inferred passive-roof duplex in the underlying basement. Together, the Folded Zone of the Bowen Basin and the Gogango Overfolded Zone constitute a foreland fold-thrust zone with a shortening of 50-90 km. This implies that the New England Orogen has been thrust west along a major east dipping detachment.