Oroclines in the Tasmanides

In contrast to the other orogens, consensus that at least part of the curvature in the Palaeozoic to Triassic New England Orogen is oroclinal has been broad, although not universal. There remains substantial debate over the number of hinges (from two to four) and mechanism. Palaeomagnetic poles have previously been cited as evidence of rotation of blocks within the orocline, but this paper presents the first formal palaeomagnetic orocline test, which is positive for the Manning and Texas hinges. A palaeocurrent orocline test of the Manning hinge, in younger rocks than the palaeomagnetic sample, is negative, constraining rotation in the southern, Manning hinge to the Carboniferous before 322 Ma, while rotation in the northern, Texas hinge appears to be latest Carboniferous or Permian. The existence of a Hastings hinge is questionable, but if real, its rotation also appears to be younger than that of the Manning hinge. Thick-skinned, secondary rotation of the hinges of the New England orocline appears to have been diachronous.