Large‐scale horizontal displacements in Southern Australia — Contrary evidence from Palaeomagnetism

Palaeomagnetic results from 40 dykes sampled on Eyre Peninsula and Yorke Peninsula, South Australia, are inconsistent with the clockwise rotation of the ‘foot’ of Yorke Peninsula by fault‐drag during the Early Ordovician. A reinterpretation of earlier data from Tasmania also indicates that the east‐west structural trends in the Mount Reed volcanic arc and Dundas Trough are primary. The effects of shearing were probably restricted to linear displacements without causing rotation of adjacent structural elements. Late Precambrian and Cambrian palaeomagnetic data from Fleurieu Peninsula and Kangaroo Island have also been analysed. They do not clarify the pattern of structural evolution in the southern part of the Adelaide Orogen because the magnetic remanence was probably acquired syntectonically.