EARLY PERMIAN TRANSFORM MARGIN DEVELOPMENT OF THE SOUTHERN NEW-ENGLAND OROGEN, EASTERN AUSTRALIA (EASTERN GONDWANA)

The southern New England orogen, part of the eastern margin of Gondwana, evolved from a zone of high-angle plate convergence during the Carboniferous, into either a transform margin or a highly oblique-convergent margin by the Early Permian. Fault-bounded, narrow, elongate, rapidly filled sedimentary basins that developed along the Peel-Manning fault system in the Early Permian provide support for this hypothesis. They are similar to sedimentary basins developed along strike-slip fault zones worldwide. Strike-slip dislocations provide the best explanation for juxtaposition of terranes with distinctly different geological histories and discontinuities in regional geological trends across these basins. A close spatial relationship also exists between occurrences of serpentinite-matrix ophiolitic melange, the Peel-Manning fault system, and related secondary faults. Early Permian transtension may have facilitated the diapiric rise of serpentinites, which originated from an older underlying ultramafic precursor, up these fault zones. Rise and Early Permian emplacement of the Bundarra Plutonic Suite, an S-type batholith across which regional geological trends are offset, is also best accommodated in a model that involves a transtensional regime.