Abstract:
The Wandilla and Shoalwater terranes of the northern New England Fold Belt are accretionary subduction
complexes formed during the Carboniferous at the convergent plate boundary that
extended along the eastern edge of Palaeozoic Gondwana. Sandstones from the Wandilla terrane
are quartz-poor and quartz-intermediate lithic or feldspathic volcanic sandstones that were derived
principally from the associated magmatic arc, whereas those of the Shoalwater terrane are quartzrich
and were sourced from a cratonic region dominated by low-grade metamorphic and granitic
rocks. The location of the Shoalwater source cannot be determined unambiguously but probably was
situated to the north with detritus supplied longitudinally to the convergent plate boundary. At that
time arc-derived sediment was confined to the forearc basin behind an outer arc ridge, the physiographic
manifestation of the accreted rocks of the Wandilla terrane. The tectonic situation may have
been similar to that of the present-day Lesser Antilles subduction system where quartzose sediment
carried down the Orinoco River is transported northward and incorporated into the Barbados Ridge
subduction complex
