Late Archaean deep-marine volcaniclastic sedimentation in an arc-related basin: The Kalgoorlie Sequence of the Eastern Goldfields Superterrane, Yilgarn Craton, Western Australia

The Kalgoorlie Sequence (<2690 to >2658 Ma) is a >3000 m-thick succession of volcaniclastic sedimentary rocks and subordinate rhyolite, dacite, andesite and basalt spatially and temporally associated with subvolcanic sills and dykes of rhyolite and dacite, gabbro sills and I-type granitoids. Although basalts are tholeiitic, the felsic rocks have TTD affinity. The sequence comprises mostly deep-marine channel–levee turbidite complexes and hemipelagites. Resedimented syneruptive volcaniclastic deposits are associated with coherent lavas, but almost all of the sedimentary fill was recycled from prior-cycle volcanic and volcaniclastic sources. Provenance was mainly dacitic/rhyolitic, with minor andesitic, basaltic and polymictic compositions. Volcano-bound and fault-bound architectures, and two styles of basin filling are identified: progradational or aggradational transverse fans and slope-aprons, and retrogradational longitudinal fans of a linear trough. Retrogradation in longitudinal systems is consistent with basin lengthening and deepening. Six depositional sequences are grouped in four unconformity bounded tectonic stages that record uplift-subsidence cycles. Coeval mafic and felsic magmatism indicate that the tectonic stages represent extensional tectonic settings, whereas volcanogenic provenance, spatially linked volcanism and plutonic magmatism, and deep-marine environments support an intra-arc site. Cyclic uplift-subsidence and basin lengthening are more consistent with strike-slip controls on basin formation than with orthogonal extension. The tectonic setting is interpreted to have been a pull-apart basin associated with strike-slip faulting and amalgamating arc-related terranes, similar to the modern Philippines Archipelago. The strong similarity between Archaean volcaniclastic and modern arc-related volcaniclastic environments implies comparable tectonic settings, and therefore comparable controlling tectonic factors.