Archean dome-and-basin style structures form during growth and death of intraoceanic and continental margin arcs in accretionary orogens

Determining whether plate tectonics or some other mode of planetary dynamics operated in the early Archean is one of the most contentious and debated areas of Earth Sciences today. The Paleo- Mesoarchean dome-and-basin structures of the Eastern Pilbara craton are widely used as an example of an early Archean terrane supposedly unlike any produced by plate tectonics in the current mode of active-lid plate tectonics on Earth. In contrast, we produce a synthesis of the structural, magmatic and sedimentological development of the Eastern Pilbara craton from 3600 to 2800 Ma, and through comparative tectonic analysis, show that the craton developed following a typical orogenic sequence from an immature oceanic arc-dominated accretionary orogen, with the oldest rocks of the craton represented by slabs of primitive circa 3590 Ma gabbro - anorthosite - ultramafic rocks, and 3522–3426 Ma oceanic crust and overlying dominantly hydrothermal deep-water cherts imbricated in thrust piles and giant recumbent nappes. These were intruded by juvenile arc magmas including gabbros, diorites, and TTG suites, most of which intruded as sills into structurally favorable sites between 3484 and 3416 Ma. These oceanic crust and overlying sedimentary litho-tectonic assemblages of gabbro/ basalt/ komatiite/ chert, and TTG-diorite-dominated plutonic rocks were deformed into imbricate and antiformal thrust stacks intruded by suites of sheet-like TTG magmas during late regional shortening-related deformation at 3318–3290 Ma, then soon-after, folded by upright folds during continued contractional deformation. The intrusive style, compositions, and relationships to structures suggest that the late magmatic suites represent a massive slab-failure magmatic event similar to those formed during arc accretion and slab failure events in the North and South American Cordilleras, and older orogens of all ages. Late-orogenic shortening deformed these sheet intrusions into large domal structures, synchronous with or soon-after late- to post-orogenic cross-cutting steep-walled circa 3274–3223 Ma plutons vertically intruded the cores of some of the domes, forming nested plutons akin to the Cretaceous Sierra Crest Suite of the Sierra Nevada batholith, and deformed equivalents in Phanerozoic orogens. In a much younger magmatic event, a wide swath of the craton was affected by circa 2851–2831 monzogranite intrusions, after which the magmatic events of the Archean of the Eastern Pilbara were terminated by the circa 2772 Ma Black Range dolerite dike swarm, that preserves evidence for rapid APW drift during its intrusion. The Eastern Pilbara represents only a very small preserved Paleo-Mesoarchean crustal remnant, measuring a mere 200 × 200 km2, yet has been frequently used to model the presumed tectonic behavior of the entire planet for much of the Archean. In this synthesis, we show that the scale of the craton renders its significance in this literature greatly exaggerated. The Eastern Pilbara is only 1/3 the size of just the Sierra Nevada batholith. Considering the entire Eastern, Central and Western Pilbara belts, the scale and tectonic zonation of lithotectonic assemblages is remarkably similar to that of the California section of the North American Cordillera, from arc root (Eastern Pilbara. cf. Sierra Nevada), to fore-arc overlap basin (de Gray Basin, cf. Great Central Valley Sequence), to an accretionary complex (Western Pilbara, cf. Franciscan). The duration of different magmatic and deformational events, confined to three main pulses in 300 Ma, including about six total magmatic suites over 500 Ma, is similar to that of different pulses and/or accretionary events in the western American Cordilleran examples, such as the peri-Gondwanan Famatinian (Cambro-Ordovician) and Pampean (Cambrian) arcs which were later affected by Permian and Mesozoic intrusives from the Peruvian coastal batholith, and form part of the present day active Andean margin of South America. From this analysis, we firmly conclude from four degrees of similarity of the full data set of field, structural, temporal, and compositional data that the evolution of the craton is readily and rather simply explained by the plate tectonic paradigm. Thus there is no scientific justification to suggest that the geological characteristics of the Eastern Pilbara require any different imaginative or fantastic type of planetary heat loss mode during the interval of its formation from 3600 to 2800 Ma. The Eastern Pilbara is simply an exceptionally well-preserved small fragment of a poly-phase root of a continental margin accretionary orogen that evolved from accretion and magmatism from some of Earth oldest telescoped oceans and included arcs, in a regime of accretionary-style plate tectonics. Comparison with other well-preserved Eo-Mesoarchean terranes shows a common trait, that of derivation from immature introceanic accretionary orogens, building Earth's first continents.