Pre-plate tectonics and origin of continents

Water‐Induced Mantle Overturns Leading to the Origins of Archean Continents and Subcontinental Lithospheric Mantle

“…Water‐induced mantle overturns avoid a fatal drawback in the oceanic plateau model for the origin of continents (e.g., Arndt, 2013; Martin et al., 2014; Wu & Zhao, 2022), which cannot well explain the source of H 2 O that is needed for the partial melting of mafic oceanic plateau crust to form tonalite‐trondhjemite‐granodiorite (TTG) magmas. Although the island arc models can interpret the origin of both high‐pressure and low‐pressure Archean TTG rocks as subducting slabs can provide sufficient water, the plate tectonic theory meets fundamental challenges in interpreting the origin of Archean continental crust (e.g., Bédard, 2006; Bédard, 2018; Van Kranendonk et al., 2007; Zhao & Zhang, 2021; Zhao et al., 2022; Zhu et al., 2021). Instead, the oceanic plateau model of mantle plumes for the origin of continents is supported by the growing lines of evidence such as the extensive appearance of komatiites or komatiitic rocks in the Archean greenstones, emplacement of the Archean TTG across a whole cratonic block within a short period, absence of any systematic progression in TTG ages, dome‐and‐keel structures, and isobaric‐cooling metamorphism characterized by an anticlockwise P‒T path (e.g., G. Zhao & Zhang, 2021; Zhu et al., 2021).…”

Water-induced mantle overturns leading to the origination of Archean continents and sub continental lithospheric mantle

“…The water-induced mantle overturns avoid a fatal drawback on the oceanic plateau model for the origin of continents 13,21,22 , which cannot well explain the source of H 2 O that is needed for the partial melting of mafic oceanic plateau crust to form the tonalitetrondhjemite-granodiorite (TTG) magmas. Although the island arc models can interpret the origin of both high-pressure and low-pressure Archean TTG rocks as subducting slabs can provide sufficient water, the plate tectonic theory meets fundamental challenges in interpreting the origin of the Archean continental crust 11,23,24 . Instead, the oceanic plateau model of mantle plumes for the origin of continents is supported by the growing lines of evidence such as the extensive appearance of komatiites or komatiitic rocks in the Archean greenstones, emplacement of the Archean TTG cross over a whole cratonic block within a short period, absence of any systematic progression in TTG ages, dome-and-keel structures, and isobaric-cooling metamorphism characterized by an anticlockwise P-T path 11,24 .…”