Plate tectonics is a global process in which partially hydrated and dense oceanic lithosphere
is recycled in long lived subduction zones. Although prevalent throughout the Phanerozoic,
it is unclear whether, or to what extent, this process operated during the Archean (4.0-2.5
Ga) when mantle heat flow was higher, and the lithosphere was perhaps less differentiated
(Brown, 2014; Kamber, 2015). Critical to this debate is the interpretation of tonalite-
trondhjemite-granodiorite (TTG) complexes, which make up 90% of the preserved Archean …