= Solution
\b[The expected broad contrast is a less mature, commonly thinner early juvenile <continental crust>, with more <mafic> material and abundant sodic <tonalite-trondhjemite-granodiorite>, rather than the more differentiated, potassium-rich granitoid component characteristic of much <Phanerozoic> <continental crust>.] This is a secular tendency, not a single stratified column applicable throughout the <Archean>.
<Archean> terrains commonly expose <tonalite-trondhjemite-granodiorite> <gneiss> associated with <greenstone belts> containing <basalt>, <komatiite> and <metasedimentary rocks>. Many later granitoids are richer in <potassium>, including <granite> and <granodiorite>. The proportions changed during the <Archean>: a reconstruction from <trace element> ratios in <sedimentary rocks> infers a markedly <mafic> upper <continental crust> before about 3.0 Ga and a more <felsic> upper <continental crust> by 2.5 Ga. Thus “all Archean continental crust was mafic” would be wrong. A preserved <tonalite-trondhjemite-granodiorite>-dominated nucleus can be strongly <felsic>, including at depth; its composition is not identical to that of its original juvenile precursor.<Archean upper crust transition from mafic to felsic marks the onset of plate tectonics by Ming Tang and others>{ref}
\b[Thickness needs a stated comparison.] An influential seismic compilation found preserved <Archean> <crust> about 27–40 km thick, commonly without the thick high-velocity basal layer of its 40–55 km thick <Proterozoic> comparison provinces. That supports a relatively thin endmember, but is not a measurement of every original <Archean> <continental crust>, nor a demonstration that every <Archean> region was thinner than today's 35–40 km reference column. <Tectonic thickening>, <magmatic underplating>, <erosion>, <delamination> and preservation bias all alter what survives. The very thick <lithospheric mantle> beneath a <craton> must also not be mistaken for thick <continental crust>.<Evolution of the Precambrian lithosphere: Seismological and geochemical constraints by Raymond J. Durrheim and Walter D. Mooney>{ref}
The transferable answer is therefore \b[more <mafic> early juvenile precursors, widespread sodic <tonalite-trondhjemite-granodiorite> production, and variable thickness evolving through time]; late <Archean> <felsic> nuclei can already resemble substantial modern <continental crust>.
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