Australia: The Land Where Time Began

A biography of the Australian continent 

Archaean Continental Crust and Subcontinental lithospheric Mantle – Coupled Evolution

According to Rollinson it has been observed that the composition of the Archaean continental crust and the subcontinental lithospheric mantle (SCLM) differ from their counterparts from the Phanerozoic. The komatiite extraction models for the origin of the SCLM do not work, and the formation of non-arc Archaean basalts are not necessarily formed in a plume setting are used to challenge the mantle plume model for the Archaean SCLM formation. The SCLM is suggested by petrological modelling to have formed at a hot ocean ridge, which gave rise to Fe-rich basaltic ocean crust and thick ocean lithosphere that was highly depleted. This lithosphere would typically not subduct, though where slab melting and tonalite-trondhjemite-granodiorite (TTG) was produced the SCLM that is coupled to felsic crust would be buoyant enough to be conserved. Therefore Archaean SCLM is transposed normal Archaean oceanic lithosphere that was formed at a hot ridge.

Sources & Further reading

1. Rollinson, H. (2010). "Coupled evolution of Archean continental crust and subcontinental lithospheric mantle." Geology 38(12): 1083-1086.