Archaean plate tectonics

It is perhaps not surprising therefore that an enthusiastic application of the plate tectonic paradigm to Archaean time has delivered mixed results (e.g. see critique by Hamilton 1993, 1998) and, currently, impedes an equally exciting research avenue into what is different about the Archaean Eon and the early Earth , and what this tells us about secular evolution of our planet. A broader view, one naturally promoted by planetary science, is that Earth is just one of several... 

It is critical therefore that we go back to the primary rock record and look for signals of processes other than those that may have had their origin in modern-style plate tectonics. In this context I will discuss some important themes in Archaean geology and highlight those features that perhaps appear uniquely Archaean. As part of this discussion I will present new data from the Slave craton, including the first craton-scale cross-section through this well-exposed fragment of Archaean crust. 

Henderson, J. B. 1981. Archaean basin evolution in the Slave Province, Canada. In Kroner, A. (ed.) Precambrian Plate Tectonics. Elsevier, Amsterdam, 213-235. 

Second, whilst there is no agreement on the detail, it is evident that much of the Archaean mantle was hotter than the modern mantle. This has implications for mantle viscosity. The viscosity of the Earth s mantle shows a strong dependence on temperature to the extent that an upper mantle 250°C hotter than the present day mantle would be 60 times less viscous (Davies, 2006). A lower viscosity will influence patterns of mantle convection and the nature of Archaean tectonics, and would have influenced the size plates in the precursor to modern plate tectonics. 

Bickle, M. j. 1978. Heat loss from the Earth a constraint on Archaean tectonics from the relation between geothermal gradients and the rate of plate production. Earth and Planetary Science Letters, 40, 301-315. 

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