Granite-greenstone belt terrain

Another approach is to follow a genetic model for continental crust formation, for example in island arcs, oceanic plateaus or Archean granite-greenstone terrains. For example, the full vertical crustal sequence of a mature island-arc has been reconstructed in the Hidaka belt in Hokkaido, Japan over a total thickness of 30 km. This arc contains high-grade metamorphic rocks representative of lower crustal material and its average rate of crustal heat generation is 0.83 p.W m (Furukawa and Uyeda, 1989 Furukawa and Shinjoe, 1997). 

Ga granrtoids 2.90-2 78 Ga fetsic voicanics 2.63 Ga sediments c. 3.0 Ga setkmenis pre-3 35 Ga felsic crust greenstone belt granite-grieiss terrains... 

Fedo, C. M., Eriksson, K. A. Blenkinsop, T. G. 1995. Geologic history of the Archean Buhwa greenstone belt and surrounding granite-gneiss terrain, Zimbabwe, with implications for the evolution of the Limpopo Belt. Canadian Journal of Earth Sciences, 32 1977-1990. 

Of these, late Archaean sedimentary basins are the most "modern" in their form and can be clearly recognized as upper crust. Similarly, the relatively low metamorphic grade of many Archaean greenstone belts indicates that they too represent upper Archaean crust. In contrast, Archaean granite-gneiss terrains more commonly belong to the deeper continental crust and variously represent middle to lower continental crust. There are only a few places... 

Archaean Cratons contain three different types of lithological association, each of which provides important information about the early stages of the Earth System. These associations are Archaean greenstone belts, late Archaean sedimentary basins, and Archaean granite-gneiss terrains. We will consider each in turn. 

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