Continental growth progressive

Common to all crustal growth models is that simple cmstal extraction using the known amount of Early Archean cmst cannot readily account for the degree of depletion evident in some interpretations of the initial and enr compositions of the Archean mantle (Section 2.13.2). In the next sections, the effects of processes other than progressive growth of the continental cmst from a depleting mantle are considered. 

McCulloch M. T. and Bennett V. C. (1994) Progressive Growth of the Earth s continental crust and depleted mantle, geochemical constraints. Geochim. Cosmochim. Acta 58, 4717-4738. 

The Earth is the only planet amongst the rocky planets of the solar system to possess a well-developed, felsic continental crust. This crust was progressively extracted from the Earth s mantle over the last 4.0 billion years, and although it only represents 0.6% of the mass of the silicate Earth, it contains up 70% of the Earth s budget of highly incompatible elements. Over Earth history, the reservoir of depleted mantle, from which the crust was created, has grown in volume to mirror the growth of the continental crust. 

Taken together, the age data for crustal rocks, for which there is now a very extensive database, strongly support a progressive model for the growth of the continental crust. 

Their best-fit models are shown in Fig. 4.8 and support a progressive growth model for the continental crust, with about 50% crust formed by the end of the Archaean. Their calculations show that there was little crustal recycling before the mid-Proterozoic. 

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