Crustal growth models

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. 

Kamber B. S., Ewart A., Collerson K. D., Bruce M. C., and McDonald G. D. (2002) Fluid-mobile trace element constraints on the role of slab melting and imphcations for Archean crustal growth models. Contrib. Mineral Petrol. 144, 38-56. 

The age distribution of crustal rocks An estimate of the relative volumes of continental crust of different ages is an obvious way to assess crustal growth models. However, making such an estimate is not straightforward for two reasons. First, it cannot be assumed that the age of the continents is the same at depth as it is at the surface (Corfu, 1987). Second, the reworking of older crust... 

This result could imply that there was an extensive volume of continental crust in existence at 3.5 Ga, strongly supporting the "nogrowth" crustal growth model of Armstrong (1968). However, there are problems with this interpretation. First, because Nb exchange between the crust and mantle is not a simple two-component system (see Section 4.5.1.2.3) and second, because U is mobile in an oxidizing... 

De Paolo, D. J. (1980). Crustal growth and mantle evolution inferences from models of element transport and Nd and Sr isotopes. Geochim. Cosmochim. Acta, 44, 1185-96. 

Drummond, M.S. Defant, M.J. 1990. A model for trondhjemite-tonalite-dacite genesis and crustal growth via slab melting Archean to modern comparison. Journal of Geophysical Research, 95, 21503-21521. 

Puchtel I. S., Hofmann A. W., Mezger K., Jochum K. P., Shchipansky A. A., and Samsonov A. V. (1998) Oceanic plateau model for continental crustal growth in the Archaean a case study from the Kostomuksha greenstone belt, NW Baltic Shield. Earth Planet. Sci. Lett. 155, 57-74. 

Rudnick R. L. (1990b) Nd and Sr isotopic compositions of lower crustal xenoliths from North Queensland, Australia implications for Nd model ages and crustal growth processes. Chem. Geol. 83, 195 - 208. 

If the model outlined above is valid, sihcic magmatism in the LFB involved net crustal growth, as juvenile mantle-derived liquids, or their differentiates were instrumental in the formation and compositional evolution of hornblende granites, and, to a lesser extent, the cordierite granites. The amount of new crust generated is estimated by determining the overall mantle component present within both granitic types, and this is best done isotopically, since the trace-element ratios are poorly constrained for the potential basaltic end-members. 

Seismic evidence for a mantle source for mid-Proterozoic anorthosites and implications for models of crustal growth... 

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