Continental Growth Model

Most crustal provinces less than 2.5 Ga include variable amounts of reworked older crust. Early Archean, which is older than 3.5 Ga, crustal provinces are small and may represent remnants of the early Earth continents, even though they are widely distributed. Late Archean provinces (3.0 - 2.5 Ga) are general on all continents and perhaps underlie much of the platform sediment in Canada, Africa, Antarctica, and Siberia. Paleoproterozoic provinces (2.0 - 1.7 Ga) are widespread in North America and in the Baltic shield in Europe, and they form less common but significant orogens in South America, Africa, and Australia. Mesoproterozoic provinces (mainly 1.3–1.0 Ga) occur on almost all continents, where they form narrow belts along which the Mesoproterozoic supercontinent Rodinia was sutured. Unlike older crustal provinces, little juvenile crust is known of this age. Neoproterozoic provinces (0.8–0.55 Ga) are dominant only in South America, Africa, southern Asia.

Conclusion

Understanding the origin and evolution of the crust by looking at seismic, geological data and modeling has done in this paper. Although the preserved old rocks are limited, still they play remarkable role to indicate the presence of felsic rocks. Geochemical data suggest the crustal origin and verify the continental growth model. There are two major mechanisms of continental growth, which is magmatic underplating and terrane collisions. Besides, continental crust grows by mafic underplating, oceanic plateau, and plate collisions. The rates of continental growth can be calculated with various models. The role of recycling dominants this rate of continental growth. Active plate settings have less recycling half-lives, so be recycled much faster than continental cratons. Surprisingly, the origin and evolution of continental crust are significantly different with oceanic crust, much more complicated.