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In the book, Story of Earth-The First 4.5 Billion Years, From Stardust to Living Planet, by Robert Hazen, Chapter 3: He discusses the changing mineral composition of the early Earth's crust from continuous heating, cooling, sinking, and remelting. From mafic magnesium rich dunite, anorthite, pyroxene, peridotite, on to today's predominant more felsic silicon enriched basalt and granite/rhyolite.

As a book directed at laymen, like myself, he does not mention a term for this process of decomposition of the Earth's early crust.

My question then is: What is the term for the process of the early Earth's crust to change its mineral composition over many cycles of melting, rising, cooling and sinking?

Thank you.

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    $\begingroup$ The process is differenciation. It is common to say Mantle differenciation, not sure if what you are asking for is Crust differenciation. $\endgroup$
    – user20559
    Apr 7, 2021 at 18:27
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    $\begingroup$ That's it. Planetary differentiation or crust differentiation. I actually came across differentiation, but was under the impression it applied to separation via gravity or centrifugal forces, not chemical. With your answer I found that Britannica defines planetary/crust differentiation as: " ... chemical separation by partial melting and outgassing of volatiles is termed differentiation. As the interior differentiated, less-dense liquids rose from the melt toward the surface and crystallized to form crust." Many thanks. Open a question, and I'll close this out. $\endgroup$
    – JayJay123
    Apr 8, 2021 at 6:28

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The term you are searching for is differentiation. In Early Earth the Crust was mafic. Remelting cycles created an enrichment in silica and alkali elements, forming basalts and granites.

As it happens on Continental Crust it is commonly referred as Differentiation of the Continental Crust.

Hacker, B.R. et al (2011): "Differentiation of the continental crust by relamination", Earth and Planetary Science Letters, Volume 307, Issues 3–4, Pages 501-516, ISSN 0012-821X, https://doi.org/10.1016/j.epsl.2011.05.024.

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    $\begingroup$ Thanks for the bonus reference and link. Cheers. $\endgroup$
    – JayJay123
    Apr 8, 2021 at 6:30

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