<p>In the book, <em>Story of Earth-The First 4.5 Billion Years, From Stardust to Living Planet</em>, 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.</p>
<p>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.</p>
<p>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?</p>
<p>Thank you.</p>

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2021-04-08T06:28:14.157Z
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.
JayJay123
<geology><minerals><crust>
Term for the Process of the Early Earth's Crust's Changing Mineral Composition
JayJay123
# Term for the Process of the Early Earth's Crust's Changing Mineral Composition

(Asked by: username_0 on 2021-04-07)

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.

**Tags:** geology, minerals, crust

> **Comments:**
> **username_0**: 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.  

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## 0 answers

