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Science 16 February 2007:
Vol. 315. no. 5814, pp. 980 - 983
DOI: 10.1126/science.1136154
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Reports

Magmatic and Crustal Differentiation History of Granitic Rocks from Hf-O Isotopes in Zircon

A. I. S. Kemp,1,2* C. J. Hawkesworth,1 G. L. Foster,1 B. A. Paterson,1 J. D. Woodhead,3 J. M. Hergt,3 C. M. Gray,4 M. J. Whitehouse5

Granitic plutonism is the principal agent of crustal differentiation, but linking granite emplacement to crust formation requires knowledge of the magmatic evolution, which is notoriously difficult to reconstruct from bulk rock compositions. We unlocked the plutonic archive through hafnium (Hf) and oxygen (O) isotope analysis of zoned zircon crystals from the classic hornblende-bearing (I-type) granites of eastern Australia. This granite type forms by the reworking of sedimentary materials by mantle-like magmas instead of by remelting ancient metamorphosed igneous rocks as widely believed. I-type magmatism thus drives the coupled growth and differentiation of continental crust.

1 Bristol Isotope Group, Earth Sciences Department, University of Bristol, Bristol BS8 1RJ, UK.
2 School of Earth and Environmental Sciences, James Cook University, Townsville, 4811, Australia.
3 School of Earth Sciences, University of Melbourne, Victoria, 3010, Australia.
4 Centre for Theoretical Isotope Studies, Greensborough, Victoria, 3088, Australia.
5 Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden.

* To whom correspondence should be addressed. E-mail: tony.kemp{at}jcu.edu.au

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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