Response to Comment on "Heterogeneous Hadean Hafnium: Evidence of Continental Crust at 4.4 to 4.5 Ga"
T. M. Harrison,1,2*
J. Blichert-Toft,3
W. Müller,4
F. Albarede,3
P. Holden,2
S. J. Mojzsis5
Valley
et al. review the lines of evidence on which we drew
to conclude that continental crust formed much earlier than
previously thought. Their comment contains some misrepresentations
that we correct, but new information they provide appears to
bolster our hypothesis. Nothing in their comment refutes the
presence of continental crust or plate boundary processes prior
to 4 billion years ago.
2 Research School of Earth Sciences, Australian National University, Canberra, A.C.T. 0200 Australia.
3 Ecole Normale Superieure, CNRS UMR 5570, 69364 Lyon Cedex 7, France.
4 Department of Geology, Royal Holloway University of London, Egham, TW20 0EX, UK.
5 Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA.
* To whom correspondence should be addressed. E-mail: mark.harrison{at}anu.edu.au
