Early history of Earth's crust-mantle system inferred from hafnium isotopes in chondrites
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Early history of Earth's crust-mantle system inferred from hafnium isotopes in chondrites. / Bizzarro, Martin; Haack, Henning; Rosing, M.; Baker, J.A.; Ulfbeck, D.
In: Nature, Vol. 421, No. 6926, 2003, p. 931-933.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Early history of Earth's crust-mantle system inferred from hafnium isotopes in chondrites
AU - Bizzarro, Martin
AU - Haack, Henning
AU - Rosing, M.
AU - Baker, J.A.
AU - Ulfbeck, D.
PY - 2003
Y1 - 2003
N2 - The Lu to Hf decay series has been widely used to understand the nature of Earth's early crust-mantle system. The interpretation, however, of Lu-Hf isotope data requires accurate knowledge of the radioactive decay constant of Lu (¿176), as well as bulk-Earth reference parameters. A recent calibration of the ¿176 value calls for the presence of highly unradiogenic hafnium in terrestrial zircons with ages greater than 3.9 Gyr, implying widespread continental crust extraction from an isotopically enriched mantle source more than 4.3 Gyr ago, but does not provide evidence for a complementary depleted mantle reservoir. Here we report Lu-Hf isotope measurements of different Solar System objects including chondrites and basaltic eucrites. The chondrites define a Lu-Hf isochron with an initial Hf/Hf ratio of 0.279628 ± 0.000047, corresponding to ¿176 = 1.983 ± 0.033 x 10yr using an age of 4.56 Gyr for the chondrite-forming event. This ¿176 value indicates that Earth's oldest minerals were derived from melts of a mantle source with a time-integrated history of depletion rather than enrichment. The depletion event must have occurred no later than 320 Myr after planetary accretion, consistent with timing inferred from extinct radionuclides.
AB - The Lu to Hf decay series has been widely used to understand the nature of Earth's early crust-mantle system. The interpretation, however, of Lu-Hf isotope data requires accurate knowledge of the radioactive decay constant of Lu (¿176), as well as bulk-Earth reference parameters. A recent calibration of the ¿176 value calls for the presence of highly unradiogenic hafnium in terrestrial zircons with ages greater than 3.9 Gyr, implying widespread continental crust extraction from an isotopically enriched mantle source more than 4.3 Gyr ago, but does not provide evidence for a complementary depleted mantle reservoir. Here we report Lu-Hf isotope measurements of different Solar System objects including chondrites and basaltic eucrites. The chondrites define a Lu-Hf isochron with an initial Hf/Hf ratio of 0.279628 ± 0.000047, corresponding to ¿176 = 1.983 ± 0.033 x 10yr using an age of 4.56 Gyr for the chondrite-forming event. This ¿176 value indicates that Earth's oldest minerals were derived from melts of a mantle source with a time-integrated history of depletion rather than enrichment. The depletion event must have occurred no later than 320 Myr after planetary accretion, consistent with timing inferred from extinct radionuclides.
UR - http://www.scopus.com/inward/record.url?scp=0037468174&partnerID=8YFLogxK
U2 - 10.1038/nature01421
DO - 10.1038/nature01421
M3 - Journal article
C2 - 12606997
AN - SCOPUS:0037468174
VL - 421
SP - 931
EP - 933
JO - Nature
JF - Nature
SN - 0028-0836
IS - 6926
ER -
ID: 77340