2005/11/18 by T. Mark Harrison, Janne Blichert‐Toft, Wolfgang Müller +3 · 1 citation
Earth and Planetary Sciences · #Geological and Geochemical Analysis #Geochemistry and Elemental Analysis #High-pressure geophysics and materials #Hadean #Continental crust #Crust #Geology #Mantle (geology) #Geochemistry #Earth science
paper · doi:10.1126/science.1117926
openalex publication_date 2005/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
The long-favored paradigm for the development of continental crust is one of progressive growth beginning at approximately 4 billion years ago (Ga). To test this hypothesis, we measured initial 176Hf/177Hf values of 4.01- to 4.37-Ga detrital zircons from Jack Hills, Western Australia. epsilonHf (deviations of 176Hf/177Hf from bulk Earth in parts per 10(4)) values show large positive and negative deviations from those of the bulk Earth. Negative values indicate the development of a Lu/Hf reservoir that is consistent with the formation of continental crust (Lu/Hf approximately 0.01), perhaps as early as 4.5 Ga. Positive epsilon(Hf) deviations require early and likely widespread depletion of the upper mantle. These results support the view that continental crust had formed by 4.4 to 4.5 Ga and was rapidly recycled into the mantle.