Journal article
Hf-Nd isotope evidence for a transient dynamic regime in the early terrestrial mantle
Nature (London), Vol.404(6777), pp.488-490
03/30/2000
Handle:
https://hdl.handle.net/2376/113130
PMID: 10761914
Abstract
Modern basalts have seemingly lost all 'memory' of the primitive
Earth's mantle except for an ambiguous isotopic signal observed in some rare
gases. Although the Earth is expected to have reached a
thermal steady state within several hundred million years (refs
3, 4) of accretion, it is not known
how and when the initial chemical fractionations left over from planetary
accretion (and perhaps a stage involving a magma ocean) were overshadowed
by fractionations imposed by modern-style geodynamics. Because of the lack
of samples older than 4 Gyr, this early dynamic regime of the Earth is poorly
understood. Here we compare published Hf-Nd isotope data on supracrustals
from Isua, Greenland, with similar data on lunar rocks and the SNC (martian)
meteorites, and show that, about 3.8 Gyr ago, the geochemical signature of
the Archaean mantle was partly inherited from the initial differentiation
of the Earth. The observed features seem to indicate that the planet at that
time was still losing a substantial amount of primordial heat. The survival
of remnants from an early layering in the modern deep mantle may account for
some unexplained seismological, thermal and geochemical characteristics of
the Earth as observed today.
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Details
- Title
- Hf-Nd isotope evidence for a transient dynamic regime in the early terrestrial mantle
- Creators
- Jeffrey D Vervoort - University of ArizonaFrancis Albarède - Ecole Normale Supérieure de LyonJames D Gleason - Ecole Normale Supérieure de LyonMinik Rosing - Geologisk MuseumJanne Blichert-Toft - Ecole Normale Supérieure de Lyon
- Publication Details
- Nature (London), Vol.404(6777), pp.488-490
- Academic Unit
- Environment, School of the (CAS)
- Identifiers
- 99900547941901842
- Language
- English
- Resource Type
- Journal article