Short-lived chemical heterogeneities in the archean mantle with implications for mantle convection.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 17744788.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
The neodymium isotope and samarium-neodymium systematics of 2.7-billion-year-old mantle-derived magmas indicate that the lifetime of chemical heterogeneities was much shorter in the Archean mantle than in the modern mantle. Isotopic evidence is compatible with a Rayleigh number 100 times larger and convection 10 times faster in the Late Archean compared with the present-day mantle. Modern plate tectonics thus may be an improbable analog for the Archean. Chemical heterogeneities in the mantle may originate upon magma migration and mineralogical phase changes rather than by recycling of oceanic and continental crust.