Quantification of the elemental incompatibility sequence, and composition of the “superchondritic” mantle

- “Superchondritic” mantle is demonstrated to be a partially depleted mantle.
- The compatibility sequence of the incompatible elements is quantified.
- Superchondritic mantle composition is derived.

The classic compositional model for the bulk Earth and bulk silicate Earth is the “chondritic” model, in which the refractory elements in the bulk Earth, and the refractory lithophile elements in the bulk silicate Earth, are assumed to be in chondritic proportions. Recent discovery of 142Nd anomalies has challenged this view and there has been discussion of a superchondritic Earth or superchondritic mantle, although an alternative explanation that the 142Nd anomalies are inherited from nucleosynthetic anomaly has also been discussed. If the bulk silicate Earth is not chondritic in terms of refractory and lithophile elements, the foundation for many previous publications would be shifted and the new bulk silicate Earth composition must be estimated. This work quantifies the incompatibility sequence and shows that even if the mantle is “superchondritic”, it is still quantitatively consistent with a partially depleted chondritic mantle. Normalization using chondritic mantle abundances is still appropriate. Furthermore, the major and trace lithophile elemental composition of the proposed “superchondritic” mantle as a partially depleted chondritic mantle is derived.