Quantification of the elemental incompatibility sequence, and composition of the 鈥渟uperchondritic鈥?mantle

详细信息    查看全文

• 作者：Youxue Zhang
• 关键词：Incompatible elements ; Compatibility sequence ; Superchondritic mantle ; Subchondritic mantle ; Mantle composition
• 刊名：Chemical Geology
• 出版年：13 March, 2014
• 年：2014
• 卷：369
• 期：Complete
• 页码：12-21
• 全文大小：833 K

文摘

The classic compositional model for the bulk Earth and bulk silicate Earth is the 鈥渃hondritic鈥?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 鈥渟uperchondritic鈥? 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 鈥渟uperchondritic鈥?mantle as a partially depleted chondritic mantle is derived.