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Updated: May 13, 2026

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod
Published on: August 17, 2016
147Sm-143Nd systematics of Earth are inconsistent with a superchondritic Sm/Nd ratio
Shichun Huang1, Stein B Jacobsen, Sujoy Mukhopadhyay
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA. huang17@fas.harvard.edu
Abstract:
The relationship between the compositions of the Earth and chondritic meteorites is at the center of many important debates. A basic assumption in most models for the Earth's composition is that the refractory elements are present in chondritic proportions relative to each other. This assumption is now challenged by recent (142)Nd/(144)Nd ratio studies suggesting that the bulk silicate Earth (BSE) might have an Sm/Nd ratio 6% higher than chondrites (i.e., the BSE is superchondritic). This has led to the proposal that the present-day (143)Nd/(144)Nd ratio of BSE is similar to that of some deep mantle plumes rather than chondrites. Our reexamination of the long-lived (147)Sm-(143)Nd isotope systematics of the depleted mantle and the continental crust shows that the BSE, reconstructed using the depleted mantle and continental crust, has (143)Nd/(144)Nd and Sm/Nd ratios close to chondritic values. The small difference in the ratio of (142)Nd/(144)Nd between ordinary chondrites and the Earth must be due to a process different from mantle-crust differentiation, such as incomplete mixing of distinct nucleosynthetic components in the solar nebula.
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