Evolution of planetary cores and the Earth-Moon system from Nb/Ta systematics

authored by

Carsten Münker, Jörg A. Pfänder, Stefan Weyer, Anette Büchl, Thorsten Kleine, Klaus Mezger

Abstract

It has been assumed that Nb and Ta are not fractionated during differentiation processes on terrestrial planets and that both elements are lithophile. High-precision measurements of Nb/Ta and Zr/Hf reveal that Nb is moderately siderophile at high pressures. Nb/Ta values in the bulk silicate Earth (14.0 ± 0.3) and the Moon (17.0 ± 0.8) are below the chondritic ratio of 19.9 ± 0.6, in contrast to Mars and asteroids. The lunar Nb/Ta constrains the mass fraction of impactor material in the Moon to less than 65%. Moreover, the Moon-forming impact can be linked in time with the final core-mantle equilibration on Earth 4.533 billion years ago.

External Organisation(s)

University of Münster
Goethe University Frankfurt
Max Planck Institute for Chemistry (Otto Hahn Institute)

Type

Article

Journal

SCIENCE

Volume

301

Pages

84-87

No. of pages

4

ISSN

0036-8075

Publication date

04.07.2003

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General

Electronic version(s)

https://doi.org/10.1126/science.1084662 (Access: Unknown)