Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published 1981 | public
Book Section - Chapter

Geophysical and cosmochemical constraints on properties of mantles of the terrestrial planets


Basalts are understood to be derived by partial melting from the mantles of their planets, and properties of the basalt samples we have been able to obtain (from Earth, the Moon, and the parent planets of the basaltic achondrite meteorites) have been an invaluable source of information about the composition and nature of the mantles of these bodies (Chapter 3). There is little doubt that basaltic volcanism has also been active on the planets that we have not been able to sample; in several cases, the surface morphologies and photometric properties of these planets strongly indicate the action of basaltic volcanism (Chapters 5 and 2). The purpose of this chapter is to infer as much as we can, by means other than sampling, about the compositions of planetary mantles. Our estimates of mantle compositions provide a basis for experimental petrologists to project the possible compositions of basalts that would be erupted on unsampled planets (Chapter 3). The clues we have to mantle compositions, apart from directly sampling them and the basalts that issue from them, are (I) the gross geophysical properties of the planets in question and (2) our estimates of their bulk compositions. Fragmentary chemical information comes to us from sources such as spectral studies of planetary atmospheres and surface regoliths, but most of our chemical constraints are based on broader considerations of the overall composition of the solar system and the early processes that appear to have caused the terrestrial planets to incorporate varying proportions of the elements. The geophysical constraints are reviewed in section 4.2, below; the admittedly speculative question of chemical processes that affected the origin and bulk compositions of the planets (cosmochemistry) is treated in section 4.3. Section 4.4 describes the process of planetary modelling by which the most probable mantle compositions, or compositional profiles, are derived from these inputs. Finally, section 4.5 carries out this modelling exercise for the terrestrial planets and Earth's moon, discussing the most likely mantle properties for each body.

Additional Information

© 1993 Pergamon Press. The Team Leader gratefully acknowledges the patience and support of Team members through six iterations of the chapter, and also the help of the LPI Staff, particularly Rosanna Ridings. D. H. Johnston, M. N. Toksoz and S. J. Weidenschilling contributed to early planning of the chapter. M. J. Drake, K. A. Goettel, G. V. Latham, E. Schonfeld, N. H. Sleep, S. C. Solomon and D. Walker provided thoughtful reviews of the product. F. P. Fanale, J. S. Lewis and K. K. Turekian participated in an LPI workshop on cosmochemical models early in the project. M. J. Drake and G. McLaughlin contributed the frontispiece photograph. The contributions of Team members were supported in part by the following research grants: NASA NGL 09-015-150 (JAW), NGL 14-001-167 (EA), NGL 05-002-069 (DLA), NSG-7081 (WRB), NGL 22-007-269 (GC), NGL 05-007-002 (WMK), and NASA contract T4089 (JM). H. Wanke gratefully acknowledges the financial support of the Deutsche Forschungsgemeinschaft.

Additional details

August 22, 2023
October 18, 2023