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 November 10, 1983 | Published
Journal Article Open

Chemical Composition of the Mantle


The composition of primitive mantle (54 elements) is estimated by a mass balance approach that does not make a priori assignments of basalt:peridotite ratios or LIL contents of these components. It is also not necessary to assume that such ratios as Rb/Sr and K/U are the same as in the crust. Primitive upper mantle is treated as a four-component system: crust, peridotite, LIL-depleted basalt (MORB), and an LIL-enriched component. These are combined to give chondritic ratios of the oxyphile refractory trace elements. The composition of the whole mantle is estimated by requiring chondritic ratios of the major elements as well. In this way one can estimate the volatile and siderophile content of the mantle. The primitive mantle has K = 152 ppm, U = 0.020 ppm, Th = 0.078 ppm, K/U = 7724, and Rb/Sr = 0.025. The ratios are significantly less than previous estimates. The inferred steady state heat flow, 0.9 μ cal/cm^2s, implies a substantial contribution of cooling to the observed heat flow. The crust and upper mantle may contain most of the terrestrial inventory of the incompatible elements, including K, U, and Th. There is no evidence that the chalcophiles are strongly partitioned into the core.

Additional Information

© 1983 American Geophysical Union. Received April 20, 1983; revised August 16, 1983; accepted August 26, 1983. I would like to thank Jay Bass, John Philpotts, John Morgan, and Robin Brett for extremely useful reviews. This research was supported by National Science Foundation grant EAR 81-15236. This paper is contribution number 3858, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125. Paper number 3B5019.

Attached Files

Published - DLAjgr83c.pdf


Files (924.8 kB)
Name Size Download all
924.8 kB Preview Download

Additional details

August 19, 2023
October 26, 2023