Kellogg L. H., Hager B. H., R. Van der Hilst, Originally published in Science, 283, pp. 1881-1884, 1999; reproduced by COMPRES Image Library
This illustration from Kellog, Hader, and van der Hilst (1999) shows their vision of a chemically stratified mantle perturbed by the downgoing subducted slabs of oceanic lithospere (blue).
