Composition of the depleted mantle

We present an estimate for the composition of the depleted mantle (DM), the source for mid‐ocean ridge basalts (MORBs). A combination of approaches is required to estimate the major and trace element abundances in DM. Absolute concentrations of few elements can be estimated directly, and the bulk of the estimates is derived using elemental ratios. The isotopic composition of MORB allows calculation of parent‐daughter ratios. These estimates form the “backbone” of the abundances of the trace elements that make up the Coryell‐Masuda diagram (spider diagram). The remaining elements of the Coryell‐Masuda diagram are estimated through the composition of MORB. A third group of estimates is derived from the elemental…