Fig. 5
Partial melting processes in Mars and Earth. Niobium–zirconium–yttrium discrimination diagrams showing a terrestrial mid-ocean ridge basalts (MORB) and Hawaiian main shield building and rejuvenated phase lavas. Partial melt models show melting of a terrestrial depleted mantle source and a metasomatized mantle source, containing amphibole and rutile. Gray dashed lines denote envelope of total variation seen in Icelandic samples using this type of plot. Lines in red are a primitive mantle model, lines in black are a depleted mantle model, and the green line is the exhaustion vector for rutile (Rt), amphibole (Amp), and garnet (Gt) in a metasomatized martian mantle source. Numbers (0.1, 1, 5, 10) associated with dashed tie lines between pure garnet and spinel endmembers are partial melt increments in percent, and Sp is spinel. b Comparison of martian meteorites with terrestrial lavas. Crossed circle is the terrestrial continental crust composition. Model parameters and data sources are given in the Methods section and analytical uncertainties are smaller than symbols
