Figure F5. Compositions of Hole 1271B spinels plotted on the Cr-Al-Mg-Fe2+ face of the spinel composition prism (Irvine, 1965, 1967). Molecular Cr x 100/(Cr + Al) ratio of spinel is plotted against Mg x 100/(Mg + Fe2+) ratio. Compositional fields for Hess Deep Site 895 spinel (East Pacific Rise) and abyssal chromites from Dick and Natland (1996) and Dick and Bullen (1984), respectively.

Figure F5. Compositions of Hole 1271B spinels plotted on the Cr-Al-Mg-Fe²⁺ face of the spinel composition prism (Irvine, 1965, 1967). Molecular Cr x 100/(Cr + Al) ratio of spinel is plotted against Mg x 100/(Mg + Fe²⁺) ratio. Compositional fields for Hess Deep Site 895 spinel (East Pacific Rise) and abyssal chromites from Dick and Natland (1996) and Dick and Bullen (1984), respectively.