Figure F60. Primitive mantle-normalized Nb/Ce, Zr/Ti, and Nb/Zr vs. Zr/Y ratio or Zr content. These ratios are sensitive to the presence of a component from continental crust. Note that basalts from Site 738, which have been shown to contain such a continental component, have the lowest Nb/Ce and Nb/Zr and highest Zr/Ti values. Site 1137 basalts have a comparable Zr/Ti range but higher Nb and Zr contents and, consequently, higher Zr/Y, Nb/Ce, and Nb/Zr. Ratios are normalized using estimated primitive-mantle abundances of Sun and McDonough (1989). Data sources are the same as in Figure F54.