Figure F81. FeO vs. MgO whole-rock concentrations of Site 1268 peridotites (solid circles). Published data are also shown for comparison (open circles): Mid-Atlantic Ridge peridotites from Leg 109, Site 670, and Leg 153, Site 920. Abyssal peridotites = Southwest Indian Ridge (Snow and Dick, 1995) and Izu-Bonin-Mariana forearc (Parkinson and Pearce, 1998); W. Alps peridotites = western Alps orogenic lherzolites and ophiolites (Bodinier, 1988; Rampone et al., 1996), Oman Hz = Oman ophiolite harzburgites (Godard et al., 2000). Whole-rock compositions are presented on a volatile-free basis. The solid black lines show the variation of olivine composition constrained by FeO + MgO = 66.67 mol% and that of orthopyroxene constrained by FeO + MgO = 50 mol%. Fine gray lines show constant Mg# values (Mg# = 100 x molar Mg/[Mg + Fetotal]). Fetotal = total Fe as FeO.

Figure F81. FeO vs. MgO whole-rock concentrations of Site 1268 peridotites (solid circles). Published data are also shown for comparison (open circles): Mid-Atlantic Ridge peridotites from Leg 109, Site 670, and Leg 153, Site 920. Abyssal peridotites = Southwest Indian Ridge (Snow and Dick, 1995) and Izu-Bonin-Mariana forearc (Parkinson and Pearce, 1998); W. Alps peridotites = western Alps orogenic lherzolites and ophiolites (Bodinier, 1988; Rampone et al., 1996), Oman Hz = Oman ophiolite harzburgites (Godard et al., 2000). Whole-rock compositions are presented on a volatile-free basis. The solid black lines show the variation of olivine composition constrained by FeO + MgO = 66.67 mol% and that of orthopyroxene constrained by FeO + MgO = 50 mol%. Fine gray lines show constant Mg# values (Mg# = 100 x molar Mg/[Mg + Fe_total]). Fe_total = total Fe as FeO.