Figure F71. FeO vs. MgO for troctolites from Site 1275 (blue diamonds). Yellow triangles = Site 1270, 1271, 1272, and 1274 peridotites, open dots = Mid-Atlantic Ridge peridotites from Leg 109 Site 670 and Leg 153 Site 920. Published data are also shown for comparison: open diamonds = Mid-Atlantic Ridge peridotites from Leg 109 Site 670 (Hébert at al., 1990) and Leg 153 Site 920 (Casey, 1997). Other symbols: * = Southwest Indian Ridge (Snow and Dick, 1995), + = Izu-Bonin-Mariana forearc (Parkinson and Pearce, 1998), diamond = East Pacific Rise peridotites (Niu and Hekinian, 1997); X = Western Alps orogenic lherzolites and ophiolites (Bodinier, 1988; Rampone et al., 1996), circle = Oman ophiolite harzburgites (Godard et al., 2000), triangle = Oman ophiolite mantle transition zone dunites (Godard et al., 2000). Whole-rock compositions are presented on a volatile-free basis assuming all Fe is FeO. The solid black lines show olivine and orthopyroxene composition as a function of Fe/Mg. Fine gray lines show constant values of Mg# (Mg# = 100 x molar Mg/[Mg + Fetotal]). Fetotal = total Fe as FeO.

Figure F71. FeO vs. MgO for troctolites from Site 1275 (blue diamonds). Yellow triangles = Site 1270, 1271, 1272, and 1274 peridotites, open dots = Mid-Atlantic Ridge peridotites from Leg 109 Site 670 and Leg 153 Site 920. Published data are also shown for comparison: open diamonds = Mid-Atlantic Ridge peridotites from Leg 109 Site 670 (Hébert at al., 1990) and Leg 153 Site 920 (Casey, 1997). Other symbols: * = Southwest Indian Ridge (Snow and Dick, 1995), + = Izu-Bonin-Mariana forearc (Parkinson and Pearce, 1998), diamond = East Pacific Rise peridotites (Niu and Hekinian, 1997); X = Western Alps orogenic lherzolites and ophiolites (Bodinier, 1988; Rampone et al., 1996), circle = Oman ophiolite harzburgites (Godard et al., 2000), triangle = Oman ophiolite mantle transition zone dunites (Godard et al., 2000). Whole-rock compositions are presented on a volatile-free basis assuming all Fe is FeO. The solid black lines show olivine and orthopyroxene composition as a function of Fe/Mg. Fine gray lines show constant values of Mg# (Mg# = 100 x molar Mg/[Mg + Fe_total]). Fe_total = total Fe as FeO.