Fig. 3: Distribution of Fo–Ni contents among the different crystal groups and variations along selected crystal profiles.
From: Out-of-sequence skeletal growth causing oscillatory zoning in arc olivines
a Olivine groups separated by color show that the texturally mature crystals tend to be more primitive whereas the immature olivines are compositionally more evolved. b Core to rim profiles of selected crystals. Note the core compositions falling in a restricted Fo–Ni space (gray circle). Rimward, the color-coded crystals share a common evolution pattern, characterized by a sharp Ni decrease accompanied by only a slight variation of Fo, followed by abrupt increments of Ni-only variations at approximately constant Fo. Close to the margins, the crystals chemistry is consistent with co-crystallization of olivine + clinopyroxene ± plagioclase along the crystallization path. c Schematic illustration of the evolution pattern of a -core to rim- section of a model crystal. Labels indicate the crystallization conditions of the different slopes of segments (a–d). The alternative path in segment d shows that some crystals may experience multiple sequences of externally developed crystal frames and Ni depletions followed by a return to equilibrium crystallization, e.g., Olivine 50. CBL: compositional boundary layer. Crystallization lines after Ruprecht and Plank3 and mantle peridotite field after Straub et al.71.
