Fig. 1: Microstructural features of antigorite serpentinization.
From: Subduction hides high-pressure sources of energy that may feed the deep subsurface biosphere
a–c Examples of statically serpentinized pseudotachylyte (S-Pdt)-bearing peridotite from the blueschist-facies Cima di Gratera unit (a) and the eclogite-facies San Petrone unit (b, c). Note the absence of post-pseudotachylyte ductile deformation. d Backscattered-electron image showing the stage of incipient serpentinization proceeding along pre-existing deformation bands characterized by olivine subgains (Ol2) (see Supplementary Fig. 2 for details). Note the presence of awaruite (Aw) in association with antigorite. e Photomicrograph showing the early transformation of orthopyroxene relative to mantle olivine (see Supplementary Fig. 7 for mineralogical details). f Backscattered-electron image showing the formation of metamorphic olivine (M-Ol) together with antigorite during high-pressure serpentinization. Note the difference between the secondary olivine formed along a pre-serpentinization cataclastic band (d) and the metamorphic olivine related to the serpentinization event. Scale bars: a, b 600 µm; c, e 350 µm; d 20 µm; f 40 µm. Other mineral abbreviations: Atg antigorite, Mt magnetite, S-Px serpentinized mantle pyroxene, Ol mantle olivine.
