Table 1 Natural occurrences of metasomatic reaction zones at the contact between crust and mantle rocks
Setting | Occurences | Metasomatic zones hosted by ultramafic rocks | Metasomatic zones hosted by crustal rocks | Serpentine minerals | Gain/loss during alteration of the ultramafic rock | Gain/loss during alteration of the ultramafic rock | References | |
|---|---|---|---|---|---|---|---|---|
Nishisonogi metamorphic rocks | Subduction zone | Serpentinite pods in pelitic schist | Mgs + Qz veins/Tlc + Car (Act)/Car + Qz | Chl/Ms/Ab | Atg | Gain: CO2 Loss: Mg, Ca, H2O | Gain: Mg, Fe, H2O Loss: Si, K, C | Mori et al. (2007) |
Sanbagawa Belt (Higuchi body) | Subduction zone | Serpentinite block in pelitic schist | Car + Tlc veins/Act-Chl schist | Chl | Atg | Gain: Si, Ca, CO2 Loss:Mg, H2O (n.a.) | Gain: Mg, H2O Loss: Si, Na, K | Okamoto et al. (2021) |
Sanbagawa Belt (Tomisato body) | Subduction zone | Serpentinite block in pelitic schist | Tlc + Chl/Tlc veins | Chl/Ms/Ab | Atg | Gain: Si, Ca, Al Loss:Mg, H2O | Gain: Mg, H2O Loss: Si, Na, K | Oyanagi et al. (2023) |
Livingstone fault | Tectonic fault between the Dun Mountain Ophiolite Belt and the Caples terrane | Schist blocks in Serpentine shear zone | Tr vein, Tlc veins/Tr | Rodingite pods (occationary) | Chry/Liz (minor Atg) | Gain: Si, Ca? (n.a.) | n.d | |
Voltri massif | Oceanic lithosphere → Subduction zone | Metagabbro block in schistose serpentinite | No reaction zone (Tlc veins) | Ca-Amp + Chl/Chl + Ca-Amp/Ep | Atg | n.a | Gain: Mg, H2O Loss: Ca (Chl rock) | Collido et al. (2022b) |
Flanciscan Complex (Jade Cove) | Oceanic lithosphere → Subduction zone | Serpentine melange | Tr + Chl, Chl + Tlc | Tr overgrowth + Chl | Liz/Chry → Atg | Gains: Si, Ca Loss: n.a | Gain: Mg? (n.a.) |