Fig. 4: Electrical conductivity of three types of carbonated eclogites and the effect of carbonates-silicate cations exchange on it.

a Electrical conductivity of dolomite eclogite as a function of reciprocal temperature. Measured electrical conductivity of 10%, 20%, 30%, and 40% dolomite + eclogite, respectively. b Electrical conductivity of calcite eclogite and magnesite eclogites as a function of reciprocal temperature. Measured electrical conductivity of 10% calcite + eclogite, and 10% and 20% magnesite + eclogite, respectively. Also, the electrical conductivity of carbonated eclogite is compared to that of the initial eclogite, dolomite, Fe-dolomite, calcite, and magnesite as references in (a) and (b). The red star in (a) indicate a shift in electrical conductivity due to the variation of dolomite content in the eclogite. c The relationship between the elevated electrical conductivity of carbonated eclogites and the carbonates-silicate cations exchange. The schematic cube of carbonates + eclogite aggregates represent an carbonated eclogite assemblages. Three types of carbonated eclogites corresponds to three scenarios, i.e., dolomite + eclogite, calcite + eclogite, and magnesite + eclogite, respectively, showing details in the schematic sample cross-Sections 1–3 of the carbonated eclogite cube. Sample cross-Section 1 displays the schematic texture of dolomite eclogite after the EC experiment. The texture of 20% dolomite + eclogite experienced changes before, during, and after EC experiments in the heating-cooling cycles of EC measurement due to the carbonate-silicate reactions. Sample cross-Sections 2 and 3 illustrate the schematic texture of calcite and magnesite eclogite during EC experiments before calcite and magnesite melting, respectively, and show their elements exchange between carbonates and silicates. Schematic minerals aggregate displays the three-dimensional cations exchange paths between carbonates and silicates at the elevated condition. d X_Fe (= wt% FeO/(MgO + FeO)) in dolomite of dolomite eclogites versus the activation enthalpies of the electrical conductivity at high and low temperature (left axis), and the X_Fe versus the electrical conductivity at 673 K and 1373 K (right axis). Dolomite and eclogite are set as references to compare with the dolomite eclogites in (d). The red dashed arrows indicate the increase in electrical conductivity from dolomite or eclogite to dolomite eclogites, and the black indicate the decrease in activation enthalpies.