Fig. 6: Geophysical profiles of carbonated eclogites.

a–d Density and P-wave velocity profiles for carbonated eclogites calculated along the hottest and coldest subduction zone geotherms^122,123 using Perple_X 6.9.014. Dry eclogite is associated with the deeply subducting eclogite (depth >～50 km in the hot subduction zone and depth >~100 km in the cold subduction zone), and the hydrous eclogite represents a shallowly subducting eclogite; the presence of hydrous minerals, such as amphibole and epidote, distinguishes one from the other (Supplementary Table 4). Two eclogites, the low-Fe composition (MORB¹³¹) and high-Fe composition (this study), are considered to the impact of the eclogite composition on the density and wave velocity of carbonated eclogite; how much carbonates content is carried by different subducted eclogites into the deep Earth. The term “20% or 40% carbonates + eclogite (or MORB)” refers to the arithmetical average density and P-wave velocity of dry eclogite (low-Fe or high-Fe) containing either 20% or 40% dolomite, magnesite, and calcite eclogites, respectively (details see Supplementary Figs. 8 and 9). The term “Dabie-sulu (or Tianshan) average” refers to the arithmetical average density and P-wave velocity of dry natural carbonated eclogites from Dabie-sulu and Western Tianshan, respectively. This paper focuses on dry carbonated eclogites, but hydrous natural carbonated eclogites (11RC-8E^* from Dabie-sulu and H146-3^* from Western Tianshan in (a–d)) as references. The density of PRAM¹³², MORB eclogite¹³³, pyrolite¹³⁴, and the P-wave velocity of PRAM¹³⁴ and pyrolite¹³⁵ are also as references. The yellow shaded areas present where hydrous mineral in hydrous eclogite undergo dehydration, while blue arrows show how density or P-wave velocity changes from the hydrous to dry systems in hot or cold subduction. Areas of density, velocity and electrical conductivity anomalies are delineated in (a–d) (details see Supplementary Note 6.2). a, c and b, d are the same legends, respectively. e, f Conductivity profiles for carbonated eclogites based on our EC experiments along a hottest and coldest subduction zone geotherms^122,123. e-i Electrical conductivity profiles of exhumated carbonated eclogites along a 60 mWm⁻² continental lithosphere geotherms¹³⁶. The crust conductivity anomalities (σ > 2 S/m) were labeled with a red dashed line. The magnetotelluric anomalities profile of Ladakh Batholith B-B’ in India⁹⁵, Kazakh Platform A-A’ in Tianshan⁹⁶, and Dabie-sulu A-A’ in China⁹⁷ were obtained (details in Supplementary Fig. 10), where carbonated eclogites were reported^{30,32,34,41,74}. e-ii The electrical conductivity profiles of deep subducted carbonated eclogites along a 70 Ma upper mantle geotherms¹³⁷. The electrical conductivity range (−2.5 S/m <log σ < −1 S/m) of the global and regional mantle¹³⁸, the north Pacific and Philippine Sea mantle¹³⁹ are displayed, labeled with a two-way arrow. The shaded light-gray color area (50 km < depth < 250 km in hot subduction zone and depth >100 km in cold subduction zone) represents a ubiquitous region of a dry eclogite¹⁴⁰ and before carbonates melting⁷.