Fig. 3: Mineralogical and geochemical characteristics of the studied aragonite.
From: Hadal aragonite records venting of stagnant paleoseawater in the hydrated forearc mantle
a Radiating aragonite that infills between brecciated serpentinite clasts. SEM image of aragonite surface showing growth banding (b) and dissolution etch pits (c) in a single aragonite crystal. d Selected REE + Y (REY) patterns of the aragonite samples. e A comparison of C and O isotope data of this study with those of serpentine-hosted carbonate collected during previous dredges and dives. Data for aragonite-bearing serpentinized peridotite recovered from hydrothermal fields are from Eickman et al.31 (Logachev and Gakkei ridges; 2000–4000 mbsl) and Ribeiro et al.28 (Rainbow and Saldanha fields; 2200 mbsl). Aragonite in serpentinized peridotite from the IOT is characterized by negative δ13C values. Negative δ13C values have been reported from the Mariana Trough24, where cold and methane-rich seeps are observed. The red line and pink region indicate the δ18OV-SMOW value and ±1σ range (34.5‰ ± 0.7‰) that is in equilibrium with seawater (δ18OV-SMOW = 0‰) at 1.7 °C. f Relationship between Δ14C and δ13C of aragonite. The modern deep seawater Δ14C value of DIC (−200‰ to −210‰)42 is represented by the green star. The inserted graph is a close-up view of the data. The analytical errors in e and f are substantially smaller than the symbols (Supplementary Table 1).
