Tracing decarbonated eclogite in the mantle sources of Tarim continental flood basalts using Zn isotopes

Recycled oceanic crust is believed to have played an important role in the formation of continental flood basalts, whereas involvement large amounts CO2 derived from recycled marine carbonate their mantle sources highly debated. Zn isotopes great potential trace due distinctly different δ66Zn values between carbonates and mantle. Representative basalt samples Keping (Group1) Yingmai Shengli (Group 2) Tarim, NW China, were collected investigate sources, studied systematically for first time. The isotope basalts (between 0.29‰ ± 0.03‰ 0.32‰ 0.05‰) are higher than primitive (δ66Zn = 0.16‰ 0.06‰) but similar those mid-ocean-ridge (MORB; 0.24‰−0.31‰). Considering high fractionation (e.g., Mg# 0.28−0.37) crustal contamination (87Sr/86Sri 0.70720 0.70779; εNd −3.2 −1.9), may not conclusively point a carbonated source. In contrast, show heavy 0.39‰ 0.03‰), nonradiogenic 87Sr/86Sri (0.70459‒0.70518) εNd(t) −1.3 0.1) signatures, less (Mg# 0.46−0.71), implying components Nonetheless, lack negative Zr, Hf, Ti anomalies, low CaO/Al2O3 ratios, SiO2 contents preclude direct melting carbonate-bearing Alternatively, these features suggest decarbonated subducted eclogite variable interaction with subsolidus peridotite. This assumption consistent positive correlations Gd/Yb Sm/Yb ratios content as result mixing eclogite-derived high-δ66Zn melt peridotite-derived mantle-like melt. Our study provides new model reconcile geochemical Tarim highlights basalts.