Large Zn isotope variations in lower oceanic crust offer insights into oceanic crustal magma plumbing system

S1-S11, and Tables S1-S8. Supplementary texts include 1) detailed description of analytical methods, 2) calculation of parental magma liquidus temperatures, 3) calculation of post-cumulus melt evolution temperatures, 4) estimation of sulfide modes, 5) thermodynamic modeling of MOR magma fractional crystallization, 6) geochemical modeling to reproduce Cpx REE data of the cumulates, 7) geochemical modeling to reproduce the whole-rock Zn isotopic data, and 8) thermodynamic modeling of lithological distributions in lower oceanic crust.

Supplementary figures include 1) geological map of the Kane and Atlantis Bank OCC (Fig. S1), 2) representative photomicrographs of the Kane and U1473A cumulates (Fig. S2), 3) whole-rock REE patterns of the Kane and U1473A cumulates (Fig. S3), 4) the calculated Tliquidus, Tsolidus, and TH94 (Fig. S4), 5) the calculated Zn fractions in oxides, silicates, and trapped melts (Fig. S5), 6) plots of Zn isotopes against selected geochemical proxies (Fig. S6), 7) correlation coefficients (expressed as R values) of δ66Zn with incompatible element concentration and ratios (Fig. S7), 8) modeled lithological distributions of the lower oceanic crusts (Fig. S8), 9) modeling of the influence of changing Ma/Mc values on the δ66Zn-Th correlations for the interstitial melts (Fig. S9), 10) modeling of the melt δ66Zn during partial melting of various mantle reservoirs (Fig. S10), and 11) results of phase equilibrium modeling of the studied cumulates (Fig. S11).