N. Sr, Hf and Pb isotopes Basalts erupted on volcanic seafloor range from 17.8 to 18.0 for 206 Pb/ 204 Pb, vol.15

, Sr/ 86 Sr. Basalts erupted on ultramafic seafloor range from 17.7 to 17.9 for 206 Pb/ 204 Pb

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