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The regression age is calculated using the ISOPLOT program. The analytical errors are smaller than the symbol. The dashed line with crossed symbols is the calculated isochron of 103.7 with an initial 187Os/188Os of 0.133. Global modern MORBs (EPR, mid-Atlantic ridge and Indian ridge) data are from Gannoun et al.21, Escrig et al.45 and Yang et al.46.
